Hydrodynamic Power Offers Abundant Small-Scale Water Power Options

Flowing water carries more than 800 times as much energy as a comparable volume of air, which makes water power an appealing method for producing electricity. Even before the advent of electricity, water mills were some of the earliest systems that went beyond human- or animal-power to do work. In the electrical age, hydropower has typically been associated with big dams and correspondingly large infrastructures. Capturing the power of enormous volumes of water behind a dam allows hydropower stations to produce billions of killowatt-hours of electricity annually, comparable to other base load power plants. But like other base load plants, there is also a strong downside to big dams that makes them less than environmentally preferable. However, new hydrodynamic systems are coming along that draw power from moving water and are able to produce energy with far less environmental impact.

While pent up artificial lakes are easy to turn into massive power plants, the environmental devastation that comes from the flooding of millions of acres of land, and the disruption of the ecosystem of the river make large-scale hydropower a second-class form of green power, at best. From a carbon perspective, hydropower is certainly preferable to burning fossil fuels. But the associated damages caused by building large-scale hydropower plants — including turning flowing water into lakes and blocking the migration of fish — is such that new dams for generating electrical power are mostly off the table.There are alternatives to creating an enormous lake in order to constantly feed the turbines.

Small-scale turbines that can sit in flowing bodies of water and generate electricity could now be poised to bring a new face to hydropower. These turbines are greener since they don’t require the blockage of waterways and the destruction and flooding of land in order to be able to produce power. Hydrodynamic power works with the energy in moving water, rather than closing off waterways to build up huge reserves of potential energy stored in the water held behind giant dams. Developmental systems from several companies are now exploring the production of more modest amounts of power, but with far lower cost and with much less environmental destruction than that from the creation of dammed hydropower. Companies such as Hydrovolts Inc., Free Flow Power and Verdant Power have different systems to make use of this power, which they are testing in different parts of the country. There are also researchers who are working on other systems that can potentially take advantage of more energy available in slower moving water.

The federal government in the United States has identified this as an as-yet untapped source of power. The existing water infrastructure of the American West offers a great deal of hydropower potential, with the greatest amount found in the states of Colorado, Oregon and Wyoming. A study by the U.S. Department of the Interior’s Bureau of Reclamation found that 1.5 million megawatt-hours of renewable energy could be generated through hydropower without needing to construct new — and environmentally questionable — large-scale dams. Instead, existing waterways and reservoirs can be used to provide electricity in addition to serving water needs of the region. (For comparison, the Hoover Dam power station produces about 4 million megawatt-hours of electricity annually. Think of this as another one-third of a Hoover Dam spread out through the existing water infrastructure.)

Aqueducts and canals represent an available source of power for additional electrical generation. Particularly in the western U.S., where water management is carried out through an extensive infrastructure of constructed canals and waterways, it may be possible to provide power for tens of thousands of additional homes. Existing dams that were built for water management rather than for power generation may be able to be tapped for power production as well, through the installation of smaller scale equipment that can efficiently and cost-effectively produce power from dams that may have previously been thought too small to be useful for power generation.

To make use of this hydrodynamic power, small, in-line turbines can be installed that generate electricity from the flow of water through aqueducts and canals. The turbine sits directly in the waterway, without a dam, which means that the negative impacts to the environment, as well as the infrastructure costs to install this equipment, are greatly reduced.

Because these waterways already constrict the flow of water moving through them, a greater proportion of the energy from the water flow can be captured with this equipment. In a canal, where most of the water flow must go through the turbine, the efficiency can be as high as 60 percent. Depending on the size of the waterway and the flow rate of the water moving through it, turbines can provide electrical output ranging from 1.5 kW to 30 kW. Because many of these waterways have continuous flows of water moving through them, they are well suited to provide additional, continuous power generation for the grid.

The Bureau of Reclamation has over 47,000 miles of canals, laterals, drains, pipelines and tunnels. To find places with hydropower potential, the government study identified those locations where there was at least a 5-foot drop and where the waterway was in operation for at least four months out of the year and where the power generation potential was at least 50 kW (based upon flow rate of canal and the drop height).

One manufacturer producing turbines for in-line uses is Hydrovolts, Inc. These are reasonably small pieces of equipment. Turbines for canals and waterways are about the size of a car or small truck. Waterfall turbines can be even smaller, and will still produce a significant amount of power. They are also fairly inexpensive, with the cost of the smallest portable model starting at just $2,000. The canal-sized turbines cost from $20,000 to $40,000. While wholesale electrical rates are not great, since their output will be fairly consistent, these turbines can potentially repay their investment cost in just a few years. Initial tests of the Hydrovolts turbine were carried out in the Roza Canal in Washington State earlier this year.

(Quick back-of-the-napkin math: A turbine costing $40,000 and generating an average of 25kW over a year of operation will produce almost 220 MWh of power and earn over $10,000 at a wholesale electrical rate of $0.05/kWh. That could mean that the equipment could be paid off in four years.)

Hydrovolts turbine in the Roza Canal in Washington State:

Hydrovolts turbines also can be outfitted with different kinds of blades, depending on the flow rate of the water. This makes the system more versatile, and the same equipment can be used in different locations, with just a change of blades in order to produce the optimal yield from a given location.

While many of these channels being discussed for use are artificial waterways used for irrigation, the same technology can be used in open water rivers and streams with a sufficient flow rate. In those cases, having the waterway open to fish migration and movement is another benefit from this technology.

While the Hydrovolts turbines are being developed for very small waterways, the opposite end of the hydrokinetic power scale is also being explored with a project set in the world’s largest river. Free Flow Power is a company that is developing river flow turbines to be placed along a length of the lower part of the Mississippi River.

The Free Flow Power turbine is a 3-meter diameter multi-bladed propeller inside a housing that makes it look very much like a large jet engine. The turbine has a 40 kW rating. The first array of these turbines will be installed at a total of 25 locations along the Mississippi River and will provide a total generating capacity of 3,303 MW. Given the size of the river and the volume of water that flows through it, there is a great potential for much more energy production if this technology turns out to be effective and cost-competitive.

Unlike wind farms, these turbines are out of sight below the surface of the water. Despite their size, since these turbines will be installed below the water’s surface, they will present very little obstacle to navigation, so that the Mississippi will also continue to serve as an efficient highway for barge traffic moving goods up and down the river. This project may be just the beginning for harnessing the vast power of so much water moving through the middle of the country.

In New York City’s East River, the Roosevelt Island Tidal Energy Project (RITE) being run by Verdant Power Inc. will eventually have 30 turbines installed underwater and generating as much as 1,050 kW of electricity when the pilot project is fully installed in 2015. These turbines are considerably larger than the Hydrovolts equipment. Rather than drawing power from the narrow flow of water in a channel, these units are instead powered by the tidal flows from the ocean.

Verdant Power has another project that builds on some of the work done for the RITE project. The Cornwall Ontario River Energy Project (CORE) is installing turbines in the St. Lawrence River near Cornwall, Ontario to study how the turbines work in a river flow situation.

The turbines Verdant is developing are three-bladed, without an enclosure, and look quite similar to the now familiar three-bladed wind turbines, except for their comparatively much smaller size. The Verdant turbines are larger than those being developed by Free Flow Power; for the CORE project they are using turbines with a blade diameter of 5 meters and with a generating capacity of 60-80 kilowatts. These turbines, too, would sit out of the way of surface vessels on the bottom of the waterway. An animation from Verdant shows what a large-scale farm of these turbines might look like.

Along with these developmental systems, researchers are working on other low-velocity technologies for hydrokinetic power generation. One system, being explored by researchers at the University of Michigan is called VIVACE, which stands for Vortex Induced Vibrations for Aquatic Clean Energy. VIVACE is especially interesting because it promises to work with slow moving river flows as slow as 2 knots. Most river currents in the United States are slower than 3 knots.

The VIVACE system works with horizontal cylinders placed across the flow of the water to create a vortex as the water flows past the cylinder. “Vortex Induced Vibration (VIV) is an extensively studied phenomenon where vortices are formed and shed on the downstream side of bluff bodies (rounded objects) in a fluid current. The vortex shedding alternates from one side of a body to the other, thereby creating a pressure imbalance resulting in an oscillatory lift.” This motion of the cylinder can, in turn, be used to move a magnetic field in order to produce electricity.

The turning blades of hydrokinetic turbines are a potential concern, just as wind turbines are with birds. Part of the reporting being done with these early projects is to study potential problems with this kind of equipment. Although its development is lagging behind some of the other systems, VIVACE may turn out to be a preferable technology because it has less impact on marine wildlife. The cylinders used in this system are very slow moving (only about 1 cycle per second), and the risk of harm to any fish is therefore extremely low.

Hydrokinetic projects are appealing because the power generation is more constant than some other sustainable systems. Waterway flows can be more regular and dependable than intermittent sources like wind. Hydrokinetic power is presently an underutilized resource, but as these companies develop their technology, it is likely to become another part of the energy mix.

By Philip Proefrock@REVMODO.com



 

Hydropower Continues Steady Growth

World hydroelectric power generation has risen steadily by an average 3 percent annually over the past four decades. In 2011, at 3,500 billion kilowatt-hours, hydroelectricity accounted for roughly 16 percent of global electricity generation, almost all produced by the world’s 45,000-plus large dams. Today hydropower is generated in over 160 countries.

© Earth Policy Institute

Four countries dominate the hydropower landscape: China, Brazil, Canada, and the United States. Together they produce more than half of the world’s hydroelectricity.

© Earth Policy Institute

Much of the world’s recent growth came from China, where hydropower generation more than tripled from 220 billion kilowatt-hours in 2000 to 720 billion in 2010. In 2011, despite a drop in generation due to drought, hydropower accounted for 15 percent of China’s total electricity generation.

© Earth Policy Institute

Brazil, the second-largest producer of hydropower worldwide, gets 86 percent of its electricity from water resources. It is home to an estimated 450 dams, including the Itaipu Dam, which generates more electricity than any other hydropower facility in the world—-over 92 billion kilowatt-hours per year.

Approximately 62 percent of Canada’s electricity is generated from its 475 hydroelectric plants. The country’s enormous hydropower capacity allows for electricity export; Canada sells some 50 billion kilowatt-hours to the United States every year—-enough to power more than 4 million American homes.

Because most large dams in the United States were built before 1980, the country’s hydropower capacity has remained relatively stable in recent decades. The country’s highest capacity dam—-the Grand Coulee Dam on the Columbia River in Washington State—-was completed in 1942. Today, more than 7 percent of all U.S. electricity is supplied by hydropower. Similarly, hydropower in the European Union is relatively mature, with capacity increasing by less than one percent annually over the last 30 years. In 2011, hydropower supplied 9.5 percent of E.U. electricity generation.

© Earth Policy Institute

Among the world’s largest producers, Norway gets the greatest share of its electricity from hydropower: a full 95 percent. Other countries that get the bulk of their electricity from river power include Paraguay (100 percent), Ethiopia (88 percent), and Venezuela (68 percent). A number of African and small Asian countries also generate virtually all of their electricity with hydropower, including Bhutan, the Democratic Republic of the Congo, Lesotho, Mozambique, Nepal, and Zambia.

© Earth Policy Institute

While conventional hydropower will continue to grow as dams are completed in China, Brazil and a scattering of other countries, including Ethiopia, Malaysia, and Turkey, there exists enormous potential for non-conventional hydroelectricity generation from tidal and wave projects, as well as from small in-stream projects that will not require new dams.

Thus far, few of these hydrokinetic projects have been realized. France’s La Rance Tidal Barrage, with a 240-megawatt maximum capacity, was the first large tidal power plant. It began generating power in 1966, and is still operating today. In South Korea, a 254-megawatt project was completed in August 2011. Now the world’s largest tidal operation, it has the capacity to provide electricity for half a million people on the country’s west coast. New Zealand also recently approved a coastal hydropower project.

Wave power is also drawing the attention of both engineers and investors. Firms in France, Scotland, and Sweden, among other countries, are working to capture this emerging market. Estimates from the World Energy Council indicate that worldwide, wave energy has the potential to grow to a massive 10,000 gigawatts, more than double the world’s electricity-generating capacity from all sources today.

For additional data on the world’s energy resources, visit Earth Policy Institute’s Data Center and see the Supporting Data from World on the Edge by Lester R. Brown at www.earth-policy.org.

By Lester Brown@ treehugger.com 

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Kashmiris Fear Hydro Scheme Could Leave City High and Dry

Residents and environmental experts in Muzaffarabad, Pakistani-administrated Kashmir’s main city, fear the diversion of a major river to generate hydroelectric power will deprive local people of water for drinking and waste disposal, and could alter the region’s climate.

The Neelum River gushes down into Muzaffarabad from the Indian-controlled part of the disputed Himalayan territory, running through the middle of the city. It transports away urban sewage discharged into it and provides the inhabitants’ water supply.

But Pakistan’s largest hydropower project of recent decades threatens to lower the river level, leaving too little water to deliver those vital services.

“How we can live here if this river is reduced to a stream with sewage abandoned on its bank?” asks Shoukat Nawaz Mir, who owns a three-storey house on the banks of the Neelum River.

“It has been difficult to be here for a while now due to the stink, as there is no proper system for disposing of sewage and other waste, which is lying around in the open. And it will be a nightmare to live here when there is less water in the river,” says the 38-year-old, pointing to the fast- flowing channel. 

“I have spent most of my life here, but I fear for how my children will live on the bank of an almost dry river. There should be compliance with environmental protection law,” he says wistfully.

Some 32 km of tunnels are being dug out, into which 86 percent of the river’s water will be diverted. When completed in 2016, the water will be used to produce cheaper electricity in a large hydropower scheme with installed capacity of 969 megawatts.

The diverted river water will be discharged into the Jhelum River 28 km south of Muzaffarabad.

ENERGY CRISIS

The work is being carried out on a tight schedule, partly to overcome a severe energy crisis in Pakistan. Extensive power cuts fuelled violent protests in Punjab last month.

A report from the Asian Development Bank, released in April, said power shortages are the main constraint on Pakistan’s economic growth, as domestic resources of hydro, gas and coal have not grown enough to cover energy demand, increasing its reliance on imported fuel oil.

In addition to providing much-needed power and reducing imports of costly and polluting fossil fuels, the new hydro scheme is also regarded as an attempt to secure rights over Kashmir water.

Arch-rival India is also building a dam on the same river in its part of Kashmir, which could curb downstream power generation capacity by 13 percent once finished, due to reduced water flow, according to Muhammad Zubair, head of the Neelum Jhelum Hydro-Power Company.

The long-running dispute between the two countries over the territory of Kashmir extends to water, despite a treaty agreed in 1960 that defines rights to the rivers flowing into Pakistan from India.

The World Bank-mediated Indus Water Treaty (IWT) is intended to resolve disputes over waters originating in the Indus Basin. It allocates the waters of rivers in the eastern basin – the Sutlej, Beas and Ravi – to India, while Pakistan has unrestricted use of the western rivers – the Indus, Jhelum (of which the Neelum is a tributary) and Chenab.

After India began constructing the Kishanganga dam on the Neelum, arguing that the water would ultimately be returned to the river and flow into Pakistan, Pakistan filed a complaint with the Permanent Court of Arbitration at The Hague in 2010. The court issued a stay order on the work last year, saying the project may not comply with the IWT.

But the problems with hydropower projects on Kashmir’s rivers are not just political.

ENVIRONMENTAL FEARS

Concerns have been raised in Pakistani-administered Kashmir’s legislative assembly about the environmental impacts of the Muzaffarabad project, with legislators demanding the publication of the agreement between the local government and the company managing the scheme.

A separate proposed hydropower scheme on the Jhelum River - which would have involved diverting 90 percent of its water – was refused authorisation.

Irshad Qureshi, director-general of the Kashmir Environment Protection Agency (EPA), told AlertNet that government permission was issued for the Neelum project on the condition that its backer, the Pakistan Water and Power Development Authority (WAPDA), complies with national environment quality standards.  

The approved project, now underway, plans to divert an average of 280 cubic metres per second (cumecs) of water from the 322 cumecs that flows in the river’s peak season from April to September, when it is fed by snow and glacier melt. In the winter, between October and February, the water flow falls to just 59.9 cumecs, according to Qureshi.

Diverting the river “will have a serious impact on the environment”, he noted, as there will be less water for drinking supplies and washing away waste. The temperature in the local area could also increase because the cooling effect of the river will be curbed due to less evaporation, he warned.

A dam, 60 m high and 160 m long, is being built to raise the water to the required level during the winter, and a 9-km-long lake is being created to act as a reservoir.

Six sewage treatment plants and an expanded water supply scheme will also be installed to improve the provision of drinking water to urban areas, Qureshi added.

Nonetheless, environmentalist Sahibzada Aftab Alam also believes that diverting the river could affect the Himalayan climate, leading to higher summer temperatures.

“Disturbing the natural flow has a major impact on the climate of the area as it affects aquatic life, the water table and the spring-recharging process, as well as drinking water quality and quantity,” he explained.

Most of Kashmir’s population lives in rural areas, depending largely on forestry, livestock and agriculture for their livelihoods. River water and natural springs are the main source of drinking water and irrigation – and these will be affected by “serious water shortages” caused by the power scheme, Alam argues.

“The project area, 40 km away from the city, has significant conservational importance due to an abundance of forests, aquatic life and many species of wildlife, which have been declared endangered globally,” he said.

The aesthetic beauty of the city and its surrounding areas, which attract tourists, could also be damaged, he warned.

ECONOMIC DEVELOPMENT

Muhammad Shafique Abbasi, an environmentalist working with the EPA, worries about what will happen once the hydropower scheme is up and running.

“They will definitely not care about environmental concerns once they complete the project, and this is about what we are anxious about,” he said.

“What will the situation be when there is only 60 cumecs of water in the river during the lean season in winter, while 280 cumecs will be required for (power) generation?” he questioned.

But Mavish Durrani, another EPA expert, argues that the hydropower project could also have some positive effects - for example, the new dam and reservoir could enhance local rainfall due to evaporation and condensation of the water they contain.

“They will attract migratory birds to the area and improve aquatic life and forest growth, besides the working of water cycle,” he said. 

Zubair of the Neelum Jhelum Hydro-Power Company, a subsidiary of the WAPDA, told AlertNet that enough water will be provided from the dam to guarantee local water supplies.

In winter, when the river flow is at its lowest, the company plans to release around five times the daily amount required to meet Muzaffarabad’s sewage treatment and drinking water needs to maintain the city’s environment, he said.

“The environmental concerns are small when compared with energy generation of more than 5.1 billion electricity units annually - which means income of around 45 billion rupees ($0.5 billion) to the government each year, besides economic development for the people of the area,” Zubair added.

Written by Roshan Din Shad a freelance journalist based in Muzaffarabad@AlertNet

Hydropower: India

The nearly 150 dams planned for the sparsely populated state of Arunachal Pradesh would together fill India's current energy gap. But they will also devastate dozens of indigenous tribal peoples, wipe out thousands of acres of breathtaking forest and do away with some of the world's best whitewater. 

visual.ly 

Water Power: Out with the New, In with the Old by Zachary Shahan

Solar and wind energy are well-known renewable energy options that are quickly growing in use around the world. Both have seen record-breaking growth in the past few years. Tremendous growth is projected to continue in the years to come, as well. But solar and wind won’t provide the world with all of its energy needs. They may not be ideal for some locations, and they may need to be supplemented by other energy sources in some locations.

Other than the ubiquitous wind and the tremendously powerful sun, one of the most abundant natural resources on our planet is water, and flowing water carries a great deal of energy. Just think of the feeling you had when you walked into a medium- or fast-flowing river or stream, or decided to test your strength against a breaking wave.

While wave power, tidal power, ocean thermal power, and other “water power” options exist, this article only discusses the most readily available water power option today — small or micro hydro.

Small Water Power (or Micro Hydro) Potential

New micro hydro (aka microhydro or micro-hydro) could produce 30,000 megawatts of decentralized, local power in the U.S. alone, according to a 2006 study. To put that into perspective, that’s enough power for up to about 30 million homes.

“We keep telling lawmakers that there’s tremendous growth potential in the industry. We are far from tapped out,” Jeff Leahey, director of government affairs for the National Hydropower Association, says. “We can access existing infrastructure today and build tens of thousands of megawatts in communities around the country.”

The map below shows what percentage of a state’s electricity sales could be provided from new micro hydro.

All of this small hydro potential could be tapped with “run-of-river” projects (projects not requiring dams) or projects that make use of existing dams.

“There are over 81,000 dams around the U.S. and only 2,400 of them have any electrical generating capacity,” Stephen Lacey of Climate Progress reports. “Many of the power-less 78,600 dams are close to existing infrastructure, making it easier to build and maintain a project compared with a centralized wind or solar farm located far away from where the electricity is used.”

The question, however, is what technology will be able to capture that energy and efficiently turn it into electricity for a home, business, or community.

continue @ cleantechnica.com 

US Plans its First Megadam in 40 Years by Fred Pearce

It reads like a fairy tale from the brothers Grimm: a giant US state is planning a giant hydroelectric dam that could flood a tiny shrew out of its idyllic home.

Later this month, Alaskan authorities will file plans in Washington DC for a 213-metre megadam on one of the country's last remaining wild rivers: the Susitna. If approved, it would be the country's first hydroelectric megadam for 40 years, and its fifth tallest, just 8 metres shy of the Hoover dam.

Opponents say the project is a $4.5 billion boondoggle that will affect wildlife including caribou, grizzly bears and salmon. Instead they say the state should tap its abundant tidal, geothermal and wind power.

But the icon for protest against the dam may turn out to be the country's most secretive shrew. Weighing in at just 1.5 grams, Sorex yukonicus lives on a bank 10 kilometres downstream of the proposed site for the dam.

In 1995, Daniel Beard, head of the US Bureau of Reclamation, the nation's main constructor of dams, declared the US dam-building era over. He cited growing environmental concerns. Dozens of dams have since been torn down to revive fisheries and reinstate river habitats.

But after years in the environmental doghouse, large dams are being promoted as a source of low-carbon energy, and the 600-megawatt Susitna project looks like it could be the first to get the green light.
Read more @ NewScientist.com

                            

EarthTechling recently sat down with Hydrovolts Founder and CEO Burt Hamner at Hydrovolts’ offic.

Hamner first got the idea for Hydrovolts while working on a feasibility study for a proposed tidal power plant in the Tacoma Narrows region of Puget Sound in 2007. Ultimately, the report concluded that a commercial tidal power plant was not technically or economically feasible. But, the study did inspire Hamner to explore the possibility of generating power in smaller, artificial water channels. Unlike Puget Sound, “these canals generally have steady, predictable currents, contain little or no debris, have no endangered species, and are easily accessible by road,” he said. “They are also typically maintained by large engineering organizations that know how to handle machinery.”

Hydrovolts was born from Hamner’s desire to develop a “plug and play”, drop-in micro-hydro turbine that requires no concrete or construction, and utilizes commercial off-the-shelf components. The turbine features a “flipwing” rotor, which uses hinged blades to rotate the center turbine shaft. As the blades begin their reverse upstream stroke, they flip open backwards to eliminate resistance (see video above).

Read more: 

Wave energy is produced when electricity generators are placed on the surface of the ocean. The energy provided is most often used in desalination plants, power plants and water pumps. Energy output is determined by wave height, wave speed, wavelength, and water density. To date there are only a handful of experimental wave generator plants in operation around the world. The articles on this page explore the world of wave energy and its possible applications. 
Read more about Wave Power