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| 1 |
ID:
150895
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| Summary/Abstract |
Fossil fuels face resource depletion, supply security, and climate change problems; renewable energy (RE) may offer the best prospects for their long-term replacement. However, RE sources differ in many important ways from fossil fuels, particularly in that they are energy flows rather than stocks. The most important RE sources, wind and solar energy, are also intermittent, necessitating major energy storage as these sources increase their share of total energy supply. We show that estimates for the technical potential of RE vary by two orders of magnitude, and argue that values at the lower end of the range must be seriously considered, both because their energy return on energy invested falls, and environmental costs rise, with cumulative output. Finally, most future RE output will be electric, necessitating radical reconfiguration of existing grids to function with intermittent RE.
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| 2 |
ID:
166723
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| Summary/Abstract |
A number of official energy forecasts—including those compatible with the aspirational 1.5 °C Paris Accord global temperature rise limit—see both global primary and net energy use continuing to rise, even out to 2100. Various technologies, including greatly increased use of renewable and nuclear energy, negative emission technologies such as direct air capture, and geoengineering are proposed as approaches for meeting the 1.5 °C target. In contrast, we argue that meeting this target and avoiding significant increases in extreme weather events will require marked reductions in future energy demand. We argue that the combined fossil fuel and renewable net green energy production will fall in the coming decades, after subtraction of various energy costs essential for ecosystems maintenance, including those needed to stabilise climate. At best, nuclear energy will only fractionally increase its global energy share, because of its high capital costs and political opposition arising from accident risks, waste disposal and proliferation concerns. Geoengineering will not solve fossil fuel depletion, and has serious known—and perhaps unknown—risks. We conclude that global net energy produced in an ecologically sustainable manner will start falling in a decade or so, and suggest the need to account for this at a policy level by introduction of a green EROI—EROIg.
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| 3 |
ID:
094206
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2010.
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| Summary/Abstract |
Recent research has shown that once CO2 has been emitted to the atmosphere, it will take centuries for natural removal. Clearly, the longer we delay deep reductions in CO2, the greater the risk that total greenhouse gas emissions will exceed prudent limits for avoiding dangerous anthropogenic change. We evaluate the three possible technical approaches for climate change mitigation: emission reduction methods, post-emission draw down of CO2 from the atmosphere, and geoengineering. We find that the first two approaches are unlikely to deliver the timely reductions in CO2 needed, while geoengineering methods either deliver too little or are too risky. Given the deep uncertainties in both future climate prediction and energy availability, it seems safest to actively plan for a much lower energy future. We propose a general 'shrink and share' approach to reductions in both fossil-fuel use and carbon emissions, with basic human needs satisfaction replacing economic growth as the focus for economic activity. Only with deep cuts in energy and carbon can we avoid burdening future generations with the high energy costs of air capture.
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| 4 |
ID:
104951
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2011.
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| Summary/Abstract |
Because continued heavy use of fossil fuel will lead to both global climate change and resource depletion of easily accessible fuels, many researchers advocate a rapid transition to renewable energy (RE) sources. In this paper we examine whether RE can provide anywhere near the levels of primary energy forecast by various official organisations in a business-as-usual world. We find that the energy costs of energy will rise in a non-linear manner as total annual primary RE output increases. In addition, increasing levels of RE will lead to increasing levels of ecosystem maintenance energy costs per unit of primary energy output. The result is that there is an optimum level of primary energy output, in the sense that the sustainable level of energy available to the economy is maximised at that level. We further argue that this optimum occurs at levels well below the energy consumption forecasts for a few decades hence.
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| 5 |
ID:
088241
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2009.
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| Summary/Abstract |
Several official reports on future global primary energy production and use develop scenarios which suggest that the high energy growth rates of the 20th century will continue unabated until 2050 and even beyond. In this paper we examine whether any combination of fossil, nuclear, and renewable energy sources can deliver such levels of primary energy-around 1000 EJ in 2050. We find that too much emphasis has been placed on whether or not reserves in the case of fossil and nuclear energy, or technical potential in the case of renewable energy, can support the levels of energy use forecast. In contrast, our analysis stresses the crucial importance of the interaction of technical potentials for annual production with environmental factors, social, political, and economic concerns and limited time frames for implementation, in heavily constraining the real energy options for the future. Together, these constraints suggest that future energy consumption will be significantly lower than the present level.
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