In a 'green chemistry' discovery scientists have taken a molecule of carbon, hydrogen & nitrogen, exposed it to sunlight & then stored the energy-rich isomer as a liquid & film. Returning the isomer to its original state releases heat, link that to a thermoelectric generator and you also get electricity. This creates a zero-emission, long-term solar energy storage system(18years!), which uses benign, all-renewable materials. Not yet delivering large-scale energy, nor cost-effective, but it is MOST promising! Pun intended - as the energy storage process is known as - Molecular Solar Thermal (MOST).