Future Solar Energy

As the threat global warming increases, the need to find efficient renewable energy sources intensifies. We have always known that fossil fuels will one day run out and when they do, an alternative is required. Nuclear was once marketed as a long term alternative to fossil fuels but it has its problem. A lot of investment is currently being put into wind turbines but we can’t guarantee when the wind will blow.

In 2007, Denmark received 20% of its electricity from wind power. That might sound impressive but all the wind power hasn’t replace any power stations. Denmark still has the same amount of power stations in operation. That is because the wind cannot be predicted. When it blows it generates lots of power but when it doesn’t blow no power is generated. Wind cannot be predicted which makes it a bad choice foe our power source.

The sun is very predictable. We know when it rises and we know when it sets. The sun bathes the earth with more energy each minute than the world consumes in one year. A photovoltaic cell is a device that can harness the suns energy and convert it to electricity. Scientists and corporations are working on new advanced solar cells that they hope will be the future solar energy.

Solar panels are not the only way to harvest the suns energy to make electrical power. It is also possible to concentrate the sun’s rays, use them to produce steam and drive a turbine. These two very different approaches illustrate an unresolved question about future solar energy: whether it will be generated centrally and transported over long distances to the consumer, as it has been in recent decades, or generated and consumed in more or less the same place, as it was a century ago.

The initial installation costs of solar panels are higher than some home owners are willing to pay. Engineers are working to change that and map the future of solar energy. One of them is Emanuel Sachs of MIT. Some engineers look for big, exciting technological improvements in the way solar cells work, but Dr Sachs prefers incremental change. As he sees it, it is such change that drives Moore’s law, that well-established description of the rapid improvement in the power of computer processors.

Solar power price/watt

Dr Sachs’s first contribution to future solar energy was a technique called the string ribbon, which halved the amount of silicon needed to make a solar cell by drawing the element (in liquid form) out of a vat between two strings. That invention was marketed by a firm called Evergreen Solar. Dr Sachs predicts that these innovations will bring the cost of solar cells below $2 a watt. That is close to cost of a coal-fired power station.

The diagram shows how the cost of solar electricity has reduced from nearly $20 a watt in 1980 to $4 a watt in 2006. The price is currently stable but as new innovation come onto the market, as demand increases, the cost will continue to fall. The future of solar energy is bright.