COAL

[mikepepler]

I've been heating the house almost exclusively on coal, and it's been going quite well so far. The ?/BTU of hardwood is about he same as coal, but I don't see burning wood as remotely sustainable.

So if burning wood isn't sustainable, how is burning coal better? Can't you get your wood from a sustainable source?

[snowdrift]

Most of the wood I can get locally comes from tree surgeons. I've no idea if people are planting new trees in their gardens as quickly as they are having old ones chopped down or not. But, while I might be able to get wood from a sustainable source, what's sure is that not everyone can. There's not enough land to grow the trees required for everyone to burn wood.

At the end of the day I'm far more concerned about rising energy prices than rising CO2 or rising global temperatures.

What we can be sure of, is that if oil and gas start to fail the price of firewood will go up pretty fast.

[snow hope]

I've been heating the house almost exclusively on coal, and it's been going quite well so far. The ?/BTU of hardwood is about he same as coal, but I don't see burning wood as remotely sustainable.

I'm currently using a simple iron stove, but I'd be interested in modern domestic coal furnances. Has anyone had experience of them?

Hi Snowdrift. My mother used to have a coal fired central heating boiler in a house in Belfast during the nineties. You had to replenish it a couple of times per day from memory but it seemed to work fine. She replaced it with an oil fired boiler when the coal boiler sprung a leak.

I am looking to replace my oil boiler and I am seriously considering a wood log boiler - see the Biofuels section for more...... but now you have brought it up, I wonder can you get a boiler than will burn wood logs and coal if you so choose? That would be pretty flexible then.

[mikepepler]

Most of the wood I can get locally comes from tree surgeons. I've no idea if people are planting new trees in their gardens as quickly as they are having old ones chopped down or not. But, while I might be able to get wood from a sustainable source, what's sure is that not everyone can. There's not enough land to grow the trees required for everyone to burn wood.

Agreed, but at present only about 25% of the UK's sustainable level of wood fuel production is used (I did some research at work for this), so there's plenty of scope at present for more people to burn wood. Once all this wood is being used, then the next step should not be coal, but ground-source heat pumps running of renewable electricity. Granted that this assumes the renewable electricity capacity gets built, and of course I'm assuming that people insulate their homes as best they can before looking at energy consumption.

What we can be sure of, is that if oil and gas start to fail the price of firewood will go up pretty fast.

I hope so - that's why we bought a wood!

[snowdrift]

That's interesting - didn't know we had that much wood left in the UK. I've often considered buying woodland, but more because I like it than because I want to harvest it for heat or timber.

Woodlands (or at least the ones on woodlands.co.uk) don't seem to be great value at the moment, however.

[mikepepler]

That's interesting - didn't know we had that much wood left in the UK. I've often considered buying woodland, but more because I like it than because I want to harvest it for heat or timber.

Here's a paper I wrote on it. The figures are a little our of date now, but are broadly correct.
http://www.ashdenawards.org/files/wood- ... _paper.pdf

Woodlands (or at least the ones on woodlands.co.uk) don't seem to be great value at the moment, however.

Well you get what you pay for. We paid about ?5k/acre but we got a load of 10-15 year old chestnut coppice, about 15 100-150 year old oaks per acre, relatively flat land, good access and a nice market town 4 miles away to go and live in. The whole wood was basically ready for us to start managing and we will earn money from it this winter. It's also got quite a lot of wildlife, which we will be trying to encourage.

On the other hand, there were woods from them (and others) at ?2-3k/acre, but they were usually on a steep slope, miles from anywhere to live and covered with coniferous trees. Now that doesn't mean they're no good, but if you want a coppice, it's a damn sight easier to get one already established. Otherwise you have to put in a lot of effort, some money, and then wait a number of years before you have anything worth harvesting. Also, if you start with conifers, you might end up buying machinery to harvest them and making contacts that won't be so useful once you have a coppice going.

It all depends what you want it for.

[Ballard]

Mike,

Whilst I agree that wood is the way to go in the short term, (and I use it every night to heat one room of my house in which we spend the evening), what percentage of the UK housing could be sustainably heated by wood fuel in the UK do you think ? (let's say 18 degrees)?

[mikepepler]

Whilst I agree that wood is the way to go in the short term, (and I use it every night to heat one room of my house in which we spend the evening), what percentage of the UK housing could be sustainably heated by wood fuel in the UK do you think ? (let's say 18 degrees)?

Without checking the figures, I'd guess 10-20%? Perhaps that could be increased if they were all properly insulated.

I think we need three approaches at once to heating:
- insulate to a high standard
- use all the sustainable wood fuel we can
- use ground source heat pumps for the rest of the demand, but this implies sufficient renewable electricity to supply them, and grid connection upgrades where required (i.e. Scotland to England, and we'll have to ask the Scots nicely about that...)

This is the only way I can see us getting off fossil fuels for heating. Our rapidly declining gas supplies mean the above approach, or something like it, is necessary for energy security in the UK.

Any thoughts?

[Ballard]

This is the only way I can see us getting off fossil fuels for heating. Our rapidly declining gas supplies mean the above approach, or something like it, is necessary for energy security in the UK.

Any thoughts?

It?s certainly a tough one!

For new build there seems to be a simple method that works for almost all situations, the German Passive house standard.

http://en.wikipedia.org/wiki/Passive_house

Simply put, super insulation, extremely airtight, and then draw incoming air through pipes in the ground to pre-temper it towards 14 degrees (cool air in the summer, pre-warmed in the winter). This passed through an air to air heat exchanger should reduce energy requirements by 95% (with quite a high degree of user input, always the difficult bit!).

For our current housing stock which is 99% of the problem, I?m more concerned.

The government should totally subsidise the upgrading of houses with insulation and air tightness measures, (then small localised air to air heat exchangers in ?wet areas?). Possibly a better use of money than chucking it at failed banking businesses!

Then introduce electricity and gas pricing on a Rising cost scale, the more you use the greater the cost per KW or Therm, this would instantly discourage waste and promote frugality.

People may then get used turning down the stat and wearing jumpers.

Then sustainable wood fuel, logs are simple, woodchip tricky, pellets too techno, and live more like your grandparents in chilly houses, with one room heated in the evenings.

Ground source heat pumps don?t do it for me.
You need a very well insulated house first, upgrading an existing house is extremely difficult and expensive and if you manage it then you are replacing gas (lowish carbon) with electricity (very high carbon) the 60% carbon savings you make in the home are lost in the power stations. You are totally reliant on a non-intermittent grid, and unless you can show me otherwise I?ve yet to be convinced that there will ever be enough electricity from renewables to meet our current consumption never mind the additional load of home heating.

So, I think we have a huge problem, called population. At the end of the day when people are spending too much on their heating, they will leave the house with a saw and a wheelbarrow and return whatever wood they can get hold of.

On the bright side, an unheated house in the UK is not totally unliveable, for the fit and healthy, a bit more of a challenge for the old an infirm.

[RenewableCandy]

Whilst I agree that wood is the way to go in the short term, (and I use it every night to heat one room of my house in which we spend the evening), what percentage of the UK housing could be sustainably heated by wood fuel in the UK do you think ? (let's say 18 degrees)?

Without checking the figures, I'd guess 10-20%? Perhaps that could be increased if they were all properly insulated.

Agrees with the '30% of domestic heating if you turn all the set-aside over to SRC as well' figure that I came up with in a project for my MSc, fwiw.

[Andy Hunt]

Problem is, not all the available wood will be available for heating domestic homes - doubtless there will be industrial users after it too.

(like that nice new biomass plant in South Wales for example . . .)

I think heat pumps (air- or ground-source) could prove very popular for most homes.

[mikepepler]

Ground source heat pumps don?t do it for me.
You need a very well insulated house first, upgrading an existing house is extremely difficult and expensive and if you manage it then you are replacing gas (lowish carbon) with electricity (very high carbon) the 60% carbon savings you make in the home are lost in the power stations. You are totally reliant on a non-intermittent grid, and unless you can show me otherwise I?ve yet to be convinced that there will ever be enough electricity from renewables to meet our current consumption never mind the additional load of home heating.

That's why there should only be a big move to them if renewable and grid capacity is built at the same time. I've come to think they have to be part of the solution simply because if, after insulating, there is still more heat demand than can be met with biomass, then it has to come from somewhere. If it's not going to come from imported gas, fuel oil or LPG, then it has to be electricity.

In the meantime though, what about this: a CCGT power station has an efficiency of 50%, or maybe a little more. Gas burned in a home heating system can never have an efficiency above 100% (obviously). However, heat pumps can output 3-4 units of heat for every unit of electricity in. So... this means that, roughly speaking, if you burn the gas in a CCGT and then use the electricity to run a heat pump, then for every unit of energy in the gas, you get 1.5-2 units of heat.

So doesn't that mean we could use more heat pumps now and actually cut overall gas use? That would buy a little time while renewables are built to replace declining gas supplies.

Of course, making it happen is another matter, as at present using gas for heating is cheaper than using a heat pump.

[Ballard]

Ground source heat pumps don?t do it for me.
You need a very well insulated house first, upgrading an existing house is extremely difficult and expensive and if you manage it then you are replacing gas (lowish carbon) with electricity (very high carbon) the 60% carbon savings you make in the home are lost in the power stations. You are totally reliant on a non-intermittent grid, and unless you can show me otherwise I?ve yet to be convinced that there will ever be enough electricity from renewables to meet our current consumption never mind the additional load of home heating.

That's why there should only be a big move to them if renewable and grid capacity is built at the same time. I've come to think they have to be part of the solution simply because if, after insulating, there is still more heat demand than can be met with biomass, then it has to come from somewhere. If it's not going to come from imported gas, fuel oil or LPG, then it has to be electricity.

In the meantime though, what about this: a CCGT power station has an efficiency of 50%, or maybe a little more. Gas burned in a home heating system can never have an efficiency above 100% (obviously). However, heat pumps can output 3-4 units of heat for every unit of electricity in. So... this means that, roughly speaking, if you burn the gas in a CCGT and then use the electricity to run a heat pump, then for every unit of energy in the gas, you get 1.5-2 units of heat.

So doesn't that mean we could use more heat pumps now and actually cut overall gas use? That would buy a little time while renewables are built to replace declining gas supplies.

Of course, making it happen is another matter, as at present using gas for heating is cheaper than using a heat pump.

Right... I see your point...

In an ideal world we would be able to swap over to heat pumps...

However as we have discussed the issue is existing houses, the cost and practicality of converting these to work with CSHP is very high and generally not really viable for most propertys.

Solutions are very hard to find, home heating will be a bit like private transport, limited for most of us, still avalible to the rich. You should be able keep warm enough with your own private fuel source (I might have to pop round for an extended visit if TSHTF)