The Lemon Fool

I've attached a graph of our 2021 energy use to date in kWh, courtesy of Scottish Power reporting.

A couple of observations.

1 You can see that our total monthly energy usage varies between 3,500 kWh in January to 500 kWh in June. Our house is fairly well insulated, has new windows and our gas central heating has 4 heating zones. I cannot visualise that our house could be heated to the same degree of comfort by consuming LESS energy if going fully electric, particularly in a NE Scotland winter.

2 You will see an increase in electricity use in August. This is due to the installation of a Charger for our BEV. I think this has probably been a good decision.

Why is there an increase in gas usage June to August ?

Family up from London in August for 3 weeks......hot water used.

Never mind a house, can the whole grid cope?

I know the experts say yes it can, but I do get the feeling they are just toeing the company line. A bod on the radio from the gas network the other day dropped the pretence by pointing out the gas network transmits four times the energy of the National Grid, so no amount of load balancing (i.e. charging cars at night) is gonna deliver the amount of electrical energy that private houses currently use as a mix of gas and leccy together.

* My daily standing charge is 42p for gas & electric so that totals £153.30 a year.....more than paid for by the Gov' winter fuel allowance.
* Solar panels provide free hot water most of the year and electricity charges are minimal as solar power provides most of it.
* A wood burner keeps us warm part of the year.
* Low cost portable gas heaters supplement the gas central heating.
I'm keen to replace the boiler with an air sourced heat pump soon.

Not convinced by the 4* figure (if not only because of the double counting, as half the gas is used to make electricity at 60% efficiency)

https://assets.publishing.service.gov.u ... otice_.pdf has lots of numbers, including

Natural gas demand 878 TWh (including power stations)

total supply of electricity in the UK 346 TWh

Which suggests that if we had only gas power stations we'd need the complete gas supply to run the electricity grid.

https://en.wikipedia.org/wiki/Energy_in ... atural_gas says

Gas was almost 40% of total primary energy supply (TPES) and electricity more than 45% in 2010

which leaves 15% for transport etc.

So a decarbonised National Grid might need to transmit double the power currently. But with average demand 35GW and peak 52GW, a more load-balanced grid would not need to grow as much.

My house runs entirely on electricity, E7 tariff. The difference is that it is a new build with huge amounts of insulation. I'm just coming up to my first year in the place so haven't got all the usage figures together as yet. My guess is that total electricity cost for the year has been around £1000. This is for a large 5 bed detached house with three occupants. Once I've got the first years figures together I will be able to tell what the payback period for solar PV and heat/or heat pumps is likely to be.

I have a 1960's bungalow.

We use about 15000 kWh per year of gas for heating and hot water, and 3000kWh of electricity for running everything else in the house. I also have an electric car, and solar panels that generate about 4000kWh per year.

The electricity side is great - I generate all I use in the house, and quite a bit of what I use in the car. (All, in the sense that I can export and re-import power at different times). I also have a cheap overnight tariff for car charging which soaks up that spare overnight power from the grid.

I see no easy solution for heating and hot water. A heat pump would require some major surgery to the house, to improve the insulation and revamp the central heating system. I have no more roof space for additional PV or hot water solar.

I don't know what I will do when the time comes to replace the gas boiler. I guess I am waiting to see what government policy is to be on upgrading older houses like mine. They are going to have to do something if they are serious about tackling climate change.

FD

I'm going to wait until there is an affordable alternative, new technologies to a gas boiler.

I'm kind of sceptical about this enforced green agenda, whilst boris flies round in a vip airbus 330 and celebrities and royals lecture us on climate change whilst having massive carbon footprints themselves.

Solar PV can be configured to provide domestic hot water but you do need a hot water tank and an immersion heater.

Mike4 wrote:Never mind a house, can the whole grid cope?

I know the experts say yes it can, but I do get the feeling they are just toeing the company line. A bod on the radio from the gas network the other day dropped the pretence by pointing out the gas network transmits four times the energy of the National Grid, so no amount of load balancing (i.e. charging cars at night) is gonna deliver the amount of electrical energy that private houses currently use as a mix of gas and leccy together.

Thats a bit of a bugbear of mine: Ask National Grid and they say yes there's plenty of capacity in the grid. That's because there is in the 132kV+ transmission grid they operate. Ask the regional electrical companies who operate the 33kV distribution grids fed by NG and you'll get a very different answer.

The biggest challenge isn't going to be generating or even transmitting enough leccy, it's all the hundreds of thousands of cables and substations in every neighbourhood that can't cope with the demand already

Surprised I’m the one defending renewables. But those raw numbers don’t tell the whole story..

Gas boilers convert gas to heat at up to 90% efficiency.
Heat pumps convert electricity to heat at somewhere around 300% efficiency**. Because the heat doesn’t come from the leccy, it comes from the air.
So for domestic heating you don’t need nearly as much electricity supply as gas supply**.

Gryff

** Yes. Right up until the air temperature falls well below freezing, at which point ASH is useless, and everyone reverts to convection heating and we have a REAL grid problem.

Thanks to everyone for contributing such interesting comments so far.

The chart at the beginning of the post was based on energy kWh. In order to get my head around the equivalent in cost (maybe more pertinent to a lot of folks) I have produced the attached chart of actual 2021 cost and an equivalent cost for whole home energy based on all electric.

This is an honest attempt at a comparison and the following assumptions have been made :

1 Assumes an equivalent degree of comfort and heating latency will be achieved (probably need 2 heat pumps)
2 Assumes a 20% reduction in overall energy use by the application of innovative technology (maybe optimistic) Todays energy tariffs used.
3 Cost comparison does not include amortised capital cost of retro-fit insulation and novel heating hardware installation or PV.
4 Does not allow for supplementary heating from wood burners or bottled gas, assumed will be banned.

That's a lot of power the OP is using. I live in a 2bed house in NE Scotland run on electricity plus a wood burner for heat and water. I use between 1300 and 2200kwh per YEAR of electricity, less than the OP uses a month for most months.

gryffron wrote:Surprised I’m the one defending renewables. But those raw numbers don’t tell the whole story..

Gas boilers convert gas to heat at up to 90% efficiency.
Heat pumps convert electricity to heat at somewhere around 300% efficiency**. Because the heat doesn’t come from the leccy, it comes from the air.
So for domestic heating you don’t need nearly as much electricity supply as gas supply**.

Gryff

** Yes. Right up until the air temperature falls well below freezing, at which point ASH is useless, and everyone reverts to convection heating and we have a REAL grid problem.

Good point. With an efficiency difference of about x3 and a price difference of about x3 then the heat pump and gas boiler should cost about the same to heat a home.

As regards the performance of the heat pump in cold weather, this is why I would favour a ground source heat pump, because the ground temperature is more stable than the air temperature through the year, particularly if the bore hole is vertical rather then horizontal. If only it didn’t cost so damn much!

FD

PhaseThree wrote:My house runs entirely on electricity, E7 tariff. The difference is that it is a new build with huge amounts of insulation. I'm just coming up to my first year in the place so haven't got all the usage figures together as yet. My guess is that total electricity cost for the year has been around £1000. This is for a large 5 bed detached house with three occupants. Once I've got the first years figures together I will be able to tell what the payback period for solar PV and heat/or heat pumps is likely to be.

I live in a similar house but built in the last century in Southern UK. Its had extra loft insulation and cavity wall insulation retro fitted. With gas central heating. Our total energy costs have averaged around £1,500 a year (last year £1,200 thanks to a now defunct supplier!). So, in current conditions, payback on changing the system to all electric would be likely to be many many years (if ever!).

Obviously when the time comes to replace the boiler the decision may be made for us if there are major government grants/penalties applied.

We did install aircon to two rooms a few years ago and the air-sourced heat pump costs very little to run and is used for single room heating in Spring and Autumn. It won't pay back its cost in savings but does improve comfort.

regards

Howard

As my gas boiler was over 20 years old. I decided to move to all electric, starting 1st November 20. I am unable to tell you what the years cost has been as the supplier has screwed up my account and ignored all the readings up to the point they fitted a Smart Meter. This has shown that my usage during the summer months has been very small. I had been getting a very good starting rate so I expected that I would have to move on at least 3 weeks before my year end. It takes this for a transfer to take place. In September they offered me the new deal, a fair old increase in KWH and Standing Charge. I did a search and to my surprise their offer was the best. This was at the time of all the chat about big increases, anyway I signed up for 2 years. I find I have more control with electric. I leave the radiators at preset levels and if it gets colder they will fire up set at 14/15c I heat up the rooms that I am actually using. The modernwater heater £300 to buy is on 24/7 at 55c but hitting the required 65c now and again. Over the last year I have carried out some research on this energy problem. This is my view.

Air Sourced Heat Pumps. Very good under special conditions, especially underfloor heating and great insulation. No mention ever made about annual Servicing cost. The Grants a total disgrace having the poor subsidising the rich and you have to be rich to fit these.

I have invested in what I think will actually happen. Gas boilers running on 20% Hydrogen and natural gas with an unbelievable promise to go 100% in due course to keep the Greens happy. This is the only way to utilise the massive pipe grid that exists. It will also soak up all available renewable electricity to make the Hydrogen. The back up generators will also be able to run on pure Hydrogen or a mix. So I think I am on a winner only time will tell. The gas boilers will only cost a little more than current prices and some will be suitable for conversion.

The claim that the modern gas boilers are 90% efficient is possible but unlikely as people use time clocks,. This means long periods at full bore to catch up. To be very efficient they are supposed to just trundle along maintaining a basic heat and can handle the higher comfort levels where you need them
your thermal store is always ignored. Insulated walls furniture carpets etc. The manufacturers actually suggest you leave the heating on and buy a special sensor placed outside and it controls the heating system. The ASHP works on a constant low temp if you have underfloor heating. A time clock screws this up.

taken2often wrote:Gas boilers running on 20% Hydrogen and natural gas with an unbelievable promise to go 100% in due course to keep the Greens happy. This is the only way to utilise the massive pipe grid that exists. It will also soak up all available renewable electricity to make the Hydrogen. The back up generators will also be able to run on pure Hydrogen or a mix.

The basic problem with making hydrogen from electricity is that you lose half the original energy in the process of making and distributing it, compared to losing 5-10% in electricity distribution. So it's always going to have higher running costs than even direct heating with electricity, never mind with the multiplier effect of heat pumps.

The other problem is that there are going to be so many other applications that will be ahead of heating in the queue for hydrogen. For the next decade or so, all the hydrogen that can be produced will be going into chemical plants, fertiliser plants and the like. There will be a niche for hydrogen in domestic heating, but I suspect it won't be more than 10-20%.

Obviously the big attraction is that upfront costs to consumers are potentially much lower, but I think you'll see deals for heatpumps more akin to the iPhone model, where the upfront cost gets amortised over the course of a contract, perhaps with other providers able to take over mid-contract. Or the long-mooted "heating as a service" type contracts.

We'll get a clearer idea by 2026 according to the recent Hydrogen Strategy - the current plan is to have a 300-home trial in Fife in 2023, a "village-size" experiment by 2025, and then a big decision in 2026 on the future of hydrogen in heating, there may be a town-size trial by 2030 - "we expect overall the demand for low carbon hydrogen for heating by 2030 to be relatively low (<1TWh)". They're suggesting that by 2030 the dedicated hydrogen pipeline system will only be a few 10's of kilometres, with the potential for national distribution by 2050. pp76-78 talk about the prospects for blending with a decision in late 2023 on whether to start blending with a target of 20% - it seems they're quite keen on the idea just to encourage investment by providing producers with an offtake-of-last-resort, even if the benefits otherwise are pretty marginal.

"We aim to consult (later in 2021) on the case for enabling, or requiring, new natural gas boilers to be easily convertible to use hydrogen (‘hydrogen-ready’) by 2026"

But I think most (***not all***) will end up electric.

.

re Air Sourced Heat Pumps.

has any one noticed the amount of NOISE from the fans .

if these are adopted in urban areas , i suspect their noise will swamp road traffic noise .

jackdaww wrote:.

re Air Sourced Heat Pumps.

has any one noticed the amount of NOISE from the fans .

if these are adopted in urban areas , i suspect their noise will swamp road traffic noise .

Do you have any evidence for this? I have a modern air sourced heat pump and it's incredibly quiet. Even standing outside listening late at night it's barely audible. Much quieter than the rustle of leaves on trees in our country environment. The same is true for neighbours' units.

regards

Howard