Photovoltaic electricity generation without sunlight

MIT researchers have developed a new photovoltaic energy-conversion system which can be powered solely by heat, generating electricity with no sunlight needed.

The researchers found a novel way of engineering the surface of a material to convert heat into precisely tuned wavelengths of light. This light is adjusted to match the wavelengths that photovoltaic cells can best convert to electricity, boosting conversion efficiency.

The key is a material with billions of nanoscale pits etched on its surface. When the material absorbs heat from any source, the pitted surface radiates energy primarily at chosen wavelengths.

According to the researchers, they have used the technology to make a button-sized power generator fuelled by butane that can run three times longer than a lithium-ion battery of the same weight.

Recharging the device is as simple as snapping in a tiny cartridge of fresh fuel. Another device, powered by a radioisotope that steadily produces heat from radioactive decay, could generate electricity for 30 years without refuelling or servicing.

The main advantage with the development is the ability to convert heat from various sources into electricity without moving parts, in a relatively inexpensive, small scale and efficient manner.