Wärtsilä has been contracted to supply a 56 MW Smart Power Generation power plant to the Stillwater Utilities Authority (SUA) in Oklahoma, USA. The contract was signed in September 2014 and the equipment delivery will begin in November 2015.
The power station will be used to balance wind and solar generation in Oklahoma. “When the wind stops blowing and the sun goes down, we need to keep up the load. Quick-starting engines are perfect for this,” SUA’s Director Dan Blankenship said. The plant will also be used for peaking power.
The new plant will replace a 26 MW gas turbine built in the 1950s. The main reason why SUA opted for internal combustion engine (ICE) technology was operational flexibility. “It takes eight hours to start our current capacity. Smart Power Generation can go from start-up to full load in just ten minutes,” Dan Blankenship said. The plant will consist of three Wärtsilä 50SG engines, running on natural gas.
Operational flexibility is also appreciated because of the changing market environment in the area. In March 2014, Southwest Power Pool (SPP), the regional transmission organization, took over the dispatch of electric generation for all regional generators in Oklahoma. SPP determines on a daily basis which units will be operated to meet electricity demand most efficiently and reliably. Stillwater’s former inefficient capacity has been called upon only as spinning reserve.
“With new, fast-reacting capacity, we expect to be dispatched more often. We will rank better in the merit order and get more running hours,” Blankenship said.
Gary Groninger, Business Development Manager for Wärtsilä, said: “This plant will provide maximum operational flexibility and the highest simple-cycle operating efficiency in the industry. The plant will provide unmatched benefits to the Stillwater community for the decades to come.”
Oklahoma has more than 1700 active wind turbines with over 1300 MW capacity, and ranks sixth among all American states. Wind farms provided 14.8 percent of Oklahoma’s electricity in 2013 and can power the equivalent of more than 1,000,000 average American homes. The capacity of grid-connected solar panels is still relatively small, but is growing rapidly – by 133 percent in 2013 alone. (Sources: American Wind Energy Association and Interstate Renewable Energy Council.)
Wärtsilä has years of experience in supporting wind farms with power plants in the 200 MW range in Texas and Colorado. A new 225 MW wind-integrating power station is under construction in Oregon. Wärtsilä’s total capacity in the United States is some 2400 MW.
According to a recent report by the International Energy Agency (IEA), internal combustion engines are a promising technology for supporting wind and solar energy. Comparing different flexibility resources for power systems, IEA says gas-fired ICE power plants are a ”very mature technology” and ”cost-competitive to OCGTs” (Open Cycle Gas Turbines). The IEA notes that “growth in ICE plants actually exceeds that of turbine-based technologies”. According to the IEA, the key asset of engine-based generation is fast starting and ramping capability. The findings were published in IEA’s Energy Technology Perspectives 2014.