Building solar, wind or nuclear plants creates an insignificant carbon footprint compared with savings from avoiding fossil fuels, a new study suggests.
The research, published in Nature Energy, measures the full lifecycle greenhouse gas emissions of a range of sources of electricity out to 2050.
It shows that the carbon footprint of solar, wind and nuclear power are many times lower than coal or gas with carbon capture and storage (CCS). This remains true after accounting for emissions during manufacture, construction and fuel supply.
“There was a concern that it is a lot harder than suggested by energy scenario models to achieve climate targets, because of the energy required to produce wind turbines and solar panels and associated emissions,” explains project leader Dr Gunnar Luderer, who is an energy system analyst at the Potsdam Institute for Climate Impacts Research (PIK).
Luderer tells Carbon Brief: “The most important finding [of our research] was that the expansion of wind and solar power…comes with life-cycle emissions that are much smaller than the remaining emissions from existing fossil power plants, before they can finally be decommissioned.”
Carbon debt
Critics sometimes argue that nuclear, wind or solar power have a hidden carbon footprint, due to their manufacture and construction. This large “carbon debt”, and the related debt of energy, must be paid off if they are to cut emissions over their lifetime.
Factories churning out solar panels use large amounts of electricity, often sourced from coal-fired power stations in China. Wind turbines and nuclear plants need a lot of steel and concrete. And the centrifuges that separate nuclear fuel also rack up a big electricity bill.
Yet zero-carbon sources of electricity are not the only ones to have a hidden, indirect carbon and energy footprint.
For coal and gas, these lifecycle energy uses and emissions come from extraction machinery and fuel transport. Significantly, they also come from methane leaks at pipelines, well heads or coal mines. These lifecycle emissions continue, even if coal or gas plants add CCS, which also may not capture 100% of emissions at the power plant.
What’s more, the indirect energy uses and emissions of each technology will shift over time, due to changing fuel sources, advances in manufacturing and the evolution of global electricity supplies.
The new research, from lead author Michaja Pehl and colleagues, comprehensively measures the lifecycle energy use and greenhouse gas emissions of different sources of electricity, between now and 2050.
It then compares these hidden footprints in a world that cuts emissions in line with a 2C climate goal and a world that stops further climate action.
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