Marine energy has long looked to be a niche area, capable of meeting just a few percent of global power demand. But this seemingly limited energy source is drawing some big players, the latest being Siemens. The German engineering giant boosted its stake this month in Bristol, U.K.-based tidal energy developer Marine Current Turbines from under 10 percent to 45 percent. The attraction, according to Michael Axmann, chief financial officer for Siemens’s solar and hydro division, is the predictability of marine power.
Solar and wind farm operators struggle to predict tomorrow’s output, and bad forecasts can wreak havoc with power transmission planning and market prices. In contrast, the gravitational pull of the moon and sun that controls tidal cycles provides a sure means of anticipating the output from tidal generating stations. “Power output of the systems could be calculated for centuries in advance,” says Axmann.
The result could be higher revenues. Axmann notes that tidal power is “not subject to volatility. This increases the value of the energy produced, and hence makes the business case more reliable for the investor and operator.”
Axmann declined to say how much value would be added by that predictability. But he anticipates that, by 2020, marine turbines will deliver power at a cost that’s competitive with today’s offshore wind farms—in spite of the challenges involved in engineering for underwater operations.
Marine Current Turbines CEO Andrew Tyler says a combination of cost reductions and government incentives will ensure the profitability of his firm’s tidal power parks. He expects a return on investment for the company’s first two offshore power parks: a proposed four-turbine array off Scotland’s Isle of Skye and a five-turbine array off the northwest coast of Wales.
Cost reductions will come in part from scaling up its dual-rotor units to two megawatts from the 1.2 megawatts generated by its demonstration turbine, which has been producing power in Northern Ireland’s Strangford Lough since 2008. Future cost reductions, Tyler says, will come primarily from efficiency in equipment assembly and logistics, drawing on Siemens’s expertise in these areas.