“B/C (benefit-to-cost) ratio tracks cross-seam transmission capacity: The conditions resulting in the highest cross-seam transmission capacity are the conditions having the highest B/C ratio,” the researchers wrote. The more transmission across the seam, the better, according to the researchers’ paper published this summer. McCalley said it would take an estimated $50 billion to build what researchers are calling a “macrogrid” of major transmission lines that loop around the Midwest and West, with branches filling in the middle and connecting to Texas and the Southeast. “So, for every dollar invested, you get up to $2.50 back,” said James McCalley, an Iowa State Anson Marston Distinguished Professor in Engineering, the Jack London Chair in Power Systems Engineering and a co-author of the papers. “The results show benefit-to-cost ratios that reach as high as 2.5, indicating significant value to increasing the transmission capacity between the interconnections under the cases considered, realized through sharing generation resources and flexibility across regions,” says a summary of the latest paper. Department of Energy’s National Renewable Energy Laboratory in Colorado used the 2038 data to complete an hour-by-hour model of one year of power-sharing across the seam.

The Iowa State models took the grid-improvement process up to 2038. The model includes four designs for cross-seam transmission and eight generation scenarios with differences in transmission costs, renewable-electricity generation, gas prices and retirements of existing power plants. Iowa State engineers contributed computer modeling expertise to the project, building a capacity expansion model that simulates 15 years of improvements to power generation and transmission. Researchers, including engineers from Iowa State University, shared early findings during a 2018 symposium at Iowa State and the latest findings in two papers published this summer and fall by IEEE, the Institute of Electrical and Electronics Engineers. That’s according to the Interconnections Seam Study, a two-year, $1.5 million study launched as part of a $220 million Grid Modernization Initiative announced in January 2016 by the U.S. So, up to 1,320 megawatts isn’t much electricity moving between the two.īut what if there were bigger connections between the two grids? What if more power moved back and forth? Could that move Iowa wind power, Southwest solar power and Eastern off-shore wind power from coast to coast? Could the West help the East meet its peak demand, and vice versa? Would bigger connections boost grid reliability, resilience and adaptability? Would the benefits exceed the costs? Texas, with its own grid, is mostly outside the two big grids.)Īnd they are big grids – the eastern grid has a generating capacity of 700,000 megawatts and the western 250,000 megawatts. (The seam separating the grids runs, roughly, from eastern Montana, down the western borders of South Dakota, Nebraska and Kansas and along the western edges of the Oklahoma and Texas panhandles. Those seven threads (technically, they’re back-to-back, high-voltage, direct-current connections) join America’s Eastern and Western interconnections and have 1,320 megawatts of electric-power handling capacity.

Department of Energy's National Renewable Energy Laboratory.ĪMES, Iowa – Two of the biggest power grids on the planet are connected by seven small threads. Map courtesy of the Interconnections Seam Study, the U.S. This map shows how a macrogrid (the red lines) could cross the seam separating the Eastern and Western interconnections, allowing most of the country to share electricity, including Midwest wind energy and Southwest solar energy.

Us power grids map