What a year of solar and batteries saved us in 2025 • Hacker News Board

Re: What a year of solar and batteries saved us in 2025

#361

Post by dlcarrier » Wed, Jan 14, 2026, 5:58 PM UTC

coryrc wrote: post #232

dlcarrier wrote: post #67

Where I am in California, there's a $30+/mo charge to connect to the grid, and the largest savings from a battery was being able to disconnect from the grid. There's lots of time I have excess power generation when I could give to the power grid, if I were connected, but I would have to pay extra to do so, so the potential goes unused.

Unfortunately no urban places allow you to remove from the grid.

California doesn't require households to get power service, but pretty much everywhere where trash service is available, it's required.

Re: What a year of solar and batteries saved us in 2025

#362

Post by mbesto » Wed, Jan 14, 2026, 7:56 PM UTC

pchew wrote: post #352

mbesto wrote: post #351

Earlier quoted context omitted.

You keep throwing out specifications without understanding their real life installation use cases and then go as far as to make claims like "EG4 support is bad for DIY'r" which is so far from the truth it's hard to take anything you say seriously. There are hundreds of thousands of forums and YouTube videos from DIY who rave about EG4. In fact Sol-ark has a sketchy support track record (source - several installers I…

>You keep throwing out specifications... >And for the last time... Well, neither of these are relevant to my original comment. I never commented on the value prop of the original install, only that your comparison in pricing is just not accurate as one is much more capable. Yes, lots of people want 34kw of standing load, because they want to ensure the offset of their HVAC unit. Generally people getting these systems…

> Yes, lots of people want 34kw of standing load, because they want to ensure the offset of their HVAC unit.

The author of the post lives in the UK and averages 2kW load, a 4 kW PV system, and 45 kWh battery system. It's literally impossible for them to run a standing load of 34 kW for more than 1.5hrs without a grid tie. Why do you keep ignoring this?

Re: What a year of solar and batteries saved us in 2025

#363

Post by themeiguoren » Thu, Jan 15, 2026, 12:10 AM UTC

NoLinkToMe wrote: post #343

UltraSane wrote: post #68

Earlier quoted context omitted.

That is still an enormous amount of electricity for a single family to consume.

Sorta, kinda, it depends. In my house I only run LED lighting and an occasional oven, some phones and laptops, a cycling fridge and two weekly wash cycles, in other words, virtually no electricity. I'm at like 2 kWh per day. The ~45 kWh a day for this family is gigantic compared to mine, like >20 of my homes in one. But I don't have an electric car, nor electric heating or cooling, nor an electric stove. If you have…

I ran my power bill for a small single family home through chatGPT and it was interesting. Cold winters/hot summers, electric stove, air conditioning during summers, and nothing else out of the ordinary that uses power.

- Base electricity: 17 kWh/day (10 in months without AC)

- Heating (currently gas): 33 kWh/day

- Heating (if I switched to heat pump with COP 3): 10 kWh/day

- EV charging at 10k miles/yr: 9 kWh/day

Total if I was fully electrified: 36 kWh/day, or 13 MWh/yr

Re: What a year of solar and batteries saved us in 2025

#364

Post by culebron21 » Thu, Jan 15, 2026, 7:05 AM UTC

coryrc wrote: post #227

culebron21 wrote: post #226

How does a household use 1,500+ kWh per month? At my home, we sometimes get above 200, in summer with AC we may score 300 kWh, but how do you consume 5x of that? Is it heating?

Is your heating electric and do you have two electric cars?

No, we either walk or use public transit, and we have central heating. Yes, this explains the difference.

Re: What a year of solar and batteries saved us in 2025

#365

Post by specialist » Thu, Jan 15, 2026, 4:54 PM UTC

toomuchtodo wrote: post #47

boringg wrote: post #34

9-11 year payback isn't bad based on the projections. You could probably goose it a bit with inflation of electrical prices (depends on how the electrical policies change and what they pass through). I'll also add theres some O&M coming down the line. Inverters @ year 10, small maintenance and Im assuming you re-did your roof before you installed. Anyone putting solar up make sure you do it at the same time as a roof…

It is essentially a bond return, with the caveat being that solar PV panels will last 25+ years with some degradation and reduction in output. To your point, the best arrangement (imho) is a standing seam metal roof (40-70 year lifetime) with the panels mounted via friction racking with no roof deck penetrations. This avoids the economic cost of pulling everything off the roof to re-roof, and should outlive any homeo…

> essentially a bond return

You reminded me: David Roberts' often states that a hurdle for electrification and decarbonization projects is connecting them to "slow capital". Stuff like residential, community, solar, battery, heat pumps, appliances, ground source heat, yadda yadda.

I gather that there's plenty of "slow capital" perfectly happy with low risk long term modest returns. But these projects are too small to be worth the effort. Probably something about transaction costs.

My impression is there's an opportunity to bundle up these projects for the larger/largest investors. Biden's IRA created a "green bank" (RIP); maybe that was its intended function.

You're smart about money and finance, so you can probably explain what Roberts is talking about (to noobs like me).

https://volts.wtf

Re: What a year of solar and batteries saved us in 2025

#366

Post by toomuchtodo » Thu, Jan 15, 2026, 6:08 PM UTC

specialist wrote: post #365

toomuchtodo wrote: post #47

Earlier quoted context omitted.

It is essentially a bond return, with the caveat being that solar PV panels will last 25+ years with some degradation and reduction in output. To your point, the best arrangement (imho) is a standing seam metal roof (40-70 year lifetime) with the panels mounted via friction racking with no roof deck penetrations. This avoids the economic cost of pulling everything off the roof to re-roof, and should outlive any homeo…

> essentially a bond return You reminded me: David Roberts' often states that a hurdle for electrification and decarbonization projects is connecting them to "slow capital". Stuff like residential, community, solar, battery, heat pumps, appliances, ground source heat, yadda yadda. I gather that there's plenty of "slow capital" perfectly happy with low risk long term modest returns. But these projects are too small to…

Stay tuned, I have an idea to soak up global capital for these projects.

Re: What a year of solar and batteries saved us in 2025

#367

Post by vagab0nd » Sat, Jan 17, 2026, 3:42 PM UTC

modeless wrote: post #225

mbesto wrote: post #52

It's wild how overpriced Tesla Powerwalls are. 16 kWh battery with all of the UL supported listings etc = $3300 [0] 13.5 kWh Tesla Powerwall is $12k~$15k You would get your return way back quicker. [0] - https://www.ruixubattery.com/product-page/lithi2-16-battery-... EDIT: As others have pointed out, powerwalls have inverters built in so it's not totally apples to apples. You can get a beefy inverter for $5k and it's…

The crazy thing is you can buy a 69 kWh battery from Tesla for $36,990, and it comes with a whole car too.

Exactly! This is how the future should be: solar panels + portable huge battery arrays doubled as vehicles + grid as backup.

Re: What a year of solar and batteries saved us in 2025

#368

Post by snapplebobapple » Sun, Jan 18, 2026, 1:44 PM UTC

greycol wrote: post #222

jillesvangurp wrote: post #165

Earlier quoted context omitted.

There's going to be a bloodbath in that market in the next years. There are a lot of battery producers and most of them are not producing at full capacity. At the same time, manufacturing cost is dropping as well. Some battery makers are producing batteries at a cost level of around 60$ per kwh. At that cost, the 16kwh battery would come out below 1000$ (not the same obviously as the product price). Sodium ion might…

One thing to remember is as it becomes more widespread line costs will go up (assuming they are subsidized by kwh use, which they generally are) and no-sun power prices will increase as it's the only time when the grid needs power from non solar producers and they still need to cover cost incurred while they're not producing. That will push the economics towards completely off grid systems as more people adopt solar,…

Many cities in north america you cant get occupancy without grid tied electricity, so every house incurs the coat of bas government policies on transmission. Its why i havent bothered with this yet. The optimal setup for here is natural gas generator, some battery and some solar given how stupid the fixed charges are here but you cant live in your house if you disconnect from the grid (even better would be for fuel cell manufacturers to offer something sized for a house so i can get hot water put of it as well and a silent unit)