Danish initiatives to lower emissions

The dairy industry and its products are an essential part of the world today, both as a source of nutritious food and as a global industry that generates thousands of jobs while having a meaningful impact on developing countries. However, alongside these benefits comes the issue of its environmental footprint - the emissions of greenhouse gases such as CO2, nitrous oxide, and methane.

In Denmark, industry research and development efforts are addressing this issue from multiple angles, with a broad range of new and continuously evolving initiatives aimed at reducing emissions from cows on the farm as well as from production processes at the dairies.

Driving this work and providing a framework for shared climate objectives are international agreements, like the Paris Climate Agreement, along with Danish national climate legislation. On top of that, the Danish dairy industry and some dairies also implement subsidy models to incentivise farmers to adopt specific climate measures.

The following sections present some of those initiatives, beginning with efforts on the farm, followed by developments in dairy production, and finally, innovations in packaging.

 

The farm, the feed and the cows

On the farm, the majority of emissions are methane, which results from digestion and manure storage, and nitrous oxide, which is released from the use of artificial fertilisers and manure (in slurry form). Nitrous oxide is also released when soil is cultivated (e.g. during ploughing). One of the major focus areas, therefore, is the management of feed and manure to lower these emissions.

 

Barn acidification

The acidification of manure with sulphuric acid reduces ammonia and methane loss within barns and during storage. This process can result in emission reductions of 39% ammonia and 67% methane.

 

Cow suction hoods

Addressing methane emissions from cows has traditionally focused on modifying feed, but in recent years, research has expanded to include technological solutions. Studies are, among other things, examining the effectiveness of cubicle hood systems equipped with suction to capture methane from both the cows and the manure.

 

The hoods are designed with the aim of efficiently reducing methane emissions within barns and slurry tanks. Although still in the development phase, these hoods exemplify ongoing research efforts towards effective emission-reduction solutions.

 

Feed

In addition to an analytical approach aimed at optimising feed efficiency to improve cows’ health, productivity, and cost-effectiveness, many studies have highlighted the benefits of various methane-reducing feed additives. Although most additives are still in the research phase and pending further development, recent studies have explored the following:

• Nitrates: Studies indicate that methane emissions can be reduced by up to 18% through the use of nitrates in feed. However, Danish studies found that nitrates in the feed increase nitrate levels in the milk, raise enteric nitrous oxide emissions, and reduce overall feed intake.
• 3NOP (Bovaer): This recently developed additive shows potential to reduce emissions by up to 39% without side effects for the cows, consumers, or milk quality. It has been approved for use in dairy cows in the EU since 2002.
• Substance X (X2): The promising additive is currently unnamed due to ongoing research and pending patent applications. Although its name is confidential, it is reportedly known and approved in other contexts, though not yet for cow feed.

 

Organic farmers must pursue other alternatives, as the above additives are chemical (with the exception of Substance X, the nature of which is unknown). Instead, researchers are exploring options that include:

• Seaweed: Contains bioactive compounds that can reduce methane production in ruminants’ digestive systems. Some Swedish studies have observed up to 90% reductions; however, concerns persist over the active compound bromoform, which may have harmful health side effects and contribute to ozone depletion, though research continues.
• Fats (Oilseeds, fatty acids): Feed that includes fats (e.g., from seeds, such as rapeseed), is generally accepted to have a significant impact on methane emissions. Added fat in the diet inhibits methane production, with notable effects seen from medium-chain fatty acids (laurin and myristic acid) and poly-unsaturated fatty acids (linoleic, especially linolenic acid).
• Willow & hemp: Rich in condensed tannins and flavonoids, these plants are used to inhibit methane-producing microorganisms. Researchers hope these may achieve reductions of up to 30%.
• Oregano: Contains essential oils, including carvacrol, which has mild antimicrobial properties that may kill some methane-producing bacteria. Though initially effective in lab studies, later research in both the USA and Denmark showed limited success in real-world applications.

 

 

Breeding

Research indicates that some cows are genetically predisposed to emit more methane than others, allowing farmers to selectively breed cows with lower emissions. Through selective breeding, emissions can be reduced by approximately 1% per year. While this may not sound substantial, it is a continuous reduction. There is about a 20% difference in methane emissions between cows with high versus low methane production.

In addition to reducing emissions, selective breeding offers opportunities to enhance cow health. Cow health is crucial for animal welfare, but it is also a priority for farmers, as healthier cows are more productive in terms of milk yield. This ultimately results in a lower overall carbon footprint.

 

Biogas

The organic material in manure naturally transforms into methane, which, when degassed (digested), becomes fuel - reducing methane emissions by approximately 40%.

 

Rewetting of peat soils

Parts of Danish agricultural land are on peat soil, which consists of old wetland (meadows, bogs) that were drained for farming. A downside of this practice is that peat soils are carbon-rich, and when drained and exposed to oxygen, they release significant emissions.

To reduce these emissions, peat soils are being taken out of agricultural use, with plans to restore them to their natural, waterlogged state. Depending on the soil’s carbon content, this effort could result in reductions of between 15 and 40 tonnes of CO2e/ha/year, though these estimates carry a degree of uncertainty.

 

Pyrolysis

Pyrolysis is a technological process that transforms biomass -  such as straw, manure, wood, or sewage sludge - into biochar through oxygen-free gasification. Biochar binds carbon longer than the original biomass, which typically breaks down more quickly and releases greenhouse gases. As biochar contains carbon, the plan is to spread it on agricultural land to create a form of CO2 storage.

The Danish government aims to use this technology to achieve reductions of up to 300,000 tonnes of CO2 by 2030. A pyrolysis fund has been established to incentivise its adoption in agriculture and to support the necessary environmental studies and regulatory framework to understand biochar’s impact and optimal usage.

Several prototype plants are in development in Denmark, and the technology is advancing from demonstration to market maturity across Denmark and Europe.

 

Dairy implementations & energy optimisation

At dairy facilities, the majority of emissions are CO2, and the primary focus is on waste management and optimising resources and energy. Efficiency here is about more than just benefiting the business and the economy - the aim is also to align with climate and sustainability goals. Key strategies include:

• Individual climate goals set by each dairy
• Science-Based Targets
• Transport optimisation, using more environmentally friendly fuels (e.g., biofuel, electricity, hydrogen)
• Transitioning from fossil fuels to renewable energy sources (e.g., biogas, wind, solar cells, etc.)
• Reducing waste in production
• Engaging dairy farmers to achieve reductions on farms

 

In line with the UN Sustainable Development Goals, the responsible use of water is a priority for the dairy industry. Water reuse is an example of resource efficiency, where the water typically goes through a process of reconditioning (e.g., purifying and reducing microbial load). Many farms also reuse water from their cooling systems, used to chill freshly collected milk, and later reusing it for barn cleaning or crop irrigation.

During the milk cooling, dissipated heat can be recovered. What was previously wasted can now be used to heat water for washing, cleaning, or other processing purposes, and thereby reducing the need for additional thermal and electrical energy. With heat pumps, heat from one area of production is recaptured and reused in another, optimising and milking every energy source for all its worth.

On a local level, repurposing heat to prevent waste and circulate ressources has proven particularly successful for an Arla dairy, which redirected surplus heat from cheese production to the district heating plant. Instead of wasting the heat, it was used in the community’s heating system, making the city’s heating 90% fossil-free.