Copenhagen is recognized as one of the most environmentally friendly cities in the world. As a result of its commitment to high environmental standards, Copenhagen has been praised for its green economy, ranked as the top green city for the second time in the 2014 Global Green Economy Index (GGEI).

In 2001, a large offshore wind farm was built just off the coast of Copenhagen at Middelgrunden. It produces about 4% of the city’s energy. Years of substantial investment in sewage treatment have improved water quality in the harbour to an extent that the inner harbour can be used for swimming with facilities at a number of locations. Copenhagen aims to be carbon-neutral by 2025. Commercial and residential buildings are to reduce electricity consumption by 20 percent and 10 percent respectively, and total heat consumption is to fall by 20 percent by 2025. Renewable energy features such as solar panels are becoming increasingly common in the newest buildings in Copenhagen. District heating will be carbon-neutral by 2025, by waste incineration and biomass. New buildings must now be constructed according to Low Energy Class ratings and in 2020 near net-zero energy buildings. By 2025, 75% of trips should be made on foot, by bike, or by using public transit. The city plans that 20–30% of cars will run on electricity or biofuel by 2025. The investment is estimated at $472 million public funds and $4.78 billion private funds.

The city’s urban planning authorities continue to take full account of these priorities. Special attention is given both to climate issues and efforts to ensure maximum application of low-energy standards. Priorities include sustainable drainage systems, recycling rainwater, green roofs and efficient waste management solutions. In city planning, streets and squares are to be designed to encourage cycling and walking rather than driving. Furthermore, the city administration is working with smart city initiatives to improve how data and technology can be used to implement new solutions that support the transition toward a carbon-neutral economy. These solutions support operations covered by the city administration to improve e.g. public health, district heating, urban mobility and waste management systems. Smart city operations in Copenhagen are maintained by Copenhagen Solutions Lab, the city’s official smart-city development unit under the Technical and Environmental Administration.