The Tokyo government switched last week from fossil fuel to biomass energy to supply around 80 percent of electricity in its Shinjuku Ward headquarters, as part of efforts to achieve net zero carbon dioxide emissions in the metropolis by 2050.
Thirty million kilowatt hours of renewable energy will be supplied to the Tokyo government's two main buildings and the metropolitan assembly hall, or approximately 80 percent of the complex's maximum annual energy needs, officials said, adding that the switchover took place Thursday.
"With the Tokyo government taking the lead, we hope to speed up initiatives (to achieve the zero emission goal) in the private sector," an official in charge of the project said.
In June, the Tokyo government called for tenders for energy suppliers, with bid evaluations focused on both cost and environmental aspects. The contract, which was awarded to Hitachi Zosen Corp. for 632 million yen ($5.9 million), will run to September next year.
Hitachi Zosen purchases energy produced by waste power generation at incineration plants within and outside Tokyo, supplying the biomass portion to the city government.
CO2 is emitted when the plant material used as fuel is burned to produce energy, but this is offset by the absorption of the heat-trapping gas in the atmosphere via photosynthesis during the plants' growth. As such, the process is considered to result in a net zero carbon footprint.
By switching its source of electricity from gas and coal to renewable energy, the Tokyo government has seen a 15 percent increase in costs, the officials said.
The remaining 20 percent of electricity is powered by gas supplied by a separate company under a long-term contract, due to the necessity of having multiple power sources in the event of a disaster, they said.
In fiscal 2017, power generated by renewable energy sources accounted for around 14 percent of the total used in Tokyo, including private businesses. Tokyo will continue to promote the use of renewables to achieve the goal of raising the ratio to 30 percent by 2030, according to the officials.