When the sun doesn’t shine on the beach it wrecks your tanning index. When the sun doesn’t shine on your solar panels you’re taking cold showers and eating soup out of the can – assuming you have a manual can opener.
The same goes for wind power. A wind turbine is a fine thing when the wind is blowing, but when the wind isn’t blowing the turbine is an overgrown, albino lawn flamingo.
Tidal power is not as flashy as solar and wind, but it’s insanely reliable. Tides come in and go back out without fail, no matter whether it’s cloudy or sunny, windy or calm. As they flow in and out, tides generate huge amounts of energy that can be converted into a predictable renewable energy stream.
By mid-March, up on the northeastern tip of the U.S., in Lubec, Maine, 
a company called Ocean Renewable Power Co. will begin operating the first grid-connected tidal power plant in the U.S. The 300-kilowatt (kW) tidal energy project consists of turbine generator units (TGUs) mounted on the sea floor. The 20-foot tide drives the turbines as it ebbs and flows. Check out what the Portland Press Herald wrote about the project. The coverage has a lot of good details.
Ocean Renewable’s Cobscook Bay Tidal Energy Project or is a fairly small pilot program that will produce enough electricity to supply 100-125 homes. The project’s larger purpose is to help determine the feasibility of larger-scale tidal power. The outlook is good, but what jumps out at students of renewable energy is what Ocean Renewable CEO Chris Sauer said about tidal power’s likely future.
“It’s never going to be the dominant power-generating resource in the state of Maine, but it’s going to be a significant contributor,” Sauer said.
That’s the kind of no-b.s. candor that the renewable energy industry is often missing. Too many rosy predictions about renewable energy’s prospects set unrealistic expectations. (Remember when “clean, safe” nuclear power was going to make electricity “too cheap to meter”? I do.)
Dissect Sauer’s observation and you find the likely shape of our energy future. Most of our energy won’t come from massive, centralized power plants like we have today because none of todays’ renewables have the energy density of fossil fuels. Instead, we’ll get electricity from a larger number of smaller renewable sources, each doing what they do best. Solar and wind will produce when the conditions are right. Tidal, biomass and players-to-be-named will fill in the gaps. And we’ll be consuming less because our homes, appliances and vehicles will be more efficient.