Renewable energy systems return more net energy to society than fossil fuels

New research shows that, despite previous beliefs, renewable energy systems have a higher ‘energy return on investment’ than fossil fuels.

Dr Emmanuel Aramendia in the School of Earth and Environment (SEE) and the Sustainability Research Institute (SRI) led the research. 

He was joined by co-authors Dr Paul Brockway and Dr Jonathan Norman (both SEE), Professor Peter Taylor (SEE and School of Chemical and Process Engineering), Dr Zeke Marshall (UK Centre for Ecology & Hydrology) and Professor Matthew Heun (Calvin University). 

The research paper, published in Nature Energy, argues that a different way of measuring energy shows that renewable energy is more efficient than fossil fuels.

Expanding net energy analysis 

Net energy refers to the energy available to society after the energy requirements of the energy system are used. 

Previously, researchers have analysed the net energy implications of the energy transition at the ‘final energy stage.’ In this study, the researchers expand the analysis to measure energy delivered to society at the 'useful energy stage’. 

The final and useful stages are points in the energy conversion chain, which describes the process of getting energy from the environment to its applications in society.

  • The ‘final stage’ of energy refers to energy bought by consumers, such as electricity and fuel.
  • The ‘useful stage’ of energy is what is produced by that electricity or fuel, such as light (from lightbulbs) or movement (of a vehicle). 

Including the useful stage means that the study accounts for the efficiency of energy delivery systems between electricity and lighting, or fuel and driving.

Energy Return on Investment

The researchers estimated fossil fuels’ Energy Return on Investment (EROI)—the ratio of energy delivered, divided by the energy requirements of the system—at the ‘useful stage’ over 50 years. 

They found that the ratio for fossil fuels was considerably lower at the ‘useful stage’ than at the ‘final stage’. This is due to high inefficiencies in the conversion of fossil fuel final energy into useful energy. 

Using published figures for renewable energy systems, they also found that the renewable EROI for solar and wind power is higher than that of fossil fuels. 

Their results contradict the view that renewable energy systems can’t replace fossil fuels without society losing energy. 

Investing in renewable energy systems is beneficial for society

Emmanuel Aramendia said: “Our findings contradict the conventional view that a transition to renewable energy systems will reduce the amount of energy available to society.

“Instead, we show that investing the energy we are producing now into renewable energy systems will ultimately provide more energy to society than investing the same amount in fossil fuels.

“Not only do renewable energy technologies have better environmental credentials than fossil fuels but they also outperform fossil fuels.” 

Investing in renewable energy systems is not only essential for climate change mitigation but is also beneficial to meet society’s energy demand. 

Across the world, the demand for energy is growing, particularly in developing countries. 

The authors argue that renewable energy has the strongest potential to meet this soaring demand. 

They encourage governments to set ambitious renewable energy targets instead of rolling back commitments. 

Maintaining the status quo of dependency on fossil fuels is detrimental for populations in terms of climate change, extreme weather, food insecurity and, as this study shows, energy availability. 

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