Concrete is a time-tested construction standby, but the production of the key ingredient, cement, creates a massive amount of CO2 emissions.
Cement manufacturers in recent years have begun to offset cement’s high electric and coal-fired consumption with other, bio-based sources. Plants are using from 5% to 20% alternative fuels, for example.
Some cement makers are innovating production to make it more sustainable. For instance, Calera has developed a process to collect 50% of the CO2 emissions from the cement-production process and use it to produce a new type of cement.