Osmotic power plant opens, with commercial scale ambitions

The world’s first osmotic power plant opened today at Tofte, outside of Oslo. And it included a royal kickoff from the Crown Princess Mette-Marit of Norway, who pushed the button that set the turbines in motion.

The plant has been developed over the past year by Norwegian state-owned electricity company Statkraft, its Head of Osmotic Power Stein Erik Skilhagan told the Cleantech Group today. It generates power from energy retrieved from the difference in the salt concentration between seawater and river water.

Skilhagan said today marks a milestone on the path to realizing “a new source of renewable energy.”

Environmental experts and those in attendance, including Norway’s Minister of Oil and Energy Terje Riis-Johansen, toured the facility and held a series of discussions about the plant’s potential and how it could be improved.

With the technology, saltwater and freshwater are funneled into separate chambers, divided by an artificial semi-permeable membrane, according to Statkraft. The salt molecules in the seawater pull the freshwater through the membrane, increasing pressure on the seawater side.

The pressure comes in the form of a 120-meter water column or waterfall that can be utilized in a power generating turbine (see Osmotic power plant to receive royal debut in Norway).

In theory, osmotic power plants can be located wherever rivers meet the sea, and with Norway's fjords there are plenty of possibilities. The plants are quiet and can be integrated into existing industrial zones, such as the basements of industrial buildings, the company said.

The prototype, which has been developed in cooperation with research and development organizations from various countries, is to be used for testing and development. Statkraft eventually expects to construct a commercial scale plant, Skilhagan said.

The concept of osmotic power has long been understood, but is only now reaching viability. In the past, it has consumed too much energy for the process to be feasible at larger volumes.

However, the energy consumption at the Tofte site is being reduced because of technology from San Leandro, Calif.-based Energy Recovery (Nasdaq:ERII), Skilhagan said.

Energy Recovery’s Pressure Exchanger energy recovery devices aim to reduce the energy costs of the osmotic power process by up to 60 percent, Statkraft said.

The Pressure Exchanger technology is currently being used in seawater reverse osmosis desalination systems worldwide, where Energy Recovery says it is helping to bring down costs (see Energy Recovery launches new desal tech at IDA World Congress and Energy Recovery tech slated for new Australian desal plant). 

Energy Recovery’s Chief Technology Officer Rick Stover said two of its PX-240 units, which are suitable for the brackish water market, have been deployed at the Tofte site and were essentially donated.

"Without the PX device, the osmotic power process does not work, meaning you consume more energy than you produce, with the way Statkraft has configured it with seawater and river water," Stover said.

Similar to Energy Recovery's PX-300 units, the PX-240 is made to perform with high efficiencies at low pressures. The company hasn't sold many PX-240s, but is close to closing a couple deals in the United States, Stover said.  

Statkraft said the global potential of osmotic power is estimated at 1,600-1,700 terrawatt hours per year, or the same as 50 percent of the European Union’s total power production.

"It's really ideal cleantech," Stover said. "And it's because the plant operations will produce no carbon, and it's a renewable energy source. But what's even better is that unlike wind, solar, or wave power even, it's a continuous source of energy. It can supply baseload."

Skilhagan said the new prototype is designed to produce 10 kilowatts, but is currently producing only about 2 kilowatts.

“Today, we have shot the starting gun,” he said. “We need to show significant improvement and scale up in the next few years.”

Statkraft has ambitious plans for a scaled up version of its technology, at 25 megawatts by 2015. This could include hundreds of Energy Recovery devices, although Stover said his company isn't counting its chickens before they hatch because the membrane aspect of the technology is outside of his company's control. 

It's also not going to happen without participation from various stakeholders, including industry suppliers, utilities, and government entities, Skilhagan said. He said system suppliers and those in the membrane industry have the potential to benefit.

“We need stronger movement from them than we have seen so far,” he said.

He also said the plant’s current membrane technology is producing 60 percent of Statkraft’s target volumes. The company is working on how to generate the same or better results with larger manufacturing volumes.

There have been several utilities eager to participate and learn from Statkraft, from the United States, Europe, and elsewhere in the world, he said, without disclosing which ones.

He also suggested that government agencies need to treat osmotic power like other marine technologies and back it accordingly. The governments of Norway and the EU have contributed about $10 million to the project to date, with another $20 million coming from Statkraft, which includes research of osmotic power. The plant itself cost about $7 million to $8 million.

Statkraft also develops and generates hydropower, wind power, marine energy, solar power, and other energy solutions (see Statkraft, SCA to build 2.8TWh of wind and Statkraft takes stake in Arise Windpower). Statkraft had €3.1 billion ($4.5 billion) in gross operating revenue for 2008.