RTO Insider has two interesting posts this week about doings inside PJM.
Exelon is whining about wind power driving down the wholesale price of electricity into negative territory in times of high wind and low demand. Nuke plants have to run all the time, so to keep from damaging their equipment nuke owners like Exelon have to actually pay for the privilege of selling electricity into PJM’s markets. It’s funny to see an industry for which the US taxpayers pick up the liability insurance bill whining about subsidies to wind farms.
The really interesting post, however, is the story of the tiny hydro generation that PJM just approved by FERC.
PJM’s newest hydropower project will be barely large enough to power nine homes. But if some visionaries have their way, it will be the start of a trend that could add up to a substantial new power source.
The North Wales Water Authority in suburban Philadelphia won Federal Energy Regulatory Commission approval last month for an 11-kW turbine and generator to capture the energy from a 12-inch water line.
North Wales’ project is among 19 projects approved by FERC since September under legislation enacted last year that a Department of Energy study says could unlock 12 GW of capacity at existing non-powered dams and manmade water conduits, including about 1.5 GW in PJM.
Yup, you read that right. The Philadelphia water company is generating electricity inside its pipes at locations where there is significant downhill drop in its water lines.
The North Wales project is one of three approved thus far in PJM.
Ellwood City, a town 40 miles north of Pittsburgh, won approval for a 10-kW turbine on a 24-inch wastewater pipe that discharges 1.7 million gallons of water daily. The Pelton wheel turbine would use the momentum of the 50-foot “head” — or drop in elevation — in the 340-foot pipe.
Another project that won approval is a 250-kW project by Oak Lawn, Ill., a Chicago suburb, which will install a turbine in a drinking water pumping station.
Oak Lawn buys water from Chicago’s purification plant, storing it in eight reinforced concrete reservoirs. Water must be delivered to the reservoirs through an air gap to prevent backflow into the Chicago delivery system.
Oak Lawn had been using butterfly valves to create the air gap and reduce the 45 pounds per square inch pressure. When the town began planning a major overhaul of the water system, engineers decided to replace the valves with a turbine. “Why not recapture what [energy] they can?” explained Randy Rogers, an engineer with CDM Smith Inc., which is designing the project.
The turbine and generator, about the size of a side-by-side washer and dryer, will save the town more than $160,000 annually in electricity, about 15% of what it spends powering the pumps that deliver water to its customers.
What will happen to electric companies when water companies across the US begin generating significant amounts of their own electricity? Holy moly. I’d hate to be in the centralized electrical generating business right now.