A modern, prosperous society is predicated on reliable and affordable electricity. The pressing challenges we face with climate change demands we look toward sources of low-carbon energy.
Currently, there are about 450 operating nuclear power plants around the world, that provide 11% of the world’s electricity. Australia has operated two research reactors in suburban Sydney (HIFAR 1958-2007; OPAL since 2007) but has never built a reactor for power-generating purposes. Despite having almost a third of the world’s uranium, a stable geography and 60+ years of nuclear reactor experience, Australia is the only G20 country that explicitly prohibits nuclear power. It was formally prohibited in a few Australian states in the 1980s, and a federal prohibition was later put in place in 1998.
We assert that now is the time for Australia to embrace nuclear power as an integral part of the energy mix and that the prohibition should be immediately overturned.
Nuclear Now Alliance Australia has based this assertion on careful consideration of the arguments for Australia embracing nuclear power, and detailed assessment of the technology, both historical precedent and start of the art. In doing so, we have undertaken a comparative analysis of nuclear power to other energy sources that can meet Australia’s energy demands. This analysis is outlined below, with particular emphasis given to comparison with other low-carbon energy sources. We have endeavoured to provide all key references informing our assessment.
The Energy Trilemma
The fundamental trilemma when it comes to energy generation is choosing sources that ensure the overall system satisfies three important criteria:
The system can provide power at an affordable price
The power is available on demand
It is a non-polluting and low-carbon power generation
How do the different energy sources compare? Coal and natural gas satisfy the first two criteria but are both carbon-intensive. Coal is also heavily polluting, when it burns it releases a number of airborne toxins and pollutants, including mercury, lead, sulphur dioxide, nitrogen oxides and particulates. Carbon mitigation technologies such as carbon-capture and storage continue to be the focus of development but have yet to be demonstrated to be cost effective despite decades of research.
Solar and wind energy satisfy the clean criteria, but are intermittent in nature, so require other technologies to help balance the output to the grid. From a simple levelised cost critique, wind and solar continue to drop in price and have become competitive with the alternatives; however when system costs are included, the economics can change. These costs are a result of the unpredictable and the variable nature of how the electricity is generated.
For a low penetration of variable renewable sources on a grid these costs are reasonably low, but as their presence increases these costs can rise significantly. Adding storage to address the intermittency challenges of solar and wind is a potential solution, but the scale at which this would be required significantly reduces the cost competitiveness of these energy sources.
Hydropower is a source of renewable energy that does not suffer the intermittency problems of wind and solar, however it is heavily dependent on geography and a water source. With many suitable river systems in Australia already dammed, hydropower is not a solution that can be scaled up sufficiently to meet Australia’s energy demand.
Nuclear power is the only scalable energy source that addresses all three criteria. It has, on average, the one of the highest capacity factors of any energy source, has one of the lowest carbon emissions over its lifecycle, and when implemented right, can be a very affordable source of electricity.
Prior to the mastering the challenges of nuclear fission, humans were accustomed to generating electricity from fossil fuels such as coal, which has an energy density of about 24 MJ/kg (megajoules per kilogram). When we learnt to liberate the energy of a uranium atom through nuclear fission, verifying Einstein’s well known equation E=mc2, we entered a new era of harness the vast energy contained in this new fuel.
When considering energy conversion in a typical light water reactor, a single kilogram of natural uranium can produce about 500,000 MJ of energy. If that same kilogram was used in a fast reactor, the energy conversion jumps by a factor of 56, to a staggering 28,000,000 MJ.
The enormous energy density of nuclear fuel, and our ability to liberate this energy safely in a nuclear reactor is what gives nuclear power so many advantages over alternative sources of energy. Figure 2 shows a direct comparison between the energy density of an uranium oxide pellet to the major fossil fuels.
When comparing energy density of nuclear fuel to wind and solar the difference is even more stark. Solar energy is a diffuse energy fundamentally limited by the irradiance from the sun at the surface of the earth. One square metre at the equator corresponds to about 0.001 MJ every second. Similarly, the global average wind kinetic energy per square metre is about 1.5 MJ. What does this mean in real-world electricity generation terms? As shown in the Figure 3 below, assuming a high capacity factor for both wind and solar in Australia, (33% and 27%, respectively), about 11 millions panels, or 939 turbines would be required to produce the same amount of electricity as a 1 GW nuclear power plant.
The challenges that climate change present has led to a strong demand in low-carbon sources of energy. Nuclear power has one of the lowest carbon footprints of any energy source.
During operation, a nuclear power plant releases no carbon dioxide. The only carbon emissions are generated indirectly during energy generation lifecycle. A full lifecycle analysis of the emissions by the Intergovernmental Panel on Climate Change’s Working Group III shows nuclear power has an average carbon footprint of 12 g C02eq/kWh, four times lower than solar PV and comparable to onshore wind. The data from this study is shown in the Figure 4, which compares emissions to other energy sources.
Figure 5 shows great animation from Grant Chalmers shows the carbon intensity of electricity generation of a recent 32 day period for a number of locations, with the blue asterisk showing the mean over that period. Jurisdictions with significantly high penetration of nuclear energy (Sweden; France; Ontario) show a consistently low carbon intensity; whereas those with well know high penetration of renewables (South Australia, Germany, California) show significant variations in emissions, with often high averages over this period.
Decarbonisation of our electricity grid is only part of the challenge. A significant proportion of Australian greenhouse gas emissions are created in other sectors. Along with electricity generation (34%), transportation (19%), stationary energy (18%, which is fuels burnt directly for manufacturing, mining, residential and commercial purposes) and industrial processes (7%) make up a significant proportion of Australia’s greenhouse gas emissions, so any serious discussion on decarbonisation should also include solutions that address these sources. Fortunately, nuclear power has the ability to lower emissions in these sectors too. Transport decarbonisation may come via a transition to electric vehicles, or those powered by hydrogen fuel cells. There is also a possibility of using substitute carbon-neutral fuels such as methanol or dimethyl ether as direct alternatives to petrol or diesel. In all cases, nuclear power has a role providing low-carbon electricity, or process heat to decarbonise the industrial processes required to produce hydrogen or synthetic fuels.
Process heat applications of nuclear power have been a very active area of research in recent times. Low temperature processes such as fresh water desalination have been well-established with current nuclear reactor designs in Japan, India and Kazakhstan; while high-temperature reactor designs (that can produce output temperatures of up to 900°C) will drive the development of lower carbon footprint industries.
Resource and land conservation
Resource and land conservation should play an important role in deciding what energy sources Australia should embrace. While electricity generation by solar and wind is low carbon, they are both land and resource intensive when compared to nuclear power. This again is a direct result of the diffuse vs dense nature of the respective energy sources.
Solar power requires significant quantities of steel, glass and cement, while wind and hydropower rely on substantial amounts of concrete. More concrete is used than any other material during the construction of a nuclear power plant, however it still uses 20 times less than wind when measured on a per unit energy basis. Figure 6 illustrates this comparison where construction materials used in the major electricity generating technologies show nuclear power having the lowest materials requirement than any other source.
In addition to these major construction materials, solar and wind energy rely on a significant amount of precious and rare earth metals in the construction of panels and turbines. The projected scaling up of installed capacity of these technologies to meet emission targets is set to put significant demands on the mining of these metals. Silver, indium, as well as rare-earth metals praseodymium, dysprosium, terbium and neodymium have been identified as facing potential critical shortages unless global production output can increase many times over their current levels. By 2050 the annual need for indium for panel production alone (based on IPCC SR15 models of solar PV capacity growth) will exceed the present-day annual global production twelve times over. Such demand pressure can introduce long term economic uncertainty in solar and wind energy potentially making investment unviable.
Mining has also become one of the single biggest drivers of deforestation and biodiversity loss around the world. These environmental impacts associated with the scaling up of global mining operations to meet the demand of resource-hungry energy sources should also be an important consideration when deciding what is the best energy source to meet Australia’s long term requirements.
Due to their diffuse nature, both wind and solar energy require a significant area of land to capture and generate large amounts of electricity. The projected land-use intensity of different energy production techniques measured in km2 of impacted land per terawatt-hour per year for 2030 varies over three orders of magnitude (Figure 7). Nuclear power has the smallest land-use intensity. It is 30 times smaller than wind and 15 times smaller than solar PV.
While Australia has an abundance of land, transmission costs imply that electricity is best generated close to where it is used. Nuclear power’s small footprint means that it can be placed close to where there is electricity demand without displacing large amounts of land that would be otherwise used for other better suited productive activities, such as agriculture, commercial enterprise, or industry.
Given the importance of water resources in Australia, the use of water in nuclear power plants is often quoted as a barrier to development. In a typical light water reactor, water is used in two ways. The first is to convey the heat from the reactor core to drive the steam turbines. Since this process is a closed loop, water consumption is negligible. The second use of water is to remove the surplus heat from the steam circuit in a process of cooling in order for the generator to operate effectively. This cooling is typically undertaken in two ways: direct cooling via large source of water (river, ocean); or via recirculation where the heat is discharged through evaporation. If a water-cooled nuclear reactor was to be constructed in Australia, it would almost certainly be located on the coast where most of the demand of electricity is located. It therefore does not have to use an evaporative cooling process which requires large amounts of freshwater. Instead, seawater can cool the reactor’s secondary loop that is isolated from the core. Australia’s water security is not threatened by embracing nuclear power. Additionally, if nuclear power plants were to replace some of Australia’s coal-fired power stations (many of which rely on direct cooling from fresh water sources), they could actually free up these water resources for more beneficial uses.
National Energy Market modelling
Recent modelling of the National Energy Market (NEM) by the Electric Power Consulting Pty Ltd looked at six different generation scenarios on the NEM to determine a system levelised cost and carbon intensity for each alternative. The different generation scenarios, illustrated in the Figure 8, were:
- • Base case: An approximation of the current NEM generation mix;
- • Base case but with all coal replaced by gas;
- • Base case but with all brown coal replaced by nuclear;
- • Base case but with all coal replaced by nuclear;
- • The AEMO 2040 neutral case (outlined in their July 2018 Integrated System Plan);
- • A 100% renewables backed up with pumped hydro
EPC’s model is based on a Generation Mix model which focuses on whole of system costs rather than just the individual costs of each generation type. It incorporates both power system constraints (such that the generation mix is capable of supplying customer demand on a second by second basis) and economic dispatch constraints (picking the generation order dispatch according to lowest marginal cost). The generator costs were taken from the 2018 AEMO Integrated System Plan and the nuclear power costs are based on experience from a recent study tour to South Korea undertaken by the authors, adjusted upwards for Australian conditions. The final cost output, the system levelised cost of energy (SLCOE) is formally defined as “the average cost of producing energy from the combination of energy technologies chosen for the system over it’s entire lifetime, discounted back to today at 6% per annum”. Full details of the model can be found here.
The graphic above shows the carbon intensity of the six different generations scenarios plotted as a function of system levelised cost. The coal-rich base case remains the cheapest alternative at $69/MWh but a high carbon intensity of 0.83 tons/MWh. Replacing all coal plants with combined cycle gas plant more than halves the emissions (to 0.36 tons/MWh) but pushes the cost up to $97/MWh. The AEMO 2040 neutral case, which requires a significant scale up of renewables (+48 GW solar, +10 GW wind and +18 GW of pumped hydro) provides a reduction of carbon emissions similar the gas case (0.33 tons/MWh), but at a significant increase in cost: almost three and a half times greater than the base case ($247/MWh). For this case and the even moreso for the 100% renewable scenario, the costs of excess renewable capacity to help firm the supply of electricity and additional transmission costs drives up prices significantly. The 100% renewable case, which requires 110 GW of wind and solar and 30 GW of pump storage capacity for three days works out to give system levelised cost of $416/MWh, a staggering six times the base case.
The cases featuring nuclear power generation demonstrate the effectiveness of the technology to economically decarbonise an electricity grid. Replacing our brown coal generation with ~4 GW of nuclear power would reduce our carbon intensity by almost 23% off the base case, at only a fractionally increase of cost. Replacing all coal with nuclear power (about 19 GW worth), bring emissions dramatically down to 0.06 tons/MWh for a system levelised cost of $90/MWh.
For further decision on nuclear power costs, jump over the section in the Debunking Myths page of this website where we discuss more broadly the costs of nuclear power.
Perhaps the most exciting aspect of nuclear power is the new generation of designs currently being developed across the world. Small modular reactors (SMRs), high-temperature gas reactors (HTGR) and molten salt reactors (MSRs) are three examples of innovations that demonstrate marked improvements in safety, efficiency, and waste profiles. In addition, they open up a whole range of new applications currently not available in the world’s current nuclear fleet, including the burning of existing stockpiles of used nuclear fuel and various fuel and chemical cogeneration, including hydrogen.
With a federal prohibition still in place in Australia, it is very likely that once it is overturned and a regulatory framework put in place, many of these new designs will be commercially available. These designs have been actively pursued by state-run nuclear organisations, the well established nuclear power companies, and a large number of newly formed nuclear startups that have appeared throughout Europe and North America. Particular progress has been seen in Canada, where already a number of both SMR and Generation IV designs (Gen-IV) have been submitted for vendor review process to the Canadian Nuclear Safety Commission (a regulator considered friendly to nuclear innovation).
In fact, Australian nuclear scientists and engineers from ANSTO have been actively involved in the research of these designs. In 2016 Australia formally joined the Generation IV International Forum, an organisation of made up 14 member countries which is dedicated to the co-operation in research and development for the next generation of nuclear energy systems.
These new reactors provide some of the following advantages over existing designs:
A fundamental change in many SMRs and Gen-IV designs when compared to traditional light water reactors is presence of vastly improved passive safety or even full passive safety systems. Active safety systems of older designs are characterised on the reliance of functioning of engineered components during emergency situations. These new reactors feature passive safety systems that depend only on physical phenomena such as convection, gravity, negative reactivity coefficients or resistance to high temperatures, which is intrinsic to the reactor design and operation. For SMRs, which are designs whose generation capacity is less than 300 MWe, they have significant lower cooling requirements in case of emergency shutdown, such that many can be safely cooled by naturally circulating air without the need for operator intervention. Gen-IV designs are considered vastly safer than any previous generation of reactors, with many operating at low pressure, featuring automatic passive shutdown capabilities, and in the case of molten salt and some gas-cooled designs, are characterised by a melt-down proof reactor core.
High temperature output
All Gen-IV designs operate at temperatures significantly higher than current light water reactors. This high temperature operation vastly improves the efficiency of the conversion to electricity, and the heat can be directly used by nearby industry in all manner of process including mineral processing, recycling, desalination, hydrogen production and carbon-neutral fuel and fertiliser production. Not only does this provide a vital pathway to help decarbonise these carbon-intensive industries, it may also improve the economics of nuclear plant operation when cogeneration facilities are considered. This is expected to be especially important in the case of hydrogen which is likely to play an increasingly role in the global energy mix in the coming decades.
Of the six reactor technologies classed as Gen-IV, four utilise the fast neutron spectrum. Fast spectrum reactors have the promise of closing the nuclear fuel cycle, whereby used fuel can be reprocessed and then re-used again. This dramatically improves the fuel efficiency and will reduce the demand on uranium mining operations around the world. It also is an obvious solution to reducing the current stockpiles of used fuel from the world’s current reactor fleet. Along with this spent nuclear fuel inventory, fast reactors can also consume natural and enriched uranium, thorium, weapon-grade plutonium and depleted uranium. The molten salt reactors also have an additional flexibility of not requiring solid fuel fabrication, which is expected to reduce operating costs for these designs.
Improved waste profile
Another benefit of many newer designs is the ability to consume more of the fuel that is in the reactor. In light water reactors, fuel rods are removed from the reactor core every 18 months, and still contain about 97% of potential usable nuclear fuel. Gen-IV designs have significantly better fuel burn-up rates, making more efficient use of the fuel, which means less waste per unit energy produced. Fast spectrum reactors can potentially burn up all the actinides up in the fuel, so after re-processing only the fission products remain as waste. This waste is not only much smaller in volume, it take only 300 years to return to radioactivity levels comparable to natural uranium ore (compared to ~100,000 years for unprocessed spent nuclear fuel from light water reactors).