Conversion From L to H Gas: What Does This Mean for My Heat Treatment Operation?

By Matthias Rink – Ipsen International GmbH

You may be affected by the requirement to convert from L (low-calorific) to H (high-calorific) gas by 2030. You can find out if you are affected on your gas bill or from your gas supplier. If you are affected, your gas network operator will contact you, identify your appliances and discuss how to organise the conversion. As a commercial and industrial customer, you can also seek advice from the equipment manufacturer or from maintenance companies certified in accordance with DVGW G-676.

What is the difference between L gas and H gas?

Germany buys gas from different sources. Gas from Norway and Russia is mostly H-gas with a very high content of methane and other hydrocarbons. Gas from the Netherlands is mostly L-gas with lower hydrocarbon contents, as it contains about 10 % nitrogen. This means that after the conversion you will need less gas for the same calorific value, so the flow rates for gas and air need to be adjusted.

Why does the conversion have to be made?

L-gas is no longer available in the short to medium term, as extraction from the Groningen natural gas field is expected to end in mid-2022. Originally, prolonged use of the natural gas field was planned, but a massive increase in earthquakes (seismic disturbances) has prompted the Netherlands to end extraction earlier. The Netherlands will meet its supply obligations, and will therefore supply “pseudo L-gas” during the transition period. “pseudo L-gas” is produced by adding nitrogen to H-gas in conversion plants.

What does this mean for your heat treatment plant?

As described above, your gas network operator will contact you to identify your gas consumers and discuss the changeover. The following gas consumers in heat treatment plants must be converted to the new gas quality:

  • Heating burners (e.g. Ipsen Recon burners)
  • Endogas generators
  • “Endexo” retorts
  • Safety devices “flame curtains, pilot and ring burners

Similar to routine maintenance work, the burners and generators are adjusted to the appropriate gas-air mixture and the exhaust gas or process gas is checked. Furthermore, the pilot and ring burners as well as flame curtains must be adjusted to the correct size.

Whether and which components have to be replaced, or whether the conversion can only be achieved by other adjustment values has to be checked in each individual case and also depends on the maintenance status of the system.

Cost allocation and reimbursement

The natural gas conversion involves an amount of work that is not inconsiderable and therefore associated high costs. However, the legislator has ensured that gas customers affected by the conversion with adaptable gas appliances will be relieved of the directly incurred costs.

The costs associated with the conversion of adaptable gas appliances from L to H-gas are initially borne by the respective network operator in accordance with § 19a of the German Energy Resources Policy Act (EnWG). In a second step, they will be apportioned across all gas customers nationwide. For more information, please feel free to contact us at