Energy import benefits of UK Solar PV

PeterZ_2

Now that we have to import increasing amounts of gas due to North Sea gas decline and the closure of coal fired plant, what are the benefits of PV due to reduced gas imports?

I think its highly likely that in the coming years we will see huge price increases in gas. If solar PV is reducing the amount of gas burnt at the power station then its reducing our imports and helping with the trade balance.

Anyone got any thoughts or numbers to play with?

Cardew

There is much discussion on this subject in the 'Green' section of MSE.

The problem with solar PV is firstly its unpredictable generation. An array on a house can be generating 4kW one minute and a cloud can drop the output dramatically.

Unfortunately you cannot 'shut down' power stations 'instantly' to cater for this unpredictable solar output.

Secondly the period of peak consumption in UK is on a late winter afternoon, when solar is generating zilch! So no matter how much solar generation capacity in UK, we still need to have 'conventional' generating capacity in the shape of coal/gas/nuclear etc power stations to cope with that load. So solar does not lead to any reduction in our generating capacity.

Above is a simplistic explanation, there are posters on MSE who worked on the National Grid who can elaborate.

PeterZ_2

Cardew wrote: »

There is much discussion on this subject in the 'Green' section of MSE.

The problem with solar PV is firstly its unpredictable generation. An array on a house can be generating 4kW one minute and a cloud can drop the output dramatically.

Unfortunately you cannot 'shut down' power stations 'instantly' to cater for this unpredictable solar output.

Secondly the period of peak consumption in UK is on a late winter afternoon, when solar is generating zilch! So no matter how much solar generation capacity in UK, we still need to have 'conventional' generating capacity in the shape of coal/gas/nuclear etc power stations to cope with that load. So solar does not lead to any reduction in our generating capacity.

Above is a simplistic explanation, there are posters on MSE who worked on the National Grid who can elaborate.

Same old nonsense from Cardew, who once again completely missed the point.

FACT 1 - PV generates during the day, when electricity demand is high
FACT 2 - reduced demand for electricity mean less fuel needed at the power station

Less gas burnt at the power station means less gas imported. I'm trying to put a figure on the value to the UK economy of reduced gas imports.

antrobus

PeterZ wrote: »

...Less gas burnt at the power station means less gas imported. I'm trying to put a figure on the value to the UK economy of reduced gas imports.

Wouldn't you first of all have to find out where the various components of your PV solar system had been manufactured, in order to calculate the potential initial cost to the UK economy of importing them? I have no idea myself, but I wouldn't exclude the possibility that (say) the £5000 cost of importing the Chinese manufactured panels will generate an expected saving in reduced gas imports of only £2500.

PeterZ_2

antrobus wrote: »

Wouldn't you first of all have to find out where the various components of your PV solar system had been manufactured, in order to calculate the potential initial cost to the UK economy of importing them? I have no idea myself, but I wouldn't exclude the possibility that (say) the £5000 cost of importing the Chinese manufactured panels will generate an expected saving in reduced gas imports of only £2500.

Good point - Lets take a starting point of minus £5k for the cost of importing the equipment and go from there.

doughnutmachine

i read that 80% of the cost of a solar installation is imported from abroad...

rogerblack

To a pretty close approximation - 1kWh of solar will displace 1kWh of normal generation. (up to a limit, which we are not yet close to).
This won't be all gas, some of it will be reduced imports from france, some will be turned down coal, but it all helps.

As to costs, the accounting gets gnarly.

Do you include the costs of fines that would be levied due to not complying with CO2 reduction targets without solar?
If you do, then that raises the other issue of what else might have been done with the money.
For example.

I install a 4kW solar array now, and it costs me say 5K, which isn't an unreasonable price now.
The government over 20 years will pay me some 12K for this.
(Technically not the government, but...)

The value of this money if it was given to me as a lump sum now might be something like 8K. (I'm assuming the ability to borrow at the same rate as the government).

This shows the rather schitzophrenic attitude of the government.

If I install solar panels, they give me 3K. (8k-5k)

If I go through the green deal, and get insulation improvements that cost the same 5K, and save as much carbon/fuel import, they charge me 4K or so.

(Numbers fuzzy, exactly how you work this out depends on detailed calculations of future interest. )

PeterZ_2

Roger - some more good points raised, but I would like to work on the assumption that any FITs paid out stay within the UK economy. Trying to include potential CO2 fines from the EU is going to make it way too complicated. Just an aproximation will be fine, just looking to get a rough idea of the value (if any) to the UK.

Maybe its best to take a simple view and look at the percentage of UK energy that is imported and use that as a basis. I'll see if I can find some figures.

tberry6686

The amount of gas saved by solar generation is likely to be a very trivial amount. This is due to the fact that no matter how many solar panels there are there must be an operational powerstation ready to take over from them at a moments notice.

It's a well known fact that for all the wind turbines, solar panels etc in existence not one conventional power station has been closed down due to re-newables (the truth is the only renewable that currently works outside of certain deserts is Hydrothemal power and is likely to remain that way for a long time).

Martyn1981

PeterZ wrote: »

Roger - some more good points raised, but I would like to work on the assumption that any FITs paid out stay within the UK economy. Trying to include potential CO2 fines from the EU is going to make it way too complicated. Just an aproximation will be fine, just looking to get a rough idea of the value (if any) to the UK.

Maybe its best to take a simple view and look at the percentage of UK energy that is imported and use that as a basis. I'll see if I can find some figures.

Hiya Peter, obviously working out what percentage of an install is 'export' costs is always going to be tricky, but looking at retail prices on a renewables shop, the panels and inverter probably represent about 50% of the cost. Some of those costs won't be 'exported' but will be port fees in UK etc, but 50% looks good.

The other 50% will be scaffolding, mounting kit, electrical kit, labour, fees (such as MCS etc) and installer overheads then profits.

On a new build, you might be able to knock £1,000 off that £5,000 example cost, but this would then increase the export percentage.

As to gas savings, many people argued that having plants on tick over would burn just as much gas. Obviously PV is still very small in the UK, but as it grows, it's 'intermittent' impact would presumably be similar to that of wind power. Note, I'm not saying the scale of impact, rather that how PV generation and gas consumption interact, would presumably be similar to the interaction of wind and gas.

If so, then this article is quite important as it tried to show that there is a genuine correlation between wind generation and gas consumption. It's a little old, and the dates refer to 2011 (not 2012):

http://www.guardian.co.uk/environment/blog/2012/sep/26/myth-wind-turbines-carbon-emissions

"It's a myth that wind turbines don't reduce carbon emissions
Conclusive figures show that the sceptics who lobby against wind power simply have their facts wrong"

Obviously I'm concentrating on your gas reduction question, not gas plant reduction, since the role of PV is to help reduce the CO2 intensity of our generation, not to meet winter peak generation.

Mart.

Cardew

PeterZ wrote: »

Same old nonsense from Cardew, who once again completely missed the point.

FACT 1 - PV generates during the day, when electricity demand is high
FACT 2 - reduced demand for electricity mean less fuel needed at the power station

Less gas burnt at the power station means less gas imported. I'm trying to put a figure on the value to the UK economy of reduced gas imports.

Firstly, I was using an unfamiliar device to post and thought I was posting on the gas forum hence my opening remark.

Secondly I had quite forgotten your name(and posting style!) as you haven't posted using that name for a long while - welcome back.

There is nothing incorrect in my post at all - nor have I 'missed the point.' The facts are exactly as stated in post#9 above by tberry6686.