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Electrical Upgrade Prescribed for Japan's Crimped Power Grid

Converter stations and HVDC transmission will accelerate renewable energy installation and challenge Japan's nuclear utilities

3 min read
Electrical Upgrade Prescribed for Japan's Crimped Power Grid

An advisory body for Japan’s powerful Ministry of Economy, Trade and Industry (METI) has endorsed a tripling of the capacity to pass power between Japan's otherwise estranged AC power grids: the 50-hertz AC grid that serves Tokyo and northeastern Japan, and the 60-hertz grid that serves western Japan. This frequency divide has complicated efforts to keep Japan powered since the March 2011 earthquake and tsunami -- a task that keeps getting harder with the inexorable decline in nuclear power generation (at present just one of Japan's 54 reactors is operating).

Bridging the AC grids is also seen as crucial to Japan's emerging post-Fukushima energy policy, which emphasizes reliance on wind, solar, and other renewable sources of electricity

METI's panel agreed that transmission operators should double Japan's east-west exchange capacity from the 1040 megawatts running currently to 2100 megawatts by 2020, according to the Tokyo-based Yomiuri Shimbun newspaper. This would require the addition or expansion of solid-state high-voltage direct current (HVDC) converter stations that break down AC power from one grid and synthesize a new waveform to pour it onto the other grid. It could also entail "beefing up" the transmission line feeding the converter stations, writes Yomiuri.

The panel also proposes government incentives to encourage the addition of another 1000 MW of exchange capacity, as well as additional HVDC transmission cables to expand renewable power exports from wind-rich Hokkaido in the northeast down to Japan's main island. 

While this week's proposal marks a dramatic increase from a 300-MW exchange bump proposed by industry officials in the wake of the Fukushima Dai-1 reactor meltdowns, the 2020 timing is far too slow according to some Japanese power experts. "The industry is still very conservative," is how an executive for a major Japanese power engineering firm responded to the proposal in an email exchange with Spectrum.

One intriguing note buried in the Yomiuri report states that the panel, "also agreed the government should play a larger role in building and maintaining power cable networks between different service areas." What sounds like a fairly tepid suggestion is potentially subversive when seen within the context of a debate raging in Japan today over the future of the ten regional utilities that hold an effective monopoly on power generation, transmission and distribution.

Japan’s Federation of Electric Power Companies, which represents the 'Big-10' utilities, says power industry reforms should promote competition and increase consumer choice, but keep generation, transmission, and distribution together. As federation chair Makoto Yagi put it in a February press conference in Tokyo, only the vertically-integrated utilities' “collective strength" can "ensure a stable electricity supply.”

Advocates of renewable energy see things differently, viewing the Big-10 as a barrier to the expanded grid interconnections required to share highly-variable renewable energy across wide areas. Those same interconnections inevitably weaken the hold of monopoly utilities by enabling competing power to enter their territory. 

What is clear is that the Big-10's hold on Tokyo is already weakening, making wholesale deregulation of the power sector look possible. "I haven't felt this optimistic about Japan for years," is how Andrew DeWit, an energy policy expert and utility critic at Rikkyo University, put it in my report this week for Technology Review magazine on Japan's renewables potential.

DeWit credits part of the deregulatory impulse to popular disgust with TEPCO, the utility that operated Fukushima Dai-1. But the bigger impulse, he says, comes from the government's premium-pricing scheme for renewable power that former Prime Minister Naoto Kan pushed through the Diet last year. The mandated prices, known as feed-in tariffs, are to become effective in July. "Maybe I'm just getting too little sleep due to deadlines," jokes DeWit, "but this approach looks to make deregulation palatable to interests, like farmers, who have always stood against deregulation because they had nothing to gain."

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