ETH Zurich-founded carbon capture system producer Climeworks has added $35m to its latest round to fund further business growth.

Climeworks, a Switzerland-based carbon capture technology spinout of ETH Zurich, has closed a CHF100m ($110m) round following a $35m extension backed by undisclosed investors.

The second tranche was secured last month and follows an initial $75m investment from private investors in April 2020 – though that cash injection was only revealed in June.

Founded in 2009, Climeworks markets modular, scalable carbon capture systems used by enterprises and organisations to remove CO2 from the air surrounding their industrial plants in order to offset harmful emissions into the environment.

The technology incorporates a chemical binding to separate carbon from inward ambient air, releasing concentrated CO2 to customers once its filter chamber has been filled.

The additional proceeds will sustain Climeworks’ bid to win more clients by scaling up and optimising its carbon capture technology.

Climeworks has now raised $160m in equity and grant funding to date, including a $1.8m series A round closed in 2011 with state-owned bank Zürcher Kantonalbank (ZKB) and undisclosed additional investors.

The same investors backed a $3.1m series B round for Climeworks in 2014 before returning to invest $30.8m in mid-2018.