Starkraft opens prototype osmotic generator in Norway

[Terralthra]

The principle of harnessing osmosis has the potential to produce enormous amounts of energy anywhere that salt water and fresh water meet. We looked at some of the approaches to turning this theory into reality earlier this year, including Statkraft's plans to build a prototype power plant. The company's plans are now coming to fruition with Her Royal Highness Crown Princess Mette-Marit of Norway officially opening the world's first osmotic power plant prototype on November 24.

The osmotic power plant guides sea water and fresh water into separate chambers, which are divided by an artificial membrane. Salt molecules pull the fresh water through the membrane, increasing the pressure in the sea water chamber. This pressure is then utilized in a power generating turbine.

The prototype has a limited production capacity and will be used primarily for testing and data validation leading to the construction of a commercial power plant in a few years time. Statkraft claims that the technology has the global potential to generate clean, renewable energy equivalent to China's total electricity consumption in 2002 or half of the EU's total power production (some 1600 to 1700 Twh).

In theory, such power plants could be located wherever sea water and fresh water meet, such as the mouth of a river. They run without producing noise pollution or polluting emissions and can be integrated into existing industrial zones, perhaps being installed within unused areas of existing buildings.

A seminar on renewable energy was held as part of the opening ceremony where NASA's Michael Flynn said of the project: "Just like the globe we live on, a space station is a closed system, we are forced to recycle everything, in order to carry out space missions in an economically feasible manner. Water circulation is the link between Statkraft and NASA, but instead of using human waste Statkraft is using clean water to generate energy. NASA is interested in the membrane technology and will extend our full support to Statkraft on the road ahead."

Rasmus Hansson, head of WWF Norway, added: "In order to solve the climate challenge we need to redirect the production towards renewable energy sources as quickly as we can. Renewable energy investments must be made in developing countries, and osmosis is a good example of technology which could be used in developing nations. The climate crisis cannot be solved by market mechanisms, such as carbon-pricing alone, but the upside is that investments made in renewable and sustainable energy sources can become profitable very quickly."

The very first power generated by the prototype was used to boil a kettle to provide the guests with hot water for refreshments at the opening ceremony.

I don't know enough hydrodynamics to know whether or not StarKraft's claims are valid about the amount of energy they can extract. Any engineers want to weigh in?

[The Duchess of Zeon]

It depends. If you installed a huge subsurface installation for several trillion dollars across the mouth of the Amazon, you might well generate enough electrical power to wire all of South America. Certainly on the scale they're talking about it won't be "low Impact" like they claim.

[Mayabird]

Would it really work at the mouth of the Amazon? So much fresh water comes out that the ocean is fresh water for a good distance out and still less saline than usual a few hundred kilometers out.

[Starglider]

Would it really work at the mouth of the Amazon? So much fresh water comes out that the ocean is fresh water for a good distance out and still less saline than usual a few hundred kilometers out.

Presumably you could just pipe in seawater from an intake some way up the coast. Admittedly that would increase capital costs somewhat.

[Sea Skimmer]

If you are going to start building huge underwater piping and pumping systems, I’d strongly suspect that an ocean thermal energy conversion plant would produce more power for the cost then this idea. That technology is also much closer to being mature in general since plants using it have existed since the 1930s.

[The Duchess of Zeon]

Would it really work at the mouth of the Amazon? So much fresh water comes out that the ocean is fresh water for a good distance out and still less saline than usual a few hundred kilometers out.

Uhm, I was being slightly disparagingly facetious of the whole "low impact" part, so in my head there was this mental image of huge osmotic power generators built in a vast underwater facility across a sandbank somewhere in the mixing zone.

This is a very common fallacy of these kinds of schemes, though. They take figures for the absolute total amount of theoretical production from their method of energy generation worldwide, and then pretend this is actually achievable without multi-hundred-billion-dollar megaprojects.

[Starglider]

If you are going to start building huge underwater piping and pumping systems, I’d strongly suspect that an ocean thermal energy conversion plant would produce more power for the cost then this idea. That technology is also much closer to being mature in general since plants using it have existed since the 1930s.

I considered mentioning OTEC, but then it occurred to me that the attraction of this plant is the lack of off-shore infrastructure, which proved to be a bitch to maintain (even off-shore wind is having trouble and that's mechanically simpler). Sourcing saltwater for this wouldn't require offshore infrastructure; the pipeline can proceed up the coast (overland) until it's clear of the estuary area, with just a short feeder pipe extending from the pumping station. As for energy and cost efficiency, well, this seems to be one of those eco-projects where the main attraction is 'it's green!' and the economic justification is an afterthought.