Photo/IllutrationThe central area of Sapporo's Susukino district fell dark after an earthquake in southwestern Hokkaido on Sept. 6 caused a widespread power outage. (Asahi Shimbun file photo)

The major blackout that spread across Hokkaido following a great earthquake in September should provide many lessons on minimizing power supply damage during disasters and the need for risk distribution.

An investigation committee of the government-authorized Organization for Cross-regional Coordination of Transmission Operators, Japan (OCCTO) has analyzed the cause of the quake-induced blackout, which struck nearly all of Hokkaido, along with stopgap recurrence prevention measures.

OCCTO called on Hokkaido Electric Power Co. to improve operations on many fronts, including strengthened coordination among its power stations.

For starters, all possible measures should be taken to get through the impending winter peak in power consumption.

The blackout called into question the wisdom of Hokkaido Electric’s centralized operation, whereby the Tomato-Atsuma thermal plant, damaged by the quake, was covering half of all power demand in the regional utility’s service area.

The investigation committee, however, said the centralized arrangement cannot be called inappropriate. That view is based chiefly on the analysis results saying the area-wide blackout was caused by composite factors, which included not only generator shutdowns at the Tomato-Atsuma plant but also power transmission line accidents.

However, many questions remain unanswered.

A blackout also followed the Great East Japan Earthquake and tsunami of 2011. Was Hokkaido Electric sufficiently prepared for a possible nose dive in its supply capacity?

Hadn’t the utility, in a sense, given shortsighted priority to a low power generation cost in growing more dependent on the Tomato-Atsuma plant, thereby slowing down maintenance and development of other power stations and facilities?

The investigation committee failed to squarely address those issues. The background factors and fundamental issues have not been sufficiently rooted out.

The industry ministry and OCCTO have a responsibility to keep investigating the matter from a broad perspective and to single out problems and their solutions. They should share any lessons learned with the power industry so they can develop a disaster-resistant power supply grid.

The Hokkaido blackout brought to light the vulnerability of a “large-scale, centralized” type of power supply system. The power supply capacity can drop immediately once a large thermal plant or a nuclear plant is affected by a disaster.

Some strips of land in greater metropolitan areas, including along the coast of Tokyo Bay, contain a concentration of power plants. Major utilities should inspect their power sources and grids and pursue risk-reduction measures.

In the mid- to long-term perspective, emphasis should be on rebuilding power infrastructure to bring it closer to an “autonomous, distributed” type, wherein power demand is procured locally to the greatest extent possible.

More power should be generated by solar, wind, biomass or other plants, depending on the characteristics of the respective terrains. Low-cost storage batteries and other appliances should be developed and circulated broadly to serve as a source of regulating power and leveling out variations in output due to the weather.

A broad-area power grid should be developed so utilities can mutually complement their excesses and shortages.

Similar restructuring efforts will require much time and money. Another challenge will be how to strike a balance between economic efficiency and stable supply.

To solve those problems, the government should create a suitable environment that allows businesses to invest in plant and equipment as well as research and development.

--The Asahi Shimbun, Oct. 26