Hi

[tilpol]

Hi

 

After reading the forum for a while thought it was about time to introduce ourselves. Having bought some land earlier on this year we are now just about to start the process of getting planning permission for our build. The build is off the west coast of Scotland so does have its challenges:

 

Accessibility

Needs a ferry journey plus a 3 miles trek across a single-track road to get to the plot. So no large lorries, cement lorries. There has been a number of self builds around the island so not impossible just need careful planning. Does make everything you do more expensive.

 

Water

No mains water, supply comes from a spring 

 

Electricity

There is electricity available but I can't grid-tie any PV I put up. I want to generate some of my own electricity so both systems would have to be isolated. 

 

Main thing we've been looking at just now is the cost for the structure so have been getting quotes from timber frame and SIPs suppliers. Some of the SIPs quotes I've been getting have been very expensive so will probably go for a timber frame. Now need to decide on which one although I need to look at where I can save cost. Initial plan is to get structure wind and watertight then carry out most of the work myself, probably with the help on neighbours.

 

I can post my initial plans for people to look at if people are interested.  Looking for suggestions on where I can reduce cost.

 

 

[Tennentslager]

Welcome, folk will be happy to comment on plans, might also be useful to include a block plan for consideration of orientation on the plot.

Which island and does the equivalent road tariff apply? Quite a few island dwellers on here with experience of our lovely variable weather ????

[bissoejosh]

Hi, sounds exciting!

 

I'd suggest choosing your wall / foundation detail as early as possible as that eliminates a lot of follow on decisions nice and quickly. Save costs by using cheaper but perfectly suitable materials (EPS instead of celotex for example in the ground) and allow for the additional amounts required to get the same end result (digging deeper / thicker walls etc) assuming space isn't an issue. We've found that there is a huge difference in SIPS/timber frame prices and have opted for an engineered i-beam timber frame which we'll assemble ourselves.

 

What is the ground like where you intend to build?

Edited January 13, 2018 by bissoejosh

[ProDave]

Hi and welcome.  I would be interested to know which island you are on? and why can't you grid tie to the electric supply?

 

Due to the access issues, have you considered building the timber frame on site? then it's just raw timber to get to the site.

 

Have you got accommodation to live in during the build? I suspect a static caravan is out of the question?

 

Presumably there is local transport available to get stuff from the ferry to your plot?

[tilpol]

Hi

 

Thanks for the quick replies I'll try and answer your questions:

 

The plot is is on a slope (about 5 degrees) and has about a 1m of sandy clay before hitting bedrock. The front of the house will face west, I've attached a picture of the view looking west.

 

It is on the Isle of Eigg they have their own integrated renewable energy system (solar, wind and hydro) that supplies electricity to the island. Each house can take up to a maximum of 5KW from the grid. As this is not the national grid but a small self-contained system run by the island at present there is no possibility of individual house being grid-tied to it.

 

Building the timber frame on site is very much something I want to consider. Has anyone got any contacts for this so I can explore the possibility. I have only spoke to timber frame kit manufacturers so far.

 

This summer we hope to be in a position to get the access road laid and build a self-contained office at the bottom of the plot which we will use for accommodation during the build which I will eventually use to work from.

 

Bulk materials are usually brought across on a local landing craft then there are various vehicles around to take the material across the island.

 

I've also attached our current idea for the build. 

 

Thanks

 

Elevations.pdf

Roof Plan & Section.pdf

Floor Plan.pdf

[Ferdinand]

Looks really good and generous.

 

But I admit I am slightly suspicious of these universally sunny pictures from Scottish Islands !

 

If we were to believe the "sample" it never blows or rains, and you would all be in wall-less grass huts wearing loin cloths to help you tolerate the searing heat.

 

I feel a distinct echo from "see the seals" seal tours I have been on in various places, when the only seal you see is the one in the promotional photograph.

 

 

Ferdinand

[ProDave]

Hi again

 

I did wonder if you were on one of the small isles, my other guess was the the Knoydart peninsula and the settlement around Inverie (I am sure there was a plot for sale there a while back)

 

Stick building on site is not a problem.  My frame was detailed by an architectural technician and a structural engineer and a full set of plans drawn for the building warrant. It was then built by a local building firm who built the frame in sections in their workshop and brought them to site. It would only be a very small step from that to build the frame on the island.  It would be handy if there was a nearby barn or steading they could rent to give covered work space (the sun does not always shine on the west coast)

 

I am guessing things like concrete will be mixed on site. I hope there is at least one digger on the island available for hire.  Hopefully with a breaker otherwise getting a hole deep enough for a treatment plant will be a challenge.

 

I know you have a private electricity supply but from a technical point, I can't see why a small amount of solar PV export would be a problem. Yes if every house had solar PV it might be an issue. But if you take steps, like excess power  to water heating etc, or even in extreme to a dump load heater, I can see no technical problem.  If you keep the solar PV off grid you are talking of battery storage so I will be interested in your thoughts on that.

 

This sounds like a really interesting project, with it's own challenges due to location, but I suspect a fantastic community to muck in and make it work. I look forward to seeing it progress

 

 

[Mr Punter]

Population = 105 so don't fall out with the neighbours!

[Ferdinand]

48 minutes ago, Mr Punter said:

Population = 105 so don't fall out with the neighbours!

 

Unless I suppose 79 of you fall out with the other 26, as you then have the requisite dominance necessary for an amphibious assault from the sea.

[Tennentslager]

What's a 'storage wall' and the 'ward' above it...?

Haven't heard these terms before.

Building in the middle of nowhere isn't as hard as our forebears endured... battery power tools are truly wonderful things? a bit of thought and once your out of the ground it's not so bad.

Is it a spring/summer build this year..guess planning should be straightforward given location

[tilpol]

Try and respond to some of the comments.

 

Not to worry we've been going to Eigg since 1990 so know all the advantages and disadvantages (weather, people etc) of living there. We have friends on the island so will have support in getting this done and there has been quite a few self builds on the island so there is a pool of knowledge to call upon. For instance there is a digger and driver on the island who I've already used to get the trial pits dug. I think there is a cement mixer which attaches to the rear of a tractor which I will investigate the next time I'm up.

 

Regarding PV the rules at the moment are no private PV is allowed to be connected. Something I will discuss with them over the next year to see if there is anything we can do. If not I will have batteries which can be topped up from the island grid when needed. Still a bit of work to be done on this to develop the ideas further. 

 

"Storage wall" and "Ward" are just built in storage cupboards and wardrobes the full height of the wall.

 

 

 

 

[TheMitchells]

Looks like a really interesting build!  We did a renovation recently which did not have vehicle access - we had to barrow everything in and out of an alley for 80metres. The OH said never again!  It did add to the costs and a huge amount of time and effort.  Sounds like your build will need even more planning and effort - good luck.

[jamiehamy]

We're booked to visit Eigg for two nights in a few weeks! 

[Cpd]

Great looking project, i was sailing round Eigg this summer and used to help the gardener way back  when  Schellenberg owned the place......  many great experiences there and my first real bad experience with whiskey..... teenage years. Look forward to seeing the build come together.    

[Jeremy Harris]

Welcome,

 

The problem with small grids like this is that they have no "spinning reserve" so there is no big "virtual flywheel" to maintain grid frequency, and no energy storage.  The limited frequency stability of the system on Eigg comes solely from the hydro plus some small battery storage capacity and a back up diesel gen set, as both the wind and PV will be going up and down like a yo-yo.  There's no way a grid tie inverter will lock into such a system without changes to the way the hydro plant and battery storage adjusts for variations in PV and wind generation, unless the island invests in either a lot more battery storage (to create a bigger "virtual flywheel spinning reserve") or perhaps something like hydro pumped storage. 

 

My guess is that more battery storage may well be in the long term plan for the island, or perhaps conversion of some of the hydro to pumped storage, to achieve the same effect.  In some ways the problem is a bit like that in South Australia, on a much smaller scale, where inadequate spinning reserve, due to a high reliance on renewables and inadequate maintenance of the reserve generation, led to grid collapse when there was a sequence of unintended generator failures combined with reduced renewable output.

 

As I understand the micro-grid on Eigg, the base load is handled by the hydro, backed up by the batteries and the diesel back-up generator, which can be throttled up and down as the PV and wind vary, so the hydro is acting as the frequency stabilising factor on the grid.  A normal big grid relies on several phase locked fast response power stations to do this, hence the term spinning reserve.  When there is enough wind and/or PV to meet the base load then the hydro and/or the battery storage can throttle back, and perhaps some of the wind turbines can be braked, but the system will be very sensitive to load variations.

 

Adding more microgeneration with only such a relatively small "virtual spinning reserve" is going to create a lot of problems at peak renewable generation times.  There's the added problem that the micro-grid may well not be adequately frequency stable as it need to be for a normal grid tie inverter to lock in.  I doubt this relative lack of frequency stability matters at all for a micro-grid like this, so they just live with it.

 

What they need is to get Elon Musk to get interested in giving them a big storage system - that should fix the problem and allow a far more stable micro-grid frequency and allow the incorporation of local microgeneration.

 

In the meantime, having two systems in a new build is easy to do and makes sense, given the relatively low 5 kW maximum load per house.   

Edited January 14, 2018 by JSHarris

[ProDave]

I did some work on the Alladale estate, several miles down a private track at the end of an already long single track road. It was off grid and generated it's power from a small hydro plant.  You could see the intensity of the light bulbs going up and down and measure the rise and fall if the voltage. I expect the frequency was going up and down as well.

 

If you are wanting an electrician and it's in the summer I may be up for a few days on the island

[Onoff]

Welcome.

 

I see lots of talk of battery storage as a possibility. There's another thread just started here ref Sunamp by @AndyT of Sunamp. Let's face it a Sunamp is the place to store it!

 

 

Reading @JSHarris's comments as to what's inside the unit I wonder if you could power the heating element off of PV only (and maybe even wind?) whilst keeping the control side on grid?

 

Me just thinking out loud!

Edited January 14, 2018 by Onoff
Added the word "only"

[Jeremy Harris]

4 minutes ago, Onoff said:

Welcome.

 

I see lots of talk of battery storage as a possibility. There's another thread just started here ref Sunamp by @AndyT of Sunamp. Let's face it a Sunamp is the place to store it!

 

 

Reading @JSHarris's comments as to what's inside the unit I wonder if you could power the heating element off of PV (and maybe even wind?) whilst keeping the control side on grid?

 

Me just thinking out loud!

 

The Sunamp PV control system power is separate, as the unit has  4 core cable, with two line connections, one connected to the grid to run the control system and one the switched line from the PV system.  I agree, hot water from a Sunamp would make a lot of sense, the issue is how to provide a winter back up.  There will be around 30% of the year when the Sunamp won't be able to meet the hot water needs, and with only very limited "grid" power it's unlikely that a system to charge it from the grid when there hasn't been sun for a few days is going to work.

 

A Sunamp PV would charge from wind as easily as from PV, as all it does is detect whether there is power on the switched line and then start the charge process.  It would need regulating, as I don't know the limits for the Sunamp switched line input, but suspect it expects to see close to the same voltage and frequency as the main grid supply.

 

Perhaps an LPG multipoint might be an option as a boost heater after the Sunamp PV to make up for the shortfall in winter?  Depends whether cylinders of LPG are available on the island and the cost, but I doubt much gas would be used over the course of a year.

[SteamyTea]

Welcome

First thing you need to know when going just about off grid is what your energy and power requirements are.

So you need to break them down into categories i.e. Space Heating, Hot Water, Cooking, Lighting, Clothes Washing, Vacuuming, etc.

Then look at the maximum power needed i.e. 100W for lighting, 3kW for water heating, 4 kW for cooking.

Then the total energy required for each over a 24 hour period.

Add in some contingency and you should be able to work out the storage needed.

 

It is harder to reliably calculate the generation from wind and solar, but that is what the storage contingency is for.

 

Or just get a generator and a relatively small battery storage system.

[Jeremy Harris]

37 minutes ago, SteamyTea said:

Or just get a generator and a relatively small battery storage system.

 

The island already has that.  Currently the micro-grid that supplies all the properties has 112 kWp of hydro capacity, just under 10 kWp of PV capacity 24 kWp of wind generation capacity plus a diesel generator and a battery back-up system and inverter.

 

Given that baseload electricity can be provided by a pretty high percentage renewable scheme, I would concentrate any secondary microgeneration on site at peak shaving, rather than base load provision.  Hot water is an obvious first priority, as it's very easy to store heat, with none of the cycle life problems that electric batteries have.  After that it starts to get tricky to reduce loads.  Heat storage for heating is unlikely to make sense, as the very time when you need heat will be the time when there's little in the way of renewable generation. 

 

Combined heat and power might be a winter option worth looking at.  The same friend who makes his own biodiesel for his Landrover has been running his house off-grid for many years, with pretty much all his winter demand coming from a home made combined heat and power system.  He uses a big single cylinder Lister generator, with a heat exchanger on the buried in the ground oil drum exhaust silencer and runs his radiators from the waste heat from the engine and exhaust cooling system.  He runs the Lister on waste vegetable oil he gets for free, by just filtering it and pre-heating it to make it thin enough to flow through the engine injector OK. 

 

There are better CHP solutions around, now, though, including small Stirling engine versions.

 

I'm not 100% convinced that I'd look at battery storage just yet, primarily as the choice is limited and it would be an expensive investment.  Opt for an off-the-shelf system like a Tesla Power wall or a Power vault, and it's not going to integrate easily, because both really need a grid tie, and have to be frigged with to work as stand alone systems.  Opt for a more conventional off grid system, with something like Rolls lead acid batteries and an inverter/charger system and you're well and truly into DIY, with a fair bit of maintenance work, too.

 

I think my starting point would be to make the house so efficient that the heating demand is tiny (a bit like ours), and then you should be able to manage everything except hot water from the 5 kW microgrid supply.  The big demand is hot water, it will dominate energy usage usually, and there I think it gets to be a tough call as to whether to go for solar thermal or PV.  Normally it's a no-brainer to go for PV, because it's a heck of a lot cheaper to buy and install, plus you can export any excess generation.  In this case I don't think that may apply, as being able to store a LOT of hot water may well be a really big advantage.

 

One option not mentioned yet would be to forget about the Sunamp PV altogether, as I don't think it's the right product for this application, and look at fitting a large evacuated tube solar thermal array plus either a very big water filled thermal store, or better, if the budget allows, a Sunamp Stack, which would be a lot smaller and have a lot lower heat losses, allowing more hot water storage.  As a backup, then a low capacity inline electrical heater, that could be run off the microgrid during low demand periods, might do the job.  I think I'd aim to try and store maybe three days worth of hot water, if possible (that's a guess - I've not looked at the insolation data for Eigg yet!).

 

[TerryE]

The 5kW limit is quite workable for a new build if you are willing either to do manual scheduling or some from of home automation scheduling of high load devices.  Most kettles peak at around 3kW, so a kettle + a cold fill washing machine at the same time will be enough to "punish" you by tripping the 5kW breaker.  So some things are obvious: hot+cold fill for your washing machine, dishwasher, etc.  LPG for cooking.  But the main challenge is how to get the bulk kWh for your space and DHW heating.  Bulk LPG is a no-no, I guess.  And there is almost no coppice supply for renewal timber stove heating.  Clearly as others have said, a near zero energy build will make a big difference on the demand side, but you will still need to have 10s kW input per day for space and water heating.  And you will need an economic source for this, especially given the 3 km rough track access.   There are ~50 other households on the island and these must include some good working examples.

 

We have an MBC warm slab (search the forum; there are lots of debates about the advantages of this technique), but this includes ~10tonne of concrete inside the thermal envelope of the house which acts as a thermal store. 

 

Have you explored some like a rocket mass heater (RMH) option?  RMH systems often use cob rather than concrete as the thermal mass, and cob would be a more practical material in your case so long you are not relying on structural characteristics.  I have seen example (but I can't remember where, sorry) where someone effectively put a keel in their floor slab (surrounded by EPS) and heated this with an RMH to around 30°C.   By having one UFH "zone" running through the keel, this heat could be redistributed on demand to the rest of the slab, allowing the short burn RMH to provide a day-round steady space heating supply as well as working as a DHW pre-heat.  Sorry, as this is a really a Boffin's Corner topic and not something to consider lightly, but what I am saying is that there are energy-efficient options that you could consider.  @JSHarris, @SteamyTea et al, perhaps if you want to discuss this point, then we should move this discussion to the BC sub-forum as @tilpol has enough to consider at the moment.

[TerryE]

As a PS, I see that your total wall profile is ~300mm.  If you want an energy efficient TF then you are really looking at a total of 400mm minimum and probably 50 -100 more than that.

[AndyT]

10 hours ago, Onoff said:

Welcome.

 

I see lots of talk of battery storage as a possibility. There's another thread just started here ref Sunamp by @AndyT of Sunamp. Let's face it a Sunamp is the place to store it!

 

 

Reading @JSHarris's comments as to what's inside the unit I wonder if you could power the heating element off of PV only (and maybe even wind?) whilst keeping the control side on grid?

 

Me just thinking out loud!

 

Ok, just to keep you in the loop, we have been developing a new "Dual Port" cell.

I can't tell you everything yet (tease) but suffice to say you will be excited.  ETD end Q1.

 

 

 

[Onoff]

7 minutes ago, AndyT said:

 

Ok, just to keep you in the loop, we have been developing a new "Dual Port" cell.

I can't tell you everything yet (tease) but suffice to say you will be excited.  ETD end Q1.

 

 

 

 

What a wonderful place this is that people will genuinely be excited by this news!

[Onoff]

1 hour ago, AndyT said:

 

Ok, just to keep you in the loop, we have been developing a new "Dual Port" cell.

I can't tell you everything yet (tease) but suffice to say you will be excited.  ETD end Q1.

 

 

 

 

 

Old news here if it's this one!