Guest post by John Morgan. John runs R&D programmes at a Sydney startup company. He has a PhD in physical chemistry, and research experience in chemical engineering in the US and at CSIRO. He is a regular commenter on BNC.
You can follow John on Twitter @JohnDPMorgan
Let’s get one thing out of the way – the parochial title. Graham Palmer’s Energy in Australia is not about Australia, any more than, say, David MacKay’s Sustainable Energy Without the Hot Air is about the UK. Both books make use of local case studies, but they are both concerned with fundamental aspects of our energy system that will interest readers regardless of nationality.
Likewise, peak oil and Asia’s economic growth are minor players in this story, characters that don’t really warrant top billing. So, what is this book really about?
EiA is an extended discussion of the high level issues in energy system transformation, in particular, energy return on energy invested (EROEI), intermittency, and electricity grid control. A short, punchy book of only 80 or so pages, it is broken down into many bite-sized pieces and is an easy read for the non-specialist, despite being published under an academic imprint.
The book argues that solar and wind exist within the existing fossil fuel / synchronous grid framework, and have a role to play in abating emissions from those plants, and in network peak load support, but that they do not allow us to break out of that system. That would require an energy source with high EROEI driving synchronous generators that can progressively replace those driven by coal and gas in the existing grid.
The system level issues are summarized by Palmer in the figure below, as they relate to plans for renewable energy. Many proposals for 100% renewable energy systems put together some combination of wind, solar, biogas, etc. that meets historical demand. As Palmer puts it,
The underlying theme of 100% renewable plans is the assumption that through increased complexity, an optimal set of synergies can be discovered and exploited. The difficulty is that the plans operate solely within the shallow “simulation layer” … With few exceptions, little consideration is given to the deeper first- and second-order layer issues.
The first half of the book explores those deeper issues, and is a fascinating description of the operation of the grid, its control schemes, the role of baseload, peak demand management, storage, capacity factors, availability and so on. This really should be compulsory reading for anyone serious about a transition to a low emissions electricity grid.
A startling figure from this discussion is the world’s electricity generation mix expressed, not as contributions from coal, gas, hydro, wind etc. as we usually see, but as the fraction from “synchronous rotary machines” – that is, mechanical generators with rotating shafts which are synchronized to the electrical frequency of the grid. 96% of global electricity is provided by such machines. In a sense, we have almost no diversity in electrical generation.
These machines are ubiquitous because they offer a solution to the historically difficult problem of grid control – making sure that electricity generation exactly meets demand at any instant. This is done by frequency stabilization – the rotation of all the generators on the grid is synchronized, and as loads are connected to the grid, the rotational frequency drops, which is the signal used to bring on board new generation.
The rotational inertia and frequency synchronization of these machines are critical to grid operation. Control problems arise when non-synchronous generators, such as most wind turbines, or non-inertial generators, such as solar photovoltaics, are added. The discussion of this and other kinds of non-obvious wind and solar integration issues, beyond simple capacity and intermittency, is one of the strengths of this book.
Intermittency can of course be addressed by energy storage, if its available. A case study of solar PV in Melbourne shows that solar output is poorly correlated with electricity demand, but with four hours of storage, solar power can usefully reduce peak demand. Palmer concludes that the most useful role for solar PV is peak demand management.
In another case study of King Island, an isolated grid with a high penetration of renewables, concludes that the grid control aspects can be technically overcome, but at very high cost. Even when renewables are displacing expensive diesel, which is perhaps their highest value context, the island’s income (from high value exports to the mainland) only covers 39% of the cost of electricity, the rest being subsidized.
The focus then moves to EROEI, possibly the most important metric to consider in energy system transformation. It takes energy to build any kind of power plant, so the plant had better be able to give at least that much energy back before it wears out, or the game isn’t worth the candle.
If the energy returned just balances the energy used to create it, the power plant has an EROEI of 1. It’s breakeven. And that’s not enough, because it also has to supply energy for the society that builds it. It has to power not just the construction of more power plants, but the homes, roads, schools, hospitals, clothes, cars, computers, armies, movie theatres, farms and all the elements of the civilization in which it is embedded.
There is a minimum EROEI required for an energy source to be able to support our present civilization. For countries like the US and Germany, this is estimated to be about 7. An energy source with lower EROEI cannot sustain a civilization at that level of complexity, structured along similar lines. If we are to transform our energy system, in particular to one without climate impacts, we need to pay close attention to the EROEI of the end result.
And here an analysis of the EROEI of solar leads to an uncomfortable conclusion: adding storage to solar PV reduces the EROEI, to just above 2. This is not enough net energy to be a viable energy source. Weißbach et al. found a similar result for wind, reporting an EROEI of 3.9 for wind with storage, below the viable threshold of 7. So the idea that advances in energy storage will enable renewable energy is a chimera – the Catch-22 is that in overcoming intermittency by adding storage, the net energy is reduced below the level required to sustain our present civilization.
How we get our energy is one of the most pressing questions we face today. Unfortunately the quality of the discussion in the media and elsewhere is, frankly, dire. A wider understanding of the topics treated Energy in Australia is sorely needed, and the book is highly recommended to anyone wanting to understand, and change, our energy systems.
(Footnote: For an introduction to the book by the author, Graham Palmer, read this BNC post)
Appendix – Twitter highlights from the book, by @JohnDPMorgan
“Although there are often instances of low-level correlation between various types of renewables, the correlations are very weak …”
“the high embodied energy of batteries results in only marginal emission gains of EVs over an equivalent fuel-efficient conventional vehicle
“Since all of the renewable plans rely heavily on intermittent generation, the definition of baseload has become blurred in recent years.”
96 % of global electricity is generated by synchronous rotary machines – thermal or hydro plant.
“Budischak et al. (2012) US renewables plan assumed 28.3 GW of fossil fuel plant would be retained, equal to about the average grid demand.”
“Such is the power & intuitive appeal of energy efficiency that it has been universally adopted as a key plank of the sustainability project
“The empirical evidence to date has been that energy efficiency has shown a steady improvement, yet emissions continue to rise”
“the state-imposed reliability standards are set very high due to the high cost for business of blackouts and the likely political fallout”
“the Australian reliability standard states that the maximum expected regional unserved energy should be no more than 0.002 %”
“Wind may have a capacity factor of 30 %, but an availability factor of <10 %, ie <10 % of the nameplate capacity can be relied upon…”
“in the Australian NEM, the capacity credit for wind ranges between 0.4 and 9.2 %, depending on the season and the state”
“most cost-of-intermittency assessments assume the availability of a highly reliable, adaptable grid based mostly on conventional generation
“households that produce twice the annual energy from solar that they consume, still import power from the grid for 63% of annual hours.”
Rooftop pv doesn’t reduce peak demand or network costs; add 4 hours storage and it does. pic.twitter.com/W4OAeqpOc6
“Unlike oil production, which has shown a long run secular decline in EROI, many renewable technologies have shown the inverse relationship”
“RE has not replaced conventional generation;wind & solar tend to add to the energy mix without forcing the retirement of conventional plant
“32% increase in German generation in 10 yrs, much of it wind and solar, big scaling up of transmission, but consumption has barely changed”
“Therefore, the cumulative embodied energy of the German electricity sector is increasing, but the energy output is not.”
This is a MAJOR problem with every life cycle analysis of renewables I’ve ever read -> “5.8 Conventional LCAs Ignore Intermittency”
“if all the grid connected solar PV in the world were switched off, there would be no noticeable difference in the functioning of society”
“little evidence of PV bootstrapping its own energy,powering mines,manufacturing,transport,& complex value chain req’d to deliver PV systems
How much material would Beyond Zero Emission’s zero carbon plan use for the concentrating solar thermal plants? A lot pic.twitter.com/gIKBio4OKQ
“BZE uses massive amts of materials that are heavily dependent on fossil-fuelled industry,provide limited scope to retreat from fossil fuels
“if the BZE plan were implemented over the 10 years, Australia’s steel demand could increase by 50 % as a consequence of the CST roll-out”
“The longevity (since 1881) of the lead–acid battery provides a reality check on the limits of technological innovation in energy storage.”
“Eisler’s 50-yr history of the hydrogen fuel cell provides an antidote to the idea that a revolution in storage is “just around the corner”
Solar power requires storage, but adding storage reduces the EROEI to below viable levels. Storage is not a panacea. pic.twitter.com/1X5igIqxbB
“The European experience with carbon taxes since the 1990s has been that carbon taxes do in fact reduce emissions”
“But the purpose [of carbon pricing] is not just to marginally reduce emissions, but change, in a fundamental way, the energy systems …”
“…renewable energy can provide abatement within a fossil-fuelled economy; CO2 pricing will be an effective marginal abatement strategy. But…
“But it is less clear that renewable energy can be an effective global energy strategy in an era of lowering EROEI”
“Sweden & France have near-zero emission intensity for electricity yet are still subject to EC requirements for expanding renewable energy”
“In many scenarios, it is clear that policy prescriptions can seek to maximize renewable penetration or maximize abatement, but not both.”
“the embodied emissions of renewable generation are not accounted for when ascertaining their competitiveness in the context of a CO2 price.
“Since 2007, 5 PMs & Opposition Ldrs have been deposed,in large part due to an inability to construct a coherent narrative on carbon pricing
“…solar essentially “buys abatement” but does not displace conventional generation capacity …” -Driving Down Emissions | Energy in Australia
Filed under: Emissions, Future, Renewables