The idea that buildings should be constructed with an eye to slowing climate change by making them carbon neutral is being superseded by the development of even more ambitious technologies that aim to remove CO2 from the atmosphere, making them carbon negative. CO2 is the main component of greenhouse gases, which cause global warming.
The Department of Energy is incentivizing work in this field, announcing this week that it is funding 18 projects that will rely on newly developed technologies that can convert buildings into carbon storage structures.
Ten universities and eight national laboratories and private companies have been awarded $39 million to develop clean energy building materials that remove carbon from the atmosphere and demonstrate carbon negative whole-building designs.
The teams, led by DOE's Advanced Research Projects Agency-Energy (ARPA-E) and selected under the agency's Harnessing Emissions into Structures Taking Inputs from the Atmosphere (HESTIA) program, will prioritize overcoming the key obstacles facing carbon-storing buildings: scarcity, expense and geographically limited building materials.
The 10 universities that received the grants are employing different approaches to drawing CO2 from the air: Texas A&M University and the University of Pennsylvania will use 3D printing to its advantage, creating net-carbon-negative building designs with hempcrete—a lightweight material mixed with the hemp plant's core and lime—and carbon-absorbing funicular floor systems, respectively. Other universities — Clemson University and University of Wisconsin-Madison, among other organizations — are planning to create carbon-negative replacements for wood, cement, and insulation.
With projects like these, the program hopes to meet their decarbonization goals by increasing the total amount of carbon stored in buildings, creating "carbon sinks"—which are sites that absorb more carbon than they produce.
While it is unclear just how much carbon the new building materials will absorb, their plant mixtures are designed to employ direct air capture, sequestering CO2 from the air and storing it within their layers. For instance, at the University of Colorado Boulder, the developing technology plans to produce biogenic limestone, which will use coccolithophores—or calcareous microalgae—to suck in and retain CO2 in mineral form by way of photosynthesis and calcification.
As it stands currently, many buildings around the world are the opposite of carbon sinks. They're "carbon sources," meaning that they release carbon into the atmosphere, effectively making the building and construction sector one of the notable producers of greenhouse gases.
Globally, the share of energy-related CO2 emissions from this sector when compared to other sectors was at 37%in 2020, according to the 2021 Global Status Report for Buildings and Construction published by the UN Environment Programme. In the United States, the greenhouse gas emissions produced by the sector in building manufacturing and construction, renovation, and disposal accounts for 10%of total annual emissions.
"There's huge, untapped potential in reimagining building materials and construction techniques as carbon sinks that support a cleaner atmosphere and advance President Biden's national climate goals," said U.S. Secretary of Energy Jennifer M. Granholm. "This is a unique opportunity for researchers to advance clean energy materials to tackle one of the hardest to decarbonize sectors that is responsible for roughly 10% of total annual emissions in the United States."
The Energy Department says the greenhouse gas emissions produced by the materials currently used are "concentrated at the start of a building's lifetime." This compounds the urgency of tackling national environmental challenges, since the latest United Nations' World Meteorological Organization report shows that the concentration of three greenhouse gases in particular—carbon dioxide, nitrous oxide, and atmospheric methane— rose even more in 2021 after reaching new highs in 2020.
ARPA-E's announcement is the latest action by the agency to reflect President Biden's plan to reach zero emissions by 2050.
Earlier this year, ARPA-E also awarded $5 million in funding the work of two universities— the University of Washington and University of California, Davis — to design assessment tools and frameworks for transforming buildings into carbon storage structures.
HESTIA was created in 2021 to develop building materials and designs that specifically remove carbon during the building production process and store it in the finished product's chemical structure.