|
Making more use of Fire Island wind
System in place allows MEA to buy wind power in excess of what Chugach Electric Association uses, which typically occurs in summer
Alan Bailey Petroleum News
Chugach Electric Association and Matanuska Electric Association have successfully implemented a technique that enables MEA to make use of excess power from the wind farm on Fire Island, offshore Anchorage, officials from the two Southcentral Alaska electric utilities told a meeting of the Regulatory Commission of Alaska on Dec. 12. Excess power comes available when Chugach Electric cannot make use of all of the wind farm output.
Chugach Electric is the only utility to have contracted to purchase power from the Fire Island facility, which is owned by Cook Inlet Region Inc. But the power output from the facility is extremely variable, changing along with the varying strength of the wind at Fire Island. If the amount of wind power exceeds what Chugach Electric can use, the output has to be curtailed, thus wasting a valuable energy resource and wasting the cost of the unused power.
Excess power offered for sale Under a new arrangement that Chugach Electric and MEA have been successfully testing, Chugach Electric has set up a display in its dispatch center, showing the difference between the wind power that is available and the amount of wind power that the utility is actually using, Brian Hickey, vice president of systems operations for Chugach Electric, told the commission. This display also shows up in MEA’s control system, he said. If MEA has capacity to take that excess power, it calls Chugach Electric and offers to take some amount of wind power at some offered price.
The procedure operates in the form of what is referred to as an economy energy transaction, a commonly used form of transaction in which the Alaska Railbelt utilities buy and sell each other’s power. In this type of transaction, the two utilities normally split the savings between each other, Hickey said. The power has to be sold at more than its cost and at less than what it would cost to replace, commented Ed Jenkin, director of power delivery for MEA.
Handling the variable power The challenge with an energy sale of this type is the variability of the wind power. Depending on the amount of wind power that Matanuska Electric takes relative to amount of power specified in the purchase agreement, either Chugach Electric or MEA has to regulate the wind power, counterbalancing the varying power with varying amounts of power from other generation facilities. And the power variations cause “inadvertants,” power transfers that diverge from the volumes in the purchase agreement. Those inadvertants are tracked and paid back as part of the accounting for the next day.
“So there’s a fair amount of energy accounting going on in the background to make this happen, and combining the real-time nature of the wind was quite challenging,” Hickey said.
The utilities anticipate using the new protocol mainly during the summer, when electricity demand tends to be low but when the wind can, nevertheless, blow quite strongly at Fire Island. And the system has been set up, so that it could also be used by Homer Electric Association and Golden Valley Electric Association, two other Railbelt utilities, Hickey said.
|
