[dust42]

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 into the grid.

The problem is that in the end it will become more expensive for everybody because at times you have a surplus driving the whole sale electricity prices into the negative while still paying fixed prices for injection into the grid.

To make this economically viable, you have to have everyone paying spot prices. Everything else is just green ideology driven inefficiency.

Just to make it clear, I think renewables are an important option for the future. But to make them a viable option of the electricity energy mix, supply and demand, storage and grid capacity need to be taken into account.

Last not least, there is plenty of low hanging fruit to drive CO2 emissions down: drive up the truck tolls. Currently you have potatoes farmed in Germany, driven to Poland to get washed, transported to Italy to be converted to french fries and transferred back to Germany into the super markets.

Same goes for home office, during Covid it was possible for many workers to continue with their work. Does an accountant need to drive to an office every day? Nope. How many business trips could be replaced by a video call?

If the CO2 emissions problem is to be solved rather sooner than later, the money has to be spend efficiently as there isn't enough of it.

[Xylakant]

The price of water has gone up for a multitude of factors. One of them is water savings in general, but not primarily because the sewage system requires regular flushes. The reason is that water gets paid per qubic meter and includes a fresh water and a waster water component. The assumption is that almost all fresh water you use ends up as waste water. Now, the grid has a very substantial fixed-price component that's largely independent from the actual current volume being used. Putting pipes in the ground and maintaining them there is an actual costly endeavour. If water use now drops, and the baseline cost remains stable, then it's entirely expected that the price per volume rises. It's simple math. The same baseline cost needs to be brought in via less volume.

This will also happen to people that use residential gas. As less and less people use residential gas, the maintenance of the gas network gets distributed among less and less customers.

> The 'balcony power stations' are the same thing. They get subsidised, and you even get a fixed kWh price when pushing into the grid.

They are subsidized on purchase, but the price they get when pushing energy into the grid is by default fixed at 0. The network accepts the power, but there's no payment. It's also capped at 800W delivery, meaning that at peak power generation, you'd earn a whopping 5 cent an hour with the current subsidy for full scale solar power. So in practice, the only benefit owners have is that they draw less power from the net which is much more attractive because of the pricing structure. You can, optionally, register your balcony power station as a regular solar power plant, but then you're subject to a whole bunch of rules and regulations (for example you need a suitable elctricity meter etc.). This option is generally not attractive for such small power generations.

Fundamentally, though, the same issue as with the water and gas network exists with all localized (solar) power generation. If more and more people use the grid only as a backup, or for winter energy needs, then the overhead of maintaining the grid will have a larger cost contribution to the total cost of electricity.

[watwut]

> 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.

What is this supposed to mean? You flush less water, therefore water price is more expensive, because flushed water needs to be paid too?

[myrmidon]

Presumably that the water bill (for tap water) was priced to cover both tap water provisioning and sewage works. But people using (free) rainwater to flush toilets ruined the pricing model, making the tap water price go up.

I honestly don't see the problem, it's probably still worth it (because society still needs to provide less tap water and saves there).

[coryrc]

GP is partly right. Most of the cost of sewers is fixed cost: employee salaries, building and maintaining X kilometers of sewers, etc. Some is variable: chemicals, but a small part.

If you, a single person, cut your water usage in half, you pay half as much. But if everybody uses half as much, the system still needs about the same amount of funding. So now you double the per-unit price, and everybody pays the same they were before spending money on water saving features. In this case, even if each person used half as much water, the total water needed isn't cut in half because the sewers need more water to function.

(Also, water isn't "used"; most of it's transported, cleaned, transported, dirtied, cleaned again, transported)

[mytailorisrich]

Perhaps that sewers need a certain volume of water flowing in order to function correctly. If that water does not come from toilet flushes, etc then they pump water into them to compensate.

[goodpoint]

The conclusion that saving water is greenwashing is just wrong.

[dust42]

> This is just made up.

Or not. https://www.welt.de/wirtschaft/article152318777/Wassersparen...

Edit: parent changed his answer, I have included it now.

[tjansen]

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 buy the expensive electricity from fossil plants.

The reason why personal solar installations are profitable is that you can buy electricity for fixed prices from your local power company. You pay the average of the vastly different low (or negative) prices during the day and the extremely expensive prices on windstill nights. Solar allows you to use your own electricity when the average is below spot prices, and get power for much less when the price you pay is cheaper than spot prices. It's like a state-approved scheme to play the market in the name of decarbonization while actually increasing everybody else's prices and possibly even CO2 emissions.

[tpm]

> As soon as everybody is paying spot prices

Which is never, because even then you are still paying some sort of taxes on top of the spot prices and also network fees.

The price of electricity from the network also has to include the price of delivery, while homemade electricity only has to recoup initial investment.

Of course this means given enough home installations (in places with enough sun) the price of electricity from the network will rise, more people will install their own stations, some will even disconnect, rinse and repeat. I read somewhere this exact situation is already playing out already in Pakistan.

[pjc50]

> 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)

[tialaramex]

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.

[pjc50]

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.

[stuaxo]

Wow, £100 per MWh and 12% is fossil fuels in the mix at 10:48am ... a bit more Solar adoption and maybe that 12% could go away, it's morning after all.

[mytailorisrich]

It's windy (41% wind). Solar is not great all day long and all year long in the UK (8% solar at the moment, it is a cloudy day).

[mytailorisrich]

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 (in the UK) peak spot prices are usually 7am-10am and 5pm-9pm, which are basically when demand picks up or hasn't dropped yet while solar panels are useless...

[tjansen]

> 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.

[mytailorisrich]

In the UK wind contributes more to the grid that solar (not unexpected). Overall the issue with either or both is still that production varies widly over time including within a day.

With solar specifically you have the obvious day/night cycle, which makes storage required to make the most of it.

[vablings]

This is why smart meters are important to providers, they can more accurately model the spot pricing adjustments which means that you actually use LESS fossil fuels. Also most new meter installs support bi-directional metering

[Gibbon1]

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 invested the money in a conventional solar farm.

[leoedin]

> 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.

[ZeroGravitas]

US costs for rooftop solar (at build time or retrofit) are misleadingly high.

In the EU build time solar roofs overlaps with utility costs but up to 1.5x , and retrofit is say 2x.

To give context. In the EU adding solar to new homes is cost competitive with running existing(!) nuclear plants. In the US only utility scale is competitive with that.

Retrofit rooftop solar is about the same as new nuclear in the US, retrofit is 25% cheaper than new nuclear in the EU.

[pjc50]

> Like the requirements that new houses have roof top solar.

As a CPA child, you should understand that the same money is very different when it comes out of a different account.

(everyone watches two critical numbers, income tax and government deficit, so the #1 priority is to hide capital spending somewhere else, in this case by moving it to buyers of new homes)

[ben_w]

While true in general, I suspect that this won't change house prices as (I think) those are more driven by supply-demand imbalances rather than the actual costs, and that the increase in costs will go into someone else's profit margin, which may be some mix of the builders (although they're famously opaque from all the sub-contracting) and the land owners.

[Ray20]

Regulations like these make the entire renewable energy sector seem like a crazy scam and greenwashing.

They might not have much of an impact on property values (certainly no more than the plethora of existing building regulations). But we shouldn't be surprised if as a result people vote for a candidate whose campaign promise consists of picking up a grenade launcher and blowing up windmills.

[ben_w]

On the one hand, it's been obviously economically a good idea to require this for about a decade, both because PV is cheap and would pay for itself even at full price and also because doing it construction time is cheaper than doing it later.

Even moreso now, because PV is now cheaper per square metre than tiles or fences, even if you don't hook it up to the grid afterwards.

On the other hand, this is the UK so maybe. They did Brexit and somehow Farage hasn't been deported for the consequences.

[pjc50]

> They get subsidised, and you even get a fixed kWh price when pushing into the grid

Neither of these is going to be true for the UK balcony scheme (you can't get export generation pricing unless it's an MCS-certified install).

> drive up the truck tolls.

The price of diesel is going to do this anyway very soon.

[phyzome]

And exactly as soon as your prediction comes true, it will become obvious for people to buy battery banks that perform temporal arbitrage. Which will then mostly solve the issue.

[vrganj]

Thinking of this in terms of markets is the real ideologically driven inefficiency.

[dust42]

You can spend every euro or dollar only once. If you consider CO2 emissions a critical problem, then you should spend every single dollar as efficiently as possible. Obviously independence of fossil fuels has a value too, as the current situation in the middle east shows.

It would make much more sense to import (renewable) electricity from Spain to Germany than strawberries.

[myrmidon]

No this would not make more sense.

Grids are not set up to move significant percentages of national consumption over longer distances, and expansion is slow, expensive and prone to nimbyism.

Countries already struggle to move electrical energy inside their own borders (e.g. Germany: north=>south), shifting double digit percentages of national consumption across Europe is not gonna happen any time soon. Germany alone plans to spend at least ~€100bn over the next decade on this (internally, not on connecting Spain!).

Much more effective to focus on local generation first than to try and rely on slightly better conditions for solar panels half a continent away.

[vrganj]

You shouldn't be spending euros or dollars at all. The economic system is the ideology holding us back.

[danaris]

So...what should we be spending?

Gold coins? Pesos? Cows? Inferior-quality copper ingots?

It's entirely possible that you have a good point, but if so, it's gonna need a whole hell of a lot more context to elucidate.

[pjscott]

If money ever starts looking particularly illusory, try thinking in terms of the underlying resources that markets allocate.

That's 'resources' viewed as expansively as possible, everything from the specialized labor-hours of people who know how to do quality control on bulk-manufactured photovoltaics to the ore used to make ball bearings in the factory all the way to the guy in charge of managing a grain elevator that was involved in making the bread for the sandwich one of the janitors had for lunch. The web of collaboration between all these far-flung people who mostly don't know each other, too vast and intricate to fit in any living mind, is how we currently get most of our material stuff.

... And in a conventional market system, the core of how those people coordinate their efforts is money. The price that each person is willing to buy something for or sell it for sends a signal about how much they care about it relative to other things. And markets are one popular way of aggregating that information, helping guide society's cooperative efforts in the direction of what people care about.

There are various allocation systems that don't involve money, both theoretical and historical. Community-based mutual reciprocity with a reputation mechanism to discourage freeloading, for example, can be found all over the place in pre-modern history because it worked – as long as your community was small enough that you can realistically all know each other. Or, back in the 20th century, there were a number of efforts to scale up operations research toward the level of nations, since suddenly we had computers fast enough to handle e.g. non-trivial linear programming. (The successes and failures were both instructive.)

--

Coordination problems are hugely underrated in political discourse. So when I hear people say things like "The economic system is the ideology holding us back", I always have to wonder: how carefully has this person thought about a what a viable alternative would look like?

"I dislike the current system" is only the first and most trivial part of a real reform agenda; the next part has to be "... and here is how to meaningfully change it in a way that doesn't result in disaster, with a detailed discussion of mechanism design and a look at relevant historical prior attempts. [Insert essay or hyperlink here.]"

[Panzer04]

Sadly a lot of people look at our economic system through an ideological lens - how it allocates resources is, to them, driven by political, cultural and social motivations. The fact that by far its most important purpose is resource allocation is often completely ignored.

Rising petrol prices here in Australia draw criticism against fossil fuel wholesalers - as if they are doing this solely to screw over Australians. The fact that these high prices are caused by an actual lack of resources and that the higher prices are driving a reallocation of resources to those who need them most (ie. most willing to pay for them) is not on the radar for many.

[radialstub]

> The fact that these high prices are caused by an actual lack of resources and that the higher prices are driving a reallocation of resources to those who need them most (ie. most willing to pay for them) is not on the radar for many

Careful using words like "need". The resources are allocated to the economically most efficient sectors. Since if you are economically efficient, your profits are higher and can afford to pay more than others.

[vrganj]

Any human system is inherently ideological.

"It’s not only our reality which enslaves us. The tragedy of our predicament when we are within ideology is that when we think that we escape it into our dreams, at that point we are within ideology." - Slavoj Zizek

> The fact that these high prices are caused by an actual lack of resources and that the higher prices are driving a reallocation of resources to those who need them most (ie. most willing to pay for them) is not on the radar for many.

This, for example, is a deeply ideological statement. Do I really need something most just cause I can pay more for it? Does the billionaire need the mansion more than the homeless person needs some living space?