Franz Alt and the seawater desalinationReally on a web site named ''solar page.com'', Franz Alt criticiseed June 24 2007 the energy consumption of sea water desalination.
In the article are expressions like "big energy usage", "The method requires much electric power". But how much electric power? About this gives the Franz Alt article no answer, the taks is to make a mood, not to inform the readers.
Modern sea water desalination systems require 2,5 kWh per cubicmeter seawater. For the distribution of the water, let's assume 0,5 kWh per m³ for pumps. My household with 5 persons needs now about 200m³ water per year. Let's be generouse and take 100 m³ more for the garden. 300m³ seewater desalination and distribution neede 900 kWh. In the hot dry regions where seawater desalination is required, a photovoltaic can be calculated with 1500 Wh yearly yield per Watt peak installed. So only 600 Watt photovoltaic on the roof are enough, at current photovoltaic modules only 4m² roof.
Beside photovoltaic is also wind power. The largest wind power plants have 5 MW and produce in a windy area enough electric power for 3 million m³ water per year. At 75m³ yearly usage per human enough to supply 40.000 humans with water. |
