A $100 bill inside a light bulb represents a green business idea
A $100 bill inside a light bulb represents a green business idea - 
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Kai Ryssdal: A year ago today, Congress gave up on its big climate change bill. It's the one that had cap-and-trade in it, an actual market for pollution which could have re-engineered the whole energy economy.

Last week, the House voted on light bulbs. The House GOP wants to block new energy efficiency rules. From the Marketplace Sustainability Desk, Scott Tong has more on what a long strange year it's been in green energy policy.

Scott Tong: A year ago, companies, inventors and investors were planning for the New Math of energy: financial carrots for low-carbon emitters, sticks for fossil fuel producers.

Now, executives come to town and:

Tim Greeff: The term "worthless" has come out a number of times.

Tim Greeff is with the Clean Economy Network. Its members include new energy companies.

Greeff: It's a level of silliness which is similar to having styrofoam cups proactively put back in the cafeteria in the House office buildings. I mean there's moves more out of political spite than any sense of intelligence.

The gridlock has companies undoing big bets. Utility AEP just canceled a $668 million plan to capture carbon dioxide from coal smokestacks. The project assumed government credits -- or money -- for cutting emissions. At least four similar carbon-capture ventures have been canned lately.

Venture capitalist Rob Day at Black Coral Capital says in many cases, federal help doesn't make or break an energy investment. It's more of a tailwind.

Rob Day: It wasn't a determining factor as to whether somebody made an investment or not. But at the same time, it does affect overall momentum and enthusiasm.

For now, business has to make its own case. And in many clean-tech sectors, it does. Investment bank HSBC expects the world's low-carbon market to triple to $2 trillion by 2020.

In Washington, I'm Scott Tong for Marketplace.

Follow Scott Tong at @tongscott