So what has changed? Aside from growing concern about climate change and a surge in the oil price, the big difference is that battery technology is getting a lot better. Rechargeable lithium-ion batteries, which helped to make the mobile-phone revolution possible in the past decade, are now expected to power the increasing electrification of the car. “They are clearly the next step,” says Mary Ann Wright, the boss of Johnson Controls-Saft Advanced Power Solutions, a joint venture that recently opened a factory in France to produce lithium-ion batteries for hybrid vehicles.

According to Menahem Anderman, a consultant based in California who specialises in the automotive-battery market, more money is being spent on research into lithium-ion batteries than all other battery chemistries combined. A big market awaits the firms that manage to adapt lithium-ion batteries for cars. Between now and 2015, Dr Anderman estimates, the worldwide market for hybrid-vehicle batteries will more than triple, to $2.3 billion. Lithium-ion batteries, the first of which should appear in hybrid cars in 2009, could make up as much as half of that, he predicts.

Compared with other types of rechargeable-battery chemistry, the lithium-ion approach has many advantages. Besides being light, it does not suffer from any memory effect, which is the loss in capacity when a battery is recharged without being fully depleted. Once in mass production, large-scale lithium-ion technology is expected to become cheaper than its closest rival, the nickel-metal-hydride battery, which is found in the Prius and most other hybrid cars.

Still, the success of the lithium-ion battery is not assured. Its biggest weakness is probably its tendency to become unstable if it is overheated, overcharged or punctured. In 2006 Sony, a Japanese electronics giant, had to recall several million laptop batteries because of a manufacturing defect that caused some batteries to burst into flames. A faulty car battery which contains many times more stored energy could trigger a huge explosion—something no car company could afford. Performance, durability and tight costs for cars are also much more stringent than for small electronic devices. So the quest is under way for the refinements and improvements that will bring lithium-ion batteries up to scratch—and lead to their presence in millions of cars.

Alessandro Volta, an Italian physicist, invented the first battery in 1800. Since then a lot of new types have been developed, though all are based on the same principle: they exploit chemical reactions between different materials to store and deliver electrical energy.

Back to battery basics

A battery is made up of one or more cells. Each cell consists of a negative electrode and a positive electrode kept apart by a separator soaked in a conductive electrolyte that allows ions, but not electrons, to travel between them. When a battery is connected to a load, a chemical reaction begins. As positively charged ions travel from the negative to the positive electrode through the electrolyte, a proportional number of negatively charged electrons must make the same journey through an external circuit, resulting in an electric current that does useful work.

Some batteries are based on an underlying chemical reaction that can be reversed. Such rechargeable batteries have an advantage, because they can be restored to their charged state by reversing the direction of the current flow that occurred during discharging. They can thus be reused hundreds or thousands of times. According to Joe Iorillo, an analyst at the Freedonia Group, rechargeable batteries make up almost two-thirds of the world’s $56 billion battery market. Four different chemical reactions dominate the industry—each of which has pros and cons when it comes to utility, durability, cost, safety and performance.

The first rechargeable battery, the lead-acid battery, was invented in 1859 by Gaston Planté, a French physicist. The electrification of Europe and America in the late 19th century sparked the use of storage batteries for telegraphy, portable electric-lighting systems and back-up power. But the biggest market was probably electric cars. At the turn of the century battery-powered vehicles were a common sight on city streets, because they were quiet and did not emit any noxious fumes. But electric cars could not compete on range. In 1912 the electric self-starter, which replaced cranking by hand, meant that cars with internal-combustion engines left electric cars in the dust.

Nickel-cadmium cells came along around 1900 and were used in situations where more power was needed. As with lead-acid batteries, nickel-cadmium cells had a tendency to produce gases while in use, especially when being overcharged. In the late 1940s Georg Neumann, a German engineer, succeeded in fine-tuning the battery’s chemistry to avoid this problem, making a sealed version possible. It started to become more widely available in the 1960s, powering devices such as electric razors and toothbrushes.

For most of the 20th century lead-acid and nickel-cadmium cells dominated the rechargeable-battery market, and both are still in use today. Although they cannot store as much energy for a given weight or volume as newer technologies, they can be extremely cost-effective. Small lead-acid battery packs provide short bursts of power to starter motors in virtually all cars; they are also used in large back-up power systems, and make up about half of the worldwide rechargeable-battery market. Nickel-cadmium batteries are used to provide emergency back-up power on planes and trains.

Time to change the batteries

In the past two decades two new rechargeable-battery types made their commercial debuts. Storing about twice as much energy as a lead-acid battery for a given weight, the nickel-metal-hydride battery appeared on the market in 1989. For much of the 1990s it was the battery of choice for powering portable electronic devices, displacing nickel-cadmium batteries in many applications. Toyota picked nickel-metal-hydride batteries for the new hybrid petrol-electric car it launched in 1997, the Prius.

Nickel-metal-hydride batteries evolved from the nickel-hydrogen batteries used to power satellites. Such batteries are expensive and bulky, since they require high-pressure hydrogen-storage tanks, but they offer high energy-density and last a long time, which makes them well suited for use in space. Nickel-metal-hydride batteries emerged as researchers looked for ways to store hydrogen in a more convenient form: within a hydrogen-absorbing metal alloy. Eventually Stanford Ovshinsky, an American inventor, and his company, now known as ECD Ovonics, succeeded in creating metal-hydride alloys with a disordered structure that improved performance.

Adapting the nickel-metal-hydride battery to the automotive environment was no small feat, since the way batteries have to work in hybrid cars is very different from the way they work in portable devices. Batteries in laptops and mobile phones are engineered to be discharged over the course of several hours or days, and they only need to last a couple of years. Hybrid-car batteries, on the other hand, are expected to work for eight to ten years and must endure hundreds of thousands of partial charge and discharge cycles as they absorb energy from regenerative braking or supply short bursts of power to aid in acceleration.

Lithium-ion batteries evolved from non-rechargeable lithium batteries, such as those used in watches and hearing aids. One reason lithium is particularly suitable for batteries is that it is the lightest metal, which means a lithium battery of a given weight can store more energy than one based on another metal (such as lead or nickel). Early rechargeable lithium batteries used pure lithium metal as the negative-electrode material, and an “intercalation” compound—a material with a lattice structure that could absorb lithium ions—as the positive electrode.

The problem with this design was that during recharging, the metallic lithium reformed unevenly at the negative electrode, creating spiky structures called “dendrites” that are unstable and reactive, and can pierce the separator and cause an explosion. So today’s rechargeable lithium-ion batteries do not contain lithium in metallic form. Instead they use materials with lattice structures for both positive and negative electrodes. As the battery discharges, the lithium ions swim from the negative-electrode lattice to the positive one; during recharging, they swim back again. This to-and-fro approach is called a “rocking chair” design.

The first commercial lithium-ion battery, launched by Sony in 1991, was a rocking-chair design that used cobalt oxide for the positive electrode, and graphite (carbon) for the negative one. In the early 1990s, such batteries had an energy density of about 100 watt-hours per litre. Since then engineers have worked out ways to squeeze more than twice as much energy into a battery of the same size, in particular by reducing the width of the separator and increasing the amount of active electrode materials.

The high energy-density of lithium-ion batteries makes them the best technology for portable devices. According to Christophe Pillot of Avicenne Développement, a market-research firm based in Paris, they account for 70% of the $7 billion market for portable, rechargeable batteries. But not all lithium-ion batteries are alike. The host structures that accept lithium ions can be made using a variety of materials, explains Venkat Srinivasan, a scientist at America’s Lawrence Berkeley National Laboratory. The combination of materials determines the characteristics of the battery, including its energy and power density, safety, longevity and cost. Because of this flexibility, researchers hope to develop new electrode materials that can increase the energy density of lithium-ion batteries by a factor of two or more in the future.

Hooked on lithium

The batteries commonly used in today’s mobile phones and laptops still use cobalt oxide as the positive electrode. Such batteries are also starting to appear in cars, such as Tesla’s Roadster. But since cobalt oxide is so reactive and costly, most experts deem it unsuitable for widespread use in hybrid or electric vehicles.

So researchers are trying other approaches. Some firms, such as Compact Power, based in Troy, Michigan, are developing batteries in which the cobalt is replaced by manganese, a material that is less expensive and more stable at high temperatures. Unfortunately, batteries with manganese-based electrodes store slightly less energy than cobalt-based ones, and also tend to have a shorter life, as manganese starts to dissolve into the electrolyte. But blending manganese with other elements, such as nickel and cobalt, can reduce these problems, says Michael Thackeray, a senior scientist at America’s Argonne National Laboratory who holds several patents in this area.

In 1997 John Goodenough and his colleagues at the University of Texas published a paper in which they suggested using a new material for the positive electrode: iron phosphate. It promised to be cheaper, safer and more environmentally friendly than cobalt oxide. There were just two problems: it had a lower energy-density than cobalt oxide and suffered from low conductivity, limiting the rate at which energy could be delivered and stored by the battery. So when Yet-Ming Chiang of the Massachusetts Institute of Technology and his colleagues published a paper in 2002 in which they claimed to have dramatically boosted the material’s conductivity by doping it with aluminium, niobium and zirconium, other researchers were impressed—though the exact mechanism that causes the increase in performance has since become the subject of a heated debate.

Dr Chiang’s team published another paper in 2004 in which they described a way to increase performance further. Using iron-phosphate particles less than 100 nanometres across—about 100 times smaller than usual—increases the surface area of the electrode and improves the battery’s ability to store and deliver energy. But again, the exact mechanism involved is somewhat controversial.

The iron-phosphate technology is being commercialised by several companies, including A123 Systems, co-founded by Dr Chiang, and Phostech Lithium, a Canadian firm that has been granted exclusive rights to manufacture and sell the material based on Dr Goodenough’s patents. At the moment the two rivals are competing in the market, but their fate may be decided in court, since they are fighting a patent-infringement battle.

The quest for the perfect battery

Johnson Controls and Saft, which launched a joint venture in 2006, are taking a different approach, in which the positive electrode is made using a nickel-cobalt-aluminium-oxide. John Searle, the company’s boss, says batteries made using its approach can last about 15 years. In 2007 Saft announced that Daimler had selected its batteries for use in a hybrid Mercedes saloon, due to go on sale in 2009. Other materials being investigated for use in future lithium-ion batteries include tin alloys and silicon.

CorbisLook, no exhaust pipe

At this point, it is hard to say which lithium-ion variation will prevail. Toyota, which is pursuing its own battery development with Matsushita, will not say which chemistry it favours. GM is also hedging its bets. The company is testing battery packs from both A123 Systems and Compact Power for the Chevy Volt (pictured), a forthcoming plug-in hybrid that will have an all-electric range of 40 miles and a small internal-combustion engine to recharge its battery when necessary. To ensure that the Volt’s battery can always supply enough power and meet its targeted 10-year life-span, it will be kept between 30% and 80% charged at all times, says Roland Matthe of GM‘s energy-storage systems group.

GM hopes to start mass-production of the Volt in late 2010. That is ambitious, since the Volt’s viability is dependent on the availability of a suitable battery technology. “It’s either going to be a tremendous victory, or a terrible defeat,” says James George, a battery expert based in New Hampshire who has followed the industry for 45 years.

“We’ve still got a long way to go in terms of getting the ultimate battery,” says Dr Thackeray. Compared with computer chips, which have doubled in performance roughly every two years for decades, batteries have improved very slowly over their 200-year history. But high oil prices and concern over climate change mean there is now more of an incentive than ever for researchers to join the quest for better battery technologies. “It’s going to be a journey”, says Ms Wright, “where we’re going to be using the gas engine less and less.”

Biofuel from trees a looming disaster

The promise being made is that wood can produce fuels to run our cars. A few years ago we were told corn, rapeseed, sugar, oil palm, soy and various other crops could be grown for biofuels while providing energy security and reducing greenhouse emissions. The reality has been far different with globally surging food prices, loss of rainforests and other important habitats, further depletion and poisoning of aquifers, and rampant human rights abuses — all for little or no greenhouse gas emission reduction.

So called "second generation biofuels", including the use of woody biomass, is being given the same unthinking, ecologically bereft hype. I will focus upon the idea that a wide variety of woody plant materials — including both waste and planted woody crops — should be the basis of a cellulosic ethanol industry. Creating ethanol is trickier than with agrofuels, the cellulose more difficult to break down, but clearly it is possible to produce liquid fuels from woody biomass. But what of associated social and ecological issues that are again being ignored?

Second generation biofuels based upon woody biomass will clearly be an unmitigated disaster. As with agrofuels, a cellulosic ethanol industry will indirectly destroy forests and lead to more costly food by increasing land pressures upon natural forests and agricultural crop lands. We can expect more vast, lifeless, toxic and water dependent monocultures of genetically modified Frankentrees on stolen deforested lands at a net carbon loss. And the biofuels will be sold to us as a green product, perhaps certified as "well-managed" by WWF, FSC, and other forest sell-outs.

Global forest crisis the fundamental ecological problem

Forest waste is a euphemism for the materials left over when industrial forestry decimates a forest. The branches, bark, saw dust, etc. represent nutrients that are best returned to virtually mined soils to make new forests. There is certainly not enough such "waste" lying around unused to power industrial society. Just what the world’s beleaguered natural old-growth and regenerating forest ecosystems need, another potentially limitless draw upon their growth, diversity and regeneration.

Once the infrastructure is in place to toss wood into vast choppers and have energy come out the other end, how long until meager switch grass harvests are supplemented with natural forest clearance? Let’s skip the step of clearing rainforests to plant crops and just toss the chopped up liquefied rainforests directly into our gas tank instead. The use of wood biomass from natural forests is already occurring on a limited scale and will be ramped up. Such is the promise of cellulosic ethanol.

Natural forests and other habitats provide a thin layer of biological life that shields and acts in concert with other aspects of the Earth System to make advanced life possible. This human habitat is endangered, devastated in short order by the human locust. All major environmental crises are entwined, but my observation is that clearing of terrestrial ecosystems — that is dismantling human habitats as resources to allow unsustainable growth — is the crux of the human dilemma.

As if the world’s forests, land base, ecosystems and habitats do not have enough demands upon them already, let us try to use them to power seven billion consumers in their drive to each have it all. Think this a needlessly harsh appraisal? Name one time the global economic system has demonstrated self-control in matching growth to underlying resources. Biofuels based upon wood must be rejected now, before it begins, to avoid the next ecological catastrophe. Given the scale of human energy demands and dismal state of global ecosystems, this one may prove fatal.

Time only for ambitious, sufficient global ecological responses

The Earth system is perilously close to failure and cannot stand more environmental solutions based upon greater and more intensive resource use for current, much less increased, human population and consumption. Most want an energy panacea that allows endless procreation and economic growth. None are to be had. There is a finite amount of energy that can be taken from, and waste put into, the global biosphere before it becomes uninhabitable. And we are reaching or have passed that point.

It is imperative that we embrace an environmental agenda based upon what is actually needed to maintain and restore ecological systems upon which all life depends. It is too late to put our efforts into anything else than the full package of societal and personal change necessary to maintain the biosphere. There are no solutions worth pursuing at this late date other than those that are ecologically sufficient. Anything less is more of the same disease that is assuredly destroying being.

Regular readers will know I have identified several major societal changes that could be implemented now at considerable but affordable cost and would make major headway in saving creation. These include immediately ending the use of coal that emits waste in the atmosphere; ceasing industrial clearance of natural habitats including ancient forests; investing major sums in renewable energy, energy conservation and efficiency; and providing incentives to reduce global population and sum consumption (more at http://www.ecoearth.info/ssi/ ).

These and other rigorous and sufficient measures will be pursued, or global ecological collapse is unavoidable. If part of your shtick is we can cut our forests, burn our fossil fuels, and continue to grow endlessly; you are the disease eating the Earth. Change sides and become part of the cure by rejecting reformist quick fixes such as biofuel from food and trees in favor of an environmental sufficiency agenda. Or we can all die looking for an easy way to have it all at the Earth’s expense.

Nanling Reserve is one of scores of fragile ecosystems, from Anhui Province in the east to Guangdong Province in the south, that took a beating from storms in late January and early February that set records for snow- fall and low temperatures in some areas. Last week, China’s State Forestry Administration (SFA) announced that the storms damaged 20.86 million hectares-one-tenth of China’s forests and plantations-roughly equivalent to the number of hectares that were reforested between 2003 and 2006. SFA pegs the losses at $8 billion. "The severe storms did a massive amount of harm," says Li Jianqiang, a plant taxonomist at Wuhan Botanical Garden. "This scale of damage has never happened before."

He Kejun and others say it will take decades for the hardest-hit ecosystems to recover. The ecological and economic toll rivals that of devastating floods along the Yangtze River in 1998 that inundated 25 million hectares of farmland. For broadleaf evergreen forests, "this is bigger than the Yangtze disas- ter. It’s unique in the history of south China," says Ren Hai, an ecologist with the South China Botanical Garden (SCBG) in Guangzhou. SFA and other agencies have dispatched scientists to take stock and formu- late restoration plans. "The government is acting very, very fast," says Ren.

In southeastern China’s worst winter in 5 decades, snow and ice knocked out power and paralyzed roads and rail lines at the height of the year’s busiest travel season-the Spring Festival, when many Chinese return to their hometowns. The storms pummeled 21 of 33 provinces and regions, claiming 129 lives. Some 485,000 homes were destroyed and another 1.6 million damaged, displacing nearly 1.7 million people, accord- ing to central government statistics. Agricul- ture officials estimate that 69 million live- stock-mostly chickens and ducks-froze to death. Storm-related losses exceed $21 bil- lion. As Sciencewent to press, electricity had still not been restored to some remote areas. Scenes of scrums at train stations and vehi- cles adrift on highways were splashed across the news in China and abroad last month.

Meanwhile, outside the spotlight, an ecologi- cal calamity was unfolding. In Jiangxi Province, for example, entire bamboo forests were reduced to matchsticks; fast-growing bamboo can regenerate in several years. In Guangdong, officials estimate that more than 700,000 hectares of forest and plantations are damaged severely, with losses approaching $1 billion. Other provinces enduring extensive forest damage are Anhui, Guangxi, Guizhou, Hubei, Hunan, and Sichuan

The carnage was not limited to natural ecosystems. "Exotic species were harmed more than native species," says Ren. In north- ern Guangdong Province, plantations of slash pine (Pinus elliottii), an import from the southern United States, splintered under wet snow, and extensive stands of Australian gum trees "are almost all going to die," Ren predicts. At Wuhan Botanical Garden in Hubei Province, the roof of a greenhouse housing Asia’s largest assemblage of aquatic plants caved in under heavy snow. "A unique collection has been lost," says Wuhan botanist Li Xiaodong.

SCBG scientists maintain long-term experimental plots at Nanling that will allow them to gauge ecosystem damage and recov- ery. At the moment, the picture is bleak. Nanling’s entire forest between 500 meters and 1300 meters in elevation was wiped out, says He. "Before the storm, we could hear birds singing in the reserve. Now it is mostly silent," he says. Many bai xian, or silver pheasants-Guangdong’s official bird- succumbed to the severe weather, and carcasses litter Nanling’s trails, says He. One worry, he says, is that epidemics will erupt this spring in the storm-sapped animal popu- lations and among migratory birds.

With support from Guangdong Province’s government, SCBG plans to send teams of sci- entists to several of the most devastated forests to survey damage and to set up test plots that will track everything from species compo- sition to the susceptibility of the degraded forests to insect pests and fires. The storm damage lends urgency to a new national strategy for plant conservation released last week by SFA, the Chinese Academy of Sciences, and the State Envi- ronmental Protection Agency. Under the manifesto, crafted with help from Botanic Gardens Conservation International, a Richmond, U.K., nonprofit, China has pledged to launch a nationwide survey of species and habitats, construct a national herbarium, crack down on illegal logging, and establish by 2010 a system to monitor and protect China’s 31,000 plant species, more than half of which are native.

As damage assessments proceed, SFA has established a disaster relief technology group and will hold an emergency meeting later this month to plan for restoration. Botanical gardens are doing their part, too. "We must work hard to save vegetation and lessen the extent of damage," says Ren. "We want to find a way to help natural ecosystems recover with minimal human disturbance." That is a tricky balancing act. At Nan- ling, managers are barring local residents from entering to remove downed timber. Although salvage logging could reduce wildfire risk, it could exacerbate erosion, further degrading ecosystems. The bulk of the restoration work is likely to focus on economic recovery: rehabilitation of plan- tations. The storm’s aftermath should also spur long-term research on plant cold toler- ance, says Li Jianqiang.

The immediate task is picking up the pieces after the worst winter in recent memory. "We cherish our endangered species," says Li. But for some of the precious plants at Wuhan Botanical Garden and in southern China’s battered reserves, he says, "there is nothing we can do to save them." -RICHARD STONE With reporting by Li Jiao in Beijing.

Severe winter storms that damaged and knocked over a tenth of China’s forests in recent weeks should have a relatively neutral impact on Sino-Forest Corp. (SNOFF.PK), the Canadian-listed Chinese plantation owner, Dundee Securities analyst Richard Kelertas wrote in a recent research note. (more…)