SOLAR ENERGY

SOLAR ENERGY GENERATION:

A range of new solar technologies from compact chargers, roof tiles to solar farms are contributing towards efficient energy by harnessing green power on mass scale. Consumers are also turning to sun's energy at the household level to generate their own electricity using traditional and new materials.

A new generation of portable solar chargers can plug straight into a laptop and provide up to a quarter of its power needs while in use.The Solargorilla charger by Powertraveller, for instance, can also level out the electrical spikes caused when clouds obscure the sun.

Jerry Ranger, head of Powertraveller, says the charger is able to convert a high percentage of the sunlight's energy in a more compact way than previous devices.

"You can get the power output if you get a massive great big panel but clearly that's impractical so we've needed to get it down to a size that's portable," he told BBC."So previously we had around 15% efficiencies, we're now on the verge of getting 20%, and within the next 18 months we expect to deliver around 22% efficiencies," he explained.Consumers can currently use portable panels only for charging up small devices such as phones or music players.Powertraveller plans to launch a portable four-panel folding array that can run a laptop and charge the battery at the same time.Planned for spring 2010, it will be the first commercial device to offer AC or DC outputs.Consumers are also increasingly exploiting the sun's energy in the home.

Panel power

There has been a steady growth in small-scale electricity production at home in recent years. In 2008 there was a 


considerable jump – the number of people looking to generate their own electricity doubled in just 12 months.

Traditionally, homes have harnessed power from the sun through conventional solar panels, but an American company has developed what it hopes is the next generation of panel power.

SRS Energy has created "sole power" tiles, which are coated with thin-film flexible photovoltaic cells. The roof tiles are a dark blue colour to maximise the absorption of sunlight, and will be available from spring 2010.The tiles are an example of how technology, in the form of new polymers and coatings, has the potential to increase the amount of energy that can be adapted from the sun.For years most solar cells struggled to harness just one sixth of the sun's energy.But newer materials are helping solar panels become more efficient, according to Professor Tony Day, director of the Centre for Efficient and Renewable Energy in Building, London South Bank University."Laboratory tests are showing we can get to module efficiencies of about 22-23%, with traditional materials," he said."The next generation of materials it looks in the laboratory to be moving towards 30%, and in some specialist applications even 40%," he added.

Light tunnels

The British Columbia Institute of Technology decided to dispense with expensive solar panels and test out a new system in one of its buildings.The Canadian university installed sun canopies in the roof to direct light through tunnels in the ceilings above every floor.Each tunnel has a highly reflective coating to bounce the light round the building. When a cloud goes over, the fluorescent lights kick in to maintain brightness until the sun returns.Allen Upward, a research engineer at the University of British Columbia (UBC) said the system is seven times more effective than traditional solar methods."As a system for lighting a building, it's far more effective than using solar panels to generate electricity and then turning that electricity back into light," he explained.The sun's potential remains under-exploited - the Earth gets 5,000 times more energy from the sun than we use in electricity. Solar farms have been popping up all over the world in an attempt to harness the green power on a mass scale.One solar farm in southern Spain has swapped panels for mirrors and is using the sun's heat rather than brightness to create electricity.

Heat power

Just outside Seville, hundreds of mirrors track the sun as it crosses the sky and reflect their beams to a single point at the top of a tower.The intense heat is used to boil water and create steam to power a turbine - which creates electricity.Engineer Valerio Fernandez, at Abengoa which runs the solar farm, says the resulting heat is the equivalent of 4,000 times the power of direct sunlight."With this amount of energy we can generate very high temperatures, about 2,000 degrees Celsius," he said.A consortium of 12 European businesses plans to build a huge solar project in the Sahara desert.Desertec Industrial Initiative plans to produce solar-generated electricity with a vast network of power plants and transmission grids across North Africa and the Middle East. It aims to supply Europe with 15% of its energy needs by 2050.The plan has the backing of huge companies including Deutsche Bank, Siemens - and needs $500bn (£303bn) of investment.But some solar experts are sceptical."Part of the problem with the Desertec project is that we are asking somebody else if we can lease their land so we can generate electricity to keep the lights on in Europe," said Prof Tony Day.

"I think that there are political issues and ethical issues that we need to think about," he said.

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