Everywhere you look today, it seems like we're on the brink of a clean energy revolution. Electric car sales are estimated to have topped a million units in 2017. Wind and solar installations are booming with rapidly declining costs. Goldman Sachs predicts that $3 trillion will be invested in clean energy over the next 20 years.
Yet still there is a fly in the ointment. We need cheaper and more powerful batteries to make clean energy work and the current technology, lithium-ion, is unlikely to get us there. So we not only need new and better batteries, we need new and better battery chemistries and those don't come around very often.
A new startup, Baseload Renewables, thinks it's found an answer from a surprising place, sulfur, which is a byproduct of petroleum refining and considered a pollutant. After decades of dependence on fossil fuels, we literally have mountains of the stuff, which makes it incredibly cheap. Ironically, we may have spent decades polluting ourselves into a green energy future.
The Hard Realities Of Cost
To understand the struggle to provide energy storage for the electrical grid, you need to understand the economics. Today, most American consumers pay about $0.10-$0.12 per kilowatt hour (kWh) for the electricity they use in their homes. The Energy Information Administration (EIA) predicts that wind and solar will cost about $0.05-$0.08 per kWh in 2022, so that looks pretty good.
However, current lithium-ion batteries for the grid cost about $350 per kWh and, as anybody who has owned a mobile phone or laptop computer for more than a few years knows, batteries degrade over time. If you assume 1000 charge cycles, that works out to about $0.35 per kWh per cycle.
So although batteries largely replace peaker plants -- which are far more costly and less efficient than conventional gas-powered electricity plants -- to be economically viable a battery would have to be roughly 10 times cheaper than current technology. ARPA-e estimates that works out to about $0.03 per kWh per cycle.
Reducing costs by a full order of magnitude is no easy feat, especially considering that lithium-ion batteries have been considered state of the art for a quarter century. Clearly, mere tweaking won't do. A completely new approach to battery research needed to be devised.
In 2012, the Obama Administration established the Joint Center for Energy Storage Research (JCESR) to solve the energy storage problem. Unlike a typical program, which would dole out grants to scientists who work in relative isolation at individual institutions, JCESR envisioned a collaboration between the National Labs, academic institutions and private industry.
Baseload Renewables emerged out of that effort. "JCESR created concentrations of expertise and outlined long-term goals, a technology roadmap for the future and helped achieve a long-term vision in the community," explains Ted Wiley, CEO of Baseload Renewables. That's been enormously helpful and our company, to a large extent, grew out of that vision."
In fact, Yet Ming Chiang, a renowned battery scientist and a co-founder of Baseload Renewables, was one of the first to receive a JCESR grant. It was through that work that he came up with the key insights that led to a breakthrough.
Putting The Pieces Together
One of the innovations embraced at JCESR has been its techno-economic model for developing new battery technologies. Typically, scientists begin their research by looking for materials that have the potential for better performance, but don't look closely at the costs for those materials. At JCESR, materials need to prove that they can be economically viable before research goes any further.
Working with the techno-economic model, Chiang and his team realized that any viable solution would start with component materials. Their first epiphany came upon seeing the Alberta sulfur pyramids (pictured above), which store waste from oil refining. Standing 100 feet tall and encompassing 25 acres, they represented a nearly endless supply of a viable battery material.
A second epiphany came when the team began to test a battery chemistry based on potassium permanganate. While the battery itself proved to be reversible, upon further analysis the proposed chemical reaction was not. When they looked more closely, they found that the reversible reactant was actually oxygen from the air.
So now they had a battery chemistry based on sulfur and air, two of the cheapest things imaginable, but a problem still remained. The cost of the power stack, the mechanism that converts the chemical reaction to electrical energy, was far too expensive. Yet after further experiments they realized that the dirt cheap materials they were using opened up new possibilities.
"When the economics of one part of the system change so significantly, it changes the economics of the entire system," Chiang told me. "What we found is that with the sulfur oxygen chemistry, the cost of the storage materials changed so drastically, that we could use a smaller power stack and achieve far better overall cost performance at longer durations."
The Road Ahead
The technology behind Baseload Renewables is impressive. "It's breaking ground on two fronts," says George Crabtree, Director at JCESR, "an exceptionally inexpensive battery based on sulfur, water and air, and a long discharge concept to backup solar and wind on overcast and calm days."
Still, there is a big difference between a technology that works in the lab and a marketable product. For a business to be viable, you need to not only deliver performance at cost, you also need to scale investment to demand.
That's where many startups go wrong. Excited about the possibilities, they become blinded to the perils that every company will inevitably face. In fact, one of Chiang's earlier companies, A123 Systems, went bankrupt even after receiving significant funding from President Obama's stimulus bill because of poor planning. Breakthrough Renewables is determined not to make the same mistake.
"Going from grams to metric tons is far from trivial and there are a lot of problems to be worked out," Wiley told me. We've seen many great technologies fail because they fell into the manufacturing trap, over-invested in capacity and found that demand didn't develop fast enough. Just because you build it, doesn't mean that they will come."
"So we're working to design a product that we can scale up through contract manufacturers and at the same time engaging with customers to create a continuous feedback loop," he continued. "We believe that will minimize the cost of inevitable snafus and maximize our speed to market at scale, quality and price."
If they are successful, we will be a step closer to a clean energy future. Next, we will need a viable new battery chemistry for transportation. JCESR scientists are currently working on two separate prototypes that may just get us there.