With potable water becoming an increasingly scarce resource in some countries, governments are turning to solutions such as desalination. An energy-intensive process, desalination has been made “greener” through the use of renewable energy.
Reverse osmosis is the most economical form of desalination, but still requires in excess of 3 kWh per cubic meter of water. Wind turbines and solar panels can be used to help supply this power, but a new method turns wind energy straight into water pressure for use in reverse osmosis systems – without converting it first to electrical power.
Using a wind energy harvesting device that looks more like the windmills commonly seen in rural areas of Australia, U.S. based Engineering For The Earth‘s Aeolus system require minimal wind speeds and can produce drinking water for communities of up to 500 people per unit. The only additional energy input required is for telemetry, which can be supplied via small solar panels.
The windmill produces mechanical power to drive a pump that takes water from the source. The pressure drives the water through a series of filters including the reverse osmosis membrane and the purified water is then stored, ready for use. The company says bypassing electrical power has other significant advantages, including improved robustness, better reliability, and lower cost.
The company is developing fixed units with fans ranging from 2.4m to 6 and a transportable unit with a 3.6m fan. The smaller fans can purify and desalinate brackish water; with the larger models capable of desalinating and purifying seawater.