Low-carbon energy transition requires more renewables than previously thought

May 7, 2018, Autonomous University of Barcelona

The transition to a low-carbon energy society will require more renewable energy sources than previous estimates if current levels of energy consumption per capita and lifestyles are to be maintained. This is one of the main conclusions of a study recently published in Nature Energy by Lewis King and Jeroen van den Bergh of the Institute of Science and Environmental Technology of the Universitat Autònoma de Barcelona (ICTA-UAB).

Following the Paris Agreement, several global transition scenarios have been presented. While these tend to be analysed in terms of gross energy, the authors of the study consider the need to calculate energy requirements by distinguishing between gross (total energy yielded) and net energy (gross energy minus the energy used to produce it). They also considered energy return on investment (EROI), which represents the amount of useful energy yielded for each unit of energy input in the process of obtaining that energy. The lower an energy source's EROI, the more energy input is required to produce a given energy output, resulting in less net energy available for consumption. According to researchers, coal and hydroelectricity have high EROIs, while nuclear energy, oil and gas have medium EROIs, and solar and wind power are characterized by medium to low EROIs.

The EROI level is important for a society's economy, welfare and lifestyle. Once requirements for basic consumption ("essentials") such as food and water are met, low-EROI economies would have less than half of the net energy of high-EROI economies available for consumption and production of all "non-essential" goods and services. This would have significant implications for lifestyles, and limit the ability to invest energy to achieve future economic growth.

Thus, in the face of a future scenario based on (with low-EROI rates), the researchers indicate that net energy per capita is likely to decline in the future between 24 percent and 31 percent from 2014 levels, unless substantial investments are made in .

"To maintain net energy per capita at current levels, renewable energy sources would have to grow at a rate two to three times that of current projections," states Lewis King. The results further indicate a prioritization in phasing out fossil fuels, namely first coal, then oil and finally gas. This can be achieved by implementing a carbon price, which would discourage coal use more than oil, and oil more than gas.

To improve lifestyles, a low-EROI society has three options: increase gross energy production, improve end use energy efficiency in production and consumption, or improve the average EROI considerably through technological improvements and investment in higher-EROI energy sources. "The challenge of a rapid transition to low-carbon energy is therefore twofold: staying within the carbon budget associated with accepted climate change targets (2ºC warming) while continuing to deliver net energy for the needs of a growing global society," says professor van den Bergh.

King and van den Bergh have developed a dynamic EROI model to analyze net energy supplied to society, considering both operational and investment costs. Moreover, the authors propose an indicator for on carbon (EROC), a metric of net energy per tCO2, to assist in maximizing potential net energy from the 2ºC carbon budget. This would allow comparison of the performance of different energy sources under the constraint of a climate change target. According to the EROC indicator, among fossil fuels oil shale and tar sands are very bad choices in terms of climate risks, while natural gas with CCS (carbon capture and storage) comes out best, considerably better than coal with CCS, and performing more than 10 times better than oil shale and tar sands.

Explore further: How useful is fracking anyway? Study explores return of investment

More information: Lewis C. King et al, Implications of net energy-return-on-investment for a low-carbon energy transition, Nature Energy (2018). DOI: 10.1038/s41560-018-0116-1

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4 comments

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WillieWard
2.3 / 5 (3) May 07, 2018
"Low-carbon energy transition requires more renewables than previously thought"
Translating: "Low-carbon energy transition requires more" ruination of natural landscapes, disruption of wildlife habitats, massacre of millions of birds and other endangered species, more subsidies/tax credits and more fossil fuels(manufacturing/mining/transporting/installing/recycling) "than previously thought" for almost nothing in terms of CO₂ reduction.
"They also considered energy return on investment (EROI), which represents the amount of useful energy yielded for each unit of energy input in the process of obtaining that energy. The lower an energy source's EROI, the more energy input is required to produce a given energy output, resulting in less net energy available for consumption. According to researchers, coal and hydroelectricity have high EROIs, while nuclear energy, oil and gas have medium EROIs, and solar and wind power are characterized by medium to low EROIs."
antialias_physorg
2.3 / 5 (3) May 07, 2018
coal and hydroelectricity have high EROIs

For both I'd like to see a calculation that includes the energy needed to mitigate (or outright clean up) the environmental damages. I'm pretty sure - at least for coal - that would change the numbers drastically.

The transition to a low-carbon energy society will require more renewable energy sources than previous estimates if current levels of energy consumption per capita and lifestyles are to be maintained.

We should also include the possibility of getting more efficient (i..e maintaining lifestyle even though energy footprint diminishes). There are developed countries that have wildly different energy footprints per capita even though their lifestyles are basically on par with each other (factor of 3:1 or more).
https://en.wikipe...r_capita

Also economic growth has become ever less strongly coupled to energy consumption over the past decades.
Ken_Fabian
not rated yet May 07, 2018
If we can't achieve a decent lifestyle with less energy we aren't trying. The link to the study didn't work, but I'd be interested to see the underlying assumptions, because RE costs are a moving - shrinking - target.

Irrespective of EROI the market effects of shrinking RE costs will snowball (with oversizing becoming cost effective). Growing penetration means emissions reductions flow to manufacturing. As storage kicks in FF plant will spend less time on standby - just 1 night of storage means switched off for day after sunny day - and a step in gains will become more apparent.

But I suspect the greatest near term contribution RE is making is political - the alarmist fears of extreme costs of strong climate action (along with climate science denial, the main thrust of opposition) are being undermined. Commerce and industry are no longer united in their opposition and their support for - and investment in - an energy transition is growing.
JustAnyone
5 / 5 (1) May 08, 2018
CCS IS FAKE! Carbon Capture and Storage (CCS) was invented by American Petroleum Institute (API) to pretend they're climate friendly, when they're Definitely NOT. It's NEVER BEEN USED COMMERCIALLY for any other purpose than pushing more oil out of the ground.

No consensus exists for it's adoption, it's propaganda pushed by API. All articles mentioning CCS should mention it's got 50 years of unproven claims and zero commercial and zero public acceptance. IMHO, like coal gasification, it should be utterly avoided since it's so associated with Press Release Journalism and API's public relations fakery. Sorry to blast here, but it pisses me off they're trying to push this stuff.

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