Bottling

the Sun

Compact fusion power plants that put clean, always-on electricity on the grid. First plant online in 2034.

Plasma12,000,000 °CPower out ÷ in0.00×Shot#4,112 · Standby

Hold to fire a shot

Why fusion, why now

The hydrogen in a litre of seawaterholds as much energy as 300 litresof petrol. We build the machinethat gets it out.

How the machine works→Our story→

400 MW

Net electricity from one plant, day and night

320k

Homes one plant supplies, about a city the size of Cardiff

0 t

CO₂ at the stack. No long-lived waste, no meltdown physics

2034

First power to the grid from Halvard One

Halvard

\ ˈhal-vərd \

noun. A compact fusion power plant: 400 megawatts of steady, carbon-free electricity from two isotopes of hydrogen, on a site the size of two football pitches.

Halvard One · how it works

Anatomy of a shot

Seven systems, one job: keep a star-hot plasma in the middle of the room for long enough to make more energy than it takes. Scroll to take the machine apart.

01 · 18 T peak field

Central solenoid

Six stacked coils drive the plasma current, like the primary winding of a transformer.

02 · 1 kHz control loop

Shaping coils

Four rings squeeze and steer the plasma into its D shape, correcting it a thousand times a second.

03 · 12 T on axis

Toroidal field coils

Sixteen superconducting D-coils wrap the chamber in a magnetic bottle, cooled to −253 °C.

04 · 150,000,000 °C

The plasma

Hydrogen fuel heated ten times hotter than the Sun's core, held clear of every wall by field alone.

05 · 6,400 tiles

Vacuum vessel

A double steel wall lined with 6,400 tungsten tiles. The lithium blanket behind them breeds new fuel.

06 · 10 MW per m²

Divertor

The exhaust. It strips helium ash from the plasma edge and takes heat like a rocket nozzle.

07 · 1,900 t

Cryostat base

Carries the 1,900-tonne machine and keeps the cold parts cold inside a vacuum jacket.

01020304050607

MachineHalvard OneTypeCompact HTS tokamakNet output400 MWe

How a shot works

Four steps fromseawater to socket.

010.5 g of fuel per hour

Fuel in

Deuterium from seawater and tritium bred inside the machine are frozen into pellets smaller than a grain of rice and fired into the chamber, 20 times a second.

0212 tesla on axis

Magnets on

Sixteen superconducting coils make a field 250,000 times stronger than the Earth's. It holds the plasma in a ring, clear of every wall.

03650 °C blanket outlet

Heat out

Fusing nuclei throw off fast neutrons. They are stopped in a molten-salt blanket around the chamber, which heats up to 650 °C and breeds new fuel.

04400 MW net

Power out

The hot salt boils water, the steam turns a standard turbine, and the grid sees what it always sees: steady, synchronous power.

Halvard One · Aberthaw, Wales

A power stationthat fits on abrownfield site.

We build where coal plants stood. The cooling water, the grid connection and the workforce are already there. Tap a building to see what it does.

Aerial view of an industrial site with mountains behind

01 · Tokamak hall42 m

The machine sits in a 42 m hall under a steel dome, on the footprint of the old coal plant's boiler house.

Where the heat goes

Electricity is halfthe story.

Two thirds of industrial energy is used as heat. Halvard's blanket runs at 650 °C, hot enough to replace gas in most of what factories do, and it can switch between heat and power every hour.

Hot water · 55–65 °C

District heating · 80–120 °C

Hospital sterilisation · 120–140 °C

Data-centre absorption cooling · 90–130 °C

Halvard One · molten-salt blanket · up to 650 °C

Gas turbine exhaust · up to 550 °C

Concentrated solar · up to 400 °C

Water-cooled fission · up to 300 °C

Industrial heat pump · up to 160 °C

0°200°400°600°800°1000°1200°

Sectors

Who buys astar's worth of heat.

All sectors→

01Data centres24/7 power and 90 °C heat for absorption cooling→02SteelHydrogen and heat for direct-reduced iron→03Hydrogen and chemicalsSolid-oxide electrolysis at 700 °C, 30 % less power per kilo→04District heatWaste heat from the turbine warms 90,000 homes→05WaterDesalination that runs on heat instead of gas→06Shipping fuelsGreen ammonia and methanol at port scale→07Utilities and the gridFirm, synchronous power on existing connections→08Cement and glassElectric calcining with fusion-backed power→

How you buy it

You buy megawatt-hours.We keep the star lit.

£0

capital from you

We finance and build

Halvard owns the plant. You sign a 20-year offtake at a fixed price, indexed to inflation, with no capital on your balance sheet.

92 %

availability target

We run it

Our operators, our licence, our spare parts. A 60-person crew per plant, trained at our own simulator in Cardiff.

£48

per MWh, 2034 real

You take power and heat

Electricity at the fence, steam or hot salt by pipe. Switch the mix hour by hour as your process needs.

Milestones

Fifteen years froma drawing to the grid.

Hottest plasma so far

—

2019

Founded in Cardiff

Four engineers from the national lab spin out with a design for a compact, high-field tokamak.

2021

First HTS magnet

A 20-tonne superconducting coil holds 12 tesla for 100 hours straight.

2023

Test machine H-0

First plasma in our half-scale device, 11 million °C for 0.3 seconds.

2025

Record shot

H-0 holds 94 million °C for 8 seconds, a record for a machine its size.

2026

Site consent

Planning consent for Halvard One on the former Aberthaw coal site.

2029

Hall complete

The tokamak hall and turbine refurbishment finish. Coils arrive by sea.

2032

First plasma, H-1

Halvard One lights for the first time.

2034

Power to the grid

400 MW, sold to four offtakers under 20-year contracts.

The team

140 people who havebuilt hard things before.

We are hiring · 23 roles

Dr Maren Holt

Co-founder, CEO

Ran the high-field magnet programme at the national lab for nine years.

Idris Kaan

Co-founder, CTO

Designed the H-0 test machine. Holds the shot record.

Dr Ines Arrieta

Chief Scientist

Plasma physicist. 60 papers on edge stability.

Tom Achebe

VP Construction

Built two combined-cycle plants and a subsea interconnector.

Dr Lena Voss

Head of Blanket and Fuel

Molten-salt chemist, formerly in fission fuel cycles.

Rafael Ondo

Head of Operations

Twenty years in grid control rooms.

Priya Ramanathan

CFO

Financed 3 GW of offshore wind.

Joel Brennan

Head of Safety and Licensing

Former regulator. Wrote the fusion safety guidance.

From the control room

Latest shots and news.

All news

→

Results

4 min

H-0 holds 94 million °C for eight seconds

Our half-scale test machine set a record for its size, and the plasma stayed put for the whole shot.

Company

3 min

Planning consent for Halvard One at Aberthaw

The first commercial fusion plant in Wales will be built on the site of the old coal power station.

Partnerships

5 min

Four offtakers sign for the first 400 MW

A data-centre operator, a steelmaker, a water utility and a regional grid company will take all of Halvard One's output.

Partnerships

Put a staron your grid.

Utilities, industrial buyers and data-centre operators: tell us your load and we will show you a Halvard plant sized to it.

Talk to our team See the plant→