ᐅ Are home battery storage systems for electric vehicles also not cost-effective? Costs of charging station and battery storage
Created on: 11 Aug 2020 07:54
A
annab377
Hello everyone,
I am planning a 15 kWp photovoltaic system for our single-family house and garage. Currently, without an energy storage system, since according to the latest information, it is still not economically viable. It is often advised against for that reason. Does this apply only to normal household use, or would it be different if you have an electric car?
I have a relatively long commute of 80–90 km (50–56 miles), so I’m considering leasing an electric car.
For that, of course, I would need a wallbox (as the interface between the energy storage system and the car) and an energy storage system. It does sound interesting because I could save a few thousand euros on diesel, and energy storage systems and electric cars are currently subsidized as well.
What additional costs should I expect? According to ADAC, a wallbox with 11 kW charging capacity costs about 500 EUR (e.g., HEIDELBERG Wallbox Home Eco). Accordingly, I would also need an energy storage system with a somewhat larger capacity. With an electric car (e.g., VW ID.3, but no Tesla), the payback period should be significantly shorter, right?
Let me know what you think.
Best regards
I am planning a 15 kWp photovoltaic system for our single-family house and garage. Currently, without an energy storage system, since according to the latest information, it is still not economically viable. It is often advised against for that reason. Does this apply only to normal household use, or would it be different if you have an electric car?
I have a relatively long commute of 80–90 km (50–56 miles), so I’m considering leasing an electric car.
For that, of course, I would need a wallbox (as the interface between the energy storage system and the car) and an energy storage system. It does sound interesting because I could save a few thousand euros on diesel, and energy storage systems and electric cars are currently subsidized as well.
What additional costs should I expect? According to ADAC, a wallbox with 11 kW charging capacity costs about 500 EUR (e.g., HEIDELBERG Wallbox Home Eco). Accordingly, I would also need an energy storage system with a somewhat larger capacity. With an electric car (e.g., VW ID.3, but no Tesla), the payback period should be significantly shorter, right?
Let me know what you think.
Best regards
Well, it’s not really something far off in the future anymore. Nowadays, everything works smoothly, meaning you can charge solely from the surplus energy generated by your own roof, and so on. The only issue is that hardly anyone wants to pay for the technology.
Basically: Why bother? It works just fine without it... I can always just go outside and plug in or unplug the car whenever I want.
Basically: Why bother? It works just fine without it... I can always just go outside and plug in or unplug the car whenever I want.
What most people install on their roofs is a 9.9 kWp system, which means that even with perfect south-facing orientation and a Type 2 wallbox, you can’t really reach 11 kW charging at noon (which is mostly just marketing talk for fast charging). Current vehicles now have a 40 kWh battery. In reality, you can probably fully charge two vehicles on a Sunday during summer. During the week, that’s unrealistic. For example, for a 40 km (25 miles) one-way trip, you will need to start charging by Wednesday, which is not feasible without drawing power from the grid because you only get home around 5–6 p.m. There is no realistic scenario where you can charge without grid input unless the storage system or the photovoltaic system is oversized—definitely not in autumn or winter. This doesn’t mean electric cars aren’t cost-effective to operate—they definitely are—but under normal conditions, you have to give up the idea that you can charge an electric vehicle with your own generated power alone. On the other hand, Corona, with regards to working from home at least in summer (May–September), has given me a daytime charging window during the week.
Using the vehicle as a storage system (in the sense of a home battery) is the most impractical option. The charging and discharging losses are significantly higher than with a home battery.
Using the vehicle as a storage system (in the sense of a home battery) is the most impractical option. The charging and discharging losses are significantly higher than with a home battery.
Mycraft schrieb:
Well, it’s not really that much of a far-off idea anymore. Nowadays, everything works smoothly just using the surplus from your own roof, but hardly anyone wants to pay for the technology.
Basically: Why bother? It works fine without it... I can just go outside and plug or unplug the car whenever I want. That’s exactly how I do it, no problem. It’s no different than telling my wife to only run the washing machine, dryer, stove, and oven after 10 a.m. and to mostly avoid heavy electricity use after 6 p.m. And honestly, that’s not even a radical approach or behavior. Because if you ignore this kind of optimization regarding electricity consumption, the solar installer’s calculation won’t add up after 11–13 years.
Zaba12 schrieb:
Most people install systems of 9.9 kWp, which means that even with a perfect south-facing orientation and a Type 2 wallbox, you can’t actually charge at 11 kW at noon (which is really just marketing hype for fast charging). Are there still meaningful limits on kWp, or do they no longer make sense?
Why only 9.99 kWp when 15 or even more kWp could fit on roofs facing east-south-west? Should I just stick with 9.99 kWp as well, or what?
(As far as I know, there is a 30 kWp limit, but that’s probably difficult for most typical single-family homes.)
I’m already thinking about selling my almost 3.5-year-old car, and leasing an electric vehicle might not be the right time yet. Maybe in 3–5 years, once there are changes in the battery storage or photovoltaic-compatible wallbox market. Or if politics change something regarding taxes on self-consumption?
Zaba12 schrieb:
Using the vehicle as a storage system (in the sense of a home battery) is the most nonsensical idea. Here, charging and discharging losses are significantly higher than with a home battery. I don’t agree. The storage in the vehicle is free, while a home battery costs at least 1,000 euros per kWh. For most cars, that would mean storage costs of 30,000 to 80,000 euros! So where are the big losses? And we don’t even need to talk about the investment in your battery. Since many people work from home or have part-time jobs, at least one car is almost always at home.
I find this to be one of the most interesting developments right now.
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