There's a funny comment downthread that says "It's like the backyard furnaces during the Great Leap Forward."
Everyone replying disagrees, but I think it's a perfect analogy: just like the backyard furnaces, these small-scale installations are inefficient, provide a negligible portion of total energy needs (<1% of total energy needs if everyone in Germany did it, from TFA), look ugly and - this is the most important - provide the feeling of doing something about a serious problem without actually doing anything substantial.
Actually, it is pretty common for homeowners to first install a balcony solar power plant and eventually "upgrading" to a full-scale solar power installation on the roof. The first is very easy and cheap to do and can be done on a weekend, the latter is costly, requires dealing with bureaucracy and partially-sleazy system sellers, and thus requires overcoming way more substantial hurdles, for which one must muster the motivation first.
Balcony solar power plants are sort of a gateway drug into actual, practical participation in the renewable energy sector. They are easy to install, cheap, have a clear and fast way to profitability, and provide significant gamification value (people who buy these kits tend to start with constantly monitoring their energy generation and usage in apps afterwards). That "ice breaker" effect should not be underestimated. It can pave the way to way more substantial actions (or to the acceptance of actions taken by others) that people wouldn't have considered otherwise simply due to inertia of the status quo.
> look ugly
That is YOUR taste. I consider most balconies with solar panels to look futuristic and cool. Garden houses with solar panels on the roof also look way cooler and more modern than without them.
And yes, 1% of German energy is a ton of energy; but that is an incredibly optimistic forecast of if _every_ German did this. There are 85 million Germans; they could do a lot of things with their combined efforts. Backyard furnaces produced millions of tons of steel; seems like a very apt comparison.
I actually have solar of my own. It powered my entire life (off grid!) for years. That still doesn't mean I think individual small-scale solar is a meaningful solution to the climate crisis.
The biggest risk around climate, in my opinion, is the risk that people and governments think "we're doing something" when they are not. In this case, balcony solar has a very short payback time (a claimed 5 years for one guy's install! That is preposterously short for any investment!) because of the strange way that residential power is priced. If people really paid for the power and the grid infrastructure in relation to the real costs, balcony solar would never pay itself back, but essentially nobody understands that. Instead, they see the large amount they're saving and mentally that magnifies the impact of what they're doing. From the various posts I found, an ideal, un-shaded install produces between 200 and 500 kWh per year, depending on orientation and size. Obviously any sort of shading would drop that off a cliff. Compare that with the 38 MWh (38,000 kWh) per year of primary energy that the average German consumes...
> provide the feeling of doing something about a serious problem without actually doing anything substantial.
You're wrong about this. There are a lot of people who still think solar power is only about environmental virtue-signalling and it can never compete with good old dinosaur juice. If everyone adopts balcony solar, it'll help convince these people they're wrong. At least the ones who are merely misinformed rather than dug into an ideology.
Your total energy needs figure today is completely irrelevant. Half of the so called needs are just for entertainment. Now excuse me I have to step in my SUV and drive to lake Garda Italy for the weekend at 200 km/h.
Everyone replying disagrees, but I think it's a perfect analogy: just like the backyard furnaces, these small-scale installations are inefficient, provide a negligible portion of total energy needs (<1% of total energy needs if everyone in Germany did it, from TFA), look ugly and - this is the most important - provide the feeling of doing something about a serious problem without actually doing anything substantial.