The scientists consulted with PJM interconnection – a grid operator supplying electricity to more than 60 million people in 14 states, to introduce a computer model that simulates how the electric grid would respond to injections of wind power from offshore wind farms along the East Coast at five build-out levels, between 7 to 70 gigawatts of installed capacity.
One constraint grid operator’s face is how to integrate enhancing volumes of naturally fluctuating offshore wind into a network that has to deliver reliable power to customers, 24-7. The UD and Princeton group revealed conservatively that with some upgrades to transmission lines but without any required for additional storage, the PJM grid can handle over 35 gigawatts of offshore wind that is 35 billion watts, enough to power an estimated 10 million homes.
They also identified that the PJM grid could in the future handle twice that volume, up to 70 gigawatts, as wind forecasting enhances, enabling the power operator to better predict and harness more wind.
“Our aim was to substitute this very man-made energy system under all sorts of scenarios,’ says Cristina Archer, associate lecturer of physical ocean science and engineering at the University of Delaware. “What would you do as a grid operator if you thought it was going to be windy today and it is not, or if the wind storm arrives earlier than expected? We augmented the entire PJM grid, with each power plant and each wind farm in it, new and old, every five minutes. As far as we know, this is the first model that does this.”
From her office in UD’s Harker Interdisciplinary Science and Engineering Laboratory, Archer led the group efforts to generate realistic offshore wind forecasts based on real wind farm information from land-based systems, which team members at Princeton then incorporated into their model of the PJM electric power system. The group employed stochastic modelling, running hundreds of forecasts with numerous tweaks in conditions, to realistically represent the fluctuating and sometimes unpredictable behaviour of wind.
The model of PJM, known as Smart-ISO, prepared at Princeton, is designed to handle both the uncertainty and variability of growing inputs of offshore wind energy, simulating what happens over an extensive power grid with more than 60,000 miles of transmission lines.
Archer says that complementing more offshore wind farms would lower consumer’s electricity costs and reduce pollution by substituting natural gas and coal power plants. “We saw up to a 50% reduction in sulphur and carbon dioxide and up to a 40% reduction in nitrogen oxides emissions at the highest build-out level, a 70 gigawatt set of wind farms. Plus, the costs of electricity would go down every month except in July when air conditioning is at a peak.” says Archer.
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