Tag Archives: surface transport

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

Fleet of hybrid airships to conquer Arctic

One Per Cent: Fleet of hybrid airships to conquer Arctic.

Joel Shurkin, contributor

HAV2.jpg

(Image: HAV)

Travelling through the Arctic is notoriously difficult and climate change is making it even harder. But there is a way to rise above the problem: the latest generation of lighter-than-air vehicles. Canadian company Discovery Air has signed a contract with the UK’s Hybrid Air Vehicles (HAV) to buy around 45 new hybrid air vehicles. These aircraft will be used across Canada’s Northwest Territories.

Whether taking out lumber from the forests or helping people access remote villages, transportation in Arctic Canada can be extrememly daunting. Most transportation is either by air, which is expensive, by boat, or by ice road. Rising winter temperatures, due to climate change, are likely to make Canada’s ice roads less stable and reduce the amount of time in winter in which they can safely be used.

Gordon Taylor, marketing director for HAV, says the vessels are technically neither airships nor blimps. While they do make use of non-explosive helium for lift, they also get substantial lift from the aerodynamic design of the fuselage.

HAV already has a major contract for hybrid vehicles with the US Defence Department for long-endurance surveillance vessels.

The vessels Discovery Air has ordered are HAV’s model 366, which Taylor says can carry 50 tonnes if they take off horizontally like an airplane and around 30 tonnes if they take off vertically. Not even the largest helicopters in the world can match that, explains Taylor.

One hundred and ten metres long, the vessels can reach altitudes of almost 3000 metres and can take off and land almost anywhere. The cargo will fit in the fuselage for very long trips or can hang beneath the ship for shorter ones. Later models can also be flown remotely.

China train crash blamed on signal design flaw

BBC News – China train crash: Signal design flaw blamed.

Serious flaws in a signalling system caused a fatal collision on China’s high-speed rail network, officials say.

Thirty-nine people died when a train ran into the back of another which had stalled on a viaduct near Wenzhou after lightning cut its power supply.

The system “failed to turn the green light into red”, said An Lusheng, head of the Shanghai Railway Bureau.

Chinese Premier Wen Jiabao, who has been visiting the crash site, vowed to “severely punish” those responsible.

Wen Jiabao held the news conference under the viaduct where six of these carriages came off during Saturday’s collision. He stressed that safety would be the absolute priority as China built its huge high-speed network. It is already the second-largest in the world and is set to be expanded.

Wen Jiabao, often referred to as “Granpa Wen”, is the soft face of the party. When there is a crisis or an accident like this, Premier Wen is the man with the common touch who deals with the public.

There was pressure on him to visit the scene. When asked why it took him so long to get to Wenzhou, he said he had been ill and his doctors had not wanted him to travel but he felt it was very important.

But still there is public anger here about the crash, which has raised safety questions about the whole of China’s high-speed network.

“The country’s development is for the people, so the most important thing is people’s lives,” Mr Wen told reporters at the scene.

“No matter if it was a mechanical fault, a management problem, or a manufacturing problem, we must get to the bottom of this.

“If corruption was found behind this, we must handle it according to law and will not be soft.”

Mr Wen earlier promised to take steps to improve safety on the high-speed rail network – one of the government’s flagship projects which it hopes highlights China’s development.

Six carriages derailed and four fell between 20m to 30m (65ft to 100ft) from the viaduct after Saturday night’s crash, which injured nearly 200 people.

The accident came just four years after the country’s first high-speed trains began operating.

Rail experts had warned against the rush to build the world’s longest and fastest high-speed rail network in record time amid safety concerns.

There are allegations that corners were cut during construction because of corruption, raising questions about infrastructure across the country.

This photo taken on July 24, 2011 shows workers clearing wreckage of mangled carriages after a Chinese high-speed train derailed Four carriages plunged from the viaduct

The BBC’s Martin Patience in Wenzhou says it is difficult to get to the truth because of a lack of transparency and accountability.

There is a real sense that things are perhaps being built too quickly and that safety is being jeopardised in the process, our correspondent says.

‘Public relations disaster’

Mr Wen’s visit to the crash scene comes amid growing public outrage at the accident.

Internet users and relatives of the victims have been angered by the government’s apparent unwillingness to answer questions about the crash.

This has led to accusations of government “arrogance”, amid suspicions of a cover-up.

The authorities have moved quickly to stem media coverage, urging reporters to focus on “extremely moving” stories, saying the overall theme should be “great love in the face of great disaster”.

Map

Chinese media have been ordered not to question the official line on the accident, but several newspapers have published editorials criticising the railway ministry.

In an unusually scathing editorial published in both its English and Chinese versions, the state-run Global Times on Wednesday said the government’s handling of the accident aftermath was a “public relations disaster”.

“The relationship between the government and the public is like that of a ship and water. Water can keep the ship afloat or sink it,” it said.

Some relatives of victims, who include two Americans and an Italian, have reportedly refused compensation and instead demanded to be given answers.

The accident is seen as a blow to China’s hopes of selling trains abroad in a bid to become a high-tech exporter.

Shares in Chinese rail and train builders have fallen sharply since the crash.

A Warming World Could Add Billions to Shipping Costs

A Warming World Could Add Billions to Shipping Costs – ScienceNOW.

WASHINGTON, D.C.—Climate change already stands to wreak huge financial damage by inundating coastal cities and harming human health. Now, researchers have added a surprising victim to the toll: ships. In a session here today at the annual meeting of the American Association for the Advancement of Science (which publishes ScienceNOW), a scientist said that climate change will stimulate the growth of barnacles and other ship-clinging creatures, potentially adding billions to the cost of worldwide shipping.

As anyone with a boat knows, many sorts of marine life can attach themselves to a hull below the waterline. On a large ship, the weight of such hitchhikers—everything from algae to barnacles to small colonies of coral—can weigh as much as 10 tons, says marine ecologist Susan Williams of the University of California, Davis, Bodega Marine Laboratory in Bodega Bay. The costs of these hull-fouling stowaways are substantial: According to one study, the U.S. shipping industry spends more than $36 billion each year in added fuel costs to overcome the drag induced by clinging marine life or for anti-fouling paint that prevents that life from hitching a ride in the first place. And that figure doesn’t include the cost to regularly scrape a hull smooth, which costs approximately $4.50 for every square foot of hull surface.

In the future, those costs could rise substantially, says Williams. In lab tests for which seawater was warmed 3.5°C above today’s average—a scenario that represents water temperatures expected in the year 2100—organisms in a typical community of hull-clinging creatures grew twice as fast as they do under today’s conditions. They not only grow more quickly in the warmer water but also grew to form thicker layers.

As a result, maintenance will likely be required more often in the future, boosting operational costs even further. In fact, recent warming may already have increased the need for routine hull scraping, says Williams. Ten years ago, boat owners in the marina where she lives typically scraped their boats only once every 3 months. Now, she notes, they need to perform such maintenance on a monthly basis.

See our complete coverage of the 2011 AAAS annual meeting in Washington, D.C.