It should be a give that technologies like wind and solar power are better for the environment and global emissions than fossil fuel power like coal. Yet there are those who argue the energy put into making wind and solar power generating technologies make their life-cycle emissions higher than other energy technologies. Now, a new international study published in the journal Nature Energy is the latest in a growing body of evidence to dispel the outdated idea.
The study led by the Potsdam Institute of Climate Impact Research found that even fossil fuel-based power plants with carbon capture sequestration (CCS) like coal, biomass and gas, will produce life-cycle emissions of around 100 grams of carbon dioxide (CO2) per kilowatt hour (kWh) of electricity produced. That’s 10 times more than the roughly 10 grams of CO2 per kWh that could be attributed to the life-cycle emissions from wind and solar power. That’s in a scenario they project for 2050 in which power production is almost completely decarbonized.
“There is no such thing as truly clean coal. Conventional coal power currently comes with around 1000 grams of CO2-equivalents per kWh. Capturing CO2 from coal plants can reduce emissions per kWh by around 90 percent, but substantial life-cycle greenhouse gas emissions remain,” says Gunnar Luderer, energy system analyst from Potsdam and project leader. “To keep global warming below 2°C, however, virtually carbon free electricity is necessary. This makes it increasingly implausible that coal power will play a major role in the future, even if equipped with CO2 scrubbers.”
The study combined life cycle assessment approaches and energy-economy-climate simulation models that estimate long-term strategies to meet climate targets. Previously, the two were considered separately, according to Potsdam.
“Both fossil and non-fossil power technologies still come with a certain amount of greenhouse gas emissions within their life cycle—on the one hand because it needs energy to construct and operate them, on the other hand because of methane emissions, e.g. from coal and gas production,” said lead author Michaja Pehl of Potsdam. “However, we found there are substantial differences across technologies regarding their greenhouse gas balance. Electricity production from biomass, coal, gas and hydropower for instance induces much higher indirect greenhouse gas emissions than nuclear electricity, or wind and solar-based power supply.”
The study also found that scaling up wind and solar would only create modest, indirect greenhouse gas emissions. “When it comes to life cycle greenhouse gas emissions, wind and solar energy provide a much better greenhouse gas balance than fossil-based low carbon technologies, because they do not require additional energy for the production and transport of fuels, and the technologies themselves can be produced to a large extend with decarbonized electricity,” said Edgar Hertwich, a Yale University industrial ecologist and study co-author.
As more wind and solar power come online and the technology continues to innovate, their emissions impacts will also be reduced as less energy will be needed to make them.
“Some critics have argued renewable energies could come with high hidden greenhouse gas emissions that would negate their benefits to the climate. Our study now shows that the opposite is true,” Luderer stated. “During the transition to clean power supply, the additional life-cycle emissions for building up wind and solar capacities are much smaller than the remaining emissions from existing fossil power plants before they can finally be decommissioned.”Tweet