Renewable energy and climate

Renewable energy sources have undoubtedly come to the fore in recent years in part because their impact on climate change is lower than that of thermal power plants. Although these sources, which often do not release greenhouse gases into the atmosphere when generating energy, are therefore described as “zero-emission,” more comprehensive comparisons are needed. Calculations that consider the entire process from a power plant’s construction to its decommissioning (life cycle) allow for a more accurate comparison. For example, a wind turbine does not emit greenhouse gases while generating electricity; however, fossil fuels are often used in producing the materials used to manufacture the turbine, and the emissions arising during this process also need to be taken into account. This is also true for nuclear power plants—whose construction uses substantial amounts of iron, steel, and concrete—and for coal-fired power plants, where energy is consumed during coal mining. The table below, using a life-cycle approach, shows the amount of CO2e (carbon dioxide equivalent) greenhouse-gas emissions released into the atmosphere per 1 kWh of electricity generated.

Greenhouse-gas emissions by energy source in electricity generation

Different figures can appear across studies reporting emission data for power plants, and the specific characteristics of the plants sampled can be misleading. The study used in the table above contains the average figures from 103 different pieces of research. It is also possible to find studies indicating that solar photovoltaic and nuclear power plants emit more than 200 grams of greenhouse gases per 1 kWh of electricity produced.