Factors of Sustainability


Environmental, social and governance (ESG) performance has become an increasingly prominent measure of success for corporations. As electricity generation can have a profound impact on the environment, we need to consider factors including:


  • The environmental impact of energy resources
  • The sustainability of energy resources
  • The amount of electricity sent out
  • Waste management

Burning fossil fuels for electricity generation produces large quantities of gaseous emissions:


  • Carbon dioxide (CO2) is the main greenhouse gas. At its current level of concentration in the atmosphere, CO2 has been essential for maintaining the present temperature on Earth, making it habitable.
  • Sulphur dioxide (SO2) is a cause of acid rain. However, it also forms sulphate aerosols in the atmosphere which helps reduce some of the greenhouse effect from carbon dioxide.
  • Nitrogen oxides (NOX) and particulates are health hazards and irritants. Nitrous oxide is also a greenhouse gas.


Emissions that come directly from burning fuels for electricity generation are called direct emissions. They have been increasing in line with economic development and are expected to continue to increase in the future.

World Carbon Dioxide Emissions by Fuel Type Year 2020 Year 2030 Year 2040 Year 2050
Electricity and heat sectors 13,504 5,817 -81 -369
Coal 9,786 2,950 102 70
Oil 629 173 6 6
Natural gas 3,089 2,781 268 128

Source: IEA Net Zero by 2050 Scenario (May 2021)


Emissions of Energy Sources


According to the Climate Change 2021: The Physical Science Basis report of the Intergovernmental Panel on Climate Change (IPCC) concludes that the emissions of greenhouse gases from human activities are responsible for approximately 1.1°C of warming since 1850-1900, and it is estimated that global temperature may reach or exceed 1.5°C of warming over the next 20 years. Energy-related greenhouse gas emissions account for the majority of all anthropogenic emissions which are responsible for over 40% of all energy-related emissions. The impacts of electricity generation go beyond the emission of CO2 and other greenhouse gases. Therefore, stabilising the climate will require cleaner electricity generation, and sustained reductions in greenhouse gas emissions. On a life-cycle basis, nuclear and renewable energy emit far less CO2 than conventional fossil fuel are the most readily decarbonised. 

Average life-cycle CO2 equivalent emissions (source: IPCC)

Environmental Impact and Monitoring


A nuclear power station discharges a small amount of radioactivity during its normal operation. However, the amount is regulated by the state licensing authority and is carefully monitored to ensure a very low, if not insignificant, environmental impact. See more in Performance Monitoring.

Fossil fuel and biomass burning produces considerable quantities of ash and byproducts associated with the sulphur that is present in the fuel. These byproducts are classified as solid waste if they cannot be reused for alternative purposes. In comparison, nuclear power and most forms of renewable energy produce a much smaller quantity of solid matters that are classified as waste. Although the solid waste from nuclear power generation is radioactive, the radioactivity will decrease, albeit very slowly, with time. The handling of this material is discussed in Spent Fuel and Nuclear Waste.


Solid Waste of Energy Sources (IAEA, 2001)

Energy Sources Typical Waste Generation (per QWh)
Coal 36 t ash 36 t Flue Gas Desulphurisation
Oil 1 t ash 36 t Flue Gas Desulphurisation
Gas 29 t gas sweetening waste
Nuclear 0.07 t radioactive waste
Biomass 14 t ash
Solar PV ~0.07 t toxic waste
Hydro/Wind Trace

Source: IAEA information series 01-00678/FS Series 3/01/E