How MassCEC Supports The Reduction of Embodied Carbon

On April 22, 2020, Earth Day, Governor Charlie Baker formalized that the Commonwealth’s new greenhouse gas emissions limit would be net-zero by 2050. In the fight against climate change, Massachusetts needs to reduce greenhouse gas (GHG) emissions from a variety of economic sectors. MassCEC aims to reduce the carbon contributions of each of these sectors through clean energy funding opportunities, and one of the major focal points of these programs is building decarbonization. Building materials and construction currently account for about 11% of global CO2 emissions. A major driver of emissions in this sector is embodied carbon, which is the sum of all GHG emissions resulting from the mining, harvesting, processing, manufacturing, transportation, and installation of building materials.

Even if a building is energy efficient, it can still have embodied emissions that adversely affect the climate. Antiquated environmental impact analyses did not inspect such emissions- a serious oversight considering, globally, embodied carbon from construction accounts for approximately 3,729 million metric tons of CO2 annually. At construction’s increasing rate, embodied carbon will continue to rise until it is responsible for nearly half of new construction emissions during the period 2020-2050. This formidable annual emissions projection can be mitigated by selecting eco-conscious construction materials going forward. 

Concrete

As the most widely used construction material in the world, concrete production is expected to rise 12-23% by 2050, which is cause for concern considering how harmful concrete processing can be. Emissions are released at two stages in the concrete production process: 40% of the CO2 generated is from the burning of fossil fuels, and the remaining 60% is from naturally occurring chemical reactions. See our blog “Could Buildings Become A Solution to Global Warming? Addressing the Impacts of Embodied Carbon” for further details about GHG emissions in concrete manufacturing.

In 2019, MassCEC awarded Dr. Nima Rahbar from Worcester Polytechnic Institute a $65,000 Catalyst grant for his Enzymatic Self-Healing Concrete proposal. Professor Rahbar’s technology enables concrete to be more resilient against wear through its regenerative qualities. The concrete “self-heals” using a carbonic anhydrase enzyme, which catalyzes calcium carbonate crystal precipitation and repairs concrete to its original strength by plugging the flaws. The concrete reduces carbon consumption mainly by mitigating the need for further concrete production to repair or replace existing worn concrete. It also actively reduces ambient GHGs by consuming CO2 during the enzymatic chemical reaction. Not only is the enzymatic self-healing concrete environmentally beneficial – but it is also inexpensive and economically viable as well. Professor Rahbar’s concrete technology does not pose any risk to human health because the enzyme is both non-toxic and biodegradable. Recently, the enzymatic self-healing concrete has been patented and is in its final stages of testing in the Catalyst program. 

Insulation

The insulation of a building is crucial for two reasons. First, it is the barrier between the thermal energy internal and external to the building, therefore, its effectiveness determines the amount of energy required to heat or cool the building. Second, insulation can act as a contributor to the embodied carbon of the building, or as a carbon sink - the difference lies in the materials. Using natural materials and blown-in installation are the best ways to reduce the footprint of insulation.

The insulation of a building is crucial for two reasons. First, it is the barrier between the thermal energy internal and external to the building, therefore, its effectiveness determines the amount of energy required to heat or cool the building. Second, insulation can act as a contributor to the embodied carbon of the building, or as a carbon sink - the difference lies in the materials. Using natural materials and blown-in installation are the best ways to reduce the footprint of insulation.

Natural materials, such as wood, act as a carbon sink, a material that absorbs carbon from the environment. While embodied carbon is a crucial consideration, it should be balanced with the operational performance of the insulation, because energy loss due to lack of effectiveness in containing thermal energy will inherently result in increased carbon emissions. 

In 2015, MassCEC awarded CleanFiber (formerly Ultracell Insulation) an InnovateMass grant of $150,000 to promote their Advanced Cellulose Insulation proposal. CleanFiber’s project creates a method for producing cellulose insulation from 100% recycled cardboard and paper production waste. This insulation acts as a carbon sink because the cardboard and paper are harvested from plants that remove CO2 from the atmosphere. Instead of using a product that has an emissions-intensive production process, the cellulose insulation uses existing materials that remove and retain carbon from the atmosphere. CleanFiber’s insulation is also priced competitively with fiberglass and foam insulation due to their energy efficient production process.

Steel

Steel is used in a variety of different industries, but two of the main ones are the buildings and transportation sectors. In buildings, steel is used for the frame, reinforcing bars, and sheet products. In transportation, steel is used for mechanisms such as vehicle engines and freight trains. As such, steel production is another major embodied carbon contributor in the building materials sector.

A way to reduce the overall amount of embodied carbon contributed by steel in construction and transportation is to avoid using it altogether, when another less-emitting material will suffice. But, a more sustainable alternative to steel, particularly in the transportation sector, is aluminum. Due to aluminum’s relatively low weight, it has a much lower embodied carbon impact than steel through decreased transportation and energy costs.

MassCEC has awarded several transportation-related, aluminum-based projects, including Alloy Enterprises’ 2020 proposal to the Catalyst program. Alloy’s Enterprises’ additive manufacturing technology aims to lower both the cost and timescale of printing aluminum parts, thus enabling more rapid innovation, particularly in the light-weighting of airplanes and automobiles. Alloy Enterprises’ product combines laser cutting with a novel metallic bonding process to create a 3D printing process for aluminum parts. The 3D printing machine uses aluminum foil instead of the typical metal powder, resulting in improved safety, decreased energy intensity in manufacturing, and lower costs. Presently, a lack of rapid fabrication technologies to enable iterative prototyping and testing is a barrier to greater adoption of aluminum as a structural material.

Another project MassCEC awarded that focuses on the development of aluminum is 2020 AmplifyMass grantee Veloxint Corporation. Veloxint is developing and industrializing next-generation nanocrystalline metal alloys for advanced manufacturing and light-weighting in aerospace. Together with General Electric, Oak Ridge National Laboratory, and the University of Kentucky, Veloxint will demonstrate lightweight engine compressor blades made with a proprietary Veloxint alloy that enables substantial improvements in the fuel efficiency of commercial aircrafts. By progressing the applicability and lightweight nature of aluminum, both Alloy Enterprises and Veloxint mitigate barriers to accessing lower embodied carbon alternatives, such as aluminum.

Looking Forward

Although projections for carbon emissions appear dire in the face of the climate crisis, many alternatives to traditional high embodied carbon materials are beginning to emerge and some of these material options provide the ability to sequester carbon when constructing and remodeling buildings. Environmental change is a necessity for the future of human life, and it begins with large-scale alterations to the choices we make. While buildings and modern transportation are an integral aspect of developed society, it is possible to change the way we construct and reconstruct with embodied carbon in mind so that our buildings and vehicles can be more efficient and climate-conscious than ever. The challenge we are tasked with is imminent and complex – but MassCEC hopes to be a part of the larger solution by funding promising green energy and building systems to achieve the Commonwealth’s climate goals.