Good question. There is a huge amount of innovation happening everywhere in renewable energy and although solar technology has evolved rapidly in the last few years there is still a long way to go. There are lots of different aspects of a photovoltaic system that can be improved, and I will cover as many of them as I can on these pages.

First of all though, what is the basis on which we can judge these improvements? What is the ultimate goal here? Everyone can have their own opinion, but my ambition is to see solar energy compete economically with conventional energy sources, and for that to happen requires just one thing, lower cost of energy. Now you can get to lower cost of energy either by reducing the cost of the solar energy system or by increasing the amount of energy you get out of it. As we shall see, people everywhere are coming up with a lot of cool technology to go down both of these routes, but lets start with a company that I like called Nanosolar, who may eventually make the key step that makes solar power cheaper than coal.

First a bit of background: Solar panels are the most expensive part of a Solar electricity system, making up between half to two thirds of all the upfront costs. Most solar panels (sometimes called photovoltaic panels) are made from 50 or so ‘solar cells’ which are thin slices of silicon crystals specially treated so that they can turn sunlight into electricity. Its basically the same process that’s used to make electronic chips, which is fine for making tiny things that go inside your computer, but quite expensive for covering a small fraction of the earth’s surface with. Therefore a phenomenal amount of research has and is being done to find cheaper alternatives. So far the leading candidate for a replacement is the called ‘thin-film’ solar cell. In this case you start with flat panel of material such as glass, and coat the whole thing in a series of super-thin electronic layers that convert the sunlight into electricity. This process is cheaper than making normal silicon panels, however they are not as efficient at producing electricity.

Nanosolar are a frontrunner in developing thin film solar panels and are taking the technology to the next level. Most makers of thin-film solar panels need to use big vacuum chambers to deposit the semiconductor and can only process one panel at a time. Not so Nanosolar; they’ve cleverly developed a special electronic ink that they can literally ‘print’ onto big rolls of flexible metal sheets. Their factory in Silicon Valley looks very similar to a newspaper printing press – it’s much more suited to covering large areas.

When running at full speed the printing press should be able to cover XX football fields a day. Once the electronic layers have been printed on the foil they are cut into 6-inch squares and flown to another, newly opened factory in Germany where they are laid out into modules sandwiched in glass. Nanosolar claim their process is much cheaper than existing manufacturers out there, so cheap that it doesn’t matter that their panels are less efficient than traditional silicon solar panels. If this is really true be good news for consumers in the future, as Nanosolar could significantly bring down the price of solar panels.

Its not all plain-sailing for the US company however. They’ve been working on their process for nearly ten years and so far spent around half a billion dollars and have very little in the way of earnings. They’ll have to sell a lot of solar panels before their investors can start to relax. As with all new technologies, it takes time for customers to overcome reliability concerns, so getting to high sales volumes may take a bit of time.

Whether it’s Nanosolar that succeeds or one of the few dozen other firms pursuing similar strategies is not so important. What is important is that technology makes solar power economically viable without subsidies, and as we shall discuss on this blog, there are a lot of people out there dedicated to making that happen.