[iso1210]

This does work today at grid scale, people use their home batteries (either on wheels or not) to charge/discharge to the grid in the UK all the time.

If someone builds that storage facility to do it commercially then great.

> rooftop solar can't exist without special subsidies

Yet it does

[mercutio2]

I think you may have missed the point here.

Rooftop solar is heavily subsidized almost everywhere it’s popular. Rooftop solar isn’t a good deal for utilities or their non-rooftop-solar customers.

I say this as someone who lived off the grid on solar for years; encouraging rooftop solar may have kickstarted the learning curve for the solar panel industry, and as such may have been pretty good social policy.

But it definitely owes its existence to subsidies.

These days grid scale solar makes lots of sense, rooftop solar still doesn’t (and the subsidies are now harder to defend).

[sokoloff]

There are special subsidies for rooftop solar here in the US (Solar Investment Tax Credit). Are there not subsidies for solar where you live?

https://www.seia.org/initiatives/solar-investment-tax-credit...

> The solar Investment Tax Credit (ITC) is one of the most important federal policy mechanisms to support the growth of solar energy in the United States. Since the ITC was enacted in 2006, the U.S. solar industry has grown by more than 200x - creating hundreds of thousands of jobs and investing billions of dollars in the U.S. economy in the process.

[philipkglass]

The same link says:

The Section 48 commercial credit can be applied to both customer-sited commercial solar systems and large-scale utility solar farms. The rate is effectively at 30% until Treasury issues guidance on new wage and apprenticeship standards. Two months later, the rate will be at 6%, with an additional 24% (for a total of 30%) available for meeting these new labor standards.

So utility-scale solar farms can get the same 30% credit as rooftop solar. They're both tax-advantaged compared to (e.g.) building a new gas plant, but the rooftop credit isn't any higher, at least not on the federal level. Self-consumption from rooftop solar may avoid other taxes, like sales tax, but in many states there is no sales tax on residential electricity to begin with.

[sokoloff]

The interesting question of there being a subsidy for rooftop solar is the difference in subsidy to me between my roof having solar panels or my roof not having solar panels, not between my subsidy for my roof having solar panels or someone else's for their field having solar panels on it.

[fwungy]

Subsidies are a terrible way to run energy policy because they can change quickly with politics. Big players stay away from big commitments to subsidy based markets.

[sokoloff]

Subsidies of “do this this year and we’ll pay you $X” work and are relied upon. Subsidies like the CF that was the SREC market are indeed highly suspect and should not be relied upon, as generators of SRECs can attest.

[iso1210]

Not any more, other than no sales tax on the panels.

[sokoloff]

??

It's part of the "Inflation Reduction Act of 2022" (and at a higher rate than before): https://www.solar.com/learn/inflation-reduction-act/

[iso1210]

That's a foreign law applying to a foreign country