Renewable energy to save money? Sorry It doesn't work.
Discussion
So much wrong in the opening post. This is my area of expertise and I’ve tried in the past to post sensible unbiased facts about renewables, both benefits and pitfalls, but I’m tired with arguing with biased Ill informed people on here.
So here are a few facts.
PV is relatively cheap and at around £4.5k for 4kW installed it would take around 7 years to pay back if you make a little effort to shift some loads like washing machine, dishwasher, etc. to daytime. At current ave electricity prices of 20p/kWh and 8% ave annual price rises it will net a return in excess of £40k in savings over its lifetime, even taking into account panel degradation (10% over 20 years) and a replacement inverter at £300 at 15-20 years old. 12kWh of batteries would add around £3.5k to the cost but will still only take 7 years to pay back and should give lifetime savings in excess of £60k, even taking into account of replacement batteries at 12-14 years old. This is based on savings alone with no FIT or other grant or subsidy.
Heat pumps do not work on the majority of existing housing stock. FACT. They cannot reach a high enough temperature to run radiators effectively on cold days without at least doubling the number or size of rads, you would also need to add much more insulation to walls, floors and ceilings and possibly replace the windows to ensure heat isn’t being lost faster than you can provide. Anyone who is selling heat pumps to replace a mains gas boiler is likely a scammer. It will not heat your 3-bed semi effectively and will be expensive. Even at a COP of 3-1 with electricity at 20p it would be double the price of running a gas boiler, once you get below 7 degrees and the COP drops to 1-1 then it’s 5 times the price of a gas boiler to run!
Heat pumps however are great if the property has been designed from scratch to run at lower heating temps for example a new build with underfloor heating or extra large rads and with modern levels of of insulation. They’re still more expensive to run than a gas boiler would be but that’s not an option going forwards so it’s either heat pumps or electric boiler or panel heaters, both of which are less efficient than a heat pump.
Wind power is great at MW grid scale as can easily be seen when looking at how much energy we actually generate using wind power in the UK but generally not at smaller sizes and definitely not an urban or domestic product. The OP made a few points about the costs to build and maintain turbines but I’m sorry to be the bearer of bad news but £for£ they are by far the cheapest and most reliable way to generate electricity, look at the cost of building Hinckley C and the ongoing maintenance costs of a now closed Sellafield if you’d like a comparative cost
Edited to add Solar Hot Water
Relatively cheap to install although you will need a HW cylinder with a spare coil and not great with a combi-boiler (doable but not an elegant solution) a well designed system should give you free hot water for 7 months of the year and will raise the temp of the cylinder even in winter on sunny days so still saving money. Maintenance costs are pretty low with a glycol check every few years and should easily last 20-30 years without trouble.
So here are a few facts.
PV is relatively cheap and at around £4.5k for 4kW installed it would take around 7 years to pay back if you make a little effort to shift some loads like washing machine, dishwasher, etc. to daytime. At current ave electricity prices of 20p/kWh and 8% ave annual price rises it will net a return in excess of £40k in savings over its lifetime, even taking into account panel degradation (10% over 20 years) and a replacement inverter at £300 at 15-20 years old. 12kWh of batteries would add around £3.5k to the cost but will still only take 7 years to pay back and should give lifetime savings in excess of £60k, even taking into account of replacement batteries at 12-14 years old. This is based on savings alone with no FIT or other grant or subsidy.
Heat pumps do not work on the majority of existing housing stock. FACT. They cannot reach a high enough temperature to run radiators effectively on cold days without at least doubling the number or size of rads, you would also need to add much more insulation to walls, floors and ceilings and possibly replace the windows to ensure heat isn’t being lost faster than you can provide. Anyone who is selling heat pumps to replace a mains gas boiler is likely a scammer. It will not heat your 3-bed semi effectively and will be expensive. Even at a COP of 3-1 with electricity at 20p it would be double the price of running a gas boiler, once you get below 7 degrees and the COP drops to 1-1 then it’s 5 times the price of a gas boiler to run!
Heat pumps however are great if the property has been designed from scratch to run at lower heating temps for example a new build with underfloor heating or extra large rads and with modern levels of of insulation. They’re still more expensive to run than a gas boiler would be but that’s not an option going forwards so it’s either heat pumps or electric boiler or panel heaters, both of which are less efficient than a heat pump.
Wind power is great at MW grid scale as can easily be seen when looking at how much energy we actually generate using wind power in the UK but generally not at smaller sizes and definitely not an urban or domestic product. The OP made a few points about the costs to build and maintain turbines but I’m sorry to be the bearer of bad news but £for£ they are by far the cheapest and most reliable way to generate electricity, look at the cost of building Hinckley C and the ongoing maintenance costs of a now closed Sellafield if you’d like a comparative cost
Edited to add Solar Hot Water
Relatively cheap to install although you will need a HW cylinder with a spare coil and not great with a combi-boiler (doable but not an elegant solution) a well designed system should give you free hot water for 7 months of the year and will raise the temp of the cylinder even in winter on sunny days so still saving money. Maintenance costs are pretty low with a glycol check every few years and should easily last 20-30 years without trouble.
Edited by 4Q on Saturday 5th February 11:03
Edited by 4Q on Saturday 5th February 11:56
4Q said:
Heat pumps do not work on the majority of existing housing stock. FACT. They cannot reach a high enough temperature to run radiators effectively on cold days without at least doubling the number or size of rads, you would also need to add much more insulation to walls, floors and ceilings and possibly replace the windows to ensure heat isn’t being lost faster than you can provide.
This is not actually true any more. R290 based heat pumps are coming in with flow temperatures of 75degrees, so the radiator issue should be resolved and makes retrofit far more cost effective. Doesn't of course mean you should not also insulate properly.Edited by 4Q on Saturday 5th February 11:02
4Q said:
This is my area of expertise.
Heat pumps do not work on the majority of existing housing stock. FACT.
Please don’t state the first followed by such a ridiculous statement, Heat pumps do not work on the majority of existing housing stock. FACT.
Edited by 4Q on Saturday 5th February 11:03
Coming from a true expert you can quote me on the following
Correctly designed and specified Heat Pumps systems work in ANY property, as with ANY heat source they work more effectively & efficiently in well insulated draft free buildings
springfan62 said:
This is not actually true any more. R290 based heat pumps are coming in with flow temperatures of 75degrees, so the radiator issue should be resolved and makes retrofit far more cost effective. Doesn't of course mean you should not also insulate properly.
Yes they are but to achieve 75 deg you a need flow rate which is too slow for most already installed central heating systems so would have to install new pipe work and rads. The issue with high running costs due to low COP especially at cold outside temps still stands for HT ASHP. IIRC most HT ASHP still only have a COP of 2.6-1 at air 7deg and water 55deg so you’re still paying 8p/kWt for electricity if its 20p/kWh vs 5p for mains gas.
brianb said:
Please don’t state the first followed by such a ridiculous statement,
Coming from a true expert you can quote me on the following
Correctly designed and specified Heat Pumps systems work in ANY property, as with ANY heat source they work more effectively & efficiently in well insulated draft free buildings
I went on to qualify that statement later in the paragraph. On the existing heating system with the existing levels of insulation they will not keep your house warm and will dramatically increase your heating costs.Coming from a true expert you can quote me on the following
Correctly designed and specified Heat Pumps systems work in ANY property, as with ANY heat source they work more effectively & efficiently in well insulated draft free buildings
Btw I’m not a plumber who dabbles in a few heat pump fitments alongside my boiler swap and bathroom refits
renewables have been my business since 2003. My company wrote what became the basis of the qualification standards for installers. Are the training provider for one of the worlds largest heat pump manufacturers and have trained many of the uk’s heat pump installers (maybe even you if you did an accredited course) I’ve provided technical support and been expert witness in a number of mis-selling of heat pump cases so yes I consider myself qualified to comment. (Although PV is my real specialism and employ guys far more knowledgable on hp than I am) Edited by 4Q on Saturday 5th February 11:48
So
If your 40y old family member whom you like was having her three bed semi extended, gutted and refurbished, what new tech would you install if they would be there for life (maybe 40-50y)? Nearly south facing garden.
Sounds like you are suggesting:
PV panels
Battery
GSHP or AHSP?
EV charging point that takes daytime PV leccy
Would you suggest an immersion heater that heats the water and takes PV power?
They want to have wet UFH throughout. Just towel rails in the bathrooms with wet UFH in them too.
If your 40y old family member whom you like was having her three bed semi extended, gutted and refurbished, what new tech would you install if they would be there for life (maybe 40-50y)? Nearly south facing garden.
Sounds like you are suggesting:
PV panels
Battery
GSHP or AHSP?
EV charging point that takes daytime PV leccy
Would you suggest an immersion heater that heats the water and takes PV power?
They want to have wet UFH throughout. Just towel rails in the bathrooms with wet UFH in them too.
I don't mind all the tech be it solar panels, inverters, wind generation which all seems to be subsidised by our bills.
The vast majority of these products are made in China made using increasing amounts of coal fired power stations which is then shipped half way around the globe back to us the west, while CCP has slaves forced to work on these and many other products or maybe have their organs harvested or locked up for re-education.
They keep pumping it out and we pay though the nose for it. Dumb!
Unless your in a UK/ Government industry making a killing off the subsidies.
The vast majority of these products are made in China made using increasing amounts of coal fired power stations which is then shipped half way around the globe back to us the west, while CCP has slaves forced to work on these and many other products or maybe have their organs harvested or locked up for re-education.
They keep pumping it out and we pay though the nose for it. Dumb!
Unless your in a UK/ Government industry making a killing off the subsidies.
MrJuice said:
So
If your 40y old family member whom you like was having her three bed semi extended, gutted and refurbished, what new tech would you install if they would be there for life (maybe 40-50y)? Nearly south facing garden.
Sounds like you are suggesting:
PV panels
Battery
GSHP or AHSP?
EV charging point that takes daytime PV leccy
Would you suggest an immersion heater that heats the water and takes PV power?
They want to have wet UFH throughout. Just towel rails in the bathrooms with wet UFH in them too.
4kW PV (3.68 inverter) & Battery sized to one days consumption excl the heat pump. The PV will provide no meaningful power a heat pump as I need heat when I don’t have solar. Sizing batteries to power the hp from cheap off peak would be cost prohibitive. If your 40y old family member whom you like was having her three bed semi extended, gutted and refurbished, what new tech would you install if they would be there for life (maybe 40-50y)? Nearly south facing garden.
Sounds like you are suggesting:
PV panels
Battery
GSHP or AHSP?
EV charging point that takes daytime PV leccy
Would you suggest an immersion heater that heats the water and takes PV power?
They want to have wet UFH throughout. Just towel rails in the bathrooms with wet UFH in them too.
Mains gas if you have it but if not GSHP as the performance is much better in cold weather than ASHP although capex is much higher.
I’d add Solar Hot water panels with immersion as back up.
I wouldn’t try and charge the EV from the PV as mostly it won’t generate enough to make a difference unless I’m using all my generation meaning I can’t save money of my regular consumption, especially as I can already buy cheap rate electricity overnight to do that
Edited by 4Q on Saturday 5th February 12:08
souper said:
I don't mind all the tech be it solar panels, inverters, wind generation which all seems to be subsidised by our bills.
The vast majority of these products are made in China made using increasing amounts of coal fired power stations which is then shipped half way around the globe back to us the west, while CCP has slaves forced to work on these and many other products or maybe have their organs harvested or locked up for re-education.
They keep pumping it out and we pay though the nose for it. Dumb!
Unless your in a UK/ Government industry making a killing off the subsidies.
There are no subsidies any more, the CC levy on your bill is another stealth tax and does not go directly towards any subsidies. The carbon footprint of PV production is around 3 years iirc, the carbon and energy savings last 30 years plus.The vast majority of these products are made in China made using increasing amounts of coal fired power stations which is then shipped half way around the globe back to us the west, while CCP has slaves forced to work on these and many other products or maybe have their organs harvested or locked up for re-education.
They keep pumping it out and we pay though the nose for it. Dumb!
Unless your in a UK/ Government industry making a killing off the subsidies.
The dirty generation and terrible working conditions unfortunately apply to pretty much everything you own which was produced in China and other 3rd world economies. If you’re posting from a tablet or phone some the components in that are some the worst offenders.
Edited by 4Q on Saturday 5th February 12:06
Edited by 4Q on Saturday 5th February 12:09
4Q said:
So much wrong in the opening post. This is my area of expertise and I’ve tried in the past to post sensible unbiased facts about renewables, both benefits and pitfalls, but I’m tired with arguing with biased Ill informed people on here.
That's exactly why I started this thread we'll archive it so you don't have to do it again and again every week.Please put forward your facts and hopefully a current real life example which has proved you to be correct.
I only want you do do it once and do it properly.
TooLateForAName said:
Solar is working for us.
I DIY installed some panels on an outbuilding. Panels bought 2nd hand at £50 each. 6 of them up at the moment. Inverter bought cheap £90.
Says its generated 996 kwh so far (about 2 yrs) I've bought one of those smart diverter things so instead of exporting it will run the immersion heater.
My parents do very well out of solar - they covered their roof when the high level of payment was available so they're coining it.
Your first example proves my post to be correct. Your second one is totally lacking in facts so is meaningless.I DIY installed some panels on an outbuilding. Panels bought 2nd hand at £50 each. 6 of them up at the moment. Inverter bought cheap £90.
Says its generated 996 kwh so far (about 2 yrs) I've bought one of those smart diverter things so instead of exporting it will run the immersion heater.
My parents do very well out of solar - they covered their roof when the high level of payment was available so they're coining it.
4Q said:
4kW PV (3.68 inverter) & Battery sized to one days consumption excl the heat pump. The PV will provide no meaningful power a heat pump as I need heat when I don’t have solar. Sizing batteries to power the hp from cheap off peak would be cost prohibitive.
Mains gas if you have it but if not GSHP as the performance is much better in cold weather than ASHP although capex is much higher.
I’d add Solar Hot water panels with immersion as back up.
I wouldn’t try and charge the EV from the PV as mostly it won’t generate enough to make a difference unless I’m using all my generation meaning I can’t save money of my regular consumption, especially as I can already buy cheap rate electricity overnight to do that
I do have mains gas. Are you saying I should have a gas boiler and a heat pump?Mains gas if you have it but if not GSHP as the performance is much better in cold weather than ASHP although capex is much higher.
I’d add Solar Hot water panels with immersion as back up.
I wouldn’t try and charge the EV from the PV as mostly it won’t generate enough to make a difference unless I’m using all my generation meaning I can’t save money of my regular consumption, especially as I can already buy cheap rate electricity overnight to do that
Edited by 4Q on Saturday 5th February 12:08
Would solar be heating my hot water in addition to charging my battery? Or one or the other? Do I need to have a gas back up in addition to the immersion?
Rough cost of installation of PV on my roof (there'll be 1.5 times the roof space of a typical London 1930s semi), plus battery plus whichever heat pump has shortest payback? Please?
Plus, can consumers opt to go on to peak and off peak energy? Do they have to foot the bill for changeover of meters or can this be done through a smart meter?
(When I moved in in 2017, there were off peak and peak meters which I had changed to a single digital meter. Not sure if smart meter (don't think it is))
Thank you
Evoluzione said:
Air or ground source heat pumps
Are currently being partly financed by a government grant making them at least, interesting.
Ugly
Noisy
The heat they create is quite mild. This means you'll need a very, very well insulated (modern) house and need to put in suitably (large) sized radiators or underfloor heating to make use of it.
They make the least heat when you need the most (in Winter).
I'm thinking servicing costs could be quite low due to the small and basic moving parts and some R-410A refrigerant gas, but don't quote me on that.
Edited by Evoluzione on Saturday 5th February 11:24
Not only did I get £10k grant to install, but I'm being paid nearly £6k over 5 years towards the electricity saved.
Just reading the post below, the grant was EST and the ongoing payments are RHI. (I am in Scotland, so don't know what happens down south).
Edited by GetCarter on Saturday 5th February 12:27
I do have mains gas. Are you saying I should have a gas boiler and a heat pump?
Stay on mains gas it would have to see a 5 fold increase to be the same price as electricity, even with a heat pump.
Would solar be heating my hot water in addition to charging my battery? Or one or the other? Do I need to have a gas back up in addition to the immersion?
Separate panels, separate system.
Rough cost of installation of PV on my roof (there'll be 1.5 times the roof space of a typical London 1930s semi), plus battery plus whichever heat pump has shortest payback? Please?
Approx £4.5k fitted for PV + £3.5k for 12-14kWh of batteries as quoted previously, obvs not included London tax as things like higher labour and scaffolding costs could easily add another £1000.
Plus, can consumers opt to go on to peak and off peak energy? Do they have to foot the bill for changeover of meters or can this be done through a smart meter? smart meter will meter peak/off peak
Stay on mains gas it would have to see a 5 fold increase to be the same price as electricity, even with a heat pump.
Would solar be heating my hot water in addition to charging my battery? Or one or the other? Do I need to have a gas back up in addition to the immersion?
Separate panels, separate system.
Rough cost of installation of PV on my roof (there'll be 1.5 times the roof space of a typical London 1930s semi), plus battery plus whichever heat pump has shortest payback? Please?
Approx £4.5k fitted for PV + £3.5k for 12-14kWh of batteries as quoted previously, obvs not included London tax as things like higher labour and scaffolding costs could easily add another £1000.
Plus, can consumers opt to go on to peak and off peak energy? Do they have to foot the bill for changeover of meters or can this be done through a smart meter? smart meter will meter peak/off peak
Edited by 4Q on Saturday 5th February 12:48
What we need for renewables is a fair export price for exporting surplus energy, then we can all install PV panels and export the surplus to the grid and be paid a fair price.
At the moment thew SEG is something like 5p so the electricity supplier buys it off you for 5p and sells it to someone else for 30p per kWh.
Something like Octopus Agile Outgoing pays 15p roughly at the moment for surplus pv, it makes it far less attractive then to export than to purchase batteries. It's a shame there are not more schemes like this.
At the moment thew SEG is something like 5p so the electricity supplier buys it off you for 5p and sells it to someone else for 30p per kWh.
Something like Octopus Agile Outgoing pays 15p roughly at the moment for surplus pv, it makes it far less attractive then to export than to purchase batteries. It's a shame there are not more schemes like this.
caziques said:
Evoluzione said:
Air or ground source heat pumps
Are currently being partly financed by a government grant making them at least, interesting.
Ugly
Noisy
The heat they create is quite mild. This means you'll need a very, very well insulated (modern) house and need to put in suitably (large) sized radiators or underfloor heating to make use of it.
They make the least heat when you need the most (in Winter).
I'm thinking servicing costs could be quite low due to the small and basic moving parts and some R-410A refrigerant gas, but don't quote me on that.
Noisy - modern inverter units don't make much noise.
"The heat they create is quite mild". No, the greater the temperature difference to pump through, the lower the efficiency. Hence big radiators run at lower temperatures meaning lower running costs - which is why underfloor is so good with a heat pump. Maximum water temperature is 35.
If a heat pump system has ferrous materials it will need water treatment every couple of years. Get rid of ferrous, and there is minimal maintenance.
A hot water heat pump itself does not need servicing, only cleaning.
They do make a noise. This won't be a problem in Winter when they are needed the most and in Summer when you're sat outside i'm presuming they won't be running (if all they are doing is heating the house), but don't honestly know that.
They do have a long life too, circa 25yrs which is a major plus point.
A max temp of 35'c is mild, it is not hot hence the need for UFH or radiator upgrade.
You also need a lot of land and for it to be dug up to lay the pipes in.
When they are needed the most (the colder it gets) they put out the least amount of heat. If the temp drops below 4 then you're actually paying more to run the thing than it pays you back in heat so you're in minus figures. So you need to factor in the cost of an additional heating system to help it through these periods.
GetCarter said:
Evoluzione said:
Air or ground source heat pumps
Are currently being partly financed by a government grant making them at least, interesting.
Ugly
Noisy
The heat they create is quite mild. This means you'll need a very, very well insulated (modern) house and need to put in suitably (large) sized radiators or underfloor heating to make use of it.
They make the least heat when you need the most (in Winter).
I'm thinking servicing costs could be quite low due to the small and basic moving parts and some R-410A refrigerant gas, but don't quote me on that.
Edited by Evoluzione on Saturday 5th February 11:24
Not only did I get £10k grant to install, but I'm being paid nearly £6k over 5 years towards the electricity saved.
Just reading the post below, the grant was EST and the ongoing payments are RHI. (I am in Scotland, so don't know what happens down south).
What would be the total installation cost for the majority of us in our average houses? Your price should include:
Insulating the house adequately
Replacing existing rads or putting in new UFH.
The cost of those two alone is more than the grant itself.
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