We are currently renovating a property and are in the position of having the choice of either a mains gas or kerosene boiler. Mains gas is obviously much more convenient but is there a way of comparing the cost of the different fuels? I have seen various figures for the energy content of kerosene in kilowatt hours but are gas boilers more efficient than oil boilers?
Depending on your location as well as accounting for the install costs of various systems, have you looked at a heat pump, solar and batteries, if you did that a lot of your energy usage for most of the year would be free going forward and during the winter you could draw power on cheap night rates and use that to run the heat pump as required, if you are doing a lot of work on the property depending on external works a ground source heat pump would be the best option as you will get a higher COP and so more energy output for input.
As far as I can gather from the Grant oil boiler technical website, for their boilers that will work with HVO, switching involves the need for a new nozzle and adjustments to the high pressure oil pump setting.
So not a lot different to an annual service.
I suspect it will be a case of running the tank as low as possible on kero, then filling completely with HVO to minimise the mix.
ISTR that Mitchell & Webber were suggesting draining the tank, when they were running the trials. They may just have been playing safe though.
Useless George Eustice's '10 minute Rule Bill' on this topic, passed its first reading today. The linked web site, worryingly, repeats the claim I've seen before:-
Under current Government proposals, all “off-gas grid” homes in rural communities will be banned from purchasing replacement boilers from 2026 and expected to have an air source or ground source heat pump system instead.
Depending on your location as well as accounting for the install costs of various systems, have you looked at a heat pump, solar and batteries.
The solar part clearly has very little bearing on Winter heating, so this is really a 're-imagining' of Night Storage Heaters. But whereas a single NSH can store 24KW.h, an equivalent battery would cost an arm, a leg and your first-born child!.
I used 206 litres of Oil in December, so 206 / 31 * 10.35 = 69KW.h per day.
A Heat Pump should require 1/3 x 69 = 23KW.h per day.
If all the electricity was at the current cap rate of 34p/unit, then a Heat Pump would normally cost 23x0.34 = £7.82 per day (for my house). (The oil cost £5.80 per day. Gas if it was available would have been £7.42)
You could argue that the power used overnight - assuming the Heat Pump is still running - doesn't need to be stored. That would reduce the storage requirement by 7/24ths (assuming Economy 7).
That would give a required battery capacity of about 16KW.hr
Still bigger than a single Tesla Power Wall 2, so you couldn't store it all. (They come in £10K increments, so a 2nd one probably wouldn't make sense).
Ignoring the effect on 'normal' electricity usage, switching to E7 @ 46.72/14.90p per unit (E.ON) and assuming a Powerwall 2 @ 13.5KW.h, would give a daily cost of
(13.5 x 0.149) + (6.7 x 0.149 ) + (2.8 x 0.4672) = £2.01 + £1 + £1.31 > £4.32 per day.
(13.5KWh at night rate to battery, 6.7KW.h at night rate to Heat Pump and 2.8KW.hr at day rate to Heat Pump).
A daily saving of £7.82 - £4.32 = £3.50 would pay for the Powerwall 2 in about 9 years...
The tariffs aimed at EV owners might work out better - but my supplier (E.On) doesn't seem to have one yet. (Are they reserved for actual EVs ... or are batteries counted as equivalent. Do battery systems have timers for charging overnight, or are they all geared around saving excess solar?)
This is admittedly very simplistic and ignores pay-back to the grid in summer and the maximum charge + discharge rates of the Powerwall 2. (Equally, the calculations assume the same heating usage in Summer - which clearly wouldn't be true)
As far as I can gather from the Grant oil boiler technical website, for their boilers that will work with HVO, switching involves the need for a new nozzle and adjustments to the high pressure oil pump setting.
So not a lot different to an annual service.
I suspect it will be a case of running the tank as low as possible on kero, then filling completely with HVO to minimise the mix.
ISTR that Mitchell & Webber were suggesting draining the tank, when they were running the trials. They may just have been playing safe though.
I happened upon something in the Riello RDB Burner manual on this topic (as used by Grant):-
Particular attention should be given to the oil storage tank and supply to the burner. Riello recommends that existing oil storage tanks are cleaned, inspected and any traces of water are removed BEFORE bio fuel is introduced (Contact the tank manufacturer or oil supplier for further advice). If these recommendations are not respected this will increase the risk of contamination and possible equipment failure.
It is strongly recommended that with Bio fuel use, oil filters are inspected and replaced every 4 months. More regularly where contamination is experienced.
There were other things too, such as checking that everything in the supply lines is Bio-compatible - and that the fuel "meets the relevant standard".
Riello reduce or remove their warranty on certain components, if the bio content > 30%...
Phil, that is interesting, but I wonder if we are getting into confusing territory on fuel nomenclature. Riello may be using the term bio fuel to mean "traditional" first-generation biodiesel, which is an entirely different beastie to HVO. My understanding is that Biodiesel is much more prone to problems of water absorption and microbial growth than HVO, which is why the specification is normally at 7% maximum for biodiesel, while HVO can be used at 100%.
That may well be the case - there's no mention of "HVO" in the Riello manual, just fuels conforming to EN 14214. A google search for "HVO" says it conforms to EN 15940 - but links for that says it's a drop-in replacement for diesel, not kerosene!
I am definitely confused.
Is it some new variant of HVO is involved, which is not yet commercially available and doesn't have an "EN" number?
Yes, the standards seem to be a real nightmare to make sense of. In practical terms, I have always understood kerosene and diesel to be almost completely interchangeable, with the exception of lubricating ability (and taxation!).
Since I already put an additive into my CH Kerosene to improve the lubrication on the fuel pump and have once (in extremis) resorted to using diesel in place of kerosene, I'm pretty sure that I could use HVO in my Rayburn with minimum changes. Since the viscocity is slightly different, then for efficient combustion it makes sense that for longer term use, the fuel pressure might need to be corrected and the nozzle(s) changed to ensure the correct spray pattern, but these are easy routine service tasks.
Yes, the standards seem to be a real nightmare to make sense of. In practical terms, I have always understood kerosene and diesel to be almost completely interchangeable, with the exception of lubricating ability (and taxation!). .
I don't think that's the case, normal heating oil is described as "28 seconds" whereas Diesel is "35 seconds" which is a significant difference. Some appliances may be happy with either, for example the Eberspacher heaters and their clones. Some definitely are not, as we found trying Red Diesel in an Esse cooker once.
Yes, the standards seem to be a real nightmare to make sense of. In practical terms, I have always understood kerosene and diesel to be almost completely interchangeable, with the exception of lubricating ability (and taxation!). .
I don't think that's the case, normal heating oil is described as "28 seconds" whereas Diesel is "35 seconds" which is a significant difference. Some appliances may be happy with either, for example the Eberspacher heaters and their clones. Some definitely are not, as we found trying Red Diesel in an Esse cooker once.
That's interesting, which Esse? I used to use diesel and kerosene interchangeably in an old Esse - I'm not sure which model it was but it had a very simple burner, where the oil basically dripped down a tube, spread across the base of the burner-chamber and burned. Occasionally the end of the tube would get blocked with the clinker that built up on the base of the chamber, but I can't recall it being markedly worse with one fuel rather than the other.
I couldn't tell you the model I'm afraid but the burner sounds the same, oil flowed into the bottom and combustion air entered through the perforated sides. Running on Diesel it all sooted up, burner, boiler oven etc. It was one hell of a job cleaning it out.
I wonder, and this would be the wildest uneducated guess, but I wonder if appliances designed for Diesel are happier with kerosene than vice-versa. Maybe your Esse was setup for Diesel, it wasn't that uncommon given that Red was around the same price as heating oil. Rayburns had "K" or D" model versions.
Replies
Useless George Eustice's '10 minute Rule Bill' on this topic, passed its first reading today. The linked web site, worryingly, repeats the claim I've seen before:-
I used 206 litres of Oil in December, so 206 / 31 * 10.35 = 69KW.h per day.
A Heat Pump should require 1/3 x 69 = 23KW.h per day.
If all the electricity was at the current cap rate of 34p/unit, then a Heat Pump would normally cost 23x0.34 = £7.82 per day (for my house). (The oil cost £5.80 per day. Gas if it was available would have been £7.42)
You could argue that the power used overnight - assuming the Heat Pump is still running - doesn't need to be stored. That would reduce the storage requirement by 7/24ths (assuming Economy 7).
That would give a required battery capacity of about 16KW.hr
Still bigger than a single Tesla Power Wall 2, so you couldn't store it all. (They come in £10K increments, so a 2nd one probably wouldn't make sense).
Ignoring the effect on 'normal' electricity usage, switching to E7 @ 46.72/14.90p per unit (E.ON) and assuming a Powerwall 2 @ 13.5KW.h, would give a daily cost of
(13.5 x 0.149) + (6.7 x 0.149 ) + (2.8 x 0.4672) = £2.01 + £1 + £1.31 > £4.32 per day.
(13.5KWh at night rate to battery, 6.7KW.h at night rate to Heat Pump and 2.8KW.hr at day rate to Heat Pump).
A daily saving of £7.82 - £4.32 = £3.50 would pay for the Powerwall 2 in about 9 years...
The tariffs aimed at EV owners might work out better - but my supplier (E.On) doesn't seem to have one yet. (Are they reserved for actual EVs ... or are batteries counted as equivalent. Do battery systems have timers for charging overnight, or are they all geared around saving excess solar?)
This is admittedly very simplistic and ignores pay-back to the grid in summer and the maximum charge + discharge rates of the Powerwall 2.
(Equally, the calculations assume the same heating usage in Summer - which clearly wouldn't be true)
Some links I found:-
Battery storage in general
Tesla Powerwall
It is strongly recommended that with Bio fuel use, oil filters are inspected and replaced every 4 months. More regularly where contamination is experienced.
Riello reduce or remove their warranty on certain components, if the bio content > 30%...
I am definitely confused.
Is it some new variant of HVO is involved, which is not yet commercially available and doesn't have an "EN" number?
This seems to be the best info. I can find - but it's far from definitive: https://futurereadyfuel.info/
Since I already put an additive into my CH Kerosene to improve the lubrication on the fuel pump and have once (in extremis) resorted to using diesel in place of kerosene, I'm pretty sure that I could use HVO in my Rayburn with minimum changes. Since the viscocity is slightly different, then for efficient combustion it makes sense that for longer term use, the fuel pressure might need to be corrected and the nozzle(s) changed to ensure the correct spray pattern, but these are easy routine service tasks.
I wonder, and this would be the wildest uneducated guess, but I wonder if appliances designed for Diesel are happier with kerosene than vice-versa. Maybe your Esse was setup for Diesel, it wasn't that uncommon given that Red was around the same price as heating oil. Rayburns had "K" or D" model versions.