Voltaic recently brought out the Spark Tablet Case, a solar-charging streamlined case that can generate 8 watts for your iPad or other tablet. It takes about 10 hours in direct sun to fully charge and the panels are waterproof, lightweight and durable.
Another neat alternative method of charging is ‘piezoelectricity’ — the charge which accumulates in certain solid materials in response to mechanical stress or pressure. Researchers in Australia have carried out a study that looks into harnessing the energy we generate while typing, and using it to power a laptop. A thin film of piezoelectric material developed using nanotechnology would coat the electronic parts and the energy from pushing down the keys could be used instead of battery power.