SUMMARY: In-house acidification as an instrument for implementing Danish climate policy – a technical analysis

By Henning Lygnsø Foged, Organe Institute ApS. Read the full report in Danish on

In 2020, the Climate Partnership for the Food and Agriculture Sector published a report in which in-house acidification is proposed as one of the measures the sector recommends for achieving the government’s goal of a 70% reduction of CO2e emissions until 2030. Specifically, the proposal is to acidify an additional 32 % and 38 % of slurries from sows and piglets and a further 12 % of the cattle slurry.

JH Agro A/S, who produce in-house acidification systems, has asked Organe Institute for a second opinion regarding the effects of the outlined use of in-house acidification.

The assessment is that the proposed use of in-house acidification will have a total positive value of DKK 1,401 (€ 188) per tonne of CO2e, covering a positive value for the society of DKK 1,848 (€ 248) per tonne of CO2e and a negative value for the agricultural sector of DKK 447 (€ 60) per tonne of CO2e. For the agricultural sector, the net expenditure corresponds to an expenditure per tonne of slurry of DKK 13.74 (€ 1.84).

The climate effect includes a total net reduction of almost 186,000 tonnes of CO2e annually. With an estimated average value until 2030 of DKK 469 (app. € 63) per tonne of CO2e, the climate effect has a value for the society of DKK 87 million (M€ 11.7) per year. Societal benefits of in-house acidification also include cleaner air and cleaner water. Ammonia emissions will be reduced by 4.0 Kt, and the aquatic environment saved 2,257 tonnes of nitrogen. These things together have a societal value of 225 million DKK (M€ 30.2) per year, the majority of which relates to savings in the health care sector, including sick days and hospitalizations.

For the agricultural sector, the proposed use of in-house acidification means additional costs for the purchase of sulfuric acid of DKK 45 million (M€ 6) annually, and extra fuel consumption of DKK 4.1 million (M€ 0.55) annually. On the other hand, the agricultural sector saves DKK 30 + 10 million (M€ 4 + 1.4) annually on purchase of nitrogen, respectively sulfur in the form of mineral fertilisers, DKK 1.1 million (M€ 0.15) for the purchase of starter fertiliser for maize, DKK 4.6 million (M€ 0.62) regarding the establishment of floating layers on slurry tanks, and DKK 4 million (M€ 0.54) for injection of slurry. Together with the financing costs, the annual net expenditure for the agricultural sector is almost DKK 76 million (M€ 10.2). All the mentioned figures excludes any potential subsidies.

This provides an overall overview of the significant effects of using in-house acidification to the extent proposed by the Climate Partnership for Food and Agriculture, and at the same time provides a clear basis for a possible political decision on a redistribution of the capitalised value of the effects between the agricultural sector and the society.

Apart from the report itself, an EXCEL file with the calculations behind the results that are presented in the report is made available. In the EXCEL file, each calulation has a clear literature reference to the used assumptions. In this way, the calculations and thus the way the results are produced, are completely transparent. The EXCEL model is unlocked, and may be used for estimation of other scenarios.

Find the Excel file on