How much ‘easy PV’ could Japan build?

Renewables International

In 2012, Japan introduced a feed-in tariff for solar power, with the goal of kick-starting its relatively dormant PV market. So far the policy appears to be succeeding, and Japan is experiencing the onset of a solar boom. This opens the door for inspirational questions like: How much “easy PV” could be installed?

“Easy PV” is solar power that can be integrated into the grid without leading to “negative” residual load. For the sake of the “easy PV” argument, we’ll ignore that Japan is home to the wordls largest existing grid-level storage capacity in the form of 25 GW of pumped hydro.

High peak summer demand

Japan is a great nation for solar power. It has more sunshine than Germany (that’s an easy one, I admit), it has densely packed urban areas and a domestic solar industry with a very long tradition. Most importantly, its electricity demand usually peaks during the summer around noon. The Japanese record for peak summer demand occurred on July 24th 2001; it stands at 182.7 GW.

Such extremely high levels are, however, very rare. The Japanese Federation of Electric Power Companies says that today’s peak demand is reached a “mere” 147.5 GW, more than twice the average German peak summer demand of 65-70 GW.

Huge “easy PV” potential

So let us assume that we want solar to peak at maximum of 120 GW, leaving a comfortable margin for hydro & other must-run-units and making it relatively easy to integrate PV into the grid.

Experience in Germany has shown that even on very sunny days the cumulated PV output peaks at approx. 70% of the installed capacity because PV systems face the sun in different angles and have different insolation conditions across the country. Japan could then install about 170 GW of PV.

In a relatively sunny country like Japan a PV capacity of 170 GW would produce at least approx. 180-200 TWh of electricity every year, enough to supply approx. 20% of Japans electricity mix with secure domestic renewable energy.

That would be quite a big chunk and in many ways a far better choice than relying on imported fuel oil and LNG to generate 60% of the nation’s electricity (40% before the nuclear crisis began).

Source: Renewables International. Reproduced with permission.