Wednesday, 15 August 2007

Paper battery offers future power

Flexible paper batteries could meet the energy demands of the next generation of gadgets, says a team of researchers.
They have produced a sample slightly larger than a postage stamp that can release about 2.3 volts, enough to illuminate a small light.

But the ambition is to produce reams of paper that could one day power a car.

"The devices we're making are only a few inches across. We would have to scale up to sheets of newspaper size to make it commercially viable," he said. But at that scale, the voltage could be large enough to power a car, he said.

However, carbon nanotubes are very expensive, and batteries large enough to power a car are unlikely to be cost effective.

"I'm a strong enthusiast of electric vehicles, but it is going to take time to bring the costs down," said Professor Sperling.

But Professor Linhardt said integrated devices, like the paper battery, were the direction the world was moving.

"They are ultimately easier to manufacture, more environmentally friendly and usable in a wide range of devices," he said.

The ambition is to produce the paper battery using a newspaper-type roller printer.

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Tuesday, 14 August 2007

energy policy lacking

Environmental groups and the renewables industry yesterday urged Gordon Brown to overhaul government energy policy if Britain is to have any hope of meeting its EU targets to combat climate change.
Green groups argue that Britain could achieve 20% by 2020 if it really wanted to. Adam Bruce, chairman of the British Wind Energy Association, said: "It is simply wrong for civil servants to now suggest that the 20% EU target cannot be met - the UK wind energy industry is confident that it can meet these new renewable objectives if the government takes the necessary measures to support it."

He said 40% of the EU's entire potential wind energy blows across Britain, but a lack of government action was preventing its proper exploitation.

Andrew Simms, head of the New Economics Foundation, said: "If renewable energy in Britain had enjoyed for decades the blank cheque that was written for the nuclear industry, today most of our electricity would be coming from a combination of wind, wave and solar power.

"If the DBERR continues to undermine progress toward the new, renewable energy economy it will potentially do even more damage than a leaky reactor."

The energy minister, Malcolm Wicks, told BBC radio that the government was on course to meet its own target of generating 15% of Britain's electricity from renewable sources by 2015. He acknowledged the EU target was more demanding.
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Four in five homes using energy-saving bulbs

The extent of the green revolution in Britain’s households will be revealed today with figures showing that more than 80 per cent of people believe they have a “duty” to recycle household waste.

The findings, to be published by the respected Office of National Statistics, also show a dramatic increase in the number of people who say they have at least one energy-saving light bulb in their homes.

The survey found that 81 per cent of people say they have at least one low-energy light bulb at home compared to just over 30 per cent a few years ago.
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Solar cells that can be printed

The development of a new solar cell may provide consumers a way to harness solar rays as a form of renewable energy, inexpensively.

Researchers at the New Jersey Institute of Technology (NJIT) have developed an inexpensive solar cell that can be painted or printed on flexible plastic sheets.

The new solar cells use a carbon nanotubes complex, which is a molecular configuration of carbon in a cylindrical shape. These nanotubes are about 50,000 times smaller than a human hair.
"The process is simple," said lead researcher and author Dr. Somenath Mitra, professor and acting chair of NJIT's department of chemistry and environmental sciences.

He foresees the day when consumers will even be able to print sheets of these solar cells with inexpensive home-based inkjet printers.

"Consumers can then slap the finished product on a wall, roof or billboard to create their own power stations," Mitra said.

How they work

While the new solar cells are very thin, just one nanotube can conduct current better than any conventional electrical wire, Mitra said.

"Actually, nanotubes are significantly better conductors than copper," he added. Mitra and his research team took the carbon nanotubes and combined them with tiny carbon "buckyballs" (carbon molecules in a hollow sphere configuration), to form snake-like structures, also called polymers.

Buckyballs are able to trap electrons, although they can't make electrons flow.

When the polymers are exposed to sunlight, and the buckyballs will grab the electrons.

The nanotubes, on the other hand, behave like copper wires, and so are able to make the electrons flow, Mitra explained.

"Using this unique combination in an organic solar cell recipe can enhance the efficiency of future painted-on solar cells," Mitra said.

"Someday, I hope to see this process become an inexpensive energy alternative for households around the world."

Renewable energy challenges

Harvesting energy directly from abundant solar radiation using solar cells is becoming increasingly for future global energy strategy, Mitra said.

But when it comes to harnessing renewable energy, challenges remain.

Expensive, large-scale infrastructure such as windmills (for wind power) or dams (for hydroelectric power) are necessary to drive renewable energy sources.

Even when solar power is being considered, there is the challenge of obtaining enough materials. Purified silicon, already in high demand for making computer chips, is a core material for fabricating conventional solar cells.

Moreover, the processing of purified silicon is beyond the capabilities of most consumers, Mitra notes.

"Developing organic solar cells from polymers, however, is a cheap and potentially simpler alternative," he said.

When contacted by In.Tech, Mitra claimed the process is commercially viable.

"We foresee a great deal of interest in our work because solar cells can be inexpensively printed or simply painted on exterior building walls and rooftops.

"Imagine some day driving in your hybrid car with a solar panel painted on the roof, which is producing electricity to drive the engine," Mitra said.

However, he concedes that the NJIT cells need improvement in the area of energy conversion efficiency, a measure of the power converted from absorbed light.

The NJIT cells currently run at only around 1% efficiency, compared to more than 25% efficiency for the best conventional solar cells.

"We should be able to improve (the cell efficiency) as we do more research, but the advantage is in the low capital investment required for this technology, which is significantly lower than for conventional solar cells."

Current silicon-based solar cells in use are relatively complex; they share many of the same processing and manufacturing techniques used for other semiconductor devices such as processors and memory chips.

Mitra's work was first published in the June edition of the Journal of Materials Chemistry.

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