New technology means solar power could one day provide all the world's energy needs – but governments must do their bit.
Until a few years ago the suggestion that solar power might provide the answer to the intertwined problems of long term energy security and climate change would have been dismissed as a pipedream. The high cost of solar cells, their inefficiency in converting the sun's rays into electricity and the lack of state investment or assistance for renewable energy start-ups meant there was little hope.
But now, thanks to some determined innovators, the rising cost of fossil fuels and the widespread realization about the damage they cause and some clever market regulation, a solar transition is rapidly become a reality.
In Germany, solar energy already provides 3 gigawatts of electricity, the equivalent of four large fossil fuel power stations. In 2003, the German government passed a law obliging energy companies to purchase solar energy from anyone who can produce it at nearly double the market price. The result? Homeowners and business flocked to buy photo voltaic (PV) cells and Germany's 300,000 PV cells now account for nearly 60% of the world's solar panels. This upsurge for demand for in solar technology has had the knock-on effect of stimulating research and development.
It is this technological development that is really exciting environmentalists. At the beginning of the decade PV cells rarely converted more than 5% of the sunlight they captured into electricity. Last year, researchers at the University of Delaware set a record with over 40% efficiency using new manufacturing techniques. While it obviously takes time for these developments to come to market, many commercially available PV cells now operate at around 20% efficiency. As a result of these increases in efficiency, the retail price of solar-generated electricity is rapidly approaching the prices of nuclear and gas-generated electricity in many parts of the world.
While many of those rushing to join the party are happy to simply continue developing existing silicon-based technologies, scientists at the University of California have other ideas. Building on the invention of conductive plastics (for which Alan McDiarmid, Hideki Shirakawa and Allen Heeger won the Nobel Prize for Chemistry in 2000) the researchers hope to use soluble materials to manufacture PV cells using an incredibly cheap printing-type process. While they are unlikely to achieve efficiency above the 10% mark in the next couple of years the vastly less expensive manufacturing processes involved mean that commercially competitive solar energy could emerge a lot quicker than previously imagined.
So, now that it is clear that at some point in the not too distant future solar energy will become commercially competitive, how far can the technology be taken? A New Scientist article on the subject estimated that the global economy's total energy demand stands at 15 terrawatts. Working on the assumption that PV cells reach a commercially viable efficiency of around 20% the article estimated that an area of just 300,000km2 would be needed to meet the entire planet's electricity demand. It sounds like a lot, but it fact it’s an area not much bigger than the UK. There seems little reason why one day huge areas of Saudi Arabian, Australian or Saharan desert couldn't be filled with massive solar power plants.
So why won't it happen tomorrow? Well for a start, whilst a few western European nations are implementing the German model, most western governments are simply failing to support fledgling renewable energy companies. For example, last year the UK government decided to plough millions into extending the life of its nuclear and fossil infrastructure and provided limited help for energy startups, let alone potential consumers of renewable energy.
There are also still a plethora of technical issues to overcome. Firstly, new research has shown that the small windmills and solar panels that are fitted to our rooftops often create more greenhouse emissions during manufacture than their use curtails. Secondly, how do we store the energy solar power creates for a rainy day? Hydrogen is notoriously dangerous to transport and there are huge inefficiencies when you start converting and moving energy about.
But the facts remain that whilst our politicians celebrate the idea that at some point in the future we might set binding green house gas targets, true alternatives to fossil fuels are starting to become a reality.