March 2008

Water, Thanks to Wind

One water agency will save millions with green renewable power.

Article Tools

Create a Link to this Article

By David Engle

Comments


The downside here would be a fall in either green or brown energy prices, rather than a rise. But, here, current market forces suggest that if anything, wind will grow costlier. First, construction and wind turbine manufacturing costs are rising. Second, regional utilities are scrambling for whatever green power is available, to meet REP mandates.

Historically, for the past few years, both green and brown power rates have been climbing about 10%. Thus, when WSSC’s wind power farm comes on-stream, sometime in 2008, its 6.4 cents-per-kilowatt-hour price will almost certainly be cheaper than conventional wholesale power rates, which were about 6.5 cents per kilowatt-hour, in autumn 2007, Taylor reports.

Even in the unlikely event of a price drop, this would be quite acceptable after all, because the wind-power portion comprises only one-third of the agency’s total need anyway. Thus, the remaining two-thirds of the agency’s purchases would be enjoying a sudden “windfall” of lower prices.

If It’s So Great, Why a Third?
This fraction actually reflects one of the complicating equations of wind power—namely, its sometimes wild variability. Although the pricing is rock-steady, the big question mark is always output. Sometimes it blows at gale force; at other times it’s in the doldrums. WSSC’s agreement to buy 85% of the power, effectively translates into committing to purchase at least one-third of the farm’s energy all the time, day or night. In this case, this means about 8 MW of the allotted 24 MW maximum, on a continuously averaged basis.

That 8 MW is a modest and consistently usable output. However, if Somerset County should enjoy fair breezes and the farm manages to rev-up to its rated capacity, then WSSC will be obligated to buy 85% of this surplus as well. At the upper production limit, the total would come to, again, 24 MW. This would still be usable much of the time, but edges close to the margin, depending on the hour and season. If WSSC had committed to buying more wind, there might be more times when this would be yielding an excess (as on windy nights). WSSC would then have to sell the surplus.

Impact on Brown-Energy Blocks
What if the wind output is low? Taylor replies that, during such times (likely to occur especially during the summer), he has already charted-out graphs defining conventional purchases to be made. “Instead of buying a single block of power, you’re now buying two—a ‘green’ block and a ‘brown’ one,” he says. The wind-produced energy arrives at a consistent price, but is quite variable in terms of megawattage. To compensate, WSSC “will probably buy two sizes” of conventional brown power, he adds, “to keep it simple.” One block will be sized to provide whatever the wind power doesn’t. Then, if this purchase turns out to be a bit low, the difference every month will be adjusted by buying more on the spot market. And again, all the while, WSSC will do load-shifting. If this demand-response strategy leaves WSSC receiving too much power, the surplus can be readily sold back to the PMJ grid at the prevailing price.

These modest transactions will occur automatically via Constellation’s marketing service. All in all, coordinated green-and-brown buying should save WSSC an estimated $14 million over the contract term. Next, additional millions in cost-avoidance will be realized, calculated from the wind’s value in the RECs that WSSC will accrue.

Currently, in Maryland these are valued at about two cents per kilowatt-hour. Were it not for WSSC’s wind purchase, the agency would easily spend $7 million or more for RECs needed to meet assorted clean–generation targets, Taylor says. REC values will also likely rise, as utilities press to meet REP standards. Next Page >

What Do You Think?

Post a Comment

Be the first to tell us what you think!

Post a Comment

Not a subscriber? Sign Up
 
 
*  
 




 

Get Water Efficiency Email Updates!

Get weekly news and updates through our Water Efficiency email newsletter!