Cost of nuclear power

This is an early draft.

See also: Nuclear_power_reconsidered

There is much confusion over the measures of cost in power systems. To make a fair comparison of alternatives, we will use the two most fundamental - capital cost per kilowatt (kW) of generating capacity and operating cost per kilowatt-hour (kWh) of energy produced. Capital cost includes construction and all equipment, but not land or transmission lines, interest on loans, or government subsidies and taxes. Operating cost includes fuel, maintenance and administration, and a realistic estimate of depreciation, but not license fees and taxes. For storage systems, capital cost is normally per kWh of capacity, not total kWh delivered over a lifetime, and includes all ancillary equipment, like chargers and inverters.

Levelized cost is another measure that attempts to combine capital and operational costs in one number. It depends on the lifetime of assets, an assumed interest rate, and salvage value of the assets at end of life. Think of it as operating cost plus a mortgage payment.

(CC) Image: Jessica Lovering
Fig.1 Construction costs for Pressurized Water Reactors (PWRs) have varied due to the political and regulatory environments in each country.

Historical Costs

see Fig.1
Existing nuclear plants have been very expensive, due to the inherent risks in pressurized water reactors (PWR's) and the need for expensive structures and burdensome regulations to deal with that risk. Newer designs promise to be much simpler, safer, and manufactured on an assembly line as replaceable parts, rather than site built.

Cost of new designs

Vendors step up. We need your numbers.
ThorCon MSR:
$1200 per kW + $0.03 per kWh promised.
GE Hitachi BWRX-300:
$2250 per kW promised.

Fig.2 Market price of uranium, sold as yellowcake U3O8.

Cost of fuel

Uranium is traded on the New York Mercantile Exchange, currently at $110 per kg. See Fig.2 for the price history. Top producers are Kazakhstan, Canada and Australia.
Thorium is $30 per kg and is about three times more abundant than uranium.
A kilogram of uranium has 22.4 million kWh of stored heat energy. A Light Water Reactor (LWR) uses only 0.5% of this. A Fast Neutron Reactor (FNR) can use it all. If that FNR could generate 10 million kWh of electricity from one kg of uranium, the cost of future uranium could go to $100,000 per kg and not add more than a penny per kWh.
A CANDU reactor uses natural uranium (0.7% U-235). LWRs need 3 to 5% enrichment. Some newer generation reactors need up to 20% enrichment. Weapons grade uranium (and plutonium from old bomb cores) can be easily "down-blended" and provide decades of power for all these reactors.
Average cost of enrichment in 2021 was $99 per SWU (Separative Work Unit). To make a kilogram of 5% enriched uranium requires 8.85 SWU. A kilogram at 20% requires 45 SWU. About 90% of world enrichment capacity is in the five nuclear weapons states. These plus Germany, Netherlands and Japan provide toll enrichment services to the commercial market. Any enrichment activities outside of these IAEA approved countries can be understood as a threat to develop weapons.

Cost of alternatives

Capacity Factor (CF) is often ignored in discussions of intermittent sources like wind and solar. A typical rooftop solar panel system with a nameplate rating of 12 kW and a sunny climate in the Arizona desert will deliver 10 kW peak and 3 kW average over a year. A realistic cost per kW is therefore four times the often quoted cost. This does not include the cost of batteries, or any other storage that might be necessary for a regional utility. Storage is not necessary for rooftop systems, if the utility can provide full credit for power returned to the grid. The challenge for the utility is load following. If the fraction of total power on the grid from intermittent sources is too large, there will be extra expense for batteries or generators held as "spinning reserve" for rapid response when the intermittents drop out.

If the goal is 100% wind and solar, then we must add in the cost of storage. The most promising possibility is hydrogen at $0.12 per kWh (see below). Assuming this cost is distributed evenly over all demand, then the added cost per kWh depends on what fraction of the total power is delivered from storage. If that fraction is 1/3, then the added cost for all customers is $0.04 per kWh. This does not include capital cost of the storage system.

The biggest challenge in most storage systems is capital cost. A 10 GW regional grid with 3 GW average demand might need 100 hours of storage, or 300 GWh. This depends on the tolerance of the population for occasional outages when there is bad weather more than 100 hours, and there may be some additional cost for backup generators at hospitals, community shelters, and other critical services. Assuming that 100 hours of backup is the compromise, and we need to hold capital cost to no more that $10 billion, our storage facility can be no more than $30 per kWh (10% the current cost of batteries).

Rooftop Solar (no batteries):

$2,900 per kW (nameplate),
$11,600 per kW avg (25% Capacity Factor)

Wind Turbines

$770–$850 per kW (nameplate), down from $1800 in 2008.
$3240 per kW avg (25% Capacity Factor)

Batteries:

USA Average in 2019: $589 per kWh, down 72% since 2015.
Redox Flow Batteries: $25 per kWh promised.
Iron Flow Batteries: < $20 per kWh "incremental cost" promised.

Hydrogen:

Worldwide hydrogen production stood at 90 Mt in 2020, but since it was produced almost exclusively from fossil fuels, the result was close to 900 Mt of CO2 emissions.
"Green" hydrogen (no CO2) can be produced from water using electrolysis, but the cost is much higher.
There is also a possibility of separating hydrogen directly from water using a chemical process and abundant heat. See Energy_storage#Hydrogen for more on this.

$2 per kg promised by mid 2020s
$1 per kg ten-year goal set by DOE
$0.12 per kWh electrical energy production cost, assuming $2 per kg of H2, 50% overall efficiency, and zero for hydrogen storage capital cost.