I have just been reviewing our electricity usage.

We installed a bunch of panels on the roof almost 5 years ago so have a
good period over which to measure performance. They generate 3.7kW peak.

Our annual usage has been around 4.5MW +/- .4MW.
Our self consumption has been about a third of that - we use dishwasher
and washing machine when sun is shining mainly, as well as using excess
to power a small fan heater in winter or fan when hot.
We therefore export about 3MW per year.

Our import from the grid is very similar to our self-consumption, so
overall our panels result in a net contribution of around 1.5MW a year.

For this we pay around £50/m in electricity bills to Octopus! Seems
outrageous, until you realise that we generate when everyone else is and
so prices are low, and vice versa for usage.

The panels have definitely been worth it as we get around £400 FIT
payments and save at least as much on our bills, so the panels will be
repaid in 3-4 years. We will of course continue to get a benefit for
many years with perhaps a small drop off in performance.

I am still not tempted to fit batteries though. My analysis is still the
same - I could save around 70% of my bill by installing a 3kWh battery,
but payback would be more than 10 years at which time performance could
have deteriorated significantly.
A larger battery would save a bit more but peak saving is still only
around 80%.

I'd be interested to see numbers from otherats - Mike has your system
been live for a year yet ? Sally, how is it going with your heat pumop
- do you have batteries ? Chris, do you have batteries ?

I was interested to read recently that total reliance on wind and solar
would require storage of 3 months worth of electricity usage. Sounds
crazy, but this is a water engineer who is used to this type of
calculation for reservoirs etc. where you simply cannot run dry.
What people forget is that demand is highest at this time of year when
solar is at its lowest production and wind can be very low also for
several days when the conditions are right. So not only is a lot being
used, but there is little spare to top up the batteries.

On 08/12/2023 10:36, BrritSki wrote:
> I have just been reviewing our electricity usage.
>
> We installed a bunch of panels on the roof almost 5 years ago so have a
> good period over which to measure performance. They generate 3.7kW peak.
>
> Our annual usage has been around 4.5MW +/- .4MW.
> Our self consumption has been about a third of that - we use dishwasher
> and washing machine when sun is shining mainly, as well as using excess
> to power a small fan heater in winter or fan when hot.
> We therefore export about 3MW per year.
>
> Our import from the grid is very similar to our self-consumption, so
> overall our panels result in a net contribution of around 1.5MW a year.
>
<snip>

A Pedant asks:

Should some of those MW be MWhr? Otherwise you seem to be confusing
power and energy which I find surprising for an engineer.

john

On 08/12/2023 11:13, John Ashby wrote:
> On 08/12/2023 10:36, BrritSki wrote:
>> I have just been reviewing our electricity usage.
>>
>> We installed a bunch of panels on the roof almost 5 years ago so have
>> a good period over which to measure performance. They generate 3.7kW
>> peak.
>>
>> Our annual usage has been around 4.5MW +/- .4MW.
>> Our self consumption has been about a third of that - we use
>> dishwasher and washing machine when sun is shining mainly, as well as
>> using excess to power a small fan heater in winter or fan when hot.
>> We therefore export about 3MW per year.
>>
>> Our import from the grid is very similar to our self-consumption, so
>> overall our panels result in a net contribution of around 1.5MW a year.
>>
> <snip>
>
> A Pedant asks:
>
> Should some of those MW be MWhr? Otherwise you seem to be confusing
> power and energy which I find surprising for an engineer.
>
ALmost certainly. I is not an engineer, but I can speel it.

On 8.12.23 12:03, BrritSki wrote:
> On 08/12/2023 11:13, John Ashby wrote:
>> On 08/12/2023 10:36, BrritSki wrote:
>>> I have just been reviewing our electricity usage.
>>>
>>> We installed a bunch of panels on the roof almost 5 years ago so have
>>> a good period over which to measure performance. They generate 3.7kW
>>> peak.
>>>
>>> Our annual usage has been around 4.5MW +/- .4MW.
>>> Our self consumption has been about a third of that - we use
>>> dishwasher and washing machine when sun is shining mainly, as well as
>>> using excess to power a small fan heater in winter or fan when hot.
>>> We therefore export about 3MW per year.
>>>
>>> Our import from the grid is very similar to our self-consumption, so
>>> overall our panels result in a net contribution of around 1.5MW a year.
>>>
>> <snip>
>>
>> A Pedant asks:
>>
>> Should some of those MW be MWhr? Otherwise you seem to be confusing
>> power and energy which I find surprising for an engineer.
>>
> ALmost certainly. I is not  an engineer, but I can speel it.
>

So there you were saying nothing. So I closed Thunderbird and opened it
and there you are saying something. I had this a little pre-upgrade so
I am not sure if it is Thunderbird or plusnet (I miss aioe - seemingly
it is not returning).

--
Kosmo Richard W
www.travelswmw.whitnet.uk
https://tinyurl.com/KRWpics

BrritSki <rtilburyTAKEOUT@gmail.com> wrote:
> I have just been reviewing our electricity usage.
>
> We installed a bunch of panels on the roof almost 5 years ago so have a
> good period over which to measure performance. They generate 3.7kW peak.
>
> Our annual usage has been around 4.5MW +/- .4MW.
> Our self consumption has been about a third of that - we use dishwasher
> and washing machine when sun is shining mainly, as well as using excess
> to power a small fan heater in winter or fan when hot.
> We therefore export about 3MW per year.
>
> Our import from the grid is very similar to our self-consumption, so
> overall our panels result in a net contribution of around 1.5MW a year.
>
> For this we pay around £50/m in electricity bills to Octopus! Seems
> outrageous, until you realise that we generate when everyone else is and
> so prices are low, and vice versa for usage.
>
> The panels have definitely been worth it as we get around £400 FIT
> payments and save at least as much on our bills, so the panels will be
> repaid in 3-4 years. We will of course continue to get a benefit for
> many years with perhaps a small drop off in performance.
>
> I am still not tempted to fit batteries though. My analysis is still the
> same - I could save around 70% of my bill by installing a 3kWh battery,
> but payback would be more than 10 years at which time performance could
> have deteriorated significantly.
> A larger battery would save a bit more but peak saving is still only
> around 80%.
>
> I'd be interested to see numbers from otherats - Mike has your system
> been live for a year yet ? Sally, how is it going with your heat pumop
> - do you have batteries ? Chris, do you have batteries ?
>
> I was interested to read recently that total reliance on wind and solar
> would require storage of 3 months worth of electricity usage. Sounds
> crazy, but this is a water engineer who is used to this type of
> calculation for reservoirs etc. where you simply cannot run dry.
> What people forget is that demand is highest at this time of year when
> solar is at its lowest production and wind can be very low also for
> several days when the conditions are right. So not only is a lot being
> used, but there is little spare to top up the batteries.
>

Storage of energy is the trickiest part of supplying the world’s needs
which can vary second by second, minute by minute, hour by h…….. The UK
(and probably other nations too) use what is generally known as the ‘Duck
Curve’ to graphically illustrate how demand varies over 24 hours. The
problem is the peak demand (which can be many times higher than the base
load) that falls in the late afternoon when consumers start demanding huge
amounts of energy for heating, lighting, cooking, washing etc. At such
times, much of the high demand is ‘serviced’ by power obtained from fossil
fuels rather than cleaner sources.

Many schemes are now being employed in an attempt to ‘smooth over’ the high
demand peaks from energy stored derived in cleaner ways; hydroelectric,
nuclear and wind plus solar. Of course the instantaneous nature of wind and
solar means total reliance on them is just not possible. Methods such as
kinetic storage (damns, gert weights in shafts, massive heat storage in
sand, concrete and other materials are just a few schemes being employed /
experimented with. Recently, attempts have been employed to encourage
consumers to reduce their high demand by financial inducements - the energy
suppliers pay consumers if they use less than their typical consumption
during such peak times.

It is indeed a crazy world where we might be paid to not use so much power;
there was a saving session last week by my suppliers and by exporting a few
kW/h to them during the session, I am being rewarded with a payment of more
than £69! (‘Helping out’ the grid in this way was possible for me as I have
battery storage - I recharged the battery during the hours of lowest
demand) However, the sums involved sound crazy and one might wonder where
we are heading!!!!

From this readers will realise if they didn’t already know, we have battery
storage - sufficient to run our heat pump and the other electrical demand
of McToodle Villas (we are all-electric and no gas these days) and charge
during the cheapest 6 hours in every 24 without resorting to energy at 2.5
x the price at other times.

We have 8.1 kWp. Of solar PV and in the year we have had battery storage as
well, we have exported 3.5 MW/h and imported 6.6 MW/h. The summer we
experienced this year was (I hope!!!) rather extreme and lousey for
photons! I cannot give a clearer picture of our overall ‘production’ or
generation as the Enphase monitoring equipment attached to the PV array has
gone bonkers (awaiting a visit from the installers to rectify now) and is
giving crazy reports of production and consumption. The figures above are
from the Tesla app attached to my system. Last summer produced better
photon benefits from Aug, 8th. 2022 - Nov. 4th. 2022; we produced 1.5 MW/h,
we exported 1.0 MW/h and consumed 476.1 kW/h during that time. Not only
were the photons scarcer this summer (summer?!) but part of the array was
shaded with scaffolding for some time when shoddy install work was being
rectified.

Our electrical consumption has shot up - but that is because we no longer
use gas and that accounted for many more kW/h than we now use.

--
Toodle Pip, Mike McMillan

Mike McMillan <toodle.pip1@virginmedia.com> wrote:
> BrritSki <rtilburyTAKEOUT@gmail.com> wrote:
>> I have just been reviewing our electricity usage.
>>
>> We installed a bunch of panels on the roof almost 5 years ago so have a
>> good period over which to measure performance. They generate 3.7kW peak.
>>
>> Our annual usage has been around 4.5MW +/- .4MW.
>> Our self consumption has been about a third of that - we use dishwasher
>> and washing machine when sun is shining mainly, as well as using excess
>> to power a small fan heater in winter or fan when hot.
>> We therefore export about 3MW per year.
>>
>> Our import from the grid is very similar to our self-consumption, so
>> overall our panels result in a net contribution of around 1.5MW a year.
>>
>> For this we pay around £50/m in electricity bills to Octopus! Seems
>> outrageous, until you realise that we generate when everyone else is and
>> so prices are low, and vice versa for usage.
>>
>> The panels have definitely been worth it as we get around £400 FIT
>> payments and save at least as much on our bills, so the panels will be
>> repaid in 3-4 years. We will of course continue to get a benefit for
>> many years with perhaps a small drop off in performance.
>>
>> I am still not tempted to fit batteries though. My analysis is still the
>> same - I could save around 70% of my bill by installing a 3kWh battery,
>> but payback would be more than 10 years at which time performance could
>> have deteriorated significantly.
>> A larger battery would save a bit more but peak saving is still only
>> around 80%.
>>
>> I'd be interested to see numbers from otherats - Mike has your system
>> been live for a year yet ? Sally, how is it going with your heat pumop
>> - do you have batteries ? Chris, do you have batteries ?
>>
>> I was interested to read recently that total reliance on wind and solar
>> would require storage of 3 months worth of electricity usage. Sounds
>> crazy, but this is a water engineer who is used to this type of
>> calculation for reservoirs etc. where you simply cannot run dry.
>> What people forget is that demand is highest at this time of year when
>> solar is at its lowest production and wind can be very low also for
>> several days when the conditions are right. So not only is a lot being
>> used, but there is little spare to top up the batteries.
>>
>
> Storage of energy is the trickiest part of supplying the world’s needs
> which can vary second by second, minute by minute, hour by h…….. The UK
> (and probably other nations too) use what is generally known as the ‘Duck
> Curve’ to graphically illustrate how demand varies over 24 hours. The
> problem is the peak demand (which can be many times higher than the base
> load) that falls in the late afternoon when consumers start demanding huge
> amounts of energy for heating, lighting, cooking, washing etc. At such
> times, much of the high demand is ‘serviced’ by power obtained from fossil
> fuels rather than cleaner sources.
>
> Many schemes are now being employed in an attempt to ‘smooth over’ the high
> demand peaks from energy stored derived in cleaner ways; hydroelectric,
> nuclear and wind plus solar. Of course the instantaneous nature of wind and
> solar means total reliance on them is just not possible. Methods such as
> kinetic storage (damns, gert weights in shafts, massive heat storage in
> sand, concrete and other materials are just a few schemes being employed /
> experimented with. Recently, attempts have been employed to encourage
> consumers to reduce their high demand by financial inducements - the energy
> suppliers pay consumers if they use less than their typical consumption
> during such peak times.
>
> It is indeed a crazy world where we might be paid to not use so much power;
> there was a saving session last week by my suppliers and by exporting a few
> kW/h to them during the session, I am being rewarded with a payment of more
> than £69! (‘Helping out’ the grid in this way was possible for me as I have
> battery storage - I recharged the battery during the hours of lowest
> demand) However, the sums involved sound crazy and one might wonder where
> we are heading!!!!
>
> From this readers will realise if they didn’t already know, we have battery
> storage - sufficient to run our heat pump and the other electrical demand
> of McToodle Villas (we are all-electric and no gas these days) and charge
> during the cheapest 6 hours in every 24 without resorting to energy at 2.5
> x the price at other times.
>
> We have 8.1 kWp. Of solar PV and in the year we have had battery storage as
> well, we have exported 3.5 MW/h and imported 6.6 MW/h. The summer we
> experienced this year was (I hope!!!) rather extreme and lousey for
> photons! I cannot give a clearer picture of our overall ‘production’ or
> generation as the Enphase monitoring equipment attached to the PV array has
> gone bonkers (awaiting a visit from the installers to rectify now) and is
> giving crazy reports of production and consumption. The figures above are
> from the Tesla app attached to my system. Last summer produced better
> photon benefits from Aug, 8th. 2022 - Nov. 4th. 2022; we produced 1.5 MW/h,
> we exported 1.0 MW/h and consumed 476.1 kW/h during that time. Not only
> were the photons scarcer this summer (summer?!) but part of the array was
> shaded with scaffolding for some time when shoddy install work was being
> rectified.
>
> Our electrical consumption has shot up - but that is because we no longer
> use gas and that accounted for many more kW/h than we now use.
>

In case anyRats are wondering about the consumption of our heat pump,
during the ‘cold snap’ last week, we were running at approx. 1.5 kW/h each
hour to heat the whole house; today, we are running at approx. 800 Watts
per hour. This is a great deal less than the kW/h’s we consumed when we
were ‘cooking with gas’ so to speak. Some of this higher consumption could
well have been blamed on Gritish Bas who installed the boiler some 15 years
or so ago; they install their BG badged systems set at a default rate of
output - ‘never mind the required heat for the particular property’s needs,
we sell gas and customers pay for it’. I asked their engineers about this
and they leave the default settings alone and sod the customer’s real need.
Such is life!

--
Toodle Pip, Mike McMillan

Mike McMillan <toodle.pip1@virginmedia.com> wrote:
> Mike McMillan <toodle.pip1@virginmedia.com> wrote:
>> BrritSki <rtilburyTAKEOUT@gmail.com> wrote:
>>> I have just been reviewing our electricity usage.
>>>
>>> We installed a bunch of panels on the roof almost 5 years ago so have a
>>> good period over which to measure performance. They generate 3.7kW peak.
>>>
>>> Our annual usage has been around 4.5MW +/- .4MW.
>>> Our self consumption has been about a third of that - we use dishwasher
>>> and washing machine when sun is shining mainly, as well as using excess
>>> to power a small fan heater in winter or fan when hot.
>>> We therefore export about 3MW per year.
>>>
>>> Our import from the grid is very similar to our self-consumption, so
>>> overall our panels result in a net contribution of around 1.5MW a year.
>>>
>>> For this we pay around £50/m in electricity bills to Octopus! Seems
>>> outrageous, until you realise that we generate when everyone else is and
>>> so prices are low, and vice versa for usage.
>>>
>>> The panels have definitely been worth it as we get around £400 FIT
>>> payments and save at least as much on our bills, so the panels will be
>>> repaid in 3-4 years. We will of course continue to get a benefit for
>>> many years with perhaps a small drop off in performance.
>>>
>>> I am still not tempted to fit batteries though. My analysis is still the
>>> same - I could save around 70% of my bill by installing a 3kWh battery,
>>> but payback would be more than 10 years at which time performance could
>>> have deteriorated significantly.
>>> A larger battery would save a bit more but peak saving is still only
>>> around 80%.
>>>
>>> I'd be interested to see numbers from otherats - Mike has your system
>>> been live for a year yet ? Sally, how is it going with your heat pumop
>>> - do you have batteries ? Chris, do you have batteries ?
>>>
>>> I was interested to read recently that total reliance on wind and solar
>>> would require storage of 3 months worth of electricity usage. Sounds
>>> crazy, but this is a water engineer who is used to this type of
>>> calculation for reservoirs etc. where you simply cannot run dry.
>>> What people forget is that demand is highest at this time of year when
>>> solar is at its lowest production and wind can be very low also for
>>> several days when the conditions are right. So not only is a lot being
>>> used, but there is little spare to top up the batteries.
>>>
>>
>> Storage of energy is the trickiest part of supplying the world’s needs
>> which can vary second by second, minute by minute, hour by h…….. The UK
>> (and probably other nations too) use what is generally known as the ‘Duck
>> Curve’ to graphically illustrate how demand varies over 24 hours. The
>> problem is the peak demand (which can be many times higher than the base
>> load) that falls in the late afternoon when consumers start demanding huge
>> amounts of energy for heating, lighting, cooking, washing etc. At such
>> times, much of the high demand is ‘serviced’ by power obtained from fossil
>> fuels rather than cleaner sources.
>>
>> Many schemes are now being employed in an attempt to ‘smooth over’ the high
>> demand peaks from energy stored derived in cleaner ways; hydroelectric,
>> nuclear and wind plus solar. Of course the instantaneous nature of wind and
>> solar means total reliance on them is just not possible. Methods such as
>> kinetic storage (damns, gert weights in shafts, massive heat storage in
>> sand, concrete and other materials are just a few schemes being employed /
>> experimented with. Recently, attempts have been employed to encourage
>> consumers to reduce their high demand by financial inducements - the energy
>> suppliers pay consumers if they use less than their typical consumption
>> during such peak times.
>>
>> It is indeed a crazy world where we might be paid to not use so much power;
>> there was a saving session last week by my suppliers and by exporting a few
>> kW/h to them during the session, I am being rewarded with a payment of more
>> than £69! (‘Helping out’ the grid in this way was possible for me as I have
>> battery storage - I recharged the battery during the hours of lowest
>> demand) However, the sums involved sound crazy and one might wonder where
>> we are heading!!!!
>>
>> From this readers will realise if they didn’t already know, we have battery
>> storage - sufficient to run our heat pump and the other electrical demand
>> of McToodle Villas (we are all-electric and no gas these days) and charge
>> during the cheapest 6 hours in every 24 without resorting to energy at 2.5
>> x the price at other times.
>>
>> We have 8.1 kWp. Of solar PV and in the year we have had battery storage as
>> well, we have exported 3.5 MW/h and imported 6.6 MW/h. The summer we
>> experienced this year was (I hope!!!) rather extreme and lousey for
>> photons! I cannot give a clearer picture of our overall ‘production’ or
>> generation as the Enphase monitoring equipment attached to the PV array has
>> gone bonkers (awaiting a visit from the installers to rectify now) and is
>> giving crazy reports of production and consumption. The figures above are
>> from the Tesla app attached to my system. Last summer produced better
>> photon benefits from Aug, 8th. 2022 - Nov. 4th. 2022; we produced 1.5 MW/h,
>> we exported 1.0 MW/h and consumed 476.1 kW/h during that time. Not only
>> were the photons scarcer this summer (summer?!) but part of the array was
>> shaded with scaffolding for some time when shoddy install work was being
>> rectified.
>>
>> Our electrical consumption has shot up - but that is because we no longer
>> use gas and that accounted for many more kW/h than we now use.
>>
>
> In case anyRats are wondering about the consumption of our heat pump,
> during the ‘cold snap’ last week, we were running at approx. 1.5 kW/h each
> hour to heat the whole house; today, we are running at approx. 800 Watts
> per hour. This is a great deal less than the kW/h’s we consumed when we
> were ‘cooking with gas’ so to speak. Some of this higher consumption could
> well have been blamed on Gritish Bas who installed the boiler some 15 years
> or so ago; they install their BG badged systems set at a default rate of
> output - ‘never mind the required heat for the particular property’s needs,
> we sell gas and customers pay for it’. I asked their engineers about this
> and they leave the default settings alone and sod the customer’s real need.
> Such is life!
>

Oh, and one more thing - Since day one (early Aug. 2022) our solar PV has
produced 8.88MW/h.

--
Toodle Pip, Mike McMillan

BrritSki wrote:

>I have just been reviewing our electricity usage.

>I am still not tempted to fit batteries though. My analysis is still the
>same - I could save around 70% of my bill by installing a 3kWh battery,
>but payback would be more than 10 years at which time performance could
>have deteriorated significantly.
>A larger battery would save a bit more but peak saving is still only
>around 80%.
>
>I'd be interested to see numbers from otherats - Mike has your system
>been live for a year yet ? Sally, how is it going with your heat pumop
>- do you have batteries ? Chris, do you have batteries ?

No batteries here. My system is 3.64 kWp, with an annual output
averaging 3.6 MWh. That used to be about the same as our usage,
but, obviously, not at the same time of day.

The investment in 2010 paid back the cost during 2018, and
currently I am in profit by more than I invested, which is better
than anything else I put my money in.

BOFE now has an electric car, which has increased our demand
somewhat.

My instinct is that batteries, for me, would not be financially
attractive, but I have not done the calculations. Unusually for
me, I did respond to a cold-caller who wanted to sell batteries,
in the hope that at least it would give me some detail
information, plus a payback calculation to audit and correct, but
they never followed up on the visit. Perhaps they thought I knew
too much!

With the current regime replacing the adimttedly generous FIT
that I have, I get the impression that a better argument for
batteries can be made.

Chris
--
Chris J Dixon Nottingham
'48/33 M B+ G++ A L(-) I S-- CH0(--)(p) Ar- T+ H0 ?Q
chris@cdixon.me.uk @ChrisJDixon1
Plant amazing Acers.

Chris J Dixon wrote:

I thought, I'll let the spell check sort out the typo, then I hit
"Ignore" :-(

Chris
--
Chris J Dixon Nottingham
'48/33 M B+ G++ A L(-) I S-- CH0(--)(p) Ar- T+ H0 ?Q
chris@cdixon.me.uk @ChrisJDixon1
Plant amazing Acers.

Chris J Dixon <chris@cdixon.me.uk> wrote:
> BrritSki wrote:
>
>> I have just been reviewing our electricity usage.
>
>> I am still not tempted to fit batteries though. My analysis is still the
>> same - I could save around 70% of my bill by installing a 3kWh battery,
>> but payback would be more than 10 years at which time performance could
>> have deteriorated significantly.
>> A larger battery would save a bit more but peak saving is still only
>> around 80%.
>>
>> I'd be interested to see numbers from otherats - Mike has your system
>> been live for a year yet ? Sally, how is it going with your heat pumop
>> - do you have batteries ? Chris, do you have batteries ?
>
> No batteries here. My system is 3.64 kWp, with an annual output
> averaging 3.6 MWh. That used to be about the same as our usage,
> but, obviously, not at the same time of day.
>
> The investment in 2010 paid back the cost during 2018, and
> currently I am in profit by more than I invested, which is better
> than anything else I put my money in.
>
> BOFE now has an electric car, which has increased our demand
> somewhat.
>
> My instinct is that batteries, for me, would not be financially
> attractive, but I have not done the calculations. Unusually for
> me, I did respond to a cold-caller who wanted to sell batteries,
> in the hope that at least it would give me some detail
> information, plus a payback calculation to audit and correct, but
> they never followed up on the visit. Perhaps they thought I knew
> too much!
>
> With the current regime replacing the adimttedly generous FIT
> that I have, I get the impression that a better argument for
> batteries can be made.
>
> Chris

Our system doesn’t benefit from the very generous FIT so our calculations
are based on a very different basis. Paying 16.51 pence per kW/h during two
3 hour periods per day goes a fair way to justifying some storage capacity
thus avoiding paying greater rates for the other 18 hours. Yes, I know
storage costs a great deal but an additional benefit is the security from
power outages - they were only short terms (a few minutes each) breaks in
supply recently but all we knew was that Tesla app reported to us that they
had occurred at all! Previously we had a 12 hour outage which meant we had
no heating, no cooking, no lighting…

--
Toodle Pip, Mike McMillan

On 08/12/2023 17:12, Mike McMillan wrote:

<snipped>

> In case anyRats are wondering about the consumption of our heat pump,
> during the ‘cold snap’ last week, we were running at approx. 1.5 kW/h

Arrgh!

> each hour > to heat the whole house; today, we are running at approx. 800 Watts
> per hour.

Arrrgh!

> This is a great deal less than the kW/h’s

Someone, please make it stop!

> we consumed when we
> were ‘cooking with gas’ so to speak.

You are a Grauniad science journalist AICMFP.

--
Cheers
Clive

Clive Arthur <clive@nowaytoday.co.uk> wrote:
> On 08/12/2023 17:12, Mike McMillan wrote:
>
> <snipped>
>
>> In case anyRats are wondering about the consumption of our heat pump,
>> during the ‘cold snap’ last week, we were running at approx. 1.5 kW/h
>
> Arrgh!
>
>> each hour > to heat the whole house; today, we are running at approx. 800 Watts
>> per hour.
>
> Arrrgh!
>
>> This is a great deal less than the kW/h’s
>
> Someone, please make it stop!
>
>> we consumed when we
>> were ‘cooking with gas’ so to speak.
>
> You are a Grauniad science journalist AICMFP.
>

Ok, Ok, very sorry, badly written I realise. What I was trying to indicate
was that the power varies greatly and I wanted to indicate an average ‘kW
hourage’; at times, the pump idles for some minutes at perhaps 200 - 500
watts then later it might be running at 1500 watts. The indications I have
are from a transitory metering on the Tesla app which updates, I think,
every 15 seconds and from an accumulated amount shown in two hour blocks on
the heat pump app. These blocks may show 1, 2 and sometimes 3 kW. Such
varying figures are probably best expressed when averaged - and I started
to write in terms of what I feel it consumes ‘per hour’. Guilty as charged!

--
Toodle Pip, Mike McMillan

On 08/12/2023 16:19, Mike McMillan wrote:
> BrritSki <rtilburyTAKEOUT@gmail.com> wrote:
>> I have just been reviewing our electricity usage.

>><snip>
>> I should of course have said: Our annual PRODUCTION has been around 4.5MWh ± .4MWh.
>
> We have 8.1 kWp. Of solar PV and in the year we have had battery storage as
> well, we have exported 3.5 MW/h and imported 6.6 MW/h. The summer we
> experienced this year was (I hope!!!) rather extreme and lousey for
> photons!

Although the summer months were relatively poor, overall this year has
already beaten 2021 and matched 2019 (which had a zero for January,
probably similar to missing days for rest of this December). Not far
behind 2020 and 22 which both had 4.8MWh as we are already at 4.4MWh
with 3 weeks still to go.
Feb, Jun and Nov this year were best ever for those months in last 5 years

On 08/12/2023 17:12, Mike McMillan wrote:
> In case anyRats are wondering about the consumption of our heat pump,
> during the ‘cold snap’ last week, we were running at approx. 1.5 kW/h each
> hour to heat the whole house; today, we are running at approx. 800 Watts
> per hour. This is a great deal less than the kW/h’s we consumed when we
> were ‘cooking with gas’ so to speak. Some of this higher consumption could
> well have been blamed on Gritish Bas who installed the boiler some 15 years
> or so ago; they install their BG badged systems set at a default rate of
> output - ‘never mind the required heat for the particular property’s needs,
> we sell gas and customers pay for it’. I asked their engineers about this
> and they leave the default settings alone and sod the customer’s real need.
> Such is life!
>
Crikey. We had a new boiler installed 5 years ago and have it adjusted
to run slightly cooler than the recommended setting which works well for
us for both heating and hot water. We have a good independent plumber
who advises us on this and does annual service.
The most gas we used in the last year was December last year at 1.971MWh
for the whole month. Recently we have been using about 10MWh for the
whole year. This is a drop from around 13MWH a couple of years ago when
prices started to escalate.
With the relative prices of electricity and gas this is considerably
less than we would pay with a heat pump without a huge outlay for more
panels and batteries as well as the heat pump itself. We don't think
that outlay justifies the savings for us or the planet. YMMV

We now have the CH on from 7.20-10.00 and 16.00-2100 with a setting of
19.5. That is fine for the morning as we come down at about 8 to a warm
room and are moving around making breakfast even on a cold day. As I
write the temp in living room is 18 which is OK as long as you're not
just sitting but of course today is relatively mild at 10 outside and
we'll soon be making lunch to warm things up
If the smart switch doesn't turn the fan heater on we will often give
the heating a blast for half an hour or so and in the evenings it often
needs to be turned up to 20.5. We don't sit around in t shirts of course.
The min temperature is set to 15C which meant that the CH came on 30
minutes early a couple of times during the cold snap, but we were fine
under our duvets.
On really cold miserable days we light the log burner in the afternoon,
but we've only done that once this year. The trouble with that is
downstairs is hot but upstairs is too cold so we still need to run the
CH for at least 30 mins before we go to bed.
We don't like warm bedrooms though and both sleep with the window open a
crack. Waife has an electric blanket to warm her bed up, but turns it
off to sleep.
We have TRVs on all the radiators and set to about halfway upstairs and
full downstairs. We think the walls must have cavity insulation, but not
100% sure. Double glazing is old and not great, so we have thick thermal
curtains. A couple of years ago I cleared out the loft, put in a second
set of joists and a new floor and doubled the amount of insulation
throughout to 200mm. I also devised a sliding insulated cushion that
covers the trap door (which is itself insulated) for the winter months
and we immediately noticed it warmer upstairs. We went in the loft a
couple of days ago and it was just like being outside. Excellent !

On 08/12/2023 17:27, Chris J Dixon wrote:
> BrritSki wrote:
>
Thanks for the info.

> My instinct is that batteries, for me, would not be financially
> attractive, but I have not done the calculations. Unusually for
> me, I did respond to a cold-caller who wanted to sell batteries,
> in the hope that at least it would give me some detail
> information, plus a payback calculation...

If you can download your daily generation/usage etc I can send you my
spreadsheet that will let you do the calculation by day throughout the
year. Let me know by email.

On Sat, 9 Dec 2023 12:56:24 +0000, BrritSki
<rtilburyTAKEOUT@gmail.com> wrote:
<snip>
>Crikey. We had a new boiler installed 5 years ago and have it adjusted
>to run slightly cooler than the recommended setting which works well for
>us for both heating and hot water.

<snip>

+1 on the boiler output. Dunno about the rest because I don't have the
rest of what you have.

AIUI most boilers these days (including mine) are condensing boilers
which means they are designed to reclaim some of the waste heat to
pre-heat the water before the boiler does its thing. AIUI2 if the
boiler is running too hot then the condensation factor doesn't come
into play. The only downside that I know of running the system
slightly cooler is that it takes slightly longer to bring the rooms up
to normal temperature from a cold start.

Nick

On Fri, 08 Dec 2023 17:27:59 +0000, Chris J Dixon <chris@cdixon.me.uk>
scrawled in the dust...

>My instinct is that batteries, for me, would not be financially
>attractive, but I have not done the calculations. Unusually for
>me, I did respond to a cold-caller who wanted to sell batteries,
>in the hope that at least it would give me some detail
>information, plus a payback calculation to audit and correct, but
>they never followed up on the visit. Perhaps they thought I knew
>too much

I indicated an interest from an ad on Facebook a while back, which had a
tagline of 'how much is battery storage?' or similar. A week or so later I
had a phone call asking how many responses I'd had, from which I realised
this was some sort of agency. No one had contacted me and the chap didn't
seem to have any idea of costs himself, so that was a waste of time, as far
as I could see. He did seem surprised my FIT payments had been covering my
gas and electric bills for years.

I have since dug out a vague cost and decided it was not worth pursuing. My
children really want me to move...
--
Penny
Annoyed by The Archers since 1959

Penny <spam@labyrinth.freeuk.com> wrote:
> On Fri, 08 Dec 2023 17:27:59 +0000, Chris J Dixon <chris@cdixon.me.uk>
> scrawled in the dust...
>
>> My instinct is that batteries, for me, would not be financially
>> attractive, but I have not done the calculations. Unusually for
>> me, I did respond to a cold-caller who wanted to sell batteries,
>> in the hope that at least it would give me some detail
>> information, plus a payback calculation to audit and correct, but
>> they never followed up on the visit. Perhaps they thought I knew
>> too much
>
> I indicated an interest from an ad on Facebook a while back, which had a
> tagline of 'how much is battery storage?' or similar. A week or so later I
> had a phone call asking how many responses I'd had, from which I realised
> this was some sort of agency. No one had contacted me and the chap didn't
> seem to have any idea of costs himself, so that was a waste of time, as far
> as I could see. He did seem surprised my FIT payments had been covering my
> gas and electric bills for years.
>
> I have since dug out a vague cost and decided it was not worth pursuing. My
> children really want me to move...

Just checked our consumption on this very mild day and over the last 16
hours, our heat pump consumption has averaged 625 watt/h.

--
Toodle Pip, Mike McMillan

BrritSki <rtilburyTAKEOUT@gmail.com> wrote:
> On 08/12/2023 17:12, Mike McMillan wrote:
>> In case anyRats are wondering about the consumption of our heat pump,
>> during the ‘cold snap’ last week, we were running at approx. 1.5 kW/h each
>> hour to heat the whole house; today, we are running at approx. 800 Watts
>> per hour. This is a great deal less than the kW/h’s we consumed when we
>> were ‘cooking with gas’ so to speak. Some of this higher consumption could
>> well have been blamed on Gritish Bas who installed the boiler some 15 years
>> or so ago; they install their BG badged systems set at a default rate of
>> output - ‘never mind the required heat for the particular property’s needs,
>> we sell gas and customers pay for it’. I asked their engineers about this
>> and they leave the default settings alone and sod the customer’s real need.
>> Such is life!
>>
> Crikey. We had a new boiler installed 5 years ago and have it adjusted
> to run slightly cooler than the recommended setting which works well for
> us for both heating and hot water. We have a good independent plumber
> who advises us on this and does annual service.
>

I was very green (but in the wrong way) in the 2000’s when we needed a new
Bas Goiler; the BG salesman / surveyor was able to provide a condensing
boiler - no problem but…. What he didn’t tell us was that the boiler would
be fitted set to 16 kWh/h whether we needed 6-8-10-12 or whatever kW
rating. Neither were we told that there was just one temperature controller
- for hot water and heating. The result of a single control being that we
could not set the radiators for anything less than the requirement for the
hot water temperature. :-((( Over the years, Gritish Bas raised the annual
service contract fee and though the servicing was described as ‘annual’ to
them, this meant every 18-24 months as and when they felt inclined to ‘fit
us in’. I was not amused and was very glad to remove our needs from their
clutches eventually.

--
Toodle Pip, Mike McMillan

Mike McMillan <toodle.pip1@virginmedia.com> wrote:

>
> I was very green (but in the wrong way) in the 2000’s when we needed a new
> Bas Goiler; the BG salesman / surveyor was able to provide a condensing
> boiler - no problem but…. What he didn’t tell us was that the boiler would
> be fitted set to 16 kWh/h whether we needed 6-8-10-12 or whatever kW
> rating. Neither were we told that there was just one temperature controller
> - for hot water and heating. The result of a single control being that we
> could not set the radiators for anything less than the requirement for the
> hot water temperature. :-((( Over the years, Gritish Bas raised the annual
> service contract fee and though the servicing was described as ‘annual’ to
> them, this meant every 18-24 months as and when they felt inclined to ‘fit
> us in’. I was not amused and was very glad to remove our needs from their
> clutches eventually.
>

Mined Ewe, that system was better than the very first system we had
installed at our previous Toodle Villas in the seventies, it was a
‘Servowarm’ system. One delightful ‘feature’ was the three way valve with a
rocking lever used to send the energy to the heating or the hot water. Any
attempt to have a mixture resulted in an horrendous noise due to turbulence
in the valve. The outcome being that one needed to select one route or the
other and remember to change over so as to have a warm house and hot water!
Just don’t get me started about the very lightweight (supposedly for fast
response to heat demand) heat exchanger which had burning gas applied
seconds before the pump got going to circulate the energy, and as a result,
scaled up the heat exchanger body so that it ‘kettled’. We had quite a few
hx’s in the first year of life!

--
Toodle Pip, Mike McMillan

On 09/12/2023 17:37, Mike McMillan wrote:
> Mike McMillan <toodle.pip1@virginmedia.com> wrote:
>
>>
>> I was very green (but in the wrong way) in the 2000’s when we needed a new
>> Bas Goiler; the BG salesman / surveyor was able to provide a condensing
>> boiler - no problem but…. What he didn’t tell us was that the boiler would
>> be fitted set to 16 kWh/h whether we needed 6-8-10-12 or whatever kW
>> rating. Neither were we told that there was just one temperature controller
>> - for hot water and heating. The result of a single control being that we
>> could not set the radiators for anything less than the requirement for the
>> hot water temperature. :-((( Over the years, Gritish Bas raised the annual
>> service contract fee and though the servicing was described as ‘annual’ to
>> them, this meant every 18-24 months as and when they felt inclined to ‘fit
>> us in’. I was not amused and was very glad to remove our needs from their
>> clutches eventually.
>>
>
> Mined Ewe, that system was better than the very first system we had
> installed at our previous Toodle Villas in the seventies, it was a
> ‘Servowarm’ system. One delightful ‘feature’ was the three way valve with a
> rocking lever used to send the energy to the heating or the hot water. Any
> attempt to have a mixture resulted in an horrendous noise due to turbulence
> in the valve. The outcome being that one needed to select one route or the
> other and remember to change over so as to have a warm house and hot water!
> Just don’t get me started about the very lightweight (supposedly for fast
> response to heat demand) heat exchanger which had burning gas applied
> seconds before the pump got going to circulate the energy, and as a result,
> scaled up the heat exchanger body so that it ‘kettled’. We had quite a few
> hx’s in the first year of life!
>

I may have mentioned before the hot water system in the first house I
ever bought (heating was by night storage heaters ,remember them?). The
hhot water was supplied by a gas Ascot which was situated above the
toilet in the bathroom. This had the unfortunate habit of delaying
ignition until there had been a sufficient build-up of gas to blow the
front panel off.If you were sitting on the toilet and your partner
decided to do the washing up you cold receive a nasty blow on the back
of your head from a kilogram of mild steel plate.

john

On 09/12/2023 17:06, Mike McMillan wrote:

<snip>

> Just checked our consumption on this very mild day and over the last 16
> hours, our heat pump consumption has averaged 625 watt/h.

As you know, a watt is a unit of power. Power is the rate at which
energy is used or generated, for example, a 2kW heater uses energy twice
as quickly as a 1kW heater and gives out twice as much heat.

A watt per hour (watt/h as you put it) is rate of change of power - not
really a useful unit in this context, and certainly not germane to power
consumption.

A watt-hour (watts x hours) is a unit of energy. Power used times the
amount of time it was used for. Energy is what you pay for, or what you
generate, or what a battery stores. The proper SI unit is joules or
watt-seconds, but watt-hours is maybe more convenient.

To lift, say, a 1 tonne weight up 1 meter needs a certain amount of
energy, approx 10kJ or 2.6 watt-hours[1]. You can do that (assuming
mechanical perfection) slowly or quickly, using low power for a long
time or high power for a short time, but the energy required is the same.

So I suspect your heat pump averaged 625 watts over the last 16 hours
which amounts to 10kWh.

[1] Interesting to note that lifting say a 2T car up 100m uses a bit
over half a kWh costing about 16p. I wouldn't do it for that.

--
Cheers
Clive

On Sat, 9 Dec 2023 17:37:53 -0000 (UTC), Mike McMillan
<toodle.pip1@virginmedia.com> wrote:

>Mined Ewe, that system was better than the very first system we had
>installed at our previous Toodle Villas in the seventies, it was a
>‘Servowarm’ system. One delightful ‘feature’ was the three way valve with a
>rocking lever used to send the energy to the heating or the hot water. Any
>attempt to have a mixture resulted in an horrendous noise due to turbulence
>in the valve. The outcome being that one needed to select one route or the
>other and remember to change over so as to have a warm house and hot water!
>Just don’t get me started about the very lightweight (supposedly for fast
>response to heat demand) heat exchanger which had burning gas applied
>seconds before the pump got going to circulate the energy, and as a result,
>scaled up the heat exchanger body so that it ‘kettled’. We had quite a few
>hx’s in the first year of life!

Ah, boilers I have known.....We had a Servowarm at one time. Was that
the one in the form of a gas fire with boiler behind/attached? The
memory is misty, probably a good thing. I know with more than one
boiler the flame would go out and have to be re-lit to make it do its
thing.

On 09/12/2023 18:03, Clive Arthur wrote:
> On 09/12/2023 17:06, Mike McMillan wrote:
>
> <snip>
>
>> Just checked our consumption on this very mild day and over the last 16
>> hours, our heat pump consumption has averaged 625 watt/h.
>
> As you know, a watt is a unit of power.  Power is the rate at which
> energy is used or generated, for example, a 2kW heater uses energy twice
> as quickly as a 1kW heater and gives out twice as much heat.
>
> A watt per hour (watt/h as you put it) is rate of change of power - not
> really a useful unit in this context, and certainly not germane to power
> consumption.
>
> A watt-hour (watts x hours) is a unit of energy.  Power used times the
> amount of time it was used for.  Energy is what you pay for, or what you
> generate, or what a battery stores.  The proper SI unit is joules or
> watt-seconds, but watt-hours is maybe more convenient.
>
> To lift, say,  a 1 tonne weight up 1 meter needs a certain amount of
> energy, approx 10kJ or 2.6 watt-hours[1].  You can do that (assuming
> mechanical perfection) slowly or quickly, using low power for a long
> time or high power for a short time, but the energy required is the same.
>
> So I suspect your heat pump averaged 625 watts over the last 16 hours
> which amounts to 10kWh.
>
> [1] Interesting to note that lifting say a 2T car up 100m uses a bit
> over half a kWh costing about 16p.  I wouldn't do it for that.
>

Thank you.

john

BrritSki <rtilburyTAKEOUT@gmail.com> wrote:
> I have just been reviewing our electricity usage.
>
> We installed a bunch of panels on the roof almost 5 years ago so have a
> good period over which to measure performance. They generate 3.7kW peak.
>
> Our annual usage has been around 4.5MW +/- .4MW.
> Our self consumption has been about a third of that - we use dishwasher
> and washing machine when sun is shining mainly, as well as using excess
> to power a small fan heater in winter or fan when hot.
> We therefore export about 3MW per year.
>
> Our import from the grid is very similar to our self-consumption, so
> overall our panels result in a net contribution of around 1.5MW a year.
>
> For this we pay around £50/m in electricity bills to Octopus! Seems
> outrageous, until you realise that we generate when everyone else is and
> so prices are low, and vice versa for usage.
>
> The panels have definitely been worth it as we get around £400 FIT
> payments and save at least as much on our bills, so the panels will be
> repaid in 3-4 years. We will of course continue to get a benefit for
> many years with perhaps a small drop off in performance.
>
> I am still not tempted to fit batteries though. My analysis is still the
> same - I could save around 70% of my bill by installing a 3kWh battery,
> but payback would be more than 10 years at which time performance could
> have deteriorated significantly.
> A larger battery would save a bit more but peak saving is still only
> around 80%.
>
> I'd be interested to see numbers from otherats - Mike has your system
> been live for a year yet ? Sally, how is it going with your heat pumop
> - do you have batteries ? Chris, do you have batteries ?
>
> I was interested to read recently that total reliance on wind and solar
> would require storage of 3 months worth of electricity usage. Sounds
> crazy, but this is a water engineer who is used to this type of
> calculation for reservoirs etc. where you simply cannot run dry.
> What people forget is that demand is highest at this time of year when
> solar is at its lowest production and wind can be very low also for
> several days when the conditions are right. So not only is a lot being
> used, but there is little spare to top up the batteries.
>

I'm with you on the batteries. I did the big sums and decided it wasn't
worth the extra (large) outlay. The heat pump is great and efficient, and
we are delighted with the solar panels. I have an EV so we are on an EV
electrickery tariff which gives very low cost in the bowels of the night,
so as well as charging the car if needed, we also put dishwasher and
washing machine on a timer to take advantage of that. However if we're
generating enough from the panels, I would put the washing machine on or
indeed leave the car plugged in. Very satisfying when it does a little
"ping" and tops up the car from the panels.

--
Sally in Shropshire, UK