Tidal energy wades toward viability

Source: By Andrew Maykuth, Philadelphia Inquirer, Philadelphia Inquirer • Posted: Thursday, September 7, 2017

Engineers are fine-tuning what they hope is the next big development in renewable power: energy generated by tides flowing in and out.

High maintenance costs, environmental concerns and other obstacles have held back tidal power even as wind and solar power have become commercially competitive. Like other renewables, tidal energy is intermittent — ramping up every six hours and 25 minutes as the tides change — but the size and timing of its flows can be forecast years in advance, and the potential is enormous.

Near Nova Scotia, a 52-foot-diameter turbine weighing 1,100 tons has been brought back into port for upgrades after its latest trial. Strong tides in the Bay of Fundy have worn its paint and ripped away its metal anodes — but the turbine survived, which is an improvement over earlier models.

“This was the first machine that was able to generate power for that amount of time in that environment, so it was a resounding success,” said Christian Richard, director of Cape Sharp Tidal, a joint venture between Nova Scotia energy company Emera Inc. and the Irish turbine manufacturer OpenHydro.

The Cape Sharp Tidal model can generate 2 megawatts of electricity, similar to a large wind turbine.