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Three years ago, just before the great Tohoku Earthquake and disaster, we connected our solar inverter to the grid. It is still noisy, but for power the system does perform. If all years are as good as this third  year, when we sold 2702 kWh and consumed the rest, we will reach payback break-even after 11 years, not in 13 years as we initially expected, based on the installer's forecast of harvesting 3477 kWh a year. After that it is all profits for as long as the sun shines, the system works, and TEPCO buys the electricity.

On 2014-02-28, our inverter showeds 13567 kWh harvested, of which roughly

  • 1/3 is own consumption, for which we do not need to pay on average 28 ¥/kWh, daytime rate with "8-Hour Night Service"
  • 2/3 feed into the grid, most near peak time, reimbursed at the subsidized rate of 48 ¥/kWh

For reference: TEPCO electricity rates in English

So, how is life with solar?