Saturday, December 6, 2008

The Most Important Barack Obama Appointee: EPA Administrator Short List

Written by Jennifer Lance

President-Elect Barack Obama will inherit a host of problems from outgoing President Bush. From an economy in recession to the Iraq War, cleaning up from eight years of the worst US president is a immense task. Obama has already selected many former rivals, such as Hilary Clinton, for his cabinet, but the most important appointee he will make is the head of the Environmental Protection Agency (EPA). Although the EPA administrator is not a cabinet level position, this may change as Obama faces the crisis of climate change.

Under the Bush administration, the EPA has loss all credibility as an agency that protects Americans from air and water pollution.
According to the Washington Post,

“…over the past eight years, many career employees and rank-and-file scientists have clashed with Bush appointees over a number of those of issues, including whether the federal government should allow California to regulate tailpipe emissions from automobiles…”

Obama has vowed to bring integrity back to the agency by reversing Bush’s executive orders:

“I think the slow chipping away against clean air and clean water has been deeply disturbing. Much of it hasn’t gone through Congress. It was done by fiat. That is something that can be changed by an administration, in part by reinvigorating the EPA, which has been demoralized.”

The importance of who is selected to lead the EPA is so profound, Obama is considering elevating the position to cabinet-level status. In fact, Gene Karpinski, president of the League of Conservation Voters, believes,

“The most important challenge facing the new administration is making serious progress on global warming pollution. That includes specific steps such as regulating carbon dioxide as a pollutant.”
Who will Obama chose for this formidable task? The following is a shortlist of possible EPA candidates being discussed in the mainstream media:

Kathleen McGinty-Former Pennsylvania Department of Environmental Protection Head: McGinty served as a top environmental official under President Clinton, and she has promoted renewable energy legislation in Pennsylvania while working with utility companies.
Mary Nichols-California Air Resources Board Leader: Another former Clinton official, Nichols is working on the development of rules to limit heat-trapping emissions from power plants in California. Nichols is Senator Boxer’s top pick for the job.
Ian Bowles-Massachusetts Department of Environmental Protection Leader: Bowles worked with officials from other Northeast U.S. states to open the first American market for trading greenhouse gas permits.
Kathleen Sibelius-Kansas Governor: Sebelius vetoed the Kansas legislature’s attempt to overrule the denial of a permit to expand a coal-fired power plant.
Lisa Jackson-New Jersey Environmental Commissioner: Jackson is the current co-chair of Barack Obama’s environmental transition team. She has worked at the EPA for 15 years and has focused on hazardous waste clean up and enforcement in New Jersey.
Robert F. Kennedy, Jr.-Environmental Lawyer: Robert F. Kennedy, Jr. is probably the most well-known candidate on the shortlist:

Robert F. Kennedy, Jr.’s reputation as a resolute defender of the environment stems from a litany of successful legal actions. Mr. Kennedy was named one of Time magazine’s “Heroes for the Planet” for his success helping Riverkeeper lead the fight to restore the Hudson River.

According to Stop Global Warming, Lisa Jackson is the leading candidate to head Obama’s EPA, but no matter who gets the job, the task of curbing the effects of climate change immediately is monumental. Frank O’Donnell, president of Clean Air Watch, explained, “During the last eight years, we have made precious little progress against air pollution and we’ve missed some opportunities.” We can’t afford to miss any more opportunities.

Friday, December 5, 2008

Why electric cars have stalled

Facing technical challenges and a weak market, many of Silicon Valley's electric-car startups are changing direction.

1 of 4Wrightspeed's 180-degree turn

Full story: Why electric cars have stalled

The Wrightspeed X1, a sports car whose three-second acceleration from 0 to 60 makes it one of the fastest autos in the world, is also super-clean: It's powered by an electric motor and gets about 170 mpg. Ian Wright, the Burlingame, Calif., entrepreneur who created the X1 several years ago, had planned on ramping up production on a line of similar electric cars in 2009. But over the summer, he changed his mind.
"It's one thing to build electric cars, but it's another to go out and get some kind of respectable market size and funding," Wright says. "At this stage of the game, when oil is cheap and batteries still expensive, spending two to three -times the price on an electric car doesn't really make sense."

In a 180-degree turn from where his company, Wrightspeed, was a year ago, Wright has completely abandoned the concept of bringing an electric car to market. Instead, while he waits for the electric vehicle market to mature, Wright is focusing on a more lucrative venture: Wrightspeed will make and sell electric powertrains - the battery pack, software, and other components that generate power to a vehicle - to existing car and truck manufacturer.

"We're not looking at GM or Tesla Motors," Wright says. "Electric vehicles for the mass-market - that's at least 20 years away."

By Maggie Overfelt

Thursday, December 4, 2008

Obama Likely to Boost Water Quality Rules After Years of Lax Regulation

By Kent Garber

The Obama administration and the next Congress are being urged, by a growing number of academics, environmentalists, and lawmakers, to address the country's water problems, including its dwindling supplies, inadequate environmental protections, and stalled cleanup efforts.

the past decade, a potent combination of Supreme Court decisions, Bush administration regulatory actions, and congressional inaction—coupled with recent droughts and the specter of more pronounced problems from climate change—has helped breed crises of both water quality and water availability, they say.

At the top of their priority list: reviving federal laws—particularly the Clean Water Act—that have been weakened or narrowly interpreted in recent years; boosting funding for the nation's faltering and aging water infrastructure; and strengthening the Environmental Protection Agency's regulation of water pollution from industry and power plants.

Many of these priorities appear to align with those of Barack Obama. In his remarks about a stimulus package last week, Obama stressed the need for infrastructure improvement. During the campaign, he touted his support for water protection in battleground states like Florida, pledging to help protect and restore the Florida Everglades. His campaign advisers, meantime, say he will support legislation to restore the full scope of environmental laws that were weakened under the current administration.

Environmentalists want him to start by rejuvenating the Clean Water Act—the main water-pollution control act in the United States. Passed in 1972, the law was interpreted by both Congress and the courts for nearly 30 years as protecting virtually all federal waters. But in 2001, and again in 2006, the Supreme Court handed down rulings that served, in effect, to limit the law's reach.

Now, more than 20 million acres of wetlands, along with more than half of the country's steams and rivers, are more vulnerable to pollution as a result of the court's decisions and EPA rules that have followed. "Clean water enforcement is essentially broken at this point," says Joan Mulhern, senior legislative counsel at Earthjustice, a nonprofit law firm that has prosecuted many of the most high-profile environmental cases of the past decade. Moreover, because of uncertainty resulting from the court's 2006 decision, the EPA has delayed processing hundreds of environmental violations.

To return the Clean Water Act to its original standing, environmentalists are asking Congress to pass legislation clarifying that the law applies not just to main waterways or waterways closely linked to main waterways, as some justices on the Supreme Court have argued, but to all types of federal waters. Such a bill already has been proposed by Senate Environment and Public Works Committee Chair Barbara Boxer and has been endorsed in principle by Obama. "I would not be surprised if that actually got passed within the first few years of the Obama administration," says Florida State law Prof. Robin Craig, one of the nation's top experts on water law.

Another concern is the condition of the nation's sewage systems and water treatment facilities. There is bipartisan consensus that the nation's water infrastructure is in urgent need of repair. "The nation's sewage infrastructure for the 21st century is in abominable shape," says Mulhern.

In June, presaging an argument he made last week supporting a second stimulus package, Obama told a crowd in Flint, Mich., "If we want to keep up with China or Europe, we can't settle for crumbling roads and bridges, aging water and sewer pipes. It's gotten so bad that the American Society of Civil Engineers gave our national infrastructure a D. " Environmentalists are hopeful that any stimulus package Obama assembles will include at least $10 billion for water treatment systems and water-related projects. They note that the Clean Water Act at one point provided $1.35 billion a year for infrastructure improvements. Because of recent budget strains, that amount has been cut by more than half.

And as Craig and others point out, water quality is only half the battle. Water supply is the other half. "We are running out of water, and I do not say that facetiously," she says. Large parts of the United States depend on aquifers—such as the Ogallala aquifer under Texas and Oklahoma—that contain what Craig calls "fossil water" and are unlikely to refill.

Climate change is exacerbating water problems in many regions and water shortages are, in turn, making water quality issues more extreme. "These are not unrelated issues," says Craig. "If you don't have enough water in a river, you make whatever pollutants are there worse because they're more concentrated."

Wednesday, December 3, 2008

Studies find laser printers emit lung-damaging particles on the order of cigarette smoking

By Rick C. Hodgin
Berlin (Germany) - Fraunhofer-Gesellschaft, a German research company that just completed a study on laser printer emissions, reports that volatile organic-chemical emissions (ozone), silicon oil, paraffin and ultra-fine particles are emitted during laser printing. Though they don't go into significant detail on the health-related issues. However, several previous Australian research studies show that the particle emissions are comparable to cigarette smoking. The Australian study also suggests that printer companies should be regulated by the government as their products are often a major source of inter-office air pollution.

There is a particular smell emitted when laser printers are in use. It's ozone, the "volatile organic-chemical" identified in these studies. In relatively high concentrations above 1 ppm, it can cause irritation to eyes, nose, throat and lungs. Most people can smell it in much lower concentrations though, even down to 0.01 ppm. It is interesting to note that ozone is responsible for the cracking found in old car tires. Modern tires have additives which prevent damage from ozone.

Because of the ozone smell, many consumers were concerned the redolent emissions were either toxic, carcinogenic or both. The studies so far indicate that, while they aren't 100% sure, all of the mechanisms are in place to effectively deliver toxic or carcinogenic particles.

Innocuous paraffins and silicon oils

The studies found that even printers which do not use toner, but rather some form of high heat printing mechanisms (like FAX machines), also emit certain types of chemicals. These gather and collate in the air and form ultra-fine particles of both silicon oil and paraffins.

Silicon oil is innocuous. It is comprised of alternating atoms of silicon and oxygen and is one of the two main ingredients in Silly Putty (with boric acid being the other) which children often eat. It has countless electrical and medical uses as a non-conducting, nontoxic lubricant. Sometimes it is added to cooking oils to reduce foaming at high temperatures. It's also non-flammable.

Paraffin is equally innocuous: It is the name for any of a series of hydrocarbons in the form CnH(2n+2), such as C20H42, which is paraffin wax. Or, the simplest form of paraffin, which is methane (CH4). Other forms include octane, kerosene and mineral oil. The name paraffin comes from the Latin parum and affinis, which means "lacking affinity" or, more specifically, "lacking reactivity." Various paraffin forms are found in all kinds of edible applications, including candies, chewing gums, waxy cheese packages, canning topping, and are used because of their low health danger.

Possibly dangerous toner particles

The Fraunhofer study, which was paid for by "the printer and copier manufacturers in a German Association for Information Technology, Telecommunications and New Media, called BITKOM," found that the laser printers emit almost no particles of toner. However, several previous studies found many toner particle emissions.

The previously identified trends indicate also that when toner cartridges are new, they emit more particles than when they are old. Also, when printing heavy graphics or when large amounts of toner are used on the print surface, particle emissions grow.

These toner particles are of particular interest in the medical field, because they are comprised of both extremely tiny and very large particles.

According to a mid-August, 2007 article in the American Chemical Society's semi-monthly Environment Science and Technology journal, the smallest particles can find their way into the deepest lung crevices. The larger particles, on the other hand, are capable of gathering and carrying a multitude of toxins into the body.

Regulations proposed

The 2007 Australian findings were incidental. The researchers were originally looking at alternate sources of pollution. However, during the course of their study, they realized that office laser printers were increasing indoor air pollution by about 500%. These studies found the dangers high enough to prompt a call for governmental regulation.

According to Lidia Morawska, a PhD working with the American Chemical Society, "It wasn't an area that we consciously decided to study. We came across it by chance. Initially we were studying the efficiency of ventilation systems to protect office settings from outdoor air pollutants. We soon realized that we were seeing air pollution originating indoors, from laser printers."

The study indicated the 500% increase from laser printer operations alone. She goes on to say, "By all means, this is an important indoor source of pollution. There should be regulations."

These earlier, reports of the dangers of air pollution from laser printers came out in 2007. The Fraunhofer report was released today. And whereas Fraunhofer indicates the same kind of particles found in the atmosphere as the previous reports, they do not go into details relating to health side-effects.

Since "technical and financial support was provided by the printer and copier manufacturers in the German Association (BITCOM)," we cannot help but wonder why they did not disclose the full health ramifications or to fully describe the particle emissions.

Monday, December 1, 2008

10 Big Energy Myths

In reality, today's bulky and expensive solar panels capture only 10% or so of the sun's energy, but rapid innovation in the US means that the next generation of panels will be much thinner, capture far more of the energy in the sun's light and cost a fraction of what they do today. They may not even be made of silicon. First Solar, the largest manufacturer of thin panels, claims that its products will generate electricity in sunny countries as cheaply as large power stations by 2012.

Other companies are investigating even more efficient ways of capturing the sun's energy, for example the use of long parabolic mirrors to focus light on to a thin tube carrying a liquid, which gets hot enough to drive a steam turbine and generate electricity. Spanish and German companies are installing large-scale solar power plants of this type in North Africa, Spain and the south-west of America; on hot summer afternoons in California, solar power stations are probably already financially competitive with coal. Europe, meanwhile, could get most of its electricity from plants in the Sahara desert. We would need new long-distance power transmission but the technology for providing this is advancing fast, and the countries of North Africa would get a valuable new source of income.

Myth 2: wind power is too unreliable

Actually, during some periods earlier this year the wind provided almost 40% of Spanish power. Parts of northern Germany generate more electricity from wind than they actually need. Northern Scotland, blessed with some of the best wind speeds in Europe, could easily generate 10% or even 15% of the UK's electricity needs at a cost that would comfortably match today's fossil fuel prices.

The intermittency of wind power does mean that we would need to run our electricity grids in a very different way. To provide the most reliable electricity, Europe needs to build better connections between regions and countries; those generating a surplus of wind energy should be able to export it easily to places where the air is still. The UK must invest in transmission cables, probably offshore, that bring Scottish wind-generated electricity to the power-hungry south-east and then continue on to Holland and France. The electricity distribution system must be Europe-wide if we are to get the maximum security of supply.

We will also need to invest in energy storage. At the moment we do this by
pumping water uphill at times of surplus and letting it flow back down the mountain when power is scarce. Other countries are talking of developing "smart grids" that provide users with incentives to consume less electricity when wind speeds are low. Wind power is financially viable today in many countries, and it will become cheaper as turbines continue to grow in size, and manufacturers drive down costs. Some projections see more than 30% of the world's electricity eventually coming from the wind. Turbine manufacture and installation are also set to become major sources of employment, with one trade body predicting that the sector will generate 2m jobs worldwide by 2020.

Myth 3: marine energy is a dead-end

The thin channel of water between the north-east tip of Scotland and Orkney contains some of the most concentrated tidal power in the world. The energy from the peak flows may well be greater than the electricity needs of London. Similarly, the waves off the Atlantic coasts of Spain and Portugal are strong, consistent and able to provide a substantial fraction of the region's power. Designing and building machines that can survive the harsh conditions of fast-flowing ocean waters has been challenging and the past decades have seen repeated disappointments here and abroad. This year we have seen the installation of the first tidal turbine to be successfully connected to the UK electricity grid in Strangford Lough, Northern Ireland, and the first group of large-scale wave power generators 5km off the coast of Portugal, constructed by a Scottish company.

But even though the UK shares with Canada, South Africa and parts of South America some of the best marine energy resources in the world, financial support has been trifling. The London opera houses have had more taxpayer money than the British marine power industry over the past few years. Danish support for wind power helped that country establish worldwide leadership in the building of turbines; the UK could do the same with wave and tidal power.

Myth 4: nuclear power is cheaper than other low-carbon sources of electricity

If we believe that the world energy and environmental crises are as severe as is said, nuclear power stations must be considered as a possible option. But although the disposal of waste and the proliferation of nuclear weapons are profoundly important issues, the most severe problem may be the high and unpredictable cost of nuclear plants.

The new nuclear power station on the island of Olkiluoto in western Finland is a clear example. Electricity production was originally supposed to start this year, but the latest news is that the power station will not start generating until 2012. The impact on the cost of the project has been dramatic. When the contracts were signed, the plant was supposed to cost €3bn (£2.5bn). The final cost is likely to be more than twice this figure and the construction process is fast turning into a nightmare. A second new plant in Normandy appears to be experiencing similar problems. In the US, power companies are backing away from nuclear because of fears over uncontrollable costs.

Unless we can find a new way to build nuclear power stations, it looks as though CO2 capture at coal-fired plants will be a cheaper way of producing low-carbon electricity. A sustained research effort around the world might also mean that cost-effective carbon capture is available before the next generation of nuclear plants is ready, and that it will be possible to fit carbon-capture equipment on existing coal-fired power stations. Finding a way to roll out CO2 capture is the single most important research challenge the world faces today. The current leader, the Swedish power company Vattenfall, is using an innovative technology that burns the coal in pure oxygen rather than air, producing pure carbon dioxide from its chimneys, rather than expensively separating the CO2 from other exhaust gases. It hopes to be operating huge coal-fired power stations with minimal CO2 emissions by 2020.

Myth 5: electric cars are slow and ugly

We tend to think that electric cars are all like the G Wiz vehicle, with a limited range, poor acceleration and an unprepossessing appearance. Actually, we are already very close to developing electric cars that match the performance of petrol vehicles. The Tesla electric sports car, sold in America but designed by Lotus in Norfolk, amazes all those who experience its awesome acceleration. With a price tag of more than $100,000, late 2008 probably wasn't a good time to launch a luxury electric car, but the Tesla has demonstrated to everybody that electric cars can be exciting and desirable. The crucial advance in electric car technology has been in batteries: the latest lithium batteries - similar to the ones in your laptop - can provide large amounts of power for acceleration and a long enough range for almost all journeys.

Batteries still need to become cheaper and quicker to charge, but the UK's largest manufacturer of electric vehicles says that advances are happening faster than ever before. Its urban delivery van has a range of over 100 miles, accelerates to 70mph and has running costs of just over 1p per mile. The cost of the diesel equivalent is probably 20 times as much. Denmark and Israel have committed to develop the full infrastructure for a switch to an all-electric car fleet. Danish cars will be powered by the spare electricity from the copious resources of wind power; the Israelis will provide solar power harvested from the desert.

Myth 6: biofuels are always destructive to the environment

Making some of our motor fuel from food has been an almost unmitigated disaster. It has caused hunger and increased the rate of forest loss, as farmers have sought extra land on which to grow their crops. However the failure of the first generation of biofuels should not mean that we should reject the use of biological materials forever. Within a few years we will be able to turn agricultural wastes into liquid fuels by splitting cellulose, the most abundant molecule in plants and trees, into simple hydrocarbons. Chemists have struggled to find a way of breaking down this tough compound cheaply, but huge amounts of new capital have flowed into US companies that are working on making a petrol substitute from low-value agricultural wastes. In the lead is Range Fuels, a business funded by the venture capitalist Vinod Khosla, which is now building its first commercial cellulose cracking plant in Georgia using waste wood from managed forests as its feedstock.

We shouldn't be under any illusion that making petrol from cellulose is a solution to all the problems of the first generation of biofuels. Although cellulose is abundant, our voracious needs for liquid fuel mean we will have to devote a significant fraction of the world's land to growing the grasses and wood we need for cellulose refineries. Managing cellulose production so that it doesn't reduce the amount of food produced is one of the most important issues we face.

Myth 7: climate change means we need more organic agriculture

The uncomfortable reality is that we already struggle to feed six billion people. Population numbers will rise to more than nine billion by 2050. Although food production is increasing slowly, the growth rate in agricultural productivity is likely to decline below population increases within a few years. The richer half of the world's population will also be eating more meat. Since animals need large amounts of land for every unit of meat they produce, this further threatens food production for the poor. So we need to ensure that as much food as possible is produced on the limited resources of good farmland. Most studies show that yields under organic cultivation are little more than half what can be achieved elsewhere. Unless this figure can be hugely improved, the implication is clear: the world cannot feed its people and produce huge amounts of cellulose for fuels if large acreages are converted to organic cultivation.

Myth 8: zero carbon homes are the best way of dealing with greenhouse gas emissions from buildings

Buildings are responsible for about half the world's emissions; domestic housing is the most important single source of greenhouse gases. The UK's insistence that all new homes are "zero carbon" by 2016 sounds like a good idea, but there are two problems. In most countries, only about 1% of the housing stock is newly built each year. Tighter building regulations have no effect on the remaining 99%. Second, making a building genuinely zero carbon is extremely expensive. The few prototype UK homes that have recently reached this standard have cost twice as much as conventional houses.

Just focusing on new homes and demanding that housebuilders meet extremely high targets is not the right way to cut emissions. Instead, we should take a lesson from Germany. A mixture of subsidies, cheap loans and exhortation is succeeding in getting hundreds of thousands of older properties eco-renovated each year to very impressive standards and at reasonable cost. German renovators are learning lessons from the PassivHaus movement, which has focused not on reducing carbon emissions to zero, but on using painstaking methods to cut emissions to 10 or 20% of conventional levels, at a manageable cost, in both renovations and new homes. The PassivHaus pioneers have focused on improving insulation, providing far better air-tightness and warming incoming air in winter, with the hotter stale air extracted from the house. Careful attention to detail in both design and building work has produced unexpectedly large cuts in total energy use. The small extra price paid by householders is easily outweighed by the savings in electricity and gas. Rather than demanding totally carbon-neutral housing, the UK should push a massive programme of eco-renovation and cost-effective techniques for new construction.

Myth 9: the most efficient power stations are big

Large, modern gas-fired power stations can turn about 60% of the energy in fuel into electricity. The rest is lost as waste heat.

Even though 5-10% of the electricity will be lost in transmission to the user, efficiency has still been far better than small-scale local generation of power. This is changing fast.

New types of tiny combined heat and power plants are able to turn about half the energy in fuel into electricity, almost matching the efficiency of huge generators. These are now small enough to be easily installed in ordinary homes. Not only will they generate electricity but the surplus heat can be used to heat the house, meaning that all the energy in gas is productively used. Some types of air conditioning can even use the heat to power their chillers in summer.

We think that microgeneration means wind turbines or solar panels on the roof, but efficient combined heat and power plants are a far better prospect for the UK and elsewhere. Within a few years, we will see these small power plants, perhaps using cellulose-based renewable fuels and not just gas, in many buildings. Korea is leading the way by heavily subsidising the early installation of fuel cells at office buildings and other large electricity users.

Myth 10: all proposed solutions to climate change need to be hi-tech

The advanced economies are obsessed with finding hi-tech solutions to reducing greenhouse gas emissions. Many of these are expensive and may create as many problems as they solve. Nuclear power is a good example. But it may be cheaper and more effective to look for simple solutions that reduce emissions, or even extract existing carbon dioxide from the air. There are many viable proposals to do this cheaply around the world, which also often help feed the world's poorest people. One outstanding example is to use a substance known as biochar to sequester carbon and increase food yields at the same time.

Biochar is an astonishing idea. Burning agricultural wastes in the absence of air leaves a charcoal composed of almost pure carbon, which can then be crushed and dug into the soil. Biochar is extremely stable and the carbon will stay in the soil unchanged for hundreds of years. The original agricultural wastes had captured CO2 from the air through the photosynthesis process; biochar is a low-tech way of sequestering carbon, effectively for ever. As importantly, biochar improves fertility in a wide variety of tropical soils. Beneficial micro-organisms seem to crowd into the pores of the small pieces of crushed charcoal. A network of practical engineers around the tropical world is developing the simple stoves needed to make the charcoal. A few million dollars of support would allow their research to benefit hundreds of millions of small farmers at the same time as extracting large quantities of CO2 from the atmosphere.

Sunday, November 30, 2008

Ocean currents can power the world

A revolutionary device that can harness energy from slow-moving rivers and ocean currents could provide enough power for the entire world, scientists claim.

By Jasper Copping

Existing technologies require an average current of five or six knots to operate efficiently, while most of the earth's currents are slower than three knots The technology can generate electricity in water flowing at a rate of less than one knot - about one mile an hour - meaning it could operate on most waterways and sea beds around the globe.

Existing technologies which use water power, relying on the action of waves, tides or faster currents created by dams, are far more limited in where they can be used, and also cause greater obstructions when they are built in rivers or the sea. Turbines and water mills need an average current of five or six knots to operate efficiently, while most of the earth's currents are slower than three knots.

The new device, which has been inspired by the way fish swim, consists of a system of cylinders positioned horizontal to the water flow and attached to springs.

As water flows past, the cylinder creates vortices, which push and pull the cylinder up and down. The mechanical energy in the vibrations is then converted into electricity.

Cylinders arranged over a cubic metre of the sea or river bed in a flow of three knots can produce 51 watts. This is more efficient than similar-sized turbines or wave generators, and the amount of power produced can increase sharply if the flow is faster or if more cylinders are added.

A "field" of cylinders built on the sea bed over a 1km by 1.5km area, and the height of a two-storey house, with a flow of just three knots, could generate enough power for around 100,000 homes. Just a few of the cylinders, stacked in a short ladder, could power an anchored ship or a lighthouse.

Systems could be sited on river beds or suspended in the ocean. The scientists behind the technology, which has been developed in research funded by the US government, say that generating power in this way would potentially cost only around 3.5p per kilowatt hour, compared to about 4.5p for wind energy and between 10p and 31p for solar power. They say the technology would require up to 50 times less ocean acreage than wave power generation.

The system, conceived by scientists at the University of Michigan, is called Vivace, or "vortex-induced vibrations for aquatic clean energy".

Michael Bernitsas, a professor of naval architecture at the university, said it was based on the changes in water speed that are caused when a current flows past an obstruction. Eddies or vortices, formed in the water flow, can move objects up and down or left and right.

"This is a totally new method of extracting energy from water flow," said Mr Bernitsas. "Fish curve their bodies to glide between the vortices shed by the bodies of the fish in front of them. Their muscle power alone could not propel them through the water at the speed they go, so they ride in each other's wake."

Such vibrations, which were first observed 500 years ago by Leonardo DaVinci in the form of "Aeolian Tones", can cause damage to structures built in water, like docks and oil rigs. But Mr Bernitsas added: "We enhance the vibrations and harness this powerful and destructive force in nature.

"If we could harness 0.1 per cent of the energy in the ocean, we could support the energy needs of 15 billion people. In the English Channel, for example, there is a very strong current, so you produce a lot of power."

Because the parts only oscillate slowly, the technology is likely to be less harmful to aquatic wildlife than dams or water turbines. And as the installations can be positioned far below the surface of the sea, there would be less interference with shipping, recreational boat users, fishing and tourism.

The engineers are now deploying a prototype device in the Detroit River, which has a flow of less than two knots. Their work, funded by the US Department of Energy and the US Office of Naval Research, is published in the current issue of the quarterly Journal of Offshore Mechanics and Arctic Engineering.

HVAC boot cleared of Asbestos in Los Angeles