this post was submitted on 20 May 2025
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First image is of an overcast sky with a guy with two nearly-vertical solar panels
Third image is of a small solar panel under a roof receiving a little bit of light at an extreme angle through an opening in a covered attic balcony
Here's a solar farm in the US:
https://www.energy-storage.news/wp-content/uploads/2024/08/de-shaw-1024x731.jpg
It's pulling a lot more power per panel.
Another:
https://www.fhwa.dot.gov/ipd/images/project_profiles/img_az_navajo_nation_kayenta_solar_program.jpg
Another:
https://cdn.orsted.com/-/media/feature/vocastimport/orsted_permianenergycenter_cod_0398_698890436958977.png?mh=1440
Does it make sense to stick solar panels on a house relative to drawing power from a solar farm? Sure, it can, if your house is remote and it's costly to connect it to the grid, or if what you're after is a secondary, backup source of power if you lose grid connectivity.
But if what you want is cost-effective generation, it's preferable to stick a panel on a solar farm somewhere where one can leverage economies of scale, maintenance is easy and done by someone who maintains a ton of these on a regular basis, and where you're optimizing location and panel orientation for solar potential.
Like, if you want more solar power on the European grid, you probably want more solar farms in Spain, which has substantially more solar potential than Germany:
https://globalsolaratlas.info/
Not someone sticking them on their balcony in Germany.
What Germany could do to help solar and wind, if it wants to do so, is drop complaints about building (inexpensive) above-ground transmission pylons, which would help smooth out different generation at different locations on the European grid.
https://www.cleanenergywire.org/news/farmers-and-grid-operators-demand-end-rules-prioritising-underground-power-lines-germany
EDIT: If you want to criticize the US for something as solar goes, it'd probably be Trump throwing tariffs on everything, which makes it more costly to deploy solar panels and other electrical hardware manufactured abroad.
The biggest advantage of balcony-mounted solar panels, at least where I live, is that you need 0 permits. You don't need to ask your neighbors, you don't need to ask your power company, you don't need a building permit, you don't need an electrician and you don't need a solar company to install them for you.
They don't replace large solar farms but if you incentivize people to DIY their solar installation you get tons of additional cheap and clean energy from a source that would be wasted otherwise.
What are you powering with it? How are you storing the energy? It just doesn't make any economic sense to me. I'd love to see some statistics on the total cost of one of these systems and how much power people are actually getting. Maybe it makes more sense in Germany where energy prices are nearly double the US average. But I'd still love to see some real examples to back that up.
Balcony solar panels are dirt cheap, you can get them for 200-300€, including the micro inverter. You usually do not have batteries in these setups, you just use up the generated power while it is available by moving things like the dishwasher and dryer to that time.
To give some actual numbers, I pay 0.22€ per kWh right now. In the last 30 days (Apr 21 - May 20) the balcony solar panels generated 74.11kWh. The month was fairly average with an even mixture of sunny days and rainy days.
Assuming you can use up the 800W of peak power, you will have saved around 16€ in just those 30 days. I don't have full data for the year yet since I only got mine a few months back but my current estimation is that it will have paid for itself after 2-4 years.
How are you getting power to your appliances? Someone else suggested back feeding into an outlet which is illegal in the US.
Back feeding is legal here if it is connected to a micro inverter which can turn off immediately when disconnected and never outputs more than 800W.
And this is the answer to why it makes sense in Europe and not the US.
You plug it straight into the wall, it syncs to the grid and back-feeds it, up to 800W. Your meter stops spinning (or even goes backwards)
Back feeding is illegal in the US.
I think you're comparing apples to oranges.
The main selling point for a "Balkonkraftwerk" is that it's cheap and doesn't require an electrician to install.
That way they pay off rather quickly and result in a lower electricity bill when you look at a span of 10-15 Years.
Solar farms in Spain on the other hand require massive investments in Infrastructure and the farms themselves. Not to say they're a bad idea, but it's a very different thing.
In the US, a lot of problems have arisen around residential solar installation companies providing loans using questionable, if not outright fraudulent sales tactics based around misrepresenting returns.
https://time.com/6565415/rooftop-solar-industry-collapse/
Companies running solar farms, on the other hand, have bean-counters in place who are in a legitimate position to run the numbers, and those companies take on the risk themselves. With residential solar, it's not companies saying "hey, we'll put our capital on the line, and just want somewhere to put a panel", it's "here's a graph and some numbers, and there's a great investment opportunity for you with your capital...just sign on the line here!" Needless to say, this opens the door to a lot of potential unpleasantness.
EDIT: If a company sends a guy to your doorstep to tell you how they have a fantastic investment opportunity for you and your money which will make you a great return, a good response is to ask them why they don't want to make the investment themselves. Is it generosity on their part, letting you enjoy the benefit of the investment?
If a solar panel installer wants to put panels on a roof I own, that's fine with me. All they have to do is pay me for the space on my roof and cover the cost of the hardware and its installation. In return, I will let them have the entire value of the generation done, rather than taking it myself. If this is a legitimate investment with a valid return for the party putting money down, then they should be happy to do that.
One notices that there are no residential solar installer companies who are engaging in that sort of arrangement. Cell tower companies do that with cell infrastructure, but not residential solar installers. Hmmm.
The whole argument is that you need neither a loan or a professional installer for a Balkonkraftwerk. Your're completely missing the point.
While I agree with your sentiment, I'm not sure the cell tower is a good comparison. Very few if any cell towers are installed on a residential single family roof. Leasing part of your plot of land or space on a commercial or multi unit building is a completely different problem than giving a company rights to part of a frame residential home. Who maintains the roof? Who insures the roof? What insurance company will write that policy? It's already getting more complicated to insure rooftop solar because claims are climbing. Now you've got a roof leased to someone else with solar panels on it? Seems to me like any commercial venture would skip all that and go straight to buying or leasing land. Land with no homes. This is the US after all, we have plenty of that laying around.
Companies are offering rooftop solar owned by the residents because they want it, they want the benefits. The problem is that it's rapidly growing and a great target for scams. Especially considering the age demographic of homeowners who have paid off enough of their mortgage that they have collateral for said loans. These companies should be regulated and vetted somehow.
There is a benefit to putting solar close to the load. Less transmission losses/upkeep.
There is a benefit to putting solar on roofs/buildings... Less environmental impact.
https://www.eia.gov/tools/faqs/faq.php?id=105&t=3
As per the globalsolaratlas map I linked above, you have on the order of 50% more solar potential in Spain than Germany. And that's before one considers alignment, shade from surrounding structures and vegetation, and similar factors that affect sticking panels on a house, which favor solar farms.
I love how you address only 1/3 of the items I brought up!
I have 0% loss on my house (except for the inverter losses, which the solar farms would incur as well). With 0 trees blocking anything.
Upkeeping massive transmission lines isn't free. Adapting solar to the current grid also isn't free and lossless. Transformers on the road to bring down voltage are a 1-2% loss on their own.
Massive fields of solar has upkeep/environmental costs as well.
If you choose to misconstrue me bringing up valid points as to why we should also be installing solar on buildings as an argument to never install solar farms... that's up to you. But there is value to putting production as close to load as possible.
You brought up losses and environmental impact. I addressed only losses.
Okay. "Environmental impact" is hard to quantify, but you could try and put a dollar figure on the cost of putting a solar panel in the desert. You should already be internalizing any costs, though, and that's not where companies are choosing to stick solar farms.
Sure. It's just that having solar panels on balconies relative to solar farms in a desert is outweighed by the drawbacks, if your goal is cost-efficient generation (which as I pointed out in my original post, isn't always the primary concern).
I brought up losses, upkeep, AND environmental impact.
All three of these items affect the cost of generation that you're ignoring.