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.
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.