Statements of successfull STO-makers
Our common target is to tackle all the challenges and take advantage of the opportunities to achieve a real sustainability, both for the municipal administration and the neighbors of our municipality. In this point, Solar Thermal Energy is a very important potential for our municipality. The Solar Thermal Obligation will contribute to regulate, guide and enhance the development of these systems, increasing the use of energy coming from renewable resources and reducing CO2 emissions.

Mrs. Adela Martínez Cachá - Deputy Mayor for Environment and Urban Quality at the City Council of Murcia (SP). Vice-President of the Local Agency for Energy and Climate Change  of Murcia.

Today, energy is a part of everyday life! As leaders in our community, we have the obligation to set an example of good practice in the areas of energy saving and renewable energy use, so that citizens would acknowledge the importance of each gesture intended to contribute to the health of the planet.

Eng. Lucian ILIESCU – Mayor of Giurgiu Municipality (RO)
“Solar thermal has enormous potential and low costs. Our challenge in Lazio is to convince people of the advantages deriving from its use.”

Mr. Filiberto Zaratti - Regional Minister for Environment and Cooperation among Peoples, Lazio Region (IT)

Solar energy will be
the “sun of energy”!

Professor Eduardo de Oliveira Fernandes - Secretary of State for Environment (Portuguese Government, 1984-1985), Secretary of State to the Minister of Economy for Energy and Innovation (Portuguese Government, 2001-2002), former Chairman of the Commission for Buildings Thermal Regulations at the CSOPT  (Portuguese Ministry of Public Works, 2002-2006)

Our justifiably ambitious climate protection goals are reachable. However, this needs active combatants. With the provided regulations we found a passable way for on one hand making an effective contribution to reducing CO2-emmissions and on the other hand not overburden the single citizen. People do follow, because they feel, that we have to act for protecting the climate.

Tanja Gönner - Minister for the Environment of the State of Baden-Württemberg (DE)

STO Database

Detail View:Renewable Heat Law Baden-Württemberg

Federal State of Baden-Württemberg

Ministry for Environment Baden-Württemberg Kernerplatz 9 D-70182 Stuttgart Tel: +49-(0)711-126-0ü


In November 2007 the parliament of the state of Baden-Württemberg approved its Erneuerbare-Wärme-Gesetz Baden-Württemberg (Renewable Heat Law Baden-Württemberg). Initially it effects only new residential buildings started after 1. April 2008, for which house builders are obliged to cover 20 % of the yearly heat demand with renewable heat sources. Beside the use of solar thermal, geothermal, biomass and ground coupled heat pumps the law also foresees alternative measures such as improved house insulation, cogenerators or the connection to district heating networks fed by RES or cogenerators. Starting from 1. January 2010 the law will also effect existing residential buildings.
The regulation of this law for new buildings was replaced by federal law EEWärmeG (see separate case study) on 1 January 2009.

Ordinance Facts
Ordinance titleErneuerbare-Wärme-Gesetz Baden-Württemberg (EWärmeG BW)
Type of ordinancerenewable heat law
Starting date1. April 2008, 1. January 2010 for existing buildings
Geographical areaFederal State of Baden-Württemberg, Germany
No. of inhabitants, area11 Mio, 36.000 km²

new-build residential buildings and residential homes, existing buildings in the moment of a modernisation of the heating system

Technology priorities

solar thermal, heat pumps, biooils, biogas, wood

Size of the solar heating system required0,04 m² collector area per m² of living area of the building
Alternative measuresincreased insulation of buildings, CHP, district heating by RES of CHP, PV
Executing authoritybuilding authorities on communal or district level competent for building permits
Execution mechanism

The compliance with the law is to be certified by an authorised expert and shall be presented to the competent building authority within 3 months after taking in operation of the heating system

Development and Implementation

The lion share of Germany's end energy consumption is used for heating and cooling of buildings. The national goal in this sector is a contribution of 14 % by RES, whereas the today's share is only 6 %. It is recognized that subsidies and incentives are helpful but not sufficient. After a controversial discussion at national level between heat-feed-in-tariffs and obligation models, BW was the first state taking initiative for implementing its renewable heat law.


climate and environmental protection; sustainable energy supply in BW; increase of the share of RES within the heat supply in BW; planning security for the implementation of RES heat technologies; lower cost for the end-users


The law was developed in a top-down approach, initiated by political decision makers. Hearings have been carried out with: association of communes, housing companies, manufacturers, handicraft, architects, engineers, consumers, welfare, RE suppliers, fossil fuel enterprises, unions and environmental organisations. More than 80 positions were presented and incorporated in the law. Almost all of them confirmed the overall objective of the law.


The law was enacted on 7. November 2007. The preparation phase, including three rounds of hearings had an approximate duration of 6 months.

Quality schemes productno
Quality schemes installationno
Quality schemes otherno
Flanking measures
  • The law is promoted through press releases and an information campaign
  • BW runs numerous promotion initiatives regarding RES/RUE in buildings

Random inspections are foreseen

Sanctioning feesyes, 50.000-100.000 €
Costs for implementing

approx. 1.1 Mio € per year

Monitoring and Results

Copies of all certificates are centrally collected by the Ministry for the Environment for the purpose of the evaluation of the law impact.

Quantitative results

The total building stock of BW comprises 2.2 Mio residential buildings. The yearly end energy demand for heating these buildings is approx. 72 Mrd kWh (171 kWh/m2 living area) creating 19 Mio t of CO2 emission. The expected impact of the law is to reduce these emissions by 10 %.

Costs borne by the enduser20 to 34 € per m² of living
Effects on other sectors

not yet available


not yet available

Future outlook

An evaluation of the law impact is planned for April 2011.

Lessons learned
Barriers faced and overcome

In 2008 the federal parliament Bundestag decided on the federal law EEWärmeG. The intitial plan for this law was to excempt obligatory measures from public funding.
Finally this regulation was not enacted.
The regulation of EWärmeG BW for new buildings was replaced by federal law EEWärmeG on 1 January 2009.

Success factors
  • simple and understandable approach of the law
  • compact preparation phase of approx. 6 months
  • freedom of choice between cost-effective alternatives
  • participated process of hearings with the associations
Potential for improvement

not yet available


Early coordination of legislation projects of different legislative bodies, e.g. on regional and federal level, is recommendable.

This STO was provided by:
Downloads and Links

Full text of the law (Nov. 2007, DE)

Technical sheet for solar heating systems (DE)

Infoflyer (DE)


Website of Renewable Heat Law Baden-Württemberg

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