Net energy analysis must not compare apples and oranges

Raugei, Marco

doi:10.1038/s41560-019-0327-0

Cited by 62 publications

(51 citation statements)

References 20 publications

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“…Assessing rapeseed production for biodiesel in Europe van Duren et al (2015) concluded that the maximum gross EROI was 2.2:1. Though further work is required to align all studies system boundaries, ensuring no overestimations and no 'apples-tooranges' comparisons (Murphy et al 2016;Raugei 2019), these estimates evidence the limited capacity of biofuel production to maintain a sufficient net energy supply to society.…”

Section: Is Global Aaff Approaching Biophysical Limits?mentioning

confidence: 98%

A Net Energy Analysis of the Global Agriculture, Aquaculture, Fishing and Forestry System

Marshall

Brockway

2020

Biophys Econ Sust

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The global agriculture, aquaculture, fishing and forestry (AAFF) energy system is subject to three unsustainable trends: (1) the approaching biophysical limits of AAFF; (2) the role of AAFF as a driver of environmental degradation; and (3) the long-term declining energy efficiency of AAFF due to growing dependence on fossil fuels. In response, we conduct a net energy analysis for the period 1971-2017 and review existing studies to investigate the global AAFF energy system and its vulnerability to the three unsustainable trends from an energetic perspective. We estimate the global AAFF system represents 27.9% of societies energy supply in 2017, with food energy representing 20.8% of societies total energy supply. We find that the net energy-return-on-investment (net EROI) of global AAFF increased from 2.87:1 in 1971 to 4.05:1 in 2017. We suggest that rising net EROI values are being fuelled in part by 'depleting natures accumulated energy stocks'. We also find that the net energy balance of AAFF increased by 130% in this period, with at the same time a decrease in both the proportion of rural residents and also the proportion of the total population working in AAFF-which decreased from 19.8 to 10.3%. However, this comes at the cost of growing fossil fuel dependency which increased from 43.6 to 62.2%. Given the increasing probability of near-term fossil fuel scarcity, the growing impacts of climate change and environmental degradation, and the approaching biophysical limits of global AAFF, 'Odum's hoax' is likely soon to be revealed.

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Section: Is Global Aaff Approaching Biophysical Limits?mentioning

confidence: 98%

A Net Energy Analysis of the Global Agriculture, Aquaculture, Fishing and Forestry System

Marshall

Brockway

2020

Biophys Econ Sust

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“…However, the NEA literature has historically been characterized by a much lower degree of standardization than the LCA one, which has led to many inconsistent comparisons [71,72].…”

Section: Net Energy Analysis (Nea)mentioning

confidence: 99%

Life-Cycle Carbon Emissions and Energy Return on Investment for 80% Domestic Renewable Electricity with Battery Storage in California (U.S.A.)

et al. 2020

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This paper presents a detailed life-cycle assessment of the greenhouse gas emissions, cumulative demand for total and non-renewable primary energy, and energy return on investment (EROI) for the domestic electricity grid mix in the U.S. state of California, using hourly historical data for 2018, and future projections of increased solar photovoltaic (PV) installed capacity with lithium-ion battery energy storage, so as to achieve 80% net renewable electricity generation in 2030, while ensuring the hourly matching of the supply and demand profiles at all times. Specifically—in line with California’s plans that aim to increase the renewable energy share into the electric grid—in this study, PV installed capacity is assumed to reach 43.7 GW in 2030, resulting of 52% of the 2030 domestic electricity generation. In the modelled 2030 scenario, single-cycle gas turbines and nuclear plants are completely phased out, while combined-cycle gas turbine output is reduced by 30% compared to 2018. Results indicate that 25% of renewable electricity ends up being routed into storage, while 2.8% is curtailed. Results also show that such energy transition strategy would be effective at curbing California’s domestic electricity grid mix carbon emissions by 50%, and reducing demand for non-renewable primary energy by 66%, while also achieving a 10% increase in overall EROI (in terms of electricity output per unit of investment).

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“…Although there are standards recommending methods to compile energy statistics [29], conflicting approaches remain between major groups in the calculation of the contribution to global primary energy from non-thermal electricity sources such as from hydro, wind and photovoltaic (PV) cells [11], see Table 1. These conflicts are inevitable, given that as Raugei [30] has pointed out comparing electricity and thermal energy is like counting 'apples and oranges' together. The IEA [2] method converts primary electricity to primary energy on a 1:1 basis, although for all thermal sources of electricity, whether FF, RE, or nuclear, the input heat energy is used based on a conversion efficiency of 33%.…”

Section: Treatment Of Primary Re Electricitymentioning

confidence: 99%

Energy Accounting for a Renewable Energy Future

Moriarty

Honnery

2019

Energies

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For millennia, humans relied almost entirely on renewable energy (RE), largely biomass, for their energy needs. Over the past century, fossil fuels (FFs) have not only largely replaced RE, but have enabled a many-fold rise in total energy use. This FF dominance changed the way we think about and accounted for energy use. If (as at present) the world essentially continues to ignore climate change, eventual resource depletion will force conversion to RE and, perhaps, nuclear energy will once again have to provide most of the world’s energy use. However, the change is more likely to come about because of the urgent need for climate change mitigation. At present, primary RE electricity accounting is done by calculating the FF energy that would be needed to produce it. But as FFs disappear, this approach makes less sense. Instead, a new approach to energy accounting will be needed, one that allows for the intermittent nature of the two most abundant RE sources, wind and solar power. Surplus intermittent RE might be converted to H2, further complicating energy accounting. An additional complication will be the treatment of energy reductions, especially from passive solar energy, likely to be more important in the coming decades. This paper is a review of the evidence to try to determine the best approach to future energy accounting.

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Net energy analysis must not compare apples and oranges

Cited by 62 publications

References 20 publications

A Net Energy Analysis of the Global Agriculture, Aquaculture, Fishing and Forestry System

A Net Energy Analysis of the Global Agriculture, Aquaculture, Fishing and Forestry System

Life-Cycle Carbon Emissions and Energy Return on Investment for 80% Domestic Renewable Electricity with Battery Storage in California (U.S.A.)

Energy Accounting for a Renewable Energy Future

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