Sustainability | Renewable Energy

Freiburg - Europe's "Solar City"

Freiburg, Germany

Solar Energy - Germany's Energiewende as seen in Freiburg


Freiburg, Europe's "solar city, has goals of achieving 100% renewable energy by 2035 and carbon neutrality for the city by 2050.

In Freiburg (as in the rest of Germany), solar energy has guaranteed feed-in tariffs (thanks to Germany's Electricity Feed-in Law).  The feed-in tariff policy supports the implementation of renewable energy sources by providing guaranteed long-term contracts to renewable energy producers.

Freiburg is a shining example of the success of Germany's energiewende. Germany's energiewende is the ongoing national transition to a low-carbon economy that got its start decades ago (feed-in tariffs became standard throughout Germany in 1991).

In addition to feed-in tariffs, Germany's ever-evolving Renewable Energy Sources Act (EEG) is credited with the rapid growth of solar and wind energy in the country. The EEG is also credited with helping to bring energiewende to greater realization.

Germany's initial version of the Renewable Energy Sources Act was introduced in 2000 - there is a new version of the EEG passed as of 2021 - now known as Germany's Renewable Energy Act. The new version of the EEG has set goals for Germany to generate large shares of renewable electricity for the country - 40-45% by 2025, 55-60% by 2035, and 80% by 2050. 

Freiburg is a great example of solar growing to its full potential in a city. 


Homes in the Sun Ship, Vauban, Freiburg

The success of solar in Germany is best evidenced by the ultra-sustainable town of Vauban.

Vauban is a city district in Freiburg in which the majority of homes run on solar energy generated on-site, mostly in the form of rooftop photovoltaics (PV) panels (as well as a supply of bioenergy).

Residences in Vauban are either passive solar energy buildings (ultra-energy efficient buildings that consume as much energy as they produce), or plus-energy buildings (producing even more energy than they consume). Homes in the Sun Ship (Das Sonnenschiff) are entirely plus-energy buildings.

Vauban is known as one of the most sustainable city districts in the world.

As the primary obstacle to increased solar deployment historically has been cost, especially with regard to solar rooftop PV, feed-in tariffs (FITs) have been extremely helpful. The fixed price for electricity and renewable energy (RE) guaranteed by German law and the RE-FITs for PV have helped solar to be cost-competitive, even before solar's major cost declines over the last several years.

Freiburg can credit solar's rapid growth in the city to the successful implementation of German energiewende policies.

For more on Vauban, read...

Europe's most sustainable city district (the city district of Vauban in Freiburg)

and - The World's Most Successful Model for Sustainable Urban Development? via Smart Cities Dive

Green Building and Sustainable Mobility in Freiburg


Market Square in Freiburg

Freiburg remains at the forefront of green building technologies, mandating that all new construction uses only the latest cutting-edge energy efficiency designs - passivhaus standards.

Energy conservation is central to all new buildings in the city, and energy efficiency retrofits are being applied to existing structures

Freiburg promotes biking and walking, which have become increasingly popular means of sustainable, alternative mobility in the city.

Biking accounts for over 1/4 of all transportation in the city. Over 300 miles of bike paths in the city help to reduce automobile use.

Freiburg features a pedestrian-only zone in the city center, where no cars are allowed.

In order to help make sustainable modes of transit even more attractive, all roads in Freiburg, other than major roads, have a max speed limit of 50 km/h (often lower speed limits are mandated).

The city offers the Regio Card (Regiokarte), which enables residents full access to all of Freiburg's trams, streetcars, trains, and buses. Increasing city residents' ease of access to Freiburg's mass transit options, 70% of the population live within 1/2 km from a tram stop.

This snippet from BBC summarizes some of Freiburg's major accomplishments in sustainability over the last few decades:

Freiburg has quickly developed as an environmental economics and solar research hub with a packed green CV:

• 1994: Builds Heliotrope: one of the first plus energy homes in the world (producing up to 5 times the amount of energy it requires) - a rotating solar home with composting toilets and a slew of modern cutting-edge energy efficiency technologies (such as a large roof-mounted solar array and solar thermal pipes)

• 2002: Elects Germany’s first Green Party mayor of a large German city, Dieter Salomon

• 2012: Named most sustainable city in Germany

• 2017: New Town Hall becomes world’s first public building producing surplus energy"  [quote from]

Freiburg's Town Hall

Here's more information about Freiburg's Town Hall:

"During the course of the year, the building generates more energy than it consumes. The excess energy is fed into the city grid. In accordance with the strict criteria of the PassivHaus standard, the primary energy demand of the town hall for heating, cooling, ventilation, and hot water supply [is sourced from renewable energy and passive heat gains].

...electric energy is generated by photovoltaic panels on the roof and in the facade. The energy for cooling and heating is obtained from a geothermal installation. Thermal mass activation is used for heating, which can be individually controlled in each office. The mechanical ventilation has been enhanced by highly efficient heat recovery."  [quote from]

Urban planning in Freiburg




Arial view of the city of Freiburg at the foothills of the Black Forest

Green urban planning is paramount in Freiburg, and the city has designated green areas as a priority in land-use decisions.

Large sections of the city remain protected as parks, forests, or green landscaped spaces - a big reason why biking and walking remain so popular in the city. 

Freiburg is near the southwest end of the Black Forest, and near France and Switzerland. Another nickname Freiburg has earned is the 'capital of the Black Forest'.

Freiburg is connected to the Black Forest by rail and is seen as the southern gateway to the Black Forest. The city's full name is Freiburg im Breisgau, with the "Breisgau" referring to a region in southwest Germany between the Rhine River and the foothills of the Black Forest.

Freiburg is a wonderful place for both students and eco-minded people; as the city has a great university, plentiful renewable resources, green buildings, and other sustainability-themed features.

The city is home to the University of Freiburg, which accounts for some of the city's over 230,000 residents, some of whom move from all over Europe to attend the University.

Many people move to Freiburg to live in an ultra-eco-conscious city. Residential recycling programs in Freiburg go beyond standard measures, as compost (kitchen and garden waste) is also collected.

Freiburg is also known as a resort town, in addition to a university city and Europe's 'solar city'. Freiburg not only offers plenty of cultural events, museums, and historical architecture for visitors; Freiburg is at the foothills of a part of the Black Forest that is known for skiing, mountain biking, camping, sailing, and hiking.

Here's a brief snippet from the World Wildlife Foundation summarizing green spaces in Freiburg -

"Two-thirds of Freiburg's land area is devoted to green uses. Just 32% is used for urban development, including all transportation. Forests take up 42%, while 27% of land is used for agriculture, recreation, water protection, etc..."  [quote from  -]

Bioenergy in Freiburg


In addition to using solar power as a major energy source, Freiburg uses biomass for a significant share of the city's energy needs. The majority of Freiburg consists of woodland, green spaces, and agricultural lands - there are over 5000 hectares of forest surrounding the city.

In Freiburg, bioenergy (biogas, biofuels, renewable electricity, and heat) is generated from wood and forestry byproducts, but the city also turns waste into biomass energy to power residences and businesses.

Biomass plants in Freiburg substantially rely on methanization; a process that turns organic matter into biogas (in the case of Freiburg - mostly forestry/agricultural waste, and waste from residential/ commercial buildings). Methanization-based biomass plants at the edge of the city are fed with collected organic waste to generate energy (over 36,000 tons per year of waste-to-energy - W2E) provided by city residents (mostly farming, kitchen, and garden waste).

Wood is burned, in addition to waste, in the biomass plant in the city district of Vauban. Landfill gas and organic waste are both used in the other biomass plants in Freiburg. These biomass plants, along with another biomass plant in Freiburg that uses mostly rapeseed oil to produce biodiesel, are combined heat and power (CHP, also known as cogeneration) plants that supply district heating, in addition to electricity in the city.

What are other renewable energy sources in Freiburg?  


In addition to biomass power plants in Freiburg, are smaller anaerobic digesters on farms in Freiburg.

Biomass plants and solar energy are not the only sources of renewable energy in Freiburg. Other than solar and biomass, small wind farms and small hydropower projects also provide energy to the city (wind and hydroelectricity provide a relatively small share of Freiburg's energy, and conventional energy sources provide the rest of Freiburg's energy needs).

This quote provides a summation of renewable energy generation in Freiburg:

  • BiomassBiomass has the largest share of Freiburg’s renewable electricity generation. In Freiburg, organic waste has been collected separately since 1997.  A biogas installation transforms the organic waste into biogas and compost. Organic waste from Freiburg’s households is fed into a digester that produces biogas and compost.
    • CHP - Biogas is burned in a CHP plant 20 km north of Freiburg lies a unique mechanical-biological waste treatment plant, one of a kind in the world that has been patented within Europe. Since 2006 it has been producing valuable materials from left-over waste, alternative fuels, and mineral products as well as biogas that is used for electricity and district heating.
    • Waste-to-Energy - When Freiburg landfill was closed, a modern garbage incineration started functioning.  It has an annual capacity for treating 150,000 tons of household and business waste and produces electricity [through W2E] for about 25,000 households.  Its four-stage flue gas cleaning system ensures that strict emission limits are adhered to."
  • Solar - Freiburg has 150,000 m² of solar cells, panels, and arrays - on rooftops and properties - producing over 10 million kWh/year. New "plus energy homes" produce more energy then consumed by the buildings, and as a result, have lower utility bills, are able to be energy generators for surrounding buildings, or extra energy can even earn profits of up to ~ €6000 Euros per year for their residents. [Vauban is a great example of a town in Freiburg in which plus-energy home owners sell back energy to the municipality, for use in other parts of the community.]
  • Other renewable energy and Freiburg's sustainable transportation - The [relatively few] windmills in the city are situated on hilltops...small, eco-friendly run-of-the-river [hydroelectric] facilities are on the river and on smaller canals and streams. Since January 2009, Freiburg’s 60 trams have been running on 100% renewable energy. Another notable aspect of Freiburg’s transport policy is traffic calming. For most streets (other than main streets) the speed limit is 30 km (19 mi) per hour. On some streets cars can travel no faster than walking speed, and children are allowed to play in the streets.  [quote from  -]

The city of Freiburg was home to the Solar Summit 2013, which focused on the global energy transition, grid integration and grid stability, storage solutions, and energy management. Energiewende was in full swing during Freiburg's Solar Summit. 

Solar Summit Freiburg 2013 was an event for investors, scientists, utility executives, and government officials worldwide. The Freiburg Solar Summit followed a Solar Heating and Cooling Summit in Freiburg, in which new solar thermal technologies were highlighted. 

Homes in Vauban


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