Creating a city aware of the need for saving energy and protecting the environment

Full consideration is given to the environment and saving energy at Roppongi Hills, and every effort is made to bring more greenery back to the center of the city and to build energy-saving power supply systems.

Planting vegetation

Approximately 29% of the Roppongi Hills area is surrounded by greenery.
Roppongi Hills Mori Tower and the residence buildings and other facilities have been built vertically and very high. This is an effective way to create more open space for parks, plazas, and walking paths. In addition, positive efforts have been made to plant vegetation on the rooftops of the buildings.
Planting vegetation is viewed as a way to help prevent global warming in the city (including the heat island phenomenon). As a result of these efforts, Roppongi Hills is 10-15°C cooler than other nearby areas.

Photography: Skymap Co., Ltd.

Keyakizaka Complex Rooftop Garden

A rooftop garden (1,300 m2 in area) that has been designed with the theme of a traditional Japanese farm has been created on the roof of the Keyakizaka Complex (Toho Cinemas Roppongi Hills). Viewing the rooftop garden where rice, vegetables and other plants are cultivated and animals are raised, visitors to the complex can gain a feeling for the food culture of Japan along with other aspects of traditional Japanese culture. In this way, visitors are also encouraged to think about the environment and how food is produced (normally not open to the public). The active efforts to plant vegetation on the rooftops at Roppongi Hills contributes to mitigating the heat island phenomenon and the burden on the environment from the mid-summer heat. This is an example of the city’s environmental protection policy.

Large-scale cogeneration

Roppongi Hills utilizes city gas, and gas turbines are used to generate electric power. The waste heat generated is supplied to the area for use in air conditioning systems. This results in a 20% reduction in primary energy consumption, a 27% reduction in CO2 emissions, and a 45% reduction in nitrogen oxide (NOx) emissions. To provide a backup source of electric power for times of disaster or other emergencies,​ ​
in addition to the supplementary electricity received from the electric power company, Roppongi Hills has set up a system that allows kerosene to be used as a fuel to generate power for a period of 72 hours.

Reusing water (gray water system and rainwater utilization system)

Wastewater of relatively good quality, including the water drained from restroom sinks, baths, and air conditioner drains in each Roppongi Hills building (excluding the residences) is recovered and sent through a treatment process to bring it to a quality level where it can be reused. It is then supplied to each building as gray water for such purposes as flushing toilets. This reduces demand for clean water (tap water) by approximately 30%.

Roppongi Hills has installed water storage tanks to save rain water at 14 locations in the area. This has resulted in a 28% reduction in the volume of wastewater compared to the volume before the area was redeveloped.

Solar power generation

As part of its effort to contribute to mitigating global warming, Roppongi Hills has installed a solar power system that generates 10 kilowatts of energy. The electricity generated is used for the lighting in the museum cone. Lithium ion storage batteries are linked to this to provide a reserve power source that can be used during power outages.​ ​
A video showing the Roppongi Hills vision of using solar power systems to generate electricity is combined with a real-time indication of the amount of power being generated.

(Technical cooperation) Life Solutions Company, Panasonic Corporation

Sorting trash for collection and recovery

Trash generated at every building in Roppongi Hills is sorted before collection to enable efficient and environmentally friendly disposal and recovery.
Waste paper is sorted according to each of the methods applied for 100% salvage and further use as a resource.​ ​