Tokyo Metropolitan Government Working to Enhance Measures to Fight Global Warming

Electric power is a key resource for the telecommunications industry. Long before global warming prevention measures emerged as a pressing social issue, the NTT Group started work promoting its Groupwide Total Power Revolution (TPR) activities and has continuously made efforts to save energy.

In addition to the TPR campaign, NTT Communications has also established CO2 reduction targets and adopted a series of original measures in an effort to reduce power consumption. Consequently, a global warming prevention plan developed by NTT Communications' main building in Otemachi that places particular focus on energy reduction measures received high accolades from the Tokyo Metropolitan Government (TMG)'s system for fighting global warming and was introduced as an excellent example in the local body's website. This system was commenced in fiscal 2005 by TMG, and our plan was selected from approximately 1,000 such plans regarding greenhouse gas reduction submitted over a five-year period by major offices from throughout the capital.

Reducing the Amount of Energy Used to Control the Climate of Equipment Rooms

Some 90% of the energy consumed in the course of NTT Communications' entire business is used by ICT equipment such as converters, servers, and routers, as well as the cooling equipment needed to ensure their smooth operation. While such networks have in recent years become increasingly integrated, their equipment, which is typically stored in communications equipment rooms, is generating more heat than before due to their generally greater levels of energy consumption. Single rack energy consumption levels, for example, have increased to 2-4kW or even 6-8kW in some cases, as opposed to 0.4-0.6kW recorded some 20 years ago. Furthermore, equipment that generates high levels of heat is increasing with the advance of Next Generation Networks (NGN)*1. Effective cooling systems are therefore essential to ensure the proper management of such networks. In doing so, companies are employing systems whereby large-scale air conditioning systems are installed in all equipment rooms to absorb the heat output of computers. The entire room is cooled in such systems so that a person cannot stay long.

NTT Communications has always worked independently to raise the efficiency of its air-conditioning systems. Related efforts to date have seen the development of the MACS air-conditioning system*2 as well as a special cooling fan, which efficiently cools equipment rooms while using significantly less energy. We have also developed a specialized remotely controlled temperature monitoring system that enables temperatures in equipment rooms to be centrally controlled on a real-time basis. The aforementioned main building of Otemachi is one of the working examples managed by the centralized temperature control system.

• *1 NGN: Next-generation network that utilizes IP and spreads all over the telephone network
• *2 MACS air-conditioning system: Cooling system developed for use in equipment rooms that generate exceptional levels of heat

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Eliminating Inefficiency of Cooling the Entire Room

The MACS air-conditioning system employs an efficient cooling method whereby cool air is sent only to the areas that need it. Very cold air sent from an indoor unit to beneath the double flooring directly under equipment racks absorbs heat as it passes through the racks before being released into the room. By concentrating cool air to where it is needed, the MACS system effectively reduces the burden of having to cool the entire room.

Because the amount of heat generated by equipment stored in racks varies, we installed cooling fans along the air intake route of racks that generate higher heat levels (“heat points”) so that the appropriate temperature is maintained across the board.

Real-Time Temperature Monitoring of NTT Communications Equipment Rooms across the Nation

Our temperature monitoring system is another crucial element in our efforts to reduce power consumption.

The temperature monitoring system in Tokyo unifies the management of room temperatures in the equipment buildings and data centers that NTT Communications owns in about 70 locations nationwide. Remote controlled supervision technology covering wide areas by the utilization of telecommunications networks is one of NTT Communications' major strengths in the technology field.

When the temperature at any of the given monitoring points exceeds a set heat level, an alarm alerts staff, who then verify the exact location and assess whether the temperature rise is due to the activity of a specific rack or the overall air-conditioning system. This enables the appropriate measures to be taken quickly by taking advantage of our finely tuned temperature control technology using remote control.

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Solid Environmental Measures Integral to Achieving High Level of Reliability/Trust and Cost Reduction

NTT Communications has positioned “the environment,” “reliability/trust,” and “cost” at the forefront of its efforts to reduce power consumption.

Prior to April 2003 when our proprietary temperature monitoring system was installed, each communications equipment room was monitored in each building by specially appointed staff who would report the status at any given time to a central control room. The introduction of the temperature monitoring system has therefore led to tremendous labor savings as well as reduced management costs. In addition, since the alarm mechanism enables central monitoring staff to grasp the situation from a macro perspective, information-gathering capabilities are enhanced, which in turn helps prevent system malfunction and stabilizes the overall provision of services. At the same time, the system boosts service quality and reliability by way of improved response to malfunctioning.

Moreover, the system has been proven to have a positive impact on energy-saving levels, as evidenced by a test of approximately 700 of the 4,000 air-conditioning units used in NTT Communications' equipment rooms nationwide. By raising the temperature setting of communications equipment rooms by just 1, a 2% reduction in power consumption was achieved. That translates into a saving of roughly 1,900kW.

As well as the high praise of the TMG, the system has also won the approval of regional branches of the Ministry of Economy, Trade and Industry, which awarded all 16 NTT Communications' buildings nationwide more than 90 points. At the time of inspection, one METI official was overwhelmed by the temperature difference of an NTT Communications equipment room compared to equivalent rooms of other companies. Upon entering the room he said, “This room is not cold,” and showed an active interest, asking, “What kind of measures are you taking?”

Measures against Global Warming at NTT Communications Main Building in Otemachi

Composition of CO2 Emissions in FY2005 Sources CO2 emissions amount Electricity 41,558 Fuel and heat 9 Water system 12 Other 0 Total 41,579

CO2 Reduction Measures Planned by 2010 Measures Projected reduction amount (t-CO2) Introduction of MACS system, etc. 2,607 Introduction of redundant UPS 662 Introduction of super capacitors* 166 Change in temperature settings 55 Update of low wattage inverter stabilizer 13 Appropriate control of fresh air intake 8.5 Update of energy-saving fan belt 5.4 *Equipment for greater efficiency of cooling systems

Working for the Development of the Ubiquitous Information Society and the Protection of the Global Environment

On the back of current measures, there is a history of innovations that we have made as the entire NTT Group in an attempt to reduce CO2 emissions, including switching to direct current power supply to realize energy savings and the development of super capacitors for greater efficiency of outdoor units for air-conditioning systems.

“Communications equipment rooms in the buildings in city centers will become more integrated,” says a staff member in charge of promoting current energy efficiency measures. “We appreciate the fact that our business activities are becoming prosperous. At the same time, however, I am constantly aware of a sense of mission to make our utmost efforts by being aware that our business activities are having an impact from the perspective of the global environment. It is a great pleasure to have gained recognition from the Tokyo Metropolitan Government as an excellent example of the industry, in which the energy load is increasingly rising.”

These measures are only part of our activities that we conduct under the theme of global environmental protection.

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