Which Defence Companies Are Investing in Energy Technologies?

Last updated: September 25, 2026

A growing number of established defence contractors and aerospace suppliers now run energy businesses alongside their military work — building small modular reactors, supplying microreactor fuel, expanding grid technology, or manufacturing batteries for both soldiers and civilian storage markets. This page, part of The Daily Energy’s Energy & Defence coverage, tracks which defence-linked companies are genuinely active in energy, what they are building, and where that technology shows up outside the military. It excludes companies whose only connection to energy is being a customer (a base that buys electricity) rather than a builder, investor or technology supplier.

Why Defence Companies Are Moving Into Energy

Three forces are pulling defence and aerospace companies into energy markets. First, militaries themselves are large energy buyers under pressure to cut fuel convoys and harden base power — the U.S. Department of War’s push for 14-day installation energy self-sufficiency and its Janus nuclear microreactor program, showcased at the Pentagon’s September 2026 Energy Innovation Expo, are direct examples, creating government contracts that reward companies with reactor, storage or microgrid expertise. Second, several nuclear-capable defence suppliers (naval reactor builders, fuel fabricators) already hold the licensing, security clearance and manufacturing base needed for the civilian small modular reactor (SMR) and microreactor boom, so entering civilian nuclear is a natural extension rather than a new business. Third, aerospace and industrial conglomerates with large addressable engineering divisions have found that data-center power demand, grid modernization and energy storage are simply bigger, faster-growing markets than defence alone.

Nuclear Power: The Biggest Overlap

Nuclear energy is where the defence-to-energy crossover is most concrete, because many of the same companies that build naval reactors or reactor fuel for submarines are now building SMRs and microreactors for civilian and military-installation customers.

These five companies illustrate a pattern: naval and defence-nuclear expertise (Rolls-Royce, BWXT) sits alongside newer entrants that won defence contracts specifically because of civilian nuclear capacity already being built (General Atomics, Westinghouse), plus at least one company, GE Vernova, whose nuclear push is separate from its aerospace sibling’s military engine business but shares a corporate lineage.

Aerospace and Industrial Conglomerates: Honeywell’s Energy Business

Honeywell runs a dedicated Energy and Sustainability Solutions segment alongside Aerospace Technologies, Building Automation and Industrial Automation. In March 2026, Honeywell Aerospace signed a supplier framework agreement with the U.S. Department of War that includes a $500 million multi-year investment to expand production capacity for defence technologies — a defence-side commitment running in parallel with its energy business, rather than a merger of the two. Honeywell’s energy unit focuses on digitally optimized industrial and utility operations rather than reactors or generation hardware, making it a software- and controls-oriented player rather than a hardware builder in this space. The company is also separating its Aerospace division onto Nasdaq (ticker HONA) in a process expected in 2026, which will formally split the aerospace-defence business from the rest of Honeywell, including Energy and Sustainability Solutions.

Shipbuilders Diversifying Into Offshore Energy

European and U.S. naval shipbuilders are using the same yards, welding capacity and specialised-vessel expertise built for warships to enter offshore wind and other marine energy construction. Fincantieri, Italy’s largest shipbuilder and a major naval contractor, set a 2026-2030 business plan targeting more than €50 billion in new orders while expanding both its defence shipyards and its offshore segment — including cable-laying vessels, offshore wind support ships and oil-and-gas marine engineering. One concrete example: an 88-meter service operation vessel built at Fincantieri’s Bay Shipbuilding yard is entering service in 2026 to support Dominion Energy’s Coastal Virginia Offshore Wind project. Other major naval shipbuilders, including BAE Systems and Naval Group, compete in the same broad offshore and marine-engineering markets, though public reporting on the scale of their non-defence offshore energy work is more limited than Fincantieri’s disclosed plan.

Turkey’s ASPİLSAN Enerji: Military Batteries Meet Civilian Storage

ASPİLSAN Enerji is Türkiye’s state-linked battery and power-electronics manufacturer, supplying lithium-ion cells and battery packs for military radios, robotic and weapon systems, and naval and aviation platforms. Its newest cell, the A35 — a rechargeable 18650-format lithium-ion cell using a silicon/graphite composite anode — was launched at the SAHA defence-industry expo and later shown at CES 2026 alongside the company’s broader “Power Beyond Boundaries” energy-storage lineup. ASPİLSAN is also developing fuel cells (PEM, DMFC and DEFC types) across a stated 50W-to-100kW range for both military and civilian use. The company’s dual military/civilian product line makes it one of the clearest working examples of a defence battery manufacturer building directly toward civilian energy-storage and fuel-cell markets.

Where This Technology Is Used in Civilian Energy

The overlap is concentrated in three technology areas. Nuclear: the SMR and microreactor designs Rolls-Royce, Westinghouse, BWXT and GE Vernova are building for defence-linked programs are largely the same product lines being sold to civilian utilities, industrial sites and, increasingly, energy-security-conscious data-center operators seeking firm, carbon-free power. Storage: lithium-ion cell chemistries and fuel-cell architectures developed for military portability (ASPİLSAN’s work is a clear case) feed into the same manufacturing base used for grid-scale storage, backup power and off-grid civilian applications. Marine construction: the specialised vessels and welding capacity shipbuilders like Fincantieri maintain for naval contracts are directly reused for offshore wind installation and cable-laying work, since the underlying skills — heavy steel fabrication, marine engineering, complex systems integration — transfer with little modification.

Frequently Asked Questions

Are these companies primarily defence contractors or energy companies?

It varies. Rolls-Royce and BWXT built their nuclear expertise through decades of naval reactor work and are now extending it commercially. GE Vernova and Honeywell run energy businesses that are corporately distinct from their aerospace-defence operations, even where a sibling division still supplies the military. Westinghouse and General Atomics both sell to defence programs (Janus) while also operating established civilian nuclear businesses.

Is this investment government-funded or private capital?

Both, and the mix varies by project. Rolls-Royce SMR’s UK program is backed by £2.6 billion in government funding; the U.S. Army’s Janus program pays vendors on a milestone basis from a federal budget of up to $2.2 billion; BWXT’s Wyoming fuel facility drew a state government commitment; GE Vernova’s Swedish reactor project and Texas gas-plus-nuclear plant are structured with private partners (Samsung C&T, DS Investment Partners, Blue Energy).

What is ASPİLSAN Enerji?

ASPİLSAN Enerji is a Turkish battery and power-electronics manufacturer supplying lithium-ion cells, battery packs and fuel cells for the country’s military platforms, while also developing the same cell and fuel-cell technology for civilian energy-storage use.

Do these companies build nuclear power plants directly, or just components?

Both. Rolls-Royce SMR and GE Vernova (through its Hitachi joint venture technology) design and deliver full reactor systems. BWXT and General Atomics have historically supplied reactor components and fuel-related manufacturing, though General Atomics was selected as a full vendor under the Army’s Janus microreactor program. Westinghouse supplies reactor designs, fuel and services across both roles.

Sources

• Rolls-Royce SMR — press releases on the UK Government contract and the ČEZ Group Early Works Contract, 2026 — rolls-royce-smr.com
• GE Vernova News — Studsvik/ReFirm nuclear agreement and Q1 2026 electrification order data — gevernova.com
• Honeywell — “Honeywell Aerospace, Department of War Sign Groundbreaking Agreement,” March 2026 — honeywell.com
• U.S. Army — “Army Reaches Agreement with Private Industry for Nuclear Micro-Reactors,” August 2026 — army.mil
• Fincantieri — “The Board of Directors approves the 2026-2030 Business Plan” — fincantieri.com
• ASPİLSAN Enerji — company announcements on the A35 cell and CES 2026 participation — aspilsan.com

Latest Developments

• November 2026: The US Air Force and Army have now named specific bases and contractors for on-site microreactors under the ANPI and Janus programs — see Can Microreactors Power Military Bases? for the full base-by-base breakdown.
• October 2026: For a deep dive into Rolls-Royce SMR’s ownership, UK government contract and export strategy, see Why Is Rolls-Royce Building SMRs?
• September 2026: The U.S. Army awarded conditional Enhanced Use Leases to Ameresco, the Indelible-Bloom Energy partnership and Frontier Power USA to build nuclear, fuel cell and battery power at six Army installations — read the full story: US Army Picks Nuclear, Fuel Cell Power for Six Bases.
• September 2026: Škoda JS, part of CEZ Group (a 20% shareholder in Rolls-Royce SMR), was named sole supplier of control rod drive mechanisms for Rolls-Royce SMR’s 470 MWe reactor design — read the full story: Škoda JS Named Sole Supplier of Control Rod Drives for Rolls-Royce SMR.
• October 2026: For how much power these installations actually use, and how new leases fit into total consumption, see How Much Energy Do Military Bases Consume?

Illustrative image. Photo: MC2 Bryan Blair, Public domain, via Wikimedia Commons — source