Tag Archives: clean energy

Battery Fires Reveal Risks of Storing Large Amounts of Energy

Battery Fires Reveal Risks of Storing Large Amounts of Energy: Scientific American.

STORAGE RISK: Storing large amounts of energy, in batteries or other devices, inherently poses risks — but also offers benefits. Image: Mariordo/Wikimedia Commons

People still need electricity when the wind isn’t blowing and the sun isn’t shining, which is why renewable energy developers are increasingly investing in energy storage systems. They need to sop up excess juice and release it when needed.

However, storing large amounts of energy, whether it’s in big batteries for electric cars or water reservoirs for the electrical grid, is still a young field. It presents challenges, especially with safety.

The most recent challenge first appeared in May, three weeks after a safety crash test on the Chevrolet Volt, General Motors Co.’s plug-in hybrid. The wrecked vehicle caught fire on its own in a storage facility, raising questions about its lithium-ion battery.

Last week, after a series of additional side-impact crash tests on the Volt battery, the National Highway Traffic Safety Administration (NHTSA) launched what it called a “safety defect investigation” into the risk of fire in a Chevy Volt that has been involved in a serious accident.

Problems have also afflicted spinning flywheels, which allow power plants and other large energy users to store and release powerful surges of energy. In Stephentown, N.Y., Beacon Power’s 20-megawatt flywheel energy storage facility suffered two flywheel explosions, one on July 27 — just two weeks after it opened — and one on Oct. 13. The company declared bankruptcy earlier this month.

In Japan, sodium-sulfur batteries at Mitsubishi Materials Corp.’s Tsukuba plant in Ibaraki prefecture caught on fire on Sept. 21. It took firefighters more than eight hours to control the blaze, and authorities declared it extinguished on Oct. 5.

NGK Insulators Ltd., the company that manufactured the energy storage system, said it is still investigating the incident’s cause and has halted production of its sodium-sulfur cells, which are installed in 174 locations across six countries.

“Clearly, storing large amounts of energy is difficult from a physics standpoint; [the energy] would rather be somewhere else,” said Paul Denholm, a senior energy analyst at the National Renewable Energy Laboratory.

He explained that energy naturally wants to spread out, so packing it into a small space like a battery or a fuel cell creates the risk of an uncontrolled energy release like a fire or explosion. Similar issues come up with mechanical storage, whether it’s water behind a dam, compressed air underground or spinning flywheels.

Some storage risks are ‘grandfathered’
However, these risks are not unique to storing electricity. Fossil fuels, which are technically forms of stored energy, pose plenty of problems in their extraction, refining, distribution and delivery.

“We basically have grandfathered these risk factors. Gasoline catches on fire all the time,” said Denholm. Electrical energy storage systems aren’t inherently riskier than petroleum or natural gas, according to Denholm, but their risks are different.

The NHTSA shares Denholm’s assessment when it comes to cars. “Let us be clear: NHTSA does not believe electric vehicles are at a greater risk of fire than other vehicles,” said the agency in a press release earlier this month responding to the Volt fire. “It is common sense that the different designs of electric vehicles will require different safety standards and precautions.”

For batteries, the main issue is how they control the heat they generate. “What you really want to avoid is cascading failure,” said Denholm. “A failure of any one of those batteries is not a huge event, but if you don’t have proper thermal management, a failure in one battery can cause failure in another.”

This condition, known as a thermal runaway, happens when a cell fails and releases its energy as heat. This heat can cause adjacent cells to fail and generate heat, as well, leading to melting materials and fires.

Controlling temperatures is relatively simple when the batteries are in a fixed location, say, next to a wind farm, but it becomes harder when they are placed in a car or bus.

“The biggest thing that people become concerned about [for batteries in cars] is the ability to be able to tolerate abuse,” said Joe Redfield, principal engineer at the Southwest Research Institute, a nonprofit engineering research and development group.

In a car, a battery is exposed to a wide range of humidities, temperatures and electrical loads. All of these factors influence the battery’s reliability, and if they get too extreme, they can cause a thermal runaway condition.

New problem for firefighters
The problem is compounded by the fact that newer lithium-ion batteries store more electricity than other electrochemical storage systems. “The lead-acid battery has been around a long time” and is a mature technology, said Redfield. “The energy levels of lithium-ion batteries are much, much, much greater than that of lead-acid storage.”

This becomes a major problem for firefighters and first responders in the event of an accident involving lithium-ion batteries. Water can’t always be used to extinguish an electrical fire, since water can conduct electricity.

In addition, in the case of a thermal runaway, it’s usually not the batteries that catch fire but their fumes, though lithium itself is flammable. Even after the fire is extinguished, the batteries can still generate tremendous amounts of heat and reignite fumes, hampering rescue efforts.

One solution is to separate batteries into modules, making it easier to isolate a failed battery from the rest. Another trick is to have a master kill switch, a mechanism that quickly disables the electrical system and discharges the batteries.

The Department of Energy and the National Fire Protection Association are working together to train firefighters and rescue workers to identify these switches in vehicles and grid storage systems as well as in how to respond to battery fires, according to the NHTSA.

Redfield said that the best way to prevent such incidents is with a battery management system that evenly distributes electrical loads and controls temperatures. “It’s not just for safety; it’s primarily there to provide performance and battery life,” he said.

Electrics get high marks in crash tests

“As the operating temperature increases, the lifetime diminishes dramatically. You want to ensure the longest battery life, and if you achieve that, then you’re clearly in the safety limits of the operating environment,” he added.

Overall, Redfield expects that energy storage systems will help increase renewable energy use and curb fossil fuel dependence in the United States. The bumps along the road are significant, but they do not result from an inherent flaw in the idea.

“Failures in new technology have almost always been the result of design shortcuts that were made in putting the new technology into progress. Every now and then, you have some uncharted territory — things we haven’t seen before — but typically, they are few and far between,” said Redfield.

“It really is going down the same path we’ve gone down many times before. We don’t need to make the same mistakes we’ve made with liquid fuels.” After the earlier testing, NHTSA gave the Volt a five-star crash test rating — the agency’s highest — and it did the same for Nissan’s all-electric Leaf.

Meanwhile, a second testing agency, the Insurance Institute for Highway Safety, has given the Chevrolet Volt a “G,” the highest safety score possible, after side crash tests on the front, side, rear and rollovers.

Research by an affiliate of the insurance group, the Highway Loss Data Institute, estimates that overall chances of being injured in a crash are 25 percent lower in hybrids because their large batteries make them heavier than similar gasoline-powered cars.

Reprinted from Climatewire with permission from Environment & Energy Publishing, LLC. www.eenews.net, 202-628-6500

Climate Change Evaporates Part of China's Hydropower

Climate Change Evaporates Part of China’s Hydropower: Scientific American.

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WATER FALL: Unusually low water levels in many Chinese rivers has contributed to a big drop in hydropower production. Image: Tomasz Dunn/Flickr

SHANGHAI — China has set ambitious goals for itself to develop hydropower to help mitigate the risks of climate change, but increasing extreme weather events likely rooted in climate change are now sabotaging the goals’ foundations.

The latest blow came in September, when many major rivers across China ran into an unusual shrinkage, with less than 20 percent water remaining at some stretches. As a result, the nation’s hydroelectric generation dropped by almost a quarter compared with last year. There has been an ever-widening decrease in power each month since July, according to a recent government statement.

As water stocks in key hydro stations decline, the regular dry season is approaching. The resulting stress on hydroelectric generation will last into next year, the statement said.

The Chinese government has yet to explain why the water flows slumped. But experts blamed it on climate change, warning of more future droughts in areas traditionally blessed with water.

If this expectation comes true, it will hamper China’s hydropower sector, which contributes most of the country’s carbon-free electricity. It will also threaten a national strategy in transmitting electricity from resource-rich western China to feed the country’s power-hungry manufacturing sector, most of which is in the east.

For Guangdong province, located on China’s east coast, this threat has already turned into a daily reality. Since its western neighbors this year failed to send as much electricity as usual, the manufacturing hub, with a capacity to produce more than half of the world’s desktops and toys, is forced to conserve electricity.

Turbines left high and dry
China Southern Power Grid, the region’s electricity distributor, attributed the energy shortage partly to the evaporation of hydropower.

As of July, on average, not even half of its installed hydropower capacity found water to turn turbines, the company’s statistics show. And several major hydro stations, built as part of the west-to-east electricity transmission plan, failed to do their jobs.

Goupitan, the largest hydroelectric generator in Guizhou province, reportedly produced only 10 percent of its normal output per day, due to shrinking water flows. And in another hydro station called Longtan, located in the Guangxi region, this year’s missing rain dropped its reservoir’s water level to a point dozens of meters lower than previous years.

“This will definitely negatively affect our hydroelectric production from now to next summer,” said Li Yanguang, who is in charge of public relations in the power station. Asked whether next summer — a regular rainy season — could make the situation better, Li answered in a cautious tone.

“This totally depends on weather,” he said. “We can’t predict that.”

Hydro growth plan sticks despite falling power output
But Lin Boqiang, one of China’s leading energy experts, is confident that the nation’s hydroelectric generation may just go in one direction: getting worse.

“If climate change caused this year’s water flow decreases, which I think it did, and then its impact [on rivers] will be a long term. It will take a toll on China’s hydroelectric output, and also push up the cost of using it,” explained Lin, who directs the China Center for Energy Economics Research at Xiamen University.

But still, from Lin’s point of view, such setbacks can’t compete with the Chinese desire for tapping more water power. China, already the world’s largest hydropower user, plans to add another 120 gigawatts by 2015 — a crucial step toward greening 15 percent of its power mix by the end of the decade.

Yang Fuqiang, a senior climate and energy expert at the Natural Resources Defense Council, agreed that China’s hydropower plan will stand, though not primarily for energy supply concerns.

Although a climate-resilient approach is factored into the designs of hydro projects, China is still likely to suffer from hydroelectric output decline, says Yang. But the nation can seek more clean energy from the sun or wind, which won’t be affected by climate change, and get the electricity generated elsewhere via a smart grid, he said, referring to an advanced transmission infrastructure China has been building.

So what’s the point of keeping hydro?

“In the future, the importance of hydro projects won’t be on power generation, but on water management,” Yang explained. “It helps control floods, ensure ships transportation and reserve water — a function that [water-scarce] China needs badly.”

Reprinted from Climatewire with permission from Environment & Energy Publishing, LLC. www.eenews.net, 202-628-6500

Shale Gas Needs More Openness & Better Data – ScienceInsider

Federal Committee: Shale Gas Needs More Openness, Better Data – ScienceInsider.

A U.S. Department of Energy committee has waded into the fracas over the production of natural gas from shale using the controversial hydrofracturing, or fracking, technology, with a call for shared data. Much about how industry produces shale gas must be improved, a report released today finds, in order to reduce shale gas’s environmental impact. “We share the belief that development can be done in a way that results in minimal impacts,” says geophysicist Mark Zoback of Stanford University, one of seven members of the subcommittee advising Secretary of Energy Steven Chu. But “to do that, there have to be improvements in the way shale gas companies do their business.”

The subcommittee to the secretary’s Energy Advisory Board was not asked who should be regulating shale gas, Zoback says. Regulation now lies primarily with the states. But “we’re pointing out what can and should be done.” To regain public trust, the report says, much information about shale gas should become readily available to the public, starting with the chemical recipes for the fluids pumped at high pressure into shale to free up the gas. Those fluids sometimes spill onto the surface and into waterways. And much more information should be gathered on the environment before, during, and after drilling. The debate over whether and how drilling and fracking contaminate groundwater with gas—the infamous flaming water faucet of the documentary Gasland—would benefit especially. “We feel very strongly that having good data will advance a lot of the issues,” Zoback says.

Some sort of national organization focused on shale gas should also be formed, the report says. It could create a national database of all public information as well as disseminate best practices to industry as they evolve. Added support for existing mechanisms that aid communication among state and federal regulators would also help.

“It’s a remarkable report,” says Philip Sharp, president of the think tank Resources for the Future in Washington, D.C. “It’s a balanced, high-caliber group with public input. The report is remarkable in having honest, actionable proposals in it. What they say will get attention.”

Wind and wave farms could affect Earth's energy balance

Wind and wave farms could affect Earth’s energy balance – environment – 30 March 2011 – New Scientist.

UPDATE, April 6: This article has elicited a considerable amount of interest, and some criticism. We always welcome discussions of the stories we publish. Some readers felt the original headline (Wind and wave energies are not renewable after all) was misleading, so to address these concerns we have changed it. We have also been made aware of a wider debate about Kleidon’s research that we did not address in the original article: we will continue to follow this issue and report back on what we find.

Editorial: The sun is our only truly renewable energy source

The idea that we can draw endless supplies of clean energy from the wind and waves just doesn’t add up

WITNESS a howling gale or an ocean storm, and it’s hard to believe that humans could make a dent in the awesome natural forces that created them. Yet that is the provocative suggestion of one physicist who has done the sums.

He concludes that it is a mistake to assume that energy sources like wind and waves are truly renewable. Build enough wind farms to replace fossil fuels, he says, and we could seriously deplete the energy available in the atmosphere, with consequences as dire as severe climate change.

Axel Kleidon of the Max Planck Institute for Biogeochemistry in Jena, Germany, says that efforts to satisfy a large proportion of our energy needs from the wind and waves will sap a significant proportion of the usable energy available from the sun. In effect, he says, we will be depleting green energy sources. His logic rests on the laws of thermodynamics, which point inescapably to the fact that only a fraction of the solar energy reaching Earth can be exploited to generate energy we can use.

When energy from the sun reaches our atmosphere, some of it drives the winds and ocean currents, and evaporates water from the ground, raising it high into the air. Much of the rest is dissipated as heat, which we cannot harness.

At present, humans use only about 1 part in 10,000 of the total energy that comes to Earth from the sun. But this ratio is misleading, Kleidon says. Instead, we should be looking at how much useful energy – called “free” energy in the parlance of thermodynamics – is available from the global system, and our impact on that.

Humans currently use energy at the rate of 47 terawatts (TW) or trillions of watts, mostly by burning fossil fuels and harvesting farmed plants, Kleidon calculates in a paper to be published in Philosophical Transactions of the Royal Society. This corresponds to roughly 5 to 10 per cent of the free energy generated by the global system.

“It’s hard to put a precise number on the fraction,” he says, “but we certainly use more of the free energy than [is used by] all geological processes.” In other words, we have a greater effect on Earth’s energy balance than all the earthquakes, volcanoes and tectonic plate movements put together.

Radical as his thesis sounds, it is being taken seriously. “Kleidon is at the forefront of a new wave of research, and the potential prize is huge,” says Peter Cox, who studies climate system dynamics at the University of Exeter, UK. “A theory of the thermodynamics of the Earth system could help us understand the constraints on humankind’s sustainable use of resources.” Indeed, Kleidon’s calculations have profound implications for attempts to transform our energy supply.

Of the 47 TW of energy that we use, about 17 TW comes from burning fossil fuels. So to replace this, we would need to build enough sustainable energy installations to generate at least 17 TW. And because no technology can ever be perfectly efficient, some of the free energy harnessed by wind and wave generators will be lost as heat. So by setting up wind and wave farms, we convert part of the sun’s useful energy into unusable heat.

“Large-scale exploitation of wind energy will inevitably leave an imprint in the atmosphere,” says Kleidon. “Because we use so much free energy, and more every year, we’ll deplete the reservoir of energy.” He says this would probably show up first in wind farms themselves, where the gains expected from massive facilities just won’t pan out as the energy of the Earth system is depleted.

Using a model of global circulation, Kleidon found that the amount of energy which we can expect to harness from the wind is reduced by a factor of 100 if you take into account the depletion of free energy by wind farms. It remains theoretically possible to extract up to 70 TW globally, but doing so would have serious consequences.

Although the winds will not die, sucking that much energy out of the atmosphere in Kleidon’s model changed precipitation, turbulence and the amount of solar radiation reaching the Earth’s surface. The magnitude of the changes was comparable to the changes to the climate caused by doubling atmospheric concentrations of carbon dioxide (Earth System Dynamics, DOI: 10.5194/esd-2-1-2011).

“This is an intriguing point of view and potentially very important,” says meteorologist Maarten Ambaum of the University of Reading, UK. “Human consumption of energy is substantial when compared to free energy production in the Earth system. If we don’t think in terms of free energy, we may be a bit misled by the potential for using natural energy resources.”

This by no means spells the end for renewable energy, however. Photosynthesis also generates free energy, but without producing waste heat. Increasing the fraction of the Earth covered by light-harvesting vegetation – for example, through projects aimed at “greening the deserts” – would mean more free energy would get stored. Photovoltaic solar cells can also increase the amount of free energy gathered from incoming radiation, though there are still major obstacles to doing this sustainably (see “Is solar electricity the answer?”).

In any event, says Kleidon, we are going to need to think about these fundamental principles much more clearly than we have in the past. “We have a hard time convincing engineers working on wind power that the ultimate limitation isn’t how efficient an engine or wind farm is, but how much useful energy nature can generate.” As Kleidon sees it, the idea that we can harvest unlimited amounts of renewable energy from our environment is as much of a fantasy as a perpetual motion machine.

Is solar electricity the answer?

A solar energy industry large enough to make a real impact will require cheap and efficient solar cells. Unfortunately, many of the most efficient of today’s thin-film solar cells require rare elements such as indium and tellurium, whose global supplies could be depleted within decades.

For photovoltaic technology to be sustainable, it will have to be based on cheaper and more readily available materials such as zinc and copper, says Kasturi Chopra of the Indian Institute of Technology, New Delhi.

Researchers at IBM showed last year that they could produce solar cells from these elements along with tin, sulphur and the relatively rare element selenium. These “kesterite” cells already have an efficiency comparable with commercially competitive cells, and it may one day be possible to do without the selenium.

Even if solar cells like this are eventually built and put to work, they will still contribute to global warming. That is because they convert only a small fraction of the light that hits them, and absorb most of the rest, converting it to heat that spills into the environment. Sustainable solar energy may therefore require cells that reflect the light they cannot use.

Congress refuses clean energy, grrr





Robert Redford

Actor, Director, and Environmental Activist

Posted: July 27, 2010 10:13 AM

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for (i = 0; i It’s the Opportunity, Stupid!

A small minority of Senators robbed America of a cleaner, more prosperous future last week. In the middle of the biggest oil disaster in American history, the hottest summer on record, and a war with an oil-rich nation, this group of cynics blocked efforts to pass comprehensive energy and climate legislation. This was the moment brimming with potential for new jobs, a more robust economy and cleaner environment — this bill would have guided America down a profoundly safer and more productive path.

So therefore, the Senate is left to vote on an anemic energy bill of such remarkably limited scope that it could have been passed during the Bush era.

The elected officials who steered this turnaround have abdicated their responsibility to uphold our nation’s best interests, and have shown us, and the world, an America woefully deficient in both leadership and ingenuity.

This was our moment to create two million clean energy jobs here in the United States. This was our moment to outpace China in the clean energy market that will dominate the 21st century. This was our time to slash our oil imports in half. This was our time to confront the perils of climate change, which despite head-in-the sand-denial, is in fact happening.

The American people wanted a home run, not a bunt. A recent CNN poll found that nearly 80 percent of voters believe that reducing oil use and shifting to cleaner energy would make life better for Americans, while a Wall Street Journal poll in June found that an overwhelming majority of people specifically support passing legislation to limit global warming pollution.

Yet a handful of politicians decided they didn’t want to represent the will of the people. Given the chance to invest in American jobs and reduce dangerous pollution, they chose instead, to focus on their own interest and self-preservation.

The Republican Senate leadership has fought against every clean energy and climate measure simply because their political opponents were for it. This was the most shameful partisanship I have seen in my lifetime. We all know who really loses when GOP leaders block progress: American citizens. The economic recession and climate change don’t care which party you are in — they will make life harder for everyone until we put the right solutions in place.

But the GOP wasn’t the only force acting on its own behalf. A handful of moderate Democrats were so worried about being tarred by the Tea Party or losing reelection campaigns that they failed to show their support for clean energy and climate legislation — even those who are on record saying that we must fight global warming. When elected officials act as bystanders to a crisis, they reveal their deep cowardice.

We can’t forget that Big Oil and Big Coal reached deep into their pockets to inspire politicians to block climate action. Their undue influence in our nation’s politics has once again placed the desires of polluters above the interests of all Americans.

Stronger leadership from the White House could have helped burst through political obstructions. President Obama has certainly done more than any other president to advance clean energy, yet he never seemed to roll up his sleeves, bring lawmakers to the table, and work to rally the American public behind it. If he thought his move earlier this year to approve new offshore oil drilling for the first time in decades would pay off last week in the form of GOP support for this bill, I guess he got his answer.

This is one of the many times when average citizens may be ahead of our leaders. All of us who want to generate jobs, reduce hazardous pollution, and strengthen our nation’s security need to make our voices heard. We should praise those senators who represented our best interests and hold accountable those who looked out only for their own.

I remember the last time our nation came this close to embracing clean energy — back in the late 1970s. I hope my children don’t have to wait another 35 years to seize the moment once again, because that moment, that opportunity might not be there.