Solar challenging nuclear as potential climate change solution


From pv magazine USA

Nuclear power delivers almost 20% of all electricity in the United States, and about 50% of all low-emission electricity. Moreover, the United States has almost 100 nuclear power units operating more than 90% of the time, providing a steady base of power generation.

But moving forward, it seems nuclear has lost its swagger. Price increases, project delays, and cancellations have caused what may prove to be generational damage to nuclear power’s reputation. pv magazine USA has previously reported on industry pricing models, showing nuclear’s lagging pricing.

Now, Georgia Power’s Vogtle Unit 3 and Unit 4 – the nation’s only nuclear generating units currently under construction – have announced further delays and price increases. Conservative cost estimates suggest the two 1.117 GW facilities will require at least $30 billion to complete, including $3 billion in finance costs and $27 billion in construction costs.

Solar+storage costs

As solar and energy storage professionals, we must be conscious of the limitations of the sun, and the cost of energy storage. As we all know, the sun also sets. And while research suggests we can power 80% of the U.S. with wind, solar, and 12 hours of energy storage, being able to replace a nuclear power plant that runs 24/7/365 in wind, rain, snow, and sleet simply hasn’t been financially viable.

But is it today?

The chart above shows the price of solar panels from 1976 through the end of 2019. Here, we see prices fall by more than 99.8% from over $100 per watt down to nearly $0.20 per watt. Below, we see the price of battery packs starting in 2010 and ending in 2020, based on data from Bloomberg New Energy Finance. Here, we see costs fall from $1,191/kWh to $137/kWh – a price decrease of greater than 88%.

In both cases, we can expect prices to continue trending downward in both the middle and long term. And so, what can we expect to pay when we replace a nuclear power plant with solar power plus batteries?

Cash to spend

The new Vogtle reactors are rated at 1.117 GW each. Roughly, they’ll run at a 90% capacity factor. On an annual basis, the two units will generate 17.6 billion carbon-free kilowatt-hours of electricity. Already on site are two earlier nuclear units which have been running since 1987 and 1989.

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To generate that volume of electricity from solar power on an annual basis, Georgia would need about 7.3 GWdc of solar panels running at a 26% capacity factor. That would be equivalent to roughly 7% of the current U.S. installed solar capacity, which currently sits at just over 100 GW.

The resulting total capacity is now 10.55 GWdc of solar power. However, this 7.3 GWdc figure does not take into account battery charging losses or reduced sunlight in winter. So let’s offset battery charging losses by upsizing two-thirds of the solar (the amount to be stored) by 20%. Next, let’s account for reduced winter sunlight by increasing the total system capacity by another 20%.

In order to replace the two nuclear plants while the sun is down, the batteries would need to replicate two 1.117 GW power sources for 16 hours. The total energy storage capacity would be 39.3 GWh, after we add an extra 10% for safe measure.

Roughly speaking, the total cost of these solar+storage facilities would be:

  • $8.4 billion for 10.55 GWdc of solar power, fully installed at $0.80/watt
  • $527 million for hypothetical power grid upgrades at $0.05/watt
  • $7.8 billion for 39.3 GWh of energy storage fully installed at $200/kWh
  • Around $16.8 billion grand total, no incentives

So, Georgia, pv magazine USA just saved you more than $13 billion (as of today, anyway).

Some caveats

It’s almost certain that a solar facility of this magnitude – roughly 27,000 acres, or around 0.07% of Georgia’s land – would be split among many landowners in the state. If land lease rates in Georgia are comparable to what  might be earned in Pennsylvania, the project could provide as much as $27 million per year in income to Georgia landowners for decades to come.

Furthermore, the solar power plants would start generating electricity and revenue within about three years of the first signature, and two years after groundbreaking. The new Vogtle reactors began construction in 2013 (planning began much earlier), and are projected to complete in 2022-23.

With these considerations in mind, the repowering costs to get a solar+storage facility to a 40 to 80-year lifetime would likely be offset by the fact that the solar facility will enter service at least eight years earlier than the equivalent nuclear site. Additionally, during the solar plant’s operating lifetime, it saves massive amounts of regular operations and maintenance costs, as well as specialist engineer labor costs. The nuclear facility will easily last 40 years, and potentially as long as 80. However, the ongoing operations and maintenance costs are significant, as well as upgrades and equipment replacements that start to become necessary after 40 years. And sometimes, those $1 billion dollar upgrades go wrong, and a nuclear power plant gets trashed.

When we do repower the batteries and solar panels, they almost certainly will be cheaper, and operate at a higher efficiency, likely stretching the life of the solar facility to 50+ years. Again, this solar+storage facility would generate 20% more juice in the summer (when the power is needed most in Georgia) because we oversized it for the winter.

In the end, it would be best if we had a healthy ecosystem of clean energy generation systems that include nuclear. However, if we’re going to debate the costs of nukes vs. solar, then it is no longer a discussion.

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