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The high-hanging fruit is reachable. The question is how soon?

To decarbonize sectors such as steel and long-distance transport, we need to take partial steps in the short term, such as increased efficiency, reduced demand and greater circularity, while also investing in new technology and infrastructure for the long term.

ladder in a fruit tree

Photo via Shutterstock/Glebchik

When it comes to decarbonization, nothing is easy, but some measures are easier than others. Rapid, widespread deployment of renewable energy is one of the best near-term solutions, and it will reduce emissions substantially but not entirely.

To reach net zero, it will also be necessary to clean up sectors that don’t have readily deployable solutions, like heavy industry and long-distance transport. In technical parlance, these sectors of the economy are called "hard to abate." We can think of them as the high-hanging fruit of climate action. They may be challenging to reach, but they constitute about 30 percent of global CO2 emissions, so they can’t be ignored.

Technology-enabled strategies to reach the high-hanging fruit were a frequent topic of discussion at VERGE 21, GreenBiz Group’s annual climate tech conference. The virtual event featured entrepreneurs, corporations and policymakers who are approaching the challenge with a mix of long-term ambition and near-term pragmatism.

"We’re in a situation where no one knows exactly how to get to where we need to go as a civilization, so we need unreasonable goals," said Paul Hawken, author of the books "Drawdown" and "Regeneration," during his VERGE 21 closing keynote, "and the beauty about technology is that there are dreamers who say, ‘Why not? Why don’t we try it?’"

Let’s dive into two major categories of high-hanging fruit: materials and long-distance transport. For each area, there are three questions that we need to explore to really understand the space. First, why is it high-hanging fruit? Second, what are some potential solutions? And third, who are the dreamers turning ideas into action?

Steel making workshop

Image of steel-making workshop via Shutterstock/Zhang Sheng

The hard business of hard materials: Steel and concrete

What makes these sectors high-hanging fruit?

Steel and concrete are the building blocks of the modern world. They’re present in almost all buildings, bridges and other physical infrastructure. They’re also major contributors to climate change, largely due to their energy-intensive manufacturing processes. Steel and concrete are each responsible for about 8 percent of global emissions.

"There’s growing evidence that the way we make our buildings, the materials we make them out of, are having a similar scale [of emissions] to the energy used to operate buildings," said Wes Sullens, director of the U.S. Green Buildings Council’s Leadership in Energy and Environmental Design (LEED) program, at a VERGE 21 breakout session.

On the operations side, emissions from the built environment have the potential to decline due to improved efficiency. Energy efficiency is a classic example of low-hanging fruit. Improvements are often low-cost to implement, and they begin saving money right away. It is much more difficult to reduce carbon emitted from the production of building materials, known as embodied carbon.

Steel and concrete both require extremely high temperatures in their production process, usually achieved by burning fossil fuels, and they involve chemical reactions with carbon dioxide as a byproduct. Both those things are extremely tricky to make happen without putting carbon into the atmosphere.

We’re in a situation where no one knows exactly how to get to where we need to go as a civilization, so we need unreasonable goals.

As buildings become more efficient, the high-hanging fruit that’s literally built into them becomes responsible for a relatively larger share of their overall emissions. While it’s not possible to address the embodied carbon in existing buildings, it’s a critical issue for new buildings, which are being constructed at a rapid clip as the world becomes more urbanized.

"Once the building is built, it’s too late; you can’t make those interventions anymore," said Rob Niven, founder and chief executive officer of CarbonCure, at VERGE 21.

What are the solutions?

Niven’s company CarbonCure has developed a novel technology to pump CO2 into concrete, where it mineralizes and remains permanently stored. The result is a stronger concrete that can be sold on the market at a similar price to traditional alternatives.

Paired with carbon capture and renewable fuels, CarbonCure’s concrete could theoretically be carbon neutral or even negative, but those technologies are still a long way from being commercially feasible.

Similarly, for steel, new technology offers a pathway to mitigation that’s promising but lengthy. Steel production traditionally requires melting iron ore and exposing it to a source of carbon, usually coal, which removes the oxygen and leaves pure iron.

"That same process that’s been going on since the Iron Age, that’s what’s going on in the heart of a blast furnace today," said Adam Rauwerdink, vice president of business development of Boston Metals, at VERGE 21. "What we do is we take carbon entirely out of the equation and instead of carbon use electricity."


CarbonCure Technologies is among the startups experimenting with injecting carbon dioxide into cement during the production process to help capture and sequester emissions.


Boston Metal is developing a process called molten oxide electrolysis, which uses electricity to separate oxygen from the iron ore without a carbon-emitting blast furnace. If that electricity comes from a renewable source, then this key step of steelmaking will be emissions-free. The company has plans to begin commercial operation by the middle of this decade, but it still has several steps remaining to prove out the technology.

In the interim, there are still ways to cut emissions from steel and concrete before stopping them completely. A big one is tapping into the circular economy by recycling old materials as much as possible. A 2018 report from a coalition called the Energy Transitions Commission estimated that a more circular economy could reduce CO2 emissions from materials like steel and concrete by 40 percent globally.

"First and foremost, if you can reuse things and not make new, that would be a great strategy," said Sullens.

Concrete is not directly reusable, but CarbonCure and other companies are turning used concrete and concrete byproducts into other useful construction materials. On the other hand, steel is relatively easy to recycle without loss of quality. According to Rauwerdink, recycled steel only produces about one-quarter of the emissions of virgin steel.

"Some of the first, earliest, greenest steel is going to be the recycled," he said.

Who’s taking action?

It’s often up to the building owner to make decisions about the best route to addressing embodied carbon. Companies are using data tools such as the Embodied Carbon in Construction Calculator (EC3) to measure these emissions and identify options for lowering them.

Fortunately, many interim solutions don’t break the bank. A study from RMI tallied up strategies for reducing embodied carbon in three common building types and found it was possible to reduce embodied carbon by 19 to 46 percent for less than 1 percent of additional cost.

"There are lower carbon options on the table right now for your buildings that do not cost any more money," said Katie Ross, Microsoft’s global real estate and facilities sustainability lead, during VERGE 21. "It’s about having the data in hand and knowing what opportunities you have and selecting the lower carbon option."

Even for solutions that cost a little extra, there are companies willing to jumpstart the market with early purchases. A formal group of these companies called the First Movers Coalition was announced at COP26, with members agreeing to meet general targets for procurement of zero-carbon technologies (including zero-carbon steel) by 2030. 

Also, it’s not all on the private sector to drive change. Governments buy about 40 percent of the world’s cement and 25 percent of the world’s steel.

"Government buys far more concrete than any one company," said Niven.

In the U.S., the newly passed infrastructure bill will keep Uncle Sam a regular customer of these industries, as the federal government invests in bridges, buildings and other construction projects. These purchases create an opportunity for instituting green procurement policies that prioritize low-carbon options, helping to further stimulate the private market for these solutions.

Regardless whether it’s the public or private sector taking ambitious steps towards the high-hanging fruit, the imperative is moral as well as financial.

"It’s not only our opportunity but our responsibility to do more," Ross said. "Those companies that can do more, should."

Getting from point A to point Z: Long-distance shipping, aviation and road transport

What makes these sectors high-hanging fruit?

In our globalized economy, it’s often necessary to move heavy items across long distances, and unfortunately that’s something fossil fuels are uniquely good at powering, due to their high energy density. As a result, heavy-duty transport emits a lot of greenhouse gas emissions. Maritime shipping is responsible for 2 to 3 percent of global CO2 emissions, and it’s about the same for aviation. Trucks and buses are responsible for 5 to 6 percent.

Passenger cars are good candidates for electrification, because as far as motor vehicles are concerned, they’re small and tend to travel short distances. Heavy-duty transport is much harder to electrify. The massive batteries required would drastically reduce the efficiency of large vehicles, would be impractical to charge on many road routes and would be all but impossible to charge in the middle of the sky or the ocean.

What are the solutions?

For ships, companies such as Mitsubishi are considering ammonia as a promising alternative to fossil fuels, according to Pradeep Venkataraman, a senior manager at Mitsubishi Heavy Industries America. Ammonia is clean-burning, high-density and easier to store than other alternatives. 

However, no cargo ships run on ammonia, and most ammonia today is produced from natural gas, not the green hydrogen (produced from renewable electricity) that would be necessary to make the fuel truly carbon free. Mitsubishi and others are working on designing ammonia-powered ships, and many companies are working to create more green hydrogen, but these technologies are still far out on the horizon.


Neste committed to carbon neutral production by 2035 and is working on 80 projects to reduce emissions to achieve this goal.

Getty Images

In the meantime, shipping companies and port operators are trying to reduce emissions through smaller cuts wherever possible, including better-optimized schedules, less idling time and more efficient port infrastructure. It might seem that market forces would have already realized these savings, but improvements in big data, artificial intelligence and electronic hardware have helped to uncover and unlock new opportunities.

"While these methods may seem less drastic and less impactful than shifting to zero-carbon technologies, they are stepping stones to a zero-carbon future," said Alisa Kreynes, program manager for global initiatives at C40 Cities, at VERGE 21. The C40 network works with city governments to address climate change at their ports.

Similarly, aviation has short-term options available that can help nudge the industry towards the high-hanging fruit of complete decarbonization. Hydrogen is one potential candidate to get the job done in the long term, but there’s also a growing category of fossil fuel replacements known as sustainable aviation fuels, or SAF. The advantage of these fuels is that they can be pumped directly into the fuel tanks of existing airplanes, and they’re already being produced today from a variety of feedstocks.

"In order to qualify as SAF and be able to be used in an aircraft, it has to be composed of two components: carbon and hydrogen. Any feedstock that has those two components can technically be used to make SAF," said Pratik Chandhoke, technical services manager for renewable aviation at Neste, a producer of SAF, during an Ask an Expert session at VERGE 21.

In the short term, SAF can be derived from used cooking oil, forest debris, agricultural byproducts or even household trash. However, these supplies are limited, especially considering the amount of material that would be needed for widespread adoption as jet fuel.

"The moonshot to date has been how do we get it to commercialize and scale to serve the volumes that we need," said Erin Cooke, sustainability director of San Francisco International Airport (SFO), at the same Ask an Expert session as Chandhoke. SFO has set a goal for SAF to constitute 5 percent of its fuel supply by 2025.

Another limiting factor is that, for now, SAF can only be used when blended with traditional fossil-based jet fuel, so it ends up comprising 10 to 50 percent of the total mixture, which further reduces the decarbonization potential.

It’s also important to note that any hydrocarbon-based fuel will emit greenhouse gases when burned, but unlike fossil fuels, emissions from SAF could be reabsorbed by new feedstock, enabling a potentially carbon neutral cycle.

Eventually, it might be possible to create SAF out of captured carbon dioxide and green hydrogen, so the supply would be virtually limitless, but like so many other solutions for reaching the high-hanging fruit, the technology isn’t ready yet, and it won’t be for some time.

Like planes, trucks and buses can run on fuel produced from organic waste, specifically renewable diesel. Heavy-duty road vehicles also have the advantage of operating on land in densely populated areas, so they’re suitable for electrification in many cases. Only longer journeys require alternative solutions, such as renewable diesel or hydrogen fuels.

Carbon removal is another option for long-distance road transport. A startup called Remora is on the verge of capturing carbon directly from the tailpipes of semi-trucks, one of only near-term solutions for carbon capture on vehicles.

Who’s taking action?

As with concrete and steel, corporate first movers are setting ambitious goals in hopes of catalyzing new technologies and markets, given that the most promising solutions aren’t yet ready for large-scale deployment.

On the shipping side, Amazon, Unilever, Ikea and six other companies pledged to use exclusively zero-carbon shipping fuel by 2040. In aviation, airlines such as Delta, JetBlue and United are all signing purchase agreements with SAF producers that together add up to billions of gallons of renewable fuel over the next decade.

These commitments are an important step forward, but the current transportation system is designed for fossil fuels. Next-generation solutions often rely on shared infrastructure that is still lacking, such as blending sites for SAF, transport pipelines for hydrogen and bunkering facilities for ammonia.

"The technology is there, but the infrastructure isn’t," said Michael McDonald, operations manager of the Vehicle Innovation Center at bus manufacturer NFI Group, at VERGE 21.

The task of building critical climate tech infrastructure often falls to governments, because individual companies are hesitant to take action independently and get stuck with the bill.

"If we wait for the commercial industry to do it, it’s going to take a long, long time," said Dave Lee, senior account manager at maritime supplier ABB Marine & Ports, at VERGE 21.

I hope that customers really flex their buying power … because we are responsive to our customers, and this is the best way to really drive and amplify this work.

Multiple speakers at VERGE 21 touted California’s Low-Carbon Fuel Standard as a prime example of government policy that has jump-started bold action and new industries. The policy sets strict limits on carbon intensity, but it allows flexibility on how to meet those limits, opening up space for a wide range of solutions. Implementing a similar policy nationwide could help its positive impacts to scale up even further.

In addition to top-down policies, bottom-up pressure also makes a difference.

"The consumer has a lot more power and a lot more influence at stake here than we really have ever had in the past," said Kreynes. "It’s not just up to the individual companies but it’s also up to the individual buyers to have that voice on what happens and how quick we get there."

Customers can drive change by demanding low-carbon shipping options and flight tickets. When consumers ask sharp questions about how their goods (or they themselves) are transported, companies listen and react.

"I hope that customers really flex their buying power … because we are responsive to our customers, and this is the best way to really drive and amplify this work," said Cooke.

Building a stepladder

Across industries, reaching the high-hanging fruit requires a dual temporal focus: There’s a need to operate practically within the realities of the here and now, while also dreaming big about the possibilities for the future.

There may be promising technologies that can theoretically bring emissions down to zero, but none is available at cost or at scale, at least not yet. In the meantime, it’s up to companies, governments and entrepreneurs to take whatever partial steps they can — increased efficiency, reduced demand, greater circularity — while also investing in new technology and infrastructure that can tackle the rest of the challenge later.

The interim measures are like a stepladder, making the high-hanging fruit just a little bit closer, almost within grasp. It might still take a big leap to reach it, but the more we can do now to close the gap, the better chance we have of getting there.

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