With the energy grid in east Japan weakened after the Great East Japan Earthquake and subsequent nuclear crisis, the Roppongi Hills complex in Tokyo is gathering attention for its energy self-sufficiency, which operators say makes it immune to blackouts.
Since it opened in 2003, the facility -- which houses around 20,000 people working at offices, stores and a hotel as well as around 2,000 residents -- has covered its own power needs.
"I've heard that some companies moved their call centers to the Kansai district because of power shortages, but our company hasn't had to do anything like that," says Yoshiaki Yoshimatsu, head of general affairs at PC maker Lenovo, whose Japan branch is based in the Roppongi Hills complex.
Koichi Hasegawa, managing director at securities dealer Barclays Capital, says, "If you lose power, your operations halt. Our company won't move into a building that lacks a generator."
Aiming to create a facility that could withstand disasters, Mori Building Co., which manages the complex, spent around 10 billion yen to set up equipment including underground gas turbines with a total output of around 39,000 kilowatts. Waste heat from the generator is used in the building's heating and cooling systems. If gas lines are cut and the power generator can't be used, the facility uses power from Tokyo Electric Power Co. (TEPCO). If that is unavailable, there is an emergency kerosene power generator. Together, the options give the facility two layers of power backup.
Roppongi Hills did not lack power after the disaster, but even so, energy-saving measures like lowering the lights throughout the complex were introduced, saving around 4,000 kilowatts during the day (around 1,100 homes' worth of electricity) and around 3,000 kilowatts during the night. This extra energy was passed on to TEPCO through April. Since then, power usage continues to be 15 percent lower than before, and it is said that residents have become more conscious of their energy usage, with dim lighting having become the norm. In summer, the facility will once again send leftover electricity to TEPCO.
Through April and May, observers from local governments and corporations visited almost 20 times to study the facility's power self-sufficiency. Naoki Inose, vice-governor of Tokyo, wrote on his blog that he "thought that (a visit) would help in thinking about how Tokyo uses energy."
Inquiries from companies about renting space in the facility have also increased.
"The reason used to be that they wanted to do business in Roppongi, but now companies are looking at our ability to provide stable energy," says a Mori Building PR official.
Norihisa Hijikata of Tokyo Gas, which supplies the Roppongi Hills complex, says, "Until now, the focus has been on building power systems that can meet the energy needs of economic growth, but from now on there will probably be more discussion about diversifying electricity sources."