Box 3.5 Energy Planning in Mannheim

(for example, covering the same urban area with both natural gas and district heating networks, which has occurred in China and some Eastern European cities). In China, the scarcity of natural gas, which is piped into households for cooking and water heating, means that natural gas distribution represents a relatively expensive investment for gas companies. Space heating is therefore normally provided by separate district heating systems. In Eastern European cities, natural gas has been introduced more recently and is competing with established district heating systems. While competition is normally good in markets, it is not necessarily benefi cial in this case because it is undermining the capital investment in district heating systems. In Germany, many cities do not allow utilities to provide district heating and natural gas services in the same area because, to a large extent, both energy carriers provide the same service—space heating (box 3.5).

The future of urban energy supply will still lie in network-based systems that facilitate the adoption of distributed energy generation and decentralized renewable power systems. Thus, if long-term gas supplies are secure, urban energy infrastructure investments should focus on developing modern power grids and natural gas networks. In densely populated cold climate cities in which natural gas is scarce or unavailable, the development of district heating systems is the key to reducing air pollution and improving space heating services. The planning and engineering of specifi c network-based systems (that is, electric, gas, or heat) have become sophisticated, and technologies are still advancing. For urban planners, the real challenge and the essential task involve fostering the integration and adaptation of network-based energy infrastructure to enhance the effi ciency of energy supply and facilitate the uptake of distributed energy resources and other local lowcarbon energy sources (for example, methane from landfi lls and wastewater treatment plants).

Policies, Legislation, and Regulations

In general, national and regional legislators and governments are responsible for energy sector policies and regulations. Cities have limited infl uence on policy and legislative processes except as regards locally based energy services that require government interventions, such as

BOX 3.5

Energy Planning in the City of Mannheim

To strengthen energy planning, Mannheim, Germany has been divided into zones based on the type of energy network. A utility owned by the municipality supplies natural gas, electricity, and district heating. Electricity is universally supplied. Space heating is supplied using natural gas, district heating, or electricity. In areas with greater heat loads, district heating is provided and is the least costly option. In areas with medium -size heat loads, natural gas provides decentralized heating. Areas with low heat demand are supplied using offpeak electrical heat storage devices. Large customers such as department stores, hotels, and offi ce buildings are cooled using absorption chillers linked to the district heating system.

Source: Bernd Kalkum.

By avoiding parallel gas and district heating networks, least cost energy provision is achieved. In zones served by district heating, gas is no longer offered. Electricity and district heat are produced by a combined heat and power plant in the city. The same utility operates public transportation and supplies water. In this way, energy demand and production may be optimized to meet the most important needs of the city.

An important result of Mannheim’s plan has been the conversion to cleaner energies. In 1983, 37 percent of all residential buildings were heated by coal or oilfi red heating units. In 1995, this share had dropped to less than 10 percent. In addition, sulfur dioxide emissions have been reduced by about 85 percent, mononitrogen oxides by 40 percent, and carbon dioxide by about 30 percent.