Houston claimed the No. 1 spot among the 50 most visited in the U.S. with the lowest carbon footprint. Sean Pavone/Getty Images

People looking to travel to a sustainable city probably don’t have Texas spots at the top of their lists. Images of oil, cars, and blasting air conditioners spring up. The Texas power grid, no one need remind us, is barely hanging on.

But Texas blew other states away for lowest carbon footprint per capita, landing Houston at the top of the 2022 list compiled by travel blog Park Sleep Fly. Austin followed (No. 3), then San Antonio (No. 4) and Dallas (No. 9). Only Florida appeared twice in the top 10, and none matched Texas with four cities.

Among the 50 most visited in the U.S., those with the lowest carbon footprint are:

1. Houston
2. Los Angeles
3. Austin
4. San Antonio
5. Tampa, Florida
6. Salt Lake City
7. Phoenix
8. Miami
9. Dallas
10. Portland, Oregon

Houston is not exactly a green place, with less-than-ideal utilization of public transportation. It and Dallas tied for third place among least sustainable cities in the same report.

“Public transit isn’t the most popular mode of transportation in Houston, but it does exist,” an online publication called TripSavvy drably admits. The city takes credit for employing “nearly one third” of the nation’s oil and gas extraction workers.

On the renewable side, however, Houston claims more than 100 solar energy companies, and at least half of its corporate research and development centers pursue “energy technology and innovation.” And its huge population spreads the load, leaving only 14.6 metric tons of carbon dioxide per resident — the same as Los Angeles. Big cities seem to have an advantage in this rating system.

Austin is just behind Houston at 15 metric tons per capita, neck-and-neck with San Antonio at 15.2. These two cities have smaller populations to distribute their total footprint, but are generally seen as eco-friendly. Austin got a big head start in 1991 with the introduction of the Austin Energy Green Building program — the first of its kind in the whole country — which created an evaluation system for individual building sustainability that’s still in use. Dallas' carbon footprint is the largest of the Texas cities in the ranking, at 16.5 metric tons per capita.

As such a multifaceted issue (especially tied up in economic concerns), sustainability is hard to pin down from city to city. The multiplicity of this list is yet another indicator that Texas as a whole is a much more nuanced place than many people think.

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This article originally ran on CultureMap.

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Houston energy transition hub opens applications for new fundraising cohort

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EnergyTech Cypher has opened applications for its second Liftoff fundraising program.

Applications close May 20 for the 10-week virtual fundraising sprint. The program is geared toward energy and climatech founders preparing to raise their first institutional round. It will cover fundraising requisites, like pitch materials, term sheet negotiation and round closing, according to a release from EnergyTech Cypher.

The program kicks off June 1 and runs every Monday from 1-3 p.m. CST. It will conclude with an in-person capstone simulation in Houston on August 3, where founders will work to close a mock round.

Jason Ethier, EnergyTech Cypher founder and CEO, will lead the program with Payal Patel, an EnergyTech fellow and entrepreneur in residence.

The program is available through Cephyron, EnergyTech Cypher's new investor relationship management platform, built specifically for energy and climatech founders. Users must have a Cephyron Boost membership to participate in the Liftoff program.

The Cephyron IRM app recently went live and is available to founders at any point in their fundraising process, according to the news release. The platform aggregates investor data, tracks market signals and delivers curated weekly recommendations.

EnergyTech Cypher launched Liftoff last year. The inaugural cohort included 19 startups, including Houston-based AtmoSpark Technologies, The Woodlands-based Resollant and others. Each participant closed at least one fundraising deal, according to EnergyTech Cypher.

EnergyTech Cypher rebranded from EnergyTech Nexus earlier this year. It also launched its CoPilot accelerator in 2025. The inaugural group presented its first showcase during CERAWeek last month.

EnergyTech Cypher's annual Pilotathon Pilot Pitch and Showcase applications also opened this month. Find more information here.

Houston climatech startup raises $29M funding round​

fresh funding

Houston-based NanoTech Materials has closed a $29.4 million Series A.

The round was led by Austin-based HPI Real Estate & Investments. Houston-based Goose Capital and Austin-based Milliken & Company also participated.

Nanotech has developed its patented Insulative Ceramic Particle (ICP) technology, which reduces heat transfer in buildings and outdoor infrastructure, improving efficiency and safety. It's known for its Cool Roof Coat, Wildfire Shield and Insulative Coat: Cool Touch product lines.

With the new funding, Nanotech plans to scale operations and expand its market reach for its products.

“We’re addressing one of the pressing and urgent challenges facing infrastructure owners today: controlling energy costs and extending asset life,” Mike Francis, CEO and co-founder of NanoTech Materials, said in a news release. “This financing marks a transformative moment for us. It allows us to rapidly scale production and bring our high-performance materials to market faster, while delivering measurable cost savings and redefining what resilience looks like in today’s built environment.”

Nanotech launched in 2020 and was the first company selected for Halliburton Labs. It moved into a 43,000-square-foot space in Katy in 2023. It brought on new partners that expanded the company's reach in the Middle East and Singapore the following year. Its technology was recognized as one of Time magazine's 200 Best Inventions of 2024.

“We were early investors in Nanotech Materials and are pleased to continue supporting the company as it becomes a leader in breakthrough materials science and technology,” John Chaney, investor at Goose Capital and board member at NanoTech, added in the release. “NanoTech’s ability to elevate fire resilience and energy efficiency in the built environment is critical for strengthening and hardening infrastructure. Its pioneered approach is transforming current building standards and making our lives safer.”

The company has secured $34.4 million in total to date, according to the release. It raised an oversubscribed funding round in 2023 and a $5 million seed round in 2020.

Houston clean energy startup acquired by battery storage company FlexGen

m&a activity

A North Carolina company has acquired Houston-based Clean Energy Services, a provider of services for battery energy storage systems and utility-scale solar, for an undisclosed amount.

The buyer is Durham, North Carolina-based FlexGen Power Systems, a provider of battery energy storage software and services.

Clean Energy Services (CES), whose offices are at the Ion, will operate as a subsidiary of FlexGen. Existing CES customers will continue to receive services from CES without disruption or change, FlexGen says.

“Demand for reliable, high-performance power is accelerating, and customers need partners who can deliver at scale,” Kelcy Pegler, CEO of FlexGen, said in a news release. “The addition of CES strengthens our service platform and reinforces our leadership in energy storage technology.”

Ahmad Atwan and Constantine Triantafyllides co-founded CES in 2022. As a startup, CES had raised $8 million in venture capital, according to PitchBook.

“CES has achieved a market leadership position in battery storage services by focusing on reliable speed of service delivery and optimizing asset performance,” Atwan, the company’s CEO, added the release. “FlexGen and CES have been strong partners for years, and this transaction enables us to deliver more robust solutions across a complementary set of customers and markets.”

CES will continue to operate its remote operations center in Houston for over 1 gigawatt of solar assets and 4.5 gigawatt-hours of battery assets, while FlexGen will maintain its remote operations center in Durham.