Constellation and Calpine's $26B clean energy megadeal clears final regulatory hurdle

big deal

Houston's Calpine Corp. will be acquired by Baltimore-based nuclear power company Constellation Energy Corp. Photo via DOE

Baltimore-based nuclear power company Constellation Energy Corp. received final regulatory clearance this month to acquire Houston-based Calpine Corp. for a net purchase price of $26.6 billion.

The acquisition has the potential to create America’s “largest clean energy provider,” the companies reported when the deal was first announced in January.

The Department of Justice approved the acquisition contingent on Calpine divesting several assets, including one in the Houston area.

The company agreed to divest the Jack Fusco Energy Center natural gas-fired combined cycle facility in Richmond, Texas; four generating assets in the Mid-Atlantic region; and other natural gas plants in Pennsylvania and Corpus Christi, Texas.

The Federal Energy Regulatory Commission, the Public Utility Commission of Texas and the New York Public Service Commission previously approved the deal. The companies can move toward closing the acquisition once the court finalizes the stipulation and order.

"We are very pleased to reach a settlement that allows us to bring together two magnificent companies to create a new Constellation with unprecedented scale, talent and capability to better serve our customers and communities while building the foundation for America’s next great era of growth and innovation," Joe Dominguez, president and CEO of Constellation, said in a news release. "We thank the Department for its professionalism and tireless work reviewing this transaction through these many months. It’s now time for us to complete the transaction, welcome our new colleagues from Calpine, and together begin our journey to light the way to a brilliant tomorrow for all."

Andrew Novotny, CEO of Calpine, will continue to lead the Calpine business and Constellation's fleet of natural gas, hydro, solar and wind generation, according to the company. He will report to Dominguez and also serve as senior executive vice president of Constellation Power Operations.

Constellation is considered one of the top clean energy producers in the U.S. Earlier this month, the company was approved to receive a $1 billion loan from the Department of Energy's Energy Dominance Financing Program to restart its 835-megawatt nuclear reactor in Pennsylvania known as Crane Clean Energy Center.

"Work to restart the reactor comes at a time of unprecedented electric demand growth from electrification and the new data centers needed to support a growing digital economy and to help America win the AI race," a news release from the company reads. "Crane will support grid stability by delivering reliable, around-the-clock electric supply."

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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.

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