WEST LAFAYETTE, Ind. — A future where all homes and vehicles in the U.S. are fully electrified could overwhelm power supply and risk outages unless key upgrades are made, says a new study conducted by Purdue University engineers. But a few strategies could cut two-thirds of the potential costs of reinforcing the nation's distribution grid to handle this demand.
Electrifying would mean switching a home's heating system from a boiler to a heat pump and transitioning from gas- or diesel-fueled vehicles to electric vehicles.
"If we install a whole bunch of new electric heating systems for homes and use more electric vehicles and electric water heaters, then we're going to increase electricity demand a lot. And that's basically going to require putting in thicker wires, bigger transformers and other infrastructure into the power grid," said Kevin Kircher , a Purdue assistant professor of mechanical engineering and faculty member in the university's Ray W. Herrick Laboratories . "And if that happens, utilities will pass the cost of those upgrades to us, the customers."
The study, published in Cell Reports Sustainability on Sept. 16, found that reinforcing the U.S. distribution grid, which provides power to residential areas, could cost $350-$790 billion — about $2,000-$6,400 total per household between now and 2050. Much of this cost would be due to increased electric space heating , with the coldest regions of the U.S. experiencing electricity demand peaks up to five times higher than today's peaks.
But taking measures such as installing better insulation and air sealing, improving equipment efficiency, and coordinating the operation of the home's electric devices could mitigate the costs of upgrading the grid.
An example of boosting the efficiency of the home's electric equipment would be using ground-source heat pumps instead of air-source heat pumps because the constant ground temperature reduces the energy needed to heat and cool homes. Coordinating the home's electric device operation could mean adjusting when the home's electric vehicle charges so that it doesn't happen at the same time when the heat pump is in use.
"If electric vehicles could communicate with the heating, ventilation and air conditioning units that we install in the house, and if they can coordinate when they have to charge or when they have to heat or precool the homes, this strategy could contribute to a 40% decrease in grid reinforcement costs," said Priyadarshan, a PhD student in Purdue's School of Mechanical Engineering and the first author of this paper. "Let's say there's a cold snap coming. The heat pump could preheat the house, and the home's electric vehicles could be charged at a different time to reduce strain on the grid."
The study focused on each county of the Lower 48 U.S. states. The researchers modeled the grid impacts of fully electrifying homes and vehicles using public surveys of home electricity usage and electric vehicle travel where available for each county, specifications from equipment manufacturers, building code guidelines, and weather data. The team also calibrated the home data against a fully electrified test house in West Lafayette called the DC Nanogrid House .
After analyzing the impact of full electrification to the distribution grid, the researchers adjusted the parameters of their model to include the home weatherization and equipment efficiency strategies they were proposing to cut grid upgrade costs. For their strategy to coordinate electric device operation, they used an optimization algorithm to take into consideration heating, electricity demand and electric vehicle usage and devise an optimal solution for when to charge the vehicles and how hard to run the heat pumps.
Other studies have investigated the future of increased home and vehicle electrification in the U.S. but not on the scale of residential areas by county nationwide.
"On the one hand it's kind of scary — if we electrify everything, we might have a crazy expensive future. But on the other hand, if we electrify in a smart way, then we don't have nearly as many of those problems," Kircher said.
This study was funded by Purdue's Center for High Performance Buildings .
