From pv magazine global.
Mining and refinement capacity simply cannot keep up. Experts from mining industry prognosticators to Elon Musk foresee a widening chasm between li-ion supply and demand over the next few years. As that gap expands, expect the stationary renewable storage market to adopt emerging technologies more aligned with the needs of the stational market – and expect organizations to diversify well beyond Li-ion to meet energy demands and advance their renewable transformation goals.
Li-ion batteries are particularly suited to electric vehicle (EV) use cases: Li-ion’s energy density is required to make EVs viable. As EV adoption increases over the next decade, so too will Li-ion costs as lithium supply pressures grow in severity. In short, EVs will eat up Li-ion supply out of necessity, while alternatives already better-suited to stationary use cases carve out their own niche.
Such stationary alternatives aren’t just going to be more affordable, they’ll also be matched to their purpose. As a battery technology, Li-ion has been the standard, but it has limits. Li-ion batteries bring comparatively high operating expenses. They supply power for relatively short durations. They struggle in locations with extreme temperatures – which an ever-increasing swath of the world falls into. They’re also limited in their lifespans, and show environmental and safety issues over the long term.
These challenges leave the future open to alternatives more appropriate to stationary applications. While lead-acid and redox flow batteries struggle with many of the same issues as lithium-ion, other technologies aim to improve on where Li-ion falters.
In my view, there are three energy storage technology categories quickly maturing and with a clear potential to lead the stationary energy storage market into the future.
Metal-hydrogen batteries differentiate from lithium-ion by bringing similarly-low-cost materials to longer battery life spans (ergo, promising superior long-term cost efficiency). Those lifespans can top 30 years, and do so without Li-ion’s safety or environmental risks.
Metal-hydrogen is a proven technology that particularly excels in extreme conditions: the battery chemistry is newly adapted from orbital spacecraft such as the International Space Station and Hubble Space Telescope, where metal-hydrogen batteries have now completed more than 200 million cell-hours.
Metal-hydrogen batteries are able to perform 30,000 charge/discharge cycles without degradation, and operate in ambient temperatures ranging from -40° to 60 °C. Because they have no moving parts, they eliminate the need for regular maintenance.
Cost-per-kilowatt-hour cycles for these batteries can reach as little as a couple of pennies. The performance and longevity promise of these batteries will first put them into large-scale stationary renewable energy storage use cases involving harsh climates and remote locations, such as solar plants, wind farms, or micro-grids in deserts or other severe, hard-to-reach environments, but their flexibility portends widespread adoption in a multitude of use cases.
Gravity-assisted batteries leverage towers up to 500 feet that are tethered to systems of cranes, cables, and pulleys that support large bricks of composite materials. Software orchestrating this large and quite-stationary mechanism can elevate the bricks to store energy, and then lower the bricks to send energy out to the grid.
By design, each brick represents an individual store of energy, and multiple bricks can easily be manipulated simultaneously using the puppeteer-like arrangement of pulleys and cranes. In this way, gravity-assisted batteries offer high-speed energy delivery or absorption, with millisecond response times.
The system relies on affordable commodity equipment and offers differentiating benefits to a variety of use cases. These include quickly restoring power to a grid after an outage, providing backup energy, or balancing grid energy—especially that supplied from renewables which deliver energy intermittently.
One drawback to gravity-assisted batteries for some scenarios is that they require a lot of space to operate. While they might not be suited for urban applications, deserts represent a sweet spot for the technology.
Brownfield, Superfund, and old mining or extraction sites have been proposed as ideal locations for gravity-assisted batteries. As the mechanical designs have yet to be proven on a large scale, some uncertainty remains—particularly around the design and cost of O&M. Still, it’s an interesting concept.
The future of sodium-ion batteries is more of a direct replacement to lithium-ion. The technology offers competitive improvements across several areas. Sodium-ion uses sustainable and available materials with considerably less of an environmental impact. At the same time, they are also low cost and project to at least match the energy density of lithium-ion through ongoing iteration.
Existing facilities that manufacture li-ion batteries could be converted to produce sodium-ion batteries, making it a seamless drop-in technology upgrade for stationary energy storage.
Because of energy density and performance similarity to lithium-ion, sodium batteries will likely be allocated to e-mobility applications rather than stationary storage, but they represent a potential, viable alternative to lithium-ion nonetheless.
Maturing range of technologies
Li-ion has been a foundational technology, accelerating renewable energy storage to the position it has reached today. That said, Li-ion largely achieved its status as the de facto technology because it was the only one available. Now, a maturing range of technologies has arrived to address needs across an expanding breadth of use cases, and some will serve those applications better than others.
Expect the next decades to witness a more competitive landscape, where the market selects the most powerful and valuable storage technologies for each specific purpose. Use cases will evolve to provide more value with the flexible and simple approaches now available to the market.
Randy Selesky is the CRO at EnerVenue. Previously, he was SVP at Greensmith Energy Management Systems; the battery storage provider was acquired by Helsinki-based Wärtsilä in 2017. Among his other industry experience are management roles at Rockwell Automation, Enernet Global, EnerNOC, and GE. He joined EnerVenue in 2021 following the company’s $125 million Series A.
The views and opinions expressed in this article are the author’s own, and do not necessarily reflect those held by pv magazine.
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Good write-up. IMHO there should be a legal requirement that ALL stationary battery installations (>2 MWatt-hrs) must be highly fire resistant and NOT use low-Z metals. We must do our best to have plenty of lithium available… for the HUGE demand that is coming soon (EVs, trains, boats, planes etc. ).
Back around 2007 people were pitching amorphous silicon, CIGS and several other thin films as alternatives to silicon. Good ole’ silicon is not just still standing – it’s thriving. If I had to bet on which battery chemistry is going to win in stationary applications I’d definitely bet on Li. Stationary storage is piggybacking on the battery learning curve that EVs are driving. This is hard to beat. I’m not a lithium expert but think it’s reasonable to expect Li prices to eventually come back down to earth and then fluctuate cyclically much like polysilicon prices plummeted a decade ago. Interestingly there was also a uranium gold rush back in the 50s. We should all remember Paul Ehrlich lost his commodity bet with Julian Simon.
Ultimately though, stationary storage is a bad bet. Public Utility Commissions may be approving these projects in 2022 but we’ve got a lot of evidence piling up showing these projects aren’t performing very well. If you look out at the horizon there are extremely dark clouds for stationary storage. You said it yourself, EVs are gobbling up all the lithium but in the future, I’d argue they’re also going to be gobbling up all the wind and solar.
First off I’m sure you’d agree EVs are going to add a ton of extra demand to the grid. The problem with the extra EV load isn’t the gross amount of demand – it’s the timing of demand. Particularly the uncontrolled charging during the evening peak. Utilities are going to have to shape all of this EV demand (or most of it) such that you keep it out of the high-load hours. This means we’ll be moving all the charging into the middle of the day and/or into the 10 PM to 4 AM time slot. These are exactly the time slots the stationary batteries were hoping to charge in.
Some folks say they won’t let utilities control how their EVs charge. Hey, if you want to pay $1/kWh during the evening peak instead of 5 cents/kWh in the low load hours go ahead. I think well over 90% of the charging is going to try to avoid peak charging and chase the cheap electrons.
A lot of this same logic applies to hot water heaters. People don’t tend to think of hot water heaters as peak loads but if you look at an hourly profile of hot water demand you’ll see a strong correlation with higher wholesale electricity prices. I actually applied for a job at a District Heating Plant once and this is where I found out this factoid. There are a couple hundred million water heaters in the United States and at 5 to 10 kWh of storage each, you’re looking at 1000 to 2000 GWh of storage. These are obviously just rough numbers but my general point is simply that these are big numbers. As I already mentioned water heating is a peak load so there’s added bang for the buck when you add load control to this type of device – i.e. these loads tend to flatten wholesale electricity prices and this makes arbitrage more difficult.
Another problem for batteries could be high-temperature thermal storage. Most industrial energy demand in the US is process heat and most of this is met by natural gas. The economics don’t work yet but if PV gets as cheap as we think it will you can make a strong case for storing electricity as heat. NREL proposed a technology recently with storage costs of $2 to $4/kWh. Process heat demand in the US is up around 3000 TWh/year. You’d likely want to carry multiple days of thermal storage so the total capacity could be in the 20,000 to 40,000 GWh range. Again, this is back of the envelop math but I’m just trying to roughly sketch out the Technical Potential – it’s very big.
The biggest monster that stationary storage faces is the over-build and spill strategy (AKA: implicit storage). The basic idea with overbuilding is that it’s cheaper to meet load by building extra wind and solar than it is to add storage. At the system level, we’ll have a situation where RE is going to cover 80 to 90% of all load – this is without storage.
If you look at weather statistics for the 1000 to 2000 hours per year that RE can’t meet load you’ll see that part of the reason why RE can’t meet load during these hours is that they often coincide with extreme weather events. These are multi-day events that can cover most of the continent. Ahem, the US is going through one of these events right now. Typically you’ll have about 20 of these days a year in grids like the US and Europe. Batteries aren’t a suitable solution to this type of problem. We’ll need gas for these hours. If you need gas to solve the extreme weather problem what’s the point of keeping around an expensive asset like stationary storage? California is finally coming to realize this and they’re looking to add four GW of desperately needed gas.
One final thing to mention would be V2G. Just for fun here’s some back of the envelope math. I once asked an EV expert what he thought the average EV battery capacity would be long term and he said 100 kWh per car. There are 276 million registered vehicles in the US so if all of them were 100 kWh EVs you’d be looking at 27,600 GWh
Imagine if just 10% of this capacity was available for V2G? This represents roughly 6 hours of US electricity demand. This wouldn’t come anywhere close to solving the extreme weather problem but it would be great for the type of diurnal balancing that people think stationary storage will be used for.
The future of Vehicles is in the ZPV (Zero Pollution Vehicle) that uses ONLY SOLAR ENERGY FOR CHARGING ETC.. and leaves NO Pollution during Operation or after life… and has an RR (Recycling Rating) of >90…
As far as Energy Storage is concerned … in a ZERO POLLUTION WORLD (say) by 2020.. the world will require 180,000 TWhrs/yr of Energy to meet ALL its Energy Needs (yes from PV Panels using AgriVoltaics on just 7% of the Global Farm land today) with 40,000TWhrs/yr of S2S (Sunset-To-Sunrise) Energy Storage/Generation.
This can be easily achieved by UHES (see you tube channel zeropollution2050 .. UHES, etc..) .. NO NEED FOR EXOTIC BATTERIES, SUSPENDED WEIGHTS, HYDROGEN ETC.. ETC.. JUST PLAIN OLD PHS … PUMPED HYDRO STORAGE .. using UHES to produce the 120TWhrs/Day …. or 40,000 TWhrs/yr … at the existkng 1TW Open Loop Hydro Sites….
The above UHES will meet the Global S2S Energy Storage/Generation needs…. none of these mickey mouse options proposed.. anccare doomed for failure… as they come up short…
Not mentioned is by far the largest battery storage, on demand generation in the world that is near free.
That is of course, EVs!! With a bidirectional charger it can supply the grid power on demand and each one carries 2-10 days worth of a home’s needs! YMMV
Let’s do some numbers. 3million EVs, about Tesla has produced at 100kwh each is 300GWh of possible storage and can use 50-80% of that with owner limits for time charged., etc.
That is just 1 small company’s output yet more than all the utility grid battery storage in the world. Future production will be 50x that as EVs take over. Since EV packs are on trend to last 20 yrs, 350k miles done right no noticeable battery loss, there really is no cost, well under $.01/round trip /kwh to store, generate on demand. What does a MegaPack cost/kwh? $.06?
So pretty much there will be no shortage of people wanting to buy cheap power so no more excess power and lots to sell on demand when needed even at 100% RE.
Now add these to home, building heat/cold storage heat pumps that once bought have near no cost using cheap power, lower deltaT times to charge with heap pumps efficiency moving 3-6 more heat/kwh, is near free as other than the compressor, not much to wear out.
The future will belong to homes, buildings, businesses and EVs because at retail prices, utilities can’t compete making RE, PV, small wind/CHP, CSP with waste biomass or synfuel backup at $.05/kwh retail will win in the end as the low cost producer at retail prices delivered on demand.
The future is so bright I got to where shades.
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