Sublime Systems

Sublime Systems is a Somerville, Massachusetts-based company rethinking how cement is made. Its technology produces Sublime Cement®, an industry-accepted alternative to ordinary Portland cement (OPC) for concrete. Rather than relying on the energy-intensive kiln used in conventional production, the process uses targeted electrochemistry at ambient conditions. Sublime says this approach can reduce production energy use by 30% to 40%, avoid emissions of carbon dioxide and other pollutants, and turn a wide range of rocks—including some industrial solid waste—into cement while co-producing pure minerals.

The company presents Sublime Cement as cleaner, more durable, and whiter than conventional cement, with potential benefits that include reduced urban heat island effects when used outdoors. It is designed for use in concrete across a range of applications, from polished interiors to demanding exterior environments. Sublime has deployed its cement in real-world projects since 2023 and is scaling production, with plans for a kiloton-scale plant and future megaton-scale manufacturing.