Solar Energy - Germany's Energiewende as Seen in Freiburg
A town in Freiburg, at the foothills of the Black Forest
Freiburg is near the southwest end of the Black Forest in Germany, near France and Switzerland. A 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 the region in southwest Germany between the Rhine River and the foothills of the Black Forest.
Freiburg,Europe's "solar city", has goals of achieving 100% renewable energy by 2035 and carbon neutrality for the city by 2050.
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, an economy based on renewable energy and electrification, that got its start decades ago (the German Electricity Feed-in Law was passed in 1991, and feed-in tariffs in Germany were strengthened by the Renewable Energy Sources Act in 2000).
Freiburg is a great example of solar growing to its full potential in a city.
Freiburg, Germany
The feed-in tariff policy supports the implementation of renewable energy sources by providing guaranteed long-term contracts to renewable energy producers.
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 (Erneuerbare-Energien-Gesetz) is also credited with helping to bring energiewende to greater realization.
The original 2000 version of the EEG had 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.
Due to the EEG, the share of electricity provided by renewable energy in Germany has increased from around 6% in 2000 to over 50% in 2023.
Germany has raised the ambition in the latest version of the EEG - for instance - a goal of 80% renewable energy for the country by 2030.
The success of solar in Germany, and of energiewende policies, 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 solar photovoltaic (PV) panels (as well as a supply ofbioenergy).
Residences in Vauban are either passive solar energy buildings (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, Vauban
Homes in the Sun Ship (Das Sonnenschiff), a group of residences in a co-op community in the town of Vauban, are entirely plus-energy buildings. The extra energy from plus-energy buildings can be sold back to and used by the local electricity grid.
Vauban is known asone 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 rooftop solar 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.
Freiburg remains at the forefront of the implementation of green building technologies. The city mandates 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 features pedestrian and cycling-only zones in the city center, where no cars are allowed.
Freiburg promotes biking and walking, which have become increasingly popular means of sustainable, alternative mobility in the city. Over 1/3 of residents in Freiburg do not even own a car.
Biking accounts for over 1/4 of all transportation in the city. Over 250 miles of bike paths in the city help to reduce automobile use.
In order to help makesustainable modes of transit even more attractive, roads in Freiburg, other than major roads, have a max speed limit of 30 km/h (often lower speed limits are mandated) - this is in addition to other traffic calming strategies.
The majority of transit in Freiburg is done by pedestrians, cyclists, or via public transit.
Electric tram in Freiburg
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 quote from the 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:
Heliotrope - the world's first rooftop solar-based plus-energy home
• 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). [The Heliotrope was designed by the same architect that designed Vauban's Sun Ship - Rolf Disch].
• 2002: Elects Germany’s first Green Party mayor of a large German city, Dieter Salomon
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."
Arial view of a town in 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 (a majority of the land in Freiburg) remain protected as parks, forests, agricultural land, or green landscaped spaces; a big reason why biking and walking remain so popular in Freiburg.
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 a portion 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 quote from the World Wildlife Foundation summarizing green spaces in Freiburg -
"Two-thirds ofFreiburg'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..."
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 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, this is mostly forestry/agricultural waste, and waste from residential/ commercial buildings).
Methanization-based biomass plants at the edge of the city are fed with organic waste in order to generate energy (over 36,000 tons per year of waste-to-energy) 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 biomass-fueled combined heat and power (CHP) plantsthat supply district heating, in addition to electricity, to the city.
Freiburg's buildings consist of a significant share of energy-efficient buildings (with very low energy demands) heated by heat pumps and/ or the city's district heating network, which is fed by biomass-based CHP plants.
What are Other Renewable Energy Sources in Freiburg?
In addition to biomass power plants in Freiburg, there are smaller anaerobic digesters on farms in Freiburg. Anaerobic digestion is a process of producing energy from waste and other organic materials typically used in biomass/ biofuel production.
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:
"Biomass - Biomass 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 combined heat and power 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 (W2E) - 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."
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. Energiewendewas in full swing during Freiburg's Solar Summit.
