The Bureau of Sewerage, Tokyo Metropolitan Government (TMG), was consuming 1% of electricity in Tokyo (about 80,000GWh) by its activity, and emitting 45% of the total greenhouse gases (GHG) - about 2,300kt-CO2 in 1990. A change in the way of operation for the bureau would thus contribute largely to the reduction in GHG emission, and aid in combating climate change.

From this background, the Bureau drew up the “Earth Plan 2004” in September 2004 to carry out the initiatives to combat global warming voluntarily and positively. This plan was intended to help reduce emission of GHG from 1020kt-CO2 to 950kt-CO2 between 1990 and 2009. Some of the measures proposed to reduce the emissions included micro-hydro and biomass power generation and high temperature sludge incineration.

Through the provisions of the plan, the GHG emissions by the bureau were estimated to have reduced by 50,000t-CO2. The Bureau would continue to carry out the measures set out in the Plan in order to achieve the planned reduction target by 2009.