What is the environmental footprint of each energy technology?

We compared the environmental impact of renewable energy and fossil fuel on land use, water use, air pollution and the climate. Renewables came out on top in almost every measure, writes the EEB’s Jonathan Bonadio.

The European Environmental Bureau collaborated with energy experts, industry representatives and NGOs to develop a tool to accompany the assessment of and decision-making around the use of different energy technologies to meet energy demand and shift towards a net-zero emissions energy system.

The ‘Reference Environmental Standards for Energy Techniques‘ project (RESET) is a unique analysis of energy generation technologies, comparing emissions and other negative effects on air, water, soil and climate. It provides an interpretation of the scale of those impacts per unit of energy generated using such metrics as kg of carbon dioxide (CO2) per megawatt-hour (MWh) of electricity generated.

This provides decision-makers with a powerful tool to help them select the best available technologies to fuel the transition to a carbon-neutral society and to minimise and mitigate the impact of the selected options.

Land and water

The assessment covers a plethora of major environmental impacts occurring during the full life cycle of the energy projects – from extraction to recycling or landfilling. As such, the project allows for a consideration of impacts beyond the operational phase, highlighting the reality that every generation technology comes at a cost to the environment.

When it comes to land use, rooftop solar photovoltaics and geothermal energy are the least space-hungry technologies. However, a simulation carried out in the context of the LOCOMOTION project, in which the EEB is also involved, revealed that, outside of urban areas, the land use requirements for solar installations would expand as our energy system’s dependence on the sun grew. This will require careful planning to avoid any unintended damage to nature and biodiversity.

When integrating the need for mining, however, lignite has medium-scale impact on land use, in addition to being a major polluter of land and water. Bioenergy with dedicated crops have among the highest impacts on land use, only exceeded by hydropower dams.

When it comes to water use, renewables such as solar photovoltaics, biogas and wind have the lowest impact, while technologies involving combustion, such as coal, fossil gas and solid biomass show medium to high impacts. Hydropower shows the highest impact, despite significant site-specific variations.

Air and climate

The picture is more complex when considering air pollution. Coal and solid biomass are among the worst polluters. However, some renewable technologies can involve substantial emissions, namely during their production processes. On certain pollutants, such as SOx, biogas from energy crops can also show high emissions.

On climate, the picture is clearer: renewables almost always rank better than fossil fuels, sometimes with 100 times lower emissions and occasionally even negative emissions. This remains true when including the whole life cycle assessment of technologies. For renewables, the greatest impacts occur during the extraction and construction phases but progress can be made through efficiency gains and a clean local energy mix during construction. Fossil fuels, on the other hand, emit during their entire lifecycle and, thus, do not meet the environmental requirements of our future energy system.

Following the recent publication of the 6th IPCC Report (AR6) and in the context of the climate emergency that threatens all areas of the environment, our research sends a clear message to policymakers: they must renew their commitment to renewable energy and accelerate the deployment of these climate-saving technologies.