Climate & Energy

Umbra on carbon trading

Dear Umbra, I don’t understand carbon credits and how people can buy/sell/trade them. How is this good for our environment? Elizabeth Columbus, Ohio Dearest Elizabeth, …

Power from rooftops could replace coal

More than half of today’s electricity, more than 16 percent of today’s energy

Enough sunlight strikes unshaded U.S. rooftops to replace all the coal and some of the natural gas we use to make electricity. Backup via ground source heat pumps, and smart grid technology would allow this variable energy source to displace base-load coal with today's technology. Whether this is the most cost effective way to displace coal is another question. Also rooftop solar is a silver BB rather than a silver bullet: Even after massive efficiency improvements we will need to get many times the power from non-rooftop sources than from rooftops. According to a 2003 study by the Energy Foundation (PDF), solar PV that converts 15 percent of sunlight to electricity could produce 710,000 Megawatts on rooftops that will be available in 2050. Doug Wood thinks that with concentrating PV using advanced aerospace quality cells we could convert solar at 30 percent rather than 15 percent efficiency. Scaling back to rooftops available today (using 2003 numbers from the same study and extrapolating forward) we could produce around 1.05 billion megawatts today. We normally assume 22 percent capacity factor (PDF) for PV. So that would give us about 2.3 billion megawatt hours, or around 56 percent of today's electrical production -- more than coal provides. Further, waste heat from this process could provide much of our heating and cooling needs as well. The EF study I cited suggests that about 65 percent of commercial roof space is unshaded compared to about 22 percent of residential roof space. Since some commercial scale chillers run on low to medium temp heat today, with enough storage solar CHP could provide close to 100 percent of commercial heating and cooling. But that much storage takes a lot of capital for a small incremental gain. So more realistically, we would put 16 to 24 hours of low temp Phase Change Material storage and use ground source heat pumps to provide the other 15 percent of low temp needs. As a side effect, the overnight storage would let us run those heat pumps when the electricity was cheapest -- which will prove more important than it might appear at first glance.

Don't take it for Granite

N.H.’s Shaheen puts energy issues at center of her campaign for Senate

In New Hampshire, former Gov. Jeanne Shaheen (D) is challenging incumbent John Sununu (R) for his U.S. Senate seat, and she’s making energy concerns a …

The sequestration pony

Nice critique of carbon sequestration at Low Tech Magazine.

Per Hirsh incentives

Newsweek political journalist transcribes McCain campaign spin on energy

Last October, Barack Obama laid out a detailed, ambitious, and comprehensive energy plan, and he’s been talking about it ever since. A couple weeks ago, …

Is that a pig in the sky?

Republican Congressional candidate says main priority is energy reform

While Oregon Sen. Gordon Smith (R.) tries to fuzz his ties to the GOP and his unswerving devotion to the Bush agenda (in between lurches to the center around election time), at least Oregon voters in the First District have a choice that's actually interesting: either Democrat David Wu, considered a huge disappointment and one of the least effective members of Congress (he's so lame that even the Oregonian, who typically only stops endorsing incumbents after they've been six feet under for months, endorsed his primary opponent) or this guy. I don't know if that guy's got any of the right answers, but he's sure got the right questions.

Hill heap

A weekly roundup of greenish news from the Capitol

Some political news debris from this week: • The League of Conservation Voters announced today that they’ve created the first green bundling site. This allows …

What drove the dramatic retreat of arctic sea ice during summer 2007?

Funny you should ask. That is the title of an analysis published this month in Geophysical Research Letters ($ub. req'd) by four scientists from the Polar Science Center, Applied Physics Laboratory, College of Ocean and Fishery Sciences, University of Washington, Seattle. What did they conclude?

Reps. for renewables

New bill to support renewables offered in House

Reps. Jay Inslee (D-Wash.), Bill Delahunt (D-Mass.), Jim McDermott (D-Wash.), and Mike Honda (D-Calif.) introduced legislation [PDF] yesterday to provide security for investments in the …