Long-Duration Energy Storage Could Solve the Dilemma of Harnessing the Sun

There’s a raft of issues being discussed by world leaders in Glasgow, Scotland this week at COP26. But few would argue against the importance of accelerating the transition from fossil fuels to clean energy to secure global net-zero carbon emissions by mid-century and keep the 1.5 degrees of warming set out in the Paris Agreement within reach, one of the top COP26 goals.

Where does the world stand on renewable energy today? On very shaky ground: while the percentage of renewable energy in the global energy mix has been growing, albeit slowly, it still represents less than a third (29 percent) of the share of global electricity generation, according to the International Energy Agency.

A number of countries are determined to shift the scales dramatically in favor of renewables. The Biden administration has indicated that solar power could cover 40 percent of the nation’s grid by 2035, as TriplePundit has reported (today it stands at 21 percent of all electricity generated in the U.S.).

Similarly, the European Union has set a target to raise the share of renewable energy to 40 percent for final consumption by 2030, up from roughly 20 percent in 2019.

So what have been the major roadblocks to raising that share of renewable energy? For many in both the public and private sector, it’s been the conundrum of long-duration energy storage to address the fickle nature of solar and wind.

No renewables strategy without long-duration energy storage

Everyone seems to be in agreement that long-duration energy storage is a key part of solving the dilemma. In fact, long-duration energy storage is a critical feature of the U.S. Department of Energy’s plans for integrating more wind and solar onto the gird without sacrificing reliability and stability. The Energy Department defines long-duration energy storage as a device or system that can store electricity for at least 10 hours or more.

The challenge is to make long-duration energy storage reliable and cost-effective. If so, it could be a key part of the renewable energy transition. As a recent paper published in Nature Energy showed, long-duration energy storage can reduce the costs of deeply decarbonized electricity systems by 10 percent if the storage technology’s costs are below $20 per kilowatt-hour. The savings could reach as high as 40 percent if long-duration energy storage costs could be reduced to $1 a kilowatt-hour.

Why has that been such a tough dilemma to resolve? It comes down to the essential nature of wind and solar power. Wind speeds vary by the hour, day and season; sunlight is absent all night, and cloudy weather can diminish solar performance by day—in other words, the intermittency of renewable energy sources has long been a problem waiting to be solved. And the sooner the better.

Technology is primed to meet the challenge

A new player on the scene, the Swedish firm Azelio, claims to have a viable solution. Azelio specializes in energy storage with electricity and heat production. The technology enables the energy to be easily dispatched, making renewable energy available around the clock. The energy is stored in recycled aluminum from which it is converted into electricity and heat with a total efficiency of up to 90 percent. The solution is scalable, from 0.1 MW up to 100 MW, according to the company, providing 13 hours or more of consistent, secure power, and with zero carbon emissions.

Azelio is among a number of companies jostling for space in the long-duration energy storage business. Along with Azelio’s thermal energy storage technology, these firms are developing long-duration batteries such as flow batteries, as covered by 3p, gravity-based energy storage, pumped hydropower, various forms of electro-chemistries and mechanical energy storage.

Each of these firms is looking to address the limitation of lithium-ion batteries, a commonly used form of energy storage that only last for a few hours. Linking sets of lithium-ion battery arrays, similar to those used in electric cars, to get more hours of energy has proven to be far too cost-prohibitive, many experts say.

“These technologies were not around some years ago, at least not ones that could handle volume installations for long-duration energy storage. That’s different today,” Azelio CEO Jonas Eklind told 3p. He added that the company has started to industrialize its long duration energy storage by implementing production that “we are able to scale up into the thousands.” Commercial projects or demonstration and verification projects of their solution, called the TES.POD, are up and running in Sweden, Dubai, Morocco and Abu Dhabi.

Balancing the grid to avoid blackouts

An important aspect of the technology is that it addresses imbalance in the grid that occurs due to the intermittency of renewable energy, Eklind adds. “When you put a very high percentage of intermittent production into the grid without enough energy balancing functions, you create chaos, and that chaos is pushed to the end user, in the form of extremely high energy prices or blackouts, like the kind we’ve seen in California.”

As he points out, in the transition from fossil fuel vehicles to electric vehicles that is picking up steam, as 3p has discussed, the need for the grid to handle ever higher percentages of renewable energy will increase.

“So, if you combine this intermittent production with a grid that's not really built for handling that, with the changed behavior of the end users, then you create a perfect storm,” Eklind said.

Azelio’s solution attempts to address that by optimizing the system for daily cycling,  Eklind explained. “That means you can charge it during daytime, when you have a lot of solar energy for six hours. Then you discharge that energy during the 18 hours when you're don’t have a sufficient amount of solar energy, running through that cycle every 24 hours.”

As a modular, industrialized system that’s compact, it’s designed to be used by any kind of business or institution, from a factory, a hospital, office park, agriculture business or similar, according to Eklind.

He notes that this is a new business model that may take some adjustment. “You’re basically replacing OPEX [operating expenditure] with CAPEX [capital expenditure], because when you buy a renewable energy system, you buy a system that can provide energy with zero fuel costs. The cost of the system is higher than the cost of the system for fossil fuel, which you pay for every day. In this case, the fuel isn’t the cost; it’s free—you just need the system to capture the energy and collect it. This different mindset towards how we think about energy is why this approach won’t just explode tomorrow morning, but I believe change is coming.”

In fact, new concepts such as energy-as-a-service, which provide customers with energy services such as lighting in exchange for a recurring fee, or, a subscription for solar energy, are starting to pique interest among businesses and investors. The global market for energy-as-a-service is projected to reach $88.4 billion by 2027, not least because companies see it as a way to take a big slice out of their energy costs as well as meet their own carbon reduction goals.

In a decisive year for climate action, fresh approaches and a renewed commitment to bridge the renewable energy gap can’t come fast enough.

Image credit via Unsplash