Everyone knows what the biggest problem with solar power is: unreliability. On some days, the sun shines forth in all its glory, and on others, we can hardly see it at all. And even if one lives in a sunny spot, we can harvest the sun’s rays only during the daytime. What if it was possible to enjoy the sun’s power round the clock? It’s possible, says Terry Murphy, president of SolarReserve. His company has built a plant which absorbs the sun’s energy and transmits it out, twenty four hours a day. How do they do it? They use the sun’s heat to turn turbines with liquid, but unlike conventional plants, they focus solar energy using a huge arrangement of mirrors into a container of salt! A special salt melts at a high temperature into a liquid that is twice as dense as water. And what’s more, the salt can retain enormous quantities of heat for hours when stored in thermal silos, ensuring energy production, anytime you want it! Pretty neat, huh?