Germans turn to balcony solar panels to save money
france24.com
france24.com
I installed 14.5 kW of PV panels on the barn roof a few years ago and hooked them up to a 10 kW hybrid inverter. Hybrid inverters can divert energy (from the PV panels or from the net) to a battery which can be used at a later stage to feed consumers in the local installation or to backfeed to the net. Since we currently have a contract which allows us to sell energy at market rates we do not have a battery yet but I don't know yet what the next contract (in 2 years) will look like. Assuming that we can no longer sell at market rates I'll install around 60-80 kWh in battery capacity to soak up excess production and dump the rest in the water heater etc. If we ever get a hybrid or electric car/tractor/whatever I'll add battery capacity so as to be able to charge those with excess energy. By that time we'll be close to ready to go off-grid which is fine by me, electricity prices here in Sweden have skyrocketed due to the demand from (mostly) Germany for excess capacity since you shut down your nuclear power plants. The more transmission capacity is built in the Baltic, the higher our prices get.
Do you have a source that shows that shutting down nuclear power plants has in any way influenced German power import? I'd doubt that. Power is imported when it is cheaper to import it than produce it ourselves (there has not been a situation yet where Germany couldn't meet it's own demand).
Power is imported when it is cheaper to import it than produce it ourselves
After shutting down the remaining 6, then 3 nuclear power plants it became cheaper to import power from Sweden - which used to be blessed with relatively low electricity prices due to to the large hydro and (diminishing) nuclear generation capacity - than to generate it in Germany. While this might have been positive for Germany and for electricity producers in Sweden it is a definite negative for electricity users in Sweden who have seen their prices skyrocket. As to the direct effects of the nuclear shutdown there's quite a bit written, e.g.
https://www.cleanenergywire.org/factsheets/qa-germanys-nucle...
4) What changed in electricity imports and why?
For the first time in many years, Germany became a net electricity importer in 2023. The trade balance for electricity switched from 21 TWh of exports to 22 TWh of imports in the same period. Imports have risen despite sufficient plant capacity in Germany to cover domestic demand entirely. In March 2024, the country announced the shutdown of seven more coal-fired power plant units after the winter, as they are no longer needed to guarantee supply security.
This leaves aside other costs involved with the nuclear phase-out [1] and the knock-on effects of the increased energy prices as well as lower guaranteed availability which is part of the cause of German deindustrialisation. If you doubt whether this actually happening I invite you to peruse a search engine of your preference on the subject which is more effective than me linking to a number of articles from many different sources.
[1] https://olivierdeschenes.weebly.com/uploads/1/3/5/0/13506865...
> Imports have risen despite sufficient plant capacity in Germany to cover domestic demand entirely. In March 2024, the country announced the shutdown of seven more coal-fired power plant units after the winter, as they are no longer needed to guarantee supply security.
Because it answers his question and it is relevant in the context of Germany shutting down its nuclear power plants since this created a gap which needed to be filled with imports. Had those plants not been shut down there would not be a need to import power at the scale Germany currently does, especially not given the fact that power from existing nuclear power plants running on an existing load of nuclear fuel is far cheaper than imported power. With nuclear power the large majority of costs are concentrated in the construction phase - including all the costs incurred due to regulations - as well as the decommissioning stage. Fuel costs - including those of treating and storing nuclear waste - are but a fraction of the total costs. This means that once you have a working nuclear power plant you want to run the thing at full capacity as long as possible to recoup those initial costs and to earn income to finance the decommissioning of the plant at the end of its life. The plants which were shut down were not at the end of their useful lifetimes and could have produced many TWh of energy still - e.g. Isar 2 produced around 11 billion kWh per year and supplied around 3.5 million households with electricity which it could have continued to do for many years still.
Our inverter is built for high-voltage batteries (120V to 580V) so I'm aiming for either using expired EV batteries or - once prices go down more - LiFePO4 battery stacks. As it stands prices are still too high which - calculated over the life span of the batteries combined with compound interest on the investment - makes power from such batteries cost around the same as power taken from the 'net. Battery prices are steadily going down so this situation should change, hopefully within 3 years they'll have gone down so far as to make it a worthwhile investment.
Why would you do that? I'd rather sink all the surplus electricity into a cryptocurrency miner than just give it away to the grid.
But installing solar on your own roof with your own funds, and then giving the energy away for free to a for-profit corporation? How does that make any financial sense?
Posing the question, is there a valid technical reason or is it just institutional conservatism and inertia ?
Traditionally, a power grid only had medium and large power plants, and they are not only connected to the power grid but also a control network. Adding many small power generators poses a problem in how you communicate and coordinate with them.
"Connecting Solar to the Grid is Harder Than You Think" https://www.youtube.com/watch?v=7G4ipM2qjfw
This is true (as far as I know) for ALL inverters, apart from "off grid" solutions, so workers can turn off power on a street level. If that wasn't the case, there would be no way for technical staff to make sure that lines going to multiple homes (with solar) are powered off.
When you backfeed like that your neighbors will draw on your power - but they will attempt to draw more than you can provide and so your circuit breakers will trip. The only way backfeeding could be an issue is if you have a very large generator and the area islanded is only a couple neighbors such that the total power use is less than the theoretical max of your house.
That said, linemen are trained to either treat all wires as live or short them to ground. They can never be sure they are not in that rare exception case and mistakes can be deadly.
Is there something about German electrical systems that let's this just work? I feel like everything I've read about solar for the US isn't this simple.
The safety reasons are actually valid. You can not safely turn off a power-topology with a N-to-N setup. The providers just cant life without that power..
"Protectionist reasons" sounds nice to people who already hate big corporations, but it doesn't make a lot of sense. When the grid is down, it's down. There is no revenue to protect at that point. The actual thing they might want to protect against is big solar farms competing away revenue from fossil fuel plants, but as you'll notice such solar farms are entirely legal.
You need a special inverter for it to not blow up when the grid is running, and even the cheap $80 grid tie inverters on amazon do this sort of checking before activating.
<yawn> This argument again? People have been saying the same thing about backup generators forever and it's just not true in practice.
From the POV of your solar or generator the resistance of the neighborhood is basically a short. Breakers will pop if generator and/or or voltage will collapse if solar. If you are out of sync and the grid comes back your hardware will be what leaves the chat, not the grid's
Linesmen are trained to ground their work first because the far bigger hazard to them is miscommunication among upstream coworkers. Better to liquify fuses or hardware than people when that happens.
If "everyone" had solar or a back fed generator it could be a problem but we'll cross that bridge when we get to it. And that bridge would be crossed procedurally on the utility/linesman side (grounding your work mostly already does but more would likely be desired). They're not stupid. They're not gonna trust their lives to the assumption that the hardware upstream and downstream is going to do what they expect.
>"Protectionist reasons" sounds nice to people who already hate big corporations, but it doesn't make a lot of sense. When the grid is down, it's down. There is no revenue to protect at that point. The actual thing they might want to protect against is big solar farms competing away revenue from fossil fuel plants, but as you'll notice such solar farms are entirely legal.
The protectionist angle is that if generation was more local rather than regional there would be much more competition because it would become more economically realistic for municipalities to strike out on their own and/or parter with each other and do so in order to shake off existing overpriced or incompetent utilities.
it's also technical requirement, you have to synchronize to existing sine wave.
the main reason such device is bad idea is that you might have power at exposed pins. In this case inverter will not produce any power until you already plugged into socket.
I have a friend who works for the grid operator in our country. He says that if you, even for a few seconds, become a power generator (as opposed to a load) without being authorized to, they'll notice and there will be an investigation.
edit: Sounds like they do just plug in into the power outlet, and you're allowed to supply power back to the grid. Which makes sense, and is very different from what we have one country over.
Source: i installed a set of solar panels myself.
But that overcurrent protection is huge. Even more if your house walls are flammable.
Germany has many rented apartments compared to eg the US. If you own a house, those systems make little sense. But for Germany, where many rent an apartment, it’s attractive for many. And the only way for many to ever profit from solar.
> The high consumer prices for electricity in Germany are a result of grid fees
Grid fees are a coverall for "making sure the whole thing runs", which in my mind covers "making sure there's gas (at least that's what we use in the UK) to cover the shortfall when it's not windy". The Gas stations need to be able to spin up to handle the demand, so it's an abritrage where you really want to maximise the amount of wind you use, while paying as little overhead to keep the gas ready to go. It's like being on-call, and having your on-call pay amortized into your regular pay.
You can get dynamic contracts based on the day ahead price in Germany. You pay a negative price for the electricity there. You still have to pay a transmission fee and taxes, so the actual end price is almost never negative though.
Of course sometimes you also pay much more than normal contracts.
Also without merit order, you'd still pay close to the most expensive source on the spot market. It's a consequence of the open grid where demand and supply has to match and price is not fixed.