[scope2093]

We installed roof solar (10kW panels + 8kW hybrid inverter + 32kWh battery + planning/execution) last October for 11k euro. After all the math, our "investment" would pay off in approx 8-10 years (at current electricity prices). That's without an electric car, which we plan to buy sometime in the next two years.

All in all, pretty happy. Especially that we have frequent grid faults. Even my ISP has some beefy batteries for their equipment, so much so that one 14-hour grid blackout didn't affect us at all and we were able to use the internet since we're working from home (FTTH + ONT, GPON).

Usual disclaimer, sample size of one. We're in Romania.

[jrmg]

Getting solar installed on our house, providing well over 100% of our energy needs overall (including car), has left me low-key kind of angry that we, as a society, are letting so much energy just uselessly fall onto structures and the ground when we could be harvesting and using it.

Especially in the US, and especially in homes, we tend to have dark roofs. Sunlight falls on these, heating the building up, then we burn fossil fuels to generate more energy to pump the heat outside. It’s absurd.

[scope2093]

I agree. The momentum seems to be building up though, at least in (east) Europe, so there is a glimpse of hope.

Fun fact: we still don't have AC in our house (it's a new-ish building, built 4 years ago) because it's decently insulated (and we live near the mountains). As in your case, our solar produces way over 100% of what we need, so I'm considering just getting AC to use the sun to cool the house if needed :)

[DanielHB]

I live in Sweden and there is very heavy insulation, however it makes it unbearable at the end of the summer days (sunset around midnight). I am lucky my current place the bedrooms get the morning sun, not the afternoon sun like my old place.

In my old place I would often sleep in the living room sofa because of the heat.

[scope2093]

Our place is more like your old place: all the bedrooms get the afternoon sun. We usually relied on having the blinders (external ones, electrically actuated) down, keeping the bedrooms dark until sunset (and using the external cool air at 7AM to cool the house for ~1.5 hours). It still doesn't solve the issue completely, the interior air temperature sometimes gets to 29-30 Celsius in the afternoon.

A bit on the toasty side. That was before we had solar installed, now we might as well get AC to use the sun to our advantage. On a personal note, I like the interior a bit warmer, somewhere around 24-25 Celsius.

[dzhiurgis]

Does your windows have IR film?

[pstuart]

Air conditioning is a substantial load on the grid and those that need it most are likely better suited to solar (more sun to heat, more sun to generate electricity). As you noted, it pays for itself and then is "free".

In a different timeline, we'd be investing in the country via zero/low-interest loans to encourage every homeowner to leverage this. It's a win for everybody.

[ragebol]

On X/Twitter, I'm sometimes seeing graphs comparing energy usage per capita in the US vs the EU and China, with the narrative that the US is 'better' in some way because the higher energy usage.

And then there is stuff like the above indeed, uselessly wasting energy while things could be so much more efficient.

[HerbManic]

For years, maybe 20 now, I have seen a few people that seem reputable in terms of their positions and data they project that says that we should not have as many solar panels as we do. It is restrictions on rare materials etc. Some of them are probably paid to have this position, others seem genuine.

And yet, look at what is happening. Year after year the exponential growth continues without a blip! It is one of those things that looked impossible initially but obvious in retrospect.

My broader long term fear is that if we essentially get "limitless" energy, we continue to harm the ecosystem in other ways. Like giving a drug addict a limitless bank account. But we are still a long way from that point.

[DanielHB]

Limitless energy would likely bring more ecological gains in other areas. For example vertical indoor farming with artificial lights. If energy was free it is vertical farming would be massively cheaper than it is today.

Vertical indoor farming is far more sustainable than outdoors farming.

It would also push electrifying other types of transportation that is harder to electrify like airplanes and ships. For example, if energy is free flights in smaller electric planes with more connections would be far cheaper than getting direct flights in jets.

Free energy also means cheaper recycling, currently aluminium scrap gets shipped around the world to places that have cheap energy (like iceland with geothermal power) for recycling. With free energy you would be able to do it locally.

[roryirvine]

For the next decade, we should concentrate on building out grid-scale storage to soak up the surplus energy available when the sun is shining and the wind is blowing. Green hydrogen is the likely the next best use, as it will in turn enable things like direct reduction of steel.

If we get to the point where we can reliably expect 8-12 hours of free electricity 80% of the time, then things like Direct Air Capture of carbon become viable - but that's likely 25-30 years off, so who knows what other technologies will have appeared in the meantime.

[imtringued]

>Vertical indoor farming is far more sustainable than outdoors farming.

It's not. "Vertical indoor farming" is heavily biomass constrained and this won't change even with infinite energy.

Have you ever paid attention to the types of crops grown in vertical farms? "Leafy greens" is a phrase that is used almost exclusively in the context of vertical farms and nowhere else. Most people talk about the specific vegetables they've had in their salad, not a broad category of vegetables that can be used for salads.

"Leafy greens" are "interesting", because they have an incredibly high water content, meaning less biomass is needed to produce the same volume of produce and they tend to have small root networks, which means that most of the biomass is edible and can be sold. They also tend to be small in the vertical direction, which allows more vertical stacking.

[agumonkey]

this is indeed a flaw in modern societies, we get lost in technological "progress" and become blind and dumb

[porphyra]

Nice. In the US, it cost us $35k to install 7.6 kW panels + 13 kWh battery. But our PG&E electricity prices in the Bay Area are also several times more expensive than in Europe ($0.50 per kWh) so it will also pay off in 8-10 years.

[scope2093]

$35k and $0.50 per kWh is quite pricy. My brother is in US (Kansas) and he told me that for the time being, it doesn't make sense for him to get solar, as the utility price is something like $0.07/kWh and he uses a low amount of electricity and install cost would be somewhere around $20k-25k. I think the math works?

We also did the math for ourselves with 8-10 years at current electricity prices: 30 eurocents/kWh (which got 3x more expensive in the last 10 years). So we might be lucky and break even even sooner.

[codazoda]

Plus $15k to move them for new shingles when the time comes, if they’re on shingles.

I wonder why we don’t use them to build shade structures instead.

[reustle]

Curious, when you calculate 8-10yr payoff, are you taking into account the last 10-20 year kwh cost inflation trend as well?

[YWall39]

!35K, I just payed $11K for the same in Europe. But here in Spain it is not financially worth it, but insurers against frequent brownouts and 3 outages a year

[sandos]

11k euro is INSANELY cheap?

Afaik there is absolutely no way to the same thing legally here in Sweden. Unless prices have really fallen off a cliff.

[scope2093]

Yes, indeed, once I saw the math/price, it seemed like a no-brainer to just install it. Anedoctal, of course, the rumour is a few (small-ish) companies here offer their complete services abroad in EU (at least to Germany to my knowledge), which makes it very cheap to install, but I did not interact with said companies.

I have friends in Germany and their solar (similar to ours, no batteries) installation cost more than double. At the time, it seemed expensive and out of reach...

EDIT: forgot to mention that there is a big solar installation boom here, our godfather has a small company which just installed two solar parks and waits for them to go into operation (which is harder than it sounds, due to bureaucracy).

EDIT 2: Just for fun, I've calculated todays price (retail price at the time of writing this) using Romanian prices:

- 22 solar panels (460w): 434.39 RON/panel [1]

- 8kW hybrid inverter: 4873 RON [2]

- 2 16kWh batteries: 17576 RON [3]

Total is 32009 RON, that is (at current exchange rate) 6088EUR. The rest is service (planning/execution), warranty and so on.

[1]: https://depozitsolar.ro/canadian-solar-4/canadian-solar-toph...

[2]: https://ecobatenergy.ro/invertor-deye-hibrid-sun-8k-sg05lp1-...

[3]: https://ecobatenergy.ro/acumulator-renon-lifepo4-xcellent-pl...

[dzhiurgis]

Missing gst.

[scope2093]

My bad, indeed, for the inverter and for the batteries I missed the gst. I still believe it's good value, even with the added tax.