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.


Summary of Results

The N2O results are presented in Table 1 below. The full set of test data is shown in Appendix 1 along with trend data obtained during the test period.

The measured N2O emission concentrations in the exhaust flue were at the detection limits for the low and modulation firing modes. The high fire mode resulted in measured values above the detection limit and these peaks can be seen in the real-time trend data in Appendix 1.

The increase in N2O emission concentrations during the high fire period are consistent with the emissions data from the NOx and oxygen measurements (increased NOx, reduced oxygen).

Table 1. - Summary of Results ( N2O)
Time Operational Mode Average N2O Result
N2O (mg/kWh) CO2e kg/kWh
10:30 – 10:51 Modulation 0.00 0.00000
11:07 – 11:31 Low Fire 0.00 0.00000
11:36 – 12:05 Low Fire 0.00 0.00000
12:22 – 12:32 Low Fire 0.00 0.00000
12:42 – 12:55 High Fire 0.50 0.00013
13:04 – 13:22 High Fire 0.74 0.00020

Table 2. - Estimated Annual Emission (N2O)

Weighted average: 0.272 N2O (mg/kWh)

Weighted CO2 equivalent: 0.00007 CO2e kg/kWh

Contact

Email: 2024heatstandard@gov.scot

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