[chickenbig]

> Pure PV farms have minimal operational costs, nuclear has huge ongoing costs.

https://www.iea.org/reports/projected-costs-of-generating-el... page 59 table 3.13a puts O&M for nuclear in the USA at about 12 USD/MWh plus just over 9 USD/MWh for fuel, and table 3.14 puts O&M for utility scale solar at around 6 USD/MWh or so.

As for batteries, I think a few hundred USD/kWh is a reasonable guesstimate of cost (raw LiFePO4 cells are now sub-100 USD/kWh). Backing up each hour of production of a 1GW power station would cost a few hundred million USD, plus the cost of the solar farm to charge the battery up.

> 24 GWh per day of battery backed solar can dump half that power over 2 hours @ 6GW

At which point the transmission becomes the limitation; the grid operator probably wants a fairly stable flow of electricity through the wires to maximise utilisation so the 6GW is not realistic, nor would moving the electricity during the day to load-adjacent storage be efficient.

> Load following isn’t free for nuclear, any time you’re not operating at 100% you’re losing money.

I was responding to the point that solar panels are inherently more flexible because you can turn them off (because ...????). The same reasoning you've made about nuclear load following being uneconomical can be made about pure solar too.

> Nuclear inherently favors steady state operations due to the Xe pit

Operators change the boron concentration to offset the negative change in reactivity due to Xe-135 levels. For PWRs this is not a big problem, you just have to know it is there and do the calculation for I/Xe concentrations given the power levels.

[Retric]

I disagree with your quoted numbers. They aren’t current or inflation adjust to the same year, they also exclude several costs associated with nuclear such as insurance and setting money aside for decommissioning.

Ex: Your quoted fuel costs would be 0.9c/kWh in (2020 publish date) = 1.3c/kWh in 2024. O&M is often quoted as 4x fuel costs so 5.2kWh. “Fuel costs account for about 28% of a nuclear plant's operating expenses.” https://en.wikipedia.org/wiki/Economics_of_nuclear_power_pla...

A battery system which costs 200$/kWh and does 5,000 cycles = 5c/kWh. (Not every kWh from a solar farm needs to be stored, but this is just a ballpark comparison.)

> At which point the transmission becomes the limitation; the grid operator probably wants a fairly stable flow of electricity through the wires to maximise utilisation

You’re missing the forest for the trees here. Utilization follows demand, a state with peak demand of 6GW is going to have transmission lines setup for 6GW. But comparing the options you have nuclear with 4x 1.5GW reactors averaging ~40% utilization or batteries backed by solar. Run the numbers and Solar wins by a landslide.

[chickenbig]

> They aren’t current or inflation adjust to the same year

Page 41 states

    All costs are reported here in 2018 USD terms.

> several costs associated with nuclear such as insurance

Insurance is required for any industrial facility. The IEA report does not mention insurance. https://world-nuclear.org/information-library/safety-and-sec... puts insurance costs at around 1M USD/year (and separate conditional payments if an accident does happen), which divided by 9M MWh/reactor does not work out to much.

> setting money aside for decommissioning

For nuclear between 0.01 and 0.39 USD/MWh, and solar between 0.03 and 0.58 USD/MWh (depending on discounting).

> O&M is often quoted as 4x fuel costs

The data in the IEA report differs; it is somewhere between the fuel costs and twice the fuel costs.

> Not every kWh from a solar farm needs to be stored

Rooftop solar will cannibalise the utility solar's daytime market. The demand for utility solar's energy will for the most part occur when the sun does not shine.

> a state with peak demand of 6GW is going to have transmission lines setup for 6GW.

But this ignores the physicality of the grid; power stations are dispatched based on location as well as availability because transmission is expensive to build and limited in capacity.

> you have nuclear with 4x 1.5GW reactors averaging ~40% utilization

So your demand model is 2GW for 22 hours and 6GW for 2 hours, right? Are there many places which exhibit such wild swings? Dynamic pricing/load shifting, pumped hydro and OCGTs would be the traditional solutions.

[Retric]

> All costs are reported here in 2018 USD terms.

So even further out of date.

> O&M is often quoted as 4x fuel costs The data in the IEA report differs; it is somewhere between the fuel costs and twice the fuel costs.

Operations & Maintenance must include fuel costs… They are doing the thing where they break actual costs into several buckets to make actual operational costs seem lower. Refurbishment isn’t maintenance yadda yadda.

Same deal is going on with insurance. That 1.1 M / year covers some nuclear accidents, but the self insurance risk is quite significant even if you exclude the risk subsidy assumed by governments. IE: In the event of a large scale disaster insurance doesn’t make the reactor owner whole meaning their out the value of 1 or more nuclear reactors.

So yea 1.1M / year only works out to 0.01c/kWh but that’s an underestimate.

> Rooftop solar will cannibalise the utility solar's daytime market. The demand for utility solar's energy will for the most part occur when the sun does not shine.

Even assuming vastly more rooftop solar… PV panels produce power on a long tail curve not just at peak hours. Rooftop solar however only supplies the grid with power after the houses needs are met which is a significantly narrower area.

[chickenbig]

> So even further out of date.

Do you have references for how much a solar plant costs to build and maintain? A breakdown of costs would be good.

> Operations & Maintenance must include fuel costs…

I presume this was done to make section 5.4 "Fuel cost sensitivity" easy.

> Rooftop solar however only supplies the grid with power after the houses needs are met which is a significantly narrower area.

What about if people are over-specifying their solar PV system to make use of net-energy-metering (or high feed in tariffs) to reduce their annual bill (for instance in California)?

[Retric]

> What about if people are over-specifying their solar PV system to make use of net-energy-metering (or high feed in tariffs) to reduce their annual bill (for instance in California)?

Don’t just think about what happens when these systems are at 100% output. At 5% output that home is sucking power from the grid while the solar far is providing the grid with power. Which means even if every home and business adds panels a solar farm will still supply some electricity directly.

[kragen]

i agree that retric's reasoning about capital utilization efficiency applies to both nuclear and solar generation; in fact, it might be even more applicable to solar generation, because although the variable costs (cost of sales, you might say—proportional to power usage) for nuclear energy are low, they're virtually zero for pv. what i was saying about dispatchability is that nuclear plants typically can't be turned off; they keep generating power even when grid prices go negative, so the nuclear plant operator is literally paying someone with a giant resistor bank to burn up the energy the reactors are generating. (nowadays, hopefully they're paying someone with a battery bank to charge their batteries instead, but the future is not yet widely distributed.) your earlier comment about the ap1000 having significant dispatchability is welcome news, and https://en.wikipedia.org/wiki/AP1000 says there are six of them already in operation

there are particularly perverse grid incentives in some places which result in pv farms continuing to operate when grid prices go negative, too, but that's just a fake market; nothing about the generation technology requires that. if you close a contactor to short out your solar panel, it stops dumping any energy into the grid in nanoseconds, literally faster than the contact bounce in your contactor, without any damage or risk to the panel, power electronics, or the rest of the plant

with respect to transmission and battery storage, while there is some reason to locate pv farms some distance from the energy consumers—the consumers may be tightly packed and/or in a cloudy area—there is no reason to locate battery storage far away from energy consumers. you want batteries to be as spread-out as possible, as close to the load as possible, for many reasons: to avoid time-of-day congestion of transmission capacity (and even distribution! point-of-use batteries reduce or eliminate the need to overprovision distribution capacity); to prevent fires from spreading from one battery to another; to eliminate power outages caused by problems in transmission and distribution; to eliminate transmission and distribution energy losses for stored energy; and to reduce the opportunities for rent-seeking by transmission and distribution operators. the land use, climate, and safety considerations that sometimes limit the distribution of pv spreading-out don't apply to spreading battery storage out

as for the o&m costs: while the iea does wonderful work, and i appreciate you pointing to this very informative open-access report, this report is from december 02020, and it's largely built on data from previous years, much of it from plants built years earlier. the main topic of the tomas pueyo article we're commenting on here is how lower prices for solar panels are forcing people to design new solar power generation in ways that 'waste' solar panels in order to commensurately reduce the other associated costs, such as the operation & maintenance costs you refer to in table 3.14

with that in mind, looking at https://www.solarserver.de/photovoltaik-preis-pv-modul-preis..., pvxchange's current mainstream panel price index is €0,12 per peak watt, and in september 02017 (probably about the average time the plants profiled in the iea report were being built, and as far back as the data currently on that page goes, though archive.org has older versions) it was €0,42 per peak watt. that is to say, solar pv modules cost 250% more at the time. those solar farms were designed for a very different world than the one we live in today, one that could tolerate much higher o&m costs in order to make better use of the comparatively scarcer solar panels