Transition to low-carbon energy leads to decline in available energy

In order to maintain the current level of available energy in 2050, renewable energy sources will have to grow two to three times faster than previously estimated.

05/09/2018 | 2:00 PM

This is the conclusion of VU professor of environmental economics Jeroen van den Bergh, together with his colleague Lewis C. King from the Universitat Autònoma de Barcelona, in a recent publication in Nature Energy. They also propose a new indicator with which we can better monitor what an energy source contributes to CO2 output and can allocate the remaining available CO2 as efficiently as possible.

In order to limit the potential climate change to a maximum of two degrees by 2050, there is currently substantial growth in the use of renewable energy sources, such as windmills and solar panels. In Nature Energy, Van den Bergh and King state that the low net yield of such energy sources is not fully taken into account. The higher investment in the production of wind turbines or solar panels means a greater loss between gross and net energy than with fossil fuels. “You have to deduct the investment from the energy efficiency of a windmill or solar panel. This means that the net energy yield will therefore be reduced”, says Van den Bergh.

Decline in net energy
By correcting the energy from gross to net, the authors show that a low carbon transition is likely to lead to a decline in available net energy per capita of 24 to 31% by 2050. This means a strong turnaround compared to the trend of steadily increasing by 0.5% per year in the recent past. “We will have to either adjust our current energy-guzzling lifestyles or realise a much faster growth in renewable energy, unless we achieve unprecedented efficiency savings on the user end in the coming decades, which is unlikely.”

Remaining CO2 budget
In order to maximize the net energy from the remaining CO2 budget, Van den Bergh and King propose a new indicator: ‘Energy return on carbon’ (EROC). This reflects the net energy of fossil fuels per ton of CO2 output. On this basis, we can better monitor how each energy source contributes to the energy supply while producing minimum CO2 emissions. A high EROC means that producing each unit of energy has led to relatively low CO2 emissions. Van den Bergh: “Natural gas combined with the capture and underground storage of the emitted CO2 yields the highest EROC of all fossil fuels.”