(private and commercial) were heated by district heating, according to the Swedish association of district heating. The city of Växjö reduced its emissions from fossil fuels by 34% from 1993 to 2009. This was to achieved largely by way of biomass fired district heating. Another example is the plant of Enköping, combining the use of short rotation plantations both for fuel as well as for phytoremediation. 47% of the heat generated in Swedish district heating systems are produced with renewable bioenergy sources, as well as 16% in waste-to-energy plants, 7% is provided by heat pumps, 10% by flue-gas condensation and 6% by industrial waste heat recovery. The remaining are mostly fossil fuels: oil (3%), natural gas (3%), peat (2%), and coal (1%). Because of the law banning traditional landfills, waste is commonly used as a fuel. Ukraine United Kingdom In the United Kingdom, district heating became popular after World War II, but on a restricted scale, to heat the large residential estates that replaced areas devastated by the Blitz. In 2013 there were 1,765 district heating schemes with 920 based in London alone. In total around 210,000 homes and 1,700 businesses are supplied by heat networks in the UK. The Pimlico District Heating Undertaking (PDHU) first became operational in 1950 and continues to expand to this day. The PDHU once relied on waste heat from the now-disused Battersea Power Station on the South side of the River Thames. It is still in operation, the water now being heated locally by a new energy centre which incorporates 3.1 MWe / 4.0 MWth of gas fired CHP engines and 3 × 8 MW gas-fired boilers. One of the United Kingdom's largest district heating schemes is EnviroEnergy in Nottingham. The plant initially built by Boots is now used to heat 4,600 homes, and a wide variety of business premises, including the Concert Hall, the Nottingham Arena, the Victoria Baths, the Broadmarsh Shopping Centre, the Victoria Centre, and others. The heat source is a waste-to-energy incinerator. Scotland has several district heating systems with the first in the UK being installed at Aviemore and others following at Lochgilphead, Fort William and Forfar. Sheffield's district heating network was established in 1988 and is still expanding today. It saves an equivalent 21,000 plus tonnes of CO2 each year when compared to conventional sources of energy – electricity from the national grid and heat generated by individual boilers.