Navitron Renewable Energy and Sustainability Forum

General Renewable Topics => General Discussion => Topic started by: Eccentric Dyslexic on February 13, 2018, 06:54:33 AM



Title: Is this correct?
Post by: Eccentric Dyslexic on February 13, 2018, 06:54:33 AM
Can someone more maths oriented confirm if the info I just found posted on a Facebook group is correct please?

“Its a guide to heating energy costs (prices change but its but not far off)

2.9t wood chip = 10,000 KWh = €370.00
2.6t logs = 10,000 KWh = €430.00
2.1t Pellets (pumped) = 10,000 KWh = €660.00
56g (1KWh) Heat pump = 10,000 KWh = €700.00
2.1t Pellets (bags) = 10,000 KWh = €720.00
1000ltr oil = 10,000 KWh = €850.00
180g(1KWh) Electric = 10,000 KWh = €1550.00
257g (1KWh)  LPG = 10,000 KWh = €1640.00”

Cheers

Steve


Title: Re: Is this correct?
Post by: Countrypaul on February 13, 2018, 07:39:47 AM
Using the figues in that table, the heat pump only has a performance factor of slightly over 2 (assuming the electric is the same price for the HP and direct) which sounds rather low but without more context difficult to be more specific on. The electric for both appears to be a standard tariff rather then an E7 one that might be used for heating so probably over double what might be charged for an E7 price.

The energy output for oil seems about right at 10KWh/L - the cost is faily volatile, but a quick check on BoilerJuice seems it is around 50p/L so around €600.00.


Title: Re: Is this correct?
Post by: M on February 13, 2018, 07:50:41 AM
Using the figues in that table, the heat pump only has a performance factor of slightly over 2 (assuming the electric is the same price for the HP and direct) which sounds rather low but without more context difficult to be more specific on. The electric for both appears to be a standard tariff rather then an E7 one that might be used for heating so probably over double what might be charged for an E7 price.

The energy output for oil seems about right at 10KWh/L - the cost is faily volatile, but a quick check on BoilerJuice seems it is around 50p/L so around €600.00.

I seem to recall that a UK ASHP has an average COP of 2.9. Cost wise, as you say E7 would help massively, and provide leccy when the COP is lowest during cold nights, whereas the day rate would hopefully have a higher (on average) COP.

I don't know much about heat pumps, but assume that the COP of GSHP's don't vary day v's night?


Title: Re: Is this correct?
Post by: brackwell on February 13, 2018, 09:06:34 AM
Natural gas is the cheapest.

As Paul says the HP has to be less than that unless off course you fit it in a system not designed for HP

Wood is always difficult to compare as you can never be sure of the quantity and quality of what you are buying.

If i was buying one of these for my fuel supply then i wood choose pellets which are cheaper than suggested ,made to a standard, easy to store and load,in short a reliable efficient heat source.

However if you can forage your own wood or buy fresh wood and store it long enough to dry then go that way as i do.

Ken


Title: Re: Is this correct?
Post by: Eccentric Dyslexic on February 13, 2018, 09:12:35 AM
So with a heat pump like this, at 7degrees outside temp with a cop of 4.3 what would the figure be?

https://www.ebay.co.uk/itm/Samsung-Premium-Air-Source-Heat-Pump/391855916556?hash=item5b3c6ec60c:m:mr0_DxvDAZd8tc89q1n4yMQ

A cop of just over two in the example this chap has given doesn’t really show the heat pump in a good light. Maybe he doesn’t sell heat pumps...?

Steve


Title: Re: Is this correct?
Post by: Stig on February 13, 2018, 09:13:41 AM
One thing not mentioned in that table (apart from the heat pump assumed COP) is the efficiency of the heating appliance.  I know modern gas boilers have claimed efficiencies of over 90% but what's the typical efficiency of a wood burner etc.?


Title: Re: Is this correct?
Post by: Westie on February 13, 2018, 09:17:59 AM
Well I hope the LPG figure is wrong....

I've used this LPG  convertion ratio...

LPG litres to kWh and vice versa (1L = 6.9kWh) or (1kWh = 0.145L)

We use LPG as a backup really, it's similar in cost to E7, we buy bulk LPG at 36p/Ltr  so about 5p/kwh compared with 7p/kwr for E7.  Of course conversion efficiency
play a big factor and for heating water an immersion has a high efficiency while our 30yr old LPG system boiler doesn't  ::) so I guess there's not much in it in our case.










Title: Re: Is this correct?
Post by: Justme on February 13, 2018, 12:07:57 PM
Are they raw input kWh numbers?

If so then wood is wood.

1000kg of chip or 1000kg of logs contain the same kWh at the same % moisture.


Title: Re: Is this correct?
Post by: titan on February 13, 2018, 02:24:22 PM
   Results are published here monthly      http://www.nottenergy.com/energy_cost_comparison/


Title: Re: Is this correct?
Post by: Sprinter on February 13, 2018, 03:50:48 PM
I paid £250 for 4 cubic meters of unseasoned hardwood earlier in the year, i will need to season it for a year in our log store but it will be fine for next winter.

Also have to take down a large Eucalyptus this year and that will season for a couple of years before use, though its not necessarily free as it will cost me £500 to have felled and chopped into rounds.


Title: Re: Is this correct?
Post by: AndrewE on February 13, 2018, 04:14:41 PM
Are they raw input kWh numbers?

If so then wood is wood.

1000kg of chip or 1000kg of logs contain the same kWh at the same % moisture.
I assumed it was the price as delivered, presumably more energy goes into shredding wood and forming pellets compared with splitting logs.
Also the installation costs of the systems (and maintenance costs and depreciation) might vary so much it could outweigh the price per kWhr figure.


Title: Re: Is this correct?
Post by: Countrypaul on February 13, 2018, 05:47:21 PM
So with a heat pump like this, at 7degrees outside temp with a cop of 4.3 what would the figure be?

https://www.ebay.co.uk/itm/Samsung-Premium-Air-Source-Heat-Pump/391855916556?hash=item5b3c6ec60c:m:mr0_DxvDAZd8tc89q1n4yMQ

A cop of just over two in the example this chap has given doesn’t really show the heat pump in a good light. Maybe he doesn’t sell heat pumps...?

Steve

If the heat pump gives cop of 4.3 that is about twice what is quoted in the table, so the cot would be about half so £350. If it was run on E7 electric at say 7p/KWh then the cost would drop by just over half again so £175.

The problem is these are all raw figures and once you take into account all the other factors such as boiler efficiency, heat emitter efficiency, capital cost of the boiler/HP/Stove along with the heat emitters (UFH, Rads, piping etc). the raw figures that appeared so good, suddenly seem a much smaller part of the overall cost.


Title: Re: Is this correct?
Post by: RIT on February 13, 2018, 06:04:18 PM
A general table like that is only going to supply some basic indication costs for anything that has to be delivered as time of year and location will have a major impact.

The best example of the issue I can give is this Which report that looks at UK LPG costs for last October.

    https://www.which.co.uk/reviews/home-heating-systems/article/home-heating-systems/lpg-central-heating

Here they are giving an 'average' cost of 12,000 kWh of LPG at £780, so far less than €1,640 for 10,000 kWh quoted in the table. My guess is that as the prices are in € the pricing is for a location with limited LPG supply, I would also say that the table has been put together by someone who supplies wood based solutions.


Title: Re: Is this correct?
Post by: Eccentric Dyslexic on February 13, 2018, 06:22:39 PM
The chap posted this as gospel, generally true and indicative of what you’d expect to pay here in....France!


Title: Re: Is this correct?
Post by: RIT on February 13, 2018, 06:37:32 PM
The chap posted this as gospel, generally true and indicative of what you’d expect to pay here in....France!

That's the key bit of info as it provides some location info - Very big country with lots of wood resources :)  It could also explain the low COP assigned to the heat pump figure as areas such as the southwest can see very low temperatures over the winter that will result in a Heat Pump being a very poor solution.



Title: Re: Is this correct?
Post by: titan on February 13, 2018, 08:27:21 PM

 It could also explain the low COP assigned to the heat pump figure as areas such as the southwest can see very low temperatures over the winter that will result in a Heat Pump being a very poor solution.



That must be why they are so popular in Scandanavia ?

I posted a link upthread that gives all the data to compare fuel sources.


Title: Re: Is this correct?
Post by: BruceB on February 14, 2018, 02:26:22 PM
I would say the table is not correct for UK.  Here, oil is the cheapest since the price fell about half.  Here are the figures from Jun 16 from Renewable Energy Installer.


(https://s13.postimg.org/t4qugcdpv/Screen_Shot_2018-02-14_at_14.24.32.png) (https://postimg.org/image/t4qugcdpv/)


Title: Re: Is this correct?
Post by: titan on February 14, 2018, 02:36:23 PM
I would say the table is not correct for UK.  Here, oil is the cheapest since the price fell about half.  Here are the figures from Jun 16 from Renewable Energy Installer.


(https://s13.postimg.org/t4qugcdpv/Screen_Shot_2018-02-14_at_14.24.32.png) (https://postimg.org/image/t4qugcdpv/)


Your screenshot gets it's data from the source I posted at the top of the tread The Nottingham Energy Trust.  It is the best source of comparison data between different fuels is updated monthly and been going for years.


Title: Re: Is this correct?
Post by: BruceB on February 14, 2018, 03:36:46 PM
I am surprised kero is as much as 85 cents a litre in the original post.


Title: Re: Is this correct?
Post by: brackwell on February 14, 2018, 04:10:56 PM
I was very surprised to see the low cost of oil except this site has it at 50p/l  https://www.boilerjuice.com/heating-oil-prices/


Title: Re: Is this correct?
Post by: gb484 on February 14, 2018, 08:10:43 PM
The French government in their infinite wisdom increased the tax on heating oil on the 1st Jan 2018 by 45 euros on a 1,000 litre delivery despite the fact that more than 4 million French households have an oil boiler (compared to less than half that number in UK): https://www.fioulreduc.com/blog/hausse-taxe-fioul-ticpe-janvier-2018. Current price is between 80 and 85 cents after reaching around 87 cents earlier in the year, depends on quantity and area.
Energy costs for various fuels in 2017, note that heating oil, fioul, is already more expensive than wood and gas before the increase: https://www.mychauffage.com/blog/cout-des-energies-chauffage. LPG or GPL in France is the second most expensive after electricity.


Title: Re: Is this correct?
Post by: RIT on February 14, 2018, 09:18:21 PM

 It could also explain the low COP assigned to the heat pump figure as areas such as the southwest can see very low temperatures over the winter that will result in a Heat Pump being a very poor solution.



That must be why they are so popular in Scandanavia ?

I posted a link upthread that gives all the data to compare fuel sources.

Well for Norway I think HPs are the primary focus as 99% of their electricity is from Hyro, so making heating by HP zero emission. As part of this they are banning fuel oil for heating projects.


Title: Re: Is this correct?
Post by: Philip R on February 15, 2018, 12:56:59 AM
Brousing the enclosed document in French, I see that they apply vat to the kero at 20%, in the UK it is 5%.
Then the bar stewards  have applied a further 4.5 eurocents per litre. That is like another3-4% on the price, a bit like our excise duty on road fuels.

What was the reason, the punish those who live in the countryside.
Has French diesel duty gone up relative to petrol, I doubt it. Just clobber the minority.
Oil space heating is far better than switching on another electric heater and thus make edf purchase generate peak load using coal and heavy fuel oil.
Philip R

PS I thought the French government used more joined up thinking than hmg does here!