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Bringing the “Unruly Sun” to Heel: Is Solar Energy Worth the Candle?

Dr John Constable: GWPF Energy Editor

The wind industry is faltering as the mixed results of the mass deployment of the last twenty years become more widely known, but enthusiasm for solar energy is growing in its place. Is it any more promising? Even some of solar’s more enthusiastic proponents, such as Dr Varun Sivaram, whose new book, Taming the Sun: Innovations to Harness Solar Energy and Power the Planet (MIT Press: Cambridge Mass: 2018), is reviewed here, are open about the scale of the problems. But they are also asking for a correspondingly dramatic redesign of the world economy in order to bring about the solar revolution. Should we let them have their way? Dr Sivaram’s useful study helps us to reach a conclusion.

Solar energy has a powerful attraction for those thinking on the grand scale. Indeed, the bigger the picture, the more uncompromising the emphasis. Eric Chaisson, an American astrophysicist and well-known writer of Big History, has even gone so far as to predict that the development of solar power is the next necessary and indeed ultimate step after “wheels, agriculture, metallurgy, machines, electricity and nuclear power”, since “all intelligent civilizations, anywhere in the Universe, likely learn to exploit the energy of their parent star” (Eric J. Chaisson, Cosmic Evolution (Harvard UP: Cambridge Mass. 2001), 207).

Part of the attraction is that the use of solar energy is both very new and very old, a striking novelty that is also comfortably familiar. The photovoltaic effect was discovered only in the nineteenth century, making it the sole renewable with any claim to being a comparatively young technology, and yet life has in fact been exploiting the energy of the parent star, and with increasing sophistication, for as long or nearly as long as there has been life on earth. Photosynthesis creates cell structures rich in energy that are eaten or used by other creatures, whose own energy rich cells then provide resources for yet other creatures. Behind it all stands the sun. Humans have learned how to farm this process to their own advantage, greatly enlarging their population and even developing technologies that enable them to use the solar energy remaining in the compressed and transformed debris of prehistoric life, in coal, oil, and methane. A trace contribution from the gravitational energy of the moon, and more recently the use of sub-atomic energy, does not change the fact that the organic record on earth is that of solar energy transformations.

The generation of electricity from solar cells, therefore, is, and in spite of its technical novelty, felt as reassuringly consistent with the deep historical and prehistorical trends. Consequently it is seen as “natural”, and in this respect it stands in sharp contrast to nuclear sources, for which there is no precedent in post-photosynthetic life. Even it were to be widely agreed that life originated from thermophilic subsea creatures, drawing their energy from the heat resulting from radioactive decay of the earth’s core, there seems little likelihood that man will, on the grounds of that deep, foundational antiquity, come to be accustomed to energy from within the atom.

So when Chaisson and others suggest that the use of solar energy is the requisite, perhaps the culminating step in societal development, they are not, in spite of the rhetoric, offering anything profoundly unusual. Indeed, the fundamental lack of novelty is what makes it so winning. Humans and other organisms have been successfully learning to exploit the resources of our star for a very long time. We imagine, consequently, that a bit more of that won’t do us any harm; it goes with the grain; indeed, it is almost as if the universe were inviting and encouraging this line of development.

However, this apparent unadventurousness tends to distract from the one area in which the solar energy proposal really is strikingly different from all our earlier uses, from crops to coal. At the larger scales all those earlier utilisations of solar energy employed the complex, evolved structures of living organisms as intermediaries between the human user and the sun, this intermediary function serving to concentrate and store the energy in a form that was convenient. In the case of fossil fuels the accumulated organic stocks deposited over very long periods of time were further concentrated by geological processes, yielding an easily stored resource of very high energy density. A litre of crude oil contains about 38,000,000 joules. By contrast, solar energy arriving at the surface of the earth is not only a variable flux, but has a low spatial density. In the United Kingdom, for example, it arrives on the land at a rate of about 100 joules per second (watts) per square metre (David J. C. Mackay, Sustainable energy – Without the hot air (UIT: Cambridge, 2009), 38). The transformational space, the improbability, between these two extremes is extraordinarily large.

The solar proposal, therefore, is not about the use of a fresh source of energy, but about the use of novel, humanly engineered means to rectify the temporal and spatial deficiencies of the solar flux as it arrives on earth. Solar energy as it reaches us is not the “busy”, energetic and “unruly” intruder that John Donne thought it to be. Nor is it wildly powerful and in need of domestication, as the energy commentator Dr Varun Sivaram, of the Council on Foreign Relations, suggests in the title of his recent book, Taming the Sun (MIT Press: Cambridge Mass: 2018). On the contrary, solar energy doesn’t need watering down for human consumption. In fact, it is a rather feeble source that has never been much use to humankind until it has been distilled by the improbable structures of living creatures, and, even better, geologically cellared for several million years.

Just how difficult it will be for human technology to supply the role of plants, animals, time, and the pressure and heat of the rocks, can be inferred from Dr Sivaram’s book, which in spite of being an extremely enthusiastic argument for solar energy, does admit and describe the problems. The uncontrollable, non-despatchable character of solar generation is a nightmare. Describing real world experience in the state of California he notes that solar:

“places onerous, destructive demands on the nonsolar generators serving the grid. Meeting the ramp requirement […] requires an army of power plants – mostly fueled by natural gas – that are idling until late afternoon, when they all have to start rapidly injecting power into the grid. This inefficient use of resources is expensive, entailing paying a fleet of generators to wait around until they are needed. And repeating this cycle every day induces wear and tear in power plants that are much happier if they are producing a steadier output with gentle changes. None of these costs show up in the sticker price of solar panels, but solar imposes them on the grid nevertheless. Several studies have aimed to quantify these costs, and a typical estimate is that solar becomes up to 50 percent more expensive when the additional costs of integrating it onto the grid are taken into account.” (pp. 75–76)

Mr Sivaram continues, noting that “In addition to imposing costs on the grid, rising solar penetration could make the grid less reliable”, it “can overload local distribution circuits” causing the inverters that connect solar panels to the system to “shut down all at once, causing a blackout” (77). And such problems are not confined to the local level. At the national scale,  Dr Sivaram reports that solar surges in Germany have resulted in unwelcome exports and disturbances in the grid systems of Hungary, Poland, the Czech Republic and Slovakia. In review, he usefully summarises the current solar situation and its implications:

All of these issues are daunting headaches that are on track to accompany the rise of solar. So far, only a few frontier markets – most notably, California and Germany – have experienced them. But if solar is to increase is penetration around the world, it will impose economic and technical costs on power grids everywhere. (p. 78.)

No wonder, then, that he foresees the real possibility that “today’s red-hot solar market could cool down tomorrow” (p. xvi). His reaction to these facts is to recommend public spending on the very largest scale, not only in Research & Development but also in deployment. Otherwise, he believes that the solar industry will only grow to the point at which the value of its electricity starts to fall. This will at best cause stagnation and possibly the collapse of the solar sector. His own account of this decline in the market value of the electrical energy for solar generation is ingenious – he uses the term “value deflation” (71ff) – but perhaps only restates what we knew already. Namely, that while mandated solar remains at modest levels of penetration the low economic value of its uncontrollable output is masked both by the regulatory coercion that forces it into the market and the fact that it is the residual, conventional sector which takes up the slack and is consequently harmed. After a certain point, the truth can no longer be concealed and further solar starts to destroy its own viability.

However, Mr Sivaram believes that this transitional hazard can be overcome by vast government funding to develop the root and branch, system wide, redesign of the entire electricity system, from producer to consumer. Three kinds of “innovation” are required:

[…] financial innovation to recruit massive levels of investment in deploying solar energy; technological innovation to harness the sun’s energy more cheaply and store it to use around the clock; and systemic innovation to redesign systems like the power grid to handle the surges and slumps of solar energy

In its scope this is comparable to “Life, the Universe and Everything”, and it is obvious that more than innovation, in the strict sense, is required. A great deal of what is implied in the required technological and systemic development is radical, creative invention, not the straightforward though novel assemblage of relatively well understood components that is innovation.

Dr Sivaram’s lucid combination of candour about the problems and can-do enthusiasm for their solution is very engaging, but the probable hazards are so likely and so large that he will only persuade the naïve, admittedly a large constituency. One can appreciate this by thinking of the matter in terms of what evolutionary biologists would term the adaptive landscape. As solar grows it will be faced with a deep valley, a decline in its fundamental viability, but Dr Sivaram believes that on the other side of this impassable valley he can see a very promising mountain peak on which solar generation powers a prosperous and clean economy rich in human wellbeing. The sort of technological progress normal to power systems development will clearly not carry solar through the low fitness valley, so Dr Sivaram urges state funding to bridge the gap by transforming everthing related to the solar sector, the financial system, the technologies employed, and the  grid and market system that serves consumers. He grants that the details of these transformations are as yet unknown, but claims that the direction of travel required to reach the sunlit upland destination is obvious and obviously desirable. All we have to do is make the effort.

In response one might point out that this would be quite unlike any previous experience in learning to use the energy of our star. We made progress in relatively slow increments, with each increment being in itself beneficial, yielding returns for the populations then living and preparing for the next technological increment through the creation of additional wealth. Every stage of the transition paid its way. The use of coal began in situations of simple, open, combustion for heat, requiring low technology and delivering modest but real benefits that gradually enriched the societies that used it. This in turn led to the construction of more complex systems, steam engines, that were capable of deriving much greater benefits from coal, and producing mechanical and then electrical energy, and so on to the very sophisticated systems needed to use oil and gas. But those inventors improving steam engines in the mid-nineteenth century did not see themselves as working towards the oil age. They did not see themselves as mere transitional steps, valueless in themselves but justified because on a path leading to a far off peak. Every move they made was in itself valuable, and would have been worth undertaking even if there had been no oil age and no gas age in the future.

Dr Sivaram, in contrast, is asking for an intrinsically unrewarding and painful macro-saltation, a societal and systemic transformation, a jump across an abyss to a mountain top called the solar economy. The effort, the immense cost and its implied sacrifices, which he glosses over, would only be justified by the end, a successful landing on the promised peak. However, there is a significant probability that the transformation called for will fail; we might fall into the abyss and be unable to get back to where we started. Moreover, even if we sail over what we take to be the abyss no one can guarantee that the peak will actually be there for us to land on, or, if there, that it will be an attractive or stable location. There may be no peak at all, no viable solar economy; and even if there is it may be very inhospitable, delivering a way of life that is extremely unappealing to the human populations.

To Dr Sivaram all of these reservations will seem annoyingly negative and without vision. He writes with entrepreneurial conviction, and we would be lost in the absence of such people. Without risk takers none of the incremental, beneficial steps in the coal and oil and gas transitions would have been found. But however courageous the engineers and investors were in pushing forward with their ventures, the wider society was not exposed to unacceptable risk. In contrast, by insisting that the entrepreneurial model be applied at the state level, Dr Sivaram invites us to hazard societal wellbeing on his vision. He freely admits that he has no idea of the details of all the new technologies that need to be discovered. The solar industry that he prophecies in cloudy outline would be, he tell us,  “unrecognisable” in comparison with that around us today (p. 274). In the excitement, however, he seems to forget that we may not find what we want and that we may not like what we can find. And in fact he has no idea, because it is in principle unknowable so far in advance, if there is even an attractive solar economy to be won. Perhaps there is, perhaps not. For my own part, I think it very unlikely on physical grounds. The scale of capital equipment required to rectify the extremely problematic, thin flows of solar energy will be vast, suggesting a low productivity energy sector engrossing the vast majority of all the capital wealth that can be sustained in that society. Very little will be left over for other activities, and the whole system will present the sharpest possible contrast with the present situation, where Big Fossil may be a giant, but is dwarfed by the non-energy economy made possible by fossil fuel’s large Energy Return on Energy Invested.

Indeed, it is not quite certain that the solar economy would even be self-reproducing. In other words, it is by no means self-evident that a solar economy, having been generated by the conventionally fuelled economy and its legacy wealth, could be self-sustaining in the long term absence of fossil fuels. Loose gestures towards technological progress offer no reassurance on this point. Any kind of sophistication, including scientific and technological sophistication, is hard won and only retained by continual repair and replication in institutions, in human minds, and in technical practise. Maxwell’s, Einstein’s equations are cheap to preserve on paper, of course, but maintaining a population of engineers and physicists capable of understanding and applying them through a network of competent industries is extremely costly indeed. Technology is not a spirit.

It is therefore a clear theoretical possibility that the solar economy would not deliver sufficient energy to repair and maintain the advanced technological capital structures required for its own survival, let alone provide a surplus enabling human societies to do all the other work necessary for supporting a prosperous and healthy population. Such a system might well contract, perhaps rapidly (one climbs slowly, but falls fast). This is a very unpleasant prospect, and even if just stable the system is unlikely to be robust, and could be fragile in the presence of exogenous shock, much as the solar-dependent agricultural, organic societies of the past were vulnerable. These undesirable outcomes seem to me more likely than not, but even if you thought such hazards only a ten per cent probability, that would be altogether too risky for a public policy decision maker. There is just too much at stake. This isn’t a normal business risk.

Simply, then, very little is known about the feasability or desirabilty of the electricity system transformation required to accommodate large scale solar energy, and no one has any idea if there is a viable let alone an attractive sunshine fuelled economy at the end of it. The solar leap that Dr Sivaram’s lively and very readable book urges us to make is paradoxically but very truly a “great leap in the dark”. The author of Leviathan, whose last words those are, had no choice: he was dying. Happily, we have other prospects.