Tokyo makes solar panels mandatory for new homes built after 2025 | Hacker News Reader

Tokyo makes solar panels mandatory for new homes built after 2025

reuters.com

54 pointsDamonHD22 comments

It makes a lot of sense. Solar panels are getting affordable now. I see so many houses built hot climates that always makes me wonder how much energy these houses can harvest if all of them had solar panels on them.

And indeed would benefit from having sun kept from their roofs, helping the houses stay cool in summer...

But making them harder to heat in winter.

Is that a problem if a majority of the energy for heating is renewable?

How so?

I have solar PV on my roof and it makes no direct difference to the heating required. Except that I have a little generated energy that provides some warming inside from the appliances that it powers.

If solar panels block the sun from heating the roof in Summer (making it easier to cool) then the reverse is true in Winter. Some amount of free energy is no longer hitting the roof and potentially changing the energy equation.

Is it a meaningful difference, I am not sure. However, it is only fair to count the impact on both seasons. Heating costs are significantly higher than cooling (larger absolute temperate delta required to go from 30f to 70f than 90f to 70f)

There is no meaningful solar heat transmitted in through the roof in winter, at least in a climate and building like mine, which is fairly typical.

The whole world needs this. Especially with the absolutely terrifying North Carolina incident.

Green energy is no longer just about the green, we need decentralization to protect against people who don't want us to have electricity at all.

When we finally move on from lithium, maybe they'll start requiring battery backups too.

What "North Carolina incident" are you referring to?

https://en.m.wikipedia.org/wiki/Moore_County_substation_atta...

Thanks for the clarification. I've been out of the country for a week, and that was an alarming sentence to read while waiting to board a Charlotte-bound flight!

Not against the rules but as an interesting data point, somehow Australia has just about archived this with no mandates. I’d say about 80% of buildings, commercial and residential have solar installed.

There have been financial incentives from the government though.

The financial incentives drove this, 100%.

As an Australian, with solar panels, and a not-too-terrible feed in tariff, I'm hoping we can cram more energy production in to less space from solar so that I can upgrade my system in the decade to come, hopefully to match the hybrid I'd like to buy that doesn't yet exist :)

Hopefully by then all the hybrids will have ultrathin panels on the roof and you might not even need as much fixed solar!

How decentralised exactly solar energy source is when manufacturing is 95% depndent on China?

It might not decentralize economic power but it decentralizes how many places a terrorist needs to hit to take down the grid, which is the big reliability concern.

Plus, even if the supply chain went away we'd have decades to build plants before existing panels became unusable.

It's a problem not to have our own panel factories, but that's a problem we can fix.

Technically so is protecting substations, but it doesn't seem like there's that much interest in it, nor is there much research on hardening against another Carrington event.

"Decentralization" that is needed because of unstable energy prices caused by pathological politics and green ideology fail itself if offer solution from China.

While I agree with decentralization, definitely not because of "terrorism", but because of government "regulations". Lobby is strong and usually not in favor of citizens. Current situation in EU with energy prices is model example, how centralized supply of energy is weak. Water will be next.

But please... No dependency on totalitarian China.

Hamburg too from 2023 and for roof replacements from 2025 for all buildings.

https://www.hamburg.de/energielotsen/beratung/15147914/faqs-...

This is an even more effective strategy given the Japanese culture of constantly rebuilding housing [1]. It does beg the question of how sustainable that practice itself weighed against the benefits of solar installation.

[1] https://www.theguardian.com/cities/2017/nov/16/japan-reusabl...

This is by far the most popular link that I have posted to my mastodon.energy account! Don't know why! (And yes, I have lobbied my local council here in London to mandate similar...)

China communist gonverment appreciate it.

That makes comrades in CCCP happy. 95% solar panel production is made in China.

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