SAN FRANCISCO — Apple has committed nearly $850 million to help build a solar energy farm in Monterey County that will generate power for its California facilities, Apple CEO Tim Cook announced Tuesday.

Speaking at a technology conference hosted by Goldman Sachs, Cook revealed that Apple is partnering with First Solar to construct the 1,300-acre plant, which he hailed as one of the tech giant’s most ambitious projects ever. Apple’s two campuses in Cupertino, data center in Newark and all 52 Apple Stores in the state will draw power from the facility, Cook said.

“We know at Apple that climate change is real,” Cook said. “Our view is that the time for talk is past and the time for action is now.”

Cook revealed the company’s plans during a wide-ranging conversation with Goldman Sachs president Gary Cohn at a financial conference hosted by the bank at the Palace Hotel in San Francisco. With shares closing at $122.02 during the address Tuesday, Apple became the first U.S. company to achieve a market value of more than $700 billion, a fact Cohn pointed out during his conversation with the Apple leader.

“You’ll remember exactly where you were when you had a $700 billion market cap,” he told a beaming Cook.

Cook noted that the solar project will drive major savings for Apple, which is committing $848 million for a 25-year lease on 130 megawatts of solar power, enough to power 50,000 homes. But he stressed that the project is driven by other aims than financial gains.

“We’re doing this because it’s right to do,” he said.

In addition to previewing the landmark solar project, Cook also took some time on the stage to reflect on the company’s achievements during the past year. In its most recent quarter, Apple raked in $18 billion in profit, the biggest haul ever for a publicly traded company. Although some analysts have questioned whether the company can continue to grow at such a rapid clip, Cook brushed aside those concerns.

“We don’t believe in such laws as laws of large numbers,” he said. “One of the things (Apple co-founder Steve Jobs) ingrained in us is that putting limits on your thinking is never good.”

Cook added that he was pleased with the debut of Apple Pay, a new mobile payments service that lets users buy items in stores by waving their iPhones. Before Apple Pay’s October release, Cook said he thought the service’s adoption would be slowed by retailers reluctant to tinker with their payment systems before the critical holiday shopping season. But many brands have been willing to give the technology a try.

“It’s going faster than I thought it would,” Cook said of Apple Pay’s adoption among retailers.

Although the blockbuster sales of the iPhone 6 and 6 Plus have garnered the most attention, Cook suggested that the company’s recent software offerings were just as significant. Last year, the company rolled out new programs to help people use iOS software in their cars and homes, in addition to monitoring their health, Cook noted.

“None of us want to have different platforms in different parts of our lives,” Cook said. “I think that is huge for our future.”

Cook stressed Apple’s commitment to the environment in his announcement of the solar farm, noting that its data centers are already powered by renewable energy, and environmental advocacy group Greenpeace cheered the announcement Tuesday.

“It’s one thing to talk about being 100 percent renewably powered, but it’s quite another thing to make good on that commitment with the incredible speed and integrity that Apple has shown in the past two years,” Greenpeace Senior IT Sector Analyst Gary Cook said in a statement. “Apple still has work to do to reduce its environmental footprint, but other Fortune 500 CEOs would be well served to make a study of Tim Cook, whose actions show that he intends to take Apple full-speed ahead toward renewable energy with the urgency that our climate crisis demands.”

Arizona-based First Solar announced the deal in a news release that included more praise for Apple.

“Apple’s commitment was instrumental in making this project possible and will significantly increase the supply of solar power in California,” First Solar Chief Operating Officer Joe Kishkill said in the release.

The California Flats solar project, in a remote region of southeastern Monterey County known as the Cholame Valley, was approved by the county’s planning commission last month in a unanimous vote, and county supervisors were scheduled to give final approval Tuesday afternoon. Some activists fought the project on grounds that it would endanger protected species including the San Joaquin kit fox, California tiger salamander, California red-legged frog, bald eagle and others.

Construction on the project is expected to begin by the middle of this year and be completed by the end of 2016, with PG&E contracted to receive the remaining 150 megawatts the farm will produce, First Solar announced.

Staff writer Jeremy C. Owens and the Monterey Herald contributed to this report.