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‘Energy independence feels practical’: Europeans building mini solar farms

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Re: ‘Energy independence feels practical’: Europeans building mini solar farms

#41

Post by tjansen »

mytailorisrich wrote: post #21
tjansen wrote: post #18

Earlier quoted context omitted.

As soon as everybody is paying spot prices, balcony power stations are not economically viable anymore. Even today, on a sunny day, spot prices for electricity are either very low or even negative. The more solar power is available, the lower these prices will be. So your balcony power station is replacing electricity you could get for free anyway. At night, when you are not producing electricity, you still need to b…

To me this illustrates that with renewables (solar and wind) the key is storage. You want to grab all you can during excess production/very low prices periods and then use that for the rest of the day. You can do exactly that by buying battery packs but (1) they are more expensice pieces of kit than solar panels and (2) capacity and output of DYI/plug in systems is very limited. A quick check online also says that (i…

> You want to grab all you can during excess production/very low prices periods and then use that for the rest of the day.

Batteries help, but even that is limited in northern countries like the UK. If you look at the data, in July '25, solar produced 2.36 TWh. But in December '25, it was only 0.535 TWh: the output in summer is >4 times the winter output. So either you need to discard 75% of the electricity produced in summer, or you need truly gigantic batteries that store power produced in summer for winter. Both is not economical. Solar is far less efficient in the UK than in, for example, Florida.

Re: ‘Energy independence feels practical’: Europeans building mini solar farms

#43

Post by raverbashing »

friendzis wrote: post #25
theshrike79 wrote: post #2

Distributed energy production / storage is the key for resiliency in the future. Every solar farm doesn't need to be China Size - it doesn't even need to be a "farm", just put them on roofs. And don't let perfect be the enemy of good. Yes there are times when solar doesn't produce energy, but there are also times where it OVERproduces.

> And don't let perfect be the enemy of good. Yes there are times when solar doesn't produce energy, but there are also times where it OVERproduces. When solar OVERproduces you have to literally pay someone to consume that energy, most probably wind farms, which could be producing energy instead. So you pay actually twice. When the solar underproduces, you need to bring in alternative sources, but those now have to c…

"If you find dollar bills on the ground you need to pay someone to collect it as litter"

Charge batteries, do electrolysis, or a multitude of other uses (I know some companies do that already)

Re: ‘Energy independence feels practical’: Europeans building mini solar farms

#44

Post by pjc50 »

tialaramex wrote: post #31
pjc50 wrote: post #20

Earlier quoted context omitted.

> spot prices for electricity There are various good websites for showing the UK generation mix, but pricing seems less public. A lot seems to be done on day-ahead, which is pricing for the whole day not minute by minute. Is there a minute-by-minute ticker? Tariff? (the reason I'm asking is that I'm skeptical as to how true this is for places that aren't California)

You can see spot prices at the top of grid.iamkate.com for example. It would be nice to have some belated insight into how the bids look. Like maybe a few random hours released from a week ago? Oh, and it's half hours. You can't buy or sell five minutes of electricity, just half hours, which is why your smart meter also thinks in half hours. 48 periods per day.

Aha - that led me to https://bmrs.elexon.co.uk/system-prices , which shows that for the last week prices have been hovering in 80-180 range, and there was only one period of negative pricing during the day.

Re: ‘Energy independence feels practical’: Europeans building mini solar farms

#46

Post by leoedin »

Gibbon1 wrote: post #10
dust42 wrote: post #6

I once read an article that in Berlin the sewage system is flushed with fresh water because too many people have installed water saving toilet flushers. So plenty of people bought these water savers and now the price of water has gone up because the water that is directly flushed needs to be paid too. The 'balcony power stations' are the same thing. They get subsidised, and you even get a fixed kWh price when pushing…

I have the curse of having an mom who was a smart CPA. All this stuff root top solar, plug in solar costs at least twice what utility solar. And only makes sense when you have messed up rate setting schemes that enable arbitrage. But it's not what you want if you want to get the most GW connected as fast as possible. Like the requirements that new houses have roof top solar. You could get twice as much if you just in…

> But it's not what you want if you want to get the most GW connected as fast as possible.

I agree with rooftop residential solar. The cost per kW is high, each site is fiddly and requires far more labour and paperwork than the extra cost of adding 4kW of solar panels to a large grid scale one.

But plug-in solar bypasses most of that. The cost to the government to allow someone to buy and install a panel on their balcony is effectively nothing. A single 800W panel is not interesting, but the aggregate effect of 10% of households buying an 800W panel at the local shop is an extra 12% of installed solar capacity.

Admittedly that's less than the annual growth rate right now. But it's also almost free.

Re: ‘Energy independence feels practical’: Europeans building mini solar farms

#47

Post by glimshe »

pjc50 wrote: post #45
roysting wrote: post #42

[flagged]

Once you've bought the panel, unlike oil, that's it. The panel doesn't remember its national origin.

And panels last forever, ensuring that Europe won't have to deal with panel manufacturers ever again.

Re: ‘Energy independence feels practical’: Europeans building mini solar farms

#48

Post by throw0101c »

pjc50 wrote: post #45
roysting wrote: post #42

[flagged]

Once you've bought the panel, unlike oil, that's it. The panel doesn't remember its national origin.

> Once you've bought the panel, unlike oil, that's it. The panel doesn't remember its national origin.

Until there's a geopolitical event occurs and your supply chain gets cut off so any expansion, warranty, or replacement units cannot arrive, so you're stuck at the your current level of deployment (which may or may not be sufficient for your needs).

Re: ‘Energy independence feels practical’: Europeans building mini solar farms

#49

Post by pjc50 »

misja111 wrote: post #27

Can anybody explain how these plug-in solar panels work? I am suprised that it's possible to just plug them in to your wall socket. For instance, isn't it complicated to have their output be in perfect sync with the frequency that comes in via the electricity net? Because to me it seems that if they won't, you will have lower benefits or even a net minus after plugging it in.

> isn't it complicated to have their output be in perfect sync with the frequency

Not especially, given that the inverter has a microprocessor in it. All it has to do is measure the phase of the existing grid.

I don't have references for how it's actually done, but one obvious approach is simply to wait at each zero-crossing for a new half-cycle to cross a voltage threshold before turning on the output. This also implements the requirement to drop out if the grid goes away. It is probably also possible to measure during the "off" side of inverter output PWM, in the same way that variable frequency motor drivers work.

Re: ‘Energy independence feels practical’: Europeans building mini solar farms

#50

Post by RealityVoid »

friendzis wrote: post #25
theshrike79 wrote: post #2

Distributed energy production / storage is the key for resiliency in the future. Every solar farm doesn't need to be China Size - it doesn't even need to be a "farm", just put them on roofs. And don't let perfect be the enemy of good. Yes there are times when solar doesn't produce energy, but there are also times where it OVERproduces.

> And don't let perfect be the enemy of good. Yes there are times when solar doesn't produce energy, but there are also times where it OVERproduces. When solar OVERproduces you have to literally pay someone to consume that energy, most probably wind farms, which could be producing energy instead. So you pay actually twice. When the solar underproduces, you need to bring in alternative sources, but those now have to c…

> When solar OVERproduces you have to literally pay someone to consume that energy, most probably wind farms, which could be producing energy instead.

You don't have to do this with solar, you can just disconnect the panel and have it go a bit hotter. For producers that have a long-ish bringup time, yes, you might need to do this at time.

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