March 2008

Water, Thanks to Wind

One water agency will save millions with green renewable power.

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By David Engle

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Steady Electric Rates
First, some background. In 1999—shortly after energy deregulation arrived in Maryland—Taylor took WSSC into a consortium of 16 local government agencies to pool their kW–buying and to obtain power at low, fixed rates. For several years of this, he says, the consortium could save about 3%.

“That was okay,” he notes, and so too was the assured pricing; everyone still recalls what happened to the state of California, around that time. However, “what was missing” from this flat-rate deal, he says, “was any incentive to do load shaving that would save some real money,” by rewarding the agency for curtailing or shifting usage at peak-rate times.

So, WSSC broke away from the consortium and signed on with one of the newly emerging, post-deregulation retailers specializing in shopping in the new markets—a firm called Constellation Energy (www.constellation.com) buys power wholesale, and sells electricity to about 10,000 commercial and industrial accounts in the 17 deregulated states.

Now, as Taylor recalls, things got interesting. Through an existing energy performance contract, Constellation offered WSSC an opportunity to supply the bulk of its 22-MWh annual load via real-time energy purchases. With WSSC and Constellation formulating the strategy, the contract guaranteed better savings than a simple bid.

As Taylor (a certified energy manager) recalls, “on the wholesale level, we could buy on the PJM [the grid for Pennsylvania, New Jersey, and Maryland] … and supplement this with block purchases to stabilize price fluctuations on a long-term basis. This would give us the creativity to load-shift, by scheduling certain plant operations in the off-peak hours. It gave us the advantage of market timing, where we could buy blocks for [variable periods] —a year, to six months, or three months,” he says. “We could take advantage of opportunities in the market to buy blocks.

Lots of Buying-Power
Purchasing energy on the hourly market is usually the cheapest way to go, over the long run, says Taylor; but it also carries the most risk.  Overall, though, WSSC’s price risk is being reduced by buying blocks of power 24 hours a day, seven days a week—for months or years in advance. Having such flexibility hedges much of the risk of gyrations in the hourly real-time market. Taylor notes that, “By varying the lengths and sizes of the blocks, the risk is further mitigated by not putting all your eggs in one basket.” The presence of many buyers and sellers in wholesale markets makes the spot—or block-pricing very competitive, he adds.

Managing such fine points is the role of Constellation, which happens to be one of the larger players in the North American energy market. But, notes Taylor, dozens of other such firms, spun-off from local “gas and electric” utilities, can be called upon for quotes too. This enables him to check periodically whether his vendor is still giving him comparatively good deals. During this period, Taylor focused his skills in sizing his block purchases on WSSC’s average loads over a given time period. The agency’s major power-gobblers are its seven water and wastewater plants, but the loads are relatively stable, because the plants operate 24 and seven.

Constellation also assists in optimizing calculations by downloading and charting WSSC’s hourly energy consumption data. The firm’s mid-Atlantic regional vice president, Martha Duggan, explains: “We look at every hour of energy consumption and the patterns when the consumption happens,” particularly to identify opportunities to load-shift. This helps a client figure-out “how to flatten those demand peaks,” as well as helping Taylor better appreciate various risk tradeoffs. Taylor receives graphs of the load profiles several times yearly, to help refine the accuracy of budgeting and estimating. In a three-year period of buying power this way, WSSC obtained a total of 18 major blocks, of sizes ranging from 2 MW to 17 MW, and of lengths varying from a few months to two years. In its current fiscal year, WSSC will spend $21 million on electricity. Next Page >

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