bobmcgee

“Fortune,” said Don Quixote to his squire, as soon as he had seen them, “is arranging matters for us better than we could have hoped. Look there, friend Sancho Panza, where thirty or more monstrous giants rise up, all of whom I mean to engage in battle and slay, and with whose spoils we shall begin to make our fortunes. For this is righteous warfare, and it is God’s good service to sweep so evil a breed from off the face of the earth.“

Australia’s Renewable Energy Target has been in the news this week. To the forces of one side of the climate war any change would be an attack on clean energy. To the other side the RET is a cursed impost on consumers and manufacturers that is reducing our standard of living by pushing up energy costs. It is not disputed by either side that the clean stuff can only compete with the dirty stuff if government tilts the playing field by means of regulation and subsidies.

Energy is a fundamental requirement of life. Animals must eat. In fact animals must eat the primary production of plants. A typical terrestrial food chain is three-tiered, eg grass, rabbit, fox. Longer chains are possible eg algae, zooplankton, copepod, little fish, big fish, seal, shark. At each step up the chain there is a reduction of very approximately 90% in biomass. If there is less than about ten times as much prey than predator food is hard to catch. If food requires more energy to catch than the energy it yields the predator starves. It is a biological reality that energy returned must be greater than energy invested (variously abbreviated EROI – energy returned on investment, or EROEI – energy returned on energy invested). And it explains why big fierce animals are rare.

Prior to the industrial revolution most people had to make do with the power of their own bodies plus the odd draught animal. The rich and powerful could put others to work on their behalf and parasitise their labours. Cheap energy makes us all rich and powerful. Buckminster Fuller went to the trouble of converting the energy being put to work in the world to its equivalent in slaves. In 1950, every human on earth had the equivalent of 38 full-time slaves. It would be more now. Our capacity to grow and distribute food, educate our community, enjoy manufactured goods and fight off the barbarians who would like to behead us depends on the availability of enough energy.

There is a fear upon the land that carbon dioxide, essential to that very first step in the food chain, photosynthesis, is a pollutant and will cause us to fry. There have been a number of initiatives aimed at reducing the human output of carbon dioxide. It would be reasonable to expect that such initiatives would reduce the output of CO2 but that doesn’t seem to be essential to their adoption. Burning biomass for example produces more CO2 per unit of energy than does coal or gas but enjoys the blessing of the EU. And then there is wind …

A slight breeze at this moment sprang up, and the great vanes began to move.

“Though ye flourish more arms than the giant Briareus  ye have to reckon with me!” exclaimed Don Quixote, when he saw this.

And of course he said his prayers, lowered his lance and charged.

A slight breeze can spring up at any moment or die away. It means that wind is of little value for base load power. The fossil fuel power station can’t be turned off and on willy nilly so when the wind blows the impact on coal or gas usage is small and the CO2 output is little diminished.

The answer, my friend, is storage. Why don’t we build a very large battery?

Which brings us back to EROEI.

A plant that only generates as much energy as it took to build it has an EROEI of 1 (and had better be pretty). Weißbach et al. investigated the figures for a variety of energy sources and compared them with their estimate of the EROEI required to maintain civilisation at a standard comparable with the US or Germany which is about 7.

 

Energy Returned on Energy Invested, derived from Weißbach et al.,with and without energy storage (buffering).  CCGT is closed-cycle gas turbine.  PWR is a Pressurized Water (conventional nuclear) Reactor.  Energy sources must exceed the “economic threshold”, of about 7, to yield the surplus energy required to support an OECD level society.

You can see from the graph that our conventional power plants have an EROEI of 30. Energy is stored simply by storing coal. We set one slave to work, in return we get the output of thirty slaves. Good value. Civilisation flourishes.

Wind performs quite well at 16. Civilisation can flourish whenever the wind blows.

If you would like power when the wind isn’t blowing we must have some storage. The cheapest form of storage is to pump water uphill when the wind blows and generate hydroelecticity when you need it. This is practicable where the terrain permits. This drops the EROEI to 3.9 …  civilisation collapses, we are all beheaded. Any form of battery or chemical storage requires the investment of at least 10 times more energy … you would be better off putting real slaves in a treadmill.

The bird mincers, therefore, are good for only a small proportion of electricity production. Photovoltaic solar and biomass will not cut it. At all. Full stop. In a competitive market no-one would invest money in those technologies. The redirection of taxes or the imposition of regulation to foster these technologies is truly corporate welfare. The Solar Generators that concentrate the sun’s rays on a central boiler or any passing bird or insect by reflection scrape above the line but at a cost to the environment that should be unacceptable. Their EROEI would be somewhere between 19 and 9 unless you shut civilisation down every night.

The population that we have on earth today cannot be sustained without cheap energy. Famine is the result of political failure. If we cannot produce the energy required to grow and distribute food in a stable society there will be war.

Hydro power has an excellent EROEI but requires a particular combination of water and terrain. More of it would be good but in the long run the true solution is inescapable. We will embrace nuclear power or leave the earth to the cockroach.

Sources …

Weißbach et al.

The catch 22 of energy storage. John Morgan.