“For us, a lot of options have turned into not many options,” said Ms. Nelson, 39, who has been looking for a bigger home for her family of six. With prices rising faster than Mr. Nelson’s salary as an engineering tech worker, the Nelsons say they may have to leave the state for cost reasons. “We don’t want to go, but just not sure if we can stay,” Ms. Nelson said.

Tensions over the growing population and shifting economy were already high two years ago when the solar project first came along. Fault lines quickly emerged. The area’s chamber of commerce, for example, endorsed the project, while the county board of commissioners supported a moratorium on commercial solar projects on prime farmland.

Opponents of the solar project have a shorthand line of attack: Seattle is pushing this.

“The wind farms aren’t located in the greater Seattle area, the wolves aren’t located in the greater Seattle area, the grizzly bear expansion isn’t slated for the Greater Seattle area, and the solar farms aren’t there either,” said Paul Jewell, a former county commissioner, ticking off highly debated initiatives that government officials have considered in recent years.

“They’re all in the rural areas,” said Mr. Jewell, who opposes the solar project. “And so there’s really a disconnect there — they say ‘yes,’ and we bear the burden. They say ‘yes,’ and we pay the price.”

Geography aside, conservatives and liberals have lined up on both sides of the solar question. Ronald Slater, a retired contractor and a supporter of President Trump, was so eager to get solar panels on his land that he handed out business cards at a recent county meeting. Carla Tacher, who manages a fruit and vegetable stand outside Ellensburg and said she leans toward Democrats, said that more renewable energy — far easier to produce in the sunnier weather east of the Cascades than in the western half of the state — is crucial for the global climate.

“I’m all for it,” Ms. Tacher said.

Broader political questions are on the horizon in November, when voters in Kittitas County will pick a successor to Dave Reichert, a seven-term Republican who is retiring. The county is a conservative anchor of the Eighth Congressional District, which extends west to more liberal suburbs of Seattle. Mr. Reichert, a right-of-center moderate on most issues, won the district in 2016 with significant support in Kittitas. But Hillary Clinton carried the district in the presidential race, as Barack Obama did in 2008 and 2012, so both parties see the House seat as winnable — and crucial to their control of the next Congress.