This post-of-two-halves has been inspired by this post and this one, which the post I linked to first was also inspired by. So, why do people say the blogosphere’s nothing more than a great big circle-jerk again? Although, if this was a circle-jerk, I would be a very late comer. As it were. Ahem…
Anyway, as I understand it, the peak oil argument runs something like this:
Oil is a finite resource. At some point, therefore, oil supplies will fail completely. Before this happens, our ability to extract oil in ever-increasing volumes will come to an end. Passing beyond this moment of peak oil production will on its own be enough to start to choke off the happy economic expansion we’ve been living though for the last hundred-ish years. Then, as the supply starts actually to decline, terrible wars will break out amongst nations desperate to get their hands on oil resources. The effects of these wars, and the worsening oil shortages, will cause whole sectors of the global economy to shut down, which will in turn mean that essential services will become unavailable. This will lead to a fracturing of society and a dog-eat-dog mentality among those humans lucky enough to survive, who will eek out their lives in a violent, post-apocalyptic wasteland. (It should be pointed out that not everybody believes in the whole thing – some people are on-board for the choking off of economic growth, for example, but not the full-blown apocalypse.)
It’s a really weird thing. Usually my capacity for getting freaked out by portents of imminent doom is almost infinite, but this one doesn’t bother me in the slightest. I think it’s because the whole concept has always seemed like ludicrous scaremongering to me, even when my biology teacher tried to scare me with it 25 years ago. (She also tried to scare us with apocalyptic fantasies about AIDS. She was into apocalypses, or possibly just frightening kids, in a big way.) Anyway, the remainder of this post, and the next one, will be made up of what I see as the counter-arguments, and I offer them in the hope they might reassure other people too. (Oh, and for the record, I’m not a geologist, or a physicist, or a chemist, or an economist, or any other kind of -ist. What follows are the thoughts of a reasonably well-informed (I hope…) layman, and should be treated with the appropriate level of scepticism.)
Firstly, at the risk of stating the obvious, oil is not a source of energy in its own right. Oil is a very convenient means of storing and transporting energy, but no energy is or ever has been produced by oil. The source of the energy stored in oil is the sun. When there are problems with accessing energy from oil, therefore, the obvious solution to the problem is to access the source directly.
One of the arguments I have heard is that fossil fuels represent millions of years of stored sunlight. This is undeniably true, but it’s only a partial truth. Plants are not an especially efficient store of energy. Most of the energy captured by photosynthesis is used to enable the chemical processes taking place in the plant; comparatively little is stored in its structure. While the fossil fuels, including oil, that result from plants do contain energy collected from sunlight over millions of years, they contain only a tiny fraction of the total energy received from the sun over that time.
The amount of energy that reaches Earth from the sun is truly stupendous. Global energy usage in 2005 was 500 exajoules (500 x 1018 joules), itself a pretty big number, but total available solar energy is 3,800,000 exajoules per year. This means that we would have had to capture less than 0.014% of available solar energy to supply total energy needs in 2005. But, if we were only trying to replace oil (which supplied 180 exajoules in 2005), we would have needed to capture less than 0.005% of available solar energy.
Capturing energy from the sun is difficult, but it’s not as difficult as many people assume. This is partly because most people, when they hear of solar energy, think in terms of photovoltaic cells, which capture and convert to electricity a fraction of the light energy arriving from the sun. A lot of the energy from the sun arrives in the form of heat, though, and accessing this energy is relatively straightforward, as anyone who’s used a magnifying glass to set fire to something will know. (Important note! Aethelread does not encourage setting fire to things in this way! You shouldn’t accept sweets from strangers, either. Oh, and always use the Green Cross Code…)
Mirrors can be used to collect and focus the heat energy of the sun, which can then be used in a number of ways. Firstly, it can be used directly for any industrial or domestic purpose that requires heat – solar furnaces can achieve temperatures of 3,000°C, which is more than sufficient to melt steel, for example. Secondly, the heat can also be used to produce mechanical and electrical energy, most obviously by means of a Stirling engine.
The Stirling engine was first developed in 1816 as an alternative to the steam engine, and has been in almost continuous (but low-profile) use ever since. A Stirling engine uses the heat of the sun to heat a volume of gas in a cylinder. The heating causes the gas to expand, and the expanding gas then pushes a piston up the cylinder. (Expanding gases also operate the pistons in both steam and internal combustion engines.) The mechanical movement that results from this can be used either directly to drive machinery, or can be used to turn a turbine, thus producing electricity. The important thing to recognise here is that this is not a pipe-dream – solar thermal power plants using Stirling engines and other technologies already exist, principally in Spain and the United States.
I have heard the argument that solar power is impractical, because there are large parts of the planet, including many of the most developed areas, that do not receive sufficient sun to generate their own power. This is undeniably true, but it’s also true that there are unoccupied areas of the planet – such as deserts for example – that receive a very great deal of sunlight. If solar energy were to become of central importance in replacing oil, there would clearly need to be a global distribution network to transfer power from energy-rich areas to other areas that are energy-poor. Those who argue such a network would be impractical might like to consider that oil is similarly dependant on a global distribution network.
In any case, the need for such a network will be reduced, as there are plenty of other sources of energy. One obvious one is the wind, which exists in less stupendous quantities than solar energy, but is still, on its own, enough to replace all existing forms of energy several times over. Global commercially viable wind energy has been estimated at 2400 exajoules per year.* In order to replace all existing sources of energy in 2005, therefore, it would have been necessary to capture less than 21% of commercially available wind energy. If we were only interested in replacing oil we would have had to capture just 7.5% of the available wind energy. As with solar energy solutions, it’s worth noting that capturing wind energy isn’t a pipe-dream – the technology already exists, and has already been proven to work.
There are still disadvantages with these sources of energy, of course, most notably that they are not continuously available – solar energy is only available when the sun is shining, and wind energy when the wind is blowing. The obvious difficulties with continuity of supply can be addressed in two ways. Firstly, by over-production at times when energy is available, with the resulting surplus being stored for times when the supply fails. Secondly, other more reliable methods of energy production, such as nuclear energy and tidal energy, can be used to cover the gaps. If we are only concerned with replacing oil and not all fossil fuels, coal would also be available as an alternate energy source.
The upshot of all of this, I hope, has been to make it obvious that we are not facing an energy-supply crisis. On their own, the renewable energy sources (solar, wind, tidal, wave, geothermal) offer an amount of energy spectacularly in excess of what we need, or are ever likely to need. It might, though, be possible to argue that we face a crisis in the availability of energy in usable forms. Isn’t it the case that I’ve talked mainly as though electricity is the only form of power we need, when electricity is useless in lots of contexts?
To find out my answer to this and other questions, some of them even less interesting, stay tuned for part two…
* – the figure in the source is given as 72 terawatts, but for ease of comparison I have made a very approximate conversion to exajoules.