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Growing Eastern economies are demanding yet more power, so alternatives to fossil based energy have never been more urgently needed. Giles Crosse discovers innovative Norwegian research that just might provide an answer.
Whether it’s tidal, wave, wind or solar power, the race is on to find reliable, effective renewable energy. It’s among the most pressing challenges facing us. Unprecedented power needs from hitherto third world economies, plus a growing scarcity of fossil fuels threatens global stability and production. This shortfall ultimately risks worldwide conflict and starvation. Resources: Osmotic Power, The Pro Concept
Cells for the future
So what’s the answer? It could be a new energy form mimicking human cell interaction, just prototyped in Norway. Stein Erik Skilhagen, Vice President for Osmotic Power at Statkraft, explains more:
“When fresh river water meets seawater, there is a difference in salinity. Energy is released when nature attempts to equalise this difference, there’s a small temperature rise.”
“We change this heat into electrical energy. Salt in seawater draws fresh water through a membrane, causing a pressure rise, which drives a turbine. The process just mimics what nature has always done in cells in your body, mine and in plants.”
Of course, it’s not enough to just demonstrate this in the lab: meaningful developments have to work out there in the real world. “Our initial results in the late 90’s were tough, poor efficiency.” continues Skilhagen.
“So we’ve redesigned the systems to work at a lower pressure, the fresh water can flow by itself, and we use thinner membranes. We’re producing 3 watts per square metre of membrane in the lab. We need to get to 5 watts per square metre for commercial viability, so we’re nearly there.”
Reliable resources?
“The really exciting thing is river water is predictive, so this resource is reliable seven days a week.” Skilhagen continues. It’s a vital point. Other renewables change given cloudy days or adverse weather conditions:
“Tide, wind, solar, they all vary. Plus people always live by the sea, there are communities, factories, industry by the sea.” Many of the world’s biggest cities are ports too. “So you build local stations and then there’s no need to transport the energy, or build pylons, pipes or infrastructure.”
Vexingly, the technology will only work in countries bordering the sea. And highly polluted rivers or industrial effluents might damage the sensitive membranes. These concerns illustrate a key point to sustainable energy sourcing: selecting solutions that match up well with local scenarios.
“Our country has lots of waterfalls, hydropower makes the most of this and osmotic aims to exploit such energy in the same way. This type of energy suits us and it’s similar to our existing business as the largest producer of this kind of energy in Europe.” says Skilhagen.
Inspiring investment
But what true potential for change does this technology offer? Skilhagen reckons a certain scale of installation is needed for it all to work effectively, and he believes if this can be achieved there’s scope for a genuine contribution to world power needs.
“We aim to produce 10 kilowatts using 2000 square metres of membrane. For the time being we’ll probably only get between 2 and 4 kilowatts, but there’s more work to be done.”
“On the basis of a dry season, we think we can achieve 1600 to 1700 terrawatt hours with facilities worldwide, which is substantial.” he continues. Statkraft statistics suggest that’s equal to China’s energy consumption back in 2002. “We could provide 10 per cent of Norway’s total power needs.” Skilhagen confirms. “So you can see this could really shake things up.”
Yet all too often, success or failure for innovative science depends on government investment. Independent multinationals, tied up in shareholder demands for ever increasing profit, can be unwilling to take a punt on expensive, commercially untried technologies.
Intriguingly, from 22 September, the UK government is offering £22 million to marine renewables developers to speed the uptake of these forms of microgeneration. This kind of investment is really needed on a worldwide scale, to build potential for sustainable energy.
Then again, certain estimates suggest recent bank bailouts alone could cost the UK £175 billion. Against this background, it’s existing investment towards renewables seems little more than a drop in the ocean.
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