You can count IBM as one more institution that sees at least some potential in the idea of harvesting power when fresh water and saltwater meet.
IBM's Almaden Laboratory wants to prepare a proposal to study osmotic pressure gradients, according to Spike Narayan, functional manager, science & technology, at IBM's Almaden Research Center.
Osmotic pressure gradients effectively generate water pressure without raging currents. They work like this. Fresh water from streams and rivers tumbles toward a tank of sea water. Between the fresh water and the sea sits a membrane. The differences in salt concentration draw the fresh water through the membrane. The membrane also can eliminate additional impurities.
As more fresh water enters the tank, the salt concentration decreases but the growing volume of water increases the water pressure in the tank. The pressure can then be harvested to turn a turbine. In effect, it is hydroelectric power without a Niagara.
The osmotic pressure project also illuminates how IBM exploits its fairly unique structure for profit. IBM is one of the few large companies with a sprawling R&D division with a somewhat open-ended mandate to look at projects that aren't necessarily tied to near and mid-term profits. IBM, moreover, isn't likely going to give up the prestige and Nobel prizes that go along with such a lab.
But, since bills do have to be paid, groups like Narayan's comb through different projects to identify commercially promising ideas. As the project progresses, IBM seeks out industrial partners and divisions with in its own consulting groups to commercialize and/or license it. Right now, one of the major green projects at IBM's labs involves components for lithium-air batteries.
Often, the path from lab to market is crooked. The potential for osmotic pressure power grows out of a material IBM has started to promote for desalination and water purification membranes. The material effectively forms a molecular net that fleeces impurities out of water and thereby cuts down the ostentatious amounts of energy required by most desalination systems. The material can also tune membranes to hone in on arsenic or boron or may one day allow governments to produce "recycled water" or purified water from sewage systems. Singapore already gets a small percentage of its drinking water (called NEWater) from recycling, although tourist brochures don't brag about it.
"The whole concept of recycled water is going to happen. It is inevitable," he said. "We need to figure out inexpensive ways to do it.
And where did that material originally come from? It is a polymer IBM originally devised to perfect immersion lithography, a technique for "drawing" the circuits in chips on wafers immersed in distilled water. Immersion lithography started being employed in mass production a few years ago. Thus, IBM's involvement in sea power derives from work Big Blue did on the PlayStation 3.
As wacky as osmotic pressure power sounds, interest is growing. Norway's Statkraft Energi is working with desalination expert Energy Recovery to prepare a pilot program to harvest osmotic power from the country's many fjords. (Don't let the Statkraft name fool you. This isn't a club you'd meet at a sci-fi convention: It's a large utility.)
Danish startup Aquaporin meanwhile is examining how it can deploy an artificial protein it has created for desalination for energy harvesting. Aquaporin works with French water giant Veolia on desalination research. You can get a more full description about osmotic pressure gradients from Rolf Aaberg from Norway's Statkraft Energi here.
"You have the potential of approximately 2,000 terawatt hours a year globally. Any place you have a stream going into the sea you have potential energy," Peter Holme Jensen, a microbiologist turned CEO of Aquaporin told us last year.
IBM will likely take a slightly different twist. Instead of creating osmotic pressure from introducing freshwater to seawater, IBM will see if it can generate osmotic pressure by introducing clean (or somewhat clean) water to the extremely salty waste streams at desalination plants. In effect, a natural stream wouldn't be necessary.
"You could generate more power" with concentrated seawater, Narayan said.