And Now This

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Comment by Willem Post on June 18, 2022 at 5:54pm

BATTERY SYSTEM CAPITAL COSTS, OPERATING COSTS, ENERGY LOSSES, AND AGING

https://www.windtaskforce.org/profiles/blogs/battery-system-capital...

 

This article has eight parts

 

Solar electricity increases with the rising sun, is maximal around midday, and decreases with the setting sun.

 

The Owners of traditional generating plants, to avoid grid disturbances, are required by ISO-NE, the NE grid operator, to reduce their outputs when solar is present, which decreases their annual production, kWh/y, and increases their costs, c/kWh, plus increases wear and tear of their plants, i.e., those services are not “for free”.

 

Electric grids with many solar systems have major midday solar output bulges, that are counteracted by the traditional power plants reducing their outputs. Combined-cycle, gas-turbine plants, CCGTs, perform almost all of counteracting (aka balancing) of the variable wind and solar outputs.

 

Those plants have to increase their outputs during the peak hours of late afternoon/early evening, when solar will have gone to sleep until about 8 or 9 AM the next morning.

 

Battery Systems Electricity Delivery Periods at Rated Capacity: At present, most recently installed battery systems have about 4 hours of electricity delivery at rated capacity, because the battery systems are primarily used to absorb midday solar output bulges.

 

Battery systems, in use during all of 2015, delivered electricity, on average, for 0.5 hours

Battery systems, in use during all of 2018, delivered electricity, on average, for 2.4 hours

Battery systems, in use during all of 2019, delivered electricity, on average, for 3.2 hours  

 

The increase in energy-delivery duration is required, because the main function of battery systems is to store excess wind and store midday solar output bulges. They discharge about 80% of the stored electricity during the peak hours of late afternoon/early evening; the other 20% are battery system losses. See Parts 2 and 4

https://www.eia.gov/todayinenergy/detail.php?id=43775

 

Battery systems usually perform multiple services at the same time. See image

 

A 2018 survey of 43 battery systems, performed by the Energy Information Administration, EIA, found 26 systems dealt with: 1) excess wind events, which occur at random, and 2) midday solar output bulges, which occur every day; 18 dealt with frequency regulation, 13 dealt with system peak shaving.

 

The annual battery throughput is greatest, by far, for dealing with excess wind and midday solar output bulges.

 

Battery System Usage is Extremely Low: Because of the efficiency loss between charging and discharging, batteries are a net consumer of electricity. Of the 150 battery plants (1,022 MW) that reported operating battery storage capacity on Form EIA-860 in 2019, 109 plants (850 MW) also reported electricity discharge and charge data on Form EIA-923 in 2019.

 

These 109 plants reported a total of 458,169 MWh of gross discharge from and 553,705 MWh of gross charge into the battery systems in 2019; an average round-trip efficiency of 85%, which excludes step-down and step-up transformer losses of 1% each.

 

1) About 230,000 MWh of the gross discharge in the PJM area was for serving its frequency regulation market (Figure 10 in URL). The PJM battery systems have a usage factor of almost 9%

 

2) About 110,000 MWh of the gross discharge in the CAISO area was for dealing with excess wind and solar storage. The CAISO battery systems have a usage factor of just over 9%

 

3) The ISO-NE battery systems have a usage factor of about 5%

See page 20 of URL

https://www.eia.gov/analysis/studies/electricity/batterystorage/pdf...

 

Multi-day Wind/Solar Lulls: If, at some future date, gas, oil, and nuclear power plants were no longer allowed, and were replaced by wind and solar systems, battery systems would need about a month of electricity delivery at rated capacity to cover:

 

1) Randomly occurring, 5 to 7-day wind/solar lulls with minimal output, that could be followed by another multi-day wind/solar lull a few days later

 

2) Seasonal variations of wind and solar outputs

 

Battery Owning and Operating Costs are Very High: This article will show the total cost of a 1 MW/4MWh battery system would be about $105,187/y, which includes: 1) the annual cost of financing, 2) the Owner’s annual return of investment, 3) the annual cost of operation and maintenance, 4) all other annual expenses. See Part 6

 

Most of cost should be allocated to the Owners of wind and solar systems, because: 1) they are the disturbers, and 2) most of the annual throughput of the battery system is due to dealing with wind output variations and absorbing midday solar output bulges.

 

Battery systems perform various other functions, but those services require much smaller throughputs than wind and solar systems.

 

This analysis assumes the net effect of financial benefits and subsidies is equivalent to reducing Owner’s annual costs by 45%.

 

US Utilities Capital and Operating Cost Data: US Utilities, which own a large number of various type battery systems, provide a minimum amount of information regarding the:

 

1) All-in, turnkey capital cost of their battery systems

2) Hourly and daily operating data, including overall, round-trip, system losses, and usages for each service. See Parts 1, 2 and 7

3) Revenues earned from each service

4) Annual cost of: 1) owner’s income, 2) cost of financing, 3) O&M expenses, 4) all other expenses 

5) How much of Owner annual costs is offset by subsidies and other financial benefits