Jump to content

How do I calculate the amount of PV needed?


ToughButterCup

Recommended Posts

4 minutes ago, jack said:

I'm performing my civic duty to punish them whenever they drop the ball

Except you are personally punishing me, you rascal.

 

I wonder if the real problem is simply that grid power is too cheap to create real inovation.

And I say that paying 24p/kWh day rate and 9p/kWh night rate and have just paid my 'winter bill' when my E7 water cylinder was bust, so £260 for that quarter.

Things are fixed now but when I calculate the total cost with meter rental and VAT, the unit rate is not often below 16p/kWh and that is using 80% night rate.

day night split.jpg

Link to comment
Share on other sites

Just now, SteamyTea said:

Except you are personally punishing me, you rascal.

 

That assumes that if the government weren't paying me for this, they'd be doing something better with the money. Seems unlikely given their track record!

  • Like 1
Link to comment
Share on other sites

3 minutes ago, jack said:

doing something better with the money

Can't think what, maybe £350 million a week on the NHS.

 

Or just pay for a new sign for the side of the bus that says.

'We are robbing you'

trickle down.jpg

Edited by SteamyTea
Link to comment
Share on other sites

27 minutes ago, jack said:

 

That assumes that if the government weren't paying me for this, they'd be doing something better with the money. Seems unlikely given their track record!

 

The "government" isn't paying you anything. The subsidy comes from other electricity consumers via the electricity companies.

Link to comment
Share on other sites

3 minutes ago, SteamyTea said:

Yes, but the government, well parliament, set the legislation, so it is their fault really.

 

 

Not their smartest ever move, IMHO.  It seems that every time the government decide to introduce incentivisation schemes associated with renewables or energy reduction they screw up, often very badly indeed.  It really annoys me that every scheme they introduce ends up being abused by installers who increase their charges in order to either collect the subsidy for themselves as extra profit, or to increase the price to consumers because the government have created a rigged market.

  • Like 1
Link to comment
Share on other sites

1 hour ago, JSHarris said:

 

I disagree strongly.  Our house has no access to the gas grid and for obvious reasons I didn't want to burn oil, coal or wood, plus we had no where we could safely fit an LPG tank if we'd wanted one.  That left is having to use electricity, and so it makes perfect sense to divert self-generated electricity to the Sunamp PV and use it for our primary hot water system.  By doing that we massively reduce our demand on the electricity grid, and, in summer, reduce the level to which the local grid shuts our inverter down (it's a rural area and the grid voltage regularly hits the 253 VAC upper bound on sunny days).  The same goes for the diverter that feeds my car charger.  It seems far better to use excess locally renewably generated power to charge my car on an ad hoc basis, than it does to charge the car from the grid, perhaps at a time when the grid load is already high.

Umm... not really that convinced (although the inverter shutting down because the grid is limited would be one of the cases where I have no problem with it). The subsidy regime is one of the aspects which has contributed to your decision to use a heat pump for heating and resistance heat for hot water (albeit with a preheat tank from the heat pump). Over the course of the year, the net energy flow from grid to your house will be greater than if you had used the heat pump for water heating, even with the defrost issues you have, since you would only be export-limited for a small fraction of the time. The net result is that the subsidy forms a perverse incentive - it's a relatively modest impact in your case, but is still there. Most people with Immersuns or similar would have otherwise used mains gas to heat their water, and there the difference is rather bigger.

 

1 hour ago, SteamyTea said:

One problem with variable pricing is that the government has dictated that our energy bills need to be 'simpler', so less opportunity to have variable pricing.  Not sure how this sits with the energy supply companies who probably want to use variable pricing.

The theory is that you'll be able to download some sort of annual energy consumption profile which you can then use to shop around on comparison sites and get the best deal for your circumstances. I think it'll be a while before that happens, however.

 

30 minutes ago, SteamyTea said:

Except you are personally punishing me, you rascal.

 

I wonder if the real problem is simply that grid power is too cheap to create real inovation.

And I say that paying 24p/kWh day rate and 9p/kWh night rate and have just paid my 'winter bill' when my E7 water cylinder was bust, so £260 for that quarter.

Things are fixed now but when I calculate the total cost with meter rental and VAT, the unit rate is not often below 16p/kWh and that is using 80% night rate.

 

This is one of the problems I have with the higher FIT rates (i.e. those which give a pretty decent rate of return on investment) - it's essentially a transfer of money from those who can't afford the capital cost of a PV system to those who can. There is some justification for the idea - the private sector has a huge amount of capital available which has been unleashed to increase the uptake of PV, which is IMHO a good thing and might never have happened without subsidy support - but balancing the two is essential.

 

26 minutes ago, SteamyTea said:

Can't think what, maybe £350 million a week on the NHS.

 

Or just pay for a new sign for the side of the bus that says.

'We are robbing you'

Either works.

Link to comment
Share on other sites

13 minutes ago, JSHarris said:

Not their smartest ever move, IMHO.  It seems that every time the government decide to introduce incentivisation schemes associated with renewables or energy reduction they screw up, often very badly indeed.  It really annoys me that every scheme they introduce ends up being abused by installers who increase their charges in order to either collect the subsidy for themselves as extra profit, or to increase the price to consumers because the government have created a rigged market.

 

There is no perfect scheme, but some schemes are more perfect than others.

 

On the whole I think PV incentives (aside from them being dropped too quickly) are light years ahead of RHI and ECO, which are total clusterfucks and broken by design.

 

In the end, ST is correct, energy is too cheap and does not reflect externalities. You can see incentives as being a way of reflecting the externalities to the upside on the deemed "desirable" energy sources.

Edited by gravelld
Link to comment
Share on other sites

25 minutes ago, pdf27 said:

Umm... not really that convinced (although the inverter shutting down because the grid is limited would be one of the cases where I have no problem with it). The subsidy regime is one of the aspects which has contributed to your decision to use a heat pump for heating and resistance heat for hot water (albeit with a preheat tank from the heat pump). Over the course of the year, the net energy flow from grid to your house will be greater than if you had used the heat pump for water heating, even with the defrost issues you have, since you would only be export-limited for a small fraction of the time. The net result is that the subsidy forms a perverse incentive - it's a relatively modest impact in your case, but is still there. Most people with Immersuns or similar would have otherwise used mains gas to heat their water, and there the difference is rather bigger.

 

 

No it isn't, and never was, and I don't quite know how you reached the conclusion that the subsidy had any effect on our decision making process (it didn't at all - I wanted to DIY the install, but couldn't for warranty reasons).  It's not like we get much of a subsidy anyway - the premium we had to pay for the PV system outweighed any small subsidy that we get, and we still get paid less for energy generated than we do for energy imported, even with the combination of the FIT and export payment.  Read my blog and you will find I opted not to fit an MCS approved ASHP installation, so don't get RHI.  With PV I had no choice - I needed a warrantly, as the in-roof PV is an integral part of the roof covering, so had to have an MCS install whether I wanted it or not.  Generalising about people's motives causes offence, so it's best to check out the readily available facts before doing so.

 

25 minutes ago, pdf27 said:

This is one of the problems I have with the higher FIT rates (i.e. those which give a pretty decent rate of return on investment) - it's essentially a transfer of money from those who can't afford the capital cost of a PV system to those who can. There is some justification for the idea - the private sector has a huge amount of capital available which has been unleashed to increase the uptake of PV, which is IMHO a good thing and might never have happened without subsidy support - but balancing the two is essential.

 

Either works.

 

High FIT rates are long gone.  We don't get them and neither will anyone else now.  What does remain is the high premium payable for an MCS approved installation, as that is very definitely now an obstacle to people having systems installed.  A DIY system can be installed for around half, or less, than the cost of an MCS system, including the cost of a Part P qualified sparky to wire things up.

 

Link to comment
Share on other sites

4 minutes ago, billt said:

The "government" isn't paying you anything. The subsidy comes from other electricity consumers via the electricity companies.

 

Thanks, I didn't know that. I honestly assumed that the scheme was funded by government but administered by the power companies.

 

Just did a quick bit of research. With some rounding (and possibly ignoring the impact of Northern Ireland):

If I'm looking at the right numbers, this suggests that the cost of the FiT scheme is around 6% of the domestic electricity market.

 

I haven't got the time, energy (pardon the pun) or knowledge to dig into the impact of the payments for deemed self-consumption.

 

However, it also a fact that I export a lot of energy to the grid over the year, for which the electricity company pays me relatively little. I don't know how cheap the electricity I supply is relative to their wholesale sources (it's likely very complex to work this out accurately), but it would be interesting to know how far, if at all, this goes to mitigating the cost of the FiT scheme to other consumers. 

 

8 minutes ago, gravelld said:

In the end, ST is correct, energy is too cheap and does not reflect externalities. You can see incentives as being a way of reflecting the externalities to the upside on the deemed "desirable" energy sources.

 

I agree that energy is much too cheap, but increasing the price to better reflect the real cost would be hugely regressive. To avoid this, you'd need to bring in some sort of means-tested energy pricing system, which involves opening a planet-sized can of worms.

Link to comment
Share on other sites

21 minutes ago, jack said:

I agree that energy is much too cheap, but increasing the price to better reflect the real cost would be hugely regressive. To avoid this, you'd need to bring in some sort of means-tested energy pricing system, which involves opening a planet-sized can of worms.

 

Progressive/regressive charging normally relates to taxation. Can you explain why are you applying it to energy purchase?

Link to comment
Share on other sites

12 minutes ago, gravelld said:

Progressive/regressive charging normally relates to taxation. 

 

The term "regressive" has far wider usage than just taxation. 

 

https://dictionary.cambridge.org/dictionary/english/regressive:

 

"used to describe an economic or tax system in which there are advantages for rich people and disadvantages for poor people:

Economists generally regard sales taxes as regressive, since the poor spend a greater part of their income than the rich.
 
regressive policy/subsidy/measure Two decades of regressive policies have doubled the numbers living in poverty."

 

Link to comment
Share on other sites

Well you're right, it could apply to wider aspects than taxation, but to what extent we allow it to be is decided by policy. And if you're including purchase of goods and services which aren't provided by the state, you're on a slippery slope... are streaming services regressive? Internet access? Food purchase? Yes they are, but the alternative is also (probably, depending on your opinion) undesirable.

 

I would start by redrawing the market. Energy is massively overused in homes, there are productivity issues caused by ill health from poorly built and maintained buildings and fuel poverty caused by Craphauses. Those are the problems that need fixing, and given appropriate support to people of all means the market can then correct and we have a better longer term foundation to build upon.

Link to comment
Share on other sites

My view is that the whole concept of FIT/RHI is/was deeply flawed right from the start.

 

Looking at the very basics, the government (and everyone else) recognised that the initial barrier to entry for micro generation systems was the high capital investment needed.  It would have been relatively simple to apply a subsidy to PV panel and inverter costs, on a per watt basis, as a one-off subsidy for the capital investment, with that subsidy level being subject to review every few months.based on the volume of units sold.

 

It would have had the same impact - reducing the price of PV (or other systems) so that people would be inclined to buy them, but would have removed part of the "wealth barrier", because the scheme they did introduce only applied to those who had enough savings to buy the relatively expensive systems and be willing to accept their investment being paid back over 25 years by a subsidy. 

 

Investing the same amount of money as they did with FIT (ignoring the fact that they did this via a roundabout way by getting suppliers to actually make the payments, who then get relief from tax on those payments anyway) would, I'm sure, have had a more beneficial impact.  Those who wanted to make a relatively small investment, in return for reduced energy bills plus a small income from the sale of exported energy could have done so with a much lower capital outlay, which would have resulted in a broader range of people fitting systems.

 

It would also have removed all the rent-a-roof scammers, and the regulations could have been arranged to avoid the heavy overhead of MCS certification, by just allowing any SE to do the structural calcs and any qualified electrician to certify the wiring.  Another benefit would be to remove the ongoing overhead of running the FIT scheme for well in excess of 25 years (I hate to think what that costs).

  • Like 1
Link to comment
Share on other sites

16 minutes ago, gravelld said:

Well you're right, it could apply to wider aspects than taxation, but to what extent we allow it to be is decided by policy. And if you're including purchase of goods and services which aren't provided by the state, you're on a slippery slope... are streaming services regressive? Internet access? Food purchase? Yes they are, but the alternative is also (probably, depending on your opinion) undesirable.

 

I don't think the definition of "regressive" has anything to do with policy. Energy is a basic and essential commodity to everyone in society. Energy pricing is, today, whatever it is. Increasing its price would absolutely be regressive in the sense of making things more regressive, in exactly the same way that increasing VAT on food would be regressive. 

 

So in that sense, yes, increasing the cost of any of any basic necessity by adopting or changing a tax or subsidy system in such a way that it has a greater net impact on the poor is "regressive".

 

I also agree that the alternatives may be even worse, hence my reference to a "planet-sized can of worms".

  • Like 1
Link to comment
Share on other sites

1 hour ago, JSHarris said:

the government (and everyone else) recognised that the initial barrier to entry for micro generation systems was the high capital investment needed

I would have thought that someone, somewhere, would have pointed out that there was already a large downward trend in prices and that the UK market would not materially affect that trend.

Surely the better way would have been to tax the polluters more.  We had a carbon trading/taxation scheme in place in Europe, but that fell apart though mismanagement/fraud.

One of the problems is, especially in the UK, that if something fails first time around, it is never given a second chance.

But you have to remember that I am not a lover of subsidies or any sort, when iti comes to business it is much better to punish severely than reward mildly.

Link to comment
Share on other sites

42 minutes ago, SteamyTea said:

I would have thought that someone, somewhere, would have pointed out that there was already a large downward trend in prices and that the UK market would not materially affect that trend.

 

Spoken with the advantage of 20:20 hindsight.

 

There was no sign of even a small reduction in prices when the FIT scheme was introduced; if there had been I wouldn't have spent an eye-watering amount of money on a system which was wholly unaffordable without the FIT. 3 years later prices plummeted in an unforeseeable way.

 

Can't say I'm a fan of subsidies either; all the green subsidies have been ill-conceived and most subsidies benefit the relatively well off.

  • Like 2
Link to comment
Share on other sites

Back when the FIT was dreamt up, there was a well-meaning desire to support microgeneration from some quarters, and frankly it's hard to find a reason not to encourage it.  The benefits are many; it reduces the overall grid load, decreases grid losses, in the case of PV generates energy during the day, when commercial demand tends to be highest and it decreases the nation's carbon footprint, which apart from being a good thing to do also help meet international targets.

 

The problem is the usual one that faces government when it comes to supporting initiatives like this, it got well and truly high jacked by a few commercial interests that saw pound sounds in the form of subsidies, job creation schemes for new requirements (energy assessment, MCS accreditation, etc, etc) so the true cost was clearly going to be way higher than it needed to be from the off. 

 

When faced with any high expenditure, governments always, without fail, try to time shift that expenditure so that the bulk of it happens after the next General Election.  That's an immutable law of government, that impacts procurement in every area and results in most of the crazy and costly programmes we have, everything from PFI through to FIT and RHI, all are offset schemes, intended to make the government of the day look good without having to pay too much money up front.

 

At the time that FIT was introduced there were two problems.  PV prices were starting to fall, and as a consequence Germany was starting to complain about the lower prices of Chinese made panels and inverters (Germany being the biggest EU producer of them).  A punitive "anti-dumping" tariff was imposed on Chinese made panels, which only expires later this year.  That artificially held the price of PV up, and the predictions at the time were that PV prices would not fall very quickly (those predictions were wrong, for a host of reason, perhaps the biggest being that no one foresaw the massive expansion of PV use in China itself, as they adopted renewable generation on a massive scale).

 

The government were convinced that a subsidy was needed if the UK was going to kick-start distributed microgeneration, and so the FIT scheme was born.  I think that, in the circumstances, the government were right to use a subsidy to kick start microgeneration, they were wrong to use the insane scheme they adopted, and they compounded that by being both slow to realise the rate at which PV costs were dropping (so slow to reduce the subsidy) and by being well and truly fooled by the lobbying from those with heavily vested interests in keeping the subsidy scheme as it was.

 

Quite why governments feel the need to adopt complex and hard to manage subsidy schemes, when they know full well that they do not have the expertise in-house to either monitor or manage them, is beyond me.  It was quite clear from the enquiries into why DECC so hopelessly mismanaged the FIT scheme, that all involved were clueless, and that the relatively new industry that had sprung up to provide microgeneration schemes had many times the knowledge and understanding that DECC did (although they used that to protect their businesses, rather than support the original government objective).

 

We're seeing the same thing now with the government trying to encourage people to buy electric cars, but at least they are being a bit more sensible with that, and only offering an incentive, in the form of a grant, towards the initial purchase, and they aren't subsidising expensive, luxury electric cars now.  Had they done the same with PV, offered a grant to reduce the initial capital expenditure, then I can't help but feel that would have both cost less money and resulted in an easier to manage scheme, with no long-term commitment to continuing any subsidy.  Simply making PV systems affordable, and then agreeing that suppliers should buy excess generated electricity at a rate that is close to the mean wholesale price, would have worked, particularly if they had amended Part L1A to include a requirement for a minimum amount of renewable generation on every new home as well.

 

 

Link to comment
Share on other sites

48 minutes ago, JSHarris said:

Had they done the same with PV, offered a grant to reduce the initial capital expenditure, then I can't help but feel that would have both cost less money and resulted in an easier to manage scheme, with no long-term commitment to continuing any subsidy. 

They used to offer grants, our old mate DamonHD used it, and that strange low carbon (Nofal or Naffle or whaterever it was) scheme to install his.

That was deemed to complicated at the time too.

Edited by SteamyTea
Link to comment
Share on other sites

One positive thing on the horizon is the lifting of the EU "anti-dumping" tariff on PV that should happen at the end of September.  This should result in a price drop of around 10 to 15% for Chinese made panels, but whether that will materialise as a reduction in retail price I'm not so sure.  It should do, if some of the better known companies that import stuff direct from China already (like Navitron, ESP etc) are prepared to buy in some stock at the lower price and then sell them directly.  Not sure that I could bring myself to buy anything from Navitron, though, just because they were so very rude last time I had any dealings with them (more fool them, they lost a purchase of around £8k or so as a direct consequence).

Link to comment
Share on other sites

23 minutes ago, Nickfromwales said:

Could you elaborate on this please Jeremy?

 

In essence, as it was a new build, I wanted the whole roof to have a warranty for more than just the statutory year.  This meant that I had to select an in-roof PV supplier that offered a decent warranty, which in turn meant using an MCS accredited firm, as I couldn't find any non-MCS installers who offered both an in-roof option and a decent warranty.

 

My main concern was making sure the in-roof PV kept the water out for many years to come.  No reason why a DIY install wouldn't have been as good, it was really just for my own peace of mind.

Link to comment
Share on other sites

21 minutes ago, JSHarris said:

 

In essence, as it was a new build, I wanted the whole roof to have a warranty for more than just the statutory year.  This meant that I had to select an in-roof PV supplier that offered a decent warranty, which in turn meant using an MCS accredited firm, as I couldn't find any non-MCS installers who offered both an in-roof option and a decent warranty.

 

My main concern was making sure the in-roof PV kept the water out for many years to come.  No reason why a DIY install wouldn't have been as good, it was really just for my own peace of mind.

Ok, just curious as I wondered if that was a stipulation from MBC ( or any other TF supplier ) to maintain their own warranty. As MBC leave you rain-proof but not covered, is it right to assume their warranty stops at the felt and batten ?

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...