Monday, October 02, 2006

Wind Powerless

An article in today's Daily Yomiuri about a single large wind turbine in Gunma-ken is very frustrating. The headline says "Wind-power station generates losses", and goes on to talk about the money they've lost, but with such an odd collection of numbers that it's hard to figure out exactly what's what.

"The facility was projected to produce 327,200 kilowatts of electricity a year," the article says. Yup, that's what it says. Not "kilowatt-hours", "kilowatts". If we assume that they meant to say kilowatt-hours, that's a year-round average production of 37.352 kilowatts. That seems modest for such a large turbine (there's a photo, it must be at least eight or ten stories high, but it's hard to tell), but the article doesn't give its size or peak output rating. Worse, the turbine generated only 274,000 "kilowatts" in its best year, fiscal 2000, and last year generated only 192,000, less than sixty percent of the planned output.

The article also gives some economic figures -- saying that the Gunma government spent 76 million yen (about three quarters of a million dollars) and the New Energy and Industrial Energy Development Organization (NEDO) kicking in 57 million yen -- but it doesn't say what those costs covered. The losses are listed at five to seven and a half million yen (forty-five to sixty-grand, give or take) a year, but it doesn't say what price was being paid per kWh, what subsidies were in place, what the operating costs are, etc. Wind power in general still requires some subsidies to be economically competitive (until the price of coal and oil go up; it may already be competitive with nuclear, once government supports are factored in). Are the losses after those? Or do they not exist here? I'm not sure.

The article also talks about the "optimum wind velocity for power generation" being 13.5 meters/second. Of course, there is no such thing as a blanket statement; the power generated continues to rise as the wind speed goes up, until the turbine itself begins to be threatened by the winds. Certainly a wind that slow wouldn't be a problem. The article does say that average speeds at the facility have been no more than 3.6 m/sec. (and the power rises with the square of the wind speed, too).

"Its disappointing performance is blamed on a miscalculation of the winds expected in the area," it says. Uh-huh. Nobody knew that at Yoshiokamachi, between Mt. Haruna and the Tonegawa River, there wouldn't be enough wind. I'll bet a little digging would turn up interesting things in the site selection process. The article does seem to say that feasibility studies at Tsumakoimura, Showamura and Harunamachi showed negative results.

Ah, I did find a couple of sites (in Japanese) with some info on the project. It's a 300kw peak output turbine, built by Mitsubishi, and the blades automatically feather in winds above 24m/sec. I don't see at what speed the 300kw is output. One of the articles says this is enough power for 90 regular homes.

This one isn't it, but coming home on the shinkansen the other day, we saw a similar turbine deep in a valley somewhere in Fukushima-ken. It struck us as unlikely that such a location has strong enough winds regularly to make wind power attractive. I've also seen several near the port in Naoetsu, I believe, where it seems to make more sense. Japan as a whole is gradually catching on to wind power, and it's not uncommon to see new houses with small solar arrays on top, too. Maybe there's hope yet.

3 Comments:

At 9:31 AM, Blogger Tom Gray said...

Thanks for the detective work!

My amateur opinion: 327,000 kWh (as you point out, not kW) seems like an extremely low output figure for a 300-kW machine, amounting to a capacity factor of 14%. And with wind speeds maxing out at 3.6 m/s (~8 mph), it surprises me that the machine generated anything at all.

Regards,
Thomas O. Gray
American Wind Energy Association
www.awea.org
www.ifnotwind.org

 
At 4:04 PM, Blogger rdv said...

Hi Tom,

Your opinion is far less "amateur" than mine!

Yes, the capacity factor is extremely low.

For a turbine nominally rated at 300kW, do you know what wind speed that would assume?

And when groups like AWEA talk about the amount of installed capacity in the U.S., does that assume a particular capacity factor, or is that assuming all turbines operating at maximum potential? (I believe there's a duty cycle factor involved there somewhere; is it adjusted per site for the numbers that go into the national total?)

 
At 5:15 PM, Blogger Tom Gray said...

Hi Rod,

For a turbine nominally rated at 300kW, do you know what wind speed that would assume?

Sorry, no, I don't. I'll guess maybe something like 12 mph (5 m/s).

And when groups like AWEA talk about the amount of installed capacity in the U.S., does that assume a particular capacity factor, or is that assuming all turbines operating at maximum potential? (I believe there's a duty cycle factor involved there somewhere; is it adjusted per site for the numbers that go into the national total?)

No, there is no adjustment. We would just be using the "nameplate" (maximum) capacity of the turbines (that is, we would count the turbine you mention at 300 kW). Interestingly, this subject came up yesterday in a conversation with a colleague. Germany has been the world leader in installed capacity for a while now, but although its installed wind capacity is roughly double that of the U.S., we are actually not far behind in kWh generated because our wind speeds are better. AWEA estimates total electricity production annually for the U.S.--for 2006, our estimate is 25 billion kWh, which amounts to an average capacity factor of 31%.

Regards,
Tom

 

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