1-MW tidal turbine to be submerged this fall in Bay of Fundy
Nova Scotia Power has partnered up with Dublin, Ireland-based OpenHydro Group to install a 1-megawatt tidal turbine to the seabed in the Bay of Fundy. It’s OpenHydro’s first installation of its 1-MW machine and is expected to be fully operational later this fall. Over two years the two companies will collect operational data, including impacts on environment, robustness of equipment, and power generation. The sub-sea base was manufactured by a local company in Dartmouth, Nova Scotia.
The OpenHydro turbine is one of three being tested under a Nova Scotia government pilot program, which aims to tap the immense tidal-energy potential in the Bay of Fundy. The Electric Power Research Institute has identified the Bay as one of the best — if not the best — sites in North America to develop tidal-energy projects. In fact, it’s capable of realistically generating 300 megawatts of tital power. U.K.-based Marine Current and B.C.-based Clean Current are the other two turbine concepts slated for testing.
Tags: Clean Current, Marine Current, OpneHydro
Tyler Hamilton is editor-in-chief of Corporate Knights magazine and a business columnist for the Toronto Star, Canada's largest daily newspaper. In addition to this Clean Break blog, Tyler writes a weekly column of the same name that discusses trends, happenings and innovators in the clean technology and green energy market. This blog is a personal project started in April 2005. It is not an official blog of the newspaper.
September 23rd, 2009 at 1:24 pm
Won’t the capacity factor of these be fairly small? The only work when the tide is changing. On the other hand, tides are quite predictable.
September 24th, 2009 at 4:36 pm
@ StephenB:
When the tide is changing direction, there is actually very little current (at the precise moment of high tide or low tide, the tide is neither moving in nor out and is therefore still, hence it is called slack tide).
However, outside of the few minutes of slack tide, there is a very predictable tidal current, as you indicated. In fact, half of the total volume of water that must move in each change of the tides does so in only two hours (the two hours centred between a high and low tide – or low and high tide). This movement can produce significant currents, especially in narrow channels, and is therefore an important element of marine safety! These intense currents happen four times a day (providing a minimum of 8 hours of strong currents for tidal power generation!).
Given that the rate of flow is less near the high or low tide and much greater in the interval between high and low tides, the tidal current is not always strong enough to maximize the power output of a tidal turbine. The capacity factor is therefore a useful measurement. For those readers who might not be familiar with the term, capacity factor indicates what percentage of the maximum total power output is actually realized, based on the percentage of time the technology is engaged (e.g. the turbine is spinning) multiplied by its power output during that time (e.g. during low current speed, this turbine might output 0.5 MW instead of the rated 1 MW).
Preliminary numbers for tidal power indicate a capacity factor on the order of 22 to 25 %. This is more than solar (which is generally 15 to 20%) but less than wind (on the order of 27 to 32%). Although these capacity factor numbers all sound quite low, even coal only has a capacity factor of about 67%. Of all the available technologies, the most consistent and reliable (more than coal, nuclear, or natural gas) is geothermal, which has a capacity factor between 95 and 97%.
Each energy technology has its own pros and cons (many of which are complementary – wind and hydro, for example, offset each other’s lack of production quite well, both seasonally and on a diurnal cycle). Ultimately a blend of clean, renewable power sources will be ideal; where possible, geothermal can provide baseload, while technologies such as tidal, hydro, wind, wave, and solar contribute as available and appropriate.
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P.S. To Mr. Hamilton: I believe the Bay of Funday Tidal Power Pilot Project is a collaborative effort between the governments of Nova Scotia AND New Brunswick, yet N.B. is not mentioned here. Have I misunderstood?
September 24th, 2009 at 10:48 pm
The Bay of Fundy would be an almost unique spot for a tidal turbine- so much water gets funneled thru there that the tide rises and falls something like 50 feet a day. It could become the underwater equivalent of the Hoover Dam;-)
September 28th, 2009 at 1:59 pm
These things are just getting off on the learning curve, and already they appear quite affordable. After a GW or so has been built, they could be incredibly cheap on a levelised cost basis. Too bad the tidal energy resource isn’t huge compared to global consumption… But, it could be significant (on the order of hundreds of GW electrical).
There are a number of innovations going on for wind turbine blades and other equipment that could possibly be applied to tidal turbines in a similar fashion (the variable generators, advanced composite blades, the tubercle things, etc.)