We've all become used to seeing solar power in action. You can get pocket-sized panels to charge your mobile phone or you can get them many times larger to heat your hot water. As renewable technology develops, we can expect to see ever more interesting and useful products, but what's going on right now - and what can we hope to see in the near future?
Solar Panels - What Shape Would You Like?
Whether it's on the face of a watch or the roof of an industrial building, almost every solar panel you see is flat. It's mostly down to the manufacturing process. The most common type, polycrystalline (sometimes called multicrystalline), are made from multiple layers of silicon and, as a result, are inflexible. Even the more modern (and more efficient) monocrystalline type are still relatively fragile.
That's all started to change with the introduction of Thin Film (or amorphous) panels, where the silicon is sprayed onto a substrate as a vapour, so fine it's technically termed a gas! The resulting panels can be curved, giving much more flexibility in design. It sounds great, but it's not yet a complete solution. For one thing, Thin Film is currently less efficient than monocrystalline. Then there's the actual use of the solar device. It has to trap sunlight, so curving any part of it away from that light source inevitably reduces the output.
Though that disadvantage may never be completely overcome, an idea being developed at MIT could take the shaped panel just about anywhere people want it to go. Using Graphene, a carbon material, and Molybdenum Disulphide, they've managed to create a working solar cell just two atoms thick!
Its energy performance as it stands might seem poor - just 1 or 2% of a traditional panel - but it's less than a thousandth of the thickness. There's no reason why you shouldn't be able to stack one on top of another, so the potential applications would seem almost limitless.
So we know the technology continues to produce more and more useable power, but what about everyday applications?
It's now perfectly practical to have portable solar power that can run your laptop or light your campsite. It's even possible to cook your food. Basic 'sun ovens' are nothing more than cardboard covered with foil - you could probably make one yourself - but commercial versions are available that can take temperatures to well over 300° Fahrenheit. Put your food in a black cooking pot with a lid, pop it in the oven and you can have hot food wherever you go.
Ever used a magnifying glass to burn paper or wood? Imagine taking that concept and using it to forge metal. That's exactly what Green Power Science has done in Tampa, Florida. With little more than a big Fresnel lens on a wooden frame, they've reached temperatures of 3800°F. OK, not the most practical idea ever, but it shows the extremes that solar power can be taken to.
More useable perhaps is the solar scooter. Modelled on the child's toy (rather than the vehicle made popular by Mods), the entire platform you stand on is made from photovoltaic cells. The resulting scooter might only do 15 mph, but that's pretty nippy when compared to the average cyclist, and with a range of 20 miles between charges it could be a very convenient way to get around town.
After heating our water and powering our homes, getting us around is arguably the biggest market for any device. So where are we on solar transport?
Currently, it's batteries that power the majority of renewable energy vehicles - not normally fed by sunlight but by more traditional means. However, there are several solar cars around and, though a little weird and wonderful for you to see on local roads any time soon, they are at least at the stage when more than one person can get in them. Indeed the STE project from Eindhoven, in the Netherlands, has developed the world's first family-sized vehicle, with room for four adults and even a boot. It will do around 600 miles on a single charge and the top speed is 110 kph. Not fast, but it shows how quickly technology is progressing.
The ultimate proof of that has to be the Solar Impulse, a solar-powered plane that recently flew coast-to-coast across the United States. It may have taken 105 hours and 41 minutes, but it's still a remarkable achievement. In case you think it's another demonstration of renewable energy that doesn't really have practical applications, you might want to look at aviation history. The Wright Brothers first flew in 1903, yet less than 25 years later international commercial flights were commonplace. Makes you wonder, doesn't it.