Last July, the Tokyo government launched a Tokyo Metropolis Renewable Energy Expansion Taskforce with a 10-year goal to raise renewable energy sources to 20 percent of the metropolis’ electricity consumption by the Summer Olympics in 2020.
Rendered image of the Tokyo Main Olympic Stadium (under construction), equipped with solar and other renewable energy technology. Credit: Zaha Hadid Architects
Tokyo, known as the world’s most populous metropolis, is the largest energy consumer in Japan, consuming 10 percent of the nation’s entire electricity supply.
Homes and businesses in Tokyo consumed about 80,000 GWh of electricity in 2012. According to Mizuho Bank, of the total electricity consumption only 6 percent was supplied by renewable energy. Furthermore, most of the renewable energy was supplied via hydropower plants located outside of Tokyo owned by Tokyo Power Electric Company (TEPCO), a regional investor-owned utility. This means that only 480 GWh of renewable energy was actually generated within Tokyo.
Because Tokyo doesn’t have much land space to deploy utility-scale solar and wind farms like other parts of Japan, its efforts are focused on distributed generation systems.
To increase renewable energy sources to 20 percent from 6 percent in 10 years, Tokyo has the following goals:
- Install a cumulative capacity of 1 GW of on-site solar photovoltaic (PV) systems by 2024.
- Install 22 MW of PV on metropolis-owned buildings and facilities by 2020.
- Install 600 MW of commercial-scale co-generation system capacity by 2024.
Tokyo Solar Roof Register to Support Rooftop Expansion
According to data released by the Ministry of Economy, Trade, and Industry (METI), Tokyo has approximately 137 MW of the reserved capacity for residential PV systems under the nation’s FIT program. This is equivalent to 4 percent of the nation’s total reserved capacity and makes Tokyo the No. 9 residential solar state in the nation.
To ramp up solar PV deployment, Tokyo has created the nation’s first solar map, displaying the area of potential solar resource available on homes and buildings in the city.
The solar map, known as the Tokyo Solar Register, calculates a suitable system size (kW) and potential electricity generation (kWh) by combining information on daily solar insolation, roof-top space, roof tilt, and shade conditions on each specific home or building. This can serve as an important sales tool for PV installers and educational tool for homeowners and businesses.
Tokyo Solar Register –solar potential display. Credit: Tokyo Metropolitan Government
Although the cost of solar systems has been reduced significantly, not everyone can yet afford solar systems, so Tokyo also offers a roof rental scheme. Homeowners or businesses with adequate roof space can charge a fee for renting out their roofs to project developers.
Tokyo has the role of matchmaker: It brings together those who want to rent out the roof space and those who can invest into solar projects by taking advantage of the nation’s feed-in tariff (FIT) program. It established a web portal to connect interested parties and also provides pre-approved contract agreement forms to expedite renting processes.
As a recent example, Community Net, a developer of community housings for seniors, joined the roof rental effort by offering available roof space via one of its nursing homes. Regional project developer Tama Energy Coop, installed a 56.4-kW system after it raised funding from residents in Tama city. All electricity generated from the solar system will be sold to TEPCO under the FIT program. Tama Energy will pay Community Net 1,700 yen per kW per year (a total of 95,880 yen) for the next 20 years for the roof space.
Renewable Energy Generated within the Municipal Water Supply System
Not only is Tokyo utilizing available roof space from homes and buildings, it is also tapping into its vast water and sewage system infrastructure for renewable energy sources. In February, the Bureau of Waterworks of the Tokyo Metropolitan Government drew up a 10-year energy plan to increase renewable energy sources.
To support 13 million people, the water department uses 800 GWh of electricity per year, which is equivalent to 1 percent of Tokyo’s total electricity consumption, making the department one of the largest electricity users.
The water department plans to improve energy efficiency by at least 20 percent from 2000 levels by 2024 and install 8 MW of distributed PV capacity by 2020 and 10 MW by 2024.
It has been installing PV systems on top of water treatment plants, water reservoirs, and water supply stations. By the end of 2014, it installed a total of 6.4 MW of PV over 14 sites, and currently plans to install another 3 to 4 MW of PV systems over 25 sites.
The water department also started deploying small hydropower systems, which work within pipelines and are based on natural water flow throughout the city. As of 2014, it has deployed a total of 2.2 MW of small hydropower systems, and plans to add another 1.1 MW on six sites.
Solar Rooftop system installed in the Water Supply System in Tokyo
Hydrogen-powered Society with Fuel-Cell Technology
Besides on-site renewable energy generation, Tokyo is planning to build clean transportation and living infrastructure with hydrogen, which is currently used in Toyota’s Mirai, the world first mass-produced hydrogen fuel-cell car.
Since fuel-cell cars only emit water, not a mixture of carbon dioxide and other greenhouse gasses, the governments believes that hydrogen can be key in the development of true low-carbon societies.
Tokyo’s Council for Science, Technology, and Innovation has developed a plan to expand fuel-cell technology before the Olympics by building 35 hydrogen stations, deploying 6,000 fuel-cell cars and at least 100 fuel-cell busses, and installing 150,000 residential fuel-cell systems by 2020.
The government clearly has high aspirations for the upcoming games. “During the Olympics, I hope we can supply electricity to all the Athlete Villages from renewable energy produced locally,” said Yoichi Masuzoe, the governor of Tokyo.
The London Olympics in 2012 is reported as the most sustainable games thus far. By combining renewable energy and alternative fuels, will Tokyo be able to take the gold in sustainability?