By Charlotte Helston
Many countries are now utilizing hydropower, including both developed and developing nations. For the developed world, it offers the opportunity to shift to renewable resources. For developing nations, and for those areas still without electricity, it presents the chance to skip over the non-renewable phase, and opt instead for a first electricity source that has the potential to be clean and inexpensive. Of course, it is only viable for countries that feature the required climate and geography to house hydro power. Where it exists today, hydroelectricity represents a renewable energy that, once developed, produces no direct waste and emits very small amounts of greenhouse gases. But, like any energy source, it has its ugly side. Lesser known, or lesser noticed alongside hydropower's many advantages, are the environmental and social impacts also associated with it. The consequences of damming are far-reaching; conversion of surrounding valleys to lakes displaces communities of both humans and animals, and slowed flow-rates can cause severe losses in biodiversity and increases in sedimentation permanently changing that area.
Canada has a century long history with hydropower, and is currently the world's third largest producer. After the industry's initial thrust in the mid to late 20th Century, development stalled in Canada, and North America in general. A combination of expense and a wave of hesitancy due to unaddressed environmental concerns seem to be the main drivers barring expansion. Though Canada is said to have untapped potential double its existing capacity, the environmentally conscious route would be to upgrade old facilities to minimize wilderness disturbance.
Refurbishment plans are popping up across the country, with or without government assistance. In some cases, as with BC Hydro, consumers are paying for the upgrades in increased electricity rates. Currently, 60% of electricity produced in Canada is drawn from hydro. Only a portion of that hydroelectricity is used in Canada; the rest is exported for profit.
There are three different types of river-based hydroelectric facilities; storage, run-of-river and pumped hydro.
Hydroelectric power stations capitalize on the kinetic energy of falling water to produce electricity. Kinetic energy exists in any body of water that flows, by force of gravity, on a downhill slope. The amount of energy that can be generated is related directly to the amount of height change that exists. Though the planet has many naturally occurring hydro power hotspots — like rivers and waterfalls — most power plants manipulate the force of the water with dams. Man-made dams retain massive amounts of water in reservoirs, and form drastic drop-offs that enhance the kinetic energy of falling water. The contained water is used to store energy in the form of
The generator, attached to the turbine via a shaft, contains a series of magnets that spin and move past copper coils forcing the movement of electrons creating
Storage hydropower offers a big advantage over many other energy producers, as it can respond to increases in demand almost immediately by releasing extra water which spins the turbines faster and generates more electricity. Power stations can also quickly bring on additional turbines to meet demand.
Run-of-river facilities employ the natural flow and elevation drop of rivers. An intake structure forces water through a submerged pipeline, or penstock, which leads to a turbine. The turbine drives a generator, which then produces alternating current. Water is directed back to its initial path further down river. In run-of-river systems, the construction of dams — and their associated impacts — are avoided. This system is not without faults as seasonality in precipitation and river flow affect power output. If there is not enough water flowing through the stream to enter the penstock then no power can be produced. The lack of a reservoir causes this type of system to be unreliable for large scale power output. Long-term small scale power output can also be unreliable due to instabilities in climates. A separate article closely analyzing run-of-river power can be found here.
Pumped hydro is a combination technology incorporating aspects of both run-of-river and conventional storage facilities. It too uses the flow of water to drive turbines, which in turn powers generators. The power station uses normal river flow, but also has a reservoir located upstream of the facility where water can be pumped and stored. During times of high production, surplus electricity is used to push water upstream to the reservoir or to high alpine lakes to prepare for future periods of high demand.
In Canada there is only one pumped-storage facility, Sir Adam Beck Pump Generating Station at Niagara Falls in Ontario. Built in 1957, the station has an output of 174 MW.
The principle in hydroelectric systems is similar to that of many other energy sources. Many technologies, including coal-fired power plants as well as solar thermal and geothermal plants use steam to drive turbines. Hydroelectric plants use water instead. Once the turbine is spinning and the generator activated, electricity is created.
Hydropower is extremely efficient; most modern stations can convert over 95% of available energy into electricity.
Hydroelectric developments depend upon a combination of elevation, climate and running water. It is most common for hydroelectric power stations to be located on mountain rivers at points where the elevation begins to drop significantly. High precipitation levels are needed to enhance river flow. In North America, hydroelectric plants are typically located on or around major rivers.
Hydroelectric development calls for an alteration of the surrounding landscape. When dams are built to create reservoirs, water floods out over once dry land, and a man-made lake is formed. This new body of water offers recreational opportunities like boating and fishing, however, it also modifies the natural ecosystem, a side-effect that has sparked much debate. Not only does the construction of a dam affect the encircling area, it also affects the river as a habitat for marine creatures.
Hydroelectric power station projects are best undertaken in collaboration with local communities and conservation groups to minimize negative environmental impacts.
Hydropower contributed 15% of total global energy production in 2008, making it the leading source of renewable energy today.
China doubled its capacity between 2004-2009, and now sits as the world's top country for hydroelectric production, with 549 billion kWh generated in 2009. Despite leading the world in hydroelectric power generation (as well as being the world's top investor in renewable energy projects), China still relies on coal for over half of its energy. Brazil, the world's second largest producer, generated 387 billion kWh of hydroelectric power in 2009, followed closely by Canada with 363.4 billion kWh.
With the right planning, considerations, and collaborations, hydropower development can make significant contributions in improving living standards in the developing world. Approximately 1.5 billion people still lack access to electricity.
Canada is the world's third largest producer of hydroelectricity, generating 348.1 billion kWh in 2010.
Unlike all other renewable energies, hydropower has served Canada on a major scale for over a century. The first generation of electricity from hydropower in Canada was at Chaudieres Falls in 1881. The water wheel, built by the Ottawa Electric Light Company, powered street lights and local mills. Large scale development began in earnest in the early 1900s, with sites constructed in at Niagara and Shawnigan. Large stations erected in the 1960s and 70s marked a settling time for expansion, with very few new hydro sites developed into the mid 90s, and almost no new sites as of 2005.
Canada's long history with hydropower has fostered experience and skill in both facility design and construction. Some of the world's largest and most efficient hydropower facilities involved Canadian architects, engineers and builders. Canadian development of hydropower facilities has occurred in Colombia, Ghana, Malaysia, India and the Philippines, among others.
Canada is also the United States' biggest supplier of electricity, alongside oil, natural gas and uranium. In 2009, Canada's energy exports to the U.S were valued at $76.27 billion, with nearly 2/3 of energy accounted for with hydropower.
Quebec accounts for the majority of hydroelectric production in Canada. The eastern province draws 94% of its power from hydroelectric facilities. With a capacity of 34,490 MW in 2010, hydropower supports over four million customers there.
The geography and climate of British Columbia predisposes it to the use of hydropower. BC Hydro, a provincially owned crown corporation, was established to develop large-scale hydro power facilities and to distribute electricity province-wide. BC Hydro operates 30 power plants, and produces more than 43,000 GWh of electricity annually, providing energy for over 1.7 million residential, commercial and industrial customers.
No significant projects have been undertaken since the 1990s, though Canada's position as a net importer of electricity has raised interest in developing new sites, and expanding old ones to become more self-sufficient. Expanding existing facilities seems the least contentious proposition as it avoids disturbance of undeveloped river systems, and constitutes less of an investment. See the Economics section for more information on BC Hydro's development plans.
The hydropower industry dovetails nicely with the government's aim to boost the economy with cheap energy supplies, and meet clean energy goals. As Natural Resources Minister Christian Paradis said in a 2010 speech, "[The] industry employs tens of thousands of people... and makes a significant contribution to Canada's economic growth and prosperity." Prime Minister Stephen Harper has said the industry "not only stimulates economic activity and boosts employment where it is needed today, [but] also provides communities with the infrastructure needed to prosper in the future." The already well-established industry has offered the Canadian government an ideal energy source to support. It comes without the some of the challenges of other renewables like solar, geothermal or wind, and it's been working in Canada for over a century.
Rather than investing to help bring alternatives like solar into the mainstream, the government can invest in the tried-and-true industry of hydropower. Paradis said, "[The Canadian government's] ecoENERGY for Renewable Power program is supporting hydro projects such as the Brilliant Dam expansion project in Castlegar, B.C., and the Centrale hydroélectrique Rivière Magpie project in Rivière Saint-Jean, Quebec." Contributions such as the ~$47 million allotted to the Brilliant Dam over a proposed 10 years, beginning in 2008, will help keep renewable energy at cost competitive prices. The dam's upgraded facility will generate 120 MW of clean electricity, offsetting about 450,000 tonnes of greenhouse gas emissions.
In late March of 2011, during the lead-up to the recent federal election, Stephen Harper announced that a re-elected Conservative government would provide financial support for the Lower Churchill hydroelectric project in Labrador — a $6.2 billion investment.
What has the Canadian government done to address the environmental concerns related to hydroelectric power stations?
Hydroelectric facilities are the culprits in devastating habitat destruction, both during construction and operation. Measures can be taken to reduce the negative impacts. Building code requirements such as fish ladders can help mitigate some of the effects by providing safe routes around turbines that migrating or spawning fish can get trapped in. Some ladder requirements have been put in place, however, they are often ineffectual due to poor placement or too few installations. Additionally, ladders provide no safeguard against other issues such as sedimentation, de-oxygenated water, impoundment, and reduced water flow. An examination of the environmental impacts of hydropower facilities can be found in the Environment section.
Natural Resources Minister Christian Paradis noted in a 2010 speech that the "government is committed to implementing simpler, clearer regulatory processes that will improve environmental protection..." Details on the nature of these new regulations have yet to be released. In addition to funding facility refurbishment, it would be progressive for the Canadian government to phase in environmental protection regulations as soon as possible to prevent damage before it is too late to undo it.
Since its origins in the late 1800s, hydropower has not only powered homes and industries, but the economy as well. In many cases throughout Canada's history, the development of hydropower facilities in remote areas drew people, commerce and other industries, reinforcing itself as a main factor in the creation of towns and cities.
Christian Paradis, Minister of Natural Resources, said in a 2010 speech; "[The hydropower] industry employs tens of thousands of people, such as engineers, geologists, construction workers, electricians and mechanics, and makes a significant contribution to Canada's economic growth and prosperity."
BC Hydro is one of Canada's top 100 employers, providing direct jobs for around 5, 200 employees.
Development costs range depending on the condition of the site, as well as the type of facility being constructed. The main investments center on the engineering, equipment and the turbine. The electrical generator constitutes less than 5% of the total cost of a power plant.
British Columbians enjoy some of the lowest electricity rates in North America. The average four-member household pays about $77 per month. The three provinces (British Columbia, Manitoba and Quebec) that produce the most amount of hydroelectricity have the lowest electricity rates. Provinces that rely highly on fossil fuels tend to have higher electricity rates and prices are much more volatile because of the changing market prices of the fuel needed to run the generators.
BC Hydro, British Columbia's predominant electric utility, charges consumers based on a two tiered system. If daily averages remain less than 22.1918 kWh consumers pay $0.06270 per kWh. Anything above that falls into the next category, which charges $0.08780 per kWh.
BC Hydro has announced cost increases that would bring average monthly bills to $92, from the previous $77. Most of BC's dams are over 50 years old and in need of major upgrades. BC Hydro's plan to raise electricity rates by 10% in each of the next three years, adding $180 onto homeowner bills, and earning the company enough money to upgrade about a dozen dams and generating stations, including the 80-year-old Ruskin Dam which will require an $800 million investment.
What are the land requirements for hydropower?
A single reservoir providing water for a 1,300 MW hydroelectric power plant needs roughly 650 km2, or 50km2 per 100 MW installed. In other words, a space of about 4,629 soccer fields gives way to enough power for 60,000 homes.
How do hydroelectric facilities affect the environment?
Because hydroelectric dams do not burn fossil fuels, they avoid a considerable amount of emissions compared to other energies. Their operation releases no pollutants that cause acid rain and smog. Studies estimate that hydropower prevents the burning of 22 billion gallons of oil, or 120 million tons of coal each year.
For many years hydropower was considered emissions-free, and it wasn't until recently that the energy was included in global emissions reports. Outside of construction, emissions are most noticeable when plants decompose in the flooding caused by a dam, or impoundment zone, and produce methane, a greenhouse gas that is much more powerful than CO2.
The decaying vegetation also contains bacteria that can change the naturally occurring mercury present in rocks, into a form that is soluble in water. Once released in this form, mercury begins to accumulate in the bodies of fish — a health hazard to any creature who consumes them. The Canadian Hydropower Association notes that an estimated 2/3 of mercury found in the environment has its origins in smelters, incinerators, and coal and oil-fired plants. The leftover 1/3 is believed to be naturally occurring, potentially the result of hydro developments.
Another environmental impact arises from the diversion of water from its natural path. Damming causes changes in the replenishment of fresh water, thereby affecting overall ecosystem health.
Damming also slows the flow-rate of all river water, not just within the reservoir.
Additionally, man-made reservoirs, and the water released from them can also cause problems downstream. Often, lake bottom water is inhospitable to fish for two reasons: temperatures are much cooler than they are near the surface, and deep water is oxygen depleted compared with shallower water. When this cold, oxygen poor water is released in massive quantities to create electricity, it can shock fish living downstream in warm, oxygen-rich pools. Surging waters also cause downstream flooding which can carry fish out of the river.
Sedimentation is a long-term problem associated with the damming of a river system. Because the flow rate of the river has been decreased to almost zero, sediment will settle in the reservoir behind the dam. This can lead to storage loss, operational impairment, environmental degradation and recreational impairment.
The effects of hydroelectric development are worst when power station chains — series of stations erected along an extended portion of a river — are created.
Water pollution at the time of construction can occur when construction materials interact with river system. These effects can pose grave consequences, but can be mitigated with appropriate procedures and precautions.
The conversion of land into artificial lakes has consequences for bird populations and other animals. Because of the low power density of hydroelectricity, it takes a lot of land to produce a relatively low amount of power. This directly affects animals including humans. In some countries, it floods former agricultural land, putting stress on the livelihoods of local communities. Recently, more than one million people were relocated in China in order to build the reservoir for the Three Gorges Dam which also included the relocation of two major cities.
The massive amounts of water held back by conventional hydro facilities contain potential energy, as well as potential risks. Failures arising from poor construction, or the age of the facilities, can unleash powerful floods that devastate villages, farmland, and wildlife habitats. The Banqiao Dam failure in China in 1975 killed 26,000 people in the ensuing flood. A further 145,000 people died from epidemics catalyzed by contaminated water. The typhoon that passed over the region was twice as large as the facility had been built to withstand.
Large dams may influence geologic stability and induce seismic activity, though this is only speculative at this point. The earthquake at the Koyna dam in India in 1967, which killed approximately 180 people, is believed by some to have been caused by the Koyna reservoir.
Dams can also be targeted during wars or as by terrorists. The most famous instance of a dam becoming a military target was being Operation Chastise during the Second World War, in which the Royal Air Force bombed three key dams in Germany that provided electrical power, drinking water and water for the canal transport system.
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