Geothermal revisited

iplogger1

In the build planning stages for our 250sq metre (2700ft sq) 2 storey house on 1 acre in the West.
We've more or less decided on installing UFH on both floors and I've met and spoken with folks who've done likewise but used geothermal as the energy source. I've seen the heat pump and it is a neat system and there is a certain initial wow factor in that you have no physically delivered fuel to heat the house.

However ! I still cannot see a cogent enough argument to give me a warm and fuzzy feeling about the payback interval for the heatpump/collector investment. Originally when I read about geothermal I heard 6-8 yrs payback being mentioned. However, having spoken to these folks who have the system in (and who are going to be naturally defensive about their decision to a certain degree) the sums don't stack up particularly well. Both are in houses which have 2700-3000sq ft living space and they would estimate 1700-1800 Euro would have been their annual oil bill at current prices. I think 1300 Euro would be their electric bill for annual consumption on the heat pump. Just on basis of fairly crude calculations I would say we're talking about 20 yrs payback. I'm not going to speculate on oil price curve versus ESB for the next 20 yrs (or I'll have to award myself Nobel prize in Economics) but I can't see the cost curves diverging wildly over that interval. If and when there is an energy crisis both will be driven up. So a 14k or so additional capital investment for geothermal versus a conventional oil burner to me looks like an inconclusive bet as far as payback is concerned. I also wouldn't bet on night saver electricity being as attractively priced as it is currently as we move into the next decade.

Feel free to rip apart my conclusions. They are mostly gut feelings based on early stories from folks who have GSHP in a few months or 18mths in one case so they my findings are not hugely scientific.

My current line of thinking is to insulate to the nth degree, install a conventional oil boiler but reserve enough space out the back for the potential of maybe switching to wood pellets should the economics of wood pellet versus oil become more obvious. I'm also very keen to put in solar heat collector system for DHW for summer months.

~ipl

Gurgle

iplogger1 wrote:

they would estimate 1700-1800 Euro would have been their annual oil bill at current prices.
I think 1300 Euro would be their electric bill for annual consumption on the heat pump.

Somebody has been screwing up heat pump installations tbh.

I looked into this tech last year, seriously considering it as a business start up. Considering Ireland's climate et all, you should be looking at approx 1/3 the running cost compared to oil. 1300:1800 is worse than 2/3.

The market certainly appears to be occupied in Ireland by people who know lots about central heating and sfa about heat exchange.

Wobs

Hi guys,

I just heard today that their are grants coming in for GSHP's from next Monday, possibly up to 25% of cost of installation. Worth keeping an eye on if the cost is putting you off!

yop

any source about these grants? SEI have nothing

Wobs

From a supplier. Sorry to say yop they won't be back dating, it will only be for people who get them installed after the 27th.

yop

I thought that, BUT I presume u present them with the invoice of the date of purchase to get the grant?

iplogger1

Gurgle wrote:

Somebody has been screwing up heat pump installations tbh.

I looked into this tech last year, seriously considering it as a business start up. Considering Ireland's climate et all, you should be looking at approx 1/3 the running cost compared to oil. 1300:1800 is worse than 2/3.

The market certainly appears to be occupied in Ireland by people who know lots about central heating and sfa about heat exchange.

I'm no expert but the impression I got was that if anything Ireland's climate is less matched to the efficiencies of geothermal than, say, to the climates where it is already well adopted (eg, Nordic countries). As I understand it geothermal is a misnomer in terms of how it is typically implemented on these shores and the most efficient way of harvesting geothermal energy would be to have a vertical bore hole (requires extensive site survey and highly dependent on placement of water table and depth of water table, etc)
for collection of the true geothermal energy.

~ipl

sas

On the grants, I spoke to Dunstar at the Spring homes and garden show in the RDS at the weekend. They told me that a grant of 2K towards the horizontal collector type system and 5K towards bore hole were due in the next 2 weeks.

As to how true this is I don't know.

rooferPete

Hi sas,

The figures have not been decided regarding Any Renewable Energy System.

.

Gurgle

iplogger1 wrote:

Ireland's climate is less matched to the efficiencies of geothermal than, say, to the climates where it is already well adopted (eg, Nordic countries). As I understand it geothermal is a misnomer in terms of how it is typically implemented on these shores and the most efficient way of harvesting geothermal energy would be to have a vertical bore hole

Yep, you're absolutely right. A more accurate term is 'environmental heat exchange'.
An air-source heat exchange would probably be the most efficient here, followed by a shallow trench but you would also have to consider the availability of ground-water. If theres water seeping through the soil where the pipes are you could get great efficiency but otherwise a vertical bore-hole would be pointless.
A badly planned system would effectively be heating your home with an electric immersion tank, which could cost more than oil to run.

dras

Hi iplogger,

You should look again at the economics of a wood pellet boiler - they do add up! I am with you on the "geothermal" system - v expensive and you still need a significant electricity spend. Wood pellets are much cheaper and straightforward technology.

iplogger1

Dras,

Yes I'm definitely looking closely at the economics of the pellet boiler systems.

Someone just posted a query about the space required to store 3tonnes of pellets as well as query on guidelines as to where to place a boiler (inside/outside house). I'm interested in seeing the replies to those questions.

A guy who I know put in geothermal raised arguments against pellets by saying that he felt the current cost of pellets was questionable and he felt they were being sold close to cost as part of getting early adopters to a critical mass to make the adoption more mainstream .. and he predicted their cost would rise with wider adoption. I am sceptical when I see a suppliers literature claiming that the pellets are not subject to price sensitivities due to fossil fuel energy crises. 3 tonne loads to be delivered from Fermanagh to the distributor to your door sounds like there are inevitable transport costs involved and I'm sure a good deal of energy is consumed in the re-constitution of the sawdust material into pellets. So it would be truer to say that they might have a less direct dependancy on oil/fossil fuel price variations. I'm a little concerned about the dryness requirement for the pellets but I've been fairly reliably assured that animal feed delivery systems in this country have stood the test of time with regards to the Irish climate so concerns over difficulty of dry storage are probably unfounded.

Can anyone add their 2 cents to the pros/cons of wood pellets?

~ipl

rooferPete

Hi IPL,

I do know that top quality bagged pellet fuel can be purchased in Europe cheaper than we are paying for the fuel delivered in bulk.

The prices including delivery to Dublin Port in container loads are so attractive that when the demand for pellet fuel increases I expect a lot of suppliers of existing fuel like coal will be including pellet fuel in their range of products.

I have been to Balcas and was given the full tour by the Peter Kernohan, the process is truly amazing, it is about as close to perputal motion as I have seen.

The waste is dried causing steam which drives their electricity generators, some of which they sell to the N.I. electricity grid, when the waste is dried it goes back into the furnace to dry the next batch of waste.

A side effect of this process is a lot of heat which is used to dry the saw dust as it is graded through the machines and compressed into pellet fuel, as the fuel is being carried up to drop into large storage silos the majority of the saw dust is recycled by vacum into the compressor and it becomes part of the next batch of pellet fuel.

I hope you will forgive me but I do realise I am missing out on a lot of detail and not using the correct terminology, but my tour lasted over four hours and I was very lucky to be the only one there on the day.

The down side is you must keep the fuel dry which means you will need a weather proof storage tank or a dry shed and a storage tank made out of timber.

At the moment I know one possible supplier researching and designing a cost efficient fuel storage tank made out of timber for easy assembly in Ireland, another Irish company is doing research using material suitable for outside use.

There are a lot of small joinery's in Ireland who are paying to have the saw dust removed and disposed of as waste, so the potential is here for an enterprising company to begin making pellet fuel.

.

Pataman

What about an underground bunker?

iplogger1

Actually I was talking to someone this week who knew a thing or two about heating systems and renewable sources and he suggested an underground bunker perhaps a subfloor within a large garage/shed in a new house build.
He maintained that there are companies who will sell containers which hold the 3 tonne deliveries but that you will save a lot by going DIY and the subfloor idea was something he touted.

One thing that still leaves me slightly uneasy (laziness I suppose) is that it seems that the standard hopper feed for pellet boilers will hold a reserve of say 5-6 days (maybe slightly more) worth of pellets. So, there is a manual backfeed operation which one has to do all the time to ensure the hopper has a couple more days supply. I guess oil is more convenient in that respect and geothermal even more so (since you never need to worry about a refill) but you (and the environment) pay for that luxury.

Have I crossed wires here or is there some magic way for a householder to store 3tonnes of pellets and have them autofed into the boiler with little or no manual intervention other than when the supplies are down to the last few days worth before the next big (eg, 3tonne) fill ?

~ipl

CJhaughey

an Archimedean screw, will provide the transport for your pellets.

rooferPete

Hi,

There is an underground storage tank available that works using a vacum system, I do have mild concerns with anything buried that fully depends on another motor not to mention the cost of running the vacum system.

A hopper system should last a couple of weeks without causing any major problems of course the capacity of the hopper is a factor.

It is possible to fit an auger to either an external galvanised steel storage tank, the same can be done with internal timber storage systems.

I do understand that people want the automated system nearest to oil that they can get however bear in mind extra augers are more expence at the beginning and the operating costs should be taken into account.

One very important thing to take into account is Balcas do require two weeks notice for bulk deliveries so it's not like your oil where there are a lot of trucks on the road waiting for a call to deliver more fuel.

The advantage of spending an hour (or less) topping up your hopper manually is you also get to monitor your fuel level and average usage, so you avoid running out of fuel and buying in bags while waiting on a delivery.

.

Qwerty?

We have a geothermal system and average running costs per 24hr is €5. (summer runnings costs should be way less & that's not counting our nightsaver) That's to heat an open plan 3500 sq ft house. You also have to remember that's 24 hour heat and hot water, 7 days a week, pellets or oil could never match that.

Yep, it's expensive to install.... not as expensive as it is for ye now thou, thanks to the grants.:mad: don't apply to me , installed in nov 05.

iplogger1

Qwerty? - Thanks for the info.
I've sent you a PM (boards private msg)

~ipl