Want lower emissions? Build more transmission, PNNL says (original) (raw)

If all the high-voltage transmission currently under construction and in advanced stages of permitting is built by 2030 in the Western U.S., enabling the construction of new renewable energy projects, carbon dioxide emissions in the Western United States could drop by 73% compared to 2005, according to a new report from the Department of Energy’s (DOE) Pacific Northwest National Laboratory (PNNL).

Energy generation costs would also decrease 32% by 2030, compared to a reference case where most of these projects are not built, PNNL argued,

The report, Western Interconnection Baseline Study, examines how new transmission and renewable energy projects in the Western United States could bring economic benefits and reduce carbon dioxide emissions. The report is part of the National Transmission Planning Study, funded by DOE’s Grid Deployment Office.

“The Western Interconnection Baseline Study uses the grid industry’s most reliable data to look at how future transmission and renewable energy projects would lower carbon emissions and save money, all while keeping the western grid stable and reliable,” said Konstantinos Oikonomou, a staff power systems research engineer at PNNL and lead author of the study.

The U.S. has more than 700,000 miles of transmission lines, but DOE has been studying how adding more transmission could help integrate more renewable energy, lower the cost of energy generation, and decrease carbon emissions from grid operations. In support of this effort, a PNNL team conducted a baseline analysis considering only the impact of major new transmission projects that are in the pipeline for the Western Interconnection, the electrical grid that powers 16 western states and two Canadian provinces.

A model for more transmission

The research team built a model of the Western Interconnection that incorporated 12 transmission projects currently in advanced stages of development or permitting. These 12 projects would add more than 3,000 miles of new transmission, connecting places like Wyoming to southern California, Nevada, and western Arizona.

Next, the researchers updated the model with wind, solar, and storage projects that would likely be built to take advantage of new transmission capacity. As of July 2024, the Western Interconnection hosts 30 GW of wind power, 38 GW of solar, and 14 GW of storage. In the scenario outlined in the report, the region would see an additional 35 GW of wind, 31 GW of solar, and 12 GW of energy storage by 2030.

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The team then simulated a typical year of energy demand and generation with the new model. This included conditions like electricity demand and generation rising and falling due to the time of day, temperature, and weather conditions.

The researchers say their model showed that adding more cheap renewables to the grid by 2030 would displace 15% of the generation output of existing fossil power plants, reduce carbon dioxide emissions by 73% (compared to 2005 levels), and drop the price of generation by 32%. The new transmission lines would also allow states like California to import wind energy from states like New Mexico and Wyoming, the report said.

Preparing for the worst

The research team also wanted to analyze how the hypothetical future Western Interconnection could deal with failure. This came in two forms: loss of power generation and loss of transmission.

The team simulated both failures on July 29, 2030, at 4 p.m., as previous analysis suggested that demand peaks mid-summer with air conditioner use, and solar power begins to dip in the late afternoon as the sun sets.

In the first scenario, an Arizona nuclear plant loses two generating units, which could lead to outages for thousands of customers. The researchers found that in their hypothetical grid with a high proportion of renewables, energy storage systems would kick in to alleviate some of the burden and provide stability.

In the second scenario, a transmission line delivering 3,100 MW from southern Oregon to northern California fails. In this case, as well, the grid remains stable with the new transmission lines supporting the existing network, which would reroute power through alternative paths PNNL said.