[Micele]

Studie vergelijkt fossiel met hernieuwbare energie en komt tot nieuwe resultaten.

https://www.nature.com/articles/s41560-019-0425-z

Analysis | Published: 11 July 2019

Estimation of global final-stage energy-return-on-investment for fossil fuels with comparison to renewable energy sources

Paul E. Brockway, Anne Owen, Lina I. Brand-Correa & Lukas Hardt

Abstract

Under many scenarios, fossil fuels are projected to remain the dominant energy source until at least 2050.

However, harder-to-reach fossil fuels require more energy to extract and, hence, are coming at an increasing ‘energy cost’.

Associated declines in fossil fuel energy-return-on-investment ratios at first appear of little concern, given that published estimates for oil, coal and gas are typically above 25:1.

However, such ratios are measured at the primary energy stage and should instead be estimated at the final stage where energy enters the economy (for example, electricity and petrol). Here, we calculate global time series (1995–2011) energy-return-on-investment ratios for fossil fuels at both primary and final energy stages.

We concur with common primary-stage estimates (~30:1), but find very low ratios at the final stage: around 6:1 and declining.

This implies that fossil fuel energy-return-on-investment ratios may be much closer to those of renewables than previously expected and that they could decline precipitously in the near future.

ook via:

https://electrek.co/2019/07/17/egeb-fossil-fuel-eroi/

A new study in Nature Energy takes a closer look at the energy return on investment (EROI) for fossil fuels and finds they’re not nearly as efficient as they’re made out to be, once all factors are considered.

While most believe the EROI of fossil fuels to be around 25:1, hovering far above renewables, fossil fuels are becoming harder to reach and are requiring more energy to extract, the study claims. Once that “final stage” EROI is considered, oil, coal, and gas have an EROI around 6:1. As the abstract notes:

This implies that fossil fuel energy-return-on-investment ratios may be much closer to those of renewables than previously expected and that they could decline precipitously in the near future.

As fossil fuels become even harder to reach, those numbers will drop further, as study co-author Paul Brockway told Bloomberg. “The transition from fossil fuels to renewables actually might not be as bad as people thought,” he said.

Pair this news with another recent study, which found that solar’s EROI is better than most believed, and there’s another extremely convincing reason to accelerate a shift toward renewables, as these researchers suggest.