Bill Joy, founder of Sun Microsystems and partner at the venerable venture capital firm Kleiner Perkins Caulfield and Byers, is talking up a handful of companies he's invested in that make use of abundant materials—in some cases materials that get thrown away or burned up—to make valuable commodities and reduce carbon emissions and replace petroleum. He described the new companies today at the Emtech Conference in Cambridge, Massachusetts.

Solidia: The company, based on technology developed at Rutgers, is using carbon dioxide to make building materials that have the strength of concrete, but that rather than emitting one ton of carbon dioxide per ton of concrete, Joy says, it actually uses carbon dioxide as a building material.

Siluria: Natural gas is extremely abundant, but it's not useful for much other than burning it to generate electricity. Unlike oil, it isn't a good building block for drugs and plastics. And unlike oil, it's difficult to ship. To this day, some oil fields burn off the natural gas that comes up the well because there's no economic way to get it to market. Siluria is using directed evolution techniques developed at MIT to quickly sort through large numbers of potential catalysts for breaking down methane and forming building blocks that can be used to make ethylene, an important feedstock material, and eventually a range of chemicals and liquid fuels. The company says it's catalysts work well enough now to make liquid fuels at about $50 a barrel.

Renmatix: Cellulosic materials like wood chips are abundant, but turning them into sugar, which can be used to make ethanol and diesel—is expensive. Renmatix uses water at high temperatures and pressures to break cellulose down. The company says it will be cheaper because it doesn't require the enzymes or expensive catalysts used in current methods.

Aquion: The company is building cheap batteries to store power from wind turbines and solar panels, which could be key to making up for the variability of these electricity sources. The battery uses abundant materials—manganese, salt, water, and carbon—rather than potentially expensive metals like nickel.

Efforts to reduce carbon dioxide emissions in China may be backfiring--at least in the short term.

Next month the country faces a self-imposed deadline to reduce its carbon intensity (a measure of the amount of carbon dioxide emitted per unit of GDP) by 20 percent compared to 2005 levels. In a last minute dash to meet these targets, some local governments have started imposing planned blackouts.

While the blackouts are cutting emissions from power plants, they're having unintended consequences. Factories, which have to keep running to meet production requirements or face fines for missing deadlines, are getting their power instead from backup diesel generators. These emit carbon dioxide and running them has led to a diesel shortage. Thousands of fueling stations have reportedly shut down or refused to sell drivers more than half a tank of diesel fuel. To make up that gap, Chinese refineries are producing more diesel--a strain in a country that has to import most of its oil.

Of course, unintended consequences from efforts to reduce carbon dioxide emissions aren't limited to China. In the United States and Brazil, the use of food crops for biofuels can drive up food prices and lead to the destruction of forests as new land is cleared to make up for lost food production. Clearing that land also results in more carbon dioxide emissions, undoing much of the benefit of biofuels.

Ethanol made from sugar cane rather than corn (the main source of ethanol in the U.S.) results in far less carbon dioxide emissions. But Dan Sperling, director of the Institute for Transportation Studies at the University of California at Davis, estimates that when you figure in the impact of cleared rainforests, that benefit could disappear.

Last year, comprehensive climate and energy legislation was well on its way to becoming law. After a version passed the House, pundits were concerned mostly with whether it would be passed in time for the Copenhagen climate talks last December. But Senators balked, and a drive this summer to put some sort of bill together has stalled.

Yesterday, Senate Majority Leader Harry Reid (D-Nev) threw up his hands, giving up on a comprehensive bill for now in favor of a narrow energy bill without any limit on greenhouse gas emissions or regulations to require renewable energy. What's left are measures to hold BP accountable for the oil spill, to invest in natural gas trucks (the pet project of oil and natural gas tycoon T. Boone Pickens), to improve home energy efficiency, and to restore money to the Land and Water Conservation fund.

Reid says he'll still work on a comprehensive bill, but it looks like it's out of play for the year.