Over the past decade prices for solar panels and wind farms have reached all-time lows leading to hundreds of gigawatts worth of new renewable energy generation. As the saying goes though the wind isn’t always blowing and the Sun isn’t always shining. That’s why we should think about the future of energy storage
“If, for example, it’s a beautiful sunny day and we’ve got a superabundance of electricity we can’t use it.” – DONALD SADOWAY, Professor of Material Chemistry, MIT
The question of how to firm renewables, that is, ensuring there’s always Energy on demand no matter the time of day or weather, is one of the biggest challenges in the industry. We need a good way to store energy for later. And the main option right now is lithium-ion batteries.
You see them in products like Tesla’s home battery, the Power wall, and utility-scale system, the Powerpack. But though lithium-ion is dropping in price, experts say it will remain too expensive for most grid-scale applications.
“To get to battery for the electrical grid, we need to look at a further cost reduction of 10 to 20x. There are dozens of chemistry being looked at today there are hundreds of companies working on scaling up and manufacturing new battery technology.“ – WILLIAM CHUEH, Associate professor, Material Science And Engineering, Stanford University
Right now, lithium ion batteries just can’t store more than 4 hours worth of energy at a price point that would make sense. Plus, they pose a fire risk and their ability to hold the charge fades over time. To address this, there’s a cadre of entrepreneurs experimenting with a variety of different solutions.
“Now we’re seeing flow batteries, which are liquid batteries, and we’re seeing other forms of storage that are not chemical or battery based storage.” – DAN KAMMEN, Professor of Energy, University of California
And each has serious potential.
“We looked at materials on the periodic table that we’re actually going to be cost-competitive from day one.” – CRAIG EVANS, President, CEO, ESS Inc.
“Primus powers flow battery is a workhorse. thermal energy storage has a pretty unique opportunity to be extremely low-cost our solution will. We know today that solar P.V. and wind are the least ensive way to generate electricity.” – TOM STEPIEN, Co-founder and CEo, Primus Power
Which technologies prevail remains to be seen. But one thing is clear, for renewables to truly compete with fossil fuels, we need to figure out a better way to store energy.
From 2000 to 2018 installed wind power grew from 17,000 megawatts to over 563,000 megawatts. And solar power grew from a mere 1,250 megawatts to 485,000 megawatts. And it’s not stopping there. Renewables are expected to grow an additional 50% over the next 5 years.
In particular, the price of solar photovoltaics has plummeted far faster than all forecasts predicted, after China flooded the market with cheap panels in the late 2000s.
“All the Wall Street analysts did not believe that solar was gonna ever stand on its own without subsidies. Well, a few years later, even the most conservative analysts started realizing that actually solar was going to become economic in most parts of the world pretty quickly.” – JORG HEINEMANN, COO, Primus Power
And as Soler’s gotten cheaper, so to have lithium-ion batteries, the technology that powers electric vehicles, our cell phones and laptops. And thanks to improved manufacturing techniques and economies of scale, costs have fallen 85 percent since 2010. Now, wind or solar plus battery storage is often times more economical than peaker plants, that is, power plants that only fire when demand is high.
Tesla for example built the world’s largest lithium-ion battery in Australia, pairing it with a wind farm to deliver electricity during peak hours. But this doesn’t mean lithium-ion is necessarily economical for other Grid applications.
Basically, the market is right for competition. One of the main alternatives being explored is a flow battery. Unlike lithium-ion, flow battery store liquid electrolytes in external tanks, meaning the energy from the electrolyte and the actual source of Power generation are decoupled. With lithium ion tech, the electrolyte is stored within the battery itself.
Electrolyte chemistry is very but across the board, these aqueous systems don’t pose a fire risk and most don’t face the same issues with capacity fade. Once they scale up their manufacturing these companies say they’ll be price competitive with lithium-ion.
Hayward, California based Primus Power has been working in the space since 2009 and uses a zinc bromide chemistry. So far it’s raised over $100 million in funding, including a number of government grants from agencies like the Department of Energy and the California Energy Commission.
Primus’s modular EnergyPod provides 25 kilowatts of power, enough to power 5-7 homes for 5 hours during times of peak energy demand.
And for 12 to 15 hours during off-peak hours. Most systems use multiple EnergyPods though, to further boost capacity.
The company says what sets it apart is its simplified system. To date, Primus has shipped 25 of its battery systems to customers across the US and Asia including a San Diego military base, Microsoft, and a Chinese wind turbine manufacturer. It expects to ship an additional 500 systems over the next two years.
“Future customers are either independent power producers that are doing solar plus storage at utility-scale or larger commercial enterprises.” – JORG HEINEMANN, COO, Primus Power
Also operating in this space is ESS Inc, Oregon-based manufacture of iron flow batteries, founded in 2011. Its systems are larger than Primus Power.
They’re basically batteries in a shipping container and they can provide anywhere from 100 kilowatts of power for 4 hours to 33 kilowatts for 12 hours, using an electrolyte made entirely of iron, salt, and water.
“When we came into this market, we wanted to come into it with a technology that was going to be very environmentally friendly. It was gonna be a very low cost. It didn’t require a lot of volume on the production line to drive down cost.” – CRAIG EVENS, President, CEO, ESS Inc.
ESS is backed by some major players like Softbank Energy. The Bill Gates led investor fund, breakthrough energy venture,s, and insurance company Munich RE. Having an insurance policy is a big deal since it will make risk-averse utility companies much more likely to partner with it.
So far, ESS has six of its systems, called energy Warehouses, operating in the field and plans to install 20 more this year. It’s also in the process of developing its energy center, which is aimed at utility-scale applications in the 100 megawatts plus range. That would be 1,000 times more power than a single Energy Warehouse.
So far, key customers include Practo GD a private Brazilian energy supplier, and UC San Diego. But for all their potential, flow battery companies like Primus and ESS Inc still aren’t really designed to store energy for days or weeks on end.
Other non lithium-ion endeavors such as the MIT spin-off Ambri, faced the same problem with longer duration storage.
Form energy, a battery company with undisclosed chemistry, is targeting the weeks or months-long the storage market, but commercialization remains far off. So other companies are taking different approaches entirely.
Currently, about 96% of the world’s energy storage comes from one technology: Pumped Hydro
This system is pretty Straightforward. When there’s excess energy on the grid, it’s used to pump water uphill to a high elevation reservoir. Then when there’s energy demand, the water is released, driving a turbine as it flows into a reservoir below. But this requires a lot of land, disrupts the environment, and can only function in very specific geographies.
Energy Vault, a gravity-based storage company founded in 2017, was inspired by the concept but thinks it can offer more. Instead of moving water, Energy Vault uses cranes and wires to move 35-tonne bricks up and down, depending on energy needs, in a process that’s automated with machine vision software.
This system is sized for utility-scale operation. The company says a standard installation could include 20 towers, providing a total of 350-megawatt hours of storage capacity, enough to power around 40,000 homes for 24 hours.
The company recently received a $110 million in funding from Softbank Vision Fund, and it’s building out a test facility in Italy as well as a plant for India’s Tata Power Company. But some say the sheer size of the operation means it just can’t be a replacement for chemical batteries.
Then there’s thermal storage, it’s still an emerging technology in this space, but it has the potential to more energy for longer than flow batteries with a smaller footprint than gravity-based systems. Berkeley, California based Antora Energy, founded in 2017, is taking on this challenge.
Basically, when there’s excess electricity on the grid, that’s used to heat up Antora’s cheap carbon blocks, which are insulated inside a container. When needed, that heat is then converted back into electricity using a heat engine. Typically, this would be a steam or gas turbine. But Briggs says this tech is just too expensive and has prevented thermal storage solutions from working out in the past.
Recently, Antora received funding from a joint venture between the Department of Energy and Shell, who are excited by the company’s potential to provide days or weeks long storage. It’s still early days for Antora and Energy Vault though, and there are definitely other creative solutions in the mix.
For example, the Toronto-based hydro store is converting surplus electricity into compressed air, and UK and us-based Highview power is pursuing cryogenic storage. That is, using excess energy to cool down air to the point where it liquefies. These ideas may seem far out, but the investment is pouring in and projects are being piloted around the world.
While these companies are all vying to be the cheapest, safest, and longest-lasting, many also recognize that this is a market with many niches, and therefore the potential for multiple winners.
Overall, the energy storage market is predicted to attract $620 million in investments by 2040. But as always, it’s going to be tough to get even the most promising ideas to market. Of course, government policies and incentives could play a major role as well.
Implementing a storage mandate, as California has done, is another policy that many are advocating. With the right mix of incentives and ingenuity, we’re hopefully headed towards a future with a plethora of storage technologies.
The future is not going to be a mirror of the past, we’ve got to do something that’s radically different from everything that’s been done up until now, I’m really excited about that.