RetireJapan

Just wondering if anyone has an opinion on the financial viability of solar power in Japan these days?

It's actually for my place of work as we'd like to become a little greener but of course not lose out financially.

I came across Trende https://trende-eng.com/en/trendejp-2/ which is an interesting option as they have no upfront costs or running costs, you basically allow them to fit panels on your roof and then get a small decrease in your electricity bills.

Any insight would be welcome.

I installed panels just over a year ago, in the first full year our electricity bill was basically zero from a combination of generating our own usage and selling excess. I calculate payback of 8 years or less.
Something to consider though is the price will currently get from selling excess will drop drastically within 10 years. At that point we may consider battery storage.

Don't know about Trende, I parted with hard cash

Jake wrote: ↑Wed Mar 31, 2021 5:03 am I installed panels just over a year ago, in the first full year our electricity bill was basically zero from a combination of generating our own usage and selling excess. I calculate payback of 8 years or less.
Something to consider though is the price will currently get from selling excess will drop drastically within 10 years. At that point we may consider battery storage.

Don't know about Trende, I parted with hard cash

Thanks Jake, good to know. How does the battery storage work exactly? You save the energy you generate to a battery then use it to power your house?

ExpatScot wrote: ↑Wed Mar 31, 2021 10:55 am Thanks Jake, good to know. How does the battery storage work exactly? You save the energy you generate to a battery then use it to power your house?

Yep, that's one method that is popular after people's feed-in tariff period comes to an end. Another method that can be profitable even during the feed-in tariff period is to charge the battery overnight using grid electricity bought at off-peak rates, then use this electricity for your own use during the day. This maximizes the amount of your solar energy you can sell to the grid at the higher feed-in tariff rate.

ExpatScot wrote: ↑Wed Mar 31, 2021 10:55 am
Thanks Jake, good to know. How does the battery storage work exactly? You save the energy you generate to a battery then use it to power your house?

Basically yes. During the daytime we (usually) produce more than we use so the excess goes to the grid at a fixed cost, as I type currently using 1kW and selling 4.8kW. At night of course we buy some back.
Adding a battery pack would mean hopefully eliminating the night time buying.
Unfortunately the difference in buying/selling cost currently isn't enough to justify the extra investment of the storage, even the sales guy said that. But as battery technology improves and costs come down it should be more viable.

Batteries will be important in the future, but I think they are still too expensive to be viable. Given how much research is going into them though, I am hoping that will change. If they were about half the current price, I would be tempted to get one for our manshon mainly for keeping the electricity on after natural disasters

RetireJapan wrote: ↑Thu Apr 01, 2021 8:59 am Batteries will be important in the future, but I think they are still too expensive to be viable. Given how much research is going into them though, I am hoping that will change. If they were about half the current price, I would be tempted to get one for our manshon mainly for keeping the electricity on after natural disasters

There are scenarios available today which will make purchasing a battery attractive for some, e.g. as part of a house-builder promotion (e.g. Ichijo), and if the local municipality offers a large grant. I wouldn't want people to rule the option out straight away upon reading this thread, but I think you're right that it will not make sense for most people for a few years yet.

And there is a lot to be said for having one now ready for the blackout that will occur when Fuji-san next erupts

RetireJapan wrote: ↑Thu Apr 01, 2021 8:59 am If they were about half the current price, I would be tempted to get one for our manshon mainly for keeping the electricity on after natural disasters

Maybe, but in my experience I lost power for 24 hours after the Tohoku mega shake, and probably the same after the typhoon that ripped through Chiba 2 years ago so haven't lost much. Of course other people I know lost power for a week or more....

One thing I do have with my system is a couple of power outlets which will work directly of the solar panels... in the daytime of course
This means I can connect my freezer to save my food, charge some devices or battery packs etc.

Aren't some EVs usable as a backup battery?

The Nissan Leaf can be used to connect to your home for power during a outage. You gotto install a vehicle 2 home (v2h) to get it working though. There is a cheaper option where the car battery will be connected to only one of the outlet and a more expensive option where the car battery can be used in all outlets inside your home.

There is government subsidy starting up soon with EV cars and the V2H system. I am interested in it myself since I already have solar panels. The cost of the storage battery and their lifespan just doesn't seem worth it at this time.

https://blog.evsmart.net/ev-news/2021-e ... idy-japan/ Here is the link to the government subsidy information.