Meet Our Members: Introducing Greentown’s Newest Startups of Q1 2024

Twenty-four startups joined our community in Q1 2024, working on innovations ranging from biobased building materials, to sustainable rubber, to solar-powered flight.

We’re thrilled to support these groundbreaking climatetech startups—let us introduce you!


Carbon Negative Solutions is creating smart-city-ready, carbon-negative concrete products. It’s participating in Year 2 of ACCEL.

Hub Controls’ award-winning personal energy-management system, Hub Controller, saves customers money by knowing when their heating and cooling systems need to run—and, more importantly, when they can be turned off. 

Puro Renewables upcycles carbon-negative biowaste to reduce the amount of fossil-fuel-based resin and the carbon footprint associated with typical plastic products. The startup is participating in Go Build 2023.

ZS2 Technologies creates magnesium-based advanced building products that can store up to one-fifth of their weight in CO2 via a proprietary carbon-capture technology. It’s part of the Go Build 2023 cohort.


Active Surfaces develops an ultra-lightweight, flexible solar technology for the built environment. The startup is participating in Go Build 2023, and previously was part of the ACCEL Year 1 cohort.

Arbor is a home-energy advisor that monitors renters’ and homeowners’ energy markets, getting customers the best electric rates in their areas and recommending relevant home-electrification upgrades.

Axis Sky Renewables creates innovative wind solutions, specializing in vertical-axis wind turbines that are less expensive to produce, deploy, and maintain than traditional wind turbines. The startup is part of the second ACCEL cohort.

Smartpipe Technologies’ high-pressure, reinforced-thermoplastic pipeline replacement has a low carbon footprint and built-in leak detection, health monitoring, and intrusion monitoring. The company previously participated in Go Energize 2022, and is now rejoining the Greentown community.


Carbon Upcycling Technologies is a circular-decarbonization solution for hard-to-abate industries—utilizing low-purity industrial CO2 and industrial byproducts to decarbonize cement. The startup participated in Year 2 of the Carbon to Value Initiative and is now part of the Go Build 2023 cohort.

Cellsense develops interactive bio-embellishments that create new possibilities for designers while eliminating microplastics and replacing fossil-fuel-based material at scale. The startup is part of ACCEL Year 2.

EcoForge is a building-material technology company developing affordable, high-performance building materials from local agricultural residues, replacing energy-intensive, fossil-based materials. It’s part of the ACCEL Year 2 cohort.

Endeavor Composites intercepts landfill-destined post-industrial fibers and sustainably repurposes them into semi-finished goods for the composite industry. The startup was part of the Go Move 2022 cohort and is now back for a second Go program, Go Build 2023.

Hempitecture manufactures and distributes biobased building materials, including a low-embodied-carbon insulation. The startup is participating in Go Build 2023.

ONEPREDICT is a digital-solution provider that offers predictive maintenance information with a combination of industrial AI and IoT technologies. Its digital-brain solution, GUARDIONE®, helps reduce downtime, increase facility resilience, and optimize decisions by diagnosing and predicting the status of key industrial assets.

Solidec’s electrolyzer platform captures carbon and manufactures chemicals using only air, water, and renewable electricity—electrifying carbon capture and chemical production at substantially lower capital and energy costs.

Resiliency + Adaptation

AtmoSpark Technologies is an atmospheric-water-generation company with a patented electro-condensation technology, which has a lower energy footprint than that of current water-generation methods. The startup is participating in ACCEL Year 2.

Aquasaic, an ACCEL Year 2 startup, is harnessing biology to clean water for planetary and human health. 

Biosfera converts carbon dioxide into sustainable rubber.

BluBridge Energy Solutions removes carbon dioxide and hydrogen sulfide from pre- and post-combustion gas streams, converting the compounds into inert minerals and significantly reducing the cost and effort associated with transporting and storing the byproducts.

Decimetrix specializes in providing sustainability and energy-efficiency solutions for the energy industry, using data-driven, cloud-based, and AI-powered platforms to help its clients measure, manage, and reduce their carbon footprints.

Element Resources is a project-development company focused on the production of 100 percent green hydrogen. The startup participated in Greentown Go Energize 2022 and is now rejoining the Greentown community.

MicroAvionics is developing innovative levitation technology to enable flight in the mesosphere (50- to 100-kilometer altitudes), using sunlight to generate thrust and eliminating the need for onboard fuel or power.

Sankofa Dynamics creates low-cost, eco-friendly solutions for water, air, and energy problems. It’s part of the ACCEL Year 2 cohort.

Upstream Tech builds software that expands access to environmental data, including remote imagery, global water forecasts, and geospatial data. Upstream Tech is a former member that’s rejoining the Greentown community.