The first commercial tidal energy generation project in the United States went online on this week in the waters off Lubec, Maine. The project by Portland, Maine-based Ocean Renewable Power Co. will eventually produce enough electricity with its 20 underwater turbines to power 1,200 homes. Maine and Alaska are the only two U.S. states with tides strong enough for commercial energy production.
I am a little confused by the post and the newspaper article. The newspaper article says that 180 kW is enough to power 30 homes. That’s 6 kW per home. Let’s forget about the fact that home energy consumption is measured in kW-hours, not kW.
The post says that eventually 20 turbines will power 1200 homes. At 6 kW per home, 7200 kW would be needed. But at 180 kW per turbine, 20 would produce 3600 kW, half of what is needed. Is there something wrong with my math?
What troubles me more, is that I think that the 180 kW is the maximum power, and not the average over some period – say 24 hours. As far as I know, wind turbines produce about 25% to 30% of the nameplate or rated power. Tidal flow can be predicted, but it’s not always maximum over several tides.
So the most relevant quantity is the energy in kW-hours produced over a time period which includes several tides. Since energy is now being delivered to the grid, this quantity should be easy to determine.