Greentown Labs is inviting applications from innovative startups working on CO₂ mineralization and carbonation technologies for construction materials to join Go Build 2026, an accelerator program delivered in collaboration with Amazon and the Global CO₂ Initiative at the University of Michigan.

This initiative is designed to fast-track solutions that can significantly reduce emissions from the built environment, particularly concrete and related materials, while supporting real-world deployment across Amazon’s construction portfolio and the wider building sector.

About the Program

Concrete production is responsible for nearly 8% of global CO₂ emissions, with aggregates representing a largely untapped opportunity for long-term carbon reduction. Go Build 2026 focuses on technologies that permanently store CO₂ through mineralization while maintaining or improving material performance and economic viability.

Selected startups will take part in a structured accelerator that emphasizes testing, validation, and commercialization readiness, working closely with industry experts and Amazon’s technical teams.

Location: Global (with in-person sessions in the U.S.)
Target group: Climate & construction materials startups

What Selected Startups Receive

Participants in Go Build 2026 will benefit from:

• A structured accelerator platform to test and validate technologies in collaboration with Amazon

• A needs-based stipend to support participation

• Technical guidance on performance data collection, economic modeling, and implementation strategies

• Mentorship and partnership-focused programming from Greentown Labs’ climatetech ecosystem

• Exclusive access to Greentown Labs’ and Amazon’s professional networks

• Desk space at Greentown Labs (Somerville and/or Houston) and access to community events throughout the program

Technology Focus Areas

The program is primarily interested in aggregates that utilize waste or anthropogenic CO₂, as well as other construction materials that incorporate CO₂ at the jobsite.

Relevant technologies may include:

• Accelerated CO₂ mineralization processes

• Direct use of flue-gas CO₂ without additional separation

• Advanced particle processing methods

• Products that use CO₂ as a feedstock, additive, or curing agent

Eligible material categories include:

• Concrete aggregates

• Precast concrete products

• Concrete fillers

• Supplementary cementitious materials (SCMs)

• Fiber cement boards, drywall, and insulation

Out of scope are solutions without durable CO₂ storage, short-lived carbon uses (such as fuels), avoided-emissions-only products, or materials that cannot demonstrate long-term (>100 years) performance and safety.

Collaboration with Amazon

Startups will work with Amazon through structured assessments and testing aimed at developing clear pathways for real-world deployment. Areas of collaboration may include:

• Validated technical pathways for CO₂ mineralization

• Performance data from real construction environments

• Commercial-scale economic models

• Integration into existing concrete production facilities

• Quality control, testing, and supply-chain optimization strategies

Tentative Program Timeline

• Kickoff Event: April 1, 2026

• Workshop 1: May 20–21, 2026 (In person)

• Workshop 2: June 24–25, 2026 (Virtual)

• Workshop 3: August 12–13, 2026 (In person)

• Final Showcase: October 1, 2026

Don't miss out on the application deadline which is 9 January 2026.