Published on December 15th, 2017 | by Joshua S Hill0
Transition To Wind & Solar Would Result In Small Indirect Greenhouse Gas Emissions
December 15th, 2017 by Joshua S Hill
A new study has found that wind and solar indirect lifecycle emissions are not only on the lower scale compared to other generation technologies, but would result in only minor indirect greenhouse gas emissions if a full decarbonization of the global electricity sector was achieved with these technologies.
Many critics of renewable energy technologies such as wind and solar like to cast doubt on the overall impact of these technologies on the environment when the entire lifecycle is taken into account — from resources to construction to deconstruction. It is always worthwhile to acknowledge these possibilities, because the materials used to construct a wind turbine and the effort used to extract those materials have their own emissions, as does the construction process. Finally, what impact will the waste of these technologies have once their lifespans are up and they need to be destroyed or recycled?
However, according to a new comprehensive study published this month by the Potsdam Institute for Climate Impact Research and published in the journal Nature Energy that analyzed the lifecycle of various energy generation technologies, wind and solar have a favorably low-greenhouse gas emissions level from their complete lifecycles, but that a full decarbonization of the global electricity sector using wind and solar technologies would “induce only modest indirect greenhouse gas emissions — and hence not impede the transformation towards a climate-friendly power system.”
Specifically, according to the article, “We find that cumulative emissions attributable to upscaling low-carbon power other than hydropower are small compared with direct sectoral fossil fuel emissions and the total carbon budget.”
“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,” explained lead author Michaja Pehl. “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 importance of this research is that it brings together two separate research branches for the first time. The researchers provided an analysis of embodied energy use and indirect greenhouse gas emissions from all relevant electricity sector technologies. But for the first time the researchers combined simulations based on integrated energy-economy-climate models that estimate cost-optimal long-term strategies to meet climate targets with life cycle assessment approaches.
Their results are good news for supporters of renewable energy technologies, and opponents of coal — even coal equipped with carbon capture and storage (CCS). Specifically, fossil fuel powered plants equipped with CCS account for life-cycle emissions of approximately 100 grams of CO2-equivalents per kWh of electricity produced. This is ten times more than the approximate 10 grams of CO2-equivalents for wind and solar power they project for 2050 based on a climate protection scenario 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,” said Gunnar Luderer, energy system analyst from PIK and project leader.
“Capturing CO2 from coal plants can reduce emissions per kWh by around 90 percent, but substantial life-cycle greenhouse gas emissions remain. 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.”
“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 added.
“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. The faster the low-carbon transformation of power supply is accomplished, the lower is the overall remaining carbon burden for the climate.”
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