Nuclear vs. Solar - CAPEX & OPEX

A comparison of using nuclear vs. solar to deliver 1.4GW of baseload power

Fundamentally in the discussion of using nuclear vs. solar power we need to look at the costs of each. They’re both zero carbon. They both run fine when a storm or other event shuts down distribution. With our present technology stack, this is the choice for green energy.¹

Providing power during multiple days of overcast skies, a blizzard, etc. is an issue where we need additional solar generation and storage, the below assumes that does not happen. How long we might have degraded solar generation is a complex question. And if we’re pure solar, we can have gas backup for that situation, which is additional CAPEX and OPEX.

This analysis compares the total costs of delivering 1.4GW of reliable power year-round in Colorado using either a nuclear plant (APR-1400) or solar farms paired with three energy storage models. We assume no federal subsidies and use 2024 technology costs.

Key Assumptions

I found numbers all over the place, from reputable sources such as NREL, Lazard, etc. I think the following are what is being paid now.

1. Solar Generation : Colorado’s shortest winter day provides 4.5 peak sun hours.²

2. Solar Panel Generation : 400W³

3. Solar Panel Cost : $0.80/W (installed)⁴

4. APR-1400 Cost : $4.6 billion - $9.5 billion⁵

Nuclear Plant and Solar Farm

Solar Farm Design

To generate 33.6GWh/day in winter, the solar farm must produce 7.47GW DC capacity (33.6GWh ÷ 4.5h).

• Solar panels needed : 18.7 million (400W each)

• Land area (panels only) : 37.3 km² (14.4 mi²)

• Total land required : ~181 km² (70 mi²)⁶

• Solar CAPEX : $5.98B ($0.80/W * 7.47GW)

Storage Model 1: Batteries for Duck Curve + Gas

This model, which has significant CO2 emissions, is composed of batteries for the duck curve and uses gas turbines for the rest of the day. For this case we can remove ⅓ of the solar CAPEX/OPEX as we don’t need additional generation for overnight, just for the duck curve charging.

Design :

• Batteries : Cover 4-hour evening "duck curve" ramp (5.6GWh).

• Gas Plant : Provides 1.4GW for remaining 15.5 hours.⁷

Costs :

• Batteries

  • CAPEX : $840M ($150/kWh)

  • OPEX : $112M ($20/kWh/year)

• Gas Plant

  • CAPEX : $1.4B ($1,000/kW)

  • OPEX : $42M ($30/kW/year)

• Transmission

  • CAPEX: $100M

• Total

  • CAPEX : $8.32B

  • OPEX : $303M/year

Storage Model 2: 24-Hour Batteries

This model uses sufficient batteries to provide a continuous 1.4GW outside of the times the solar can directly provide it. This is the all renewables approach. This model adds 10% CAPEX/OPEX to the solar because the batteries are only 90% efficient..

Design :

• Batteries : Store 33.6GWh (accounting for 90% efficiency).

Costs :

• Solar Farm

  • CAPEX : $6.64B (8.3GW DC)

  • OPEX : $166M ($20/kW/year)

• Batteries

  • CAPEX : $5.6B ($150/kWh)

  • OPEX : $739M ($20/kWh/year)

• Transmission

  • CAPEX : $100M

• Total

  • CAPEX : $12.34B

  • OPEX : $905M/year

Storage Model 3: Batteries + Pumped Hydro

This model uses pumped hydro as the backup. So mid-day the solar is both providing power and pumping up the water from the lower lake to the upper lake. It then uses that hydro over the rest of the day to provide a continuous 1.4GW. This model requires an additional 20% solar CAPEX/OPEX because pumped hydro is only 80% efficient.

Design :

• Batteries : 4-hour duck curve (5.6GWh).

• Pumped Hydro : Stores 21.7GWh (80% efficiency).

Costs :

• Solar Farm

  • CAPEX : $7.04B (8.8GW DC)

  • OPEX : $176M ($20/kW/year)

• Batteries

  • CAPEX : $840M ($150/kWh)

  • OPEX : $112M ($20/kWh/year)

• Pumped Hydro

  • CAPEX : $3B ($2,000/kW)

  • OPEX : $70M ($50/kW/year)

• Transmission

  • CAPEX : $100M

• Total

  • CAPEX : $10.98B

  • OPEX : $358M/year

Nuclear Option: APR-1400

We compare each of the above models to the nuclear model.

Nuclear Plant

• CAPEX : $4.6B - $9.5B

• OPEX (including refueling) : $287M

Cost Comparison

Does not include interest/cost of money

Conclusion

• Nuclear takes longer to build but is otherwise cheaper.

• Solar + Gas is competitive over 20 years but relies on fossil fuels.

• Solar + Batteries is prohibitively expensive due to storage costs.

• Solar + Pumped Hydro balances CAPEX and OPEX but requires suitable geography and the hydro takes longer to build.

The bottom line is nuclear, even without taking into account the additional batteries or gas needed to handle overcast days, blizzards, etc. when solar generation drops precipitously, is cheaper.

It is fair to say that solar panel and battery efficiency will keep rising and costs will keep falling. But by the same measure, if we build 100 APR-1400 nuclear plants, the cost of that 100th plant will be a lot lower than the present $6 billion because we’ll learn a lot with each build that can be applied to the next.

So why are we building more solar farms instead of nuclear?

1. I already did the same for nuclear vs wind - see here.

2. NREL Solar Resource Maps.

3. NREL Photovoltaic Research

4. NREL Annual Technology Baseline

5. Cost Analysis of a Nuclear Power Plant

6. Total land includes spacing, access roads, and maintenance.

7. A bit less than that time because the solar is generating over about 9 hours of the day in winter. It’s just at under 100% for a fair amount of that.