Solar PV Feed In Tariffs - Good or Bad?

John_Pierpoint

tut tut have we factored in building the new national grid extension to Gold Rush Cornwall, or will all those surfers mop up the new generation?

Putting solar panels on the roof is one of the quickest ways of upgrading your home's energy rating.

Martyn1981

rogerblack wrote: »

Anyone want to bet it's rather cheaper than the 90 million or so the eqivalent number of solar on roof installations would cost? (including subsidy)

Aha.
A teeny bit of googling comes up with the figure of 35 million.

Or about 90p/watt.

We need more of this sort of scheme.
Though perhaps on a slightly more modest scale.

Only speculating, but I'd have priced it closer to £50m, on the basis of 10,000 3.2kWp installs @ £5k a pop.

So £35m + annual costs v's £50m all in. Probably too close to call.

I won't take offence at your decision to do a teeny bit of googling, after all my hard work in supplying two links!

Mart.

rogerblack

Martyn1981 wrote: »

does this subtle revision finally mean you realised your mathematical/accounting error, in claiming that panels on roofs don't have the same net effect on the grid as panels in a field?

If the solar used for water heating displaces electricity for water heating, there is very limited effect.
(differences in carbon generation over the day/night cycle, may have tiny effects).

If, however, 1kWh of electricity is used to replace gas heating, the effect is not insignificant.

The starting point can't neglect the fact that the primary purpose of the FIT scheme is to reduce CO2 generation, and the panels are subsidised for this reason.

(http://help.smeasure.com/kb/faqs/what-ghg-emission-conversion-factors-are-used-in-smeasure)
CO2 generation per kWh of electricity is about 550g/kWh.
CO2 per kWh of gas is 200g/kWh.

Price paid by other bill payers for displacing 550g of carbon, if all exported - 26p/kg.

If used for heating in a domestic boiler, 275g/kWh for gas.

Net loss by using generation internally, 275g/kWh.

Other bill payers are paying you 50p/kg of CO2 you cause to be generated by not exporting.

Cardew

Martyn1981 wrote: »

As usual, you are wrong / mis-quoting again. The discussions in question revolved around the financial viability of PV systems, domestic, commercial, and farm scale. And the difficulties placed on the eventual viability of PV farms due to wholesale leccy prices being so very much lower than retail prices.

Keep up - big or small, the more the better.

Mart.

PS, I note your reference to export, now includes water heating, does this subtle revision finally mean you realised your mathematical/accounting error, in claiming that panels on roofs don't have the same net effect on the grid as panels in a field?

You have a selective memory and a complete inability to use any form of logic on this subject.

You need to get don0301 back to discuss solar as equals.

Martyn1981

rogerblack wrote: »

If the solar used for water heating displaces electricity for water heating, there is very limited effect.
(differences in carbon generation over the day/night cycle, may have tiny effects).

If, however, 1kWh of electricity is used to replace gas heating, the effect is not insignificant.

The starting point can't neglect the fact that the primary purpose of the FIT scheme is to reduce CO2 generation, and the panels are subsidised for this reason.

(http://help.smeasure.com/kb/faqs/what-ghg-emission-conversion-factors-are-used-in-smeasure)
CO2 generation per kWh of electricity is about 550g/kWh.
CO2 per kWh of gas is 200g/kWh.

Price paid by other bill payers for displacing 550g of carbon, if all exported - 26p/kg.

If used for heating in a domestic boiler, 275g/kWh for gas.

Net loss by using generation internally, 275g/kWh.

Other bill payers are paying you 50p/kg of CO2 you cause to be generated by not exporting.

Roger I agree with everything you say there, as it's both correct and logical. However, my comments relate to Cardew's long term position that PV farm's export more leccy to the grid, as he believes that 'normal' electricity consumed by householders should not be classed as export.

He fails to note, nor accept that not importing a unit (by a house with PV) is the same as exporting a unit (by a PV farm).

He then uses this false claim, to artificially boost PV farm generation by 50%, when comparing it to household generation.

So a micro-farm in a house's garden, that exports one unit to the grid, before that leccy unit is 'sucked' back in as normal demand, magically supports the grid more, than if the same unit from a roof displaces one unit of import.

Clearly in both cases, generation, consumption and 'the grid' are the same, the only difference would be that in the PV farm situation the export and import meters would both register 1 unit more - nothing more than an accounting exercise.

This is the silly argument I (and Zeup) try repeatedly to explain to him, when he keeps using it to falsely distort the benefits of roof v's farm generation.

Obviously devices such as the Immersun, will distort export, changing some of it into different forms, such as gas, oil, lpg or E7 export, and as you state have an effect on CO2 emmissions. That is why I suspect he referred to such devices today, as he has probably now accepted his mistake, but after a solid week of denial (on thread) is unwilling to admit it.

Mart.

Cardew

Martyn1981 wrote: »

He fails to note, nor accept that not importing a unit (by a house with PV) is the same as exporting a unit (by a PV farm).

He then uses this false claim, to artificially boost PV farm generation by 50%, when comparing it to household generation.

No sooner have I commented on your complete lack of logic, but you go ahead and demonstrate it once again. This you achieve with a complete lack of understanding of the points I and others have made.

My position has been consistent. If we electricity consumers have to subsidise solar PV, then it makes sense to pay smaller subsidies to large solar farms where all of the generated electricity is exported to the grid.

Instead of higher subsidies paid to house owners who don't even have export any of their electricity to the grid.

Thus for the subsidy we pay, the grid gets more electricity from solar farms than it gets from houseowner's roofs. It is a question of value for those who pay the subsidy.

To make it even easier for you to understand an analogy(albeit you didn't understand before).

If people who ate potatoes had to pay a subsidy for potatoes to be grown.

Potatoes could be grown by a farmer for a subsidy of 10p a kilo.

Or, by house owners in their back garden getting a 20p a kilo subsidy.

Which is the better value to those paying the subsidy?

Now to add insult to injury, the house owners are allowed to eat as many of those potatoes as they wish and still get exactly the same subsidy for all the potatoes they grew.

Now can you understand that - I mean really understand that.

I suspect not!

Martyn1981

Firstly, let me make the following statement:

I do not for one second, believe that you do not understand this. I believe that you only pretend to believe this maths trick (that you created) in order to further your anti-PV propaganda, and need to create division and diversion through such cheap methods.

However, I’ll explain it again (without the need to resort to potatoes, or other smokescreens), with a simple example:-

Imagine a very small grid. It has one powerstation producing 5,000kWh’s per annum, and two household customers, both of whom require 4,000kWh’s pa.

Supply falls 3,000kWh’s pa short of demand.

To meet demand there are two solutions,

Solution 1. Is to build a PV farm that will produce 3,000kWh’s pa and export all of this to the grid. The grid now has 8,000kWh’s of available supply, to meet 8,000kWh’s of demand.

Solution 2. Is to install PV on one of the house roofs (house A) producing 3,000kWh’s pa. However, 1,000kWh’s pa of generation will coincide with consumption, and be consumed on site (house A). The remaining 2,000kWh’s pa are exported, boosting the grid supply to 7,000kWh’s, which matches total demand of 7,000kWh's pa (4,000kWh’s house B, and the remaining 3,000kWh’s from house A).

As you can see (hopefully) same grid, same panels, same generation, same consumption.

If you really are struggling with this concept, then make one simple mental adjustment to your calculations, and assume that all domestic PV generation was routed out of the house, before being drawn back in – this way domestic (and of cause commercial) PV would mimic a PV farm’s role. This is of course a pointless exercise, but it might clear up any remaining misunderstandings you have.

Now, as promised, if we really have put this silly trick to bed, are you now finally willing to explain why in your PV farm argument you claimed a ratio of 2:1 on a tariff subsidy basis, rather than 1.3:1 ratio. In other words, why did you falsify the numbers and claim that the two rates were 20p and 40p, when they weren’t?

Mart.

Cardew

Not only am I 'struggling with that concept' it is laughable. We have a National Grid that takes electricity from generators and supplies it to consumers!

The situation is simple, we pay a very high subsidy for tiny systems on roofs dotted all over UK to generate electricity, and those systems receive that very high subsidy for every kWh of generated electricity, regardless of how much of that electricity they export - they can(in theory) export absolutely nothing.

A solar farm gets a lower subsidy for each kWh generated electricity and export virtually all of that electricity to the grid.

You cannot possible argue(except you will) against the fact that those of us paying the subsidy, in higher electricity bills, get better value from the solar farms - a lower subsidy for each kWh and all of it exported.

The potatoes analogy is perfectly valid except you musn't take the 10p a kilo and 20p a kilo subsidy literally - less you accuse me of falsifying the numbers. 40p/20p indeed! - you really clutch at straws.

Read back through your latest post and see if it doesn't demonstrate your complete lack of logic - time for you to send out some more PM's to your fans methinks.

P.S.
Why anti-PV propaganda? Of course I think the FIT subsidy system is a farce. Does arguing my point of view make it propaganda in your book? As least mine argument has logic, which yours is sadly lacking.

Oscargrouch

Cardew wrote: »

The situation is simple, we pay a very high subsidy for tiny systems on roofs dotted all over UK to generate electricity, and those systems receive that very high subsidy for every kWh of generated electricity, regardless of how much of that electricity they export - they can(in theory) export absolutely nothing.

A solar farm gets a lower subsidy for each kWh generated electricity and export virtually all of that electricity to the grid.

You cannot possible argue(except you will) against the fact that those of us paying the subsidy, in higher electricity bills, get better value from the solar farms - a lower subsidy for each kWh and all of it exported.

The potatoes analogy is perfectly valid except you musn't take the 10p a kilo and 20p a kilo subsidy literally - less you accuse me of falsifying the numbers. 40p/20p indeed! - you really clutch at straws.

Think you may be wrong in so many areas: The high Subsidy has now gone, it is only 20p or even less now, and keeps dropping. Even the 'wise' that invested in PV have to pay the subsidy at the same rate as you on their import (which in fact is a pittance). Your theory of "they can(in theory) export absolutely nothing"; will be history when 'smart meters' are rolled in; as the exact import/export can be calculated. Currently PV owners are assumed to use 50%, most are likely to only use 30% or less. I used 27.59% last year, so I was fiddled out of 22.41% of what I generated; even that is only at circa. £0.03p per kWh. I think you may need to study the Gov. commitment on Carbon reduction, if they do not succeed, it may cost us all much more than what you think.

I may tell you more about 'Solar Farms' & 'Rent a Roof' schemes in a later post; just to enlighten you, if I can be bothered. As the site is closing at 23:59 tonight for maintenance, I have not got the time or the patience tonight---goodnight.

John_Pierpoint

The situation is a bit like "dig for victory" in the war. The agricultural system had to be switched from meat and milk towards growing the basic carbohydrates that could no longer be imported over the U boats and paid for with money we did not have.

So the government had a two pronged attack of investing in farmers - new concrete roads all over the fens to get the food supplies out during the winter months. "Uneconomic" beat sugar. etc etc.

But at the same time ordinary householders increased their production with modest encouragement in the form of fertilisers and grain for "back yard" production of vegetables, chickens & rabbits.

Given that we need to invest in a second national grid (complete with 10% (?) power losses) it would be interesting to know the relative balances of this type of exercise last time round.

It is just a pity that nobody has explained to the EU bureaucrats that massive subsidies to support agricultural production are no longer necessary, though stimulating alternatives to fossil fuels is required.