Washington’s main natural gas pipeline network is running close to capacity during periods of high demand, prompting Williams Companies to advance four projects that could increase the amount of gas moving into the state. The proposals range from compressor upgrades on existing lines to new pipelines in Eastern Washington and along the Columbia River Gorge. Two have federal authorization, while two remain in earlier planning or customer discussions. Williams says the projects are intended to serve short periods of peak demand, not to increase gas use throughout the year. The strain became apparent during a January 2024 cold snap, when the Northwest Pipeline moved about 4.5 billion cubic feet of gas in one day — roughly 16% above its designed capacity. A major underground storage facility near Centralia was also offline, and Williams asked some large customers to cut their gas use. The Northwest Gas Association has reported that interstate pipelines in the region averaged more than 95% utilization in the five years through 2024. Gas use by Washington power plants rose about 45% over the past decade, according to federal data. Electricity demand is also expected to grow as data centers, electric vehicles and heat pumps add load to the grid. Utilities and energy analysts say gas-fired plants can provide backup during winter periods when wind and solar output is low, though Williams’ proposals are not publicly linked to specific customers. The largest proposal, the Rockies Columbia Connector, could bring additional gas from the Rocky Mountains through Idaho to Washington and Oregon. Williams has set a 2030 service target for its first phase to Idaho. The company said it was still discussing a possible second phase with customers in Washington and Oregon and had no further update. Earlier plans described about 158 miles of new pipeline near existing lines along the Columbia River Gorge. A separate proposal, Valley Trail, could extend service toward Quincy in Grant County. An earlier Williams presentation showed 137 miles of 30-inch pipeline in Eastern Washington, including about 63 miles on a new route toward Quincy. That presentation listed a 2026 federal application and 2028 service date, but Williams has since said those dates are no longer accurate and provided no revised timeline. Quincy is a major data-center hub, and data centers already account for about 37% of Grant County Public Utility District’s electricity use. The utility is seeking more power generation as it considers growth in demand, but Williams has told a Spokane television station that data-center growth is not driving its Valley Trail plans. Data centers can nonetheless increase gas demand indirectly if additional electricity use leads utilities to rely more on gas-fired generation. The two projects with federal authorization largely use existing pipeline infrastructure. The Huntingdon Connector would upgrade compressors to move more gas south from the Canadian border along the Interstate 5 corridor; Williams has said it could enter service in 2026. The Kelso-Beaver project would increase flows between the Northwest Pipeline and an Oregon storage facility, with service targeted for 2028. How much these projects would add to Washington’s climate emissions would depend on how much of the gas is ultimately burned. Williams has pointed to forecasts showing relatively flat annual gas use for power generation across the Western U.S. through 2035, even as demand on peak days rises. Environmental advocates argue that infrastructure built for peak demand could still extend the region’s dependence on fossil fuels. Audrey Leonard, a staff attorney with Columbia Riverkeeper, said utilities could address peak demand through measures such as reducing data-center electricity use at certain times and improving energy efficiency. She said the proposals would face opposition from affected communities and groups that have long challenged fossil-fuel projects. The Federal Energy Regulatory Commission generally has the leading approval role because the Northwest Pipeline crosses state lines. State agencies and local governments may also regulate permits for water, air pollution, construction and land use. Williams has not publicly identified the customers behind the proposed capacity. If utilities sign long-term contracts, they could seek to recover pipeline costs through customer bills, meaning ratepayers may ultimately bear some of the expense.