One solution to U.S. grid expansion minimizes costs and emissions. The other maximizes reliability.

Demand for electricity is increasing. electric grid will need to expand in response. But there’s a tradeoff between cost and reliability in doing so, according to a new study. The study is a rare instance of scientific analysis focused on a pending piece of federal legislation.

Researchers used a well-known computer model of energy generation to investigate the effects of two different policies to guide electrical transmission infrastructure. One of the two scenarios is in line with the BIG WIRES Act, which would require each regional grid to be able to send at least 30% of its peak load to other regions by 2035.

Inter-regional transmission is important especially for a decarbonized grid, because the locations with the best renewable energy resources are not necessarily the locations where electricity needs are highest. Planning for grid infrastructure usually happens at the regional level, though, and transmission between regions has been slow to develop – so federal lawmakers have begun to step in.

The researchers analyzed how the legislation would affect grid costs, emissions, and reliability compared to a policy scenario focused on building out grid infrastructure in areas with more renewable energy resources, such as wind power in the central U.S. Focusing grid expansion on areas with renewable resources would minimize costs and – because solar and wind power are now so cheap – would minimize emissions as well, the researchers found.

.IRPP_ruby , .IRPP_ruby .postImageUrl , .IRPP_ruby .centered-text-area {height: auto;position: relative;}.IRPP_ruby , .IRPP_ruby:hover , .IRPP_ruby:visited , .IRPP_ruby:active {border:0!important;}.IRPP_ruby .clearfix:after {content: "";display: table;clear: both;}.IRPP_ruby {display: block;transition: background-color 250ms;webkit-transition: background-color 250ms;width: 100%;opacity: 1;transition: opacity 250ms;webkit-transition: opacity 250ms;background-color: #eaeaea;}.IRPP_ruby:active , .IRPP_ruby:hover {opacity: 1;transition: opacity 250ms;webkit-transition: opacity 250ms;background-color: inherit;}.IRPP_ruby .postImageUrl {background-position: center;background-size: cover;float: left;margin: 0;padding: 0;width: 31.59%;position: absolute;top: 0;bottom: 0;}.IRPP_ruby .centered-text-area {float: right;width: 65.65%;padding:0;margin:0;}.IRPP_ruby .centered-text {display: table;height: 130px;left: 0;top: 0;padding:0;margin:0;padding-top: 20px;padding-bottom: 20px;}.IRPP_ruby .IRPP_ruby-content {display: table-cell;margin: 0;padding: 0 74px 0 0px;position: relative;vertical-align: middle;width: 100%;}.IRPP_ruby .ctaText {border-bottom: 0 solid #fff;color: #0099cc;font-size: 14px;font-weight: bold;letter-spacing: normal;margin: 0;padding: 0;font-family:'Arial';}.IRPP_ruby .postTitle {color: #000000;font-size: 16px;font-weight: 600;letter-spacing: normal;margin: 0;padding: 0;font-family:'Arial';}.IRPP_ruby .ctaButton {background: url(https://www.anthropocenemagazine.org/wp-content/plugins/intelly-related-posts-pro/assets/images/next-arrow.png)no-repeat;background-color: #afb4b6;background-position: center;display: inline-block;height: 100%;width: 54px;margin-left: 10px;position: absolute;bottom:0;right: 0;top: 0;}.IRPP_ruby:after {content: "";display: block;clear: both;}Recommended Reading:This elegant solution to expanding the grid costs half as much as building new power lines The tradeoff is relatively small in percentage terms, but involves huge sums of money, a reflection of just how massive the U.S. electric system is overall. Grid expansion focused on areas with strong renewable resources saves $1.52 billion (1.13%) and 28.6 million metric tons (3.65%) of carbon emissions annually compared to the approach reflected in the BIG WIRES Act.

(Both scenarios save money and carbon emissions compared to the status quo.) But the BIG WIRES approach would yield bigger improvements in grid reliability, reducing the number of power outages due to extreme weather. (When grid expansion instead focuses on areas with strong renewable energy resources, the effects on reliability vary by region.) The finding was surprising at first, says study team member Juan Senga, a postdoctoral researcher at the Massachusetts Institute of Technology.

But the team realized it was an inherent result of more inter-regional connections. “That s the key – if regions can import power from everywhere else, then there is more room to help each other out during periods of stress which improves reliability,” he says.

With capacity for 30% inter-regional connectivity, the number of outages due to extreme cold would decline by 39% compared to today’s grid, the team found. The team is now analyzing policy strategies to streamline permitting for transmission infrastructure. “There s a lot of case studies around the reasons for delays, but we want it to be more data-driven and analytical. Our next work tries to provide that rigorous analysis,” Senga says.

“If we can accelerate build outs, that would be a dream!” Source: Senga, J.R.L. “Implications of policy-driven transmission expansion for costs, emissions and reliability in the USA.” Nature Energy 2025. Image: Aldward Castillo for Unsplash+.