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Martyn1981

It is why (for example) a 5kwp system would not breach the domestic DNO 16amp limit.

Just a short note to anyone reading this and considering a PV install in the UK, please be careful the advice is not correct.

In the UK you need prior permission from the DNO to install a system that could (even theoretically) exceed 3.68kW export.

So if you have a split system running through a single inverter, which is limited to 3.68kW, then you are fine, regardless of the kWp of the panels.

However, if you have 2 2.5kW inverters, one for each roof and PV exceeding 3,680Wp* then you will need to seek DNO approval beforehand.

*The DNO might take into account inverter efficiences, you will need to ask, so if they are say 96% efficient, then you might be OK up to 3,833Wp, just as an example.

I should also point out that this has nothing to do with cf's. If the UK weather improved dramatically and we got twice as much generation across the year, doubling our cf to 20-22%, this would not, of course change the amount of W's peak, nor impact the 3.68kW limit. [Technically, I suppose more annual generation would probably mean more heat, which might then mean less W's at peak, but more Wh's in total.]

Please be careful, one and all.

Nicolai_Grenovski

Martyn1981 wrote: »

Just a short note to anyone reading this and considering a PV install in the UK, please be careful the advice is not correct.

In the UK you need prior permission from the DNO to install a system that could (even theoretically) exceed 3.68kW export.

So if you have a split system running through a single inverter, which is limited to 3.68kW, then you are fine, regardless of the kWp of the panels.

However, if you have 2 2.5kW inverters, one for each roof and PV exceeding 3,680Wp* then you will need to seek DNO approval beforehand.

*The DNO might take into account inverter efficiences, you will need to ask, so if they are say 96% efficient, then you might be OK up to 3,833Wp, just as an example..

Yes naturally you require DNO permission to inject power into its system.
That goes without saying - it is dealt with by the solar provider, not the consumer.

The limit of any one tail is 16 amps (hence the 3833watts limit (which at a deemed 240v at a power factor of 1 is 15.97amps - this follows standard electrical legislation.

I should also point out that this has nothing to do with cf's. If the UK weather improved dramatically and we got twice as much generation across the year, doubling our cf to 20-22%, this would not, of course change the amount of W's peak, nor impact the 3.68kW limit.

When you look at the efficiency of the designed system you are measuring its cf.
Capacity Factor is the average power generated, divided by the rated peak power of the system.
Thus, an East/West system has a lower cf than a system optimised to point to the average seasonal position of the sun (albeit it spreads what power it does produce more evenly throughout the day.
So a shallower but longer power 'curve' when plotted to the useable daylight.

[Technically, I suppose more annual generation would probably mean more heat, which might then mean less W's at peak, but more Wh's in total.]

No, sorry but that is completely wrong - whilst power output is affected by cell temperature, you're always going to be better off with an illuminated cell than one that is cooler through being less illuminated.

Nicolai_Grenovski

Martyn1981 wrote: »

Please be careful, one and all.

Yes, please resist the urge to correct via paraphrase.
There is no scientific application of semantics.

Exiled_Tyke

Nicolai_Grenovski wrote: »

Yes, please resist the urge to correct via paraphrase.
There is no scientific application of semantics.

Well there was I thinking that it was nice to read (for a change) a balanced, courteous discussion only for it to descend into pointless needling yet again.

zeupater

Nicolai_Grenovski wrote: »

..

[Technically, I suppose more annual generation would probably mean more heat, which might then mean less W's at peak, but more Wh's in total.]

No, sorry but that is completely wrong - whilst power output is affected by cell temperature, you're always going to be better off with an illuminated cell than one that is cooler through being less illuminated.

Hi All

Sorry, but I really had to have a laugh at that ... :rotfl: ... Saying "You're wrong", then effectively proving you're not!... :wall:

:idea: ... Say's it all really - don't you just love the way experts and their grasp of fundamentals tend to mesh so well ... :whistle:

HTH
Z

Martyn1981

Exiled_Tyke wrote: »

Well there was I thinking that it was nice to read (for a change) a balanced, courteous discussion only for it to descend into pointless needling yet again.

Thank you. That's why I've stopped responding, but unfortunately I can't do that now as the wrong information is being posted, which might mislead potential PV'ers.

Having been personally involved with all the research and discussions with my DNO I know the rules, which makes it difficult to ignore recent posts. I've also had a few more discussions recently with my DNO to research/double check advice that I've posted on other forums, particularly regarding plug-n-play PV systems and their legality (not!) in the UK.

The limit of any one tail is 16 amps (hence the 3833watts limit (which at a deemed 240v at a power factor of 1 is 15.97amps - this follows standard electrical legislation.

The limit is 3,680W (it was changed from 16A about 5yrs ago). It is based on 16A's at a UK nominal 230W, however as UK voltage varies, power output (wattage) would be higher at say 250V's, hence the change.

No, sorry but that is completely wrong - whilst power output is affected by cell temperature, you're always going to be better off with an illuminated cell than one that is cooler through being less illuminated.

To clarify and correct. The DNO 3,680W limit is one of power, not energy. They do not care how much PV you have nor where it faces, so long as peak output can not exceed 3.68kW. In fact during my on-site chat with my DNO they stated clearly that orientation, shading, pitch etc can not be taken into account since that would make their job next to impossible. That seems totally fair.

I personally have a 5.9kW DNO limit agreed, and the DNO confirmed I can add any amount of PV I want, but will need prior permission from them if I wish to alter the inverters (sum of 5.9kW) to one that is higher.

In a hot and sunny country 4kWp of panels will generate more than in the UK, let's say Australia at 1,400kWh-1,800kWh/kWp v's around 1,000kWh/kWp in the UK.

However, for the grid managers, they are concerned about the peak export (not annual export), which in Australia will most likely be a tad lower than in the UK, as the higher temp will reduce the peak 'W's' output, but across the year (and possibly day) increase the 'Wh's'.


So, to recap for anyone considering a PV install greater than 3.68kWp, if your inverter(s) can exceed 3.68kW output, you will need prior approval from the DNO, it is not 16A's, it is 3,680W, it is not 16 amps at 240V, it is 3,680W. And cf has absolutely nothing to do with it.

Martyn1981

PV comeback, perhaps?

Housing developers in need of re-education over solar and storage

New build housing developers are in need of a re-education if they are to realise the benefits that solar and storage installations pose for their projects.

Rooftop solar PV was widely expected to receive a boon from the new build housing industry via the government’s zero carbon homes initiative, which would have mandated every new housing development to generate as much power via on-site renewables as possible from 2016, were it not abruptly cancelled the year before.

The policy decision, made at a time of swinging cuts to renewables, was widely pilloried and decried as “the worst thing the Tories have done” by former energy secretary Sir Ed Davey at an industry event later that year.

Solar, and particularly storage, are commonly seen as expensive additions to a house building programme but offer greater returns than other technologies.

Jardine paid particular attention to the nascent battery storage market which he said was suffering more severely than solar PV as a result of costs. However, he added that this barrier could easily be supplanted by direct legislation covering new build housing developments, adding battery storage as a necessity for planning consent.

This could come under the need to offer grid balancing services as a result of housing developments adding to strains and stresses on the local distribution network, with Merton Council understood to be considering something similar.

Martyn1981

Solar costs to fall further, powering global demand - Irena

SINGAPORE, Oct 23 (Reuters) - Solar power costs will fall by another 60 percent over the next decade giving an already booming market another boost, the head of the International Renewable Energy Agency (Irena) said on Monday.

Irena also expects the cost of batteries, key to back up a technology that relies on daytime, to fall by 60 percent to 70 percent in the next decade.

Martyn1981

World solar installs are closing in on the 100GWp milestone, maybe this year, maybe next year.

Global solar market to grow 30% and reach close to 100 GW this year, says Bernreuter Research

The global solar market is set to end 2017 some 95 GW larger than when it began, according to German analyst firm Bernreuter Research.

This record growth could even hit triple figures going by polysilicon supply data, which is enough to push global production of crystalline silicon cells to 100 GW, the report adds.

China’s solar PV market is on track to reach 52 GW of new installations this year, with the U.S. way back in second place with 12.5 GW of new solar, followed by India (9 GW), Japan (a mere 5.8 GW), Germany (2.2 GW) and Brazil (1.3 GW). Australia, Chile, Turkey and South Korea will all be GW-scale markets this year, Bernreuter Research said.

Martyn1981

Despite Trump Tantrums, Growth Of Solar Power Strongest In Red States & Republicans Love Solar

Donald Trump’s desire to pollute America’s skies with millions of tons of poisonous gases from coal-fired generating plants is running into a problem. It costs too much money. In many so-called red states that voted for Trump, the demand for solar power is rising and creating jobs faster than any other sector of the economy, according to research by Greentech Media.

“Climate change has never come up in any discussion about why we would do a project,” said Matt Beasley, chief marketing officer for Silicon Ranch Corp, a solar developer based in Nashville, Tennessee. “It is always about the economics.”

The coal industry likes to complain that subsidies for renewable energy are unfair and a waste of taxpayer money. But in fact they have done precisely what they were intended to do — support new technology that is vitally important to the nation until prices fall far enough to make it more broadly viable without incentives.

And there is another side to the story. Those incentives have driven a surge in jobs in the renewable energy industry. Today, more than 300,000 Americans are employed in the renewable energy sector — 6 times the number working in the coal industry.