Microsoft is building 120 new data centers this year alone, and operates more than 300 of the server hubs worldwide. The facilities require significant amounts of concrete, which is a big source of carbon emissions. Numbers vary, but one estimate pegs concrete used in construction as being responsible for 8% of global greenhouse gas emissions.
While the tech juggernaut expands, it also aims to be climate negative by 2030.
So the Redmond, Wash.-based company is acting as a guinea pig and testing greener alternatives to conventional concrete. This summer at the building site of a new data center in Eastern Washington, Microsoft had its contractors pour three different mixes for sidewalk slabs, including concrete made from materials produced by marine algae and another containing waste from coal burning and steel manufacturing. The alternatives can cut the concrete’s carbon footprint in half, according to the company.
“It will allow us to see with our own eyes that this material can hold up over time.”
– Sean James, senior director of data center research for Microsoft
“It will allow us to see with our own eyes that this material can hold up over time,” Sean James, senior director of data center research for Microsoft, told GeekWire.
Concrete is one of the most widely used building materials on the planet, so the hope is that solutions emerge quickly and can be ramped up and adopted widely.
Earlier this year, Microsoft, Amazon Web Services (AWS), Google and Meta signed an open letter calling on the tech sector to use less concrete and lower-carbon materials in the construction of data centers. The greener alternatives are often more expensive, at least for now, so it can be easier for tech giants with deeper pockets to pay a premium for the concrete.
Conventional concrete is a mix of cement, water, rocks and sand. The cement is the culprit for the carbon emissions. It’s usually made from limestone that’s been super heated, requiring lots of energy to reach the high temperatures and producing carbon dioxide as a byproduct of the process.
Two of the mixes tested in the Eastern Washington town of Quincy included a so-called “biogenic” limestone provided by a startup called Minus Materials. The company is using technology developed at the University of Colorado at Boulder that harnesses carbon-consuming microalgae from the sea for producing limestone.
At an earlier pilot project in Phoenix, Microsoft used a recycled glass product called “ground glass pozzolan” to replace some of the cement incorporated into a concrete mix used at a data center. The substituion was successful, and Microsoft engineering teams are trying to incorporate the glass into datacenter builds, but the product has limited availability.
Microsoft is also collaborating with Blue Planet, a startup that turns CO2 into a rock material, to test its product in concrete. The company is looking for ways to help Blue Planet scale its operations.
In addition to testing and purchasing greener materials, Microsoft is also investing in startups developing lower-carbon construction materials through its $1 billion Climate Innovation Fund.
Microsoft is backing Prometheus Materials, a startup also using limestone-producing microalgae, and both Microsoft and Amazon are investing in CarbonCure, which removes carbon from the atmosphere and chemically traps it in concrete. Amazon is also an investor in Brimstone, which swaps limestone for carbon-free calcium silicate rock.
Microsoft and Amazon are likewise writing checks to startups developing green processes for manufacturing steel, another essential construction material with a big carbon impact.
Time is of the essence in making the switch to cleaner practices as the path to holding global warming to 1.5 degrees Celcius gets increasingly narrow, according to the International Energy Agency.
Brandon Middaugh, senior director of Microsoft’s Climate Innovation Fund, said that greener concrete is getting closer to cost parity with conventional concrete, and there’s hope the foundational material can dramatically shrink its carbon footprint.
“I’m really optimistic,” Middaugh said, “that we can get to net zero, or even carbon negative concrete.”