A team of engineers has devised an incredible plan to combine sea water, food cultivation with solar power to create enormous amounts of food, energy and much needed clean water in deserts. The Sahara Forest Project, which is already running demonstration plants in Tenerife, Oman and the United Arab Emirates, envisages huge greenhouses with concentrated solar power (CSP), a technology that uses mirrors to focus the sun's rays, creating steam to drive turbines to generate electricity.
The massive project would turn deserts into lush patches of vegetation, according to its designers, and do away with the need to dig wells for fresh water, an activity that has depleted aquifers across the world.
Charlie Paton, a member of the team, and the inventor of the Seawater Greenhouse, said the scheme was a proven way to transform arid environments. "Plants need light for growth but they don't like heat beyond a certain point," he said.
Above certain temperatures the amount of water lost through leaves' stomata rises so much plants stop their photosynthesis and do not grow. The solar farm planned by the project runs seawater evaporators, pumping damp, cool air through the greenhouses. This reduces the warmth inside by about 15C, compared with the temperature outside.
The system is quite remarkable since some of the greenhouse water vapor is used to water the crops and a portion is also used to clean the solar mirrors.
"So we've got conditions in the greenhouse of high humidity and lower temperature," said Paton. "The crops sitting in this slightly steamy, humid condition can grow fantastically well."
The designers said that most any vegetables could be grown in the greenhouses. The pilot plants already have produced a variety of vegetables including lettuces, peppers, cucumbers and tomatoes. The nutrients to grow the plants could come from local seaweed or be extracted from the seawater.
The cost of the Sahara Forest Project could be relatively low as both CSP and Seawater Greenhouses are proven technologies. The designers estimate that building nearly 50 acres of greenhouses combined with a 10MW CSP scheme would cost about $120m.