ᐅ Photovoltaic Systems & Energy Storage *General Discussion Thread*

Hello everyone,

Since I have come across a few posts in other threads here in the forum regarding energy storage systems for photovoltaic installations and I am personally very interested in the topic, I found some more information during my research online.

Until now, I really believed that due to the currently low electricity prices compared to battery storage systems, these are not cost-effective.

The following study mainly refers to theoretical data and calculations. Nevertheless, it clearly shows how the situation can vary under different conditions.

On page 13, you will find a table with the various systems considered.

Under section 3.4.3
- it is mentioned, for example, that a photovoltaic system with storage has a feed-in power limit set at 60%.

Under section 4.2
- the system sizing is well compared.

Under section 4.5.1
- different financing examples are listed again, also taking into account KfW funding, along with various electricity price increases.

The best storage system was the Senec Home G2. Senec was able to offer such a competitive price due to the affordable replacement battery and inverter. Has anyone already installed one or informed themselves about it, or can share more general information on the topic?

Hopefully, this information is helpful to others as well.

Best regards,
Andi

The link will probably disappear shortly...

Battery technology is still evolving quite rapidly at the moment, so the article is likely outdated by now.

nathi schrieb:
The link will probably disappear soon...

Battery technology is currently developing quite rapidly, so the article is likely outdated by now.

Good morning nathi,

yes, I agree with you that these systems are evolving very quickly now, and maybe some people have found more up-to-date values or test results during their research or elsewhere.
I think this topic is becoming more interesting month by month and year by year, which is why I started a separate thread about it. I also found quite a bit in other threads here in the forum, but always just bits and pieces.

p.s. Regarding the link, I didn’t know, so I added it along with the comment, but you were right and I will remember it for next time 😉

A storage system is not worth it over 100 years.

Example calculation:
7,000 kWh are produced. Without storage, the self-consumption rate is optimistically 20%, meaning 1,400 kWh can be used directly. With storage, self-consumption could reach 40%, which is 1,400 kWh more than without storage. With a feed-in tariff of 20 cents per kWh, this is a 5 cent/kWh difference compared to the market price, which translates into savings. For 1,400 kWh, this results in a huge 70 (!!) euros per year earned through the storage system.

On the other hand, there are the annual costs for the batteries. With an average lifespan of 10 years, the storage system would have to cost 700 euros per 10 years to break even.
However, batteries typically cost about ten times that amount.
Now you can calculate how much storage you get for 700 euros.

Conclusion: You’d be better off burning the money in the fireplace—at least that way you’ll get some warmth.

Elina schrieb:


With a feed-in tariff of 20 cents

There is not much to add to the comments by @Elina. Just a small correction: In January 2015, the feed-in tariff for newly registered systems (< 10 kWp) was only 0.1256 euros. This would result in about 175 euros before taxes in the example calculation.
The original poster plans their build for 2018, by which time the tariff will likely be even lower.

Otherwise, I agree with @Elina and hope for significantly lower prices and longer lifespans for batteries, which probably won’t happen anytime soon.

Hello,

Elina schrieb:

With an average lifespan of 10 years

That is not entirely correct. Our partner in this sector guarantees 7,000 charge cycles, which roughly corresponds to a lifespan of 20 years. Besides, the market is currently very dynamic; in other words, storage prices are dropping significantly as Chinese manufacturers strongly push into the market.

Regards, Bauexperte