UKC

Our gas boiler is on its last legs. It's 20 years old and struggling in the cold. I need to make a decision on what to do next. We'll keep it limping along for now, but need to plan for a change.

Talk about heat pumps seems to generate strong opinions but not many objective facts. Maybe because they're too new. I can't find many balanced sources of information but they might not suit my house - it's old and listed and about 200 square metres, though we have space for air- or ground-source outside.

Or gas boilers - The current one is a bit weedy for the house - we have a hot water tank and radiators at the far end of the house that don't really work. And if we go gas and tie ourselves into fossil fuels for the next 15 years, who knows what the bills will be then.

So options seem to be a big gas boiler, some sort of hybrid system or a big pump and potentially some planning issues with the listing.

Anyone had any similar problems? What's your next heating move?

In reply to compost:

It's a difficult world to navigate, especially as most people in the industry have a vested interest in selling a product, whether it's right for you or not. Getting advice from strangers on the internet must carry the caveat that we are just strangers on the internet.

Luckily for you Historic England has just released some updated guidance on heat pumps in historic buildings: https://historicengland.org.uk/advice/technical-advice/retrofit-and-energy-...

They also had a 'Technical Tuesday' webinar on the topic today which was recorded and will be posted on their website soon.

If it turns out that heat pumps aren't for you there are other electric options. One that looks good to me is this: https://tepeo.com/. Essentially a central storage heater. It plugs in to your existing plumbing and charges up at night with a cheap time of day tariff.

In reply to compost:

What's your budget?

If you need some warmth fast for <£3-4k, then new gas is the only option really. If you have £10-15k to throw at it and want something slightly more future proof, get a decent ASHP or GSHP (maybe nearer £20k for the latter), plus the associated improving your insulation, bigger rads and/or UFH etc to make it actually work. It does need to be designed properly and there are a lot of clueless installers around, so be careful before committing.

You could look at biomass/woodchip boilers perhaps, if you have a decent supply and space to store it. I don't know much about them though. That should be reasonably compatible with your existing plumbing at least.

In reply to NobleStone:

Thanks both - really helpful. This is why strangers on the internet are great - not trying to sell me their latest and greatest but a much broader perspective!

I'll look at those link.

On budget, tbh I'm looking at it as total cost of ownership, not just the initial capital outlay. If I can make the case that ground source is cheaper over, say, 15 years, I'm interested.

In reply to compost:

I'm in a similar position to you with a gas boiler on its last legs and a big badly insulated house. I'm also an engineer who designs sustainable buildings for a living.

In an ideal world I'd insulate to passivehouse standard and get an air to water heat pump like the daikin altherma. However the reality of insulating a 1850 building without trashing it's character precludes this. I've looked at the flow temperature and corisponding CoP data and radiator power outputs from the low temperature heat pump at 55 dg flow and there is no way it will warm the place up.

I've looked at high temperature CO2 refrigerant heat pumps. These theoretically give as high a SCoP performance as the low 55 deg flow temperature heatpump option above but with 75 deg flow temp could work with sensibly sized radiators in an old building. However, whilst we are specifying these for the DHW in the new generation of Net Zero Commercial buildings, I can't find anyone willing to install one in my house.

I've looked at a VRF multi split system. This is widely used in small non-residential design, but do come with some fan noise issues from the room units. Again struggling to find anyone who wants to do a design and install in an old, difficult access, residential project.

I'm 100% not looking at electric heating as the annual operational cost of it is ridiculous. 

I've got someone coming to talk to me about biomass pellet boilers and log gasification units tomorrow. If I don't like them I'm replacing the gas boiler like for like and saving up for a big refurbishment where I do the insulation.

Good luck with your search.

In reply to compost:

I have been considering the same dilemma. Heat pumps aren’t really new technology, I believe that they have in use in domestic properties for around 40 years, they just have never been very popular in the UK which means that radiators aren’t typically sized to use them and installers don’t have as much experience as with gas. You can find no end of people complaining that their pumps don’t work as advertised, never get to temperature or cost an absolute fortune. My understanding is that this is often down to poor installation or incorrect usage but making sure that yours is sized and installed correctly looks like a minefield.

What I am tempted to do is go with an air to air heat pump for heating the 3 bedrooms and 2 living areas in the house, see below:

https://www.daikin.co.uk/en_gb/product-group/air-to-air-heat-pumps/multi.ht...

And then go with the below heat pump/hot water tank combo for hot water and the bathroom radiator and the radiator in the porch/hallway if I decide that it is necessary to heat that:

https://groundsun.co.uk/small-home-and-apartment-heat-pumps/

I think that this should be a fairly robust and easy to use system with no need for huge radiators in every room. I haven’t got a price for this and annoyingly I think that it would not be eligible  for any grants.

I would be interested to know if anyone thought that there was a flaw in setting the heating up like this?

In reply to S Ramsay:

The flaw may be finding someone skilled to do the install. I've been struggling to get anyone interested in doing a multi split design in my house.

I've contacted dozens of installers in the Central Belt with no interest.

Also have you considered the acoustic impact of the fan noise? I wanted to do a re-circulation duct based system in the roof void to avoid the noise of fans in bedroom.

In reply to S Ramsay:

I don't think there are any grants for air-to-air heat pumps. (VRF split systems) This is possibly as they also do cooling and this is being strongly discouraged at the moment to avoid all the heating energy savings being swallowed up by summer cooling energy.

In reply to Brown:

I can only imagine the angst when you get home from work :-D

This is the type of calc I need to be doing but don't know where to start - any helpful tips on online calculators?

In reply to compost:

I'm an ex-builder and have decided to replace a gas boiler like-for-like as I don't want to destroy the character of the building through applying insulation

There is some good info on the link below if you decide to upgrade the insultation on your house ahead of some sort of heat pump installation

https://historicengland.org.uk/images-books/publications/eehb-how-to-improv...

In reply to compost:

Check the energy rating of your house and consider a survey to verify it. You will likely need considerable extra insulation and work to seal drafts etc to make a ASH viable. 

Do this up front to aid your decision

In reply to compost:

If mine failed today I'd be going with one more gas boiler.  10 years or so (the typical reliable lifespan of one) is probably about the right period of time for the benefits and pitfalls of alternatives to become clear for next time.

It will also become more clear as to what future electricity use is like, in particular with regard to the storage solution someone mentioned.  With increased numbers of EVs overnight may not be off-peak any more, with usage more consistent all day and night, and as such Economy 7 and the likes may vanish.

In reply to compost:

https://www.stelrad.com/wp-content/uploads/2018/05/The-Stelrad-Specificatio...

page 42 shows the adjustment to radiator outputs at varying flow temps. Traditional systems were set up to run at 75 / 65 giving about a 50 degree difference between the target room temperature and the radiator water.

Standard air to water heat pumps have good efficiencies when producing low temperature hot water in the 55 / 45 or lower range. If you drop the radiator temperature down by that much you reduce the radiator power output by 50%. To over come this you may need to leave the heating on all the time to avoid the long warm up period or increase the flow temperature. If you heat the water hotter the efficiency drops of badly and they begin to look like standard electric heating. Both are bad for your operational cost.

There are lots of online radiator sizing tools to work out the required power output in kW to warm rooms and the maths is quite basic.

In reply to Brown:

I run both pellet and wood gasification central heating (either one or the other or both combined) and have long planned to fit an air-water heat pump to provide base load feed of ca 35° and let the others jump in to get the temperature up. Until now the relative price of firewood to electricity here in Germany has been discouraging but age and laziness is slowly tipping the balance!

In reply to compost:

I had to make a similar decision 2 years ago. Stone built, grade II listed, badly insulated 3 bed house.  When we bought it most heating was electric, ferociously expensive to run and not very effective. One room had a log burner.

I wanted to go with a more environmentally friendly heating solution and got quotes for ASHP. Even the people selling the system were doubtful it would be appropriate, anyone I spoke to without a vested interest was adamant we should steer clear.

End-result.  Oil fired boiler and an additional log burner.  I'm adding as much insulation as I can, but from a practical point of view there is a limit.  I still wish I had been able to find a more environmentally friendly solution, but I'm also reasonably confident that we chose the most appropriate overall solution.

In reply to Sam W:

I think the other option will be multi-split systems. It just seems that nobody is really set up to fit into a domestic setting yet.

And people will just get over some fan noise. If it is significantly cheaper than oil that will help.

In reply to jimtitt:

How have you got on with the two boilers? 

I like the automation of the pellet boilers and have now spoken to several non-domestic clients with them who like them. They have packaged plant rooms with multiple units sat in their car parks. The multiple units seems to get rid of reliability issues.

Has the pellet boiler had feed issues?

What do you burn in the log one. I only have access to free/cheap softwood and I hear they may struggle with that. I've never bought logs but think they appear costly.

In reply to Brown:

The only problems are if I don't clean the actual burner cup every month or so, the air flow is reduced and loses flame. It's only a couple of minutes to do it though. The feed screws can have problems with wood-dust buildup, some hoppers have a system you can clean it out occasionally, mine is self-made but has a slide-out drawer for this. I look once a year at it.

I burn everything in the gasifier, plenty of old barns gone through it, otherwise just pine/fir trees, ash or whatevers to hand, for ten years I had a screwed-up wood across the road which I felled but that's gone so I buy in. The quantities to be moved and stored are not to be underestimated!

In reply to compost:

I think that heat pumps can only work as part of an holistic approach to house heating and ventilation. Personally, I no longer believe they are a viable option in most houses as a replacement for an old gas system. Even newer buildings with a cavity wall. 
 

The whole house needs to be insulted to a very high standard and the heating system and ventilation design needs to be specifically designed for accommodation of a heat pump. 
 

They might have been a nicer idea when electric prices were very low, so the system could be running all the time, but with the prices the way they are now I wouldn’t be looking at a heat pump unless I was in a new building with the highest spec insulation and windows, and a very low heat demand.

In reply to compost:

About 4 years ago we changed our 15 year old gas combi boiler to an upto date one. Its breathtakingly efficient compared with the older one.Our bills dropped dramatically and was well worth the investment.

IMHO its just a bit too early to go for heat pumps etc, all this technology its just a bit too unclear about which way too go. We also had a rolling progrmme of getting rid of old radiators.Again worth the money.

Ours is a big old house.

In reply to ogreville:

I think the use of heat pump, to only mean an air to water heat pump, attached to a traditional wet radiator or underfloor heating system is misleading.

Low temperature, air-to-water heat pumps, do only work well with houses with low heat loss.

VRF air-to-air heat pump systems can provide huge output and can be sized to heat even the leakiest dwellings at high efficiencies. These can provide really big power outputs that allow quick warm up periods and are suitable for old dwellings.

Using my current electricity prices I need  a System CoP of >3 to deliver cheaper heat into my house using electricity than a gas boiler and radiator system. These systems are achieving in excess of 4.

(obviously taking a fabric first approach to reducing heat demand is optimal. Using a massive heating system to heat a leaky building is expensive no-matter what system you use. Using a huge air-to-air heat pump is cheaper than a huge gas boiler or oil boiler though.)

In reply to ogreville:

I know a couple of people who've had ASHP retrofitted recently (70s and 00s houses, single phase, nothing special insulation wise). In both cases the plumbing was largely preserved but the rad's upgraded. Both very pleased with warmth. One of them very pleased with much cheaper bills (vs off grid oil), the other too newly converted to say but he's pleased his solar panels are now heating his house when they'd otherwise previously have been working for someone else.

In both cases the capital outlay was high, they're older/retired professionals able to invest.

I really don't get what people have against heat pumps, what's not to love about 300+% efficiency! Making them work properly is an engineering job like the central heating system they replace was once. Making them affordable is about growing volume (product and installer expertise) and removing stop-start government market distortion.

jk

In reply to jkarran:

Because they are not 300% efficient in energy terms , power stations and supply are inefficient to begin with.

In reply to jimtitt:

So are gas boilers. Less so than a good modern gas power plant but not by that much. Something like 92% for a modern condensing boiler vs something like 64% for CCGT electricity, multiply that by a reasonably modest CoP of 3 for a heat-pump and you're comparing 92% efficiency against 192%, energy-in/heat-out, still a significant win over simply burning the gas locally. If we're looking at heat/CO2 ratio then the situation is better still since a significant fraction of our electricity on normal days is from nuclear and renewables.

jk

In reply to jkarran:

As I understand, they are only 300% (sometimes 400%) under ideal conditions. I.e., warm conditions.

The problem is, we don't rely on our heating very much in ideal conditions.

When the temperatures reach zero degrees, the efficiency (as I've read, not first hand experience) drops to 200%, and continues to drop as the air temperature outside reduces into the minus.

So you get lower efficiency when you need to use the heating system the most.

Then you need to compare the electric price at 34p per KWH vs gas at 10 (I think these figures are up to date).

So a modern efficient gas boiler is likely cheaper to run (slightly) and obviously way cheaper to buy and install.

Money no object, I would go with a massive battery bank, get an EV tariff, charge the battery during the day and run and air or ground source heat pump off the battery.

Not only is this the greenest option, it's the cheapest to run as you'll get 10p per KWH at night. If you average an efficiency of 250%, then it's 2.5X cheaper to run than a gas boiler. ground source would be even better.

Expensive to set up however.

Question is, will EV tariffs exist in the future? When everyone has EVs the equation may change and suppliers might not be able to offer the cheaper rate anymore.

In reply to compost:

Sliced Bread (BBC Sounds) had a pod cast on ASHP that I learnt a lot from

In reply to jkarran:

You are also allowed to calculate the efficiency by cost, as in the post above!

And a COP of 3 looks good on paper as it is a laboratory value, in a long-term survey of a number of installation in low-energy newbuilds in Germany the actual value for the complete systems (air-air) averaged 2.6.

The "actual" efficiency is calculated by taking the seasonal COP's (SCOP's), weighting them for the differing amounts of use then dividing by the primary energy factor which for Europe is 2.5. An SCOP for example of 3 gives an efficiency of 120%.

In reply to compost:

Some good real-world information from this chap on YouTube, he's pretty transparent about performance and costs in his old stone house: https://www.youtube.com/watch?v=WuAunibSIoA&t=47s

(He has also done a video during this week's cold snap to show how it's doing)

It could be that an interesting old house needs a more interesting/bespoke solution than holding out for one silver-bullet technology.

Some ideas: (spit-balling here, just suggestions, not fully formed solutions)

• Treat the central heating and hot water as separate systems that you can pick the best devices for. (As you said, some sort of hybrid system)
• Could use heat pump, or electric/storage equivalent like tepeo*, for central heating.
• Then use an Eddi or Mixergy for hot water, to access off peak pricing or PV self-consumption.
• If distant parts of the house are straining the CH loop and decreasing efficiency, you could take them off the loop and use local heating like IR panels or Electric skirting board, as needed.
• Any insulation you can add will make whatever solution you end up with better.
• There are loads of interesting and modular options before giving in to another gas boiler, might be worth speaking to someone like Heat Geek, Ecobubl, Your Energy Your Way, or similar.

*Some have said off-peak tariffs won't stick around, I disagree. Devices like this, including EV charging, will provide the grid with so much flexibility and demand-side response that time-of-use pricing is likely to increase in variety and availability, not disappear.

In reply to Brown:

Classic ‘do as I say - not as I do’ example 😆

In reply to thread:

Lots of suggestions and ideas in this thread. But how is the average person, living in whatever house they happen to be living in, supposed to get proper advice about how best to proceed, in what could be a fiendishly expensive business? It all seems very unsatisfactory.

In reply to George Killaspy:

Thanks all - some brilliant useful suggestions

In reply to Rob Parsons:

100% this - I came here for advice for exactly that reason. 

In reply to jkarran:

I think it's due to well-publicised early adoption failures, and a failure to understand the limitations. For example, I know of someone who installed a GSHP and literally froze their garden and killed all the vegetation because the load was too great for the ground loop.  The low output temp requires a large radiator area and people mis-calculated that side of the equation, thus saw poor performance.  A well-engineered system should have no problems.

In reply to Rob Parsons:

I asked the OpenAI ChatGPT the following question for an unbiased asnwer.

Q: "I live in the UK. Should I replace my broken gas boiler with a new gas boiler or replace it with an electric heat pump? I want to lowest whole life cost."

A: "When deciding whether to replace a broken gas boiler with a new gas boiler or with an electric heat pump, it is important to consider the whole life cost of each option. The whole life cost takes into account not just the upfront cost of the equipment, but also the ongoing operating costs and maintenance costs over the life of the system.

In general, electric heat pumps tend to have a lower whole life cost compared to gas boilers, especially in cases where the cost of natural gas is high. This is because heat pumps are generally more energy efficient and have lower operating costs. However, the specific cost savings will depend on a variety of factors, including the size and type of heat pump, the size and type of gas boiler, and the local cost of electricity and gas.

To determine the lowest whole life cost for your specific situation, it is a good idea to consult with a heating and cooling specialist and get quotes for both options. They can help you compare the costs and determine which option is the most cost-effective for your needs. It is also a good idea to consider any government incentives or rebates that may be available to help offset the upfront cost of installing a new heating system."

I think it's answer is wrong that a heat pump is cheaper to run than a a gas boiler. Plus they are definitely more expensive to buy and maintain. Bad OpenAI. Well written answer however.

In reply to montyjohn:

An AI bot won't help us - it will require expert individual analyses of individual houses.

In reply to Rob Parsons:

Well ye, but it's interesting nevertheless.

In reply to montyjohn:

Yeah, I wasn't trying to pooh-pooh the entire idea - it could have value for standard, unmodified. modern housing stock. But analyzing the options for the overall historic mess of British housing will require a completely bespoke approach. It's not an easy problem.

In reply to Rob Parsons:  My mate has just emarked on an expensive house renovation/extension and an ASHP system.

I'm reserving judgement until I've seen how it performs for at least a year.    

In reply to montyjohn:

How about environmental cost? Almost all of these discussions focus on financial cost.

Cheap gas should be treated the same as cheap petrol or cheap aviation fuel. 

In reply to artif: But a new condensing gas boiler and control system will burn a lot less gas compared to the old boiler. The carbon benefits of heat pumps always use the average emission factor for UK electricity. However with the UK’s current and medium term generation mix when a heat pump starts up it doesn’t result in a dormant wind turbine spinning up, they will always produce as much as they can. Instead a 40% efficient gas fired power station will load up. 40% efficiency x heat pump seasonal COP of 2.5 = 100% net efficiency. A well installed and controlled condensing gas boiler should be 90% efficient. An old gas fired boiler may be 55% to 60% efficient. The new gas boiler is the most cost effective way of reducing carbon emissions 

In reply to kevin stephens:

You have a choice in who you pay for electricity, I know it goes in the same pot, but if gas powered suppliers don't get the money they won't run.

Electric heating is 100% efficient

Burning gas is not a long term solution

The title of thread asks about "long term" after all. 

In reply to kevin stephens:

Sorry, but this is untrue. You are conflating conversion efficiency with carbon emissions. (And comparing high-grade electricity production with low-grade heat generation)

The UK electricity mix has a lower gCO2/kWh than a gas boiler running efficiently.

A gas boiler produces 215g CO2 per kWh of heat.

A direct electric radiator produces 207g CO2 per kWh of heat. A heat pump can offer heat with as little as 50–100 g/kWh.

These figures are from a 2019 report by Drax, hardly the bastion of eco-consciousness. https://www.drax.com/wp-content/uploads/2020/02/200207_Drax_19Q4_Report_3.p...

In reply to artif:

So during the recent windless cold snap where do you think the marginal electricity came from when you switched on your cooker or washing machine?

In reply to George Killaspy: what you say is correct on AVERAGE emission factors which is what are used for reporting. However the real world marginal impact of switching on or off electrical appliances on UK generation will be to load or unload the gas fired generation that tops up the output of nuclear and renewables

In reply to kevin stephens:

Of course, the average CO2 load for UK electricity for the last 24hrs was 273g/kWh, using an annual average and applying it to something seasonal is bonkers.

In reply to jimtitt:

Well, yes, but so is using a 24 hour average to something that you won't run 24 hours a day.  At this instant (8am Saturday) it is sunless and windless, but the UK grid is currently operating at 183g/kWh. 

My heat pump has been warming my thermal store since 0030 this morning.  Now the CO2 intensity starts to rise (as we bring more CCGT online to cope with the morning pickup) I'm switched off and running on what's stored in that TS.  I won't need to reheat it until my PV is well up and running.

If you don't have heat (or battery) storage or PV then you do have to run your heat pump at time of need, but the best way to install a heat pump is with all these elements combined. And even a standalone heat pump will do the bulk of it's work outside of the highest CO2 intensity periods. 

(This is why we need the smart meter rollout - it's not really about meter readers but actually to allow time-of-use tariffs to encourage usage at lower intensity periods)

Also, probably much more importantly, the gas boiler will remain at 215g/KWh for the rest of its working life.  The UK grid is getting better every year.  If good old Dave hadn't cut the green crap, then we'd have tons more renewables on our grid already and the 273g/kWh for the last 24 hours would be significantly lower.

In reply to kevin stephens:

I know quite well where it comes from, having worked in power generation for many years. Obviously you didnt read my post correctly, as I stated previously, I know all power generators feed in to the same grid. 

As I also said, not giving your money to the gas users makes it financially unsustainable. It's not a difficult concept to understand, a couple of minutes of web searching gets you plenty of green suppliers

In reply to artif:

The fact is that your green energy supplier will have bought power from gas fired power stations over the last week, giving them some of your money. Over a 12 month period they will sometimes have bought surplus of wind generated electricity above the needs of you and your fellow retail customers. They will sell this surplus to other wholesalers. Over the 12 months this will balance out their purchase of gas generated power so they can claim to be carbon neutral. Of course those wholesalers buying the surplus wind power may also claim to be greenish but that would be double accounting. 
It’s great that the UK has a large and growing base of wind generation (helped by your commitment to buy its output). But this is only viable because of lots of gas generating capacity is on standby to replace or top up wind power on less windy or windless days. The technology for large scale LONG TERM storage of surplus wind power does not exist. If we had a lot more nuclear capacity instead of gas then there would be no incentive to invest in wind as nuclear (unlike gas) costs the same whether at full output or standby

In reply to Jamie Wakeham:

Why doesn't your thermal store fill in the day using your PV rather then importing power from God knows where?

As we can see there's no simple answer at least in the medium term, it's not as easy as just change from gas to a heat pump at least for the great mass of housing and buildings.

In reply to Jamie Wakeham:

It may be windless where you are but according to http://www.gridwatch.templar.co.uk/ the Uk is now (9:30 am Saturday) getting 31.5% of electricity from wind marking the end of the recent calm weather.

Your domestic energy strategy is excellent, but hardly practicable or viable for the bulk of UK housing

In reply to jimtitt:

Indeed. The most important and cost effective strategy is to reduce energy use before embarking on costly energy substitution strategies, which would be counter productive and impracticable without massive increase in non-fossil fuel generation and also massive reinforcement of national and local electricity distribution networks. There is massive scope to reduce energy use by UK industrial and domestic energy users. This will in itself achieve substantial savings in CO2 emissions and also ease the burden of transition

In reply to jimtitt:

It does.  On cold days like these the heating part of the TS is exhausted by mid morning, and then it switches the ASHP back in to re-heat it on PV.

It's not really 'god knows where', though.  We can look up where the UK power is coming from at any given moment.

From a pure CO2 perspective I'm (usually) doing better by recharging the TS at night then in the middle of the day.  In the daytime there's plentiful other use for my PV, so I am in a sense depriving the grid of my PV contribution by self consuming it.  As the PV and wind capacities increase we will see more periods in the middle of the day when there is no fossil fuel power in the grid but they're still few and far between.

Installing my system has been expensive and disruptive, no doubt, and not every house would work like mine.  But an awful lot of houses could.  On the very affluent estate I live in, there are 27 more or less identical houses; mine is the only A rated and the only heat pump.  At least two neighbours have had new gas boilers put in over the last few months, and one of them explicitly said that they 'just couldn't be bothered' to look into renewable options.

That it is legal to build a new house in the UK with crap insulation and a gas boiler is just bonkers.

In reply to kevin stephens:

True - wind is up and rising this morning.  But looking back at the grid intensity for the last week, it's still dramatically lower overnight. See the 'this month hourly' graph here - there's a significant dip every night.  https://gridwatch.co.uk/co2-emissions

In reply to compost:

A number of competing goals here.

Old and listed - this is potentially going to tie your hands somewhat

Might be worth getting an infrared thermometer to see how hot each radiator is on a cold day - is provided them low temperature water going to be a solution or is your need for hot water (which is a problem for heat pumps, efficiently)

Can you adjust your heating so that it runs on low temperature constantly rather than hot cold cycles. This might need better controls than you have but if so could lead you back towards a heat pump.

Can you insulate more and can you do so without making a damp problem in future. I.e. probably no modern materials, all breathable stuff 

Heat pumps love low temperature constantly, so if you can adjust your house and your lifestyle to allow that then they could be a good option.

That said, you need to know someone you can trust who knows what they are doing, that is the hard part!

In reply to Jamie Wakeham:

That may be changing.

https://mobile.twitter.com/ScotParl/status/1603687611792515073

A "Scottish equivalent" of Passivhaus but not yet clear what that will mean.

In reply to Jamie Wakeham:

And there's the problem with using blanket annual averages, replace a gas heating with a heat pump and there is extra load on the grid and this has to be covered by either firing up a reserve power station and/or importing which at the moment means that extra power is coming from something far worse in CO2 emissions than a gas boiler. Right at the moment Germany is pushing power at full speed into it's neighbours and even though most of our CHP gas plants are extremely efficient they still still chuck out about 600g/kWh, the coal-fired ones keeping the French warm about 2700g/kWh.

Our minster was going to ban installing new gas heating and make HP compulsory until someone did the sums on a beer-mat, that plan is shelved for the moment.

In reply to jimtitt:

That's the same government that tried to panic shutdown their entire nuclear capability, right? I'm not sure I have all that much faith in their planning!

Heat pumps alone are not the answer. But they are certainly part of it.  So is nuclear, and a whole lot more renewables, including the hydro and tidal that can help when wind and solar are struggling, and much more storage. We will still need gas for quite some time to come.

In reply to elsewhere: when I was advising the Scottish Government on an upgrade to the energy efficiency provisions of the Scottish Building Regs around 25 years ago there was massive resistance from the building industry, which I think is almost as conservative now as it was then. Also poor construction often defeats good design. I would like to see compulsory thermography and pressure testing for leaks of all new houses, but I doubt it will happen.

A Scottish equivalent of Passivhaus would probably include better protection against damp penetration, eg a wider wall cavity, this is needed because rain is often more horizontal in Scotland than in Scandinavia. One of the objections to my Building Regs proposals was that thicker walls would reduce the number of houses that could fit onto a plot!

In reply to kevin stephens:

I don't think it will until we a consistently oversupplying wind power.

This is likely to happen by the end of the decade (maybe 2035).

At this time focus will turn from production to storage.

I walkways thought Pumped Hydro Power would be the obvious cost effective way forward but I was just reading about Coire Glas that's due to double our storage by adding 30GWH at a cost of £1B.

That's £30,000 per KWH. Why pay so much per KWH? that's huge when batteries are a fraction of this.

If the UK where to have 3 days of storage we would need a total of 2.5 Billion GWH. At £30,000 per KWH this is a cost of 80 quadrillion.

That's 27,000 times our Annual GDP.

Problems.

In reply to kevin stephens:

It's ridiculous that brick-faced houses are still allowed - shrinkage means the cement always comes away from one side of the vertical joints making them susceptible to wind-blown damp penetration, plus the bricks are big sponges themselves.  Wet & windy weather simply turns brick-faced houses into giant evaporation fridges!  I'm not sure that airtight houses are appropriate for the UK either - our humid, maritime environment means mould grows far better than it does on the drier continent.

Developers will always build as profitably as possible. They have no interest in the environment if it reduces their profitability. That's why they're fitting gas boilers and not heat pumps - far more profitable to them and normally makes their houses easier to sell because they're cheaper.

In reply to Toerag:

Hopefully recent heating costs may change that a bit. Our house is a 1920s semi, brick (no cavity), suspended floor and I fully expect it to lose a lot of value compared to a modern property. Terraced houses obviously better re heat loss; perhaps detached properties will start losing their appeal.

Neighbour's daughter delighted with her recently built flat....she said she hasn't needed to turn heating on (that was a couple of weeks back) but its hard getting used to the silence as internal and external soundproofing so good. Maintenance costs frightening though.

In reply to Toerag:

The aim of pressure testing is not for an airtight house, indeed minimum controlled ventilation is required under the regs. Pressure testing with controlled vents closed is to find the gaps around windows etc due to hidden bodges in construction, in much the same way that thermography can find cold bridging defects 

In reply to montyjohn:

I may have made an error myself given the ease with which large powers of ten can get muddled. However I think your calculations are a bit out.

if it were to cost £30 thousand per kWh that would be £30 million per MWh, or £30 billion per GWh. Which would be £900 billion for 30 GWh, and it’s actually only (!) costing  £1 billion apparently.

so it would be a mere 30 times annual GDP to store 3 days worth for the UK. 
 

It doesn’t make any difference to the issue that UK geography has nowhere near enough locations where pumped storage is a possibility though.

In reply to rinnes:

Indeed. The purpose of pump storage is for everyone brewing up in the ad' break during a particularly traumatic episode of Coronation Street or World Cup quarter final.  Pump storage is not feasible for storing a number of days wind turbine output

In reply to rinnes:

I think you may be right.

What I was doing was testing all of you to see who was paying attention.

ok so it's one million KWH to a GWH (I calculated it based on one thousand).

Which gives you £33 per KWh (or £30, I like round numbers).

Much more palatable.

It's spare change now.

I hadn't got this far when my calculations showed a god awful amount of cost. It still is God Awful.  I assume places like Coire Glas are the low hanging fruit so it will only get harder and harder to find more locations.

In reply to montyjohn:

Maybe try 1500MW i.e generating capacity for an estimated 50 years

Hickley C is 3260MW is estimated at £26Billion lololol for an estimated 60 years

not such a bad deal

In reply to artif:

Not sure i follow.

You're comparing energy production with storage which I don't think is valid.

It only generate 1500MW if you fill it up with an excess of 30GWH of grid energy.

At least with Hinkley C you can fill it with some of those cute little glowing rod things and get 3260MW all day long. 

The interesting comparison however, is comparing the numbers to wind.

Offshore wind is about £2.4M/MW, so to match Hinckley C would be a CAPEX of less than £8Billion.

Still not comparing like for like since nuclear gives a reliable base generation.

So let's add four Coire Glas pumped reservoirs to our £8Billion offshore Wind farm, so it now costs £12Billion.

That should be enough storage for 3 days, output should be similar to Hinckley and it's less than half the price, and it's green.

Well, blue actually, as it floods the nice walks and paths and habitats and turns them into temporary lakes.

In reply to montyjohn:

I wasn't classing hydro as storage but it seems I was wrong (not unusual).

I still think you costs are out, as you seem to pricing the 30GWH as a one off. i.e there's potential to produce 30GWH regularly, not daily but certainly more than weekly 

Maybe mixing GW with GWH confuses the issue

In reply to montyjohn:

But windmills don't last very long.

In reply to jimtitt:

On the offchance that isn’t a wind up; How long does a wind turbine last compared to the core of a gas turbine or steam turbine?

In reply to jimtitt:

Don't worry, they only need to last as it takes for Fusion to be available. 30 years last time I checked.

Although, check out what Helion are doing. Very exciting stuff. 

In reply to kevin stephens:

Since we're talking about offshore wind is this a pun?

In reply to kevin stephens:

The ones being dismantled in the N Sea are 20 years old, that's how long they have certification for. The whole generating unit isn't exactly serviceable, once the bearings go they are finished.

In reply to jimtitt: are the masts retained, also the cables and other infrastructure?

In reply to kevin stephens:

No, because technology has moved on. A 20yr old turbine will be 1-2MW.  A modern offshore one will be 8-15MW, with better-designed blades and dynamo. It'll reach faster, more consistent wind higher up. Existing masts aren't big enough, existing foundations not strong enough, and existing cables unlikely to be capable of carrying the higher power outputs.

In reply to kevin stephens:

The guidelines say leave nothing but now some of the underwater construction ( the foundations and the anti-scour thingies) are colonised as reefs so they might become protected instead. The towers go.

In reply to Toerag: so as the technology and engineering matures 8-15 MW will become standard and the existing masts and cables etc can be retained when the turbines and dynamos are replaced?

In reply to kevin stephens:

Or they will be superceded by larger floating systems, it's anyones guess.

In reply to jimtitt:

Indeed

In reply to kevin stephens:

'Cold fusion.' Whatever happened to that?

In reply to kevin stephens:

Cables, transformers etc will all have to be uprated, bigger hammers to drive the piles as well. As mentioned, floaters for deep water will open a lot of new areas.

In reply to kevin stephens:

The solution for multi-day still, dull, winter lulls will be largely 'conventional': CCGT on standby (probably where we'll start out early-mid century) or very flexible (mostly underused) nuclear (where I'd guess, in the absence of radical new tech we'll probably end up late century). Maintaining significant standby capacity will just be the price of a clean grid until it's undercut by a large scale storage solution which is still mostly an idle asset adding cost in exchange for resilience.

The ability to cold start the system after a significant/total collapse also needs to be borne in mind, unless the myriad distributed renewables can be brought under centralised control (coupled with equally good and granular remote control of load) that does imply the need for some really beefy stand alone power sources or very good granular control of load.

That said, as we bring more and more loads onto the grid that have very flexible duty cycles like EVs and thermal stores then there is when coupled with good forecasting and some degree of remote control (direct and or through market forces), much scope for virtual storage: pre-loading distributed stores (including the thermal mass of buildings, cold stores etc) while supplies are more readily available in the run up to forecast lulls and shedding load when supply is scarce. That alone won't carry us through long winter lulls but it will make the supply demand mismatch much less pronounced during shorter lulls and it will change what we consider 'long' meaning less gas burned and less expensive grid-scale storage to carry us through.

jk

In reply to jkarran:

Isn't hydrogen the ideal technology to pair with renewables to take us through till the physicists and engineers get fusion working and scaled?

As a complete layman, using excess wind to generate hydrogen from seawater on offshore farms in the North sea, to be stored in deleted gas fields and pumped back to the mainland for power generation, seems like as green a solution as we're going to find, and doesn't sound like it would need any significant breakthroughs now, just the will to do it?

In reply to kevin stephens:

Masts are cyclically loaded each time a blade passes them. Obviously they're sized to survive the maximum wind-load++ but whether that over-sizes them sufficiently that their fatigue life exceeds two lots of generating equipment, or indeed whether the mast sizing is actually driven by fatigue for one system lifespan I don't have a gut feeling either way.

Either way, steel is highly recyclable. The composite blades, less so! I think they still mostly get shredded and burned for energy.

Interestingly the aerofoils have evolved to become more damage tolerant maintaining good efficiency into later life. Weather damage (leading edge wear and chips) and contamination (bugs, water and ice) is inevitable. Mirroring a trend in aviation, some earlier designs were highly optimised for performance when new but degraded badly under real world conditions whereas real world performance actually comes from operating well under a range of conditions.

jk

In reply to Ciro:

Conversion of surplus electricity into hydrogen then from hydrogen back to usable energy is very inefficient so a lot of the surplus wind energy would be wasted.  The infrastructure to store and distribute hydrogen would be very expensive; other than mixing 20% volume; 6% energy content with natural gas which hardly makes it worthwhile

CCGT has a future in enabling wind power to be practicable and cost effective, albeit with a lot less contribution than at present

In reply to Ciro:

I remain to be convinced by hydrogen*, it's nasty to handle and the end to end efficiency of electricity-hydrogen-electricity at the moment is just horrible. In its favour, we can potentially store a lot of it seasonally in depleted wells gradually building up a strategic reserve and also for more immediate use in slightly more transportable forms like ammonia. In theory at least we can just burn H2 in lightly adapted existing tech which is appealing. I think the reality is that adaptation won't be particularly light and the ongoing poor conversion efficiency will leave it at a price disadvantage outside of certain applications (steel and maybe, probably not, aviation).

*and fusion for that matter!

Long run we certainly need some sort of efficient electrical-chemical energy conversion process unless there's a massive breakthrough in battery technology.

jk

In reply to jkarran:

Correct, they often get burnt in cement kilns as fuel. However, they can be used to make things like bike shelters, or ground up to make building aggregate.  New blades are, however, completely recyclable, the resins can be decomposed to allow long fibre recovery.  The anti-wind lobby like to complain that blades in the USA often get landfilled, but landfilling fibreglass is pretty harmless.

In reply to compost:

I realized I didn't know how much it cost to switch my average gas combi boiler on.  Seems about £3 hour on full.

In reply to David Riley:

I don't know if that's good or bad, but how hot do you have the output temps set to?  It's significantly more efficent running in the 'condensing' range (<55-60C). Check out the orange/black graph at the bottom of this page, then go back and read the whole thing.  I was aware that lower output temps were good, but I hadn't realised the effect of reducing the flow to lower the central heating return temps too.

https://www.heatgeek.com/condensing-boilers-efficiency/

In reply to Brown:

I looked at some last week, the results are quite variable.  It would be prudent to try a few, select the highest BTU requirement and take that as a minimum - over-sized radiators aren't a problem unless there's a lack of finance / wall space but they have tremendous benefits - faster heat up, lower flow temperature requirement (better efficiency for condenser boiler) & lower flow requirement (lower return temp for better condenser efficiency). Plus they make going to heat pump more viable.

In reply to Toerag:

When a boiler is turned on it will be at maximum to heat up.  Taking this as 25KW at 11p each = £2.75 plus flue losses.

In reply to David Riley:

Unless there is something very weird going on, maintaining a flow temperature of e.g. 55C for an hour will obviously require less energy than maintaining a flow temperature of 70C for an hour.

There's also ample observational evidence available that boilers aren't working at maximum when set to a lower flow temperature; the noise of my boiler is almost unnoticeable when set at 3 or below, and quite intrusively loud at 6. Definitely not working at maximum power on lower settings.

In reply to Stuart Williams:

Not necessarily. It depends on the difference between the flow temperature and return temperature, also the flow rate if that varies, eg by operation of thermostatic radiator valves, depending on the pump curve  

In reply to compost:

Having looked into this I'd say that a heat pump will cost a similar amount to run as a gas boiler but will cost more than £10k up front vs £3k for a new boiler.

What maybe a better option is a new gas boiler and add some air to air heat pumps (aka air-con) units for heating/cooling your favourite rooms. Then add solar power.

In reply to Toerag:

The maths is quite simple and if you know the size of your building, the u-values of your walls, floor, roof, windows, and doors you can do it in excell.

It's a basic steady state heat loss calculation that looks at conductive losses, infiltration, ventilation, and an extra bit of heat loss for non-repeating thermal bridges. You need to know your locations "minimum" temperature and what temperature you want your rooms.

Then multiply everything by twenty percent to ensure its big enough to get a timely warm up. I'd work in SI units to make things simple.

If you have access to such things it's all detailed in CIBSE Guide A which is basically a Bible of designing HVAC.

Estimating u-values is its own challenge in old buildings.

In reply to kevin stephens:

I've no doubt you are more knowledgable about this than me, but even just from the audible evidence and from my energy bills it's clear to me that my boiler doesn't operate at maximum power regardless of the flow temperature settings.

I just can't see how running my boiler on it's highest setting for one hour would use the same amount of energy as running it on it's lowest setting for the same amount of time.

In reply to Stuart Williams:

Same as you.

My 8 yr old combi certainly does not use max output for heating normally except for the first few seconds of firing up. Only in very exceptional circumstances of temp and demand will it use near to max for short periods but even then it is more likely to be up to 75% only. I’ve only seen it using max or near max for a very large draw of hot water.

Most of the time mine runs at only about 20% its output (according to it’s own display) when it is actually on with heating demand. I’ve checked my last bill (Nov) and my average daily gas use in kw for all hot water and heating is just under what the boiler could theoretically use in an hour if running at max stated output.

In reply to David Riley:

You are needing a new modulating gas boiler if your boiler is running at its max output. 😉

My combi programming controls its output, for heating, for economy at all times and not heat output. My boiler will certainly not run at max output (for heating) in the first hour no matter what setting I could use. 

In reply to Climbing Pieman:

In the cold weather I've found I need to run my boiler at max at least for the first few hours of the day. Our most important rads are old heavy ones and I'm pretty sure that modern thin walled , finned rads will solve the problem.

In reply to compost:

A modernish combi shouldn't run full bore when heating, but reserve that for times of heavy DHW (hot water) demand .

Gas Combi are very cheap compared to other options. For a small medium house you should be able to get a budget Ideal boiler for about £1k and then to change the existing about £500-£700 labour including a power flush, with the £500 for an easy swapsie and more if there are any complications.

A new combi should be more efficient than current one.

In reply to Toerag:

It's not so straightforward, if your radiators are large enough or even over sized the running low temps is good, if the radiators are essentially too small eg. due to a crap diy effort by your landlord, running low flow temperatures just means you have a cold house and can end up using more electric because you have the boiler running continuously. Most modern boilers don't give you any control of the flow rate.

In reply to gethin_allen:

Obviously one has to increase water temperature if the flow can't be altered. Is it still often possible to increase pump speed but this is rarely done except by a professional partly because the pump is hard to access, or are the pumps indeed single speed?

In reply to Brown:

If anyone’s interested I have good condition CIBSE Guides A, B and C available for sale, or swap for a copy (not web copy ) of Extreme Rock

In reply to oldie:

On my boiler the pump was multi speed but controlled by the computer.