Monday, April 22, 2024

Pumped Hydro vs Battery Grid Storage


I have owned lithium storage batteries for 10 years. 100 kw in my car and 40kw in storage for my solar system. I know a lot about their reliability, strengths, vulnerabilities and costs.

If you buy grid storage batteries today and for the next several years, you will buy Lithium Ion Technology. Other battery technologies are under development but are not commercially and affordably available for some time to come and we won’t know how they will actually perform over time.

Current battery storage has an ‘Achilles Heel’ compared to pumped hydro Storage.

The battery suppliers do not talk about these things.

Lithium Ion Grid Storage battery:

  • Tesla, the current leader in EV and grid storage batteries, uses the same batteries in their EVs and Powerwall grid storage offerings.
  • The technology is relatively new ( less than 10 years).
  • Battery storage is great in vehicles and for personal storage instead of home generators.
  • They contain rare, expensive metals.
  • Typically warranted for only 8 years but may last 15 years though experience has not proven this.
  • Current experience indicates they will degrade by 25% over their lifetime.
  • They are 90% efficient on day one but efficiency declines with age.
  • They are not practically usable below 10% of charge.
  • Charging from 80% to 100% takes a long time and frequently charging to 100% is harmful to the battery life.
  • Efficiency and charging capacity is degraded in temperatures below freezing or above 30C.
  • Total cost of ownership (mining, manufacturing, shipping, installation, operation, maintenance and environmental impact) is high.
  • They will be replaced and recycled after their useful life ( estimated 15 years).
  • Efficiency drops from 90% to about 75% over their useful life.
  • All of the infrastructure for battery grid storage is visible above ground.
  • Noise from cooling, transformers and inverters is an issue due to their size.
  • Fire and flooding will lead to explosion and toxic spills.
  • The money to buy them ends up in the US or China.
  • The costs is amortized over a lifetime 15 years.

Pumped Grid storage:

  • 70-85% efficient
  • Efficiency does not degrade with time.
  • Mature, proven, reliable technology for more than 100 years.
  • Can be fully charged and fully discharged as needed.
  • Efficiency and charging capacity is not impacted by temperature extremes or age of the technology.
  • Useful life (50-100 years) – many hydro plants are good examples of this.
  • None of the infrastructure (except for the pond. Not a dam) is visible or audible. All underground or water.
  • The pond, if built correctly, offers no flood risk but even if there was a concern then it’s not hard to open the valves and let the water out before floods can occur.
  • Being underground, they are not impacted by fire and are non toxic if damaged.
  • The money to buy this solution stays in Canada.
  • The costs can be amortized over a 50-100 year period.

The SGB PAC claim that Pumped storage is outdated technology. That is simply not stated accurately. It is proven technology, used globally and reliably for 100+ years. It is still the best grid storage technology.

Other issues:

Land Forces Base Meaford has occupied the area for 82 years. The land and marsh and shoreline species have survived live fire tank and artillery exercises and are surviving well.

Military personnel know how to clear munitions very well. They teach these skills to Ukrainian soldiers. This is not a major issue. Just a SGBPAC scare tactic.

If fish is a big issue then I urge the SGBPAC to attend a weekly information session to see how the design will mitigate this risk. Listening to this concern has already driven many engineering changes. Environmental studies are underway to ensure the risk is minimal. In any case, commercial fishing in Georgian Bay has been in decline for many years, for many reasons. Pumped storage pipes are unlikely to worsen the situation in a big way.

A final thought:

The question we need to think about is how many times we want to buy the grid storage solution. Investment today in battery technology will need to be repeated every 15 years. Pumped storage investment is good for 50-100 years. Whatever the cost of a battery solution might be, multiply by 5 to come to the 50-100 year comparable cost.

For technical details about grid storage refer to this link:

Dave MacDougall, Meaford


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