Amid the devastation caused by Typhoon Faxai in Chiba Prefecture last month, an estimated 2,000 utility poles were destroyed or damaged, severing power lines and causing large-scale blackouts in hundreds of thousands of households. It took more than two weeks to restore electricity to most of the affected areas, leaving large numbers of residents without water and power for an extended period. The prolonged outages provide yet another reason to expedite lagging efforts to bury power cables underground.
In fact, extensive and prolonged blackouts due to the havoc caused by typhoons are becoming more common as extreme weather conditions have become more frequent in recent years.
A powerful typhoon that hit the Kansai region in September last year knocked down more than 1,000 utility poles, causing blackouts for 2.2 million households. It took 17 days to get the grid fully back online. Erecting new utility poles and reconnecting severed cables is a time-consuming process.
Moving electricity cables underground is an effective measure to protect power lines from damage during major disasters. Unfortunately, Japan lags far behind many other countries in this effort. Utility poles toppled by a typhoon or a large earthquake can also block emergency vehicles such as ambulances and fire engines, impede the evacuation of residents and hamper reconstruction efforts.
Last year, the government set a target of moving 1,400 km of power transmission lines underground in the three years to 2020. The massive cost hampers such measures, but efforts should be sped up by exploring cheaper methods and by choosing priority areas that are particularly vulnerable to disasters.
Following the devastation of World War II, Japan placed priority on prompt reconstruction and chose to erect utility poles to run power transmission cables because it was a cheaper and faster alternative to burying them underground.
Today, there are more than 35 million utility poles across the country, and that number is increasing by roughly 70,000 each year as new roads are constructed. While major cities elsewhere in the world such as London and Paris have placed 100 percent of their power cables underground, the ratio stands at a mere 8 percent even in central Tokyo — where the effort to bury cables has made the most progress — and the nationwide average is much lower.
Efforts to remove utility poles because they are eyesores has been pursued in some areas since the 1980s. After the Great East Japan Earthquake and tsunami of March 2011 destroyed some 56,000 utility poles, legislation was enacted to facilitate the relocation of power lines underground, requiring the national government to take steps to expedite the effort and urging prefectures and municipalities to draw up plans of their own.
A panel of experts launched by the Ministry of Economy, Trade and Industry to review the slow restoration of electricity in Chiba will reportedly assess how effective burying power cables would be in preventing large-scale blackouts.
The biggest obstacle to burying power cables is the cost. The most frequently used method — digging deep trenches and running power and communication lines through them — costs about ¥530 million per kilometer, or 10 to 20 times the expense of erecting utility poles placing power cables overhead. The cost is shared by the parties that manage roads — the national government and municipalities — and the power companies and communications firms that run their lines through the trenches.
Efforts are afoot to reduce the cost by adopting smaller parts and changing the method of burying the cables, but even so it will remain massively expensive. Nonetheless, the removal of utility poles and the placement of power cables underground should be steadily pursued to prevent secondary damage from large-scale disasters.