WASHINGTON — Recognizing that high-speed Internet has joined telephone service and electricity as essential tools of modern life, the federal government will unveil an ambitious blueprint this week to extend broadband to virtually all Americans.

Crafted by the Federal Communications Commission over the past year, the national broadband plan is expected to set the federal government’s high-tech agenda on a variety of fronts, with far-reaching implications for Silicon Valley. At its core, the plan, which will be released Tuesday, will propose ways to close the long-standing digital divide by bringing broadband into 90 percent of American homes by 2020.

For those with broadband already, the plan will target vastly increased speeds for wired and wireless service, fostering the already-booming market for Web-based video and other high-bandwidth applications. FCC Chairman Julius Genachowski said the plan could spur advancements in telemedicine, education and energy efficiency through a Web-enabled smart grid.

“World-class broadband,” Genachowski said in a speech last month, “is our generation’s great infrastructure challenge.”

The FCC says that about 93 million Americans, almost a third of the population, currently lack high-speed Internet at home — a huge untapped market for high-tech firms that advocates say a national broadband initiative could help them reach.

In the case of Google, for example, universal broadband would mean more Web ad clicks, smoother YouTube video quality, and easier collaboration on Google Docs and other sharing applications, an executive said.

“The more people on the Internet, the better our business model works,” said Vint Cerf, a founding father of the Internet who now serves as “chief Internet evangelist” for Google. “And high-speed creates a lot of opportunities for collaboration.”

Cisco Systems, meanwhile, stands to sell more routing equipment to direct the Web traffic of millions more users. But the importance of broadband extends far beyond any one company, said Jeffrey Campbell, Cisco’s senior director of technology and trade policy.

“This is highly relevant to the valley and the tech industry in general,” Campbell said. “If the United States is going to continue leading the world in creating applications for the Internet, we need to make sure people have access and we need world-class speeds.”

The country is lagging on both fronts now. Studies show the United States trailing a dozen or more countries in the proportion of people who have broadband and in the speed of service. While some critics question the criteria for those rankings, “few would suggest we are leading the world in broadband, or are even as close as we should be,” Genachowski said.

The plan will focus simultaneously on expanding access and increasing speeds. According to several recent surveys, about one-third of households lack broadband connections at home, and they are concentrated in low-income and rural communities. All but about 4 percent of households have access to at least one broadband service. The most oft-cited reasons cited for not signing up are that people don’t see the need or can’t afford the typical $40 to $45 a month fee.

FCC officials in recent weeks have floated a number of ideas to close the access gap that are expected to be included in the plan:

Redirecting a roughly $8 billion-a-year government program that subsidizes telephone service for rural and low-income communities toward expanding high-speed Internet in underserved areas.

Setting aside a slice of the radio spectrum for free or low-cost wireless service.