Ayres Rocks

I haven’t had time to scratch the proverbial let alone sit and write about what has been happening so far.

This update will be quick fire since we did not do much of the work ourselves. At the start of October we measured up the build area and set out the cut for the house and the areas for the topsoil and subsoil spoil. Around October 8th our neighbour started on the earthworks for the building site, cutting as much of the site as he could.

What he did find was an enormous lump of rock and several smaller ones that prevented him making a clean and full cut to the site. We have some photos of the cut area up on the flickr account here. The rock is huge but the camera doesn’t distinguish it well from the soil in the background, but trust us as we walked around it and lamented its being, it is massive.

That rock has since been removed and we will get up there and get some more photos of the finished cut this weekend, weather permitting. As I mentioned, only a quickfire update but stay tuned – the plumber and concreter are communicating between themselves and it looks like we’ll have a slab ready to build on in about 4 weeks.

Wise Drafting for the building consent drawings and required revisions for certification $860
Footersville for truss and frame engineering $160
Officeworks for photocopying and printing of plans $112
Pocius and Associates for the certification of the application $720
Council fee for lodgement of documents $52

House only spend now stands at $225 154.90

In the mail today was the official council stamped copies of our development application along with a little letter culminating in the words “APPROVED”.

Yay! Now the easy bit is over with it’s time to get on with the preliminary planning and coordination of the excavations, concreting and under slab plumbing.

I can hardly believe it myself. I picked up the completed certification documents from Tany at Pocius and Associates yesterday morning and drove straight out to Cambrai to lodge them with the building consents officers at the council.

The officer explained how the process unfolds from here, and it is simply they check the planning approval against the final plans to make sure we are not completely turning the design on its head. By law they have 5 days now to stamp the documents with the big “approved” stamp and return them to us.

To get to here we have needed help from some really dedicated people and would like to issue thanks to the following:
Aaron, one of the council planners who has always been quick to provide (or find) information when I ask for it whether it was in his department or not. Council need more dedicated people like Aaron.
Darren from Wise Drafting for his great ideas and input early on in the ideas to plans phase.
David and Glenn from RCI Engineering for their quick turn around on the engineering work.
Daniel and Jason at Footersville for quickly supplying all the engineering for the roof framing.
David and Lee from BlueScope Lysaght for the quickest ever quote for steel roofing materials.
Our parents/inlaws for listening to all the ideas and helping give outside perspective. Sometimes you can bury yourself so far into an idea it’s hard to see flaws in your thinking.
And finally to Tany from Pocius and Associates for putting all the bits and pieces together and making sense of it all for us.

From here it’s now time to drag out all of those sketch books and note pads and get all of the ideas and drawings collected over the last 14 months into order so when we have that actual final piece of paper approving the build we can swing it all into action.

Dare I say it, but after a quick email salvo back and forth between us and the certifier it looks like we will have the approved documents in our hands this week. While this should give us a free pass through council I’ll not take that for granted seeing as this has taken so long with so much reworking of reports to get to this stage.

A huge thank you to Tany at Pocius and Associates for getting all the paperwork sorted and the checking through and certifying of all the engineering documents.

I got myself a heavy combination (HC) truck license as well for future use as we develop our business plan on the block. If you are looking for a truck license in Adelaide I can highly recommend Rob and the team at GNL Heavy Vehicle Driving Centre. I had a great time learning how to drive the Eaton Road Ranger gearbox and with Rob’s patience and excellent tuition I soon felt very comfortable with driving such a large vehicle.

The certification process
First volley back from the private certifier gave me a list of 13 items that needed more clarification, validation or that were just wrong. I’ve just resubmitted the revised items and we are confident we now have all the pieces of the puzzle, it’s just we need to fit it altogether.

The certifier is being very thorough and that is exactly what we are paying him to be. I’m still amazed that this far into the journey, with all we have learnt, we could still have so much that needed to be tweaked. If we were to do this again I would retain the certifier from the start as the length of this process is in chasing everyone else for the corrections to the work that have done for us.

The self sufficiency quest
I have enough data now to know just what conditions we will be facing in terms of getting power generated. Using that data and manufacturers’ specifications I now know we will need a single 2kW turbine backed up with 1kW of solar panels. This really does not change the overall costs of setting all this up it just better spreads the opportunity to make power.

Ironically what I have seen from the data collected is there are days with not enough wind and not enough sun to produce enough power. However these are roughly 1:100 day events so they are isolated, though it seems these days are the calm before the barometer swings heralding the changing of weather patterns. Our intended battery backup will provide ample power for these odd days.

Planning the build
Having the confidence now that we are on the right track and approval is going to be sooner rather than later I’ve spent a lot of hours working out just what it is I need to manufacture to be able to make the mould system to build the house. Using graph paper to map out the block outline of the house I have been able to work out how we are going to stage the build and what mould components will be needed for each.

Essentially I have tweaked the sections to be built so were have the maximum use from an absolute minimum pool of parts. Less parts of course makes the system cheaper and quicker to build and leaves us with less to transport or store.

Testing the theory
Every council has guidelines allowing you to build an outbuilding of certain size without needing to seek planning or development permission and in our council this building size is 15 square metres. We will build a shed of this size that will later become the storage area for the self sufficient power components. The roof of this shed will become the base for the solar panel array so the shed will be orientated to make maximum use of solar north so the panels we have will be generating the maximum power a fixed array can.

The shed will be built on strip footings with a floating concrete raft as a floor. I’ve used the engineering specs from the house to specify the footing depth and width and also the lintel details for the window and door. Since this is a trial run, we’ll be using exactly the same principles and design spec to make this shed so it will be perfect opportunity to test ALL of the components of the house. The roof will also provide enough rain to supply a 5000 litre tank while the shed itself will be a perfect storage area to keep us and tools out of the weather.

This building we will start on as soon as we have the building consent for the house.

As it turns out I found errors in the paperwork while duplicating it all so we did not actually get the completed documents to the certifier until early mid July. I’m sure it won’t be a great shock for you all to read that it’s taking a lot of work between the certifier, draftsman and engineers to get a cohesive set of paperwork ready for the building approvals. A lot of this is due to new rules and regulations being introduced in July and the plans needing these changes reflected where the old codes and regulations were quoted.

However we have a super motivating deadline to make or we will well and truly be knee deep in “it”. September 1 brings in a raft of new energy efficiency mandates for new buildings. While our earth based structure cannot be rated and is deemed simply to “comply” we’re having enough fun and games now defining just how it does comply to satisfy the SA housing code.

On the spending front we’re been very quiet with nothing specifically purchased for the house project. I’ve also decided to go back through the costing posts I’ve made and only include costs specifically for the house. We’ve registered a business name so the property is now officially an income producing entity and a lot of the previous costs were input into that business and not really at all to do with the house.

I’m really looking forward to that post that lets you know we have the green light to go ahead and build the damn house. Fingers crossed it’s no more than 2 weeks away.

With some data of our power use patterns collected over the past 2 weeks I’ve crunched some figures and did some more research now that I have a better idea of what our peak power load is likely to be. For starters I’ve upped the main power system specs from 12 volts to 24 volts. This will allow a much larger capacity 1660Ah battery bank and that alone should give us autonomous power for 36 hours should no wind blow.

Switching to 24 volts will also allow a larger inverter of 4kW, and upgrading to this larger inverter means we can run the lights off the same system, rather than installing a turbine and batteries just to run lights. The changes to specifications surprisingly have added very little to the system cost, and by shopping around online I have brought the components for the entire system, using recognised brand names, down under the cost of mains connection. More importantly the components I have selected can be added to in series meaning the capacity of the system can be increased simply by wiring in the additions rather than replacing critical components.

The Bureau of Meteorology website has a great range of historical statistical data which I have been compiling for 18 months or so for the region we are building in. 36 hours with no wind of sufficient strength is as likely to happen as the sun not coming up tomorrow. It’s extremely rare for there to be more than 6 hours of less than 10kmh winds over any 24 hour period. No sufficiently strong wind for 24 hours has never happened.

All I need to do now is take all the data to someone I found locally who specialises in wind and have him re crunch the numbers I have to confirm it will all do as expected.

At the back of my mind for the past few months has been the niggling doubt over connecting to mains power. We do have a 19Kv line running through the property, with a power pole approximately 140 metres from where the house is to be sited. So the cost involved to get power to the house is “affordable” while still being a fair whack of cash. For arguments sake lets round the figure to $20k for the transformer and then undergrounding some enormous cables from the pole to the house, all grunt labour supplied by myself of course.

Water pumps
Being dependent on rain water means we also need to pressurise the delivery of it. One option here is to use a header tank and that will do away with the two 400W (400 watts) pressure pumps we would have needed. 800W of power using pumps may not sound like a big power draw, but I’ll explain later on why we are better off not having them if we intend being off grid for power.

Lighting
I spent some time yesterday looking at the quickly evolving LED “globe” technology which is a major advance in lighting efficiency similar to the step from incandescents to compact flourescents. Doing the sums on our proposed lighting for the house we would need to run about 1000W worth of these and this we can do over a 12 volt network rather than conventional 240 volt.

I’ve done some preliminary costings on a small 200W 12 volt turbine and 4 deep cycle SLA batteries at under $1k to forever eliminate the power bills for lighting. My scrap paper calculations reckon on this setup being able to power lights for 3 days (typical use) should no wind blow. With the average windspeed we have the system should be able to power entirely off the turbine with the batteries there for backup on the very rare occasion it is calm or when the turbine needs to be taken out of service for maintenance.

Appliances
Since we’ll be using gas to cook, wood to heat and solar for hot water –  the 3 largest users of electricity in electric only houses – I crunched a few figures on exactly what we would need to produce and store in terms of renewable energy to power the house. 

We have the typical “always on” items such as fridge and chest freezer. Then we have the usual appliances that are used in short bursts each day such as the kettle, toaster, microwave and tv. We are now keeping a logbook of the usage of each of these short burst use appliances to see just how much power they are likely to use.

The limitations
It is very important that one thing is kept in mind here, and that is the PEAK POWER LOAD. One thing about being off grid is you are limited in the amount of power you can draw at one time. All of these systems run inverters that take DC power (directly from the turbines or the battery banks) and turn it into 240 volt AC for use inside the house.

Typically a 3kW (3000 watts) 12 volt  inverter will cost $2800 and will let you draw up to 6kW for 1-2 minutes at a time. If we were to consistently exceed 3kW of power draw (done as simply as having the  kettle and toaster running together) we would need to add another expensive inverter to share the load. Constantly abusing the inverter by exceeding the rated power will of course shorten its working life.

By simply using the kettle, then using the toaster we can avoid the above situation but it means being very aware of what we have running and when. Removing the water pumps as discussed above will also help keep down that peak power load. All these systems require a power dump when power excess to needs is generated and we’ll divert that to a pump to fill the header tank. The header tank will overflow back to the storage tanks so it can pump away all day if it needs to.

Wind versus solar
Dollar for dollar wind will deliver more power and by a large margin. Considering the wind blows 24/7 and the sun gives 10-12 useful hours a day for solar energy that fact should be a no brainer. A 1kW turbine will set you back less than $5 000 where a solar array of the same capacity would cost you $14 000. The turbine of course is useable 24 hours a day and the solar array only half of that.

In terms of storage the turbines always being capable of delivering power means we need a much smaller storage solution. A 12 volt battery bank can set you back $3 000 for a low draw scenario such as wind power then go all the way up to $22 000 for high draw capacity as needed for solar.

Calculating what we need
Unfortunately the renewable energy market is focused on city based installations and of course they are only interested in solar installs. Similarly government rebates in the past have been heavily focused on solar since most of our population by default lives in densely populated areas. This means finding any sort of online calculator to work out the specs for a system has proved impossible so far.

Piecing together information has led me to believe we can get a wind powered off grid setup consisting of:

• a small battery bank,
• three 1kW turbines (1 spare for redundancy in case of breakdown, maintenance or future expansion),
• three charge controllers to send power to the batteries,
• an inverter to deliver the 240 volts required to the house
• a small diesel generator for battery conditioning and power top up should it be needed
• a dedicated shed for storage of chargers, inverter and batteries.
• a seperate 12 volt system for lighting only

for under $25 000. While this initially is more expensive than connecting to the grid, that $5000 gap should be recouped within 5 years at todays power prices.

And about time too. I’ll need to spend just about a full day this week duplicating all the engineering specs for the final council applications, then it’s off to the certifier to get all this privately approved before we send it off to council for the rubber stamp of approval.