What’s better than a zero-carbon source of electricity like solar or wind? One that removes carbon from the atmosphere—a negative-carbon source.
It’s entirely possible, too. By combining two existing, though still not entirely proven, technologies, researchers have devised a strategy that would allow much of western North America to go carbon negative by 2050. In just a few short decades, we could scrub carbon dioxide from the air and reverse the emissions trend that’s causing climate change.
The trick involves pairing power plants that burn biomass with carbon capture and sequestration equipment, also known as CCS. While politicians and engineers in the U.S. have been trying—unsuccessfully—to build commercial-scale, coal-fired CCS power plants for more than a decade, the technology is well understood. Originally envisioned as a way to keep dirty coal plants in operation, CCS may be even better suited for biomass power plants, which burn plant material, essentially turning them into carbon dioxide scrubbers that also happen to produce useful amounts of electricity.
The power plants would take excess biomass, burn it just as they would coal, and then concentrate and inject the emitted carbon dioxide deep into the earth where it would be remain sequestered for generations, if not millennia. (Technically, its the plants in this scenario that are scrubbing carbon from the atmosphere, but the CCS equipment ensures it doesn’t return.)
John Timmer, writing for Ars Technica:
The authors estimate that it would be economically viable to put up to 10GW of biomass powered plants onto the grid, depending on the level of emissions limits; that corresponds to a bit under 10 percent of the expected 2050 demand for electricity. The generating plants would be supplied with roughly 2,000 PetaJoules of energy in the form of biomass, primarily from waste and residue from agriculture, supplemented by municipal and forestry waste. In all low-emissions scenarios, over 90 percent of the available biomass supply ended up being used for electricity generation.
Dedicated bioenergy crops are more expensive than simply capturing current waste, and they therefore account for only about seven percent of the biomass used, which helpfully ensures that the transition to biomass would come with minimal land-use changes.
The tidy proposal suggests that we could add these power plants to actively remove carbon from the atmosphere while, as Timmer points out, still allowing us to use fossil fuels like natural gas to help stabilize the grid. In fact, the biomass plants equipped with CCS could begin their lives burning coal while the market for biomass waste collection and distribution develops, smoothing the transition.
There’s still the matter of shifting the current system, which favors fossil fuels, over to this more diverse mix. But it’s a sign that, with the right investments, we could achieve some very audacious reductions in carbon dioxide emissions in a very short time.
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