I see that new 280Ah LifePO4 cells are available on Ali for R1400/kWh. And the prices will just keep coming down - residential storage to go off grid is going to be a no brainier...

15 hours ago, Brani said:

Here is something you said 

Posted 9 hours ago

   12 hours ago,  Brani said: 

So Eskom say customers with PV are being subsidized by the customers with no PV.

That's so. Remember that Eskom are talking about customers they supply directly. 

Now in Johannesburg we already have a segmented bill for people on the post paid tariff. They pay fixed costs for running the account and for the connection and then they pay for consumption. On prepaid you pay more for consumption but the flat charges fall away. 

Now I'm on prepaid AND I have a hybrid system. So City Power bear the cost of maintaining a connection to my house and I can give them heck if there is a problem. But they are not even breaking even on that connection. 

Yes I said that. You're not the guy putting words into my mouth and attacking on the basis of me adhering to some imagined ideology. 

And I stand by that. It costs City Power money to maintain a connection to my house, but they don't get much payment for it. It would be ridiculous of me to assert that I'm subsidising somebody else. 

Quote

 

It comes to the same thing, your argument in different words is that PV customers are subsidized by others and network charge will make it fair. My argument is that it is the  punishment to us.

This may depend on where you live. In the area supplied by City Power, post paid customers have had that network charge for a decade or more. Now I didn't like it and I was happy to say goodbye to it when I switched to prepaid. But I understand why it's there. It costs the city the same to provide a 60a single phase connection to any house, irrespective of how much they consume. I acknowledge that, because it is so. 

If we have some other supply and are satisfied that we are self sufficient then the remedy is simple. 

If, like me, you think that well, maybe one day I'll need a bit from the grid then you need that connection and somebody has to cover the cost of keeping it in good working order. 

I'm happy to be in my present situation, BUT I can see the provider's POV as well. 

Quote

They created the rule for me when I was power hungry. Now that I’m in a diet, they want to charge for the network. What difference does it make for them what method I used to reduce my consumption. I could have used gas, cook on fire, switch everything off or use PV. Result is the same to the utility... loss of income.

Yes.  But OK. Forget it's Eskom (a word guaranteed to spoil the mood at any dinner party). Suppose it's BobVolt, a private company, supplying to Jhb. What do you think they will do if consumption drops but they bear the same burden of maintaining infrastructure? They will do the only thing they can do - increase prices. 

I do think the press have been mischievous here. They are inventing the notion that Eskom are punishing those of us with solar panels, ignoring the other factors that you mention. 

Eskom are merely trying to split the bill into a fixed component for having a connection and a charge per for usage and they are wanting to do that for all users. It may have the affect of increasing bills for solar users in some areas, but I don't see anything to suggest that that is their motive, that they are being vengeful. 

Quote

it would be like saying if I go to McDonalds and order chips only instead of a Big Mac meal, they are entitled to charge me the same. After all, they have to pay salaries and bills to provide that building where I can buy a lot or a little.

Like previously stated, we have been double taxed for being progressive and environmentally friendly.

 

Quote

As for Eskom, “duck curve” problem is a false NARRATIVE

Maybe. Eskom should be able to provide data to support that claim. This should be the least arguable part of their proposition. If they can show the duck curve then that argument is over and the debate moves to what should be done about it.

They will get asked about this, and if the data isn't there then they have a considerable amount of egg on their face. So I would expect that they have the data. They also appeal nearly every day for a reduction of use between 17:00 and 21:00. You may not be causing that, and I am pretty sure that I'm not because 5pm is about when my batteries start discharging. That doesn't mean it isn't happening. 

 

Quote

 

SSG are not increasing the peak, they are making the duck’s belly fat. If there was no PV, peak would be higher. Most of us don’t need to normally use Eskom at peak hours. Solution for Eskom is the same solution that every solar household is forced to do - store the excess energy and use it when demand is high.

Well see above, who said it's all? What you say is the case for hybrid systems, but solar doesn't have to be hybrid. 

I agree on that solution, but doing it requires lots of land and lots of outlay and a technology other than the batteries we have right now which will need replacing at regular intervals. 

Edited January 31, 20215 yr by Bobster
Spelling

On 2021/01/31 at 2:08 PM, Vassen said:

This thread has become a storybook. Takes some time to follow through. 
 

What I don’t get is 2 things. 
First, what exactly is the maintenance that needs to be done to the infrastructure. I don’t see how’s it’s costing the municipality anything extra to maintain a connection to my house. Unless majority of the people in my area are switching over to solar and are all using very little from the grid, then I could see how it would cost them extra if for example the substation were to blow. However, this is not the case. In my complex alone with 40 units, I am the only one that has solar. In my area, there are very few people with solar. If this grows in the future, then they just need to plan better and actually do some work for a change. In any case, it’s not like someone is actually maintaining the grid by themselves where they are actually monitoring and manually telling someone to add more coal to the furnaces. It’s all freaking automated.

Nothing lasts forever. If I built a factory I'd need to make provision for servicing of equipment. Most months there won't be any spend, but every now and then I'll have to dip into what I've been setting aside.

Thinking of where I live, over the last couple of years they have replaced nearly all the overhead lines in the suburb. OK... that was mostly about theft. The new lines are aluminium which is less attractive to thieves. Also we've had a pole that got struck by a truck, another two that needed extra support because they were leaning at an ever increasing angle. Just down the road from me a person lost power to their property. City Power investigated and found the main feed to the property that had gone open circuit. They put in a temporary overhead feed whilst they wait for permission from JRA to excavate. All of this costs money.

And really, there are lots of things that don't happen to each of us every day but that happen which cost money.  They may not have had to do anything for your supply recently, that doesn't mean that supplying the city/country/area doesn't cost money.

NB! I'm in Johannesburg, fed by City Power. We've had a flat monthly fee for a connection for over a decade (when I started paying attention to the detail of my municipal bill, it may be 20 years or more). So maybe I don't see this as a big change because we already have it. Unless you're on the pre-paid tariff, in which case they charge youy more per kw/h to try to make up some of the lost charges on your bill. 

If this is a new thing for you where you live, here is the other thing to consider. The general opinion is that Eskom should be split into at least two entities - generation and transmission. This also creates a way to let IPPs into the game and even offer different tariffs (as is done in the UK). In which case how does the transmission side of Eskom make enough money to keep running?
 

Quote

Secondly, even if you have a grid tied system. It doesn’t really matter. The infrastructure is already there and designed for a certain capacity. During the day, shops / businesses, are all using a lot more power than at night. I don’t hear anyone complaining they have to ramp up production for this. In the evening, businesses close, using less power while household usage increases. It’s the same thing that would happen over weekends and holidays, household consumption would increase since people are doing things differently. If there’s suddenly a cold day, people pull out heaters. I haven’t heard people say this is a bad thing. I have heard eskom say the grid is constrained, but in most cases they manage. 

AIUI the problem is that each grid segment can handle a maximum load, yes, but there is a problem with excess electricity. It has to go somewhere, the grid, including the local substations, is not a storage facility, it conveys from generator to consumer. So, one explanation I've read, in any situation where there is too much power in the grid they have to reduce generation. Then they have to start increasing it later in the day. This may not even be easily predictable because solar generation varies with weather conditions. But even if it were, the explanation continues, having to ramp generation up and down is an extra management burden and the more the output of the generators varies, and thus how hard you drive the input side varies, the less efficiently they run and thus the more the average cost per kw/h.

I remember reading recently that the efficiency figures that some car manufacturers claim these days are not that great if we look at ALL internal combustion engines, because those that run at a constant speed for long periods of time (EG cruise ships) show much greater efficiency because they are not accelerating and decelerating all the time. 

So, me no engineer, but it seems to me that the famous duck curve, if indeed Eskom have such, can cause problems and costs. There are reports out of parts of Australia with high rates of installation of grid-tied systems that speak to these problems.

I wonder if shops do use a lot more during the day. Their fridges still run at night. If they're restocking the shelves at night then they have to keep some lighting going.

And this is where data comes into play. Eskom either have some kind of theoretical model that shows what will happen if X% of your consumption is replaced by grid-tied systems, or they have actual data showing that that demand curve is there. They have been saying for some time now that peak consumption time is 5pm to 9pm, this is not new. If they do actually have the data then the discussion moves to what to do about it.

We here should also know better than to settle for a vague term like "solar", and I hope the people who are going to examine Eskom's proposals know better or consult with experts. I have a hybrid system. If my neighbour has a grid-tied system then we both have "solar", but we have very different systems that will have different implications for Eskom.

 

Edited February 1, 20215 yr by Bobster

I should add that there is currently a special, subsidised rate for low income users and Eskom are saying that they plan to retain that.

16 hours ago, Vassen said:

 

I agree to this partly. It does cost money but some of this should come out of insurance. For example cable theft or someone knocking down a pole. Some things are maintenance and should be planned for accordingly. 

 

How is this any different from a sudden cold weather where people suddenly use heater or after a few hot days and the weather is decent and people stop using aircons or after a few cold days when the weather is pleasant and people don’t need heaters. They would still need to worry about demand management. 
 

The place in Australia you refer to is a very different scenario as most people have grid tie and have been incentivized to do so.

There the problem is even worse as they need to worry about sudden cloud cover that will drastically affect the required load.

It's a grid. It's for transmitting, not storing. It is a different country with a different subsidy scheme, but there are similarities as well. I've been making the point all along about grid-tied systems and it's been discussed on this forum before. It is a problem in Australia, because they have so many small systems feeding back in to the grid. I see no reason why the same can't happen here, especially in CT where they are at the very least offering a reasonable deal on sell-back.

 

Quote

 

South Africa is very very far from that. It’s a small minority of people that have solar and those that do solar have them together with batteries to be able to deal with load shedding which by the way is rumored to have been created initially because of corruption and not because there was actually a problem. 

Well we all hear rumours. Rumours are things that get around but are untested. The most reasonable conclusion really is that Eskom shed load BECAUSE they can't meet supply. I'm not asking anybody to be anything less than angry about that, but that's what it is - they have big problems and sometimes can't meet demand. 

We all hear stuff and in this day and age we can check quite a lot of it. Like the last time Pikitup went on strike and how long it lasted.
 

As to whether is or isn't a duck curve, what this whole aspect of what Eskom are saying will come down to is that they have data that shows this is a problem, that we're heading for this problem (because they have reliable data about the rate at which grid-tie systems are being installed) or they are sucking it out of their thumbs. This will come out in the wash.

Remember that they don't just get to set tariffs. They have go to the regulator and justify the tariff increases they ask for (and the last couple of years Eskom have not been happy with the gap between what they've asked for and what they actually got, so NERSA are not there to rubber stamp whatever Eskom say). What has happened here is that Eskom want to motivate some fundamental changes to NERSA (or they had a management indaba and somebody's power point presentation got leaked).

 

Quote

Yes, fridges do run but they are not opened and closed as often so will not use as much power. Further, aircons don’t need to run permanently at night as not much heat is being lost, some lights are on but for a shorter time. 
 

I’m in jhb and am fed directly from eskom. My bill is already split into a daily network capacity charge which I get charged R4.38 per day. Even if eskom don’t provide a electricity for the day, I am still charged this capacity fee. 

pikitup is the same. Every year workers go on strike for weeks and are not paid. Yet, pikitup charges residents a monthly fee and have no expenses to pay. It’s actually profitable to pikitup if their workers strike, they get their standard income and their expenses are much lower. 

As I said, COJ have had a split bill for years - for customers on the post-paid tariff - so this seemed like a big yawn to me. Now you're saying that Eskom already do it. So what's the fuss about? My guess is that a lot of folks don't read their municipal bill past the bottom line. They pay that unless it starts looking unreasonable in which case they pay some arbitrary amount and raise an objection with Eskom/Municipality so the matter gets investigated. I've had to explain to several people in my neck of the woods how what Eskom call IBT's work, that there are fixed charges and variable charges etc. They either don't read the bill or see stuff that had never occured to them (one person I can think of started looking at bills and called me up to ask what this "rates" thing was). So now (my guess) folks get all alarmed because they read about a multi-component electricity bill when they've had it for years but never noticed.

If you're paying 4.38 a day that's 120ish a month (OK... add VAT and round properly and  it might get up to 140ish). That's significantly less than City Power customers pay.

Can you not convert to pre-paid? City Power customers can with some conditions (your entire municipal bill must be paid up to date. You must actually own the property, not just live there Etc). It costs money to convert (they will always quote you and leave the final decision to you) and you pay more per kw/h because there are no flat fees. But if you're not using many kw/h it's a better deal (though City Power are working hard to close the gap which annoys me because customers who pay in advance are good for your business). It cost me R400 odd to convert, and the month after conversion I got a big bill because they were billing me for everything on my meter up to time of conversion, but it took about 4 months to move into a position where I had a nett saving. 

Edited February 2, 20215 yr by Bobster
Brevity, clarity

I don't understand why the 'duck curve' is such a challenge. If they could incentivise industry to use that excess which is wheeled through the grid, they could be selling electricity they didn't even generate. Most businesses operate during the day. The sun shines during the day. Where's the problem?

 

i find this discussion VERY interesting, although some guys seem to get to hot under the collar, i think we are all in the same boat as per Bobster, and ultimately have the same frustrations... just a few things to consider....

 

the problem is exactly in that.... most guys do not use electricity only during the day.... almost ALL the heavy users with very little exception use electricity around the clock, and not just during the day.... we have a factory of about 500 people and have a day and night shift... and most times our autoclaves run during night shift, meaning we have peak during night time.... think of example the mining industry, most mines run operations 24 hours around the clock in shifts, if not that, the very least the processing plants and most services are still running 24/7 even if the operation is not at 100% production.... cooling and ventilation on a mine works on a completely different method than household ac... they have fire suppression and lifeline systems that never should go offline as is the same with ventilation and cooling, same with critical services that need to be supplied to aux or refuge bays underground.... think of industries like refineries like the likes of sasol etc, also around the clock operations.... any type of high temp furnaces, the guys in the galvanizing industry etc, the gold processing plant at DRD.... my wife is a electrical engineer at eskom/siemens, and i have but a very limited insight into their dealings and challenges, problem is mainly the corruption, which is core to all issues were the state has their dirty paws in the broth.... the poor guys on the ground just takes the grunt for it.... if you take the top 15 industrial customers of eskom you probably have a ridiculous figure like 70% of their consumption (can't remember the exact figures but is something crazy like that), so saying that guys using less on their fridges and lights during nights helps and that the duck curve is not an issue is not really applicable, yes eskom asks for guys to switch of swimming pool pumps and geysers etc etc during load, but that is because they are already so close to the cliff, and every bit helps because they are already so deep down the rabbit's hole.... and most days no longer have any spare capacity to ramp up.....

 

I remember the Richardts Bay aluminium smelter saga from a few years ago where the consumers were subsidising them due to a very generous contract Eskom had with them. 
I don’t know what the outcome of that was but my logic tells me that scenarios like that one continues to this day.

We often see reports that government departments have not been settling their accounts.

Combine that with fraud and I have no sympathy for them. We know their (extremely well renumerated) labour is far more than required. They also tried to get rid of their housing subsidy book some years ago. Rumour had it their workers got 100% loans at 0% rate. Think of how they must have panicked to start paying market related rates.

So much of their misfortune is home made.

On 2021/02/01 at 2:56 PM, Bobster said:

but it seems to me that the famous duck curve, if indeed Eskom have such, can cause problems and costs

this is the average SA hourly electricity consumption. If anything PV would actually help flatten the curve 🤣

3 minutes ago, Fuenkli said:

this is the average SA hourly electricity consumption. If anything PV would actually help flatten the curve 🤣

No. Most large PV installations have no battery storage, so they feed all the available PV power into the grid. Which means they cause a big dip in the demand from the utility centered around midday. They do little to nothing during the morning and evening peaks. This is what the utilities don't like. They have pretty much the same peak loads as before, but the base load becomes very small. This causes problems as they have to ramp generation up and down much more quickly and by a greater margin. In fact this is one time that I actually agree with eskom. If you have a PV system and are using the grid as storage, i.e. Feeding back excess power during the day and then buying it back at night so that your average for the month is basically 0, you have still used the grid and there are costs involved for the utility to provide you with that connection, so I agree that there should be a base connection fee to cover the fixed costs. The price per kWh can then come down.

13 minutes ago, Stanley said:

They do little to nothing during the morning and evening peaks

That is true. I also agree, that a reasonable charge to use the grid is justified. I do however not buy the argument, that PV will overload the grid during the day (at least not for the foreseeable future). We desperately need more clean electricity to push out the very dirty coal power. And to cover the morning and evening peaks more wind power must be installed.

1 minute ago, Fuenkli said:

a reasonable charge to use the grid is justified

Disagree totally. If they can charge me I must be able to penalise them for loadshedding and power failures.

I get supplied by the munisipality who owes them R3b btw.

When last could they meet their demand 100%

They keep their lips flapping - thats all.

No discussions of any kind will save their (and the ainncee) asses.

 

22 minutes ago, Johandup said:

No discussions of any kind will save their (and the ainncee) asses

I agree. Eskom in its present form will die soon. But a well functioning country needs an electricity grid. The grid will work best if as many people as possible are connected to it and share the building and maintenance cost. Looking at what is happening around the world gives us an idea what we have to do here in the future. Power generation and distribution has to be privatized. We have to be able to sell our PV surplus at a profit. Coal, gas and nuclear has to disappear (to dirty and expensive). Massive PV and Wind capacity has to be installed. Electricity distribution (across SA and Africa) has to be expanded.

19 hours ago, Fuenkli said:

this is the average SA hourly electricity consumption. If anything PV would actually help flatten the curve 🤣

Well, what is "PV"? A system like mine that stores power in batteries for use at night will help flatten the evening curve, that's for sure. I don't sell back because it's simply not worth my while. But if enough people do?

If that graph is recent that is with existing solar systems already in place. So not much flattening yet - especially in the evenings.

19 hours ago, Fuenkli said:

That is true. I also agree, that a reasonable charge to use the grid is justified. I do however not buy the argument, that PV will overload the grid during the day (at least not for the foreseeable future). We desperately need more clean electricity to push out the very dirty coal power. And to cover the morning and evening peaks more wind power must be installed.

YEs, but that that should be big farms that are on the supply side of the grid and which whoever is controlling the grid can manage. Off shore wind farms for example. Solar farms in the Karoo.

18 hours ago, Fuenkli said:

I agree. Eskom in its present form will die soon. But a well functioning country needs an electricity grid. The grid will work best if as many people as possible are connected to it and share the building and maintenance cost. Looking at what is happening around the world gives us an idea what we have to do here in the future. Power generation and distribution has to be privatized. We have to be able to sell our PV surplus at a profit. Coal, gas and nuclear has to disappear (to dirty and expensive). Massive PV and Wind capacity has to be installed. Electricity distribution (across SA and Africa) has to be expanded.

This market can get very interesting. In the UK you now essentially buy from the suppliers who feed into the grid. So you can chose to buy from a supplier who generates exclusively from renewable sources or employs some other practice that you like. Or you can shop around for a TOU tariff that suits your situation. 

I did some shopping around using the address that I lived in when I was a kid. One supplier (Scottish) said that they would beat any other deal I could get by 1 penny per annum. 

Well, Eskom clearly have supply and demand issues right now

On 2021/02/02 at 4:27 PM, Saint said:

yes eskom asks for guys to switch of swimming pool pumps and geysers etc etc during load, but that is because they are already so close to the cliff, and every bit helps because they are already so deep down the rabbit's hole.... and most days no longer have any spare capacity to ramp up.....

Poor us. Here in Jo'burg the water supplier wants us to not run pool pumps during the day because, they say, this increases evaporation. So they ask us to run the pool pumps in the evening.

But then Eskom ask us to NOT run pool pumps in the evening because that's their peak hours. So we have to bugger around with timing switches and try to run the pool pump in the wee hours for enough hours a day.

On 2021/02/02 at 4:46 PM, Vassen said:

I have also read somewhere that households with solar installation are not allowed to be on prepaid. Possibly to eradicate this issue as well as the problem with people accumulating lots of credits on summer and using it in winter.  So a classic example of existing rules not being enforced but the powers that be wanting to change the rules so that more people need to suffer. 

I should think that this depends on who your supplier is. In Jo'burg you have to go onto a special tariff and have a special meter installed (at your cost) if you want to resell. The rates they pay and the cost of that meter mean that I will actually lose out if resell because what I can sell back will never cover the cost of the meter and the monthly fixed charges that will appear on my account. 

So at present I am on pre-paid, have solar and don't resell. This may be a loop hole that they intend to close, but it's going to be difficult for them because I do feed the meter every now and then, just to keep a nice credit on it because I use a little each month and want to buy units now because they aren't going to get any cheaper.

So at what point do they say that you don't use and don't pay anything so you must switch? 

I don't think they can do that. I think they are going to continue upping the kw/h rate and will reintroduce the fee per month for having a pre-paid meter that was added and then removed the last 2 years.

 

I must say I’ll pay Eskom gladly their 0,78c per kwhr which they charge the local robbers. Plus my account will always be up to date. Promise ...

I don’t feel under obligation to pay for the caders..

 

On 2021/01/30 at 5:01 PM, Bobster said:

You do understand that it's sub-editors who have said that Eskom are "punishing" PV users? Eskom are not using that language. 

You are also attacking language thst I haven't used. The words "first and foremost" are not mine and you are not correcting me.

Indeed you seem to ignore the points I do raise and "correct" me on things I haven't said. 

I'm also no kind of libertarian. Leftist? Well we'd need to discuss some things that aren't appropriate to this board to figure out who is left or right of whom. 

It might be more helpful if you deal with what I actually say rather than what you imagine my political leanings to be. 

You actually raised an interesting technical point here. Why do you need to synchronise with the grid if you don't use it? Or is 10 kw/h a minimal figure you can survive on but you actually use more? 

I do not agree that it is the editors' language, it is pretty plain and clear to the journalists what Eskom are doing. Whether it is "punishment" or communism, it's the same thing.

Please be careful when accusing me of misquoting you, if you read carefully, you will see that this is not the case.

For decades Eskom never had this problem. In their 1994 they were the most efficient utility in the world and in 1990 they supplied more than half of Africa's power. In 2001 they received the "Power Company of the Year" award in New York. Was their demand pattern any different? I am not convinced that is was, consumers still used power in pretty much the same way back then as they do now, morning and evening peaks. The difference is that Eskom and municipalities implemented cost effective ways of managing this, for example the ripple relays on geysers. The electricity supply was run by competent professional people who were qualified, respected and innovative.

This is not the case today.

Should I pay more for the fact that I have a connection, just because I hardly use it? I do not see the fairness in that, but somehow you seem think that it is. Unfortunately you and I already do, it's in all the government bailouts that we have paid in the past 25 years, and all the bailouts and corruption that we will pay in the future. Despite this fact, they now want us to pay more.

So, even if I request to be physically removed from the grid, I will continue to have to pay Eskom for their bungling, stealing and sheer incompetence. The only way not to pay them would be to emigrate, which I have chosen not to do. The fact that I am forced to accept this, does not make it right.

Eskom wants to make the bitter pill sweeter by creating an argument and justification for taking more money from me.    Fortunately, I am not morally confused, and nothing that anyone can do or say is going to convince me otherwise.

I will do everything within my locus of control to ensure that I minimise every single cent that Eskom tries to squeeze from me.

Edited February 6, 20215 yr by YellowTapemeasure
typo

22 hours ago, Bobster said:

Poor us. Here in Jo'burg the water supplier wants us to not run pool pumps during the day because, they say, this increases evaporation. So they ask us to run the pool pumps in the evening.

But then Eskom ask us to NOT run pool pumps in the evening because that's their peak hours. So we have to bugger around with timing switches and try to run the pool pump in the wee hours for enough hours a day.

If everyone simply starts using their power the way they want to at any time they want to, then soon eskom will break down totally and the economy will crash completely, then we can start the process of rebuilding

When Eskom asks me to reduce load/usage I turn on my kettle and aircon...

8 hours ago, YellowTapemeasure said:

I do not agree that it is the editors' language, it is pretty plain and clear to the journalists what Eskom are doing. Whether it is "punishment" or communism, it's the same thing.

Please be careful when accusing me of misquoting you, if you read carefully, you will see that this is not the case.

Until now you've rarely directly addressed anything I've actually said, "corrected" me (as you would have it) on things I haven't  said (I provided an example) and chucked around these political terms like they're insults and like you know what they mean. I've met very few people who think that "libertarians" are "leftist".

These are labels you are imagining, you don't know me well enough to know if I am either of those things (I can't be both) and I'm steering clear of politics here.

I'm not engaging with you any further in this particular discussion.

And now this :

https://mybroadband.co.za/news/energy/386776-eskom-to-hike-electricity-prices-by-over-15.html

 

I fail to see why this topic attracts so much negativity.  CoCT and other municipalities already charge a basic grid connection fee and usage on top.  They do this with water as well and even more they then have a deemed sewerage charge based on how much water you use.  Having fees that more directly reflect the usage of something is far better than them taking the easy way out and simply billing for usage at a flat rate.  Heck, I would go further and have time of day based rates - more expensive at peak times and cheaper at off peak times.

The fee isn't targetted at only people who have PV panels.  The fee will be paid by everyone with a consequential reduction in the usage amount.  It's not really different to owning a car.  There are basic per month costs that aren't much related to usage (insurance, finance, etc) and there are costs related to usage (fuel, brakes, tyres, etc).

Just because something might disadvantage you personally, doesn't mean it's the wrong decision or unfair in some way.