Habeck claims anyone could quite easily use 10% less energy

575 posts in this topic

3 hours ago, Gambatte said:

And they keep telling us PV is getting cheaper, so the system now should cost less than in 2019, not more.

Demand has increased massively over the last year, and supply is struggling to keep up. Particularly around the Eifel, tradesmen have more jobs than they can deal with and are quoting crazy prices for any work.

The three quotes I have had for 12kwh with a battery have also all been around the 30-35k mark (depending on which battery etc), but only one of them claimed they would install all elements this year. As we use about 3kwh per year the amortisation would be around 15 years (even allowing for price increases and assuming I switch to an electric car and increase consumption), by which stage the system will no longer be functioning anywhere near 100%.

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27 minutes ago, dstanners said:

the amortisation would be around 15 years.

Can you please elaborate on this?

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36 minutes ago, dstanners said:

The three quotes I have had for 12kwh with a battery 

you mean 12kWp? WIth what Akku size?

When I asked quotes I was specifically asking for 3000 kWh Akku, bigger we would either never charge up, or never use. It turned out although small Akkus, 3000-5000 kWh, in principle exist, they refused to quote us, they said most of the cost is in the overhead like installation etc. In our case, even if the price was the same, the added value of any Akku bigger than 3000 kWh would have been zero.

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40 minutes ago, Gambatte said:

Can you please elaborate on this?

Ok, I've dug up one of the quotes from June this year. Sadly my scanner is broken, so I've tried to put what I think are the key details below.

The quote was for a 14kwp system with a 10kw battery and car charger.

Excluding vat and allowing for the subsidy on the car charger, they have modelled this as a year one cost of 26,880 + annual costs of 215 (125 Betriebskosten and 90 Verbrauchskosten), but less the annual benefits of 353 (Einspeiseverguetung), and the saving on the electricity costs which we would otherwise have to buy starting at 1,225 in year 1 rising each year by an assumed 5.75% thereafter.

So, based on their model, I would have the initial costs repaid on year 15.

This also assumes that 26880 in 15 years is worth the same as it is today (which is not really realistic), and assumes that there will be no significant drop off in performance of either the battery or the panels over that time frame (which also seems a best case scenario). 

 

 

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@dstannersthanks a lot for the info. Interesting.

This is based on THEIR models. More often than not, these models are skewed in favor of the vendor, and they tend use unrealistic data deliberately set to present you a more favorable picture than reality. The easiest for them to manipulate is the amount the Akku will lower your grid reliance. This because (unless you already own PV and are a data nerd, like me) you haven't yet had the chance to gather your own data and compare it with what they are telling you.

 

The conclusion I reached is based on the data I measured, every day during 1 year, for our very own usage.

My suggestion is to go ahead with PV, but no Akku.

Either way good luck with the project.

 

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I was reaching a broadly similar conclusion: namely, a smaller (cheaper) system might work for me. A battery isn't so crucial as I work from home, which means I can use the power when it is being generated (and if/when we go for an EV, it would be sitting on my drive charging during the day). I am still waiting for a quote for that system though (as I mentioned in an earlier post - the tradesmen here have so much work, they are all seeking the most profitable jobs first).

We have also agreed to get solar thermie this autumn too, for the same reason (i.e. we can use the hot water during the day). Even excluding subsidies, that will be less than 10k, and given our gas bills are through the roof, this pays itself back far sooner. I bought a pellet oven a few months ago too, with pipework to cover two floors, so our gas consumption should plummet. 

 

 

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A newspaper report claims that people who generate their own power with solar panels use more energy, and even draw more energy from the grid. Maybe they feed more into the grid too.

 

Getting a solar generator seems a lot of fuss and expense, one should surely be wary of the figures. Better to spend the money on warm clothes maybe.

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On 16/08/2022, 10:36:59, Fietsrad said:

The chance of a nuclear katastrophe might be very small, but the katastrophe might be very big, no-one knows.

And if it happens it won't respect national borders. A French disaster would cause as much of  a problem as a German one.  Better for Germany to be in control of it's own regulation, and more importantly to stop burning brown coal.

Shutting down nuclear power in Germany was a dumb idea on all sorts of levels.

 

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I would still like to stop current level nuclear power, but only when renewable s  are in a  form can be relied on. To do that, we need new laws / regulations, that force all new housing to install renewable tech and better insulation. I would probably go further, and force the same for when property is sold or bought.

 

Its still going to take a very long time ....  

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15 hours ago, Fietsrad said:

people who generate their own power with solar panels use more energy, and even draw more energy from the grid.

Not us. 

Last 12 months we bought from the grid 1337 kWh. The other 1066 kWh that we consumed came directly from our PV.

A normal household consumption is probably near 3000 kWh, or 4500-5000 kWh if you believe PV vendors :D

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23 minutes ago, Gambatte said:

Not us. 

Last 12 months we bought from the grid 1337 kWh. The other 1066 kWh that we consumed came directly from our PV.

A normal household consumption is probably near 3000 kWh, or 4500-5000 kWh if you believe PV vendors :D

 

I noticed you talked about a "small" 3000KWh battery, which seemed surprisingly large to me, when you think about EV batteries. So that would be a whole year's consumption? Which obviously would make no sense. Or have I got that wrong?

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3 hours ago, Dembo said:

I noticed you talked about a "small" 3000KWh battery, which seemed surprisingly large to me, when you think about EV batteries. So that would be a whole year's consumption? Which obviously would make no sense. Or have I got that wrong?

Sorry, my fault, I added one k that I shouldn't have added.

Small Akku is like 3000 Wh. As I wrote, although in principle they are on the market all of the Akku vendors  we contacted refused to quote it to us. Not exact wording but the message was like: price for big or small is almost identical, so we rather sell you something that takes more space, pollutes more to manufacture and eventually to dispose, more expensive to dispose at the end of its 10yr lifetime, and is even more useless to you. 

Big Akku is 10000 Wh.

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37 minutes ago, Dembo said:

I noticed you talked about a "small" 3000KWh battery, which seemed surprisingly large to me, when you think about EV batteries. So that would be a whole year's consumption? Which obviously would make no sense. Or have I got that wrong?

 

Indeed it would be nice to store summer PV electricity for winter use. But the numbers just don't make sense, you would need an unrealistic Akku, it would cost like few 100k and have the size of an LKW. So at best one stores daytime PV electricity for night use (still the numbers don't make sense, but it's a different story...).

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51 minutes ago, Gambatte said:

Sorry, my fault, I added on k that I shouldn't have added.

Small Akku is like 3000 Wh. As I wrote, although in principle they are on the market all of the Akku vendors  we contacted refused to quote it to us. Not exact wording but the message was like: price for big or small is almost identical, so we rather sell you something that takes more space, pollutes more to manufacture and eventually to dispose, more expensive to dispose of after its 10yr lifetime, and is even more useless to you. 

Big Akku is 10000 Wh.

Maybe I am wrong, but 3000Wh does not sound much !, My kettle is 3 KW.

 

Ok, the kettle boils the water in like 2 mins then switches off, 

 

Does that mean the 'system' automatically takes power of the grid, or does that mean that the washing machine stops while I get some hot water for a cup of tea ?

 

See also http://birt.org.uk/energy/battery/battery1.html

 

 

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2 hours ago, yesterday said:

Maybe I am wrong, but 3000Wh does not sound much

Again:

the key numbers you should look at are 1) how much you feed into the grid each day, not on average, and 2) how much you draw from the grid each day, not on average.

In fact, for each day of the year you should take the minimum of these two numbers.

If today you feed 1 kWh and you draw 50 kWh, today day a good battery is 1 kWh.

If tomorrow you feed 50 kWh and you draw 1 kWh, tomorrow a good battery is 1 kWh.

If you had a 50 kWh Akku, on both days 49 kWh of it would be unused.

 

In fact, you normally EITHER feed a lot and draw very little (summer), or viceversa (winter). That's why small Akku are better suited. Still overpriced, but this is a different story.

 

Of course one could argue that, from my example above, you feed/draw on average 25.5 kWh to/from the grid each day. This is true, but it is also useless and dangerously misleading (unless you make a fat living by selling oversized overpriced Akku, in which case it comes very handy...).

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I’ve been reading interviews with experts in energy and the opinion seems to be that we’ll likely see prices per kWh for electricity of 1€ and more in the next months.
 

I have a bad feeling about the company that made us an offer - lied too much for my taste- for the photovoltaic system and already contacted several more. If I get offers I’ll write you (Gambatte), if that’s OK. Your math is just awesome :)

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Be aware that for the sake of battery life, there should be a good margin, you should not drain it to zero every day.

I feel the issue with Akku is that for some systems this makes installation more complex and expensive. At some point most of the cost in a country like Germany will come from the setup service, not the materials. So a small Akku might become very expensive per kWh of capacity, due to installation overhead.

 

Also this whole math changes a lot depending on your consumption habits. Let's say If you only charge 2 EVs at night, then a larger Akku makes sense. For a short commute, both together will require around 10kWh per day. So quickly your math on Akku changes again.

 

Even without EVs, your nightly consumption might justify it.

I'm eagerly waiting for the day I decide to design a complete system and spend several weeks making all the math!

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43 minutes ago, MikeMelga said:

Be aware that for the sake of battery life, there should be a good margin, you should not drain it to zero every day.

I feel the issue with Akku is that for some systems this makes installation more complex and expensive. At some point most of the cost in a country like Germany will come from the setup service, not the materials. So a small Akku might become very expensive per kWh of capacity, due to installation overhead.

 

Also this whole math changes a lot depending on your consumption habits. Let's say If you only charge 2 EVs at night, then a larger Akku makes sense. For a short commute, both together will require around 10kWh per day. So quickly your math on Akku changes again.

 

Even without EVs, your nightly consumption might justify it.

I'm eagerly waiting for the day I decide to design a complete system and spend several weeks making all the math!

 

Yep. you're right. Regarding cars: My wife only needs her car when the weather is too bad for cycling and her commute is around 15km both ways. I need my car max. three times per week (I try two..) for a commute of 160km both ways. So I'm planning to recharge the car during the day as much as possible: when the battery is too low I'll just take her car.  This won't work during the winter months, but then nothing will.

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My wife's boss went from Tesla hater to owning a Model Y, so now it's "safe" for her to take our Tesla to her company to charge once a week, free.

Her company provides services to German automotive, and they in general despise Tesla. But it's finally changing...

 

I still feel the general solution for charging cars, especially for people without garage, is to charge at work.

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1 hour ago, MikeMelga said:

My wife's boss went from Tesla hater to owning a Model Y, so now it's "safe" for her to take our Tesla to her company to charge once a week, free.

Her company provides services to German automotive, and they in general despise Tesla. But it's finally changing...

 

I still feel the general solution for charging cars, especially for people without garage, is to charge at work.

 

We'll be able to charge at our company at some point this year but not for free, rather at market prices.

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