Does Renewable Energy have a hidden carbon footprint?

The mandate of renewable energy is to deliver clean energy to the appropriate grid network in order to reduce carbon emissions and help create a cleaner more sustainable environment for all. It cannot be disputed that with no fossil fuel to burn the renewable energy production process reduces emissions substantially in some cases close to zero.

However the generation process is not the whole story and there has always been voices of distraction pointing towards the manufacturing and distribution of the technology and its components. The detractors claim that these processes contain a hidden carbon footprint with the emissions they create pushing the projects over the course of their lifespan into a negative carbon debt position.

For example the factories that manufacture solar panels use vast amounts of electricity, much of it likely to be generated from carbon heavy sources. Wind turbine installations require a sizeable amount of steel and concrete and the transport costs of moving the core elements of any renewable energy project to its final location usually involves long distances and therefore carbon heavy transport issues.

New research however published in Nature Energy and carried out by Carbon Brief shows that the carbon footprints of renewable energy technologies including wind turbines and solar panels are vastly less than coal or gas generation including those with carbon capture and storage. In addition the carbon footprint of the renewable energy installations remained below that of coal and gas when manufacture, transport, and construction were included.

Dr. Gunnar Luderer energy system analyst at the Potsdam Institute for Climate Impacts Research (PIK) and study co-author said: “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.”

He went on to tell 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.”

The first stage of the research was to work out the energy required to build power stations and provide the fuel in order to generate electricity. The study found that fossil fuel plants require “significantly higher” amounts of energy for this process than wind and solar power.

The study found for example that 11% of energy generated by a coal fired power station is offset by the energy required to build and supply the plant. Wind and solar in comparison need only 2% of energy generated to offset build and supply requirements.

Study co-author Edgar Hertwich – Professor of Industrial Sustainability at the Yale School of Forestry and Environmental Studies – told Carbon Brief “I continue to be amazed just how low the embodied energy use of solar, wind and nuclear power is, in comparison with others.”

With the research stating that the footprint of wind and solar is much less than coal and gas generation Dr Luderer told Carbon Brief “A crucial strength of our approach is that it fully accounts for future changes in the energy system. For example, increasingly less energy will be required to produce solar modules, due to technological progress and a shift towards less energy-intensive technology variants. At the same time, the global climate change mitigation effort will reduce the CO2 emissions per unit of electricity and steel inputs, further limiting life-cycle greenhouse gas emissions. The earlier studies considered by the IPCC did not account for these future changes, thus overestimating indirect energy requirements and indirect greenhouse gas emissions of several low-carbon technologies.”

The footprint of solar comes in at 6gCO2e/kWh and wind is also 4gCO2e/kWh. In contrast, coal CCS (109g) and gas CCS (78g) have relatively high emissions, compared to a global average target for a 2C world of 15gCO2e/kWh in 2050.

The study therefore concludes that contrary to the claims of critics the hidden emissions due to building wind turbines, solar panels or nuclear plants are very low, in comparison with the savings from avoiding fossil fuels.

“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,” Dr Luderer concluded.

Reference: Information and quotes written here relating to the study mentioned above along with full details of the study and its findings can be accessed at

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