Energy efficiency in historic homes

[Nemesis]

A FREE conference in Edinburgh:

http://www.changeworks.org.uk/content.php?linkid=374

http://www.changeworks.org.uk/content.php?linkid=373

http://www.ewht.org.uk/Forthcoming-Events.aspx

 

[Nemesis]

The OH attended while I did other things in Embra. He reports it as very interesting indeed.

 

[Jon Maine]

So if I am on a green electricity tariff for my heat pumps, what would a hips energy survey make of the Merchants House?

Effectively we are carbon neutral.

Would love to go to conference but just a bit to far and a bit to busy.

 

[Nemesis]

Also as it was Friday you missed it.

But basically it was about the work being done by Edinburgh World Heritage Trust alongside other partners to show that historic buildings can be successfully made more 'green'. Some interesting results!

 

[Flyfisher]

So if I am on a green electricity tariff for my heat pumps, what would a hips energy survey make of the Merchants House?

Effectively we are carbon neutral.

I know what you mean but I'm not sure it's that simple. The implication being that every house could become carbon-neutral by simply signing up to a green tariff electricity supplier and changing over to electric heating. I doubt this would work in practice, given the present state of renewable generation.

It would be interesting to know more about the supply and demand figures for these 'green' electricity companies . . . the case of one forum member (can't remember who) that receives credits for a wind turbine not even connected to the grid makes me wonder.

I suspect the biggest real factor in domestic heating is how the occupants behave. Two identical houses could have vastly different energy usage depending on the occupants. Same with cars actually; a 'gas guzzling 4x4' doesn't emit any greenhouse gases when not being used yet the government's approach seems to be to tax the potential (e.g. car tax and soon, apparently, 'showroom' tax) rather than actual pollution, i.e. tax the fuel not the car. I wonder how long it will be before houses are taxed based on their energy 'ratings', regardless of how much fuel the occupants actually use?

 

[Jon Maine]

Thats a scary one when I have heavily invested in a system which is carbon neutral.

 

[Nemesis]

I wonder how expensive/inexpensive it will be Jon? Presumably the energy used is the electricity for the pump, that's all.

 

[Jon Maine]

The energy used is purely to move and condense the heat, not create the heat, should produce a return of 3 to 4 kw of heat for 1 kw of electrical usage. So by current standards a very efficient heating system.

 

[Flyfisher]

Yes, it's 'only' the pump that uses electricity but that doesn't mean it's a small amount. It would be interesting to know the rating of the pump motor and even more interesting to know how much actual electricity is being used by the system.

Electricity is much more expensive than other fossil fuels (hardly surprising since it is mostly generated from them at rather less than 100% efficiency), so the 300-400% efficiency of a heat pump system really only brings it into line (roughly) with the price of oil and gas, which as we all know is not cheap!

My figures for gas CH and DHW (4-bed detached) suggest a yearly average consumption of 100kWh/day. Even allowing 400% efficiency, this would suggest 25kWh per day (average) of electricity for a heat pump, probably nearer 30kWh/day.

Last time I checked, electricity was about 13p per kWh and gas was about 3p kWh, or about 4.3:1. Of course, electricity can be converted to heat with 100% efficiency whereas new gas boilers are supposed to be around 90% so that makes the cost/kWh ratio pretty much 4:1. Thus, a 400% efficient heat pump can be expected to cost the same to run as a gas-fired system.

 

[Jon Maine]

Sounds reasonable, I am counting however on the fact little or no maintenance costs should also help the equation.

I am still using power tools regularly so an indication of true cost is not yet available especially as we have only recently installed the underfloor heating upstairs.

But of course where things should get better is when oil and gas spiral more as they will.

Personally I would like to establish an anaerobic biodigester locally powering a generator or series of. There is a scheme in Germany which gets through 60m3 of cow muck and 10 tonnes of food waste a week supplying power for 500 homes and a business park. I can see that small generation schemes like this widespread would be a good way to go. Of course it efficiently processes foul products into fertilizer as a by product too. Hopefully we will see more of it since the Archers latcher on to it on good old radio four. See http://www.new-agri.co.uk/02-4/develop/dev02.html

 

[Lime]

But of course where things should get better is when oil and gas spiral more as they will.

Are you saying that you think that oil and gas prices will rise but electricity won't?

I doubt that very much.

 

[Jon Maine]

Not that it will not rise, but it is possible to produce electicity without burning fossil fuels.

Certainly if I get a local biodigester online cost of electricity will not concern me.

After the merchants house another project will be required, as yet undecided but perhaps a generation scheme would be good.

 

[Flyfisher]

Long term, I agree with Jon that electricity will (have to) become disconnected from fossil fuels and generated from renewable sources, although that still may not make it particularly cheap - how will we build generating plants without fossil fuels? It might become a very, very expensive process.

Short term though, I agree with Lime; electricity will be largely dependent on oil and gas for quite a while yet and while it remains so then it's bound to be more expensive (unless governments mess about with taxes).

As to the timescales of 'short' and 'long' term, I've no real idea. But I can't honestly see renewable energy generation becoming a significantly large proportion of our total capacity in the next 10 years or so such that it could alter our energy economics - and that's time enough for my new gas boiler to last.

It's all a bit of a gamble, of course, although a gas (or oil) boiler is only a £1000 gamble instead of a £10,000 heat-pump gamble (roughly), so I'm happy to hold on to my other £9,000, sit it out for 10 years or so and revisit things again when I need a new boiler. And heat pumps might well be much cheaper and more efficient by then as well!

 

[Lime]

Disconnected from fossil fuels or not I can't see electricity ever being "cheap" to use.
The competition electricity has with oil and gas keeps a lid on it's price.
As soon as the fossil fuel prices rise electricity will rise, connected or not.
Without a direct comparison of energy we would be paying far higher prices than we do.
The only way electricity can become cheap (in the sense it does not cost much to consume) is to generate it ourselves.
However there will always be the huge expense of intial installation, maintainence and eventual renewal.
Also the majority of consumers are not in a position to become self-sufficient in any way at all.

The nirvana combination of self-sufficiency and high life style is only able to be maintained by a rich few now and in the future they will have to be richer still.
It is based on the "outside" world producing goods to generate both their cash and the goods.
Unfortunately, unlike the generators of the past (1920s-1940s), most modern machines are built with a finite life and are rather delicate so will not last long.

 

[Nemesis]

A bold experiment Jon - will be interested to see how it all works.

Some have to be in the vanguard...

 

[Flyfisher]

Disconnected from fossil fuels or not I can't see electricity ever being "cheap" to use.
The competition electricity has with oil and gas keeps a lid on it's price.
As soon as the fossil fuel prices rise electricity will rise, connected or not.

Interesting points, although if renewable sources really do become widespread then, presumably, the various 'green' generating companies will compete among themselves to sell the cheapest electricity? But I take your point that they might well use the fossil fuel generated cost to provide the market pricing yardstick. So much for the promise of "electricity too cheap to meter" that was heralded by the nuclear industry!

The only way electricity can become cheap (in the sense it does not cost much to consume) is to generate it ourselves.
However there will always be the huge expense of intial installation, maintainence and eventual renewal.

Agreed, and that capital cost divided by operating lifetime defines the lower limit on the real cost of self-generated 'free' electricity. There is no escaping the fundamental economics, only the method of paying will vary.

Also the majority of consumers are not in a position to become self-sufficient in any way at all.
The nirvana combination of self-sufficiency and high life style is only able to be maintained by a rich few now and in the future they will have to be richer still.
It is based on the "outside" world producing goods to generate both their cash and the goods.

Absolutely right. Self-sufficiency is nowhere near the same as true independence.

As for some being in the vanguard of new technologies, I entirely agree. All early adopters take on significant risks, both financially and technically, and relatively few people are able or willing to do this, although it's to the benefit of us all that they do. My first digital camera was 2 megapixels and cost £650 in 2000. Eight years on, such a specification is laughable and the sort of thing given away in Christmas crackers (well, almost!). Hardly the same scale of risk as a 'green' energy system, I accept, but it's indicative of how fast technologies can develop and the financial risk of getting it wrong.

 

[Penners]

one forum member (can't remember who) that receives credits for a wind turbine not even connected to the grid

Jane Smith isn't it?

 

[Jon Maine]

I do have an opportunity to get involved on a local farm where an outside event happens each year, well most years. Sadly whilst it may not be possible to store an process all of the effluent from the event there are at least 700 cows in the same valley.

I do have a good mentor from Greenpeace who is keen to see this scheme develop who also has links to such said event.

If power is generated locally with many smaller generation plants it should be more efficient in terms of transmission loss.

Anyhow, something that is an option to me and worth exploring on many levels.

It does seem to be the case that we will still rely on having to create high levels of heat to process metals etc which would obviously require fossil fuels. What other options could there be? Although am I right in thinking some blast furnaces are electric?

Any how I will be glad to see how my heat pumps run through next winter, I firmly believe that they will be cheaper to run than a gas system.

 

[Lime]

It does seem to be the case that we will still rely on having to create high levels of heat to process metals etc which would obviously require fossil fuels. What other options could there be? Although am I right in thinking some blast furnaces are electric?

Many metal furnaces are heated by electricity, aluminium for one, but the process is profligate with electricity.
that is why most electric smelters are built next to hydroelectric dams etc.
But then there is the mining of the ore ...........

Any how I will be glad to see how my heat pumps run through next winter, I firmly believe that they will be cheaper to run than a gas system.

As I am sure you know, the efficiency of your heat pump is directly related to the source temperature (usually the ground outside) and the insulation within your home.
A long cold hard winter would produce a less efficient result.

I don't think power generated locally would supply either an efficient service or be practical for the majority of the population in this country.
In general, nationally, transmission losses are small compared to the losses produced by a multitude of small and separated generators.
The grid losses are made up for by the efficiency of large generation plant and the grid allows use of diversity (the varied and different expected consumption by users at any one time) to increase efficiency.
Diversity plays a very big part in the economics of the generation of electricity which is often overlooked.

 

[biffvernon]

If power is generated locally with many smaller generation plants it should be more efficient in terms of transmission loss.

I think too much is made of transmission losses sometimes. The UK grid runs at about 7% loss, and much of that is in the low voltage local distribution part. If/when we have high voltage DC grids bringing solar power from Africa, they's be running at less than 1% loss per 1000 km.

Not that that is in any way an arguement against generating as much electricity from local renewable sources as possible. We're going to need every last Joule we can find in the years ahead.