Solar-powered devices come with a slew of technological hurdles – the power conversion efficiencies of solar panels have improved only incrementally, while the materials for even the most efficient devices remain costly – but engineers and scientists continue to work diligently toward harnessing one of the earth’s most abundant renewable energy resources.
One problem, however, still casts a shadow on the dawn of a new energy era, one that not even the most sophisticated technologies of the future can change (well, the near future anyway): it’s not always sunny.
But it is possible to provide solar power in the absence of sunlight, as two companies demonstrated last month when they announced separately two kinds of solar-powered chargers.
The MacGuffin 