Monday, 21 March 2011

Rethinking Energy

A coal-fired power station at Ironbridge in Shropshire.






There have been two stories with the potential to influence global energy policy in the international news in recent weeks.

The tragic events in Japan have raised important questions about the future of nuclear power. To some extent the debate on nuclear energy is a permanent feature of our lives, and peoples’ views tend to reflect their politics. People on the left tend to be against nuclear energy; those on the right tend to favour it. Those who oppose it point out the dangers of nuclear accidents, and the problems of dealing with nuclear waste. Those who favour it see it as cheap, and a solution to the problem of global warming and/or dwindling fossil fuel reserves (curiously the strongest proponents may deny both global warming and the potential for oil to run out).

Events at Fukushima in the last week have graphically brought the dangers of nuclear energy into the public eye for the first time since the Chernobyl disaster in 1986.

Nuclear fission reactors work roughly like this (and I admit this is a bit simplified): Nuclear fission occurs when atoms split into smaller atoms. For most atoms this is a pretty rare event, but some isotopes of atoms do this rather more frequently.

All elements have different isotopes; atoms have two forms of subatomic particles in their nucleuses, protons and neutrons. Protons have a positive charge; the number of protons in the nucleus matches the number of (negatively charged) electrons in the shell. This in turn effects the chemical properties of the atom, thus atoms with the same number of protons are considered to belong to the same element; they will form the same compounds and take part in the same reactions. Neutrons do not alter the chemical properties of atoms, so atoms with different numbers of neutrons can belong to the same element. However neutrons are not without any effect, they have mass, and therefore alter the mass of any molecule they form. Atoms with the same number of protons, but different number of neutrons are referred to as being different isotopes of the same element.

Normally this doesn’t make much difference. Some isotopes behave slightly differentially in nature, and will be preferentially incorporated into rocks as a result. For example when carbon dioxide is dissolved in water, molecules with lighter forms of carbon will escape into the atmosphere more readily. Thus water at higher temperatures will contain more light carbon than heavy carbon, whereas water at lower temperatures will have a more even balance. This is of interest to geologists, since this isotope ratio will be reflected in any calcium carbonate (limestone & shells) formed in the water, but has few practical applications in day-to-day life.

However this is not the end of the story. Some isotopes are less stable than others they will break down into other elements quite rapidly, ejecting neutrons and protons and giving off gamma radiation and heat (gamma radiation is a form of electromagnetic radiation). Heavier elements tend to have more unstable isotopes – no element heavier than uranium has any stable isotopes at all.

Gamma radiation is harmful, but on the whole this is not something to worry about. You probably wouldn’t want to set up home in a uranium mine, but most of us are exposed to more gamma radiation from the breakdown of carbon within our own bodies than from all external sources combined.

However if you get enough unstable material and lump it together then something interesting happens. The protons and neutrons given off by nuclear fission will collide with other unstable atoms, causing them to break down too; this is called a chain reaction, and leads to considerable heat being given off.

It is this heat that is used in nuclear reactors; water is pumped over uranium or plutonium fuel, and heated to become steam which then drives a turbine, in the same way as steam produced by heating water with a coal fire.

There are three problems with this sort of reactor. Firstly the fuel is by its nature rather expensive. Since uranium will undergo a chain reaction if it becomes too concentrated, all uranium ores are fairly dilute (there is evidence that a uranium ore load was concentrated by geological processes to the point where it did undergo a chain reaction about 1.7 billion years ago at Oklo in modern Gabon). The most concentrated (known) ores contain about 3kg of uranium per tonne of ore. Unfortunately not all of this is made up of isotopes that undergo fission at a high enough rates to be useful as fuel, so a tonne of uranium ore will only produce 579g of usable material, although this will yield the same amount of energy as 69,500 tonnes of coal. This does not include the overburden (material above the ore, which has to be removed or tunnelled under to access the ore) for either the uranium ore or coal. Uranium is generally leached from the ore using sulphuric acid, so uranium mine tend to be unpopular neighbours.

Uranium is a finite resource. 50,772 tonnes of uranium was mined in 2009 (up from 44,853 in 2008), enough to meet 76% of world demand. There are 5,469,000 tonnes of known recoverable uranium worldwide, and it is likely that some (though not a great deal) more will be found. So if we go on extracting uranium at the current rate it will last us for about a hundred years. Unfortunately to do this we would not only have to refrain from building any more nuclear reactors, we would have to cut the output of the current reactors by 24%. This seems unlikely in the current political climate, with 60 nuclear reactors currently under construction globally, and more planned.

Occasionally stories appear on the Internet about the possibility of extracting uranium from seawater. Seawater contains ~3 milligrams of uranium per tonne of water and in theory this could be extracted. However this means it would be necessary to process 333 tonnes of seawater to gain 1g of uranium, which would then yield the same energy as 69.5kg of coal, so a pretty efficient means of extracting the uranium would need to be found for this to become viable. This probably tells us more about the Internet than the future of nuclear power generation.

The second problem with nuclear fission reactors is the production of waste. This comes in two basic forms; spent fuel, uranium and lead (the end product if the fission of uranium) that no longer gives off sufficient radioactivity to be useful as a fuel, but which is still fairly radioactive (to some extent this can be re-refined, but this is not an endless process) and other material that has become irradiated during the fission process. All nuclear waste needs to be stored safely until it has ceased to become radioactive. Since this can be tens or even hundreds of thousands of years the subject of how to do this remains highly controversial.

The third problem with fission reactors, and the one most pertinent to the ongoing crisis in Fukushima, is that reactors cannot simply be turned off. Under ideal circumstances reactors that have reached the end of their lives undergo a lengthy process of decommissioning, in which the spent fuel and anything else that has become irradiated (typically the whole reactor) are removed and stored at a waste disposal facility.

In the case of Fukushima (and Chernobyl) the where the process of cooling the reactor is interrupted the situation is far more serious, as heat can build up and lead to fires and/or explosions. This is not the same as the nuclear explosions caused by nuclear bombs, in which a large amount of fissile material is brought together rapidly to cause a runaway chain reaction which directly causes the explosion, but rather the direct result of to much heat building up in an enclosed, pressurised container, the equivalent to throwing an aerosol canister onto a bonfire. However it does have the potential to scatter radioactive material over a large area, similar to the ‘dirty bomb’ explosions worried about by counter-terrorism types.

All of this has caused people across the globe to question the future of nuclear fission reactors. Professor Benjamin K. Sovacool of the Lee Kuan Yew School of Public Policy, National University of Singapore (a long-term opponent of the nuclear industry) has pointed out that the nuclear industry has caused more fatalities since 1986 (i.e. after Chernobyl) than the aviation industry has managed since 1982 (excluding acts of war and terrorism), and that it manages to cause more fatalities per year than any other form of generation than hydro-electric, as well as causing around $330 million in damage. International organisations Such as Friends of the Earth and the World Development Organisation have stepped up their campaigns against the nuclear industry, local campaigns against nuclear power have stepped up their activities across the globe and there have been scares about fallout from Fukushima reaching China and the US.

Ultimately the fate of the Fukushima Plant is likely to influence the future of the nuclear industry across the globe. The nuclear industry has a long track record of vigorous lobbying, which has served it well for most of the time. However this has tended to deepen the division in opinion on the subject; people tend to be either strongly pro- or strongly anti-nuclear.

Should events in Japan lead to a large number of fatalities then it is likely that opinion would swing strongly against the nuclear industry, and that it would become almost impossible for politicians to justify new nuclear projects. Already the UK government, generally bullish about nuclear power, has announced that it will be suspending eight proposed nuclear power stations until the situation in Japan becomes clearer, and Germany has announced it will be suspending operations at all nuclear plants over 30 years old.

However if there is a more positive outcome in Japan it is likely that the nuclear industry could recover. Tsunamis are rare events, even in the Pacific, in the Atlantic no tsunami has been experienced in living memory. It is therefore easy to dismiss the dangers of a similar incident occurring in Western Europe or the Eastern United States. However they are not unheard of, and nuclear facilities are often located in coastal areas, as they need plenty of water.

The Lisbon Earthquake of 1755 caused a tsunami that hit parts of southern England, in 1607 an underwater landslip in the Irish Sea caused a tsunami in the Bristol Channel, the ancient Minoan civilisation on Crete was extinguished by a tsunami caused by the Santorini Volcano in about 1600BC and the North Sea coasts of England, Scotland, Denmark and the Netherlands were scoured by a tsunami in ~6100BC caused by an underwater landslide off the coast of Norway. It is theorised that a volcanic eruption or landslide in La Palma in the Canaries could trigger tsunamis with the potential to hit the coasts of North America or Western Europe causing widespread devastation.

The second story to dominate the international media this year has been the waves of pro-democracy demonstrations sweeping across the Middle East. These began in Tunisia where demonstrations provoked by the suicide of student Mohamed Bouazizi brought down the government of President Zine El Abidine Ben Ali in 28 days. This inspired a similar wave of protests in Egypt, where the 30-year reign of President Hosni Mubarak came to an end when soldiers refused to open fire on the demonstrators. From here protests and uprisings spread across the Middle East, and things got complicated.

British, French and American armed forces are currently being deployed in the air above Libya, supporting an uprising which briefly took control of much of the country, but which has subsequently been crushed by troops loyal to the Libyan leader Colonel Muammar Gaddafi. The Libyan government has managed to alienate its few overseas allies, and the western powers, whose own populations are prone to supporting pro-democracy movements, are happy to be seen to be supporting the rebels.

However while the west is keen to support pro-democracy activists in Libya, there has been rather less support for protesters elsewhere in the Middle East. Protests have met with brutal responses in Morocco, Mauritania, Saudi Arabia, Yemen, Oman, Syria and Bahrain (where additional troops and police were brought in from Saudi Arabia and the United Arab Emirates to suppress demonstrators).
Across the Middle East the suppression of democracy has been justified by the fear of religious extremism, but it does not take a great deal of cynicism to conclude that oil also plays a major part in this story.

Oil is the world’s favourite fuel. Much of the world’s electricity is generated using oil, and almost all of our cars, ships and aircraft run on it. Like uranium oil is a limited resource, and most of it is in the Middle East. The greatest known oil reserves (i.e. oil known to be still in the ground) are in Saudi Arabia, the second greatest in Iraq (though this has turned out to be rather less than was hoped). Iran, Kuwait, the United Arab Emirates and Libya are all in the top ten of known oil reserves.

The world currently uses about 31 billion barrels of oil a year. Known oil reserves, globally, are about 1333 billion barrels, or enough for about 45 years if consumption does not increase (which it is rapidly doing). Like nuclear energy, oil is prone to problems. The Gulf Oil Spill of 2010, caused when a hurricane hit the Deepwater Horizon oil-rig in the Gulf of Mexico, released 205 million gallons of crude oil into the environment, with a total economic cost somewhere in excess of US$6 billion.

Demand for oil is growing across the world as economies develop, and resources are beginning to get low. The term ‘Peak Oil’ is used to refer to the point at which half the world’s oil will have been used. This does not imply that oil will last as long after peak oil as it did before, since oil consumption keeps rising. Rather the assumption is that once Peak Oil is passed then we will start to have problems. Exactly when we will pass Peak Oil is disputed, but it is generally assumed to be before 2020.

As oil becomes scarcer oil companies are willing to look for oil in less accessible place, such as the Arctic or deep ocean sites, and are exploring controversial oil sources. Oil shale’s are oil sources that need to by physically dug up and worked like metal ores; this process is low yield and highly polluting. Biofuels are oil products extracted from plants grown commercially, either on land that would otherwise have grown foodcrops, or on cleared sites that previously had rainforest cover; like nuclear fuel these biofuels are often promoted as being ‘clean’. Some countries have even taken to catching deepwater fish as a source of oil; such fish are long-lived and breed slowly, so catching them in this way is in no way sustainable – they are effectively being mined.

Ultimately the world needs to find ways to reduce its fuel consumption (not easy with a rising population) and to find new ways to generate power. Oil is particularly troublesome, as we have no idea how to replace some of its functions; notably in the manufacture of plastics and aviation fuel. Realistically the world probably can stop making ‘disposable’ products from plastic, but the only solution to a shortage of aviation fuel will be to fly less.

It is quite likely that the age of the motorcar will come to an end. It is possible to build cars that run on electricity rather than oil, but this electricity will need to be generated somehow. While the car is unlikely to disappear completely, mass ownership of cars is likely to disappear; cars are likely to become a luxury item. This can have two possible effects. Either we could return to a situation where much of the population does not travel much, or we need to invest in reliable, pleasant and cheap public transport.

Governments need to play a greater role in planning for our future energy needs than is currently fashionable. Relying on market forces is likely to steer us into a brick wall sooner or later. Power companies motivated purely by profit are unlikely to be stirred by environmental concerns, indeed the industry is gaining a reputation for bad corporate citizenship in a number of areas, from poor customer service to cartel-style price fixing.

As well as actively planning how power will be generated in the future, and laying the foundations for a post oil transport network, governments can do more to empower citizens to plan for the future. Housing is currently seen as a form of wealth more than as homes for the population. Owning property and gaining income from rent is seen as a virtuous thing to do. Leaving aside the fact that this discourages investment in more productive forms of wealth generation (i.e. making things and employing people), this tends to discourage investment in improving homes. An owner-occupier can invest in insulating his home, or even generating some of his own power through solar panels or wind turbines and hope to see a return on his investment. A tenant doing the same could see his rent increased with the value of his home, or even face legal action from his landlord for altering the property. Similarly the landlord has little incentive to invest in his property if he just sees it as a source of rent and does not pay the fuel bills.

These modern houses have been built with solar panels.













Older houses such as this one need to have them fitted.







Ultimately countries and businesses that want to remain competitive will need energy sources that do not run out, cause problems that shut down other sections of the economy for periods of time, or drive up the cost of living (no matter how much our leaders might dream, a worker who struggles barefoot through the snow to work a fifteen hour shift in return for a crust of bread probably won't achieve very much useful work). Our current favored methods of energy production, oil and nuclear, do not meat any of these criteria, so if we want to succeed as nations and economies we need to think about how to replace them.

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