ᐅ Photovoltaic Experts – Improving Our Electricity Consumption?
Created on: 14 Nov 2016 21:46
N
Nafetsm
Hello,
we are currently looking into photovoltaic systems and considering doing something good for our electricity consumption 🙂 Since our usage is relatively modest (about 2500 kWh), only a small system makes sense for us. I’m thinking around 3 kWp to 3.5 kWp, aiming to maximize self-consumption, possibly combined with a battery storage system that we might add later.
For now, we’re just thinking about operating the photovoltaic system alone. We would orient the panels east-west to get sunlight for as long as possible. There is almost no shading. We are planning on about 30% self-consumption – is that realistic? The rest we would have to feed into the grid.
We don’t want to finance the system but pay from our own funds, since otherwise the payback period hardly makes sense.
Question: how much administrative effort is involved in terms of taxes (specifically VAT advance returns and annual accounts)? This is the part that worries me the most. Is the benefit of the system reasonable compared to the paperwork involved, or does the bureaucracy take more time than expected? Have you regretted it? How is your system running? Are you satisfied with the yields and the feed-in? Or do you have more effort than expected for maintenance, billing, etc.? How large is your system? And is 3 to 3.5 kWp enough to eventually add an electric car?
I’m very curious to hear about your experience.
Patrick
we are currently looking into photovoltaic systems and considering doing something good for our electricity consumption 🙂 Since our usage is relatively modest (about 2500 kWh), only a small system makes sense for us. I’m thinking around 3 kWp to 3.5 kWp, aiming to maximize self-consumption, possibly combined with a battery storage system that we might add later.
For now, we’re just thinking about operating the photovoltaic system alone. We would orient the panels east-west to get sunlight for as long as possible. There is almost no shading. We are planning on about 30% self-consumption – is that realistic? The rest we would have to feed into the grid.
We don’t want to finance the system but pay from our own funds, since otherwise the payback period hardly makes sense.
Question: how much administrative effort is involved in terms of taxes (specifically VAT advance returns and annual accounts)? This is the part that worries me the most. Is the benefit of the system reasonable compared to the paperwork involved, or does the bureaucracy take more time than expected? Have you regretted it? How is your system running? Are you satisfied with the yields and the feed-in? Or do you have more effort than expected for maintenance, billing, etc.? How large is your system? And is 3 to 3.5 kWp enough to eventually add an electric car?
I’m very curious to hear about your experience.
Patrick
K
Knallkörper15 Nov 2016 14:34Whether self-consumption is realistic or not depends, in my opinion, largely on your usage pattern.
If laundry is mainly washed and dried concentrated on Saturday evenings, the electricity for that won’t come from the photovoltaic system. If you work during the day and like to cook in the evening, the same applies. And so on. We have also calculated this ourselves. A return on investment is hardly to be expected despite a very large roof area with precise south-facing orientation. If at all, it makes sense to install a 10 kWp system right away, because then the acquisition cost per kWp decreases and payback becomes more achievable.
A thermal storage tank is currently too expensive to be economically viable.
If laundry is mainly washed and dried concentrated on Saturday evenings, the electricity for that won’t come from the photovoltaic system. If you work during the day and like to cook in the evening, the same applies. And so on. We have also calculated this ourselves. A return on investment is hardly to be expected despite a very large roof area with precise south-facing orientation. If at all, it makes sense to install a 10 kWp system right away, because then the acquisition cost per kWp decreases and payback becomes more achievable.
A thermal storage tank is currently too expensive to be economically viable.
In my opinion, photovoltaic (PV) systems can be economically viable when self-consumption is as high as possible. A system that only feeds electricity into the grid is hardly profitable nowadays, especially with smaller system sizes – the profit mainly comes from purchasing power at a lower cost. Systems around 7 kWp and 10 kWp are considered “magic” sizes because, as Knallkörper already mentioned, the cost per kWp decreases significantly when aiming for these sizes.
To increase self-consumption, you can invest in “smart” solutions, meaning technology that manages electricity usage. However, this involves additional costs. Alternatively, you can ensure that major appliances run at times when the PV system is likely to produce a lot of energy, for example, running the dryer on a timer set for noon, but definitely not at night. However, the dryer is probably one of the largest appliances that can be reasonably scheduled. Owners of heat pumps find it much easier to increase their self-consumption.
You might think that increasing self-consumption through battery storage is a good approach, but batteries are still very expensive and have a limited lifespan, so the cost-benefit calculation doesn’t usually add up.
Of course, you can charge an electric vehicle with PV-generated electricity to increase self-consumption. The downside is if the car is not at home during the day and needs to be charged in the evening when there is little sunlight. Also, considering the battery capacity, the PV system plays a secondary role. Depending on location and weather, your roof might deliver about 3 kWh per day, but if your Tesla is plugged in, it will want to charge up to 90 kWh within 2 hours.
In your scenario, I would not expect any return on investment. The system is too small and therefore too expensive to install, self-consumption is doubtful due to the overall low electricity demand and the lack of large, controllable appliances.
To increase self-consumption, you can invest in “smart” solutions, meaning technology that manages electricity usage. However, this involves additional costs. Alternatively, you can ensure that major appliances run at times when the PV system is likely to produce a lot of energy, for example, running the dryer on a timer set for noon, but definitely not at night. However, the dryer is probably one of the largest appliances that can be reasonably scheduled. Owners of heat pumps find it much easier to increase their self-consumption.
You might think that increasing self-consumption through battery storage is a good approach, but batteries are still very expensive and have a limited lifespan, so the cost-benefit calculation doesn’t usually add up.
Of course, you can charge an electric vehicle with PV-generated electricity to increase self-consumption. The downside is if the car is not at home during the day and needs to be charged in the evening when there is little sunlight. Also, considering the battery capacity, the PV system plays a secondary role. Depending on location and weather, your roof might deliver about 3 kWh per day, but if your Tesla is plugged in, it will want to charge up to 90 kWh within 2 hours.
In your scenario, I would not expect any return on investment. The system is too small and therefore too expensive to install, self-consumption is doubtful due to the overall low electricity demand and the lack of large, controllable appliances.
We have received an offer for a photovoltaic system with a capacity of 6.35 kWp, planned to generate 5,183 kWh per year, including a Senec storage system and cloud service.
The cost for the photovoltaic system alone would be over €10,000, and the same amount for the Senec storage (5.0 kWh).
The calculator from the Umweltinstitut München was somewhat helpful! (Umweltinstitut München Solarrechner .xls; search online).
We have not made a decision yet! (Possibly install the photovoltaic system first, then add the storage later!).
The cost for the photovoltaic system alone would be over €10,000, and the same amount for the Senec storage (5.0 kWh).
The calculator from the Umweltinstitut München was somewhat helpful! (Umweltinstitut München Solarrechner .xls; search online).
We have not made a decision yet! (Possibly install the photovoltaic system first, then add the storage later!).
10,000€ gross or net? If net, then discard the offer and get more quotes. Overpriced.
A 5kWh battery storage is probably oversized for the system size anyway, as you will never fully charge it. The storage is obviously highly overpriced, each kWh will easily cost you over 40 cents, so it’s never worth it. Prepare for it and check again in a few years to see if it might be worthwhile then.
A 5kWh battery storage is probably oversized for the system size anyway, as you will never fully charge it. The storage is obviously highly overpriced, each kWh will easily cost you over 40 cents, so it’s never worth it. Prepare for it and check again in a few years to see if it might be worthwhile then.
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