Stationary Energy Storage Misunderstood

Dr Peter Harrop
energy storage
In our surreal world, we continue to subsidize fossil fuels. We rarely subsidize the huge missing link on the way to 100% renewables, which is providing massive amounts of delayed electricity. People misunderstand. They think we do. Uniquely, the IDTechEx report "Future Stationary Energy Storage: Hydrogen, Batteries, Gravity, Gas, Other 2022-2042" looks at all the proliferating needs and technologies on the essential 20-year timescale ahead. It finds that the problems are largely solved of very brief fluctuations previously avoided by the momentum of rotating machines used in fossil fuel plants.
Attention now turns to managing the mismatch of load to supply through 24 hours and then days as we reach the tipping point of 60% renewables where this becomes extremely impactful. With new pumped hydro taking too long to approve and install given mounting environmental and other concerns, people can be forgiven for thinking that the flood of giant lithium-ion battery installations now arriving solves all that. Recent orders have even included versions at gigawatt/ $2.4 billion levels.
However, the report finds that lithium-ion batteries struggle beyond providing four hours' delay and at the ever-larger sizes required and their biggest market - vehicles - will always get priority for deliveries. That matters because further shortages are predicted by IDTechEx analysis. Recycling the toxigens and rare metals spells mounting trouble anyway. IDTechEx concludes that lithium-ion batteries are only a stop-gap for stationary energy storage, with a window of opportunity of 10 to 15 years during which many misunderstood alternatives will eat away their market share more than is realized. The choice of these is far wider than is commonly reported.
Stationary energy storage is a term that refers to the heavy stuff not the battery in your smoke detector. It means rechargeable devices, battery, and non-battery, mostly providing delayed electricity, including, where necessary, massive pulses from a dribble of input. That includes the large battery for your solar house, the roadside solar fast charger for your electric car, the trackside unit grabbing braking energy from your electric train and shooting it back. Uninterruptible power supplies too with some becoming multi-purpose.
The largest storage market is for industrial and national grids such as short-term frequency control and energy shifting through the day to match supply to load. Little mentioned, two giant 500MW/5GWh compressed-air storage projects (electricity-to-electricity) are proceeding. One supplier's liquified air projects in Spain are 2GWh - around $1 billion. Chasing them, 2GWh of redox flow batteries over five years is a recent order. Why the variety? They match local specifics and largely overcome shortcomings of pumped hydro and lithium-ion batteries when faced with new needs such as storage in smart cities. IDTechEx predicts that they will increasingly win just on levelized cost of storage LCOS.
When we have a large amount of it, we shall need six months' storage for solar feeble in winter, even wind dead for months and none of the above are promising for this. Here, a tsunami of investment is pushing hydrogen storage proclaimed as the only solution. It is certainly improving in important ways but gravity storage by lifting weights has a great deal to recommend it and reinvented pumped hydro underwater or using heavy water are worth a look here. One finding is that hydrogen is important as part of a hydrogen economy. The analysts present a cooler look at its stand-alone economics.
Only the IDTechEx report "Future Stationary Energy Storage: Hydrogen, Batteries, Gravity, Gas, Other 2022-2042" gives an up-to-date appraisal of all of these and many others in the research pipeline. Its 2022-2042 roadmaps, product rollouts, and forecasts prepared by PhD level IDTechEx analysts worldwide, many of them multi-lingual.
The Executive Summary and Conclusions takes 46 pages because it summarises everything - definitions, evolving needs and technologies, roadmaps, forecasts, companies, and their product timelines. The Introduction then takes 36 pages to explain the types of electricity supply, location, and industry involved and their changing needs. Here are the options for the smaller systems needing small size and weight and larger ones focussing on levelized cost of storage and other factors named. Grasp the significance of intermittencies from seconds to seasonal and see examples from bus chargers to managing grid power through the day. Influences from arbitrage to feed-in-tariffs and opportunity in smart cities and under water are here.
Chapter 3 at 43 pages concerns hydrogen and ammonia storage notably for longest duration energy storage and the hydrogen economy. See zero-emission sourcing and vested interests. Both the positives and the negatives are closely examined and its likely positioning established - important but not all-conquering even for long duration because its efficiency is only one third to one half of the lesser known alternatives. Chapters 4 and 5 describe competitors for longest duration. Chapter 4 with 25 pages is gravitational energy storage lifting weights under sea or ground or to erects and disassemble towers. Come back grandfather clocks, all is forgiven! On rails or mountains? Chapter 5 is pumped hydro and particularly its new variants such as marine and using heavy water for hills if you have no mountains.
Next, the report looks at technologies that can deal with intermittencies of hours to weeks but probably not months. The above options will, to some extent compete with them in this space so it is getting very busy but it is the emerging massive market demand so there is room for many solutions. Chapter 6, 27 pages, deals with compressed gas, mainly compressed air with its considerable initial success but ending with the more speculative new carbon dioxide option. Chapter 7 at 13 pages deals with liquid air and its first serious orders while Chapter 8 also 13 pages covers thermal energy storage such as hot rocks or more-speculatively sand or aluminum, mainly focussing on the two leaders.
Chapter 9 takes a full 41 pages because they are newly successful but also becoming so varied from single to double tank, vanadium to zinc, iron, and other options all with very different pros and cons. Chapter 10 is yet another competitor in this space of minutes to weeks of storage - other batteries approaching readiness for stationary energy storage of minutes to hours or maybe more. Here is the very promising sodium-ion potentially predicted to beat lithium-ion on cost and environmental credentials, even availability. More speculatively there are aluminum, zinc, and high temperature options examined.
The technologies end with Chapter 11. Here are 26 pages on technologies useful for the shortest duration and largest pulses in and out and even 1MW uninterruptible power supply doubling as peak shaving. Here you see Li-ion capacitors, pseudocapacitors, new supercapacitors, and superconducting flywheels. The report then ends with many company profiles in Chapter 12.
IDTechEx finds that, on current trends and intentions, over one trillion dollars will be spent on stationary energy storage 2022-2042. That will create many one billion-dollar operations but it will not be enough to keep global warming below the apocalyptic 2C level. It is time for that to be understood. IDTechEx advises that much more needs to be spent on stationary energy storage but also on minimally-intermittent sources such as geothermal, airborne wind energy, wave, and tidal energy. A two-pronged attack is needed.
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