Using solar energy to grow food appears to be an emerging micro-trend. A small, 4,000-square-foot demonstration project called Sundrop Farms, using the Australian outback's two most abundant resources - brackish water and sunlight - has been so successful that new investors and huge supermarket chains have been eager to sample this latest miracle in the desert: fresh produce - tomatoes, cucumbers and peppers - by the ton. The video on the right explains the process, which starts with an 80-yard line of parabolic mirrors that follow the sun and focus heat on a pipe containing oil. The hot oil then heats nearby tanks of seawater pumped up from a few feet below ground. The seawater turns into steam and drives turbines providing electricity. Some of the hot water also heats the greenhouse through the cold desert nights, while the rest is fed into a desalination plant that produces 2,500 gallons of fresh water a day for the thirsty plants. After just 18 months, the company's scientists and investors are about to start building an $11-million, 20-acre greenhouse - over 40 times bigger than the current one - which will produce 4 million pounds of tomatoes and 2 million pounds of peppers a year for supermarkets now competing for exclusive contracts.