Oil is the bloodstream of the global economy, but its time as the dominant source of energy, powering everything from our cars and trucks to our pharmaceuticals and farming practices, is coming to an end.

At least, that's the upshot of a lot of the talk this week by Washington state CEOs, venture capitalists, scientists and university leaders who attended the Technology Summit in Bellevue. The summit was sponsored by the Washington Technology Center, an economic development agency.

Here's the problem they talked about: Carbon dioxide emissions (carbon dioxide is a greenhouse gas that is dangerous when inhaled in high concentrations) are increasing in the U.S. while the domestically produced content of our energy portfolio is decreasing.

U.S. carbon emissions from the consumption of oil increased 21 percent from 1990 to 2005, and 98 percent of our carbon emissions come from the burning of fossil fuels, like oil and coal, which are non-renewable sources of energy.

Meanwhile, the U.S. imports nearly 60 percent of its oil, up from 46 percent in 1996. And rapidly developing nations such as India and China also are increasingly reliant on imports and competing for supplies in a global market.

In other words, if we want to breathe clean air and leave a decent planet to our children, and do business and make money, and keep the lights on in our houses and wean ourselves off oil and extricate ourselves from questionable entanglements with foreign markets and governments, we're going to have to come up with a more diversified portfolio of energy sources, including renewable sources. We're going to need to domestically produce more energy, conserve more and, I would add, grow smarter in our approach to land-use and transportation, by which I mean we need to invest in more mass transit and encourage other ways of getting to and from work to reduce the vehicle miles we travel which are rising and further increasing our carbon emissions.

Because the air isn't getting any cleaner, as Douglas Lemon, director of laboratory strategy for the Pacific Northwest National Laboratory, implied when he spoke during the summit. China is building the equivalent of "two coal-fired power plants per week," he said. "We share the same atmosphere as they do." Lemon said the U.S. needs to engage China in reducing both countries' carbon footprints.

Because oil is neither becoming cheaper nor more plentiful, as Boone Pickens, the billionaire energy investor, said in a speech at Georgetown University reported by Bloomberg News. Pickens said he though oil was approaching $125 a barrel and will eventually reach $150 per barrel. "I won't be investing in $150 oil." And, he added, world oil supplies won't exceed 85 million barrels a day because of high depletion rates of existing wells. "There is only 85 million barrels of oil globally in the market coming a day, and I don't think you can increase that 85 million."

And because it's good for business and good for the environment, as Kirt Montague, CEO of Prometheus Energy Company, told his audience in Bellevue. Prometheus, a Seattle startup, is aimed at transforming waste gases at landfills, coal mines and dairy farms into liquid natural gas as an alternative way of powering cars and trucks.

In 2006, the company attracted $20.2 million in equity financing and a $25 million line of credit to pursue its project. And it is publicly listed on the Alternative Investment Market of the London Stock Exchange. The company has begun producing liquefied natural gas from the world's first landfill gas-to-LNG plant. The plant was installed in late 2006 at the Frank R. Bowerman Landfill in Orange County, Calif. The entire output of the plant will be used as an alternative fuel in mass transit vehicles in the Orange County Transit Authority Fleet. The current gas-to-LNG plant, which has the production capacity of 5,000 gallons per day, is the first of three phases planned to be built at the landfill.

"There's plenty of room in this space for a number of parties to play in," Montague said, noting that the market for what Prometheus does is large.

The speakers at the summit in Bellevue also touted the potential of biomass, tidal power and other alternative forms of energy to reach the goals of weaning the U.S., not to mention Washington state, off foreign oil, to curb greenhouse gas emissions and to do business in a cleaner and possibly even more profitable way.

There was a recurring theme, though: There is no silver bullet in the pursuit of these goals. Each technology or suggested alternative form of energy is only a part of the potential solution. The state and the country need a diverse portfolio of energy sources. We also need to conserve more by living smarter, better and by consuming less. As Jack Baker, vice president of energy/business services for Energy Northwest, put it: "We have to fundamentally change lots of stuff."