Renewable energy

Biogas is produced through the microbiological decomposition of organic matter in a moist and warm environment under the exclusion of air (anaerobic conditions). In a biological decomposition process (fermentation), the substrates used are mainly converted into methane and carbon dioxide. This process is widespread in nature, occurring in swamps and wetlands or in the digestive tract of ruminants – in our biogas plant, it is purposefully utilized.

The end product is combustible biogas, a mixture consisting primarily of methane (50–75%), carbon dioxide (25–45%), and small amounts of water (2–7%), hydrogen sulfide, oxygen, nitrogen, ammonia, hydrogen, and other trace gases.

The digestate that accumulates after fermentation (consisting of undecomposed biomass and minerals) has excellent fertilizing properties and can be applied to agricultural land. This closes an annual cycle: the fertilizer helps our various crops to grow and ripen, which are then harvested, stored, and fed back into the biogas plant.

From our sustainably produced biogas, we generate electricity each year that covers the average annual consumption of around 3,500 households, as well as additional heat energy that could theoretically supply about 1,500 average households sustainably. (Since heat demand varies depending on the season and part of the heat is also produced during the summer months, this figure should be considered theoretical.)

In 2008, photovoltaic modules were installed on two south-facing hall roofs, providing a combined output of 88.5 kW peak.

For 2021, an extension of the rooftop photovoltaic system is planned, with modules to be installed on the remaining roofs, predominantly with east/west orientation.

Over the coming years, we are working on developing an area of around 8 hectares located directly east of our site. The goal is to generate renewable energy, primarily through a ground-mounted photovoltaic system.

The electricity produced by this PV system could be used at our existing site (biogas plant) for various processes, with the aim of supporting and improving current operations. Another option is to use the energy generated in this project to supply sustainable heat to the municipality. Specifically, we are also considering converting the renewable electricity into hydrogen, making the energy more storable in the long term and usable for sector coupling.

The landscape planning office Längst & Voerkelius from Landshut, which already developed the existing development plan for the “Biogas Plant Ried” special zone and is well known to the municipal committees, has also been commissioned to work on this planned expansion. Längst & Voerkelius therefore prepared the concept presented here.

The municipal council has already unanimously decided to amend the development and land-use plan. The project is now moving forward in the approval process.

What makes this project special is that the ground-mounted PV system will not only be built on our own land but also on leased land from our immediate neighboring families, Wackerl and Zotz. For this purpose, a separate company has already been established with the lessors: EnerGiepark Ried GmbH & Co. KG, based at Ried 3, Markt Indersdorf.

The second unique feature is that the location of this energy park, with its gentle slope and natural enclosure by a forested area, makes it barely visible from the outside.

As part of the planned solar park, we are also specifically considering hydrogen production from a portion of the solar energy generated. For this purpose, an electrolysis plant would be installed, which could look like this:

The advantages of converting to the energy carrier hydrogen lie in its longer and comparatively more cost-effective storability compared to electricity, in the relief it provides to power grids, in its capability for sector coupling, and in the potential to harness synergies in combination with biogas plants.