Getting more heat from every cubic metre of gas: oxyhydrogen in glasshouse boilers

For many glasshouse growers, gas is now one of the biggest costs after labour. Heating plants run for months on end, often 24 hours a day, and every percentage point of fuel efficiency shows up directly in the margin.

I've spent four decades working with oxyhydrogen, the hydrogen and oxygen mixture produced by splitting water. Its most practical use today isn't replacing fuel; it's helping the fuel you already burn to burn better.

How it works

An oxyhydrogen generator uses electricity to split water into hydrogen and oxygen. The gas is made on demand, with no storage tanks, and fed in small amounts into the burner or its combustion air.

Three effects matter:

• Faster flame: hydrogen burns much faster than natural gas, which helps the main fuel burn more completely.
• Built-in oxygen: the mixture carries its own oxygen, which can let the burner run with less excess air. Less excess air means less heat lost up the flue.
• A more even flame: fewer cool spots where fuel burns incompletely.

It's important to be clear about scale. The oxyhydrogen is a small fraction of the gas flow, typically around 2% of the main fuel, and on its own it supplies very little heat. Any saving comes from better combustion of the main fuel, not from the hydrogen replacing it. Anyone who tells you otherwise is overselling.

What results look like

On a ten-plant biomass-fired steam fleet in India, measurements taken by our engineers together with the client's plant teams showed an average 13% improvement in steam produced per unit of fuel. That was on biomass boilers, and results on natural gas will differ. For gas-fired glasshouse boilers, a realistic planning range is more modest, and it should be proven on your own plant rather than assumed.

That's why I recommend every installation starts with measurement:

• Baseline first: log gas use, steam or hot-water output, flue temperature and oxygen before installation.
• Then compare, under similar conditions, with the generator running.
• Decide on the numbers. If the saving doesn't justify the electricity and the equipment, the data will show it.

What a typical installation involves

Our Glasshouse Boiler Oxyhydrogen Generator is sized for small-to-medium boilers. It produces 6,000 L/h from 20 kW, the most efficient in our range at 300 L/h per kW. One unit suits up to about 4 tonnes per hour of steam equivalent, and two in parallel cover up to about 8. It sits beside the existing plant, connects to the burner through a non-return valve and flame arrestor, only runs while the burner fires, and doesn't require changes to the burner or fuel train. Your local contractor completes the installation to local combustion and gas regulations, with our engineers guiding commissioning remotely.

The broader point

Glasshouses sit where energy and agriculture meet: heat, CO2 and water all have to be managed together. Combustion enhancement is one practical, measurable lever on the energy side. Like any engineering change, it should be judged on data from your own site.

If you operate a glasshouse, nursery or industrial boiler house and want to explore a measured trial, I'm happy to talk it through.