Level 1 - Absolute Beginner

A company from Finland made a special engine. The engine uses only hydrogen as fuel. It produces electricity.

The engine was tested in Spain. The electricity it made went to Spain's national power grid. This was a very important test for clean energy.

Hydrogen is a clean fuel. When it burns, it produces only water. This is much better for the environment than burning coal or oil.

engine

a machine that uses fuel to produce power or motion

hydrogen

a very light, colorless gas that can be burned as a clean fuel

electricity

a form of energy used to power lights, machines, and electronic devices

fuel

a substance that is burned to produce heat or power

grid

a network of wires and cables that carries electricity from power stations to homes and businesses

clean energy

energy that is produced without creating harmful pollution or greenhouse gases

demonstration

a practical display or test to show that something works

environment

the natural world around us, including air, water, land, and living things

Level 2 - Elementary

On June 11, 2026, Finnish energy company Wartsila ran the world's first large-scale 100% hydrogen engine and fed its power directly to Spain's national electricity grid. The test was held at the company's Bermeo laboratory in northern Spain, and energy experts from around the world were invited to watch.

The engine, called the Wartsila 31H2, can produce up to 9.8 megawatts of power - roughly the same as 13,000 horsepower. It is a large piston engine about the size of a bus, designed to show that hydrogen can power a national electricity network under real conditions.

Hydrogen is seen as a promising answer to one of renewable energy's biggest problems: what to do when there is no wind and no sunshine. Hydrogen can be produced from water using electricity from wind farms and solar panels, then stored and burned later when needed.

Experts say the technology still faces challenges, especially around building enough hydrogen storage and transport systems. But this successful test shows that hydrogen engines can work at a large scale, opening a new path toward clean backup power for countries around the world.

piston engine

an engine that converts the back-and-forth movement of pistons into rotating power

megawatt

a unit of power equal to one million watts, used to measure large amounts of electricity

milestone

an important event or achievement that marks a significant stage in a process

renewable energy

energy from sources that are naturally replenished, such as sunlight, wind, and water

storage

the process of keeping a substance or resource in a secure place for future use

combustion

the chemical process of burning a fuel to release energy

infrastructure

the basic systems and facilities a country needs to function, such as roads, grids, and pipelines

backup power

electricity generated to replace the main supply when it is unavailable or insufficient

Level 3 - Intermediate

Wartsila, the Finnish energy and marine technology company, achieved a globally recognized engineering milestone on June 11, 2026, when it successfully powered part of Spain's national grid using a Wartsila 31H2 engine running on 100% pure hydrogen at its Bermeo research facility in the Basque Country.

The 31H2 is a modified version of Wartsila's 31-platform engine, already regarded as one of the world's most efficient multi-fuel four-stroke internal combustion engines. Adapted to combust pure hydrogen rather than natural gas, it produces up to 9.8 megawatts of electrical output - roughly 13,000 horsepower - in a footprint comparable to a transit bus. Crucially, the test validated the engine's ability to operate stably under real grid conditions rather than in controlled laboratory isolation.

The demonstration addresses one of the central engineering challenges in the energy transition: intermittency. Solar and wind installations generate power only when conditions allow, but electricity demand is constant. Hydrogen offers a form of long-duration energy storage - excess renewable electricity can be used to split water into hydrogen and oxygen via electrolysis, and the stored hydrogen can then be burned in engines like the 31H2 to generate dispatchable power on demand.

Commercializing this pathway at grid scale faces significant hurdles. Pure hydrogen has a lower energy density per unit volume than natural gas, requiring larger storage tanks. The cost of green hydrogen produced using renewable electricity remains two to three times higher than fossil fuel alternatives. Nevertheless, Wartsila has announced plans to bring the 31H2 to market in 2026, targeting markets with high renewable energy penetration and limited domestic gas reserves.

intermittency

the tendency of solar and wind power to stop and start depending on weather conditions

dispatchable power

electricity that can be switched on or off immediately on demand to meet changing grid needs

electrolysis

a process that uses electricity to split water into hydrogen and oxygen gases

energy transition

the global shift away from fossil fuels toward cleaner, renewable energy sources

penetration

the degree to which a technology or energy source has spread into a market or energy system

four-stroke engine

an internal combustion engine that completes a power cycle in four distinct piston movements

energy density

the amount of energy stored in a given volume or mass of a fuel

green hydrogen

hydrogen produced using electricity from renewable energy sources such as wind and solar

Level 4 - Advanced

Wartsila's June 11, 2026, demonstration of the 31H2 piston engine at its Bermeo research facility in the Basque Country - feeding up to 9.8 megawatts of electricity generated from 100% hydrogen combustion into Spain's national grid - represents the most operationally credible proof-of-concept yet for hydrogen as a dispatchable balancing resource in a mature renewable energy system.

The significance lies not in the existence of hydrogen combustion technology but in its execution under live grid conditions at megawatt-class scale, with the attendant synchronization demands, frequency regulation requirements, and ramping behavior that commercial grid operators actually require. The 31H2 is a derivative of Wartsila's 31 platform, an engine family already operating commercially on natural gas across 60 countries; the hydrogen-specific modifications center on injection geometry, pre-chamber design, and combustion management algorithms designed to suppress NOx emissions, which hydrogen combustion paradoxically risks increasing relative to gas.

The structural case for hydrogen-fueled dispatchable generation rests on the convergence of two trends: the saturation of VRE-dominated grids - characterized by increasingly negative spot prices during peak solar hours and severe price spikes during Dunkelflaute periods of simultaneous low-wind, low-solar output - and the growing cost-competitiveness of electrolytic green hydrogen, whose levelized cost has fallen from approximately $6 per kilogram in 2020 toward a projected $1.50 to $2.50 per kilogram by 2030.

Commercial viability remains conditioned on policy support, carbon pricing, and the build-out of hydrogen transport and storage infrastructure - challenges particularly acute in markets like Spain, where natural gas import terminals are well-capitalized but purpose-built hydrogen pipelines essentially do not exist. Wartsila's positioning of the 31H2 as a gas-to-hydrogen transitional technology deployable in existing gas engine power stations addresses the capital expenditure objection but does not dissolve the hydrogen availability bottleneck that has frustrated earlier decarbonization timelines.

Dunkelflaute

a German term for dark doldrums, meaning periods of simultaneously low wind and solar energy output

NOx emissions

nitrogen oxide gases released during high-temperature combustion, contributing to air pollution and smog

levelized cost

the average total cost of producing one unit of energy over a technology's entire operational lifetime

VRE-dominated

describing an electricity system with a high share of variable renewable energy such as solar and wind

synchronization

the alignment of a generator's electrical frequency and phase with those of the wider power grid

ramping

the ability of a power plant to increase or decrease its electricity output quickly in response to demand