Will batteries solve the problem of the intermittent nature of wind and solar?
1. The quantity of lithium required to provide sufficient storage for grid support, nationally and , is prohibitive.
In 2021, the US used an average of 10700 GWh of electricity each day[i]. The 2021 report “The State of Offshore Wind in Massachusetts” cites a study done by the UMass Clean Energy Extension which suggested “roughly a day’s energy consumption” would be a useful amount of energy storage to back up an electricity supply dominated by renewables[ii]. If that were the case for all the US, 10700 GWh of energy storage would be “useful”. The amount of lithium needed for this quantity of battery backup would be 2.77 million tons[iii], or about 30 times the amount of lithium mined annually in recent years[iv]. This is just for grid backup, just for the US, so clearly a one-day storage capacity is out of the question.
As it is, lithium ion batteries are essential for the electrification of private and commercial vehicles, and as this critical factor in the effort to eliminate greenhouse gas emissions proceeds, the demand for lithium will increase accordingly. By comparison, energy storage is a “fix” for reliance on renewables, and of questionable value at that (see below).
2. Battery storage is a “low energy density” technology, which means that a large volume/space is needed to store a given amount of energy.
Consider: A new 300 MW (1200 MWh, based on 4 hour capacity) battery system at Moss Landing in California is described as occupying a building as long as 3 football fields[v]. This suggests that about an acre is needed for every 400 MWh of energy storage. In the illustration below as much as 12 GWh of storage would be in play, perhaps occupying 30 acres.
3. Other concerns with lithium ion batteries include
the 15-20% loss on each charge/discharge cycle,
the limited battery lifetime (15-20 years),
the environmental impact of lithium metal mining.For example, each ton of lithium extracted from the rich deposits in the South American “lithium triangle” requires about 500,000 gallons of water, in a region that is already a desert[vi].
It is worth looking more closely at Massachusetts’ anticipated need for energy storage. The figure is adapted from Figure 16 of the Massachusetts 2050 Decarbonization Roadmap[vii] and outlines a power generation scenario on a day when there are no winds (as observed on February 16, 2012).
The graph shows the resources expected to supply electricity to MA on such a day (which obviously do not adhere to the UMass ECC energy storage recommendation). Interestingly, storage discharge under these conditions, estimated to be as much as 12 GWh, amounts to a very small percentage of the required energy for that day (0.33% of approx. 360 GWh). The large shortfall of renewables in this example is made up primarily by imported power, which is of questionable availability if the low renewables supply extends over a broad region, as well as by natural gas-fired generation. Three take-aways from this scenario are: a) energy storage, which is costly to build and requires substantial real estate, is only suitable for dealing with very small shortfalls in renewables generation; b) solar is not capable of supplying all the load, even when demand is lower or when solar is at its most productive; and c) the only reliable back-up for renewables in the MA plan is natural gas, which would also be required for dealing with lack of availability of imported power. The MA 2050 Decarbonization Roadmap states that the sort of dead calm used in the above example occurs only 5% of the time, which raises the additional question of how natural-gas fired power facilities can otherwise be expected to sit idle.
[ii] https://www.salem.com/sites/g/files/vyhlif7986/f/news/state_of_offshore_wind_report_final-2021-10-13.pdf; prepared for the Joint Committee on Telecommunications, Utilities, and Energy; see p. 57.
[iii] “The Non-Solution Project”, a book by M. Beckers, 2016; and references therein; ISBN: 978-1537673806.