UK diy (uk.d-i-y) For the discussion of all topics related to diy (do-it-yourself) in the UK. All levels of experience and proficency are welcome to join in to ask questions or offer solutions.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 86
Default Realistic claims for solar pv

How realistic are the manufacturers claims for energy produced by their solar pv panels. If they claim 2kw howlikel is this to be true/realistic ?
  #6   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 6,896
Default Realistic claims for solar pv

In article , Martin Brown '''newspam'''@ne
zumi.demon.co.uk scribeth thus
On 30/04/2019 08:37, The Natural Philosopher wrote:
On 30/04/2019 08:15, wrote:
How realistic are the manufacturers claims for energy produced by
their solar pv panels. If they claim 2kw howlikel is this to be
true/realistic ?

realistic at midday in June.


It is better than you might think in winter direct sunlight since to
some extend the cold makes the panel a bit more efficient.

You can also push solar panels a bit harder at the risk of cooking them
by adding a couple of mirrors either side. Some fold out portable
battery chargers work that way.

Average about 20W


Pessimist! The usual figure for the UK is about 900kWhr per 1kW peak of
PV panel which in ballpark terms is about 100W average (taking a year as
9000hr). The further north you go the worse it gets.

Even so I am inclined to think that solar is a bit of a waste of time in
the UK since it isn't really sunny enough to be worthwhile. At lower
much sunnier latitudes where peak solar power generation coincides with
peak aircon demand then having an extra layer on the roof providing
shade and solar PV power serves a useful purpose.

A lot of UK solar generated electricity is immediately dumped into the
homes immersion heater because of FIT market distortions. You get paid
for half of what you generate irrespective of what you do with it!


Well right now. 30/4 at 12:14 not that sunny today Gridwatch is
reporting 6.31 GW 16% which is a fair chunk of the UK demand..

--
Tony Sayer


Man is least himself when he talks in his own person.

Give him a keyboard, and he will reveal himself.


  #7   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 7,829
Default Realistic claims for solar pv

tony sayer wrote:

today Gridwatch is reporting 6.31 GW


From 13GW of installed PV capacity.
  #8   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 435
Default Realistic claims for solar pv

On 30/04/2019 12:15, tony sayer wrote:


Well right now. 30/4 at 12:14 not that sunny today Gridwatch is
reporting 6.31 GW 16% which is a fair chunk of the UK demand..



At 12:14...

The problem with solar in the UK is that it doesn't generate power when
we need it most.

I'm still having mega problems understanding why we can't deliver
nuclear more cost effectively. It seem we should be able to do that and
keep both TNP and the global warming crowd happy. A reliable base load
give us much more scope for load balancing via smart devices.
  #9   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 229
Default Realistic claims for solar pv

On 30/04/2019 11:14, Martin Brown wrote:
Pessimist! The usual figure for the UK is about 900kWhr per 1kW peak of PV panel which in ballpark terms is about 100W average (taking a year as 9000hr). The further north you go the worse it gets.

Even so I am inclined to think that solar is a bit of a waste of time in the UK since it isn't really sunny enough to be worthwhile. At lower much sunnier latitudes where peak solar power generation coincides with peak aircon demand then having an extra layer on the roof providing shade and solar PV power serves a useful purpose.


Well it's only worth-while because of the very generous subsidy for those of us who got in early, though the price of solar panels has of course dropped a lot since so I don't know whether it's still worth-while.

In our case the predicted outputs were pretty accurate. We've had a 4kW set of panels on our roof since 2011 and the output each year has been at least slightly above the predictions. No real sign of ageing so far - last year was our best year overall. I just noticed the other day that near mid-day we were getting the full 4kW while the sun was out, which doesn't happen much in winter for obvious reasons. So I'm a satisfied owner so far.


--
Clive Page
  #10   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 229
Default Realistic claims for solar pv

On 30/04/2019 11:34, Tim Lamb wrote:
how much panel do you need for Hertfordshire sunshine May to October?
Hot weather conveniently requires more water which, last summer, was around 600litres/day at a head of around 5m.

My mathmatical capabilities do not stretch to this sort of problem:-)


There are quite a few programs around that predict average results, but you need to give them lots of information about your location, the azimuth and elevation of the panels, etc.


--
Clive Page


  #11   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 1,449
Default Realistic claims for solar pv

On 30/04/2019 11:34, Tim Lamb wrote:
In message , John
Rumm writes
On 30/04/2019 08:15, wrote:

How realistic are the manufacturers claims for energy produced by
their solar pv panels. If they claim 2kw howlikel is this to be
true/realistic ?


Its likely to be a true reflection of the maximum power delivery of
the panel when in full midday sun in the summer.

In peak summer you might get a load factor as hight as 20% in the uk.
In the winter it will be down in low single digits. Averaged across
the year its usually estimated to around the range of 10% - 12%. Also
peak delivery never aligns with peak demand.


Hmm.. My grazing tenant is considering solar PV panels for an unattended
cattle watering set up.
12V bilge pumps seem readily available and adequate for the head and
flow required. Lead acid battery not a problem but...
how much panel do you need for Hertfordshire sunshine May to October?


It might be OK over that period with something like a 300W PV panel to
guard against several cloudy days in succession. The main worry will be
people nicking it - even the batteries grow legs sometimes

Hot weather conveniently requires more water which, last summer, was
around 600litres/day at a head of around 5m.

My mathmatical capabilities do not stretch to this sort of problem:-)


mgh = 600kg x 10ms^-2 x 5m = 3000kJ needed each day

Roughly 8h daylight and 3600s in an hour = 29000s so in theory a 100W
panel would just be able to keep up if it was sunny every day but allow
at least twice that and you will need a charge controller too.

Every time I have tried to do solar powered irrigation (but on a
slightly smaller scale) lugging a heavy SLA battery out to the field and
taking the old one away to recharge has won hands down. Solar panels
are a bit cheaper now but I doubt if it is truly worthwhile. OTOH if he
has a solar panel just lying around it would extend the period between
having to manhandle to battery and recharge it at home.

I only needed a 3m head of water and 100L delivered daily.

--
Regards,
Martin Brown
  #13   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 1,449
Default Realistic claims for solar pv

On 30/04/2019 14:01, Tim Streater wrote:
In article , Clive Page
wrote:

Well it's only worth-while because of the very generous subsidy for
those of
us who got in early ...


Meaning that it was never really worthwhile. Subsidies are always a bad
idea as they hide the true cost of something.


It might or might not be worthwhile. You need to get some early adopters
on board if the mass production cycle is ever to get off the ground.

I don't think the economics for solar PV stack up particularly well in
the UK - we don't get enough sunshine and when we do in summer there is
less not more demand for electricity. Solar thermal is better but also a
bit borderline and isn't subsided in the UK so hardly anyone does it.

OTOH when thin film perovskite PV comes of age it might even be viable
here if it drops the price per 1kW peak by an order of magnitude.

https://physicsworld.com/a/caffeine-...e-solar-cells/

They have reached about 20% efficiency and are thermally stable now
(although it is still a bit borderline).

--
Regards,
Martin Brown
  #14   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 8,019
Default Realistic claims for solar pv

On 30/04/2019 13:11, Martin Brown wrote:
On 30/04/2019 11:34, Tim Lamb wrote:
In message , John
Rumm writes
On 30/04/2019 08:15, wrote:

How realistic are the manufacturers claims for energy produced by
their solar pv panels. If they claim 2kw howlikel is this to be
true/realistic ?

Its likely to be a true reflection of the maximum power delivery of
the panel when in full midday sun in the summer.

In peak summer you might get a load factor as hight as 20% in the uk.
In the winter it will be down in low single digits. Averaged across
the year its usually estimated to around the range of 10% - 12%. Also
peak delivery never aligns with peak demand.


Hmm.. My grazing tenant is considering solar PV panels for an
unattended cattle watering set up.
12V bilge pumps seem readily available and adequate for the head and
flow required. Lead acid battery not a problem but...
how much panel do you need for Hertfordshire sunshine May to October?


It might be OK over that period with something like a 300W PV panel to
guard against several cloudy days in succession. The main worry will be
people nicking it - even the batteries grow legs sometimes

Hot weather conveniently requires more water which, last summer, was
around 600litres/day at a head of around 5m.

My mathmatical capabilities do not stretch to this sort of problem:-)


mgh = 600kg x 10ms^-2 x 5m = 3000kJ needed each day

Roughly 8h daylight and 3600s in an hour = 29000s so in theory a 100W
panel would just be able to keep up if it was sunny every day but allow
at least twice that and you will need a charge controller too.

Every time I have tried to do solar powered irrigation (but on a
slightly smaller scale) lugging a heavy SLA battery out to the field and
taking the old one away to recharge has won hands down. Solar panels are
a bit cheaper now but I doubt if it is truly worthwhile. OTOH if he has
a solar panel just lying around it would extend the period between
having to manhandle to battery and recharge it at home.

I only needed a 3m head of water and 100L delivered daily.

Some years ago I tried to use solar lighting in winter for a small
stables. Admittedly not with a very big panel. Not very much light is
needed in the winter, but it still was a complete failure. Now, like
Martin I manage fine with a SLA swapped out every week or so.
  #15   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 25,191
Default Realistic claims for solar pv

On 30/04/2019 11:34, Tim Lamb wrote:
In message , John
Rumm writes
On 30/04/2019 08:15, wrote:

How realistic are the manufacturers claims for energy produced by
their solar pv panels. If they claim 2kw howlikel is this to be
true/realistic ?


Its likely to be a true reflection of the maximum power delivery of
the panel when in full midday sun in the summer.

In peak summer you might get a load factor as hight as 20% in the uk.
In the winter it will be down in low single digits. Averaged across
the year its usually estimated to around the range of 10% - 12%. Also
peak delivery never aligns with peak demand.


Hmm.. My grazing tenant is considering solar PV panels for an unattended
cattle watering set up.
12V bilge pumps seem readily available and adequate for the head and
flow required. Lead acid battery not a problem but...


how much panel do you need for Hertfordshire sunshine May to October?
Hot weather conveniently requires more water which, last summer, was
around 600litres/day at a head of around 5m.


OK this is entirely guesswork, so make what you want of it...

If we work it out from the work required for that lift of water... So
Force x Distance = 600 x 9.8 x 5 = ~ 30kJ of energy.

Now that ignores the losses associated with the motor, pump, and battery
cycling etc. So let's make a few wild stabs... say 60% for the motor,
80% for the battery charge cycle. Pump efficiency is harder to call -
could be 50 to 70% for a smaller one. Lets go with 60%.

so we could do 30,000 / ( 0.6 x 0.8 x 0.6 ) = ~105kJ Energy input
required from the panels.

Let's say a typical roof top sized panel can give approx 250W peak.
That's perhaps 1.2 kWh per day in summer (20% load factor). 1.2kWh in J
is 4.3 MJ. In winter is could be 0.18 kWh (3% load factor) or ~650kJ.

That sounds like it ought to be plenty, although the variation from
cloud cover can be significant - so some days you may only get a tenth
of that - so you would still be relying on the battery to provide
potentially several days worth of support worst case in the winter. (and
if you have snow cover, then all bets are off!)




--
Cheers,

John.

/================================================== ===============\
| Internode Ltd -
http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/


  #16   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 43,017
Default Realistic claims for solar pv

In article ,
Andy Burns wrote:
tony sayer wrote:


today Gridwatch is reporting 6.31 GW


From 13GW of installed PV capacity.


But the nuclear lot want a power station running flat out all day every
day.

--
*Nothing is foolproof to a sufficiently talented fool*

Dave Plowman London SW
To e-mail, change noise into sound.
  #17   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 43,017
Default Realistic claims for solar pv

In article ,
Pancho wrote:
The problem with solar in the UK is that it doesn't generate power when
we need it most.


Then you adjust the output from the generators that don't come from solar?

After all, no generator has a constant load 24/7.

--
*A 'jiffy' is an actual unit of time for 1/100th of a second.

Dave Plowman London SW
To e-mail, change noise into sound.
  #18   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 43,017
Default Realistic claims for solar pv

In article ,
Tim Streater wrote:
In article , Clive Page
wrote:


Well it's only worth-while because of the very generous subsidy for
those of us who got in early ...


Meaning that it was never really worthwhile. Subsidies are always a bad
idea as they hide the true cost of something.


Thus spake a true Tory. Except where that subsidy applies to him, of
course.

--
*INDECISION is the key to FLEXIBILITY *

Dave Plowman London SW
To e-mail, change noise into sound.
  #19   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 1,449
Default Realistic claims for solar pv

On 30/04/2019 13:31, newshound wrote:

Some years ago I tried to use solar lighting in winter for a small
stables. Admittedly not with a very big panel. Not very much light is
needed in the winter, but it still was a complete failure. Now, like
Martin I manage fine with a SLA swapped out every week or so.


At a stables if you wanted then wind power isn't too bad and you can get
300-500W units intended for topping off batteries in sailing boats.

Solar in winter is pretty hopeless. There are bunch of solar powered
active radar "please go round the dangerous bend" signs round here which
kill their batteries stone dead every winter. In summer they are in fine
fettle all day but on a frosty winters morning they are useless and they
typically fail about two hours after sunset in mid-winter.

--
Regards,
Martin Brown
  #20   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 10,998
Default Realistic claims for solar pv

2KW over how much of the hours in a year on average, its not a lot is it?

Brian

--
----- --
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
wrote in message
...
How realistic are the manufacturers claims for energy produced by their
solar pv panels. If they claim 2kw howlikel is this to be true/realistic ?





  #21   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 10,998
Default Realistic claims for solar pv

A friend has those water panels on her roof and has told me it saves a lot
of money on bills for heating water. I guess its lower tech though and lets
face it many like the idea of gadgetry!

Brian

--
----- --
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"Martin Brown" wrote in message
...
On 30/04/2019 08:37, The Natural Philosopher wrote:
On 30/04/2019 08:15,
wrote:
How realistic are the manufacturers claims for energy produced by their
solar pv panels. If they claim 2kw howlikel is this to be true/realistic
?

realistic at midday in June.


It is better than you might think in winter direct sunlight since to some
extend the cold makes the panel a bit more efficient.

You can also push solar panels a bit harder at the risk of cooking them by
adding a couple of mirrors either side. Some fold out portable battery
chargers work that way.

Average about 20W


Pessimist! The usual figure for the UK is about 900kWhr per 1kW peak of PV
panel which in ballpark terms is about 100W average (taking a year as
9000hr). The further north you go the worse it gets.

Even so I am inclined to think that solar is a bit of a waste of time in
the UK since it isn't really sunny enough to be worthwhile. At lower much
sunnier latitudes where peak solar power generation coincides with peak
aircon demand then having an extra layer on the roof providing shade and
solar PV power serves a useful purpose.

A lot of UK solar generated electricity is immediately dumped into the
homes immersion heater because of FIT market distortions. You get paid for
half of what you generate irrespective of what you do with it!

--
Regards,
Martin Brown



  #22   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 7,829
Default Realistic claims for solar pv

Dave Plowman wrote:

Andy Burns wrote:

tony sayer wrote:


today Gridwatch is reporting 6.31 GW


From 13GW of installed PV capacity.


But the nuclear lot want a power station running flat out all day every
day.


Is there anything wrong with maximising output?



  #23   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 6,938
Default Realistic claims for solar pv

In message , Martin Brown
writes
On 30/04/2019 11:34, Tim Lamb wrote:
In message , John
Rumm writes
On 30/04/2019 08:15, wrote:

How realistic are the manufacturers claims for energy produced by
their solar pv panels. If they claim 2kw howlikel is this to be
true/realistic ?

Its likely to be a true reflection of the maximum power delivery of
the panel when in full midday sun in the summer.

In peak summer you might get a load factor as hight as 20% in the
uk. In the winter it will be down in low single digits. Averaged
across the year its usually estimated to around the range of 10% -
12%. Also peak delivery never aligns with peak demand.

Hmm.. My grazing tenant is considering solar PV panels for an
unattended cattle watering set up.
12V bilge pumps seem readily available and adequate for the head and
flow required. Lead acid battery not a problem but...
how much panel do you need for Hertfordshire sunshine May to October?


It might be OK over that period with something like a 300W PV panel to
guard against several cloudy days in succession. The main worry will be
people nicking it - even the batteries grow legs sometimes

:-) 500m from the nearest highway. Trees grow along river banks so the
panel would probably go on the top of a 12 or 18ft. scaffold pole.
The battery/controller could be in a padlocked cabinet. I suppose some
sort of time delay would be required as a float over pressure switch
would reset as soon as the water had fed back through the pump. Non
return valve?

Hot weather conveniently requires more water which, last summer, was
around 600litres/day at a head of around 5m.
My mathmatical capabilities do not stretch to this sort of
problem:-)


mgh = 600kg x 10ms^-2 x 5m = 3000kJ needed each day

Roughly 8h daylight and 3600s in an hour = 29000s so in theory a 100W
panel would just be able to keep up if it was sunny every day but allow
at least twice that and you will need a charge controller too.

I suppose we need to consider pump motor efficiency.

Every time I have tried to do solar powered irrigation (but on a
slightly smaller scale) lugging a heavy SLA battery out to the field
and taking the old one away to recharge has won hands down. Solar
panels are a bit cheaper now but I doubt if it is truly worthwhile.
OTOH if he has a solar panel just lying around it would extend the
period between having to manhandle to battery and recharge it at home.


This is likely to be an annual requirement and the cost spread over
several years. It might be better to find a commercially available kit.

I only needed a 3m head of water and 100L delivered daily.


Hmm.. they could drink from the river if the general public had the
integrity to keep themselves and their dogs on the footpath.

Thanks


--
Tim Lamb
  #24   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 6,938
Default Realistic claims for solar pv

In message , John
Rumm writes
On 30/04/2019 11:34, Tim Lamb wrote:
In message , John
Rumm writes
On 30/04/2019 08:15, wrote:

How realistic are the manufacturers claims for energy produced by
their solar pv panels. If they claim 2kw howlikel is this to be
true/realistic ?

Its likely to be a true reflection of the maximum power delivery of
the panel when in full midday sun in the summer.

In peak summer you might get a load factor as hight as 20% in the
uk. In the winter it will be down in low single digits. Averaged
across the year its usually estimated to around the range of 10% -
12%. Also peak delivery never aligns with peak demand.

Hmm.. My grazing tenant is considering solar PV panels for an
unattended cattle watering set up.
12V bilge pumps seem readily available and adequate for the head and
flow required. Lead acid battery not a problem but...


how much panel do you need for Hertfordshire sunshine May to October?
Hot weather conveniently requires more water which, last summer, was
around 600litres/day at a head of around 5m.


OK this is entirely guesswork, so make what you want of it...

If we work it out from the work required for that lift of water... So
Force x Distance = 600 x 9.8 x 5 = ~ 30kJ of energy.

Now that ignores the losses associated with the motor, pump, and
battery cycling etc. So let's make a few wild stabs... say 60% for the
motor, 80% for the battery charge cycle. Pump efficiency is harder to
call - could be 50 to 70% for a smaller one. Lets go with 60%.

so we could do 30,000 / ( 0.6 x 0.8 x 0.6 ) = ~105kJ Energy input
required from the panels.

Let's say a typical roof top sized panel can give approx 250W peak.
That's perhaps 1.2 kWh per day in summer (20% load factor). 1.2kWh in J
is 4.3 MJ. In winter is could be 0.18 kWh (3% load factor) or ~650kJ.

That sounds like it ought to be plenty, although the variation from
cloud cover can be significant - so some days you may only get a tenth
of that - so you would still be relying on the battery to provide
potentially several days worth of support worst case in the winter.
(and if you have snow cover, then all bets are off!)


May to October only luckily. Last I heard, he has not yet bought the
cattle!

Looking at physical size... roughly 1.6x1.0m bit big to wave about on a
single scaffold pole.

Thanks for the maths!

--
Tim Lamb
  #25   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 435
Default Realistic claims for solar pv

On 30/04/2019 14:29, Jethro_uk wrote:
On Tue, 30 Apr 2019 12:28:13 +0100, Pancho wrote:

The problem with solar in the UK is that it doesn't generate power when
we need it most.


That's if you are obsessed about PV solar (which conveniently is also the
only solar you can sell to the grid).

Now if it was a case about being *serious* about solar, rather than a
greenwashed ponzi scheme, you'd be using solar panels to directly heat
water and then keep that stored in your hot tank for used whenever - thus
reducing your gas/electric consumption.

The point is in the UK we use most energy in the winter.

So yes piping hot water in the summer. I don't know about you but I
spend very little on hot water.

Solar power is an excellent idea, but not in the UK.

The point I find irritating is that I'm not seeing sensible energy
policy from anyone important.

A bit like Brexit, politicians would rather twiddle their thumbs than
make a good long term decision that would cause problems for them in the
short term.



  #26   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 3,080
Default Realistic claims for solar pv

On 30/04/2019 14:33, Jethro_uk wrote:
On Tue, 30 Apr 2019 14:07:53 +0100, Brian Gaff wrote:

A friend has those water panels on her roof and has told me it saves a
lot of money on bills for heating water. I guess its lower tech though
and lets face it many like the idea of gadgetry!


I think it's quite high tech, if you are using the vacuum tubey things

My primary concerns are about getting what must be quite a weight of
water onto the roof, and the potential for burst pipes. Although I guess
if your roof is doing it's job, a leaky setup should be no worry.


There's not much weight - at least with the systems that I looked into.
The tubes contain little water and there is a separate insulated tank,
which can be inside.

A small pump pushes water from the bottom of the tank, into the bottom
of the collectors and it returns to the tank from the top. The small
volume, low flow, lets the water get very hot before returning.
The pump flow can be automatically varied to give slower flow when there
is less sunlight and so maintain a high return temperature.

When there is insufficient sunlight, the pump stops and the water drains
back down to the tank (preventing freezing in the tubes). The pump can
also be stopped if the tank is getting too hot to prevent boiling in the
tubes.

I looked into buying the bits separately and making my own control
system. I did come up with a simple control circuit and software design
when I was looking into it, but I don't think I kept it when I didn't
take things any further.

SteveW
  #27   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 1,681
Default Realistic claims for solar pv

On 30/04/2019 15:01, Tim Lamb wrote:

Looking at physical size... roughly 1.6x1.0m bit big to wave about on a
single scaffold pole.

An urban dweller asks...

If the PV is within the field might the cows decide to test its support
as a scratching post?

--
Robin
reply-to address is (intended to be) valid
  #28   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 43,017
Default Realistic claims for solar pv

In article ,
Andy Burns wrote:
Dave Plowman wrote:


Andy Burns wrote:

tony sayer wrote:


today Gridwatch is reporting 6.31 GW


From 13GW of installed PV capacity.


But the nuclear lot want a power station running flat out all day every
day.


Is there anything wrong with maximising output?


There would be if it is wasted?

--
*24 hours in a day ... 24 beers in a case ... coincidence? *

Dave Plowman London SW
To e-mail, change noise into sound.
  #29   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 25,191
Default Realistic claims for solar pv

On 30/04/2019 15:01, Tim Lamb wrote:

May to October only luckily. Last I heard, he has not yet bought the
cattle!

Looking at physical size... roughly 1.6x1.0m bit big to wave about on a
single scaffold pole.


If you only need summer, then a quarter sized panel would likely do it
based on those figures.



--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/
  #30   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 25,191
Default Realistic claims for solar pv

On 30/04/2019 14:04, Brian Gaff wrote:

2KW over how much of the hours in a year on average, its not a lot is it?


A notional 2kW is probably something like 8 full sized panels. Seems a
bit excessive for a water trough.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/


  #31   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 25,191
Default Realistic claims for solar pv

On 30/04/2019 13:46, Dave Plowman (News) wrote:
In article ,
Pancho wrote:
The problem with solar in the UK is that it doesn't generate power when
we need it most.


Then you adjust the output from the generators that don't come from solar?

After all, no generator has a constant load 24/7.


Which basically means that all solar farms produce 80% (at best) of
their installed capacity from gas, and wind farms at least 50%. So if
you want "zero" net carbon, then neither is much use unless you can find
a way of storing 7TWh of energy!


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/
  #32   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 25,191
Default Realistic claims for solar pv

On 30/04/2019 15:01, Pancho wrote:
On 30/04/2019 14:29, Jethro_uk wrote:
On Tue, 30 Apr 2019 12:28:13 +0100, Pancho wrote:

The problem with solar in the UK is that it doesn't generate power when
we need it most.


That's if you are obsessed about PV solar (which conveniently is also the
only solar you can sell to the grid).

Now if it was a case about being *serious* about solar, rather than a
greenwashed ponzi scheme, you'd be using solar panels to directly heat
water and then keep that stored in your hot tank for used whenever - thus
reducing your gas/electric consumption.

The point is in the UK we use most energy in the winter.

So yes piping hot water in the summer. I don't know about you but I
spend very little on hot water.


Even if you use 100L every day of the year, that usually only works out
at under £150/year in gas... That kind of throws many of these multi
thousand pound schemes for solar hot water into context.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/
  #33   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 1,449
Default Realistic claims for solar pv

On 30/04/2019 15:34, Robin wrote:
On 30/04/2019 15:01, Tim Lamb wrote:

Looking at physical size... roughly 1.6x1.0m bit big to wave about on
a single scaffold pole.

An urban dweller asks...

If the PV is within the field might the cows decide to test its support
as a scratching post?


More or less guaranteed - that and trying to push it over. At least
there is nothing tempting and green about it for them to try and eat!

But they will try to eat any kind of loose cable they can see too.

They like scratching themselves on my fence for similar reasons.

--
Regards,
Martin Brown
  #34   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 25,191
Default Realistic claims for solar pv

On 30/04/2019 13:49, Dave Plowman (News) wrote:
In article ,
Tim Streater wrote:
In article , Clive Page
wrote:


Well it's only worth-while because of the very generous subsidy for
those of us who got in early ...


Meaning that it was never really worthwhile. Subsidies are always a bad
idea as they hide the true cost of something.


Thus spake a true Tory. Except where that subsidy applies to him, of
course.


Even true tory's can understand basic economics... subsidy can be
worthwhile when it promotes a behaviour that contributes to a common
good. Much like taxation can be be use to fold the costs of
externalities back into any practice where they are currently avoided.
That forces the true cost of an activity back onto those responsible for
it, and restores more realistic market forces.

Those that promote subsidy of renewable energy generation will argue
that its an industry that is new and hence needs support to reach
maturity (an argument wearing thin IMHO), and that there is a common
good being achieved from the production of low carbon energy.

There are major flaws in the argument that stem from the fact that we
currently have no practical use for intermittent energy sources. Hence
the delivery of it must be forced to become a continuous. Either the
producer of the energy must provide their own storage, or they rely on
existing flexible generation capacity elsewhere in the grid to make up
the shortfalls. Currently a massive externality the producer is not
having to meet. To add insult to injury, most of that flexible
generation capacity will be gas powered. So currently, by having grid
connected solar, you just lock in a requirement for gas generation which
seems to go against much of its whole stated purpose.



--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/
  #35   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 40,893
Default Realistic claims for solar pv

wrote

How realistic are the manufacturers claims for energy produced by their
solar pv panels. If they claim 2kw howlikel is this to be true/realistic ?


Depends on where you put the panel, whether it tracks,
and how much cloud you get etc and how far from the
equator you install it. As usual, its normally the best
you can ever get in the best conditions.



  #36   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 601
Default Realistic claims for solar pv

John Rumm wrote:
On 30/04/2019 15:01, Tim Lamb wrote:

May to October only luckily. Last I heard, he has not yet bought the
cattle!

Looking at physical size... roughly 1.6x1.0m bit big to wave about on a
single scaffold pole.


If you only need summer, then a quarter sized panel would likely do it
based on those figures.




I use a 40w panel to run a Oase Solar 700 pond pump, both are now around 10
years old.
On full chat according to the makers figures it will shift 700L an hour
using 8watts but that would be max 2m head .
From about now to the September in conjunction with an 80 amp hour leisure
battery it ran the water feature for quite a few hours a day and some pond
lights till about 11pm till a time switch turned them off but there wasnt
much reserve if there were some cloudy or rainy days.
Later I installed a relay coupled to one of those tiny battery charging
panels so when the conditions allowed for some solar generation it closed
the circuit from the pump to the battery .That stopped the pump flattening
the battery, the solar charge controller would have switched it off
eventually it I didnt want it to go that low.
From about October to May the charge controller took more power than was
being generated so
the system got mothballed for the winter.
If I was doing it again I would definitely go for a larger panel as they
are much cheaper relatively than when I purchased mine.
As it I have since got mains to that area of the garden and the battery
failed a while back so I have removed the charge controller and battery and
the panel is now connected directly to pump.
Sun comes out , Water feature runs.


There are quite a few solar pond pumps systems advertised , the Oase pump
one was quite expensive 10 years ago and many of the complete systems
advertised now are a lot cheaper. I suspect I could pee more than most of
them.
For reliability and to work it will not be cheap.


GH







  #37   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 6,938
Default Realistic claims for solar pv

In message , Robin
writes
On 30/04/2019 15:01, Tim Lamb wrote:
Looking at physical size... roughly 1.6x1.0m bit big to wave about
on a single scaffold pole.

An urban dweller asks...

If the PV is within the field might the cows decide to test its support
as a scratching post?


Very likely. If they get the frequency correct we could have a useful
sine wave:-)


--
Tim Lamb
  #38   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 40,893
Default Realistic claims for solar pv



"Pancho" wrote in message
...
On 30/04/2019 12:15, tony sayer wrote:


Well right now. 30/4 at 12:14 not that sunny today Gridwatch is
reporting 6.31 GW 16% which is a fair chunk of the UK demand..



At 12:14...

The problem with solar in the UK is that it doesn't generate power when we
need it most.


I'm still having mega problems understanding why we can't deliver nuclear
more cost effectively.


Basically because only the french ever did them in much
volume and even they are now stuffing it up and doing
it much more expensively than they used to.

China is doing them cheaply but unsurprisingly
no one is too keen on taking a chance with theirs.

It seem we should be able to do that and keep both TNP and the global
warming crowd happy.


But not the panic merchants who hate nukes.

A reliable base load give us much more scope for load balancing via smart
devices.


Yes, particularly in the first world that already has nuclear weapons.

  #39   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 9,066
Default Realistic claims for solar pv

On Tuesday, 30 April 2019 08:15:08 UTC+1, wrote:
How realistic are the manufacturers claims for energy produced by their solar pv panels. If they claim 2kw how likel is this to be true/realistic ?


I have only seen my PV panels hit rated output only rarely and only for a short period.

The KWp is only achieved when the sky is totally clear, the weather is cold and the sunlight is @ 90deg to the panel
I have 8Kw of PV, generates just under 8Mwh/year.
It all depends on orientation and shading (if any).
My situation is almost ideal.

They deteriorate as they age. (1%/year allegedly)
  #40   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 9,066
Default Realistic claims for solar pv

On Tuesday, 30 April 2019 12:28:16 UTC+1, Pancho wrote:
On 30/04/2019 12:15, tony sayer wrote:


Well right now. 30/4 at 12:14 not that sunny today Gridwatch is
reporting 6.31 GW 16% which is a fair chunk of the UK demand..



At 12:14...

The problem with solar in the UK is that it doesn't generate power when
we need it most.

I'm still having mega problems understanding why we can't deliver
nuclear more cost effectively. It seem we should be able to do that and
keep both TNP and the global warming crowd happy. A reliable base load
give us much more scope for load balancing via smart devices.


Nobody has a viable/economic solution to dispose of the nuclear waste.
Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Suspiciously high and random solar water/pv claims at an Enviro Home showhouse. Jonathan UK diy 19 September 11th 06 08:08 PM
REALISTIC TR-802 8-TRACK DECK-EBAY-one cent ! [email protected] Electronics Repair 2 January 13th 05 10:23 AM
shematic for realistic sta-860 raw38 Electronics Repair 6 December 1st 04 01:52 PM
Realistic MT-400 VHF Receiver Manual Jacques Carrier Electronics Repair 1 February 10th 04 11:04 PM
pro2020 realistic scanner eddumokweer Electronics Repair 2 October 6th 03 06:20 PM


All times are GMT +1. The time now is 08:38 AM.

Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 DIYbanter.
The comments are property of their posters.
 

About Us

"It's about DIY & home improvement"