Nitrous Oxide emissions associated with 100% hydrogen boilers: research

Research to measure the gas composition of flue gas from hydrogen boilers under normal, real world operating conditions, with a view to establishing what, if any, greenhouse gases are emitted during combustion.


TÜV SÜD National Engineering Laboratory was commissioned to undertake a series of tests at suitable hydrogen boilers in domestic settings. The primary objective was to determine N2O emissions, but additional measurements of oxygen and moisture were also required to standardise the data in accordance with the appropriate Standard. Measurements of oxides of nitrogen (NO/NO2, expressed as NOx) were also carried out.

Measurements were carried out at a fully functional domestic facility. This facility comprises two homes which are fitted with purpose-built hydrogen gas appliances including cookers and hobs, fires and boilers and a hydrogen meter. The appliances are very similar to today’s natural gas appliances and operate in the same way.

The measurements were performed under a variety of conditions intended to reflect real-life domestic operation and the results expressed as an estimated annual emission and as carbon dioxide equivalents.

Only one boiler was available and tested over a range of 6.4 kWh to 29.0 kWh. We were unable to arrange access to a further two boilers at an alternative location due to limited availability and time constraints.



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