Cost, stability and waste
Solar and wind power are steadily declining in price, and wind power already delivers cheaper electricity than coal and nuclear power – if stability is not a requirement. If the need for backup is added to the total costs, both fossil and nuclear power will be cheaper. All energy sources have waste challenges, where coal power is clearly worst for health and climate.
The cost picture is not as clear as many believe
It is challenging to find good cost estimates for the different sources of energy, and the answer tends to depend on who’s asking. As costs vary widely, it makes sense to look at average and median values by comparing prices from numerous power suppliers in several countries, rather than highlighting the cheapest or most expensive examples. Serious analysts do such comparative studies, while the media often presents exemplification using outliers.
Levelized Cost of Energy/Electricity (LCOE) is used to compare the costs of different energy sources throughout their lifetime. The weakness of this method is that it does not include the need for the establishment of power grids and ensuring stable delivery, for instance with battery as backup. If renewables are to dominate the world's energy supply, this cannot be ignored.
Few will disagree that wind turbines and solar panels drop drastically in price each year, although this does not necessarily give a good picture of the total cost. Solar panels may be free of charge without this leading to free electricity for the consumers. Much of this is related to mounting them in frameworks of aluminum, steel and concrete and place cables between them. Solar PV has the largest material consumption of all low-carbon sources, limiting how cheap the electricity can be. However, current electricity prices from solar and wind already match fossil fuel (and in particular coal) several places in the world.
While solar panels and wind turbines are steadily declining in price, nuclear power struggle with relatively high costs. The vast majority of this is related to the construction of power plants. The challenge has been a lack of standardization - it becomes expensive when each new power plant is made as a new prototype that must withstand almost everything. There is, however, a rapid development in this area. Rolls-Royce has announced that it will build 15 small modular and turnkey nuclear reactors in the UK, with then first to be completed in 2029. The price picture may be about to change.
While the price of solar panels and wind turbines drops, it remains to be seen that the price is lower than the alternatives when this is to be implemented on a large scale. This requires backup, and batteries are still very expensive. The cost of a battery park based on lithium-ion batteries with 4 hours capacity is several times higher than both solar panels and wind turbines per kWh. Although batteries are becoming increasingly cheaper, it is currently difficult to match fossil and nuclear power.
Nuclear has unprecedented stability
We rely on access to electricity when we need it, and a measure of stability is the capacity factor, which describes how much power is delivered relative to installed capacity. It is not a perfect parameter as coal, gas and hydropower plants can be quickly turned on and off, while nuclear power plants depend on constant delivery. Thus, the capacity factor for water and fossil power plants will be lower than achievable, typically controlled by the market. However, there is no doubt that, for stable electricity supply, nuclear power is superior. For solar and wind power, the situation is different as the delivery depends on weather, time of day as well as season.
Even hydropower struggle during periods of drought. Wind power provides electricity only when it blows, while solar has challenges with the need for electricity being greatest when delivery is the lowest (in the evening), which has led to the term "duck curve". Seasonal variations come on top of this. To overcome these challenges, backup in the form of batteries, nuclear, fossil or hydropower plants are needed. The systems need to be scaled so that power plants can deliver enough all year round. Nuclear power delivers stable 24/7 electricity, which is a clear advantage of this energy source, reducing the need for expensive batteries and installment of overcapacity of solar and wind.
All energy sources have a waste problem
All energy sources produce waste in varying amounts from construction and combustion. All power stations must be removed at some point, resulting in waste that must either be recycled or deposited. Because renewables have low power density, the amount of waste associated with the shutdown of powerplants is more than one order of magnitude higher than that of fossil and nuclear powerplants. Hydropower and solar powerplants produce the most waste, 14,000 and 16.000 tons per TWh, respectively, while gas and nuclear powerplants produce the least, 600 and 900 tons per TWh, respectively.
A clear advantage of renewables, except for biomass, is that very little waste is produced during operation. This is in stark contrast to fossil fuels that have large greenhouse gas emissions related to combustion, as well as emissions of hazardous particles, sulfur dioxide and nitrogen oxides. Coal power is by far the worst for climate, in addition to being most harmful to health, and causes premature death of 800,000 people each year. Combustion of coal also generates large amounts of ash. In 2018, the United States produced as much as 80,000 tons coal ash per TWh, which includes hazardous arsenic, cadmium, chromium and mercury. That is five times more waste than solar power plants produce. Biomass has far lower ash content than coal, only 3%, but, according to the IEA, still produces 20,000 tons of ash waste per TWh. Although as much as half of the ash from coal and biomass can be reused, there are large quantities that need to be deposited.
In stark contrast to coal, the waste associated with combustion in nuclear power plants is limited, only 2.5 tons/TWh. The problem is that it is radioactive, and requires extensive safety measures related to storage, which worry many. In Olkiluoto, Finland, radioactive waste from nuclear power plants will be stored deep underground for thousands of years, with associated uncertainties related to future leakage. However, this was thoroughly evaluated in a comprehensive study by the Finnish organization responsible for long-term storage of nuclear waste. They concluded that, if the waste starts to leak in a thousand years, then a person living directly above the landfill at the worst time (in about twelve thousand years) will be exposed to annual radiation equal to two bananas (which are radioactive due to their potassium content). Radioactive waste is also a resource for modern nuclear power plants, which can reuse waste and produce more energy. This is done in France and raises the question whether one should temporarily store such waste rather than permanently bury it.
Renewables are not without hazardous waste problems. Solar panels are made of glass containing lead and cadmium (a total of 5.7 tons per TWh), which not only can leak into groundwater during waste storage, but which can also leak while producing electricity. The problem was clearly highlighted when a tornado in 2015 destroyed 200,000 solar panels in California- where such panels are defined as hazardous waste.
In addition to potentially environmentally harmful chromium (14 tons per TWh) from wind turbines, turbine blades are largely made up of composite material that is currently not possible to recycle, and there are large quantities that will eventually have to be deposited. Wear of the turbine blades will also lead to the proliferation of microplastics, and although it is uncertain how large or dangerous these quantities will be, only one percent wear from the turbine blades of a wind farm will lead to many tons of microplastics scattered into the nature and drinking water.
Gas and nuclear power in combination with renewables provides stable delivery at acceptable costs
All energy sources have their advantages and disadvantages in terms of cost, stability and waste. While nuclear power has unprecedented stability, the energy source has clear challenges in terms of radioactive waste. The fossil fuels have large emissions of CO2 and harmful gases. Coal and biomass power struggle with large amounts of ash waste associated with the combustion process. Gas-fired power plants are both stable and cheap but must be combined with expensive carbon storage to limit emissions. Wind and solar power have very low greenhouse gas emissions, but produces significant waste, while providing unstable power and high costs if batteries are to be used for storage. It is therefore all about establishing a future power mix that maximizes the benefits and minimizes the disadvantages. This requires fact-based detail knowledge of how each energy source affects health, climate, the environment and the economy.