Turning sunshine and wind into 24/7 industrial heat and power — cheaper than fossil fuels

How Antora Energy is electrifying heavy industry

We started the Antora Energy journey by asking: How can we make the biggest positive impact on climate change?

We considered tackling many different problems, but we had two guiding criteria: It had to have the potential for massive greenhouse gas emissions reduction, and it had to be something with no clear solution and not enough people working on it. So, we turned to the largest source of greenhouse gas emissions in the world: heat and power for heavy industry. A staggering 30% of global emissions come from the manufacturing sector, and the only way we can restore a livable planet is by taking this down to zero. Today, there are simply no cost-effective, low-carbon solutions for these industries, but our future as a civilization depends on finding one.

Fossil is hard to beat

The problem is that fossil fuels are really darn good at what they do in heavy industry. There are two main reasons for this. First, they burn really hot, a feature that enables them to generate electricity and to supply heat to the hottest industries on the planet. Second, they’re crazy cheap. This killer combination has led to two centuries of fossil supremacy.

What’s holding back industrial electrification?

Electrification is rapidly decarbonizing transportation and has long been considered a path to replacing fossil fuels in heavy industry. But you may have heard that industrial heat is “hard to electrify.” That’s true, but not for the reason you might think. Most industrial processes are relatively easy to electrify from a technology standpoint. Sixty percent of industrial heat is used to heat water or air to temperatures less than 350°C, and these processes could be electrified almost overnight with reliable, off-the-shelf electric boilers and heaters. While high-temperature heat is somewhat more difficult to electrify, some high-temperature processes already have electric solutions. For example, most of the steel produced in the US comes from electric arc furnaces, which use electricity to melt steel at temperatures above 1500°C.*

The fundamental reason that electrifying industry is hard comes down to economics. Fossil fuels are just plain cheap, and electricity from the grid is often 5x the price of fossil fuels at an industrial site.

Solar and wind electricity is the opportunity of the century

Beating fossil fuels on cost will be incredibly difficult. But we are fortunate to be living in an unprecedented moment in the story of energy. For the first time in history, zero-carbon power from solar and wind is now cheaper than fossil fuels in many parts of the world, and this trend is accelerating on every continent. The cost of renewable electricity has fallen faster than nearly every prediction over the last two decades.

It’s hard to overstate the magnitude of this transition. In the next 30 years, every single major sector of our economy — including manufacturing, the electric grid, buildings, transportation, and agriculture — will be fundamentally transformed by cheap, renewable electricity. The transition has started and is accelerating at an astonishing pace. And industrial heat is up next.

Our investors look at this and see a $1T/year opportunity. We look at it and see a 10 gigaton/year opportunity.

But one critical barrier still remains

Wind and solar power are fundamentally intermittent. The sun doesn’t always shine and the wind doesn’t always blow. So we need a way to capture renewable energy when it’s available, store it for long periods of time, and then release it exactly when consumers need it, for as long as they need it. And of course, it has to be cost-effective! The total cost of your renewable energy, plus the cost to store it, must still beat the fossil-fueled incumbent.

Unleashing the full promise of wind and solar

At Antora Energy, we found a solution to this problem. We have developed a thermal energy storage system capable of turning sunshine and wind into reliable heat and power for heavy industry — cheaper than fossil fuels.

A deep dive into the technology

We ran the numbers

Before arriving at our current approach, we started from a completely technology-agnostic perspective and evaluated every possible way to store energy to find a solution to the intermittency of wind and solar. We ran the numbers on hydrogen, batteries, gravitational storage, compressed air, flywheels — you name it, we looked at it. This approach was driven by openness, humility, and a resounding desire to find the best solution to the problem at hand. We didn’t have a favorite going in, but instead deeply analyzed every option with a ruthless eye toward cost and scalability. We didn’t want to spend years of our lives developing a cool technology that doesn’t ultimately help solve climate change, so we worked hard to keep our analysis rigorous and honest. Even when we thought we had arrived at the right technology direction, we spent months just trying to kill the concept, trying to prove that it wouldn’t work, until finally a winner emerged.

Thermal storage won out, but it had key challenges

After this process, it was clear that thermal energy storage had an edge on other energy storage approaches because it has the potential for:

• Incredibly low costs,
• Stark simplicity, and
• Nearly infinite scalability.

Heating up a cheap, earth-abundant material was tantalizingly simple, and cheaper than any other way to store energy.

But there were two big problems with the way thermal storage had been attempted in the past. The first challenge was materials: What materials could meet the requirements around cost, performance, durability, and scalability? The second challenge was heat recovery: How do you turn the stored heat back into useful energy for a customer? These two challenges have stymied engineers and entrepreneurs for decades and ultimately hindered broad deployment of thermal energy storage in the past.

A simple and elegant solution

After exploring a vast array of possible storage materials and heat recovery schemes, what we found surprised us with its simplicity.

The first finding was that carbon is an extraordinary material. It is available at extremely low cost, it’s virtually unlimited on earth, it has a massive existing supply chain and a long history of widespread industrial use, and it has superlative physical properties. The more we understood about carbon, the more it blew our minds. Here’s why:

Raw material cost: Carbon blocks are among the least expensive bulk thermal storage materials available. These carbon blocks are derived from a solid carbon feedstock that is a waste byproduct of other industrial processes and one of the cheapest materials on earth.

Massive scale: Carbon blocks used in the metals industry are produced at ~30 million tons/year. Even a small fraction of this existing supply chain is sufficient to build terawatt-hours per year of energy storage capacity.

Conflict-free and non-toxic: Solid carbon is free of supply chain constraints, environmental justice issues, and toxicity concerns.

Exceptional thermal and mechanical properties: Carbon has best-in-class physical properties, including high thermal conductivity, high emissivity, excellent thermal shock resistance, high electrical conductivity, and high mechanical strength that actually increases at high temperatures. These properties lead to a whole host of operational benefits, such as being able to rapidly absorb massive amounts of electricity, and having an unlimited cycle life. Importantly, carbon’s high-temperature heat capacity is 30–70% higher than most conventional thermal storage materials, leading to significantly more energy stored per mass of material.

Extreme temperature stability: One particular physical property is so valuable it warrants a deeper discussion. Carbon is one of the most thermally stable materials in existence. It remains solid from room temperature up to over 3000°C. To put that into perspective, that’s about twice the temperature at which steel melts, and about half the temperature of the surface of the sun! This unique feature unlocks several key advantages:

1. Simplicity: Solid carbon blocks are just about the simplest way to store heat. They just get hot and sit there. Unlike with a molten material, there’s no need for valves, pumps, corrosion-resistant tanks, or other special containment systems. Every veteran of the concentrating solar power industry we’ve spoken with warned of the consistent challenges they encountered when using molten salts as a storage medium. A solid carbon medium side-steps these challenges. Simplicity is a big deal. Simple means cheap. Simple means reliable.

2. Energy density: A high maximum operating temperature enables a massive energy density (E = m*Cp*ΔT). A high energy density means smaller system footprints and levers down balance of plant costs (think containment, insulation, foundation, etc.). A compact system also enables smooth site integration. Industrial facilities are often densely packed with equipment, so sprawling stationary storage solutions just aren’t practical. These key advantages of an energy dense product are sometimes overlooked in the stationary energy storage world, but they are a critical factor for reaching low installed costs.

3. Ultra-high-temperature applications: Industries like cement, steel, and chemicals require higher temperatures than are feasible with conventional storage materials. Because of the unique thermal stability of our carbon, we can supply process heat at virtually any temperature required by our industrial customers. Heat flows from hot to cold, so lower-temperature thermal storage can only decarbonize low-temperature industrial applications. On the other hand, with the ability to operate over 2000°C, our carbon storage system can discharge heat at 1500°C or higher to support cement production or other high-temperature processes. This unique technology feature creates a pathway to decarbonize some of the heaviest greenhouse gas emitters on earth.

4. Cost of stored energy: We already talked about how the raw material cost is low, but what really counts is the cost per stored kWh of energy. The cost per stored energy for sensible heat energy storage is:

(cost to store energy) = (cost of raw material) / (Cp*ΔT)

In addition to having a very low raw material cost, carbon has one of the highest specific heat capacities of any thermal storage medium, both of which drive a lower cost per energy. But the ΔT — the temperature swing from fully charged to fully discharged — is just as critical to the cost equation. Because carbon is stable over such a large temperature range, our storage system can sustain a ΔT that is 2–5x higher than other thermal storage systems. This directly levers down the cost by 2–5x. The combination of low raw material cost, high heat capacity, and a massive temperature swing results in the carbon storage medium coming in as low as $1/kWh. That’s about 15x lower than molten salts and 50x lower than li-ion batteries, and allows our systems to have the multi-day discharge durations needed to meet the firm capacity requirements of industry.

5. Radiative heat transfer: The final advantage of the extreme temperature stability of carbon is related to heat transfer. Radiative heat transfer is proportional to the temperature of the source object raised to the fourth power (T⁴), so if you double the temperature you increase the radiative heat transfer by 16 times. That’s a powerful scaling factor! The upshot is that at temperatures above 1500°C, heat transfer works completely differently than we’re used to at room temperature. Radiation dominates over conduction and convection. For example, at 2000°C, over 99% of heat transfer occurs through light, not conduction and convection.

It may not be obvious at first that being in the radiative heat transfer regime is an advantage. But let’s step back and remember the two big reasons thermal storage has failed in the past: materials and heat recovery. We’ve discussed how carbon side-steps the pervasive materials challenges that limited widespread commercialization of thermal energy storage in the past. That leaves heat recovery, or how we extract thermal energy from the storage medium and convert it into a useful form for a customer. I won’t go into the details here, but suffice it to say that moving high-temperature heat with light is much simpler, cheaper, and more reliable than the alternatives.

So what exactly do we do with this intense thermal glow coming off our hot carbon? Two things. First, we use it to heat tubes containing a process fluid — such as steam or hot air — to the temperature used by an industrial customer. This can then be delivered directly to the customer to replace fossil-powered process heat.

Second, we shine it on modified photovoltaic panels (similar to solar panels) to generate electricity. Our team has developed a world-record-breaking solid-state heat engine that converts radiant heat into electricity with only a few micrometers of material and no moving parts. This is a story for another day, but for now let’s just say it’s quite useful to have a compact, power-dense, scalable, and efficient device capable of converting heat into electricity!

We operate these two discharge modes (heat and power) completely independently, giving plant operators full flexibility to meet their needs (unlike traditional combined heat and power systems).

Putting it all together, you can see a simple and elegant solution emerge. Here’s how our thermal energy storage system works:

• We use cheap, intermittent electricity to resistively heat big blocks of carbon.
• We wrap the carbon in standard industrial insulation to minimize heat leakage.
• We let light move thermal energy for us.
• We use this thermal energy to deliver process heat and power to industrial customers, with zero emissions.

Hot as hell and dirt cheap

I was chatting with a friend recently about why Antora’s approach is exciting, and she distilled it down nicely: “Hot as hell and dirt cheap.” Just like fossil fuels, we can create the extreme temperatures needed to generate electricity and supply high-temperature heat to manufacturing processes, and we can do it for cheap. But there’s one key difference: We do it with zero emissions.

Our team, our values, and our mission

We certainly believe that we have the right technology to decarbonize industrial heat and power. But that’s not where Antora’s true value lies. Our greatest assets are our team, our culture, and our unwavering dedication to our mission. So, I want to take a moment to share with you the core values that anchor our team and culture.

Our core values

Core value #1: Team and mission first. We are a mission-driven company: We exist to stop climate change for the future of humanity. Everyone on our team is truly, deeply motivated by this mission, and every decision we make as a company is fundamentally guided by this north star. To take on this monumental challenge, we believe we must grow and nurture our most valuable resource: our people. We believe that equity, diversity, and inclusion are deeply linked with our mission and make us better. We believe in investing in our people and supporting them as they grow.

Core value #2: Joy and laughter connect us. Stopping climate change is hard work, so we try to lift each other up and share joy everyday. This might sound almost frivolous at first, but there’s a lot underlying this core value. In order to be genuinely connected by joy and laughter, people need a foundation of equity, trust, empathy, inclusion, and wellbeing. In this way, we see experiencing joy and laughter together as one culmination of a healthy culture. And it just makes our lives more fun every day! We laugh a lot! :)

Core value #3: Built with humility and openness. This value might be one of the most unique and important aspects of our company culture. From the very beginning we strove to open our minds to every possible way to solve the problem of zero-emissions industrial heat and power. We have been willing — and excited — to pivot and adapt as we gain new information. We don’t think we have all the answers, and we absolutely love feedback and constructive criticism. We believe that every critique makes an idea stronger, and that the most useful criticism comes when invited with openness and humility. All throughout our journey, we’ve been open about our technology and company. We almost never respond to questions with “sorry, we can’t share that, it’s confidential.” Our experience has been that this openness fosters trust, encourages partnerships, and nurtures creativity. Along with openness, we strive to work with a deep humility. We of course believe that we’re working on the right solution, but we’re open to new and different ideas. We believe that this commitment to openness and humility engenders a healthy team culture and accelerates our progress towards the right solutions to climate change.

Let’s stop climate change together!

There is a rising movement of engineers, business leaders, policy makers, financiers, and others dedicated to stopping climate change for the future of humanity. In just the past year we’ve seen a marked shift in the momentum behind climate solutions. People are coming together with new hope and new passion for the teams and technologies that will decarbonize our energy system while expanding its benefits to everyone.

We feel extremely grateful to be a part of this wave of change. Over the past several years we have been fortunate to be supported by amazing backers at the US Department of Energy, the California Energy Commission, the National Science Foundation, and the Activate Fellowship. We now welcome with gratitude and excitement world-leading private investors from Breakthrough Energy Ventures, Lowercarbon Capital, Fifty Years, Shell Ventures, BHP Ventures, Grok Ventures, Trust Ventures, Overture VC, Incite, Impact Science Ventures, and others.

Most importantly, we have been fortunate to build a team of exceptionally bright, creative, kind, and dedicated people to help scale our solution toward global climate impact. Now, our team and company are at an inflection point. We’re growing rapidly, gearing up for commercial deployment, and looking for more people who want the mission of stopping climate change for the future of humanity to be at the center of their careers.

If this sounds like you, let’s talk.

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*While the actual on-site electrification of industrial heat is not a dealbreaker in most cases, broad industrial electrification has major implications for grid infrastructure. While some industrial sites have access to nearby wind and solar and can connect directly to these resources, other sites will need to get all of their electricity from the grid. In some cases, the grid interconnects at industrial sites will not be able to handle the new electric loads without upgrades, and at a broader level, if many industrial sites in a region electrify their heat it can strain grid infrastructure and require new transmission and distribution build-out. Finally, a number of regulatory and market barriers could keep industrial users from soaking up low-cost renewable power when it’s available on the grid. We’ll need cooperation and leadership from policymakers, regulators, energy consumers, and energy suppliers to ensure industry can electrify as fast as possible in areas where local wind and solar resources are insufficient and grid power must be used.