Sendai residents queue for gasoline in Sendai, March 14, 2011 / Roberto De Vido - Flickr Creative Commons

Build Back Better・Safe Utilities・Gas

In the Great East Japan Earthquake, the Sendai City Gas Bureau became the first gas utility in Japan to suffer severe damage to production facilities in a tsunami, and we were forced to suspend service to approximately 360,000 households in the Sendai area. However, in a little over a month, we restored service to about 310,000 households outside the area seriously damaged in the disaster. In our recovery effort, we have implemented every disaster-prevention measure to secure a safe and stable gas supply even in a disaster comparable to the recent one.

Case Study

Build Back Better・Safe Utilities・Gas

HFA Priority of Action

4. Reduce the underlying risk factors.

5. Strengthen disaster preparedness for effective response at all levels.

Context

In the Great East Japan Earthquake, emergency shutdown of the gas supply to 70,000 households was triggered in areas of high seismic intensity. In addition, the tsunami that followed the earthquake heavily damaged production facilities, and it became difficult to produce gas from liquefied natural gas (LNG), resulting in complete suspension of service to approximately 360,000 households in the area supplied by the Sendai City Gas Bureau.

Location

Areas served by Sendai City Gas Utility.

How was the problem addressed?

The Sendai City Gas Bureau did not suffer major damage in the earthquake because we had implemented earthquake countermeasures at gas production and supply facilities based on the lessons learned from the Miyagi Offshore Earthquake in the past.

Earthquake-proofing equipment such as gasholders and pipes produced big results, particularly with pipes, as we had been replacing pipes with highly earthquake-resistant steel and polyethylene pipes. The only pipes damaged in the earthquake were ones that had to be replaced. Moreover, as we have divided our supply area into blocks, we could perform disconnection, repair and improvement work for more efficient restoration of service and prevent secondary disasters through thorough security.

Our tsunami countermeasures, however, were insufficient, and the production plant that accepted deliveries of LNG by sea was flooded and became unusable. Fortunately, we had multiplexed supply routes, and pipelines for ground transportation were in place on the inland side of the plant. As they hadn’t suffered major damage in the earthquake, we were able to take in gas right away. In this way, we were able to supply gas through the pipelines, and resumed service to areas confirmed safe 12 days after the earthquake. It took nine months for tentative restoration and 13 months for full restoration of the production plant. 

During the recovery effort, staff from the Japan Gas Association and from gas utilities throughout Japan came to the aid of Sendai City staff. In addition, they supplied portable gas generators to high-priority facilities, including medical and welfare units, and provided them with an emergency gas supply until regular service was restored.

In the process of recovery, to prevent the production plant from suffering such severe damage again, we elevated the mountings of production equipment, changed the locations of openings in buildings and improved the waterproofing of the doors as countermeasures against a tsunami.

Moreover, as the pipeline terminal is located inside the production plant, it took 12 days to remove the debris from the tsunami, conduct inspections and test operations to resume service. We are constructing a new inland terminal that will not be affected by a tsunami, scheduled for completion by March 2015.

We will continue the earthquake proofing of gas pipes, which proved to be effective in the recent disaster. We are also improving efficiency by subdividing the blocks in the supply area and improving the gas supply monitoring system.

In terms of non-structural measures, we revised our disaster-preparation manual in light of the lessons learned in the recent disaster. We also disseminated the Gas Bureau’s earthquake, tsunami and other safety measures to citizens through brochures, posters, the Sendai City Newsletter, and TV commercials. Furthermore, we published disaster records in order not to forget the experience in the disaster and to pass it on to the next generation.

Results

We were forced to suspend service to approximately 360,000 households in the Sendai area. In a little over a month, however, we restored service to about 310,000 households outside the area seriously damaged in the disaster.   Moreover, in the process of recovery, we have further enhanced our earthquake and tsunami countermeasures based on lessons learned from the disaster, and are successfully reducing or eliminating disaster risk factors in the gas utility sector.

Measuring success

The earthquake countermeasures we had in place before the disaster and our multiplexing of supply routes were successful, making possible the early restoration of an essential utility.

Relevance to HFA

We were strengthening disaster preparedness in line with HFA Priority 5 before the disaster, which made an effective response possible. In addition, we are enhancing the safety of infrastructure in the process of recovery by reducing or eliminating disaster risk in line with the HFA Priority 4.

Potential for replication

We believe other gas utilities will be able to work out a plan suited to their scale, geographic surroundings and equipment.

Contribution by

Sendai City Gas Bureau.