Nitrous Oxide emissions associated with 100% hydrogen boilers: research

Introduction

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.