Getting Power From Salty Water (Osmosis)

[OKIsItJustMe]

http://www.forbes.com/technology/2008/06/18/european-energy-innovations-tech-innovationeu08-cx_vr_0618energy.html

Europe Innovates

Getting Power From Salty Water

Vidya Ram , 06.18.08, 6:00 PM ET

LONDON, U.K. -

In the quest to tap new sources of renewable energy, scientists are turning to the sun, to the wind, and of course, to a variety of bio-derived fuel alternatives. But in Norway, one company is also turning to salty water.

The concept of osmosis may mostly dredge up memories of high school biology. It is the process of moving water from an area with a low concentration of dissolved material, such as salt, to a place with a high concentration, by passing through a membrane.

Now scientists at Norwegian renewable-energy company Statkraft aim to use osmosis to generate electric power. It's a tantalizing prospect: Based on an estimate of the number of rivers around the world with suitable conditions, it's a potential source of 1,700 terawatt hours a year of energy globally, according to estimates by Statkraft's scientists. That's equivalent to the electricity consumption for all of China in 2002.

In June, Statkraft began building the world's first osmotic power plant, and hopes to have it up and running by the end of the year. Its a 100-square-meter plant, based in a paper-pulp factory near Oslo Fjord and is expected to generate up to four kilowatts of power. If all goes according to plan, Statkraft hopes to have a full-scale plant operational, generating up to 100 megawatts a year within seven years' time.

...

[MannyGoldstein]

1. What's A "Megawatt Per Year"

"Watt" is an instantaneous measure.

[phantom power]

2. Welcome to the Purgatory of Bad Science/Technology Reporting.

[MannyGoldstein]

4. The Summer Solstice Is When The Earth Is Closest To The Sun

Or so the Boston Globe wrote a few years ago. I gave them a heads up but they never issued a correction.

Oy.

[OKIsItJustMe]

3. I'm guessing that should be "megawatt hour" per year...

(Based on the fact that they used "1,700 terawatt hours a year" earlier in the article.)

Of course, they might mean a "megawatt year"... ;-)

[kristopher]

7. I think you're correct.

It's a 4 kW plant, which means full capacity is about 35 MWh/year. The article states they hope to expand and "reach" the questionable figure in 7 years. That means a tripling of capacity.

[NYC_SKP]

5. 100-square-meter plant???

What, a power plant measuring only 32.8 feet on each side? That's smaller than my very small house. Maybe they meant "100-meter-square", which would still be on the small side.

I don't know, coupled with the very silly "100 megawatts a year" statistic, I have to question the veracity of the entire article, though I embrace the concept.

To anyone who knows more about this technology:
Am I to believe from this passage that fresh water is consumed in the process?:

Leveraging the power of osmosis to generate electricity is a concept that has been discussed since the 1970s. The theory is relatively simple: Seawater and freshwater, filtered to remove silt, are fed into pipes which lead to a membrane system, made up of spiral coils to maximize surface area. The salt of the seawater draws the fresh water across the membrane, leading to a build-up of pressure which forces water through the turbine, generating electricity.

[Dead_Parrot]

6. Dumb-reporter-less info here:

http://www.statkraft.no/Images/Statkraft%20Osmotic%20Power%20Update%20SCREEN_tcm3-8318.pdf (PDF)

Undecided myself, but it looks plausible.