Biogas plants can dramatically cut carbon emissions of dairy farms

In Europe, large scale dairy farms are turning to on-site biogas plants to meet energy needs while cutting their carbon emissions
German biogas specialist Weltec Biopower is building a biomethane plant for the large-scale Spanish dairy cattle farm Torre Santamaría

German biogas specialist Weltec Biopower is building a new biomethane plant for the Spanish dairy cattle farm Torre Santamaría.

The Catalan family business built its first 250kW biogas plant back in 2011, and since that time it has been able to cover its entire energy demand from its own residues. The farm in Vallfogona de Balaguer was the first milk producer in Spain to use cow effluent for the production of energy.

The investment in the new biomethane plant amounts to more than $6 million and a quarter of this sum will be spent on modernising the existing infrastructure and biogas plant.

One of the reasons why Catalonia‘s second-largest dairy producer is able to allocate a budget of this magnitude is that excess biomethane from the plant has already been on-sold to an energy service provider that will market it as a climate-friendly fuel.

“We view this plant as an environmental investment, as it allows us to cut our own greenhouse emissions almost to zero and generate additional income from biomethane,” said Juan Bautista Pons Torrades, Managing Director and owner of Torre Santamaría.

The farm produces some 22 million litres of milk per year and is a leading supplier of the A2 milk variant.

“To produce this amount of milk, we keep 2,300 dairy cows and 2,100 calves on an operating area of 14.2 hectares,” said Torrades.

Torre Santamaría
Intensive farming practices at the Torre Santamaría operation produce some 60,000 tonnes of effluent each year that provides the raw material for biogas production

Every year, some 60,000 tonnes of input substances accumulate for use in the biogas production.

Cattle manure accounts for about 90 percent of the substrates. Bedding consisting of ground straw as well as silage leftovers are also fed into the digester.

Currently, Weltec is setting up two additional stainless-steel digesters for the digestion of all residues on the farm. Each of the digesters has a height of 6.3m, a diameter of 26.87m and a capacity of 3,573 m³.

“After processing the biogas generated in the digesters, Torre Santamaría feeds 300 standard m³/h of biomethane into the natural gas grid,” reported Mark Kornweibel, the Spanish sales partner of Weltec Biopower.

According to Kornweibel, the existing 250kW co-generation power plant will continue to be operated despite the transition to renewable natural gas (RNG) production.

The farm is thus able to cover its own demand for power, heat and hot water.

After the new plant is finished in summer 2021, Torre Santamaría will continue to satisfy its demand for energy from its own raw material.

Moreover, the plant operation enables the Catalans to shoulder their corporate social responsibility and maintain a healthy balance between environment, social concerns, economic factors, and security of food and energy supply.