by Susan DeFreitas

Making the switch from gas-powered cars to electric vehicles and increased energy efficiency in buildings have both been lauded as important steps in cutting carbon emissions. But some big brains at the University of California at Berkeley have run the numbers and studied the scenarios, and, according to the results of a recent study, the least expensive way for the Western U.S. to reduce greenhouse gas emissions enough to help prevent the worst consequences of global warming is to replace coal with renewables and other sources of energy.

The study, published in the April issue of the journal Energy Policy, highlights an analysis using Switch, a highly detailed computer model of the electric power grid, to study generation, transmission and storage options for the states west of the Kansas.

Using this model, researchers arrived at a pretty simple conclusion: ”Decarbonization of the electric power sector is critical to achieving greenhouse gas reductions that are needed for a sustainable future,” said Daniel Kammen, the Distinguished Professor of Energy in UC Berkeley’s Energy and Resources Group and lead author on the study. ”To meet these carbon goals, coal has to go away from the region.”

Sure, but how do we do that, exactly?

Here’s how: The Berkeley researchers said policy changes are needed to cap or tax carbon emissions to provide an incentive to move toward low-carbon electricity sources. And while some previous studies have emphasized the high cost of such taxes or caps, this new study shows that replacing coal with more gas generation, as well as renewable sources like wind, solar and geothermal energy, would result in only a moderate increase to consumers in the cost of electric power – at most, 20 percent.

Why? The study’s authors estimate a lower ratepayer cost behind the switch based on the expected evolution of the electrical grid over the next 20 years—with coordinated construction of new power plants and transmission lines—which would substantially reduce the actual consumer cost of meeting carbon emission targets. Meaning, basically, if we’re going to rebuild the grid anyway, we have a built-in opportunity to redesign that grid.

“While the carbon price required to induce these deep carbon emission reductions is high—between $59 and $87 per ton of CO2 emitted—the cost of power is predicted to increase by at most 20 percent, because the electricity system will redesign itself around a price or cap on carbon emissions,” said Kammen. And, in perhaps the understatement of the year, he added: “That is a modest cost considering that the future of the planet is at stake.”

While the study does emphasize the integration of renewables, it also relies on new gas generation, and leaves the door open to nuclear generation as well.