Solar Panels - energy price hikes making them more worthwhile? 7 October 2021 at 1:59PM in Green & ethical MoneySaving 26 replies 707 views

countryhouse39

re-posting here for more views originally posted in 'energy' ...

We are lucky enough to live in an old house in the Scottish countryside (5bed, 3 reception) and as with many rural properties we aren't on the gas network. The people before us installed a GSHP for the heating and hot water, but they didn't install much in the way of insulation (out house is mostly pre 1900) so we have spent the last few years upgrading the insulation, and we installed some double glazing, but our electricity bills are still high as we use about 18-19000kwh a year...
With both of us WFH and 3 children I don't think we can reduce this much - so as you can imagine the recent massive hikes in energy prices are painful for us. We have been thinking of installing PV panels, maybe solar thermal too, but the possible savings didn't make it seem worth the outlay, however I am thinking that with the rise in energy prices that it will be worth it after all? Is anyone else in a similar situation? is it worth reconsidering so our bills go down? Can anyone advise on the best combination? we have roof space, sadly our south facing roof is also street facing and therefore unlikely to get planning permission for panels (conservation area) but we have a long west facing roof that is unobstructed. Any advise gratefully received

matelodave

this is my reply from the other thread plus my comments about solar thermal

Bear in mind that you tend to heat your house in the winter and use most of your leccy when the sun doesn't shine and the days are short even when it does. Even worse, in the winter the sun tends to be very low and any shadows can really affect the output, so look at how shadows from trees, other buildings and even telegraph poles fall on your roof from even quite a long way away.

You really do need to do your homework to see whether the outlay on panels (especially if you have to borrow the money) gives you a reasonable payback period.

When I installed my airsource heatpump eleven years ago, I discusse solar thermal with the installer and his advice was that as the cost of heating the hot water with a heat pump was almost negligible,  solar thermal was unlikely to pay back within a reasonable time - we consume around 2-3kwh a day heating water.

Leccy was a lot cheaper then but his forecast was around 15 years.

However, as I say, do the sums and work out how much energy you use and when and then work out how much it'll cost to put solar stuff in and see when and how much it's going to produce and whether it will match your consumption profile

shinytop

I'm pondering the same as a ASHP user.  However, everything I've read points to savings of a few hundred pounds a year and payback in 15 years plus.  That's not going to make much of a dent in your electricity bill (or mine).  As a heat pump user you might save a bit more in spring/autumn and if you use a lot of hot water you'll save all year round.   

Have you done all you can in terms of radiators/flow temperatures to optimise the GSHP?

ABrass

Probably yes.

If you're properly rural then you can go for a large ground mounted array, which should cut down on installation costs and allow you to go as large as you like.

The panels won't generate in the dark (obviously) so they won't cover your use in the mornings to bring the house up to temperature. But I've heard you should run GSHP at a lower level but for a longer time, so it might cover some daytime use in Autumn, Winter and Spring.

The classic challenge is that when you need to heat your house there is the least sunshine.

Solar thermal is mostly a dead end now, PV is so much easier to fit and the price of the panels has dropped off a roof.

Coastalwatch

countryhouse39 said:

re-posting here for more views originally posted in 'energy' ...

We are lucky enough to live in an old house in the Scottish countryside (5bed, 3 reception) and as with many rural properties we aren't on the gas network. The people before us installed a GSHP for the heating and hot water, but they didn't install much in the way of insulation (out house is mostly pre 1900) so we have spent the last few years upgrading the insulation, and we installed some double glazing, but our electricity bills are still high as we use about 18-19000kwh a year...
With both of us WFH and 3 children I don't think we can reduce this much - so as you can imagine the recent massive hikes in energy prices are painful for us. We have been thinking of installing PV panels, maybe solar thermal too, but the possible savings didn't make it seem worth the outlay, however I am thinking that with the rise in energy prices that it will be worth it after all? Is anyone else in a similar situation? is it worth reconsidering so our bills go down? Can anyone advise on the best combination? we have roof space, sadly our south facing roof is also street facing and therefore unlikely to get planning permission for panels (conservation area) but we have a long west facing roof that is unobstructed. Any advise gratefully received

Hi CH, quite a conundrum you've pointed out there which I suspect will only be resolved by researching, obtaining quotes and asking questions on here and elsewhere. I concur with all those posting replies so far.

A west facing roof is good in the summer, as is an east, but in winter, when it's most needed the output would be very limited. Try inputting your location and other info into the link below to give an indication of likely output from any sized solar panel array through the year. If it's definitely a nogo on the south facing roof do you have anywhere you could erect solar panels to face south in the rear of the property?

https://www.google.com/search?client=firefox-b-d&q=pvgis+v5

I've no experience of Solar thermal but believe PV would be a more flexible form of energy as any excess can then be directed to areas other than hot water.

We've nearly 9MW of panels on the roof, which is approx our consumption annually. Unfortunately generation in winter is least when we most need it. It does also cover approx 75 % of our EV  transportation.

Hence we import around 4.5 MW annually.

To assist in offsetting the cost of imports we invested in Ripple Energy's wind farm, which is scheduled to commence generation in December. By doing this the wholesale cost of our energy will be fixed for the life of the windfarm, circa 25 years. Approx 2.5p/kWh, other fixed costs such as energy distribution etc which must also be accommodated in the cost of energy are not affected so no saving can be made on these.

While Ripples first windfarm is sold out they have announced a second, with slightly better returns, so may be worth investigating. Having invested in their first community owned windfarm I then invested further in the company itself.

Along with double glazing, thermal blinds can also be fitted to reduce heat loss and I've even backed these up with 50mm thick sheets of Celotex, cut to fit in the returns of the window spaces. Not used in summer or on mild winter days but popped in place from late afternoon during periods of sub zero temperatures in the darker days of winter.

countryhouse39

shinytop said:

I'm pondering the same as a ASHP user.  However, everything I've read points to savings of a few hundred pounds a year and payback in 15 years plus.  That's not going to make much of a dent in your electricity bill (or mine).  As a heat pump user you might save a bit more in spring/autumn and if you use a lot of hot water you'll save all year round.   

Have you done all you can in terms of radiators/flow temperatures to optimise the GSHP?

I'm not sure we have done all we can to optimise the GSHP as we are not experts in it at all - can you advise how we could do this? 

countryhouse39

Coastalwatch said:

countryhouse39 said:

re-posting here for more views originally posted in 'energy' ...

We are lucky enough to live in an old house in the Scottish countryside (5bed, 3 reception) and as with many rural properties we aren't on the gas network. The people before us installed a GSHP for the heating and hot water, but they didn't install much in the way of insulation (out house is mostly pre 1900) so we have spent the last few years upgrading the insulation, and we installed some double glazing, but our electricity bills are still high as we use about 18-19000kwh a year...
With both of us WFH and 3 children I don't think we can reduce this much - so as you can imagine the recent massive hikes in energy prices are painful for us. We have been thinking of installing PV panels, maybe solar thermal too, but the possible savings didn't make it seem worth the outlay, however I am thinking that with the rise in energy prices that it will be worth it after all? Is anyone else in a similar situation? is it worth reconsidering so our bills go down? Can anyone advise on the best combination? we have roof space, sadly our south facing roof is also street facing and therefore unlikely to get planning permission for panels (conservation area) but we have a long west facing roof that is unobstructed. Any advise gratefully received

Hi CH, quite a conundrum you've pointed out there which I suspect will only be resolved by researching, obtaining quotes and asking questions on here and elsewhere. I concur with all those posting replies so far.

A west facing roof is good in the summer, as is an east, but in winter, when it's most needed the output would be very limited. Try inputting your location and other info into the link below to give an indication of likely output from any sized solar panel array through the year. If it's definitely a nogo on the south facing roof do you have anywhere you could erect solar panels to face south in the rear of the property?

https://www.google.com/search?client=firefox-b-d&q=pvgis+v5

I've no experience of Solar thermal but believe PV would be a more flexible form of energy as any excess can then be directed to areas other than hot water.

We've nearly 9MW of panels on the roof, which is approx our consumption annually. Unfortunately generation in winter is least when we most need it. It does also cover approx 75 % of our EV  transportation.

Hence we import around 4.5 MW annually.

To assist in offsetting the cost of imports we invested in Ripple Energy's wind farm, which is scheduled to commence generation in December. By doing this the wholesale cost of our energy will be fixed for the life of the windfarm, circa 25 years. Approx 2.5p/kWh, other fixed costs such as energy distribution etc which must also be accommodated in the cost of energy are not affected so no saving can be made on these.

While Ripples first windfarm is sold out they have announced a second, with slightly better returns, so may be worth investigating. Having invested in their first community owned windfarm I then invested further in the company itself.

Along with double glazing, thermal blinds can also be fitted to reduce heat loss and I've even backed these up with 50mm thick sheets of Celotex, cut to fit in the returns of the window spaces. Not used in summer or on mild winter days but popped in place from late afternoon during periods of sub zero temperatures in the darker days of winter.

I tried your link but dont have a clue how to use it! that's interesting about investing in a wind farm - i didn't know you could do this! can i ask how much you invested in the first place to then only have to pay 2.5p/kwh? 

countryhouse39

ABrass said:

Probably yes.

If you're properly rural then you can go for a large ground mounted array, which should cut down on installation costs and allow you to go as large as you like.

The panels won't generate in the dark (obviously) so they won't cover your use in the mornings to bring the house up to temperature. But I've heard you should run GSHP at a lower level but for a longer time, so it might cover some daytime use in Autumn, Winter and Spring.

The classic challenge is that when you need to heat your house there is the least sunshine.

Solar thermal is mostly a dead end now, PV is so much easier to fit and the price of the panels has dropped off a roof.

thanks  -that's interesting about the solar thermal not being worth it. We are rural, but in a village and while we have a large garden a lot of it has large trees, so i don't think that we could have a ground array. It would have to be on our roof. We have a south facing roof, (house is a long thin L-shape) but the south facing roof is street front and also facing some large trees (not right next to it, but will cause some shade), but we are open to the west.

QrizB

countryhouse39 said:

I tried your link but dont have a clue how to use it! that's interesting about investing in a wind farm - i didn't know you could do this! can i ask how much you invested in the first place to then only have to pay 2.5p/kwh? 

Here's a direct link:

https://re.jrc.ec.europa.eu/pvg_tools/en/#PVP

1. Look at the map. Zoom in to find where you live (more or less) then click on the map to drop a pin.
2. Look at the input table next to the map. The drfaults are for a 1kWp array facing south. You can leave this alone or edit it (I suggest leaving it for now.)
3. Click "visualise results". A summary table and monthly bar chart will appear below. "Yearly PV energy production [kWh]" is how much electricity your array will generate, based on the map and the input table. The chart shows how many kWh per month. All values are averages.
   

What do you get when you try this?

countryhouse39

QrizB said:

countryhouse39 said:

I tried your link but dont have a clue how to use it! that's interesting about investing in a wind farm - i didn't know you could do this! can i ask how much you invested in the first place to then only have to pay 2.5p/kwh? 

Here's a direct link:

https://re.jrc.ec.europa.eu/pvg_tools/en/#PVP

1. Look at the map. Zoom in to find where you live (more or less) then click on the map to drop a pin.
2. Look at the input table next to the map. The drfaults are for a 1kWp array facing south. You can leave this alone or edit it (I suggest leaving it for now.)
3. Click "visualise results". A summary table and monthly bar chart will appear below. "Yearly PV energy production [kWh]" is how much electricity your array will generate, based on the map and the input table. The chart shows how many kWh per month. All values are averages.
   

What do you get when you try this?

I get the below:

Simulation outputs:Slope angle [°]:35

Azimuth angle [°]:

0

Yearly PV energy production [kWh]:

881.59

Yearly in-plane irradiation [kWh/m2]:

1074

Year-to-year variability [kWh]:

44.06

Changes in output due to:Angle of incidence [%]:

-3.28

Spectral effects [%]:

1.85

Temperature and low irradiance [%]:

-3.11

Total loss [%]:

-17.92

countryhouse39

@QrizB i have no idea if the above is good or bad....!