Blue Energy – Salt Water, Fresh Water, and Electricity
Filed Under: Green Technology on November 29, 2009
The idea that when you mix salt water with fresh water, a charge difference allows you to siphon off the extra electrons for power generation has been around for a century. The theory is often attributed to Nikola Tesla, though the actual practice wasn’t tested in a laboratory until the 1950s.
The most common method for doing this efficiently is called reverse electrodialysis. Basically, you mix the two waters together in a controlled fashion over a fusion membrane, which collects the power generated. Think of it as reverse osmosis on steroids.
At the Wageningen University and Research Centre, a doctoral student named Jan Post has presented his research into reverse electrodialysis. He hopes to take his plans to large-scale testing where the Rhine (freshwater source) and the ocean meet in the Netherlands, near Rotterdam.
His hope is to tie in the experimental facility with the reconstruction plans for the Afsluitdijk dikes in the area to facilitate both an easier construction for the mixing process as well as to combine costs.
Post’s figures estimate that the technical potential at this point in the river would be 2.4 gigawatts per year and the practical would likely be around 1.5gW. That would satisfy about 4 million households. He wants to start with a 200 megawatt facility for his trials.
If he is successful and his trials work out, then in ten to fifteen years’ time, a small series of facilities capable of several hundred megawatts each could supply 1.5gW of power or more.
Very cool indeed.
