BraveNewClimate

Guest Post by Martin Nicholson. Martin studied mathematics, engineering and electrical sciences at Cambridge University in the UK and graduated with a Masters degree in 1974. He has spent most of his working life as business owner and chief executive of a number of information technology companies in Australia. He has a strong interest in business and public affairs and is a keen observer of the climate change debate and the impact on energy. He is author of Energy in a Changing Climate, as well as an upcoming book on sustainable energy systems, and is the lead author of the 2011 paper in the journal Energy “How carbon pricing changes the relative competitiveness of low-carbon baseload generating technologies“. He wrote a popular post last year on BNC entitled: Cutting Australia’s carbon abatement costs with nuclear power

This post, and the previous one, provides an insight into Martin’s new book: The Power Makers’ Challenge: and the need for Fission Energy

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PART 2

Fission Energy

The big difference between a coal and fission energy is that coal is combusted (that is, burned in a chemical reaction with oxygen) to boil the water, whereas fission relies on a nuclear reaction by splitting uranium atoms to generate heat.

Fig. G.2 Fission Energy. From US Energy Information Administration (2008)

The most common type of nuclear fission reactors are thermal reactors called ‘light-water’ reactors (LWR). Thermal reactors were first used commercially to generate electricity in the late 1950s and there are now over 400 thermal reactors installed in more than 30 countries world-wide. Together they generate about 16% of the world’s electricity. France is one of the largest users of fission energy and gets almost 80% of its electricity from its 59 nuclear power stations.

Fig.G.1 Nuclear Power Plant. From Lange P (2009)

Both coal and fission reactor plants use fuels mined from the earth. A big difference is in the amounts of fuel. A 1,000 MW coal power station needs about 3 to 4 million tonnes of coal a year. A 1,000 MW fission reactor plant accounts for only about 150 to 200 tonnes of natural uranium a year. Less fuel used means less fuel to store and less waste. No huge coal storage areas and waste slag heaps containing toxic metals like arsenic and lead are needed for fission reactor plants, and there is no need for thousands of kilometres of coal freight trains.

Fission reactor fuel is significantly less expensive than coal per unit of energy generated. Fuel in a fission plant makes up about 5-10% of the cost of running the plant. For a coal plant that can be 30-60%. Fission energy is 30% cheaper than the least expensive CCS solution and less than half the cost of solar thermal.

Fig. G.3 Nuclear Fuel Cycles. From Chang Y (2010) 

Coal and fission are both improving their efficiency in process technology. However light-water reactors use less than 1% of the energy in the natural uranium while coal plants use closer to 40% of the energy in the coal. Thus there is substantially greater scope for efficiency improvement with fission than fossil fuels. There are no physical impediments to extracting practically all the energy in the natural uranium by recycling the used fuel. Fission energy has the unique advantage of using a fuel with an energy density millions of times greater than any other known energy source.

Fission energy was a massive breakthrough in 1951, yet it has only been exploited to a fraction of its potential. Since those early days of ‘atomic’ energy, as it used to be called, it has steadily expanded despite some heavy setbacks in the 1980s. Unlike other energy sources, it is on the brink of improving its efficiency 100 fold. This is unlikely to be possible for any existing renewable energy resources or fossil fuels. So why do many in the community still resist using it?

 Nuclear safety

Those who are cautious about nuclear power often quote safety as their major concern. This concern usually involve the safety of the reactors, the safe storage of the waste, and the risk that somehow the nuclear fuel used in the reactor will finish up in a nuclear weapon of some kind.

One objective way to assess the safety of a technology is to look at its history. Fortunately with fission reactors we now have quite a bit of history to draw on. In 50 years there have been just three significant accidents at commercial power stations, and only one (at Chernobyl) created a serious radiation hazard to the public. The official World Health Organisation death toll from that accident and its long-term aftermath remains at less than 100 individuals.

Tragic as industrial accident deaths are, in order to make a proper comparison with other energy technologies we really have to look at the number of deaths from other energy sources, particularly coal, hydro and gas. Thousands have died in coal mines and hydro dam accidents. The relatively low number of deaths from one nuclear accident after 12,700 reactor-years of civil operation attests to nuclear’s relative safety.

In terms of nuclear waste safety, the volume of waste is not really the issue – it is about one ten thousandth of the coal ash waste from a coal plant. The real issue is where to store the long-lived nuclear waste safely. Most of the waste produced in power plants over the last 50 years has been held close to the reactor site. Sometimes some of it is reprocessed but that doesn’t significantly reduce the waste problem. Eventually, some of it will need to find a permanent and secure home. Current plans are to bury it deep underground in safe repositories. But, unlike the coal ash, not all (indeed, hardly any) of the energy has been removed from the spent fuel and this can be recovered in fast reactors. This ‘waste’ is actually a fuel store for our grandchildren and their grandchildren. The ‘permanent’ storage may not need to be that permanent.

For a rogue nation or terrorist group wanting to make a nuclear weapon, using reactor fuel and waste from civil power plants is not a great place to start. Converting reactor-grade material to the weapons-grade needed for bomb making is difficult and expensive and would be readily detected. It would be cheaper and easier to buy or steal weapons-grade material from one of the nations who already have it. It seems unlikely that access to a genuine civil reactor would increase the risk of proliferation. Those nations hell bent on developing nuclear weapons will do so with or without fission energy. The inconvenient truth is that banning nuclear power will neither reduce the risk of proliferation nor the risk of terrorism.

All industrial processes, including fission energy, have dangers. The evidence suggests the dangers to health from fission energy are significantly less than the dangers from mining fossil fuels and breathing the pollution created during converting the fuel into energy – either in a power plant, or in a motor vehicle. If we walk away from fission energy, as advocated by some environmentalists, we will continue to burn fossil fuels, which the evidence says is not only more dangerous to our health and safety but a much greater threat to the climate.

Nuclear Myths

Myths seem to surround fission energy. Nuclear power attracts a great deal of flack, probably because of the fearful association with nuclear weapons and the damage they have done to innocent people. If we are to tackle climate change in a realistic way, we need to get over these irrational fears. Tackling climate change means moving away from fossil fuels over the next few decades. In most countries, fission energy will be the only way to do this without impacting the reliability of their electricity network.

The first of the most common nuclear myths is that renewables make nuclear unnecessary. In many ways this is one of the most dangerous myths because it can seem so seductive and puts false hope in the minds of the public and politicians that somehow, one day, we can replace all that dirty coal with nice clean renewable energy. Earlier I argued that no scalable renewable source is capable of replacing coal throughout much of the world without some technology breakthrough – probably in energy storage. Investing in fission energy would immediately eliminate the need to build new fossil-fuel plants and allow the old ones to be progressively closed. This will have a much greater impact on climate change than building wind and solar plants that rely on fossil fuel plants for backup.

The second myth is nuclear energy is too expensive. Fission plants are expensive to build but cheap to operate compared to fossil fuel plants. Once a fission plant has been operating for a number of years, and the initial construction cost has been fully recovered, the operating cost of the plant per unit of energy produced is lower than for fossil fuel plants and many renewable energy plants. The cost comparison between energy sources has to be based on the full life-cycle cost and total energy produced. Nuclear is the cheapest low-carbon baseload energy source once an adequate carbon price is applied to fossil fuel plants.

The third myth is that nuclear plants couldn’t be built in time. It’s true that fission plants take a number of years to build. We need to urgently move to low-carbon electricity sources so the argument goes that building new nuclear plants will take too long. But what’s the alternative? Wind power and biomass can’t replace the coal plants and no one seems to want more hydro plants. Even if they did the hydro plants also take a long time to build. The only viable low-carbon, renewable alternative that might be scalable to replace coal plants is solar thermal with heat storage. But these plants will also need to be huge. They require 8 times as much concrete and 13 times as much steel as nuclear plants for each GWh generated. If we can’t build the fission plants in time then we surely can’t build the solar thermal plants in time either.

The fourth myth is uranium supplies are not sustainable. Certainly fossil fuels are not sustainable long term but uranium and some other fission energy fuels like thorium are very different to fossil fuels. As discussed earlier, current thermal reactors uses less than 1% of the uranium’s energy potential. Uranium is so cheap today that we don’t bother to try and recover the other 99%. It becomes part of the infamous nuclear “waste”. With reprocessing and fast reactors we can release nearly all the energy from the mined uranium or thorium which will extend the known mined reserves to tens of thousands of years.

The last nuclear common myth we will consider here is that all radiation is dangerous. Some would even argue that radiation and radioactivity are unnatural even though soil, water, the air we breathe and even our own bodies are all naturally radioactive. Radiation can indeed be dangerous in high doses. That’s why medical procedures involving radioactive materials are conducted with great care. The same is true in a fission energy plant. High safety standards and procedures ensure that the public and the plant operators are not exposed to dangerous levels of radiation. The safety history of nuclear power plants over the last 50 years is evidence of this.

The Melting Pot of Options and Opinions

As the pressure increases to reduce GHG emissions from electricity generation, I believe there will be an accelerated push to replace baseload coal and gas plants with fission plants because they are the most cost effective low-emission baseload option. But fission cannot run the whole network.

Electricity supply must match the load, moment by moment, and the Power Makers need flexible generators to follow this load during peaks. They also need generators that can be started quickly when needed (standing reserve). Fission plants can do some of this but, like coal, they take some time to get going from a cold start so cannot be started quickly if suddenly needed to meet a jump in demand. Quick start gas plants in some form will probably still be needed for many years to come.

Fig. 19.1 Electricity Load Curve

Some hope that with more demand management, where the system takes greater control over when power is used, it may be possible to smooth out the load variation and reduce the peaks. This might ease the Power Makers’ job of servicing the variable load. There are clearly electricity demands like recharging of electric vehicle batteries that can be time shifted, but it is hard to imagine a time when electricity demand will stay constant throughout the day and night. Load variation won’t be eliminated.

Others see distributed generation using a number of smaller generators located close to the end-users, with decentralised energy generated at or near the point of use, as the answer to replacing large centralised generators and perhaps eliminating the grid altogether. Cost and reliability of electricity supply will probably sound the death knell for any such concept.

And of course the long promised “smart grid” is often raised as a panacea for the use of variable renewable energy sources in the electricity network. The smart grid vision is to deliver electricity from suppliers to consumers using digital technology to optimise energy savings, energy cost and network reliability. The smart grid could extend all the way from the generator right down to the customer meter and even to end-user devices like air conditioners, pool pumps, clothes driers and refrigerators turning them on and off as needed to balance the demand with supply. Whether the general public will embrace such changes is yet to be tested.

The Future

New technologies for generating electricity may well emerge, and improvements will be made to existing options. Research and development continuously innovates, and we can expect all new technologies will be low-emission. Occasionally there are great breakthroughs (like fission energy) which prove to be game changers, but implementation has been historically slow.

The use of algae, nuclear fusion and innovative storage ideas are all being developed, as is engineered geothermal. Any new electricity technology will be constrained by the nature of its source of energy. Replacing fossil fuels will not be easy – whatever many environmentalists might like to believe. Replacing them with a majority of renewable energy solutions will be very expensive in most countries and may even be impractical. For many countries, relying on more fission energy will not be an option – it will be an absolute necessity.

Technical Appendices

The book contains a number of appendices. These go into much more detail about how electricity networks function and provides greater technical explanations of the individual technologies discussed throughout the book. The appendices are listed below.

A Definition of Terms

B Power Generation and Network Control

C Wind Power

D Solar Power

E Energy Storage

F Carbon Capture and Storage

G Nuclear Power

H Electricity Costs and Markets

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Filed under: Emissions, Nuclear