We’ve updated our NES(GHG:IPH) Threshold Calculator
15 July 2024
We have updated our NES: GHG (Industry) Threshold Calculator to address:
Updated emission factors published by MfE (2024);* and
Differences between capacity and real life operation (boiler load factor).
This second item was in response to a real life example (see case study below) that gave rise to an apparent disparity between potential and actual emissions.
Case Study: The Little Boiler that Should
Greater Wellington contacted us about a 1.1 MW boiler running for 2,000 hours per year. Our handy GHG threshold calculator tool estimated that the site would emit 598 tpy of CO2. This exceeds the low emissions threshold (500 tpy) and means the site would need a consent. But the site said they only emitted just over 200 kg of CO2 per year.
The site was correct. This is because in practice, they only used 70 tpy of LPG. Turns out the boiler was not being run at 100% maximum continuous rating (MCR). Rather it was modulating to heat water, with an operating load factor of only 38%. Therefore whilst the boiler had the capacity to exceed the low emissions threshold, in practice the boiler does not emit this much.
This means the boiler does not need consent under the NES(GHG:IPH). This site would exceed the threshold if they use more than 168 tonnes of LPG per year.
The take away from the case study is to use actual fuel use for calculating annual GHG emissions in preference to estimates based on boiler capacity and assumed operation.
We have added a Fuel Use page to the front of our calculator to do this.
Click here to download the updated free NES: GHG (Industry) threshold calculator v2.
Whilst we are making this tool available free of charge, we would appreciate acknowledgement to Emission Impossible Ltd and Steve Goldthorpe as the app developers.
Need help? Contact us here.
*Please note, the MfE Guide appears to have an error in the emission factor in Table A2 for LPG (63.27 t CO2/TJ). We have relied instead on the 2008 NZ Energy Information Handbook assuming a 60:40 propane butane mix (60.4 t CO2/TJ).