Making sense of the Tesla Triumvirate – solar, batteries and electric vehicles

Guest Post by Graham Palmer. Graham recently published the book “Energy in Australia: Peak Oil, Solar Power, and Asia’s Economic Growth” (“Springer Briefs in Energy” series).

The Tesla Powerwall is promised as the critical third key to unlocking the Tesla Triumvirate – solar, batteries and electric vehicles. The Powerwall provides an opportunity to look at the opportunities and weaknesses of distributed power, and examine the long-run sustainability of such a system. To do this, we can turn to life-cycle assessments and the field of Energy Return on Investment (EROI).

EROI is the ratio of how much energy is gained from an energy production process compared to how much of that energy is required to extract, grow, or get a new unit of energy. Advocates of EROI believe that it offers insights about energy transitions in ways that markets can not. The availability of surplus energy has been one of the main drivers of economic and social development since the industrial revolution.

At the start of the 1990’s, Pimentel launched a debate that was to be long running, on the effectiveness of corn ethanol production in the United States. Pimentel drew attention to the energy intensity of the ethanol life cycle, including nitrogen fertilizer, irrigation, embodied energy of machinery, drying, on-farm diesel, processing, etc. Although not settled decisively, there is a consensus that the EROI of US corn ethanol is below the minimum useful threshold. Brazilian ethanol seems to be better, and there is hope that second generation biofuels will be better again.

The relative fraction of residential energy end-use in Australia helps to give a sense of the scale between our direct household energy use, and the total energy consumption in Australia – according to the Bureau of Resources and Energy Economics (table 3.4), residential energy consumption made up 11% of total energy consumption, with electricity a little under half of that. As a community, the vast majority of our energy footprint is embedded in the goods, food, products, and services that we consume.

We can also apply EROI principles to electricity production. However electricity is only valuable within the context of a system and isolating the EROI of individual components is more challenging. We can, however apply life-cycle inventories to individual components, including solar, batteries, and electric vehicles, and see how they perform. Life-cycle assessments measure the lifetime environmental impacts of greenhouse emissions, embodied energy, ozone depletion, particulates, water and marine toxicity and eutrophication, and other effects.

The UK-based Low Carbon Vehicle Partnership compared a range of low emission vehicle options in the UK. This considered the full life-cycle of the vehicle including production of the vehicle with a driving range of 150,000km. The conventional vehicle was based on the VW Golf, and the electric vehicle was based on the Nissan Leaf.

Based on the current European grid, it concluded that EVs generally have lower life-cycle emissions than an equivalent petrol vehicle, but the outcome is dependent on the electricity grid and other factors. The report also projected the analysis out to 2030, assuming improvements in energy and vehicle technologies. For the ‘typical 2030’ scenario, the emission intensity of the UK and European grid was assumed to drop to between 0.287 and 0.352 kg CO2-e/kWh (around a third of Australia’s current emission intensity).

Figure 1 – lifetime greenhouse emission based on “typical 2030” scenario

Figure 1 – lifetime greenhouse emission based on “typical 2030” scenario

The most important outcome of these life cycle assessments is that the embodied energy of the battery and the emission intensity of the grid are the crucial determinants of the emission intensity of EVs. The report assumed a battery capacity of 24 kWh for the EV, or less than a third of the Tesla Model S battery.

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Less than the sum of its parts: Rethinking “all of the above” clean energy

Guest Post by John Morgan. John is Chief Scientist at a Sydney startup developing smart grid and grid scale energy storage technologies.  You can follow John on twitter at @JohnDPMorgan.

The fastest path to decarbonization would seem to be combining every kind of low carbon energy available – the so-called “all of the above” camp of clean energy advocacy.  The argument runs that different kinds of clean energy are complementary and we should build as much of each as we can manage.  This is not in fact the case, and I’ll show that a mix of wind and solar significantly decreases the total share of energy that all renewables can capture.  The “all of the above” approach to emissions reduction needs to be reconsidered.

In a recent essay Breakthrough Institute writers Jesse Jenkins and Alex Trembath have described a simple limit on the maximum contribution of wind and solar energy: it is increasingly difficult for the market share of variable renewable energy [VRE] sources to exceed their capacity factor.  For instance, if wind has a capacity factor of 35%, this says it is very difficult to increase wind to more than 35% of electrical energy.  Lets look at why this is so, and extend the principle to a mix of renewables.

The capacity factor (CF) is the fraction of ‘nameplate capacity’ (maximum output) a wind turbine or solar generator produces over time, due to variation in wind, or sunlight.  Wind might typically have a CF of 35%, solar a CF of 15% (and I’ll use these nominal values throughout).

Jesse and Alex’s “CF% = market share” rule arises because it marks the point in the build out of variable renewables at which the occasional full output of wind and solar generators exceeds the total demand on the grid.

At this point it gets very hard to add additional wind or solar.  If output exceeds demand, production must be curtailed, energy stored, or consumers incentivized to use the excess energy.  Curtailment is a direct economic loss to the generators. So is raising demand by lowering prices.  Energy storage is very expensive and for practical purposes technically unachievable at the scale required.  It also degrades the EROEI of these generators to unworkable levels.

Jesse and Alex make this argument in detail, backed up with real world data for fully connected grids (i.e. not limited by State boundaries), with necessary qualifications, and I urge you to read their essay.

The “CF% = market share” boundary is a real limit on growth of wind and solar.  Its not impossible to exceed it, just very difficult and expensive. Its an inflexion point; bit like peak oil, its where the easy growth ends.  And the difficulties are felt well before the threshold is crossed.  I’ve referred to this limit elsewhere as the “event horizon” of renewable energy.

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Potential for worldwide displacement of fossil-fuel electricity by nuclear energy in three decades based on extrapolation of regional deployment data

Hot on the heels of my previous collaboration with Dr Staffan Qvist (from Uppsala University) on the implications of phasing out nuclear energy in Sweden, I’ve just had published another new open access paper on energy policy, this time in the peer-reviewed journal PLoS ONE. You can read it in full here.

Some details:

Citation: Qvist S.A. & Brook B.W. (2015) Potential for Worldwide Displacement of Fossil-Fuel Electricity by Nuclear Energy in Three Decades Based on Extrapolation of Regional Deployment Data. PLoS ONE 10(5): e0124074. doi: 10.1371/journal.pone.0124074

Swedish total CO2 emissions and GDP per capita 1960–1990, normalized to the level of 1960.

Swedish total CO2 emissions and GDP per capita 1960–1990, normalized to the level of 1960.


There is an ongoing debate about the deployment rates and composition of alternative energy plans that could feasibly displace fossil fuels globally by mid-century, as required to avoid the more extreme impacts of climate change. Here we demonstrate the potential for a large-scale expansion of global nuclear power to replace fossil-fuel electricity production, based on empirical data from the Swedish and French light water reactor programs of the 1960s to 1990s. Analysis of these historical deployments show that if the world built nuclear power at no more than the per capita rate of these exemplar nations during their national expansion, then coal- and gas-fired electricity could be replaced worldwide in less than a decade. Under more conservative projections that take into account probable constraints and uncertainties such as differing relative economic output across regions, current and past unit construction time and costs, future electricity demand growth forecasts and the retiring of existing aging nuclear plants, our modelling estimates that the global share of fossil-fuel-derived electricity could be replaced within 25–34 years. This would allow the world to meet the most stringent greenhouse-gas mitigation targets.

The key finding is that even a cautious extrapolation of real historic data of regional nuclear power expansion programs to a global scale, as shown in the table below, indicate that new nuclear power could replace all fossil-fuelled electricity production (including replacing all current nuclear electricity as well as the projected rise in total electricity demand) in about three decades—that is, well before mid-century, if started soon. This complements earlier top-down work I’d published on 2060 scenarios.

Time to replace global fossil electricity and current nuclear fleet.

Time to replace global fossil electricity and current nuclear fleet.

The methods of the paper are explained in detail, and I’d be happy to debate our assumptions.

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Environmental and health impacts of a policy to phase out nuclear power in Sweden

With Dr Staffan Qvist from Uppsala University, I’ve just had published a new open access paper in the peer-reviewed journal Energy Policy. It examines the ramifications of the announced policy by the Swedish Greens Party (who is part of the current coalition government) to phase out nuclear energy in Sweden. Their platform is: “we oppose the construction of new reactors in Sweden, or an increase in the output of existing reactors, and instead want to begin immediately phasing out nuclear power.”

The electricity mix of Sweden is a leading example of a successful historical pathway to decarbonisation.

Some details on our paper:


Qvist, S.A. & Brook, B.W. (2015) Environmental and health impacts of a policy to phase out nuclear energy in Sweden. Energy Policy, 84, 1-10. doi: 1016/j.enpol.2015.04.023


• The Swedish reactor fleet has a remaining potential production of up to 2100 TWh.

• Forced shut down would result in up to 2.1 Gt of additional CO2 emissions.

• 50,000–60,000 energy-related-deaths could be prevented by continued operation.

• A nuclear phase-out would mean a retrograde step for climate, health and economy.


Nuclear power faces an uncertain future in Sweden. Major political parties, including the Green party of the coalition-government have recently strongly advocated for a policy to decommission the Swedish nuclear fleet prematurely. Here we examine the environmental, health and (to a lesser extent) economic impacts of implementing such a plan. The process has already been started through the early shutdown of the Barsebäck plant. We estimate that the political decision to shut down Barsebäck has resulted in ~2400 avoidable energy-production-related deaths and an increase in global CO2 emissions of 95 million tonnes to date (October 2014). The Swedish reactor fleet as a whole has reached just past its halfway point of production, and has a remaining potential production of up to 2100 TWh. The reactors have the potential of preventing 1.9–2.1 gigatonnes of future CO2-emissions if allowed to operate their full lifespans. The potential for future prevention of energy-related-deaths is 50,000–60,000. We estimate an 800 billion SEK (120 billion USD) lower-bound estimate for the lost tax revenue from an early phase-out policy. In sum, the evidence shows that implementing a ‘nuclear-free’ policy for Sweden (or countries in a similar situation) would constitute a highly retrograde step for climate, health and economic protection.

You can read the full paper here.

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International Experience with Fast Reactor Operation & Testing

Below is a highly informative presentation given by Dr John Sackett (Idaho National Laboratory, Retired) at the International Conference on Fast Reactors and Related Fuel Cycles (Paris, 2013). John, with a 34-year career in advanced reactor and fuel-cycle development (including work on the Integral Fast Reactor from 1984-1994), provides a clear summary of historical-international experience with fast reactor programmes and initiatives to recycle used fuel.

This is important information for advocates of ‘Generation IV’ nuclear technologies to understand, because the question of “is it proven to work?” is often asked by the skeptical. Much of this will be familiar to those who have read “Plentiful Energy“, but this is an excellent condensed version of that material. This is also highly relevant in the context of the recently commenced Nuclear Fuel Cycle Royal Commission.

There is a Long History of Fast Reactor Operation
• The first reactor in the world to produce electricity was a fast reactor, the Experimental Breeder Reactor I in December of 1951.
• International experience with fast reactor technology exists in the US, Russia, France, Japan, UK, Germany and India.
• The operating experience with these reactors has been mixed: early problems were associated with fuel cladding, steam generators, fuel handling, and sodium leakage.
• Excellent experience has been gained, however, that demonstrates the robust nature of the technology, the potential for exceedingly safe designs, ease of maintenance, ease of operation and the ability to effectively manage waste from spent fuel.
• It is a mature technology.

EBR-II was a Major Contributor to the Technology
• EBR-I was followed by EBR-II, which was a complete power plant. It was extremely successful, operating for 30 years and advancing the technology in many ways.
• Principal among its contributions were development of metal and oxide fast-reactor fuel, operational-safety tests which demonstrated the self-protecting nature of fast reactors, and fuel-recycle technology that was efficient and secure.
• Perhaps the most important advance in safety was the demonstration of the self -protecting response of sodium-cooled fast reactors in the event of Anticipated Transients without Scram.
• Tests of Loss of Flow without Scram and Loss-of –Heat-Sink without Scram were conducted at EBR-II from full power with no resulting damage to fuel or systems, ushering in worldwide interest in passively safe reactor design.

International Experience Compliments These Examples
• This experience base is fully supported by a combination of small test reactors that explored all aspects of the technology and larger operating reactors that provided power to the electric grid.
• Small experimental reactors were operated in the US (EBR-II), France (Rapsodie), Russia (BOR-60), Japan (JOYO), UK (DFR), Germany (KNK-II), and India (FBTR).
• Power reactors and larger experimental reactors were operated in the US (FERMI1, FFTF), France (Phenix, Superphenix), Russia (BN350, BN600), Japan (Monju). Current operating Fast Reactors are China (CEFR), and Russia (BN600, BOR60)

EBR-II_SiteUS Experience Followed Two Paths
• The US carried forward two separate tracks of technology development, primarily associated with the choice of fuel, metal or oxide.
• The first US commercial fast reactor, Fermi-I utilized metal fuel while the Fast-Flux-Test-Facility (FFTF) and the Clinch River Breeder Reactor (CRBR) utilized oxide fuel.
• Due to perceived low burnup potential for metal fuel, (a problem later solved), the U.S. approach turned to oxide fuel in the late 1960s.
• Russia, France, Germany and Japan all follow technology paths that use oxide fuel.
• It is worthwhile expanding this point because diversion of the technology paths has resulted in very different designs and performance, with the result that EBR-II is somewhat unique in this family of reactors.

Dry Reprocessing of EBR-II Fuel was Demonstrated in the 1960s
• Melt Refining was used to recycle fuel for EBR-II from 1964 through 1969
– More than 700 EBR-II fuel assemblies recycled using melt refining and returned to the reactor in four to six weeks
– ~34,000 fuel pins successfully reprocessed, including remote fabrication by injection casting
– Spent fuel was disassembled, chopped, placed into a Zr2O crucible, and heated to 1400 C
– Chemically reactive fission products reacted with the crucible to form oxides
– Uranium and noble metals remained in the metallic state and stayed with the melt to be returned with the re-cast fuel pins
– The fuel was fabricated remotely by injection casting, the resulting equilibrium fuel composition, called fissium, operated through the life of EBR-II. Continue reading