Feb 22 2017
Credit: University of Delaware
Scientists at the University of Delaware and Princeton University have completed a first-of-its-kind simulation with the electric power industry. According to the scientists injecting large quantities of offshore wind power into the electrical grid in the U.S. is manageable, and it will reduce electricity costs and minimize pollution compared to existing fossil fuel sources.
The scientists discussed with PJM Interconnection, a grid operator supplying electricity to over 60 million people in 14 states, to make a computer model to simulate how the electric grid would respond to wind power injections from offshore wind farms along the East Coast at five developmental stages, between 7 and 70 gigawatts of installed capacity. This two-part study is published in the Renewable Energy journal.
One difficulty that grid operators face is how to incorporate large quantities of naturally fluctuating offshore wind into a network that has to provide reliable power to customers, 24/7.
The research team from the UD and Princeton University conservatively revealed that, with some upgrades to transmission lines without any requirement for added storage, the PJM grid can manage more than 35 gigawatts of offshore wind - that is 35 billion watts - to power a projected 10 million homes.
The researchers also found that the PJM grid may handle twice that amount (up to 70 gigawatts) as wind forecasting improves, enabling the power operator to better forecast and harness more wind.
Our goal was to replicate this very human-made energy system under all kinds of scenarios. What would you do as a grid operator if you thought it was going to be windy today and it isn’t, or if the wind storm arrives earlier than expected? We simulated the entire PJM grid, with each power plant and each wind farm in it, old and new, every five minutes. As far as we know, this is the first model that does this.
Cristina Archer, Associate Professor, University of Delaware
From her office in the Harker Interdisciplinary Science and Engineering Laboratory at UD, Archer led the team’s effort to produce accurate offshore wind forecasts derived from real wind farm data from land-based systems, which the Princeton collaborators integrated into their PJM electric power system model.
The research team used stochastic modeling to run hundreds of forecasts with several tweaks in conditions in order to realistically represent both the fluctuating and unpredictable behavior of wind.
The PJM model, created at Princeton, is called Smart-ISO. It is designed to handle both the uncertainty and variability of growing inputs of offshore wind energy, and simulate what happens over a widespread power grid with transmission lines of more than 60,000 miles.
“The uncertainty of wind will require that we develop strategies to minimize the need for spinning reserve,” said Warren Powell, professor and lead researcher at Princeton in charge of the SMART-ISO model, concerning electric generators that need to keep “spinning” and be ready for any power shortages. “Although we found that reserves were needed — 21 percent of the 70 gigawatt wind capacity — there are a number of strategies that could be investigated to better handle the variability as wind grows in the future.”
When the researchers started their study five years ago, the first U.S. offshore wind farm, comprising of five turbines at Block Island, Rhode Island, with a capacity to generate 30 megawatts, had not yet been constructed. The 70 gigawatts offshore wind farm, modeled in this study, would be nearly equal to total U.S. wind power-generating capacity installed on land in 2016.
According to Archer, adding more offshore wind farms would reduce electricity costs of consumers and minimize pollution by replacing both coal and natural gas power plants.
We saw up to a 50 percent reduction in carbon and sulfur dioxide and up to a 40 percent 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. Wind power is a very good idea - for people’s health and their wallets.
Cristina Archer, Associate Professor, University of Delaware
The research was supported by the U.S. Department of Energy.
The two-part study is published in Renewable Energy. Part I, “The Challenge of Integrating Offshore Wind Power in the U.S. Electric Grid: Wind Forecast Error,” was written by Cristina Archer, H. P. Simao, Willett Kempton, Warren Powell and M. J. Dvorak. Part II, “The Challenge of Integrating Offshore Wind Power in the U.S. Electric Grid: Simulation of Electricity Market Operations,” was written by H.P. Simao, Warren Powell, Cristina Archer and Willett Kempton.