Big transmission lines and global climate change

The environmental review document for the proposed "Sunrise Powerlink" transmission line contains a big surprise about global climate change. Call it the "Sunrise Surprise."

"[T]he Proposed Project would cause an overall net increase in GHG [greenhouse gas] emissions and a significant climate change impact." (ES-25)

Why is this a surprise? Because SDG&E says it wants the line, in part, to get renewable energy to San Diego, and the California Public Utilities Commission appears to have taken SDG&E at its word in the environmental review document.

But even accounting for reduced emissions from use of renewable energy, the document says that reduction in greenhouse gas emissions would be outweighed by other aspects of the project. Project construction and the escape of sulfur hexaflouride, a very potent greenhouse gas, from electrical transmission equipment over the life of the transmission line would result in significant greenhouse gas emissions. In other words, the line would contribute to global climate change instead of improving it.

Just looking at that last paragraph, much less writing it, makes my head hurt. But it has important implications.

Many people assume that we can reduce U.S. greenhouse gas emissions--and thus slow down global climate change--by building giant renewable energy facilities far from urban population centers and then sending the electricity to the cities via high-voltage transmission lines. But what if that assumption is wrong?

Obviously, one environmental review document doesn't mean all high-voltage transmission lines will increase greenhouse gas emissions. But it does mean that global climate change impacts need to be studied carefully when high-voltage transmission lines are proposed. We now know we can't just assume they will help.

With luck, we will see a similar environmental review done in Minnesota this year, for the 600 miles of proposed transmission lines for the proposed CAP X 2020 project. These lines are much longer than the 150 miles of the proposed Powerlink, but 345 kV instead of the Powerlink's proposed 500 kV/230 kV mix.

The North Star chapter of the Sierra Club asked for this global climate change modeling in its CAP X 2020 comments to the Department of Commerce earlier this month. (See pages 4-6 here.)

One more thing about the "Sunrise Surprise": it doesn't mean we can't have renewable energy. But it does suggest that if we are serious about using renewable energy to do something about global climate change, we need to consider putting renewable energy generating facilities closer to the places that will use the power. Examples are community-owned wind turbines and solar panels on rooftops. Typically those renewable energy solutions don't require such large transmission lines, with their big construction impacts.

Photo: 500 kV transmission line near Ocotillo, CA. The ground disturbance is from off-road vehicles being ridden cross country rather than on the transmission line's access roads.