Tidal Power

Tidal barrages have been used to generate power for decades, but environmental and economic issues have prevented their widespread adoption. Much more promising are tidal stream technologies - essentially underwater wind turbines. Though only in the early stages of development, they have the potential to be a large-scale energy source in future.

Image Source: Siemens UK

Tidal Power

By the Numbers

15 metres

Tidal range of Nova Scotia's Bay of Fundy, the largest in the world

152,000 MW

Total potential capacity of the 27 best locations in the world for tidal stream farms

3.7 cents/kWh

Cost of power generated by the La Rance in France tidal barrage, cheaper than most competitors

15,900 MW

Generating capacity of the proposed Severn tidal lagoons in the UK, costing $65 billion

$0.54 to $0.66 per MW

Cost of electricity from the first tidal stream farms, comparable to the cost of wind power in 1980


Countries currently investing in tidal power research

Last Updated: February 2017

Andrew Farris and Charlotte Helston

Tidal power exploits energy drawn from the movement of ocean tides to produce electricity. There are two main branches of technology that tap the tides for energy. The first and best known are tidal range technologies which harness power through dam-like structures that trap rising waters on one side and then release it back to the other through turbines that spin to generate electricity. The second technology is newer and just beginning to be tested out on a commercial scale around the world, so-called tidal stream technologies. They harness fast-flowing currents to spin turbines. Tidal stream turbines come in many shapes and sizes but the most common designs are basically underwater wind turbines.

Tidal energy is considered renewable because the tides move on a predictable, daily schedule, depending only on the orbits of the Earth, Moon, and Sun, and are essentially inexhaustible. Though tidal energy is carbon free, tidal range technologies have not proven to be environmentally benign. Concerns over the health of shoreline and aquatic ecosystems mar this otherwise clean source of energy.

Until the last decade large-scale tidal range systems dominated the tidal power scene. Yet severe environmental and economic drawbacks to this technology quickly became evident and this has stymied its development and prevented it from taking off. Though it has been around since the 1960s only a handful of tidal barrages have been built around the world.

The focus of research and development has shifted from tidal range systems to tidal stream technologies. Though more environmental studies have to be conducted on these new technologies, at this time they appear very promising. Power from tidal stream turbines is still very expensive, but the technology is still in its infancy and the industry today is often likened to the wind power industry 20 years ago. At that time wind power was hugely expensive but continued investment succeeded in bringing the price of wind farms down to where they are today, economically competitive with practically every power source.

Within Canada the provinces of Nova Scotia and BC are fantastically well suited for tidal development, given their tidal geography, and Nova Scotia is investing heavily in a future tidal power industry, and so far those investments appear to be beginning to pay off as foreign companies are setting up shop in the province to test out their tidal power designs. British Columbia got an early lead in tidal stream development with the Race Rocks Tidal Project in 2006, but has since fallen behind and the once promising industry is struggling to survive. Below we talk about

  1. Clark, 2006.

How Tidal Power Works

  • There are two main tidal power technologies called tidal range and tidal stream.
  • Tidal range facilities act like dams that trap the tides and then release the water to generate electricity.
  • Tidal stream technologies can be thought of as similar to underwater wind turbines.

Tides are created by the gravitational pull of the sun, moon and the rotation of the earth and tidal power generators work by harnessing their natural ebb and flow. Tidal energy can be harnessed both in the sea, and in tidal rivers and estuaries. The ebb and flow of tides can occur once or twice a day depending on location. Due to the upward gravitational rotation of the moon, the water level rises gradually until it reaches its highest point and then gradually falls back to its lowest point. One of the main advantages of tidal power over solar or wind power is that the tides are entirely predictable and power can be scheduled years in advance. The tide does not occur at the same time every day but rather fluctuates over a period of roughly two weeks.

There are two main tidal power generation technologies. The first are tidal range technologies that rely on the rise and fall of sea level to generate power. The second, tidal stream technologies, harness the currents created by tides.

Diagram of a tidal barrage.

The most common form of tidal range technology is the tidal barrage. It is essentially an adaptation of conventional hydroelectric dam technology. A wall is built that blocks off an existing tidal estuary with a dam, or barrage. Movable flood gates on the barrage—called sluice gates—allow incoming tidal waters to fill up in a reservoir. Once the water reaches its maximum level, the gates close and trap the water. This trapped water is called hydrostatic head.

As the tide ebbs, a gradually increasing head differential is created between receding water levels and the fixed level within the barrier. When the head differential has reached the desired value, the potential energy created can be converted into mechanical energy and then electrical energy by allowing the water to flow out through turbines. A proper site for this type of technology should have sufficient tidal range and the best locations are in natural bays. It is also important to locate the facility in such a way that it will not dramatically reduce the tidal range. One major drawback of tidal barrages is that the tide only goes out for so much time per day, and power is generated for as little as four hours a day, giving barrages low levels of efficiency in the 20-25% range.

Tidal barrage technology is not new and mills that use the tide for power date back to the 8th Century CE. The tidal mills were mainly used for grain grinding and were of similar design to the conventional water mills with the addition of a dam and reservoir. The technology fell out of favour after the Industrial Revolution until the 1960s to 1980s when experimental tidal barrages were built in France, Russia, China and Nova Scotia.

The La Rance tidal power plant in France is the world's second largest tidal barrage structure.

Tidal Lagoons and Dynamic Tidal Power

An artist's impression of the first tidal lagoon currently under construction off the coast of Wales. Later tidal lagoons would be detached from the coast altogether.

Past experience with tidal barrages has shown that walling off fragile and ecologically important coastal ecosystems, even for only a few hours a day, can be environmentally damaging, something we discuss in more detail below. As a result scientists and engineers have proposed several novel tidal range alternatives to the barrage, the furthest advanced being the tidal lagoon. Tidal lagoons would not be attached to the shoreline at all, but rather be artificially created pools in the sea itself that would let water in and out and generate power much the same way as tidal barrages, except with greater efficiency and without isolating ecologically sensitive inter-tidal areas.

As of early 2016 the first tidal lagoon project is under construction off the coast of the Welsh city of Swansea, enclosing around 11 km2 of water. It will produce 320 MW of power for 14 hours a day, enough to power 155,000 homes and making it the largest tidal energy facility in the world. Scheduled for completion in 2019, if successful it will be the first of six proposed tidal lagoon projects to be built on Britain’s west coast.

An even more radical and promising tidal range proposal is the Dutch-designed Dynamic Tidal Power system. A giant T-shaped pier would be built up to 60 km straight out from the coast, blocking tides that move parallel to the coast and cause enough head differential to could produce tremendous amounts of electricity, while possibly avoiding many of the economic and environmental problems of other tidal range technologies. No such projects have been built yet, but teams from China and the Netherlands are moving forward with planning on such projects.

Tidal Stream Technologies

Tidal stream technologies are the second class of tidal power generation schemes, and they act much like underwater wind turbines, generating power from the kinetic energy of fast-flowing tidal currents. The generators are sunk 20-30 meters, and can be situated anywhere that possesses a strong tidal flow.

Tidal stream technologies have seen huge advances in the last decade, with many companies around the world working to recreate the success of wind turbines on land in the underwater realm. Yet developing a successful tidal current turbine is much more difficult than simply dropping a wind turbine in the ocean.

Because water is about 800 times denser than air tidal stream turbines must be built much sturdier than their terrestrial counterparts, though they can also spin much more slowly, around 7-11 rotations per minute. Shrunken diameters help to reduce the structural strain. The advantage of greater density of water is that relatively large amounts of power can be produced with relatively small rotor diameters. For example: rotors with a diameter of 10-15 meters can generate as much as 700 kW of power, whereas a 600 kW wind turbine requires a rotor diameter of 45 meters. Tidal turbines function best at flow rates of 7-11 km/hr. An irrefutable advantage of tidal turbines over wind turbines is their predictability: Tides flow in and out every day, promising daily, schedulable energy.

Diagram of a proposed tidal stream generator. Because of water's density the blades would move very slowly, hugely reducing the risk to fish.

Yet the technology is far less mature than wind power, and tidal stream technologies are just now leaving the prototype and demonstration phase. Indeed, no single design of tidal turbine has been agreed upon yet. Companies around the world are pioneering 40 different designs, and while most function on the same principles as horizontal axis wind turbines, there are a host of other more novel designs such as vertical-axis turbines, rotating screws, tidal kites, and paddlewheels.

Research still needs to be done in a number of fields, the most important of which is making the turbines durable enough to survive the hostile aquatic environment: A test turbine in Nova Scotia had its rotors ripped off by the immense tidal forces in the Bay of Fundy. Corrosive salt water also takes a serious toll on equipment. They also need to be made more efficient and economical as the power they produce today remains prohibitively expensive. Experiments are also ongoing on the best method for mooring the turbines to the seafloor. While most common are those put on concrete bases on the sea bed, some designs have been mounted on towers, or are even made to float in the water, tethered to the seafloor with cables. Research is also being conducted on how best to hook these turbines up to the grid.

Ultimately, as the technology advances and the price comes down, as it inevitably will with continued investment, farms of tidal stream turbines will be laid on the seafloor (or floated above it). One field of ongoing research is determining the proper spacing and siting of the turbines to maximize power output. Avoiding this altogether is building tidal fences, a concrete structure filled with tidal turbines placed in a region of fast-flowing water, a channel between two land masses for instance. Fence installations are presumed to be less expensive to develop than tidal barrages, as well as less harmful to marine ecosystems.

No tidal fences, or farms of tidal current turbines, are yet in operation, though the first farm is currently under construction in Scotland. Their main component after all — tidal current turbines — are still in the development stages. But the technology is rapidly maturing and appears on the verge of a tipping point, much as wind and solar were 20 years ago.

Great leaps in the technologies are already being envisioned. All the designs under discussion right now are first generation tidal turbines and cannot operate deeper than 30 metres. Second generation devices, which may start entering the demonstration phase by 2020, will be much larger, generate much more power, and can be placed at much greater depths, opening up great new swaths of the ocean to tidal development.

An artist's conception of a tidal fence, a farm of tidal stream turbines. These particular models are based on the Seagen design, the world's first commercial tidal stream turbines. There are however many different designs under consideration.
Marine Turbines
  1. Ocean Energy Council, "What is Tidal Energy."
  2. Charlier. 2003.
  3. Hammons, 1993.
  4. Tidal Lagoon Power, "Swansea Bay."
  5. Renewable Energy World, "Advances in Dynamic Tidal Power Technology."
  6. Harvey, 2010.
  7. Aubrecht, 2006.
  8. Garrett & Cummins, 2005.

Geography of Tidal Power

  • Tidal barrages are limited to locations like bays and estuaries.
  • There are many more locations where tidal stream turbines can be placed so long as the currents are fast enough.
Bay of Fundy at Low Tide
Samuel Wantman

Tidal power technology is only useful if it is employed in favourable conditions. Location is everything. For tidal barrages a tidal range of at least 7 metres is required, while tidal turbines need tidal currents moving at speeds of 7-11 km/hr. In addition both types must have stable conditions for a barrier or turbine to be built into. Often, good sites are located in areas where incoming waters are funneled into narrow channels, bays, river mouths and fjords.

There are only a limited number of places around the world where the tidal range is great enough to justify a barrage. The world's greatest tidal range is found in Canada's Bay of Fundy, where it is over 15 meters. Quebec’s Ungava Bay and numerous estuaries around the Pacific Northwest feature ideal tidal ranges as well. Around the world sites on the coasts of Argentina, Australia, India, South Korea, Mexico, the US and Russia offer the best potential sites for tidal barrage plants.

Developers of tidal turbines are seeking out locations that possess tidal streams — areas of quickly flowing water caused by the motion of the tides. Typically, tidal streams are found where underwater valleys force currents to constrict and speed up. These are generally more common and located nearer economic centres where the power would be useful.

Major tidal currents occur in the Bay of Fundy, the Gulfs of Saint Lawrence and Mexico, the Amazon and Rio de la Plata river estuaries, and straits like the Straits of Magellan, Gibraltar, Sicily, the Skagerrak-Kattegat separating Denmark and Sweden, and the Bosporus in Turkey. In the Far East, useful currents are found near Taiwan, Korea, and the Kurile Islands north of Japan.

The United Kingdom, whose rugged coast is punctuated by inlets and surrounded by islands, is extremely well suited for both kinds of tidal development and has taken an early lead in the field. These locations include the Bristol Channel, Pentland Firth, the Hebrides, in the Irish Sea, the North Channel, Alderney Race, the Isle of Wight, the Orkneys and the Shetlands. A recent study by Oxford University found Scotland’s Pentland Firth to be “almost certainly the best site for tidal stream power in the world,” with enough potential energy to fulfill half of Scotland’s power needs.

How much power could this all add up to? There are considerable quantities of untapped tidal energy in waters all around the world and it is difficult to precisely calculate just how much power could be derived from it. One estimate by the International Renewable Energy Agency puts global potential resources at 3 TW. A study by the European Innovation Partnerships for Water, a think tank, picked the 27 most promising locations for tidal barrages in the world and pegged their total capacity at 152,000 MW. Tidal lagoons and Dynamic Tidal Power plants could theoretically multiply that number several times over.

The total potential of tidal stream technologies will likely change as the technology matures and more countries begin carefully mapping their tidal resources, a task the leading countries only began recently. Nevertheless, Atlantis Resources, a British Tidal power company, estimates 90,000 MW of generating capacity could be built, for a total of 150 TWh of power a year.

Map showing the places with the best potential for tidal power.
  1. Colazingari, 2008.
  2. Aubrecht, 2006.
  3. Charlier. 2003.
  4. Tidal Energy Today, "Estimate of global potential tidal resources."
  5. International Renewable Energy Agency, 2014.
  6. European Innovations Projects, “Annex 6 Potentials for tidal barrages, tidal flows and osmotic power.”
  7. European Innovations Projects, “Annex 6 Potentials for tidal barrages, tidal flows and osmotic power.”

Economics of Tidal Power

  • Tidal power is currently very expensive but the price of tidal stream turbines may drop sharply as the technology develops.

The Economics of Tidal Range Technologies

Large tidal barrages present three main problems for skittish investors: they have large up-front capital costs, long construction times and produce relatively limited quantities of power. This is somewhat balanced out by operational lives of 100 years. Once over that initial capital building cost hump, tidal barrages become attractive investments. Studies peg maintenance and operations over the barrage’s century long lifespan at less than 0.5% of initial capital costs. Much depends on the site, the two decisive economic inputs being the size of the reservoir basin and the tidal range. The first determines how long power can be produced and the second at what efficiency. Costs generally increase for sites that experience violent winds and waves, as dykes must be built stronger and larger to withstand them.

The La Rance tidal barrage in France conveniently doubles as a major bridge, enhancing the facility's value considerably.
EDF Pulse

Despite having been around for decades, tidal barrage technology is not well developed. There are only four real examples to draw economic conclusions from, not enough to have any clear idea of just how expensive any proposed barrage will end up being. An estimate is given by researcher Eleanor Denny. She argued that in order for a tidal barrage facility to be profitable, its capital cost should be less $800,000 per MegaWatt of installed capacity. Unfortunately this is an unrealistically low cost. According to IRENA the La Rance project hurtled past this when their construction budget came out to $817 million in today’s dollars, or $3.4 million per MW. Korea’s Sihwa Lake design was much more economical costing $298 million, or $1.17 million a MW. Both barrages also double up as highway bridges which adds as much as 40% more value to the structure over and above mere power production. Nevertheless it appears Sihwa Lake was a model of economic stewardship that will be difficult to repeat, and few of the other proposed tidal barrage projects around the world even come close to Denny’s profitability target. This will likely be a significant roadblock to their eventual construction.

Once people get past the initial sticker shock however they find electricity prices to be a pleasant surprise. After 50 years of operation the La Rance power plant provides electricity at bargain-basement price of 3.7 cents/kWh, much cheaper than the 10.8 cents/kWh charged by coal thermal plants in the area. The cost is even lower than that of France's nuclear power, which is 3.8 cents/kWh. Only hydroelectric plants, at 3.2 cents, are more efficient. The price could be brought down much further if bi-directional turbines that generate electricity on both the ebb and flow of the tide, which will likely happen on future projects.

Tidal Lagoon Power is pushing a tremendously ambitious proposal for a series of six tidal lagoons off Britain’s western coast to be completed by 2027, each one bigger than the last for a combined total of 15,900 MW of generating capacity. Building these six facilities will cost some $65 billion, and in the process nurture a British tidal lagoon industry that can export their expertise around the world (Canada is at the very top of their list). Unfortunately the costs will be high, at $4 million per MW. On the other hand the economies of scale provided by this gigantic plan and their 120-year-lifespan would be huge advantages. A levelized cost analysis by Poyry, an engineering consultancy, found the tidal lagoons would be cost competitive with wind and solar power, and even nuclear and gas power which are the cheapest power sources available.

The Economics of Tidal Stream Technologies

Tidal stream technologies are essentially a decade old, and have only begun making great strides in the past five years. As yet the price is very high but it is almost certain dramatic price drops will accrue over time. Furthermore any scale of tidal stream turbines can be built as opposed to one giant project for barrages, giving developers much greater flexibility. Farms don’t have to be built in one go, like tidal barrages, but gradually expanded over time. An in-depth economic analysis by the Carbontrust found the bulk of costs in early tidal stream farms will be in the installation, about 35% of the total, with operations and maintenance (20%), station keeping (20%), power takeoff (10%), the structure (10%) and grid connection (5%) accounting for the remainder. Early British farms of about 10 MW will produce power at a range of $0.54 to $0.66 per KWh. This may sound expensive but we must remember this is roughly the cost of wind power in 1980.

Nevertheless these numbers leave much to be desired, especially as the 2012 Carbontrust estimate was actually double their previous 2006 estimate. The 2006 estimate was made before anyone had actually experimented with a tidal stream turbine in real world conditions, and only through experimentation did developers learn the huge technical challenges getting the technology to work posed. They also admitted that in 2006 their assessment of future decreases in price was over-optimistic about, a reminder that though it is likely tidal will one day be cheap enough to compete with other forms of renewable energy, it will take time.

Picking the best tidal sites is absolutely key to determining future energy cost. The two main determining factors for tidal stream projects are depth (the shallower the project the easier to install and maintain) and speed of tidal current (how much power can be had). If the best sites are developed early this will help bring costs down through learning, and allow a smoother rise in capacity. Building those early farms bigger is better too. The cost per MW of power in a 150 MW farm would likely be half that in a 10 MW farm. Finally as the tidal farm developers move along the learning curve they will discover cheaper and more efficient ways to build, install and repair every part of the turbine, from carbon-fibre rotor blades, lightweight fibre mooring systems and linear generators. All together costs will need to come down 50% to make tidal stream generation with offshore wind generation, itself on the expensive side of the spectrum of commercially viable renewables. This appears entirely achievable though how long it takes will depend entirely on the amount of money invested in pushing the limits of the technology.

Economic Effects on Tourism and Fishing

An increase in tourism has been observed at Canada's Annapolis tidal plant, as well as at France's La Rance plant. More than 40,000 tourists visit the Annapolis facility each year. Sites have a potential to double as information centers, employing individuals in a range of tourism positions, in addition to the general operation jobs created by the power plant itself. Temporary construction jobs are opened up as well during the installation of the facilities.

On the other hand negative environmental effects on marine life can be detrimental to the fishing industry. Some fishermen have raised concerns over the fact that most identified sites for tidal power are also key migration routes for fish. Additionally, sedimentation caused by tidal barrages could kill clams, while also damaging local shellfish fisheries. The La Rance facility displayed no major effects on the immediate fish community or local fisheries. The area, however, had a minute fishing industry to begin with and no professional fisherman after 1960. Impacts are expected to be much more apparent in locations where fish are abundant and fish passage is repeated by the same populations multiple times over the year, such as Canada's Bay of Fundy site.

  1. Hammons, 1993.
  2. Meygen Limited, “Pentland Firth/Inner Sound.”
  3. Meygen Limited, “Pentland Firth/Inner Sound.”
  4. Denny, 2010.
  5. Williams, 2010.
  6. Tidal Lagoon Power, "Swansea Bay."
  7. Poyry, 2014.
  8. Denny, 2010.
  9. Government of Denmark, 2015.
  10. Carbon Trust, 2011.
  11. European Innovations Projects, “Annex 6 Potentials for tidal barrages, tidal flows and osmotic power.”
  12. Johnson, 2006.
  13. American Fisheries Society, 2010.
  14. Pollack, 2008.

Tidal Power's Environmental Issues

  • Tidal barrages can have large negative impacts on marine ecosystems, but lagoons may be better.
  • Early research indicates tidal stream turbines do much less damage.

Environmental Effects of Tidal Barrages

The environmental effects of tidal barrages vary enormously from site to site, but they tend to be quite striking. A 2010 study examined ecological impacts at the Kislaya Guba tidal power plant in Russia. The 400 kW plant was completed in 1968 and continues to run to this day. An environmental evaluation of the Kislaya site sponsored by UNESCO provides a general assessment of the potential risks associated with tidal barrage power plants.

Prior to development, Kislaya Guba Bay was a fjord with a rich array of marine life. During the four years it took to construct the power plant, the bay was closed off from the sea by a dike. Water exchange was massively reduced to several percent of the natural exchange. The lack of moving water permitted the entire bay to freeze over in the winter, which annihilated coastal biota to a depth of 5m (15m where oxygen was depleted and accumulated hydrogen sulfide contaminated the water). Evidence of ecosystem damage can be found in the abundance of dead mollusks in the bay. The study did indicate some environmental recovery about 20 years after the initial construction, though it is not the same ecosystem it once was and continuing impacts of operation include: "diminution of tides, diminution of sea swells, reduction in the flow of fresh water from the partitioned water area to the sea, and the mechanical effect of the turbine on plankton and fish.” It is thought that with experience and better environmental assessments, future projects could avoid at least some of the pitfalls encountered by this Soviet-era engineering project.

The Lake Shiwa tidal barrage in South Korea.

In general, tidal barrages reduce the tidal range by about half; diminishing the intertidal zone and instigating a ripple of effects through the coastal ecosystem. The intertidal area provides a key feeding ground for birds. When the condition of this area is compromised, birds are likely to starve, or else forage for food in new ecosystems, potentially offsetting the natural balance there. The trapping of salt waters, where they would naturally flow into delicate salt marshes, can cause these areas to become diluted with fresh water, destroying a formerly intact ecosystem. Some estuaries may have formerly provided nurseries for breeding fish that would be jeopardized by tidal power development. It is also possible for fish and marine mammals to suffer damage or death by collision with the barrage or turbines, though fish passages and ladders can be used with varying degrees of success.

The macrotidal estuaries of the Bay of Fundy, for instance, are used by large numbers of migratory fish, including dogfish, sturgeon, herring, shad, Atlantic salmon and striped bass, as well as larger marine animals such as squid, sharks, seals and whales. Studies have shown that fish passage utilizing the Annapolis estuary has a disastrous turbine related mortality of 20-80% per passage depending on fish species. Injury or mortality of fish can occur in several ways during turbine passage, including mechanical strike, shear (the fish is caught between two streams with different velocities), pressure changes and cavitation (implosion of air bubbles which produces shock waves). The study of Annapolis estuary concluded "that introduction of tidal turbines into open ocean current systems will cause widespread impact on marine populations resulting in significant declines in abundance."

These environmental issues have made governments outside of Korea reluctant to invest in tidal barrages. Studies on the major proposed tidal barrage on the Severn Estuary in England have shown that in the planned basin the minimum water levels would raise enough to permanently flood 80 km2 of intertidal habitats that are essential for the dozens of migratory birds species who stop and nest there. As a result plans to build that barrage have been scrapped.

A series of six tidal lagoons have been proposed instead. They would avoid most of the problems associated with the barrage because they would not impound valuable inter-tidal areas, with the lagoon walls being at their closest about 1.5 km from the coast. At the same time they would extract twice as much energy from the same size of impounded area. As such the tidal lagoon plan has won endorsement from a variety of environmental groups.

The operation of tidal barrages or lagoons does not create greenhouse gases, though their construction does. Greenhouse gas emissions were estimated at 20.5 megatonnes for the construction and operation of the now cancelled Severn Barrage. This may sound like a lot but if this plant was to replace a coal-fired plant then it would pay back all the potential emissions from its construction within 6 months of beginning operation.

Environmental Effects of Tidal Stream Technologies

A Meygen tidal stream generator being deployed off the coast of Scotland. Meygen hopes to have 398 MW of generating capacity by the early 2020s.

Many studies are being conducted to determine the environmental impact of tidal stream turbines and results so far have been very promising. As the turbines turn much slower than wind turbines, 7-11 RPM for most designs, they move much too slowly to chop up fish or marine mammals as wind turbines do to birds. Research conducted in New York and Maine shows that marine life generally avoids the swinging blades of the turbines anyway, and so far the researchers have found no evidence of damage to fish. Noise from the turbines is another potential issue as marine life can be notoriously sensitive to noise. A study by the U.S. Department of Energy found that young salmon exposed to turbines for “extreme” amounts of time suffered small yet measurable amounts of tissue damage, though the effects lessened as they matured. More study will be required but all in all these were encouraging results.

The placement of arrays of turbines into farms will necessarily slow and reroute currents over a wide area, potentially disrupting fish migration patterns or leading to harmful variations in water pressure. The changes in currents can have an impact upon the ebb and flow of the tides on land, changing their range and impacting inter-tidal ecosystems much like barrages. Irish researchers studying this question found that the impacts could be mitigated enough to make large scale arrays feasible if the turbines were spaced five rotor diameters apart. When gigantic tidal arrays of 8,000 MW were plugged into one study of Scotland’s Pentland Firth researchers found tidal range could be affected by as much as 10% hundreds of kilometres away. On the other hand the farm caused a decrease in turbidity, or sediment in the water, allowing sunlight to penetrate down and trigger phytoplankton blooms which had the effect of boosting the food chain positively from the bottom upwards.

While many of the tests are still preliminary, and scientists have only computer models to go by on the effects of farm arrays, the environmental impacts of tidal stream technologies are generally less than almost all other energy sources.

The carbon emissions from tidal stream technologies derive from the construction, installation and operation of the turbines. In all likelihood the lifecycle carbon emissions from this power source will be comparable to wind and solar.

  1. Fedorov & Shilin, 2010.
  2. Clark, 2006.
  3. Clark, 2006.
  4. Dadswell & Rulifson, 1994.
  5. Zhou, Falconer, & Lin, 2014.
  6. Friends of the Earth Cymru, 2004.
  7. Fallon, Hartnett & Olbert, 2014.
  8. Clark, 2006.

Politics of Tidal Power

  • The success of wind power indicates the success of tidal power will depend on sustained government investment.
A diver conducts research on a demonstration tidal stream generator in the United Kingdom.
Offshore Wind

On the face of it tidal power would seem to be a total slam dunk from a political perspective. Not only is it carbon-free and renewable, but unlike wind and solar power the tides are entirely predictable and reliable. Furthermore they do not create unsightly views for locals, like wind power, or require large amounts of land like solar, thus neutralizing powerful NIMBY lobbies. Yet the initial hopes placed in tidal barrage power turned sour when France’s pioneering La Rance project inflicted considerable environmental havoc on surrounding marine ecosystems and did not produce enough electricity to justify the construction costs. The only country currently pressing forward with aggressive tidal barrage development schemes is South Korea, though the British government may eventually move forward with tidal lagoon schemes and China with Dynamic Tidal Power.

Tidal stream technologies have only in the past five years begun to mature, and these hold out the prospect of someday bearing bountiful fruit. Governments around the world are sitting up and taking interest and the field is quickly becoming crowded. 19 countries, from Latin America to East Asia, Europe and North America are actively investing in tidal power development. According to a 2014 study by the International Renewable Energy Agency 15 national governments are funding research and demonstration projects, 12 have set up marine testing areas and 11 have imposed feed-in tariffs that subsidize energy to the grid produced by tidal projects. 9 countries have explicit targets for ocean energy generation, the most ambitious of which is France’s goal to have 380 MW of capacity by 2020. Nova Scotia’s 300 MW by 2020 plan is perhaps the world’s most ambitious as France already has 240 MW from the La Rance facility.

Previous experience with wind and solar power shows that it will require sustained and consistent government investment to take these technologies from the drawing board to the demonstration phase and ultimately the commercial utility phase. Once these early steps are taken costs plummet and the companies that developed the early technologies grow to become global giants. Wind generated electricity, for instance, has declined in price over 90% since 1980, making it competitive with most forms of energy production. If the Danish example is anything to go by this robust government investment will be doubly important as Denmark’s early wind power pioneers were working out of garages and small university departments on shoe-string budgets. The unavoidable expenses of designing, placing and testing turbines in an underwater environment means this cottage industry beginning will not be replicable for tidal power. The tidal power companies that will be household names 30 years from now will be those with the kind of economic muscle backing them that can only be provided by governments and large corporations.

  1. Marine Renewables Canada, “Marine Renewables Energy in Canada.”
  2. International Renewable Energy Agency, 2014.

Tidal Power Around the World

  • Traditional tidal range technologies have largely stalled outside Korea.
  • More exotic tidal lagoons and DPS systems are being examined in the UK and China.
  • Tidal stream technologies are moving forward rapidly around the world.

Status of Tidal Range Technologies in 2016

The first modern tidal barrage was built in La Rance, France, on the Cherbourg Peninsula in 1966. With a nameplate capacity of 240 MW the facility generates about half a billion kWh annually using 24 low-head Kaplan turbines. Since then only a handful of tidal barrages have been built around the world, including one in Annapolis, Nova Scotia and several small ones in China and Russia.

The only recent major tidal barrage was built at Lake Shiwa in South Korea, which opened in 2011. It has a peak capacity of 254MW and yearly production of 552.7 GWh. The plant was built on the footprint of an old seawall, mitigating much of the environmental damage that has prevented tidal barrage development elsewhere. Currently, the Koreans are looking into the possibility of building and expanding seven more facilities, including the second largest tidal barrage, the Icheron, with potential of 700-1000MW. They are the only country actively pursuing new tidal barrage projects in 2016.

Indicative of the status of tidal barrage technology today is the Severn Barrage which had been proposed for the mouth of the Severn between Bristol and Cardiff. The idea of a tidal power plant on this spot dates to 1925, but justifying the excessive power costs and the environmental damage that would result led the British Government to all but kill the project in 2013. Tidal lagoons have been proposed for the site instead, and the first one is expected to be completed in 2019. For these reasons it seems unlikely much further development of tidal barrages will occur, though tidal lagoons show some promise. The main remaining hope for tidal range technologies remains the gargantuan Dynamic Tidal Power plants proposed for China, though these remain a long way off from being realized.

Status of Tidal Stream Technologies in 2016

The Seagen tidal stream generator.

Tidal current turbines have been on the minds of engineers and scientists since the 1970s, but only in the past eight years have they seen sustained investment. As of now the entire sector looks about ready to take off. The British company Marine Current Turbines (MCT) paved the way for tidal projects when it unveiled its SeaGen turbine in 2008. The 1.2 MW tidal energy converter is located in northern Ireland where it provides enough power for about 1,000 homes. Since SeaGen's success, numerous plans for development and pilot projects have emerged, and about 40 different turbine designs are being tested out around the world with the United Kingdom leading the development effort. They are supported by a small club of other countries, with the US, Canada, Norway and the Netherlands having the most active development.

Most of the teams working in these countries were small groups working at universities, with little industrial cohesion and no economies of scale. Nevertheless they have done important pioneering work and the first tidal stream farms are finally being planned. In Scotland construction of the Meygen Project, the world’s first tidal farm, began in early 2015. Meygen will see the carpeting of the seafloor in Pentland Firth with 398 MW worth of 1.5 MW turbines.

In what is perhaps the strongest sign yet that tidal stream technology is reaching a tipping point, the world’s industrial engineering giants are entering the fray, beginning to design their own tidal turbines. Companies like Korea’s Hyundai Heavy Industries, Germany’s Siemens, America’s Lockheed Martin and Japan’s Kawasaki Heavy Industries. If these companies bring their turbine building expertise to bear and dramatically increase the efficiency of the turbines—one Lockheed design has a capacity of 15 MW—then tidal stream technology may start to see the sort of investment needed to catch up with wind and solar.

  1. International Renewable Energy Agency, 2014.
  2. Meygen Limited, “Pentland Firth/Inner Sound.”

Tidal Power in Canada

  • Nova Scotia and B.C. have the greatest tidal power potential and their industries are discussed in depth in this article.
The Race Rocks tidal current turbine prior to installation just off the coast of Victoria. This was the only operational tidal power plant in British Columbia before it was decommissioned.
Gary Fletcher

Because of its geography and innovative entrepreneurs and engineers, Canada is one of the world’s leaders in tidal power. Canada's enormous tidal energy potential exceeds 42 GW, making the country one of the best places for tidal development in the world. There have been 190 suitable sites identified, with BC having the most and Nunavut the greatest total potential. So far most development of tidal power in Canada has been limited to British Columbia and Nova Scotia. The Bay of Fundy, which lies between New Brunswick and Nova Scotia, is Canada's — and possibly the world's — most promising location for tidal power development. Each day, volumes of water in excess of 100 billion tons flow in and out of the bay. That's more than all the world's freshwater rivers combined.

Nova Scotia is betting big on tidal power and has put in place a variety of incentives to encourage research and development of tidal stream technologies and has succeeded in securing foreign investment from a variety of global leaders in the field. The government’s immediate target is for 300 MW of tidal power to be operating in the province by 2020. The nascent tidal power industry may wind up bringing billions in investments and tens of thousands of jobs to Nova Scotia.

British Columbia was also an early leader in tidal stream technology, boasting one of the world’s first demonstration projects at Race Rocks just south of Victoria. Since then however the attitudes of the B.C. and Nova Scotia governments towards the tidal power industries has been a study in contrasts, and British Columbia’s tidal power industry has been left to wither on the vine. This is unfortunate as B.C. has world-class tidal resources and several companies with cutting edge designs that could revolutionize the industry.

A map showing potential tidal resources in Canada.
Johnson 2006
  1. Cameron, 2011.
  2. Marine Renewables Canada, “Marine Renewables Energy in Canada.”


To ensure continuity of material, all of the external web pages referenced here were cached in the course of research.

Readers are recommended to search current links for any changes.

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When no treaty was signed between the government, and no war was fought over the land, first nations groups in Canada are entitled to the land on which they have historically lived and still inhabit.
In solar thermal energy collectors, the Absorber Area refers to the area absorbing the radiation
A technique where acidic solutions are pumped into a well, melting away debris about the bottom of the well and allowing the gas to flow more freely.
An electrical current that reverses its direction at regularly recurring intervals. Abbreviated to AC.
A series of processes in which microorganisms break down biodegradable material in the absence of oxygen. Used for industrial and/or domestic purposes to manage waste and/or release energy.
A device used for measuring wind speed.
The average speed (and direction) of the wind over the course of a year.
Asia-Pacific Economic Cooperation (APEC): A 21-nation group of Pacific-Rim nations that seeks to promote free trade, raise living standards, education levels and sustainable economic policies. Canada is a member.
The artificially increased discharge of water during the operation of hydroelectric turbines during periods of peak demand.
Small particles released into the atmosphere as part of the flue gases from a coal plant. Fly ash is dangerous for human health but most power plants use electrostatic precipitators to capture it before release.
The waters off the Atlantic provinces that has been producing oil and gas since the 1990s, and continues to have considerable untapped oil and gas potential. The region has similar geology to the oil-rich North Sea.
'The ionizing radiation which we are all inescapably exposed to every day. It comes from radon gas in the ground, the sun, distant supernovas, and even elements inside our own bodies. The average exposure is around 361 mrem per year for a person in Washington state (it varies by region).
Base-load power is that provided continuously, virtually year-round to satisfy a regions minimum electricity needs. Hydro and nuclear power are well-suited for base-load grid needs.
A renewable fuel in which soy or canola oil is refined through a special process and blended with standard diesel oil. Biodiesel does not contain ethanol, but research is underway to develop diesel blends with ethanol.
Renewable energy made available from materials derived from biological sources.
Natural gas, or methane, that is created by microbes consuming organic matter. Usually found near the Earths surface and is usually immediately released into the atmosphere.
Biological material from living, or recently living organisms such as trees, grasses, and agricultural crops. As an energy source, biomass can either be used directly, or converted into other energy products such as biofuel.
A facility that integrates biomass conversion processes and equipment to produce fuels, power, and chemicals from biomass. The biorefinery concept is analogous to petroleum refineries, which produce multiple fuels and products from petroleum.
Bitumen is "petroleum that exists in the semi-solid or solid phase in natural deposits. Bitumen is a thick, sticky form of crude oil, so heavy and viscous (thick) that it will not flow unless heated or diluted with lighter hydrocarbons. At room temperature, it is much like cold molasses."
Bottom Ash: Bottom ash are small particles that result from coal combustion, but unlike fly ash they are too heavy to be released into the atmosphere and must be stored.
Canadian Environmental Protection Act: Passed in 1999, CEPA is "An Act respecting pollution prevention and the protection of the environment and human health in order to contribute to sustainable development."
Cap and Trade: A system where the government sets a limit on how much of a pollutant may be emitted. It then sells the rights to emit that pollutant to companies, known as carbon credits, and allows them to trade the credits with other companies. The EU has implemented a cap and trade program for carbon dioxide.
Carbon Footprint: A calculation based on the set of greenhouse gas (GHG) emissions caused by an organization, event, product, or person.
Carbon Sink: A carbon sink is a natural or artificial reservoir that accumulates and stores carbon-containing chemical compounds for an indefinite period.
Carbon Monoxide: A deadly gas produced from the tailpipe of cars that burn gasoline.
Capacity Factor: The ratio of the actual output of a power plant over a period of time and its potential to output if it had operated at full nameplate capacity the entire time.
Cellulose: An organic compound consisting of several hundred to over ten thousand linked glucose units. Cellulose comprises the structural component of the cell wall in plants, many green algae. It is the most common organic compound on Earth comprising about 33% of plant matter.
Cellulosic Biomass: Fuel produced from wood, grasses, or the non-edible parts of plants that is mainly comprised of cellulose.
Cellulosic Feedstock: The inedible cellulose which comprises most plants and trees. Yields are much higher as any part of the plant can be used and because they do not compete with food, therefore, cellulosic feedstock is an ideal candidate for large scale sustainable biofuel production.
Cetane Rating: Also known as cetane number (CN), this is a measurement of the combustion quality of diesel fuel during compression ignition. It is a significant expression of diesel fuel quality.
Clean Power Call: A request sent out by B.C. Hydro to private power utilities for new electricity-generating projects totalling 5,000 GWh/year. B.C. Hydro will help fund the successful projects and then buy power from them once completed.
How efficiently a turbine converts the energy in wind into electricity. Just divide the electrical power output by the wind energy input.
Using the energy left over from one primary energy conversion to fuel another. The most prominent example of this are natural gas co-generation plants which first feed fuel into a gas turbine. The residual heat from that reaction then heats water to spin a steam turbine.
Collector Area: In solar thermal energy collectors, the Collector Area refers to the area that intercepts the solar radiation.
A mixture of hydrocarbons present in natural gas. When gas is lowered below the hydrocarbon dew point, a condensate, that is, a liquid, forms. These can be used for combustion just like oil and gas. These are also known as natural gas liquids.
Generation of electricity using fossil fuels.
Gas reserves that form beneath porous layers of sandstone. Until recently this has been the only kind of gas commercially extracted.
When bituminous coal is baked at high temperatures it fuses together ash and carbon, creating coke. Coke can then be used to reduce the oxygen content of iron, strengthening it and creating steel.
A force generated by to the earths rotation which deflects a body of fluid or gas moving relative to the earths surface to the right in the northern hemisphere and to the left in the southern hemisphere. It is at its maximum at the poles and zero at the equator.
Decentralized Electricity Generation: Decentralizated electricity generation is a concept used to describe a large number of dispersed energy generators, often closely integrated with the people that use the electricity. Wind turbines and solar panels are good examples: they can be put within communities, be owned by members of the community and generate electricity for it. Alternatively centralized energy generation, far more common in North America, is where a small number of large plants owned by utility companies (hydro-electric, nuclear or fossil fuel) generate large quantities of electricity.
The portion of the oil business that involves refining the crude oil, bringing it to market and selling it. Gasoline service stations are the most lucrative part of downstream operations.
Effluents: Gases or liquids released by a human-made structure, in this case flue gases from a coal-fired power plant.
Electrolyte: Usually a solution of acids, bases, or salts, electrolytes are substances with free ions which make them effective electrical conductors.
Electrolysis: A simple technique for splitting water atoms to obtain hydrogen, driven by an electrical current.
Requirements that set specific limits to the amount of pollutants that can be released into the environment by automobiles and other powered vehicles, as well as emissions generated by industry, power plants, and small equipment.
Transforming one form of energy into another. Most energy conversions that run our economy are conversions from a primary source to electricity (wind or nuclear) or movement (oil).
Energy Currency: Energy that is usable for practical purposes. These include electricity and petroleum which power appliances and vehicles.
A measurement of the amount of energy stored in a given volume.
Energy Return On Investment (EROI): This is the ratio of usable energy obtained over the amount of energy required to get it. The oil sands has a low EROI because instead of being sucked out of the ground in liquid form the oil must be painstakingly mined and heavily refined, a process that requires large quantities of energy itself.
An energy source is the means by which energy is generated. The energy profiles each deal with a different source of energy, and most are simply means to attain the energy currency we all use: electricity.
Enhanced Geothermal System: A new technology, EGS does not require natural convective geothermal resources, but instead can draw power from the ground through extremely dry and impermeable rock.
The provincial Environmental Assessment Office is a politically neutral agency tasked with reviewing major construction projects in B.C. Their purview includes assessing the environmental, economic, social, heritage and health effects over the lifecycle of projects.
A blend of ethanol and diesel fuel. plus other additives, designed to reduce air pollution from heavy equipment, city buses and other vehicles that operate on diesel engines.
A policy device that encourages investment in renewable energies, usually by guaranteeing power producers that their energy will be bought.
In food processing, fermentation is the conversion of carbohydrates to alcohols and carbon dioxide or organic acids using yeasts, bacteria or a combination thereof, under anaerobic conditions. In simple terms, fermentation is the chemical conversion of sugars to ethanol.
A finite, or non-renewable resource, is one where a limited amount exists. Once the existing stocks of that resource are exhausted there will be no more, at least in any reasonable human time scale. Only so much fossil fuels and uranium exist on earth, making these finite, non-renewableresources. The wind, sun and tides are renewable resources since it is impossible to run out of them.
First Generation Renewable: Well established renewable technologies that emerged early on in the Industrial Revolution. These include hydropower, biomass combustion and early geothermal power.
Fission is a nuclear reaction where a heavy atom is hit by a neutron, causing it to split into lighter atoms, release more neutrons, and huge amounts of energy.
Flat-plate collectors are a type of non-concentrating solar energy collector, typically used when temperatures are below 200 degrees F. They are often used for heating buildings.
Flex-Fuel Vehicle: Also known as a dual-fuel vehicle, this is an alternative fuel vehicle with an internal combustion engine designed to run on more than one fuel, usually gasoline blended with either ethanol or methanol fuel.
Flue gases are the gases that are released into the atmosphere by a flue, or pipe, from the steam boiler.
Many biofuel feedstocks such as corn, sugarcane, and soybeans are also key sources of food for millions of people. Production of crops for bioenergy may displace other food-related crops, increasing the cost and decreasing the availability of food. The central question is one of ethics: Should we use our limited land resources to grow biofuels when the same land could be producing food for people?
Fracking: Hydraulic fracturing is the process of injecting high pressure fluids into deep, geologic formations, in order to fracture the rock and render it more permeable.
Fuel Crops: Crops grown specifically for their value as fuel to make biofuels or for their energy content.
Fumaroles: Openings in the Earths crust that emit steam and gases.
Gasohol: Otherwise known as fuel ethanol, gasohol has been distilled and dehydrated to create a high-octane, water free alcohol. All water must be removed because a water-alcohol mixture cannot dissolve in gasoline. Fuel ethanol is made unfit for drinking by adding a small amount of a noxious substance such as gasoline.
Geothermal Gradient: The rate at which temperature increases deeper into the earth, towards the earth's molten core.
Geothermal Task Force Team is a government program that aims to: develop policies, in collaboration with affected agencies, related to tenure issuance, examine the regulation of the use of geothermal resources not currently covered by legislation, build a royalty and resource rent model for geothermal resources, and develop a science based review of the known geothermal resources in the province.
Geyser: Springs characterized by intermittent discharge of water ejected turbulently and accompanied by steam.
Giromill Turbine: Uses lift forces generated by vertical aerofoils to convert wind energy into rotational mechanical energy. They are powered by two or three vertical aerofoils attached to a central mast by horizontal supports.
Glut: A situation where the market has been flooded with goods and there is more supply than there is demand causing the price of goods to drop.
Gravity Survey: A technique of measuring minute changes in the Earths gravity field. This allows geologists to map lighter and denser rocks underground.
Green Energy and Green Economy Act of 2009: Legislation by the province of B.C. to boost the investment in renewable energy projects and increase conservation, create green jobs and economic growth in Ontario. Part of Ontario's plan to become a leading green economy in North America.
Head: The term head refers to the change in elevation of the water.
Head Differential: The difference in pressure due to the difference in height of water level.
Heat Exchangers: These are used in High-Temperature and Low-Temperature applications to transfer heat from one medium to another. In Low-Temperature Geoexchange systems they are built into the heat pump.
Horizontal Axis Wind Turbine (HAWT): Horizontal Axis Wind Turbine. These are the most common types of wind turbines and look like aircraft propellers mounted atop towers.
Hydrocarbons: A compound of almost entirely hydrogen and carbon. This covers oil and natural gas. Coal, the third fossil fuel, contains so many impurities it is usually disqualified from this title.
Hydrostatic Head: The distance a volume of water has to fall in order to generate power.
Intermittent Energy Source: Any source of energy that is not continuously available due to a factor that is outside of direct control (ex. Wind speed or sunshine).
An internal combustion engine operates by burning its fuel inside the engine, rather than outside of it, as an external, or steam engine does. The most common internal combustion engine type is gasoline powered, followed by diesel, hydrogen, methane, and propane. Engines typically require adaptations (like adjusting the air/fuel ratio) to run on a different kind of fuel than they were designed for. Four-stroke internal combustion engines (each stroke marks a step in the combustion cycle) dominate the automotive and industrial realm today.
Kinetic Energy: The ability of water falling from a dam to do work, that is, to generate electricity. Water stored above a dam has potential energy which turns to kinetic energy once it begins to fall.
Levelized Cost of Electricity: The cost of generating electricity (capital, operation and maintenance costs). Measured in units of currency per unit of electricity (ex. kWh).
Magnetic Survey: A technique for measuring the intensity of magnetic fields from several stations.
Manhattan Project: The massive Anglo-American-Canadian scientific undertaking which produced the atomic bombs that helped end the Second World War. It marked the birth of the nuclear age and scientists were immediately aware of the potential to use use nuclear power for civilian use.
Market Penetration: The share of the total energy market a specific energy source has in relation to its competitors. So the market penetration of wind power would be measured by its share of the electricity market, while ethanol would be compared to other vehicle fuels, not to total primary energy use.
Matrix: In geology, this is the finer mass of tiny sediments in which larger sediments are embedded.
Methanol: Methanol is produced naturally in the anaerobic metabolism of many types of bacteria, and is ubiquitous in the environment. Methanol is toxic in humans if ingested or contacted on the skin. For its toxic properties and close boiling point with ethanol, that it is used as a denaturant for ethanol.
Miscanthus: A low maintenance perennial grass which is thought to be twice as productive as switch grass as it has a longer growing season, greater leaf area, and higher carbon storage per unit of leaf area.
MMBtu: A unit of measurement which means a million Btus (British thermal units). A Btu is roughly the amount of energy it takes to heat a half kilogram of water from 3.8 to 4.4 °C. MBtu is used for a thousand Btus.
Moderator: A moderator is used to slow down neutrons, which enables them to react with the atoms in the nuclear fuel. If enough atoms react then the reactor can sustain a nuclear chain reaction.
M Mount St. Helens is an active volcano located in Washington state. It is most famous for its catastrophic eruption on May 18, 1980 where fifty-seven people were killed, 250 homes, 47 bridges, 24 km of railways, and 298 km of highway were destroyed.
Mud-Pools: Pools of bubbling mud. Also known as "paint-pots" when the slurry of usually grey mud is streaked with red or pink spots from iron compounds.
Nacelle: The housing atop a wind turbine that holds the gearbox, generator, drive train and brakes, as well as the rotors.
Name-Plate Capacity: The intended full-load sustained output of a power plant. For example an average wind turbine's name-plate capacity is 2 Megawatts. The capacity factor is the actual output, so for that 2 MW wind turbine with an efficiency of around 30-35% (average) then it has a more realistic capacity of around 0.7 MW. Most power stations are listed in terms of their nameplate capacity.
National Energy Board: A regulatory agency established by the federal government in 1959 that is primarily tasked with regulating oil and gas pipelines that cross provincial and national borders.
National Energy Program: A set of policies enacted in 1980 that sought to make Canada energy independent. Petro-Canada was created and oil prices were kept artificially low to protect consumers. Shares of oil revenue were diverted to the federal government who used them mostly in the eastern provinces to offset a decline in manufacturing. The program was extremely unpopular in western Canada and was discontinued shortly thereafter.
Nuclear Renaissance: A term used by politicians and the media for the renewed interest in nuclear energy in the past decade. Many countries are now expanding their civilian nuclear programs.
Octane: The octane rating of a fuel is indicated on the pump – using numbers such as 87, 90, 91 etc. The higher the number, the greater the octane rating of the gasoline.
Oil in Place: The total hydrocarbon (oil and gas) content of a reservoir. Sometimes called STOOIP or Stock Tank Original Oil In Place.
Oil Patch: A term for the Canadian oil industry. This specifically means the upstream operations that find and extract oil and gas, mostly in Alberta but also B.C., the other prairie provinces, Newfoundland and Labrador.
Oil Window: The range of temperature at which oil forms. Below a certain temperature and kerogen will never progress to the form of oil. Too high and natural gas is formed instead.
OECD: The Organization for Economic Co-operation and Development is a 34 country organization dedicated to advocating democracy and the market economy. Membership is largely limited to Western Europe, North America, Australia and Japan, what are often considered the world's developed nations. Sometimes referred to in the media as the "rich countries' club".
Passive Seismic Survey: A way to detect oil and gas by measuring the Earths natural low frequency movements.
Peak Power Demand: Power demand varies over minutes, hours, days and months. Peak power demand are the times when the most people are using the most power. To meet this demand extra sources of power must be switched on. Some forms of electricity generation, such as natural gas turbines, can be turned on quickly to meet peak power demand and are better suited for this purpose than others, such as nuclear, which are better as sources of baseload power.
Permeability: A measure of the ability of a porous rock to allow fluids to pass through it. High permeability in the surrounding rocks is needed for the formation of gas reserves.
Photovoltaic Cell: A non-mechanical device typically fabricated from silicon alloys that generates electricity from direct sunlight.
Pickens Plan: Investment of $1 trillion into wind power in the U.S.A., named for an American oil tycoon. The plan aims to reduce the amount of foreign oil imported to the U.S.A. while providing economic and environmental benefits.
Pondage: The main difference between small and large hydro projects is the existence of stored power in the form of water which is held back by dams at large hydro stations. Some small hydro projects have pondage, however, which are small ponds behind the weir of a dam which can store water for up to a week.
Potential Energy: The energy stored in a body or a system.
Porosity: Closely related to permeability, this is a measure of the amount of "voids," or empty space in a rock where gas or oil can pass through to collect in a reservoir.
Possible Reserves: Possible reserves are a class of unproven reserves that geologists use for oil that they are only 10% sure is present in the ground.
Purchasing Power Agreement: A contract between two parties, one who generates power for sale, and another who is looking to purchase it. B.C. Hydro buys power from companies that build their own power generating stations.
Primary Battery: A primary battery is one that is non-rechargable because the electrochemical reaction goes only one way. It gives out energy and cannot be reversed.
Primary Gas: The degeneration of decayed organic matter directly into gas through a process called "thermal cracking." This is opposed to secondary gas which is formed from decayed oil that has already formed.
Probable Reserves: Probable reserves are a class of unproven reserves that geologists use for oil or gas that they are at least 50% sure is actually present.
Proven Reserves: An amount of a resource any resource to be dug out of the ground (oil, coal, natural gas or uranium in energy terms) that geologists have a 90% or higher certainty can be extracted for a commercial gain with the technology available at the time."
Recompleted: The process, by which an old oil well is redrilled, fractured, or has some other technology applied to improve the amount of oil recovered.
Reforming: In oil refining, reforming is using heat to break down, or crack, hydrocarbon atoms and increase their octane level. This technique creates some left-over hydrogen which can be collected and used.
Renewable Portfolio Standard (RPS): Law that requires electric utilities to produce some portion of their power from renewable sources like wind, solar, geothermal or biomass. RPSs are necessary to keep renewables competitive in an era of cheap natural gas electricity.
Rent-Seeking: The practice of using resources to compete for existing wealth rather than to create new wealth, often to the detriment of those who seek to reform societies or institutions. Economies that fail to diversify away from oil are often pre-dominated by a rent-seeking mind-set where people become more pre-occupied with securing the windfall resouce profits for themselves, usually oil, rather than seeking to develop new industries.
Reserves: The fraction of the oil in place that can be considered extractable. This depends not only on the geology, but the economics (is oil expensive enough to make extracting it profitable?) and technology.
Reserve Growth: When an oil or gas field is first discovered, reserve estimates tend to be low. The estimates of the size of the field are expected to grow over time and this is called reserves growth.
Ring of Fire: The Pacific Ring of Fire is a region of high volcanic and seismic activity that surrounds the majority of the Pacific Ocean. This region is essentially a horseshoe of geologic activity, characterized by volcanoes, earthquakes, deep sea trenches, and major fault zones.
Riparian: The term riparian refers to the wetland area surrounding rivers or streams. A riparian ecosystem refers to the biological community supported by an area around a river.
Savonius Turbine: Uses drag generated by the wind hitting the cup, like aerofoils, to create rotation.
Second Generation Wind Turbine: Technology that is only now beginning to enter the market as a result of research, development and demonstration. These are: solar, wind, tidal, advanced geothermal and modern bioenergy. Much hope has been placed upon these technologies but they still provide only a fraction of our energy.
Secondary Battery: Rechargable batteries are sometimes known as secondary batteries because their electro-chemical reactions can be reversed.
Secondary Gas: When oil is subjected to so much heat and pressure it degenerates into gas. The process through which this happens called "thermal cracking."
Secondary Recovery Schemes: When so much oil has been sucked out of an oil reservoir it will lose pressure and the oil will no longer flow out of the reservoir from natural pressure. When this happens secondary recovery schemes can be employed. This means that fluids or gases are pumped into the well to increase pressure and push the remaining oil up out of the well.
Shale: A type of sedimentary rock with low permeability, which was once thought to prevent any commercial extraction of the gas inside. Fracking allows gas developers to access it.
Sound Navigation and Ranging (SONAR): Initially devised as a technique for detecting submarines. An emitter sends off pulses of sound. The pulses bounce off objects and return to a receiver which interprets their size and distance.
Spot Market: A market where commodities are traded for immediate delivery. A future market on the other hand is one where delivery is expected later on. Because of the dependence of gas users on those who are at the other end of the gas pipeline, the natural gas market is mostly a futures market.
Steam Coal: Steam coal is coal used for power generation in thermal power plants. This is typically coal that ranges in quality from sub-bituminous to bituminous.
Straight Vegetable Oil (SVO): Vegetable oil fuel. Most diesel engine vehicles can run on it so long as the viscosity of the oil is lowered enough for complete combustion. Failure to do this can damage the engine. SVO is also known as pure plant oil or PPO.
Strategic Petroleum Reserve: An emergency store of oil maintained by some governments and corporations. The U.S. Department of Energy holds 727 million barrels of oil.
Subcritical Power Plant: A coal-fired power plant that operates at less than 550ËšC. Because the temperatures and pressures are than other plants, these plants operate at a low efficiency, around 33-35%. These plants are still the most common in the world and many are under construction
Supercritical Power Plant: Supercritical plants are coal powered power plants that can sustain temperatures of 550ËšC to 590ËšC and transfer up to 40% of the coals energy into power. This technology has only come into use in recent years. Most new coal-fired power plants built in the West are supercritical.
Switchgrass: One of the dominant native species of the North American prairies, tallgrass is being researched as a renewable bioenergy crop. It is a a native perennial warm season grass with the ability to produce moderate to high yields on marginal farmlands.
Thermal Power Plant: A thermal power plant is any that is powered by a steam turbine. The steam is created by heating water which in turn spins the turbine. Most coal and gas power stations operate in this way, as do all nuclear plants. Coal powered and gas plants are often just called thermal plants.
Total Carbon Cost: The amount of carbon dioxide emitted during an action or a process. One exmaple is building a natural gas plant. The total carbon cost would include everything from the carbon emitted to get the materials to build the plant, to the carbon emitted in the building of the plant, and the carbon emitted during the operation of the plant.
Unconventional Gas: Unconventional gas reserves come in many different geological formations, and include tight gas, shale gas, coalbed methane and methane hydrates. Extraction of these sources has only just begun and has hugely extended the lives of many gas fields and unlocking many new ones. The unlocking of unconventional gas reserves in the last five years has revolutionized the global energy system.
Ultracritical Power Plant: These are coal thermal power plants that operate above 590ËšC and can attain efficiencies above 40%. These plants are just coming into service.
Undiscovered Reserves: The amount of oil and gas estimated to exist in unexplored areas. Much of B.C. has not been thoroughly explored for fossil fuel potential and many of the estimates of B.C. fossil fuel resources rely on the concept of undiscovered resources
United States Geological Survey (USGS): The United States Geological Survey. The department responsible for estimating American fossil fuel reserves. They also conduct many studies that span the globe.
Unproven Reserves: Oil reserves in the ground that petroleum geologists are less certain are there, but have strong reason to believe is present. Unproven reserves can be broken down into probable reserves and possible reserves. These numbers are used within oil companies but not usually published.
The portion of the oil business that involves finding oil and extracting it.
Uranium is a heavy metal that is naturally radioactive. An isotope, U-235 can be enriched to support a nuclear chain reaction. Uranium is used in many nuclear power plants.
A 2,730 MW dam built in north-eastern British Columbia along the Peace River during the 1960s.
Any activity where humans bore down into the Earth to access reserves of oil or gas trapped in underground geological formations.
These are produced from wood residue (like sawdust) collected from sawmills and wood product manufacturers. Heat and pressure are used to transform wood residue into pellets without chemical additives, binders or glue. The pellets can be used in stoves and boilers.
A remote mountain in Western Nevada where the U.S. Department of Energy has planned on storing all of the country's spent nuclear fuel underground since the 1990s. The proposal met stiff opposition from local residents and in 2009 the project was cancelled.