In the last three decades considerable concern has emerged regarding limits to the future availability of energy in the quantities required by industrial-affluent societies. More recently Campbell (1997) and others have argued that the energy source on which industrial societies are most dependent, petroleum, is more scarce than had previously been thought, and that supply will probably peak between 2005 and 2015 (Fleay, 1995, Ivanhoe, 1995, Gever, et al., 1991, Hall, Cleveland and Kaufman, 1986, Laherrere, 1995, Duncan, 1997, Bentley, 2002, Youngquist, 1997). Some of these people argue that the world discovery rate is currently about 25% of the world use rate, and that non-conventional sources such as tar sands and shale oil will not make a significant difference to the situation. The USGS (2000) has recently arrived at a much higher estimate for ultimately recoverable petroleum, but this would only delay the peak by some 10 years.
If the discussion is expanded to take into account the energy likely to be required by the Third World, the situation becomes much more problematic. If the present world population were to consume energy at the rich-world per capita rate, world supply would have to be five times its present volume. World population is likely to reach 9.4 billion by 2070. If all these people were to consume fossil fuels at present, rich-world per capita consumption rates, all probably recoverable conventional, oil, gas, shale oil, uranium (through burner reactors), and coal (2000 billion tonnes assumed as potentially recoverable), would be totally exhausted in about 20 years (Trainer, 1985, Ch.4).
What is not well understood is the magnitude of the overshoot, the extent to which our present consumer society has exceeded sustainable levels of resource use and environmental impact. This is made clear by a glance at the greenhouse problem. The Inter-governmental Panel on Climate Change (IPCC 2001, 2005, see also Enting, et al., 1994) has given a range of emission rates and the associated levels that the carbon dioxide concentration in the atmosphere would rise to.
• Perhaps the most quoted graph shows that if the concentration is to be stabilised at 550 ppm, twice the pre-industrial level, emissions must be cut to 2.5 Gt/y by 2040 and to 0.2 Gt/y by about 2200. The present level from fossil fuel burning (i. e., not including land clearing) is over 6 GT/y.
• To keep the concentration below 450 ppm, emissions must be cut to about 1 + Gt/y by 2100, and to about 0.3 Gt/y by 2200. This target is much too high because the atmospheric concentration is now at about 380 ppm and many disturbing climatic effects are becoming apparent.
• The limit now often referred to as the maximum before catastrophic effects are risked, such as the cessation of the Gulf Stream, is 400 ppm, associated with a 2 degree rise in temperature.
• If we were to stabilise the concentration at about the present level we would have to cut emissions to about 0.5Gt/y by around 2040, and for some decades after 2070 we would have to extract more carbon from the atmosphere than we added.
It would seem clear therefore that our target should be at most 2 Gt/y, but a more sensible target would be closer to 0.5 Gt/y. Yet what is the input that the Australian Bureau of Agricultural and Resource Economics estimates we are heading for by 2050? An alarming 15 Gt/y.
If world population reaches 9+ billion, a global carbon use budget of 1 Gt would provide us all with about 150 kg of fossil fuel per year, which is around 2-3% of our present rich-world per capita use of fossil fuels (in GHGe terms). Alternatively only about 170 million people, 2.5% of the world’s present population, could live on the present rich-world per capita fossil fuel use of over 6 tonnes of fossil fuel per year.
These figures define the enormous magnitude of the sustainability problem we confront. Consumer-capitalist society has overshot viable levels of production and consumption by a huge amount. In effect we have to give up fossil fuels altogether. That is, we have to live almost entirely on renewables. This book argues that these very high levels of production and consumption and therefore of energy use that we have in today’s consumer-capitalist society cannot be sustained by renewable sources of energy.
However the foregoing numbers only define the magnitude of the present problem. This is nothing like the magnitude of the problem set when our commitment to growth is also taken into account. As will be detailed in Chapter 10, if 9.4 billion people are to have the “living standards” we in rich countries will have by 2070 given 3% economic growth, total world economic output every year would then be 60 times as great as it is now.
The question of whether we can run our society on renewable energy is therefore not about whether it can meet present demand, and this book concludes that it cannot do that, it is about whether it can meet the vastly increased demand that will be set by the pursuit of limitless increase in production and consumption.
There is an overwhelmingly powerful, never questioned, assumption that all these problems can and will be solved by moving to renewable energy sources. That is, it is generally believed that sources such as the sun and the wind can replace fossil fuels, providing the quantities of energy that consumer society will need, in the forms and at the times that they are needed. Surprisingly, almost no literature has explored whether this is possible. Wildly optimistic and highly challengeable claims are often encountered. “Hydrogen is abundant. All we need is water.”1 “It is estimated that renewable energy has the potential of meeting the energy demand of the human race well into the future.” (Lewis, 2003). “ … existing renewable energy resources are capable of substituting for coal-fired power stations…” (Diesendorf, 2005, p. 1). “Renewable energy and energy efficiency can deliver the power we need, without the problems.” (ACF, 2005). “ … energy crops can provide ample biofuel feedstock.” (Lovins, et al., 2005, p. 107). “All observers of energy seem to agree that various energy alternatives are virtually inexhaustible.” (Gordon, 1981, p. 109). “An entirely renewable and thus sustainable electricity supply is possible using existing technologies.” (Czisch, 2004). “Solar energy can replace fossil and nuclear fuels over the next 50 years thus creating a truly sustainable energy supply system.” (Blakers, 2003).
Unfortunately in the task of assessing the validity of this dominant assumption we have not been helped by the people who know most about the field, the renewable energy experts. They have a strong interest in boosting the potential of their pet technology and in not drawing attention to its weaknesses, difficulties and limits. Exaggerated, misleading, questionable and demonstrably false claims are often encountered in the promotional literature. Minor technical advances which might or might not become significant in the long run are announced as miraculous solutions. Doubts regarding the potential of renewable technologies are rarely if ever heard from within these fields.
This enthusiasm is understandable in view of the need to attract public support and research funding, but it means that contributions by those most familiar with these fields to the critical assessment of the potential and limits of renewables are quite rare. In developing the following review, considerable difficulty has been encountered from people hostile to having attention drawn to the weaknesses in their technologies and proposals (including threats of legal action if data they have provided in personal communications is used). Sources eager to provide information tend to dry up when they realise that limits are being explored. In addition some of the crucial information will not be made public by the private firms developing the new systems. For example it is almost impossible to get information on actual windmill output in relation to mean wind speeds at generating sites. Where commercial interest might be threatened by critical inquiry, prickly reactions, including harassment, can be encountered.
Unfortunately these difficulties have meant that at times it has not been possible to get access to information that would settle an issue and that must exist somewhere, and that at times one has to attempt an indirect estimation using whatever scraps of information one has been able to find. Ideally this study would have been carried out by someone more expert in renewable energy technology than I am, but it is understandable that the task has been left for an outsider to take up.
This is not an exhaustive examination of all the various renewable energy sources but it attempts to be a sufficient analysis, i. e., to deal well enough with the crucial issues which seem to enable a persuasive case. A number of technologies which might make a significant difference some day have not been examined closely because there are not persuasive reasons to think they can rival the main four options, wind, solar thermal, photovoltaics and biomass.
