[marcosdumay]

> Many costs are absolute and _not_ marginal

If you turn off your gas generator and replace it with solar + batteries, you will spend the entire cost of solar + batteries plus the decommissioning cost of gas (that may be negative if you can sell some parts) to go back to exactly the same point you were before.

So, no the cost is only marginal if you accept you will follow the depreciation curve of you infrastructure. And that's way too slow to reach the goal.

[sokoloff]

We have some crazy incentives to install new gas boilers in MA. I very specifically wanted to switch from gas to an air source heat pump and found there was only one company in the area who was willing to quote it (alongside their own, much cheaper, quote for a gas combi boiler) and their quote was outrageously non-competitive with local fossil fuel burning (in large part because our electricity is around $0.30/kWh, but also because they were the only supplier and even they didn't really want to do the work).

Even if the ASHP lasted forever, required no maintenance ever, and you had to buy a new gas boiler every 10 years, it would literally never make economic sense even if there weren't $2500 incentives on the gas boiler, but the movement on electric rates is definitely in the wrong direction if one wishes to displace natural gas with electricity (even at 400% efficiency).

Every year that things stay like this is pushing back the likely time to next re-evaluation for that property by another 20 years.

[matthewdgreen]

The price of home solar and batteries is dropping to the point that $0.30/kWh is becoming untenable in any home that has a decent amount of roof space. You’re better off financing a rooftop solar plant and buying 3-4 days of storage, even if you remain tied to the grid. Insofar as those costs are being driven by generation, the declining price of solar should eventually place an upper bound on what people will pay for electricity. Even if you don’t live in a sunny place and even if net metering pays $0, with a few days of storage you can reduce your grid consumption to the point where your actual need to consume expensive electricity becomes a tiny fraction of your overall usage. I think this will tend to push costs downwards.

Even for people who don’t have the space or capital to install their own solar, this will happen writ large as the US builds out utility scale solar, wind and storage.

[sokoloff]

Unfortunately, we have a 100 year old slate roof, which makes solar some mix of difficult, expensive, or not advised. At the exact moment of maximum heat demand (both seasonally and time of day), solar generation is at its lowest.

I do hope that slate lookalike solar tiles become advisable and cost-effective as I’d be happy to pay a small premium to generate and store locally.

[matthewdgreen]

I sympathize. We can't install solar either because of roof pitch and trees. I think my overall point is that if many customers can install solar and bypass expensive generation, this will tend to put a downwards pressure on generation prices in the long term.

Solar aside, I am thinking about installing a battery system that time-shifts from low-rate times to high-rate times. It's almost cost effective now.

[gruez]

>So, no the cost is only marginal if you accept you will follow the depreciation curve of you infrastructure. And that's way too slow to reach the goal.

The linked article also mentions a way less aggressive timeline, which means there's less of "tear out existing equipment and replace with renewable" going on, which raises costs. Moreover, the argument isn't that there's no such costs, only that they're being overestimated.