Two articles with contrasting views of the future showed up in Utility Dive this week. The first was an opinion piece by an MIT professor referencing a study he coauthored comparing the costs of an electricity network where renewables supply more than 40% of generation compared to using advanced nuclear power. However, the report’s analysis relied on two key assumptions:
Current battery storage costs are about $300/kW-hr and will remain static into the future.
Current nuclear technology costs about $76 per MWh and advanced nuclear technology can achieve costs of $50 per MWh.
The second article immediately refuted the first assumption in the MIT study. A report from BloombergNEF found that average battery storage prices fell to $156/kW-hr in 2019, and projected further decreases to $100/kW-hr by 2024.
The reason that this price drop is so important is that, as the MIT study pointed out, renewables will be producing excess power at certain times and underproducing during other peak periods. MIT assumes that system operators will have to curtail renewable generation during low load periods and run gas plants to fill in at the peaks. (MIT pointed to California curtailing about 190 GWh in April. However, that added only 0.1% to the CAISO’s total generation cost.) But if storage is so cheap, along with inexpensive solar and wind, additional renewable capacity can be built to store power for the early evening peaks. This could enable us to free ourselves from having to plan for system peak periods and focus largely on energy production.
MIT’s second assumption is not validated by recent experience. As I posted earlier, the about to be completed Vogtle nuclear plant will cost ratepayers in Georgia and South Carolina about $100 per MWh–more than 30% more than the assumption used by MIT. PG&E withdrew its relicensing request for Diablo Canyon because the utility projected the cost to be $100 to $120 per MWh. Another recent study found nuclear costs worldwide exceeded $100/MWh and it takes an average of a decade finish a plant.
Another group at MIT issued a report earlier intended to revive interest in using nuclear power. I’m not sure of why MIT is so focused on this issue and continuing to rely on data and projections that are clearly outdated or wrong, but it does have one of the leading departments in nuclear science and engineering. It’s sad to see that such a prestigious institution is allowing its economic self interest to cloud its vision of the future.
What do you see in the future of relying on renewables? Is it economically feasible to build excess renewable capacity that can supply enough storage to run the system the rest of the day? How would the costs of this system compare to nuclear power at actual current costs? Will advanced nuclear power drop costs by 50%? Let us know your thoughts and add any useful references.
This paper from the American Economic Review found that consumers use a discount rate in excess of 15% in valuing residential solar power credits, compared to a social-wide discount rate of 3%. The implication is that a government can incent the same amount of solar investment through an upfront credit for as little as half the cost of a per kilowatt-hour ongoing subsidy.
The California Solar Initiative had two different incentive methods, the Performance Based Incentive (PBI) which was paid out over 5 years and the Expected Performance-Based Buydowns (EPBB) paid out upfront. The former was preferred by policy makers but the latter was more popular with homeowners. Now we know the degree of difference in the preference.
Panel imports were up 1,200 percent in fourth quarter 2017. That implies that installers were banking supplies to ride out the import tariff imposed by the Trump Administration. Unfortunately, it also means that the rapid technical and cost progress for panels may stall for that three year period.
A new study in Nature Energy finds storing rooftop solar can increase emissions and energy consumption.
My thoughts: Here’s the key statement for the finding in this report: “based on today’s Texas grid mix, which is primarily made up of fossil fuels.” If the either the marginal generation on the grid is low or no GHG (e.g., renewables overgeneration which is an increasing problem in California) or the connection to the grid is cut or restricted (e.g., in a microgrid), then this premise doesn’t hold.
This study relies on fossil fueled generation being the marginal energy source. It also focuses solely on operational changes with existing resources. The appropriate frame is looking at the change in generation investment with and without storage, so for example more renewables become cost effective with storage so the overall generation mix changes.
The second problem is that most of the production cost models are yet incapable of capturing reduction in flexible capacity use. That’s why the California Energy Commission has had DNV and LBNL working on modeling those resources. So the emission savings are underestimated.
The third problem is that savings in residual unit commitment (RUC) is underestimated in the models. These are gas units running on standby with no-load, to be available the next day for ramping, load following or reliability. Storage reduces the need for these resources as well. NREL recently released a study on the value of storage that captures this benefit.
If these findings are valid, then the existing Helms pumped storage plant is also increasing GHG emissions. One could go so far as to say that the value of pondage hydropower storage may be so diminished that relicensing conditions that require run of river operations may have little effect on costs and GHG emissions.