Carbon content of different electricity generation methods
A recent poll (BVA for ORANO) produced some surprising results: 69% of French people believe that nuclear power contributes to climate change.
Nuclear power has many drawbacks, but greenhouse gas emissions are certainly not the only reason to reject it.
This largely erroneous perception of the impact of nuclear power on climate change has led us to take stock of the carbon content of each kWh of electricity produced, depending on its mode of production.
This is a complex calculation, since it takes into account emissions during construction of the production facility, those produced during operation and maintenance, and those corresponding to dismantling. Obviously, the calculation involves an assumption about the lifetime of the equipment, and the results vary from one geographical area to another, particularly for solar, wind and biomass. However, by focusing on production, we avoid the endless debate that is obligatory at the level of consumption, on the differences in the energy mix depending on the time of day, the day of year and the season of consumption.
Several organizations, including the IPCC and ADEME, have looked into the matter, and come up with different results (due in particular to different assumptions about equipment lifetimes), but the conclusions are nonetheless very clear: wind, hydro and nuclear power are clearly the best performers in the class, with emissions of the order of 15 to 20g of CO2 per kWh produced, and these emissions are 100% indirect.
Next come photovoltaics and geothermal energy, in a range from 40 to 70g, again 100% indirect.
Biomass is a special case: if we don’t count the CO2 from combustion (since it’s renewable), we find 75 to 200g (equipment and fuel supply chain). Obviously, if we counted the CO2 from combustion, we’d reach emissions levels on the order of those of coal. But burning biomass prevents it from decomposing on the ground, which would generate new greenhouse gas emissions….
Finally, fossil fuels, unsurprisingly, take the cake, with 400 to 500g for natural gas, and 800 to 1000g for coal. It’s important to set the record straight and get everyone thinking about the reality of what’s good or bad for the climate.
JF Vaury