Salt could shake up world energy supply
Thursday, 20 March 2008
TOFTE, Norway, March 19 (Reuters): Only up to powering light bulbs so far, "salt power" is a tantalising if distant prospect as high oil prices make alternative energy sources look more economical.
Two tiny projects to mix sea and river water-one by the fjord south of Oslo, the other at a Dutch seaside lake-are due on stream this year and may point to a new source of clean energy in estuaries from the Mississippi to the Yangtze.
The experiments, which seek to capture the energy released when fresh and salt water are mixed, build on knowledge that has been around for centuries-in one case imitating the process of osmosis used by trees to suck water from their roots.
Although they are far from being economically viable, if eventually successful they might help a long-term quest to diversify away from fossil fuels such as coal and oil, widely blamed for stoking global warming.
And rivers flow around the clock, an advantage compared to variable wind or solar power.
Oil, currently trading not far from a record $112 a barrel, is forecast to peak this year as a US slowdown reduces demand, but analysts polled by Reuters in February still saw the average price above $80 in 2010.
The UN Climate Panel said in 2007 energy sources such as waves, tidal power or salt are a long way off-unlikely to make a significant contribution to overall power needs by 2030.
The science at the heart of the projects is the fact that when salt and fresh water mix at river mouths, they are typically warmed by 0.1 degree Celsius (0.2 Fahrenheit). Dutch scientists say such energy at all the world's estuaries is equivalent to 20 per cent of world electricity demand.
The plants may support hopes the technology can overcome hurdles, the most significant of which is poor cost-effectiveness of the membranes used in the process.
In Norway, power group Statkraft, which says it is Europe's top producer of hydro and wind energy alongside Electricite de France, is building a test plant costing $20 million.
The plant, at Tofte on the Oslo fjord, will have output of up to about 5 kilowatts-enough to run household appliances such as washing machines or heaters or a few dozen lightbulbs.
Two tiny projects to mix sea and river water-one by the fjord south of Oslo, the other at a Dutch seaside lake-are due on stream this year and may point to a new source of clean energy in estuaries from the Mississippi to the Yangtze.
The experiments, which seek to capture the energy released when fresh and salt water are mixed, build on knowledge that has been around for centuries-in one case imitating the process of osmosis used by trees to suck water from their roots.
Although they are far from being economically viable, if eventually successful they might help a long-term quest to diversify away from fossil fuels such as coal and oil, widely blamed for stoking global warming.
And rivers flow around the clock, an advantage compared to variable wind or solar power.
Oil, currently trading not far from a record $112 a barrel, is forecast to peak this year as a US slowdown reduces demand, but analysts polled by Reuters in February still saw the average price above $80 in 2010.
The UN Climate Panel said in 2007 energy sources such as waves, tidal power or salt are a long way off-unlikely to make a significant contribution to overall power needs by 2030.
The science at the heart of the projects is the fact that when salt and fresh water mix at river mouths, they are typically warmed by 0.1 degree Celsius (0.2 Fahrenheit). Dutch scientists say such energy at all the world's estuaries is equivalent to 20 per cent of world electricity demand.
The plants may support hopes the technology can overcome hurdles, the most significant of which is poor cost-effectiveness of the membranes used in the process.
In Norway, power group Statkraft, which says it is Europe's top producer of hydro and wind energy alongside Electricite de France, is building a test plant costing $20 million.
The plant, at Tofte on the Oslo fjord, will have output of up to about 5 kilowatts-enough to run household appliances such as washing machines or heaters or a few dozen lightbulbs.