I'm thinking about putting solar panels on my house in Lisbon, but I'm not sure if it's worth it with installation prices being so high. Has anyone who's already done it managed to say how long it takes to recover the investment? And then do I need a battery or can I hook it up directly to the grid?
If your house has good sunlight conditions and high energy consumption, the payback can really be between 7 to 10 years, especially with government support that significantly reduces the initial cost. As for the battery, it's not mandatory if you're connected to the grid - actually, a lot of people choose not to have one because the grid works as a "free battery" and they still get credits for the excess they produce, but it all depends on your consumption pattern (if you use more energy at night, then a battery starts to make sense). What really matters is getting two or three detailed quotes and checking carefully whether shadows from trees, buildings or other structures interfere with your roof at different times of the year - that's where a lot of people get their calculations wrong.
In Lisbon it's definitely worth it, mainly because Portuguese state incentives cover a good chunk of the installation, which really cuts down your initial investment. A lot of people I know get their money back in 6 to 8 years, depending on how much you use and which way your roof faces, and then you basically get free electricity for another 20 years or so.
As for a battery, you don't need to connect it straight to the grid - actually, most people in Portugal do exactly that, they feed any excess energy they produce back into the grid and get credits on their bill. A battery only makes sense if you want complete independence or if your grid is really unstable, but then the cost goes way up. I'd recommend contacting a local company that does free quotes, because prices and available incentives vary depending on your municipality.
Don't fall into the trap of just looking at the installation cost without properly studying your consumption and roof orientation. A lot of people think solar panels are always the solution, but if your roof has shade from trees or buildings for many hours, the payback period gets much longer. The initial investment is really heavy, but with the support that exists (both from the State and some European funds) you can reduce it quite a bit.
As for the payback, in the Lisbon area with a good installation and reasonable consumption, most people manage to recover their money in something like 8 to 12 years, after that it's just profit. There are online simulators that can give you a more concrete idea based on your actual consumption and exact location. Ask an installer to do a feasibility study before you decide.
About battery - you don't necessarily need one. You can connect straight to the grid and that way you save on the battery, which is super expensive. During the day you use the energy you produce, and if you generate more than you consume it goes to the grid (and some distributors credit you for that). It only makes sense to have a battery if you want a lot of autonomy or if your area has frequent power cuts.
The biggest risk is relying only on the pretty numbers that installation companies show you without checking your specific situation. We see a lot of people who do rough math and then get surprised by the actual return. But it's true that in Lisbon the conditions are good - at least there's no shortage of sunlight.
About batteries: you only need one if you want total independence from the grid (and then the cost goes up quite a bit). If you're fine connecting directly to the grid, a photovoltaic system with an inverter (no battery) works perfectly - the electricity you generate is either consumed right away or turns into credits with your utility company, depending on your contract. A lot of people do this and are happy with it because it simplifies everything. A battery only makes sense if you have frequent power cuts or if you have very high electricity consumption at night, which most homes don't have.
The payback really depends on your consumption and roof orientation (facing south is ideal), but it also varies depending on what incentives you can get. Some programs still have money available, others have already run out. My suggestion is to get quotes from two or three different companies and ask them to properly analyze your electricity consumption history and how your house is laid out before you do your final calculations. It's not just their job to sell - it's their responsibility to study whether it actually makes sense for you.
Solar panels in Lisbon perform well because you get plenty of sun hours per year, but the payback period really depends on what you're paying for electricity now and how much your bill will drop. As for battery storage, most people start by connecting straight to the grid and only think about storage later if they want more independence - batteries are expensive and they're optional anyway if you already have the panel generating during the day and offsetting your bill.
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