4 ms·

>Aside: assuming your point, it would be 12, not 24, as the batteries only shift from day to night and not vice versa) I think you are still missing the point.

>Aside: assuming your point, it would be 12, not 24, as the batteries only shift from day to night and not vice versa) I think you are still missing the point. you will use the battery exactly once per day and it provides 1 watt-hour each time. It isnt providing 1 watt-hour every hour of the day, nor is it providing 1 watt-hour every 12 hours. you discharge it once every 24 hours, or 365 times in a year. Compare this to nuclear, which is providing 1 watt-hour every single hour in a day. (1 watt-day = 24 watt-hours.

ben_w 2y ago
My use of "aside" was supposed to indicate that it was not critical to your core point that you re-emphasise here. Going through the numbers one step at a time and keeping track of the units, I believe the core problem is that the original was a meaningless unit in the first place, taking the total system construction cost and dividing by the power output (but expressing things in the middle in terms of energy produced over the whole year). (Not that it matters except to help me avoid such mistakes later, but because the numbers which are important are in units of $/Wh not $/W, I just assumed and that assumption led to me doing the thing I did). So, we have: PV for $3.06/W, nuclear for $4.34/W But that's not what energy is normally priced in, energy is normally priced in [money]/[energy] rather than [money]/[power], to convert between them I have to account for system lifetimes. The IAEA says nuclear plants have a lifetime of "between 20 and 40 years"[0], so I'll pick the half way value of 30. PV is generally guaranteed to last at least 20, but expected to last 30; as very few have been around that long and the tech is rapidly changing, I'll be pessimistic for that and pick 20. With those assumptions, this gives nuclear a cost per unit of energy of $16.5 / MWh (which is extremely cheap, so much so it's outright suspicious!); and PV a cost per unit of energy of $17.49 / MWh (which would also be extremely cheap, bordering suspicious, though by a smaller margin as the normal LCOE is lower anyway). For comparison, this graph suggests PV is usually about 3 times that and nuclear usually around 10-11 times that: https://en.wikipedia.org/wiki/Levelized_cost_of_electricity#/media/File:Electricity_costs_in_dollars_according_to_data_from_Lazard.png https://en.wikipedia.org/wiki/Levelized_cost_of_electricity#... Now, with these numbers, you don't really need to ask about the cost of storage, the nuclear option is just directly cheaper than the PV. I assume the surprise here is that maintenance costs are not included in construction costs? But then I'd be going down a completely different rabbit hole trying to dig into how Lazard reached those numbers. Would be good for everyone if China's actually done what people keep asking for with cheap nuclear power. [0] https://www.iaea.org/sites/default/files/29402043133.pdf https://www.iaea.org/sites/default/files/29402043133.pdf
- s1artibartfast 2y ago
  >My use of "aside" was supposed to indicate that it was not critical to your core point that you re-emphasise here. Your aside, while not critical, was also no true. The time between sequential discharging of a battery is 24 hours, not 12. The time between charging and discharging is irrelevant, just how many times you do it a year. I think you are also misinterpreting the parent post. I think they are intentionally providing [money]/[power]. This is a common format when talking about the cost of installed grid capacity. I should have converted your watt-hour numbers to [money]/[power] and used to for better comparison. >For comparison, this graph suggests PV is usually about 3 times that and nuclear usually around 10-11 times that: LCOE is a radically different form of calculation than what you used, and not comparable. It takes into account many other factors, most notably the time value of money.

ben_w 2y ago

My use of "aside" was supposed to indicate that it was not critical to your core point that you re-emphasise here. Going through the numbers one step at a time and keeping track of the units, I believe the core problem is that the original was a meaningless unit in the first place, taking the total system construction cost and dividing by the power output (but expressing things in the middle in terms of energy produced over the whole year). (Not that it matters except to help me avoid such mistakes later, but because the numbers which are important are in units of $/Wh not $/W, I just assumed and that assumption led to me doing the thing I did). So, we have: PV for $3.06/W, nuclear for $4.34/W But that's not what energy is normally priced in, energy is normally priced in [money]/[energy] rather than [money]/[power], to convert between them I have to account for system lifetimes. The IAEA says nuclear plants have a lifetime of "between 20 and 40 years"[0], so I'll pick the half way value of 30. PV is generally guaranteed to last at least 20, but expected to last 30; as very few have been around that long and the tech is rapidly changing, I'll be pessimistic for that and pick 20. With those assumptions, this gives nuclear a cost per unit of energy of $16.5 / MWh (which is extremely cheap, so much so it's outright suspicious!); and PV a cost per unit of energy of $17.49 / MWh (which would also be extremely cheap, bordering suspicious, though by a smaller margin as the normal LCOE is lower anyway). For comparison, this graph suggests PV is usually about 3 times that and nuclear usually around 10-11 times that: https://en.wikipedia.org/wiki/Levelized_cost_of_electricity#/media/File:Electricity_costs_in_dollars_according_to_data_from_Lazard.png https://en.wikipedia.org/wiki/Levelized_cost_of_electricity#... Now, with these numbers, you don't really need to ask about the cost of storage, the nuclear option is just directly cheaper than the PV. I assume the surprise here is that maintenance costs are not included in construction costs? But then I'd be going down a completely different rabbit hole trying to dig into how Lazard reached those numbers. Would be good for everyone if China's actually done what people keep asking for with cheap nuclear power. [0] https://www.iaea.org/sites/default/files/29402043133.pdf https://www.iaea.org/sites/default/files/29402043133.pdf

s1artibartfast 2y ago
>My use of "aside" was supposed to indicate that it was not critical to your core point that you re-emphasise here. Your aside, while not critical, was also no true. The time between sequential discharging of a battery is 24 hours, not 12. The time between charging and discharging is irrelevant, just how many times you do it a year. I think you are also misinterpreting the parent post. I think they are intentionally providing [money]/[power]. This is a common format when talking about the cost of installed grid capacity. I should have converted your watt-hour numbers to [money]/[power] and used to for better comparison. >For comparison, this graph suggests PV is usually about 3 times that and nuclear usually around 10-11 times that: LCOE is a radically different form of calculation than what you used, and not comparable. It takes into account many other factors, most notably the time value of money.