BlueMilk research tackles carbon reduction in Germany

In Germany’s BlueMilk joint project, scientists from the Technical University of Ingolstadt (THI) have, together with dairies and other companies, examined how dairies can actively help shape the energy transition and reduce their greenhouse gas emissions.

The BlueMilk research project is funded by the Federal Ministry of Food and Agriculture. The German government has set itself the goal of sourcing 80% of electricity consumption from renewable energies by 2030 in order to achieve the overriding goal of net greenhouse gas neutrality by 2045. This requires an enormous expansion of photovoltaic and wind power plants, which, also means volatile power generation and demands flexibility from consumers and controllable power generators.

Dairy companies could meet this with flexible energy concepts, the researchers say. Professor Uwe Holzhammer thinks that flexibility in detail and in interaction will be necessary in the future in order to be able to react to the conditionally plannable power generation from wind and photovoltaics.

“This is the only way, which the future renewable electricity volumes can be used cost-efficiently. Flexibility is not a burden. It offers companies the opportunity to stabilise energy costs,” Holzhammer says.

The approach is to use fluctuations in electricity exchange prices to the company’s benefit. The project came to the conclusion that this approach saves emissions at the same time. If the share of renewable energy in the public power grid is high, emissions are also low. Clean electricity is therefore also cheap electricity.

Volker Selleneit, research associate at the THI, has examined different energy supply concepts for dairies, which can provide this flexibility with combined heat and power plants (CHP) and the approach of sector coupling (heat is generated from electricity).

Both the energy supply costs for dairies and operational emissions are to be reduced in this way. To do this, it is necessary to plan the use of energy conversion systems intelligently and strategically with a view to 2030, he notes. The optimisation was simulated in models, taking into account fluctuating electricity exchange prices, and compared with the existing concept of self-supply of electricity by a combined heat and power plant. This is a design that has been common in recent years.

The results for the years 2020 to 2022 showed large differences. In 2020, the energy supply costs for flexible concepts were significantly higher than the previous concept of self-supply of CHP power. For 2021 and 2022, however, the cost situation was turning, and flexible concepts were a more cost-resilient alternative.

The THI team of scientists expects a development towards significantly more volatility in the electricity supply and thus in the electricity price in the future. At the same time, with increasing flexibility of the processes, business risks can be reduced in the years with extreme prices and price fluctuations such as 2022.

In the studies, it was particularly positive that the company’s greenhouse gas emissions can be reduced in any case with flexible concepts. In connection with adapted heat utilisation concepts, which Selleneit also considers necessary, further increases in efficiency and reductions in greenhouse gases are possible.

Martin Stöckl, also a research associate at THI, dealt with the special flexibility option of cooling systems in dairies. “If the proportion of renewable energy in the public power grid is high, the temperature in the cold store is lowered. Conversely, the cooling capacity is reduced, when the renewable energy share is low. The products themselves store the necessary cold and only move within a predefined temperature range in order to ensure continued high quality,” Stöckl notes.

This means that there are normally around 5ºC in the cold store. But if the sun shines during the day, it can be cooled more. The cold stored in the products can then be used at night and the system switched off.

If it is possible to further reduce the temperatures of the products before transport using renewable electricity than is currently the case, costs, resource consumption and emissions can also be reduced in the logistics chain. The scientists see great potential here for reducing carbon emissions and at the same time, improving the economic competitiveness of the dairies.

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