Hydrogen-Assist for Solar Induction Melting: When Green H2 Makes Sense in a Foundry
Green hydrogen is the other piece of the decarbonization puzzle for foundries. Solar PV provides the daytime electricity for the induction furnace. Green hydrogen - produced by electrolysis powered by solar - provides a high-energy fuel for the times when solar is not available and the battery is empty. The combination of solar PV, battery storage, and green hydrogen gives a foundry a real path to zero-carbon operation. But the hydrogen only makes sense under specific conditions. Here is how the analysis actually works.
Start with what hydrogen does for a foundry.
Hydrogen is a high-energy fuel. When burned with oxygen, hydrogen releases 142 MJ per kg (or 39.4 kWh per kg) of energy - about 2.5 times the energy content of natural gas per unit mass. The combustion product is water, not CO2. So hydrogen is a zero-carbon fuel at the point of use.
In a foundry, hydrogen can be used in three main ways:
Way 1: hydrogen combustion in a boiler or process heater. The boiler produces steam or hot water for the foundry's heating needs. The hydrogen replaces natural gas. The burner is modified to handle hydrogen (different flame speed, different flame temperature, different air-fuel ratio).
Way 2: hydrogen combustion in a holding furnace. Some foundries use gas-fired holding furnaces to keep the melt at temperature between batches. Hydrogen can replace natural gas in these furnaces, with similar burner modifications.
Way 3: hydrogen fuel cell for electricity. A hydrogen fuel cell (PEM or solid oxide) converts hydrogen to electricity with 50 to 60 percent efficiency. The electricity goes to the induction furnace. The fuel cell replaces both the natural gas and, to some extent, the battery storage.
Each of these has different economics, different technology readiness, and different application fit.
The hydrogen has to be made from somewhere.
Green hydrogen is produced by electrolysis of water using renewable electricity. The electrolyzer splits water into hydrogen and oxygen using an electric current. The hydrogen is compressed, stored, and used as needed.
The main electrolyzer technologies are:
- PEM (Proton Exchange Membrane) - fast response, high current density, but uses expensive platinum-group catalysts
- Alkaline - mature technology, lower cost, but slower response and lower current density
- Solid Oxide (SOEC) - high efficiency, but high temperature (700 to 800 degrees C) and slow startup
For solar applications, PEM is favored because of its fast response - the electrolyzer can ramp up and down quickly to match the variable solar input. Alkaline is also used, particularly for larger installations where the lower cost matters more than the response time.
The cost of green hydrogen depends on the electricity cost and the electrolyzer utilization.
The LCOH (levelized cost of hydrogen) calculation is roughly:
LCOH = (Capex of electrolyzer + Opex) / (Electricity consumed x Electrolyzer efficiency)
For a 10 MW PEM electrolyzer running at 50 percent utilization (a typical solar-only input) and using electricity at $30 per MWh (a typical solar PPA price), the LCOH is in the range of $4 to $7 per kg of hydrogen.
At $5 per kg of hydrogen, the energy cost is $5 / 39.4 kWh = $0.127 per kWh of hydrogen energy. This is the cost of the hydrogen at the electrolyzer outlet, before any compression, storage, or transportation.
The cost of the hydrogen at the burner tip includes the compression (to 200 to 800 bar for storage), the storage (in tanks or underground caverns), and the transportation (if the electrolyzer is not at the foundry). These add $1 to $3 per kg to the cost. So the delivered cost of green hydrogen at the foundry is $5 to $10 per kg in 2026.
The economic comparison with natural gas.
Natural gas at $0.30 per cubic meter (a typical Asian price) has an energy cost of $0.30 / 9.7 = $0.031 per kWh. Green hydrogen at $6 per kg has an energy cost of $6 / 39.4 = $0.152 per kWh. So green hydrogen is roughly 5 times more expensive per unit of energy than natural gas in 2026.
The comparison changes in regions with higher gas prices (Europe, Japan). Natural gas at $1.00 per cubic meter has an energy cost of $0.103 per kWh. Green hydrogen at $6 per kg is still more expensive, but the gap is narrower (1.5x).
The comparison also changes as electrolyzer costs drop. Industry projections suggest LCOH of $2 to $3 per kg by 2030 in regions with good solar resources. At $2.50 per kg, the energy cost of green hydrogen is $0.063 per kWh, which is approaching parity with natural gas in many regions.
The carbon cost changes the calculation.
In a region with a carbon price of $80 per ton of CO2, the cost of natural gas is increased by roughly 0.18 kg CO2 per kWh x $80/1000 = $0.014 per kWh. So the effective cost of natural gas is $0.031 + $0.014 = $0.045 per kWh. Green hydrogen at $0.152 per kWh is still 3x more expensive, but the gap is closing.
At a carbon price of $200 per ton (a possible future level), the cost of natural gas rises to $0.031 + 0.18 x 0.2 = $0.067 per kWh. Green hydrogen at $0.063 per kWh is now cheaper than natural gas in carbon terms.
The break-even carbon price for green hydrogen at $5 per kg is roughly $400 per ton of CO2. That is above most current carbon prices but is in the range that some studies project for 2030 to 2035.
The application fit for hydrogen in a foundry.
Not all foundry applications are equally suited to hydrogen. The high-temperature, continuous processes (melting, holding) are good fits. The intermittent, low-temperature processes (space heating, domestic hot water) are less economic because the capital cost of the hydrogen system is harder to amortize.
The best application is the holding furnace. A gas-fired holding furnace running 24/7 can use a large amount of hydrogen. The burner modification is straightforward. The hydrogen supply can be from on-site storage or a pipeline. The economics work if the gas price is high or the carbon price is meaningful.
The second best application is the steam boiler. A foundry steam boiler running 12 to 24 hours per day can use hydrogen as a supplementary or replacement fuel. The boiler burner is modified to handle a hydrogen-natural gas blend or pure hydrogen.
The third application is the fuel cell for peak power. A hydrogen fuel cell can supply the peak demand of the induction furnace when the solar is not enough and the BESS is depleted. The fuel cell is sized to the peak (typically 0.5 to 2 MW), and the hydrogen storage is sized to the runtime needed (typically 4 to 12 hours of peak demand).
The combination is the key.
The most economic application of green hydrogen in a foundry is as part of a hybrid system:
- Solar PV for the bulk daytime energy
- BESS for short-term storage and peak shaving
- Green hydrogen for long-term storage and high-temperature heat
- Backup grid or generator for emergency
The hydrogen handles the days when the solar is not enough and the BESS is empty (multi-day cloudy weather, or extended winter low-solar periods). The hydrogen is produced when the solar is abundant (summer, sunny days) and stored for use when it is needed.
The economics depend on the local conditions. In a sunny region with high gas prices, the system is already economic. In a less sunny region with low gas prices, the system is not yet economic. The trend is toward earlier break-even as electrolyzer costs drop and carbon prices rise.
Author: MONTE INTELLIGENCE hydrogen energy team. For hydrogen system feasibility and cost analysis, contact helenxu@cnlymonte.com.
