Exploring Carbon-Negative Materials: Autodesk Research’s Path to Net-Zero Buildings

The net zero façade on buildings that form The Phoenix, a 316-unit modular housing development in West Oakland, California.

Our world is warming. Based on data from the UN weather agency (WMO), 2023 was the hottest year that humans have measured—a bleakly fitting capstone to the hottest decade ever. Human activities are the main cause, resulting in excessive concentrations of greenhouse gases trapped within the earth’s atmosphere. Of these gases, carbon dioxide (CO2), which is released during the burning of fossil fuels, is the most prominent. To prevent further catastrophic warming beyond the Paris Agreement’s 1.5°C critical threshold, these emissions must be reduced before 2030.

The building sector contributes a whopping 42% of global greenhouse gas emissions annually (comprising 11% for building materials and 31% for operating buildings). To put that number into context, the aviation industry—which holds a primary spot as a significant polluter in the public consciousness—accounts for a mere 2.5% of global emissions.

It is now beyond critical that the building industry reduce its carbon emissions, or decarbonize. This will require complex rethinking around the way the buildings of the future are designed, constructed, and operated. One of the most critical components of this change will be to determine how to reduce the carbon emitted from the extraction, production, and use of building materials. In part one of this three-part series, we’ll explore how Autodesk Research is accelerating the net-zero transition in the built environment.

Some argue for an approach that more efficiently uses the same old fossil-fuel burning, carbon-emitting materials that have gotten us here in the first place (such as concrete, steel, and glass). While that approach is both worthwhile and necessary, the scaling-up of novel and high-performing materials that sequester more CO2 than they emit, that are carbon-negative, and are viable and easy to use today—not in 10 years’ time—will be far more impactful.

Every year, Autodesk releases a global State of Design & Make report. Based on its findings, this year, more than any other before it, Architecture, Engineering, Construction, and Operations (AECO) and Design & Manufacturing (D&M) companies consider sustainability a vital goal—as well as one of their biggest challenges. In previous years, respondents were more likely to report efforts to decrease waste from production or use recycled materials. Now, as these companies look to the future, many report increased interest in adopting novel sustainability practices. This includes using AI, which was ranked as the number one action companies are taking to be more sustainable.

To better meet the future needs of our customers, Autodesk must not only anticipate the expanded palette of new alternative materials, but also generate the analysis data to feed into AI and digital workflows. As Joe Speicher, Autodesk Chief Sustainability Officer, explains, “Autodesk is dedicated to helping our customers deliver more sustainable outcomes. We do so by integrating sustainability data and analysis in our products, as well as actively supporting research into new material workflows, and promoting collaborations with innovative industry partners to support the decarbonization of the industries we serve.”

The challenge is immense: We must first engineer these materials beyond what has ever been possible, then test those materials in machines that have yet to be built, and finally validate and share our findings for wide accessibility and replicability. Which brings us to Autodesk Research… 

Working with a novel, bio-based material

In a lab coat and surgical gloves, Brian Lee, principal research scientist, Autodesk Research, is gently coaxing living mycelium root, carefully urging the active culture to blend with a mixture of hemp and other agricultural waste inside a long, thin mold. Over the next few days, the mycelium will feed on the hemp, rapidly replicating and growing until it fills the dish and eventually hardens into a solid bar.

At first glance, this disk will resemble Styrofoam in both weight and appearance. But a short while ago it was alive. And now this sample, like hundreds of similar samples before it, will be evaluated in a custom testing rig like the one designed by Allin Groom, senior research scientist, and slowly sheared in half until failure. The outcome of this shear test will offer clues for how to strengthen the next iteration—and provide a wealth of valuable structural data that will be fed into custom material properties in Fusion360.

This is all part of a materials-testing track within a broader initiative at Autodesk Research to explore novel, low-carbon strategies and further net-zero building workflows within the AECO industry. This specific research is exploring ways to reduce carbon emissions in the construction industry now.

Typically, conventional building façade systems include non-sustainable, carbon-intensive layers for insulation, structural performance, and other key properties. But what if we could replace these layers with something with nearly zero carbon emissions? If Brian can successfully double the existing shear strength of the mycelium sample, he will have hit a key structural performance benchmark on the way to potentially replacing the standard layers in a real-world application.

There are other questions and benchmarks along the way: Is the material as durable and long-lasting as traditional insulation? Is it more affordable and faster to install? Is it toxic? Could it also be more “adaptable” in response to climate change? Moreover, how would we even define and prove that with data, much less simulate it?

Our research addresses these and other questions, and as a result, one Autodesk customer will install a net-zero carbon facade panel on The Phoenix, an affordable housing development in West Oakland, California. Because of this, Autodesk Research’s new materials exploration will have directly led to sequestering the carbon equivalent of 63 California Redwoods growing for 50 years.

Now think further into the future: If this single customer were to utilize the same facade assembly in all their new builds over the course of one year in California alone, they would sequester the carbon equivalent of 4,000 acres of dense forest over 50 years. Further still: What if all Autodesk customers, regardless of their skillset or knowledge in sustainable building, designed low-carbon facades and net-zero embodied carbon buildings?

What is carbon?

Every day, every one of our actions emits carbon. When we wake up and turn on the lights (1.6 lbs. CO₂e), when we take a hot shower (3.7 lbs. CO₂e) and make a quick breakfast (2.9 lbs. CO₂e), when we scan the news on an electric device (0.04 lbs. CO₂e), and drive to work (21.3 lbs. CO₂e), and when we heat and cool our homes (5.8 lbs. CO₂e per hour). All these actions emit carbon dioxide (or an equivalent greenhouse gas) into the atmosphere. To quantify effects of these actions, we reduce the complex, environmental impacts into an equivalent, common metric of CO₂e, or “carbon” for short. Low-carbon or “net-zero” carbon strategies include novel processes, materials, and behaviors that mitigate these emissions, and therefore reduce global greenhouse gas effects.

For most of human history, the balance of carbon emissions and carbon storage was in a more or less steady state of equilibrium. But now, as we burn fossil fuels at an ever-growing rate to power our modern lives, that natural cycle is unbalanced—and dangerously out of whack.

Currently, the production of building materials, which relies primarily on fossil fuels, accounts for 11% of global greenhouse gas emissions each year. To address this imbalance in the carbon cycle, it is crucial to reduce carbon emissions and increase carbon sequestration and storage. This can be achieved by adopting renewable energy sources, minimizing the use of carbon-intensive materials, and promoting the utilization of low-carbon and carbon-negative materials.

Foundational carbon concepts 

To fully understand this problem, it’s important to be familiar with specific terminology that describes the movement of carbon through the environment and into materials. 

• Carbon Sequestration: The process by which CO₂ is removed from the atmosphere and stored in a liquid or solid state. This process happens naturally—for instance, when a tree absorbs and stores carbon during photosynthesis. It can also happen as a direct result of new technology, such as direct-air-capture (DAC) fans, which filter CO₂ out of the atmosphere by scrubbing the air, and ultimately storing the CO₂ long term underground or injecting it into building materials such as concrete.

• Carbon Dioxide Removal (CDR): Technologies, practices, and approaches that remove and durably store CO₂ from the atmosphere. CDR encompasses a wide array of approaches, including DAC coupled with durable storage; soil carbon sequestration; biomass carbon removal and storage; enhanced mineralization; ocean-based CDR; and afforestation.

• Embodied Carbon: The upfront carbon emissions associated with all activities related to the creation of a material or product. Only recently have we been able to measure embodied carbon. Since the Industrial Revolution, we have been dependent on fossil fuels to create materials such as aluminum, steel, and cement, all of which result in excessive carbon emissions to manufacture. Materials with low embodied carbon—such as wood, mycelium composites, and bio-cements—utilize renewable energy sources and less energy overall to produce.

• Carbon-Negative Materials: Materials that sequester more carbon than was emitted during their production. For example, timber may sequester more carbon during the process of tree growth than is emitted during the processes of cutting the tree, transporting it, and milling the lumber. But the calculation can be complex. It must account for the biogenic carbon that was sequestered and stored in the tree’s biomass and may depend on whether a new tree is planted when the original tree is cut down. The duration of carbon storage is also important. If left unprotected, wood can decompose within a decade, releasing the stored carbon back into the atmosphere. By maintaining and preserving carbon-negative materials we can extend their lifespans and lock away carbon for hundreds or thousands of years.

• Bio-based materials: A class of materials derived from living organisms, including plants, animals, and fungi. Bio-based materials have a much lower environmental impact than materials that are petroleum-based or require fossil fuels to be produced. Innovative bio-based materials, such as mycelium composite, require little energy to produce and utilize waste streams that store carbon in their plant-based fibers, resulting in a low or even negative embodied carbon. Using more bio-based materials, like mycelium composite, timber, cork, and bioplastics, can help us reduce the embodied carbon in buildings. 

• Cradle-to-Grave versus Cradle-to-Cradle: Cradle-to-grave (C2G) is a concept that describes the lifecycle of products in our current linear economy, going from raw material extraction, production, use, to disposal. A paradigm shift from C2G, Cradle-to-cradle (C2C) is a framework, and product standard to assess and enable more safe, sustainable, and circular products lifecycles. Regarding carbon emissions, C2C materials have more circular lifecycles with minimal waste and higher rates of recycling/reuse, resulting in a significantly lower environmental impact. For example, recycled aluminum emits 94% less carbon than aluminum produced from raw materials. Reusing carbon-storing materials such as wood, helps lock away carbon for as long as it doesn’t decompose, resulting in a lower embodied carbon where it is reused and reducing the need for more raw materials.

• Environmental Product Declaration (EPD): A standardized report which communicates the environmental impact of a product over its full life cycle. This transparent, third party-verified document includes resource usage, emissions, and waste generation, allowing consumers and business to make informed decisions based on the product’s environmental performance. EPDs are used to compare the environmental footprint of different products and support decision making between conventional and more sustainable materials.

Figure 2: The steps for producing a carbon negative mycelium composite core from ingredients on the left to finished product on the right.

Exploring the potential of carbon-negative materials

This research is about more than a single bespoke biomaterial prototype. Mycelium is one of many carbon-negative, bio-based materials that our team within Autodesk Research is excited to be working with. While the use of mycelium is valuable to demonstrate what is possible now, in a very tangible, real-world application, the focus and resulting opportunities of this research extend far beyond any one material.

As the Autodesk State of Design & Make report reveals, AECO companies are enthusiastic and ready to begin using an updated palette of available materials. However, real-world examples of innovative alternative materials these companies could draw from are still frustratingly few and far between. Filling that gap has the potential to drive sustainable impact and help address excessive emissions throughout the industry. This is only the beginning for widespread utilization, the first step in proving the validity of seemingly implausible net-zero materials through real-world demonstrations and spreading the results to our industry partners via generalized digital workflows.

When we explore a novel material’s potential, we must first study it both holistically and empirically—its function, shape, and manufacturing processes all in relation to the proposed design application. “We have to make and test the materials to truly understand their behavior,” says Andy Harris, senior manager, Autodesk Research, whose focus is on materials science. “The tests can be as simple as scratch tests to understand how well a new floor in a train station will hold up over 50 years, or they could be simulated accelerated aging tests of temperature swings and extreme weather conditions to see how a façade can cope with various events that will occur over its lifetime.”

To demonstrate this, the Autodesk Technology Centers have developed specialized testing equipment that mimics a variety of natural conditions, from wind and rain to intense heat and cold. We can re-create a scorching summer day complete with intense sunlight using UV radiation—an urgent real-world concern as UV rays rapidly degrade some bio-based materials. These tests provide valuable insights for improving a material’s durability in order to meet the requirements for real-world applications.

This testing process naturally flows into a software-focused, data-rich application, as Andy explains: “The decision-making process is very challenging and highly dependent on data. This only gets more complex as you scale up to the size of a building, and these individual materials form systems of much larger assemblies. Material assemblies have to be a bigger part of future digital workflows so that the engineer can balance each candidate material with different performance metrics, sustainability criteria, and cost requirements. This is where we need to push to have an impact on industry.”

The resulting data from this research sheds light on the myriad ways we can advance and expand materials in AECO. It also gives our industry partners valuable new tools. Our customers are eager to find sustainable building solutions and this data enables informed decision making so they can meet their own low-carbon goals, promising better outcomes for their missions—and for ours.

Scaling a breakthrough

Back in Brian’s testing lab, mycelium sample 65 doesn’t look like anything particularly special. To the naked eye, there is nothing to distinguish it from the preceding 64 samples. It’s just another unassuming prototype, numbered, tagged, and dropped among a collection of others exactly like it.

But this one has a crucial difference.

Brian grew sample 65 under continuously applied hydraulic pressure. The hope was that this additional pressure would lead to a higher material density, meaning that the mycelium fungal roots would bind with the hemp substrate in a denser—and ideally stronger—arrangement than ever before. Coming out of the press it immediately felt heavier and more substantial in hand, and after using the testing rig to shear sample 65 to failure it was confirmed: this sample was nearly 10 times the strength of the existing baseline and would now be structurally competitive with the industry-standard fossil-fuel based Extruded Polystyrene (EPS) insulative foam.

This breakthrough provides the crucial material data that now flows into Fusion360 simulation software, and our engineering partners validate its structural performance. Finally, this carbon-negative biomaterial is ready to become part of a facade for a real-world building.  What once only existed in a petri dish, can now be scaled-up and tested on a full-size, factory-built facade panel. With traditional insulation every square foot of this facade panel would emit 7.1 lbs. CO₂e. Now, it will store more carbon than it emits, it is better than net-zero embodied carbon.

To create this first-of-its-kind facade, the “enhanced” mycelium is grown into a series of convex molded patterns, and then sandwiched between two fiberglass shells. This composite brings together the carbon sequestration of mycelium materials with the durability of fiberglass as a “drop-in” facade system. It can be built with today’s building codes and construction processes. It is ready to be used now. And in the future, it can become even more sustainable, by replacing fiberglass with low-carbon basalt or plant-based bio-resins.

Figure 5: Integrating mycelium bio-material and fiberglass as a first-of-its-kind carbon-negative facade system.

Now the process begins again, only on a much grander scale: Working alongside a dedicated cross-disciplinary team of architects, engineers, and fabricators, the researchers continue testing for exact carbon footprint, cost, constructability, fire resistance, sound reduction, and thermal performance, all to ensure that examples exist for our customers to make informed decisions when choosing low-carbon material solutions.

The initial prototype resulting from those efforts is now being installed on one an affordable housing unit at The Phoenix: a single, 12×38-foot carbon-negative facade panel that stores the equivalent of 1,800 lbs. of CO₂e, or the heating load equivalent to 1.3 years of hot showers for the average person. It’s a hopeful step toward one day achieving total net-zero building.

And it all started as humble sample 65.

In the next post, we’ll explore how Autodesk Research is leading by example in moving the needle on decarbonization today.