Our Campus – Ecology & Sustainability

Environmental School with a Focus on ESD

Education for Sustainable Development (ESD) is now an internationally recognized educational goal and is firmly anchored in UNESCO’s Education 2030 framework. At the heart of this is Sustainable Development Goal (SDG) 4.7: All learners should acquire the knowledge, skills, and attitudes that enable them to act responsibly and actively help shape a sustainable future.

ESD therefore means much more than just environmental education. Students should learn to think critically, solve problems, take responsibility, act democratically, and understand the impact of their own actions on other people, regions, and future generations.

Building resilience for the challenges of the future

Topics such as environmental and climate protection, sustainable consumption, global justice, social responsibility, health, economic thinking, and social participation are just as much a part of this as independent learning, cooperation, and a forward-looking perspective. The goal is a school that not only imparts knowledge but also empowers young people to actively, thoughtfully, and responsibly help shape the challenges of the future.

At Steinmühle School & Boarding School, education for sustainable development is already evident in many areas of school life. Sustainability is reflected, among other things, in the use of renewable energy sources such as the school’s own hydroelectric power plant, the expansion of solar power and heat pumps, and the vision of a climate-neutral school. In construction as well, Steinmühle consciously prioritizes wood, eco-friendly building materials, and regional companies. Natural retention areas, the school’s contribution to the “Living Lahn” project, and the new fish ladder—which supports waterway conservation—further illustrate the close connection between learning, nature, and responsibility on campus.

Hydropower

When the Steinmühle, located directly on the Lahn River, was founded in 1949, the water rights were acquired along with the property. If left unused, these rights would lapse—a situation that repeatedly prompted the Buurman family, one of the co-founders, to take action.

What to do?
The option of electrifying the millwheel was quickly ruled out.
In 1982, the decision was made to build a hydroelectric power plant. This was the wish of teacher and co-founder Gerhard Buurman, who envisioned a self-sufficient and environmentally friendly power supply.
Today, two turbines—one rated at 70 kilowatts and the other at 110 kilowatts—generate an average of 145 kilowatt-hours of electricity per hour. The small turbine has been in operation for 44 years and is only supplemented by the large turbine when there is sufficient water.

The annual electricity target at Steinmühle is easily met. In 2024, total annual output was 675,000 kilowatt-hours—compared to Steinmühle’s annual electricity demand of 350,000 kilowatt-hours. During peak periods, hydropower generates 160 to 170 kilowatt-hours of electricity per hour.

So far, so good. Due to a lack of storage capacity, the electricity that cannot be consumed immediately is fed into the public grid. Currently, this amounts to 145,000 kilowatt-hours—for a feed-in tariff of 6.9 cents per kilowatt-hour.

Since the demand for kitchen operations in the morning is significantly higher than the electricity currently being generated from ongoing operations, the Steinmühle ultimately has to purchase additional electricity despite the surplus. Due to the low feed-in tariff, a financial burden remains—though it is accompanied by the certainty and satisfaction of having saved electricity and reduced CO2 emissions in recent years.

Nevertheless, for financial reasons that are by no means insignificant, Steinmühle is aiming to acquire a battery storage system for the future.
Options are currently being evaluated and quotes are being solicited.

Hydropower

When the Steinmühle, located directly on the Lahn River, was founded in 1949, the water rights were acquired along with the property. If left unused, these rights would lapse—a situation that repeatedly prompted the Buurman family, one of the co-founders, to take action.

What to do?
The option of electrifying the millwheel was quickly ruled out.
In 1982, the decision was made to build a hydroelectric power plant. This was the wish of teacher and co-founder Gerhard Buurman, who envisioned a self-sufficient and environmentally friendly power supply.
Today, two turbines—one rated at 70 kilowatts and the other at 110 kilowatts—generate an average of 145 kilowatt-hours of electricity per hour. The small turbine has been in operation for 44 years and is only supplemented by the large turbine when there is sufficient water.

The annual electricity target at Steinmühle is easily met. In 2024, total annual output was 675,000 kilowatt-hours—compared to Steinmühle’s annual electricity demand of 350,000 kilowatt-hours. During peak periods, hydropower generates 160 to 170 kilowatt-hours of electricity per hour.

So far, so good. Due to a lack of storage capacity, the electricity that cannot be consumed immediately is fed into the public grid. Currently, this amounts to 145,000 kilowatt-hours—for a feed-in tariff of 6.9 cents per kilowatt-hour.

Since the demand for kitchen operations in the morning is significantly higher than the electricity currently being generated from ongoing operations, the Steinmühle ultimately has to purchase additional electricity despite the surplus. Due to the low feed-in tariff, a financial burden remains—though it is accompanied by the certainty and satisfaction of having saved electricity and reduced CO2 emissions in recent years.

Nevertheless, for financial reasons that are by no means insignificant, Steinmühle is aiming to acquire a battery storage system for the future.
Options are currently being evaluated and quotes are being solicited.

Photovoltaics

Another issue related to renewable energy has been a concern for Steinmühle for quite some time: the roofs of its own buildings have been equipped with solar panels. The most recent upgrade took place in the summer of 2019.

The School Association, as the governing body of Steinmühle, makes the rooftops of the School Forum and the “Atrium” building available to the Sonneninitiative association. The association, in turn, makes them available to interested citizens who wish to generate environmentally friendly solar power there.

Sonneninitiative e.V., an association based in Marburg, organizes the project and handles the billing. It operates numerous community solar power plants.

Photovoltaics

Another issue related to renewable energy has been a concern for Steinmühle for quite some time: the roofs of its own buildings have been equipped with solar panels. The most recent upgrade took place in the summer of 2019.

The School Association, as the governing body of Steinmühle, makes the rooftops of the School Forum and the “Atrium” building available to the Sonneninitiative association. The association, in turn, makes them available to interested citizens who wish to generate environmentally friendly solar power there.

Sonneninitiative e.V., an association based in Marburg, organizes the project and handles the billing. It operates numerous community solar power plants.

Our Cuisine: Organic – Local – Fair Trade

Things are always happening in the Steinmühle’s kitchen and bistro: Six suppliers deliver 109,000 kilograms of food to the campus in 446 shipments each year. This food serves approximately 900 students, including 100 boarding students. But the campus also feeds the teaching staff—which numbers well over 100—the boarding school educators, the administration, the housekeeping staff, and everyone else who works for the benefit of Steinmühle School & Boarding School. That’s a big task for Head Chef Sebastian Riehl and his team!

This is a major undertaking, and not just in terms of quantity. Just as we do in every other aspect of school and boarding life, we prioritize quality. The ingredients in our raw materials, meals, and beverages come from organic and regional sources whenever possible. The Fairtrade seal indicates that fair trade is important to us.

Pasta, rice, lentils, couscous, bulgur, coffee: They’re all organic.
Cheese, milk, yogurt, and quark come from Hofgut Friedelhausen, which operates according to Demeter standards.
The fish served at Steinmühlen comes from MSC-certified fisheries.
The eggs come from right next door, from the Brusius family’s mobile chicken coop in Cappel.

By the way:

For our kitchen team, using salt and sugar sparingly is a matter of course.

We clean our kitchen using eco-friendly cleaning products that carry the EU Ecolabel.

The menu is balanced and includes one vegetarian day, “Meatfree Monday.” Fish is served once a week.