Sunday, 8 November 2009

Installation of Remote Power Supply Nearing Completion

Ochre Arch has never been grid-connected to mains power. That's right ... we have until this point managed to survive quite OK without electricity on-tap. Here are some of the most commonly asked questions we get on this subject, together with our stock-standard answers:

How do you cook and keep things cool?
Initially we relied on our gas barbecue and camp twin gas burner for cooking. For cooling foods and drinks we used Phillip's parent's small camp chest cooler; and for larger gatherings we'd buy ice in town and use this in an old small refrigerator that has the motor removed ... with us lying it on its back and using is as a chest cooler. In recent times we have up-graded to a gas stove and gas refrigerator. Toast is made on a camp toaster.

How do you get on with washing clothes?
We do have an 8 KVa petrol generator that we have used to power the washing machine, but in the main we use the laundromat in Grenfell.

What about showering?
This is where the Tardis (outdoor shower) comes in handy during the warmer months. (Refer to an earlier blog post). We now use a 12 volt battery powered camp shower in the shower recess. Water is heated in a boiler on the wood heater during the winter and stove during the intermediate months, and in a black 60 litre plastic garbage bin via sunlight during the summer months.

What about lights at night?
We have small garden solar powered lights around the yard. As a general rule we use gas lights in the house, but have also used candles from time to time. We also tend to be more attuned to the rise and fall of the sun than before ... now waking at what we used to call 'sparrows' and going to bed much earlier.

What don't you do that you used to when you had power (prior to moving to Ochre Arch)?
Ironing of clothes is no more, or hair drying. Jan does miss her electric food processing appliances. There is NO TELEVISION here at all, which to be truthful we've not missed in the slightest ... to the extent that we find the number of ads when we do visit others and see a bit of television incredibly annoying. We do like our movies and do miss kicking back and watching a good DVD on rainy days.

So will you be feeding power back into the grid once you have your remote power system in place?
We don't really understand why, but it seems most people need us to tell them 2 to 4 times that we are not on mains power or grid connected before the penny drops that we are, in fact, not on mains power or grid connected. Thus we will NOT be feeding power into the grid after our remote power system is fully operational. The nearest mains power pole is about 1.6 km away.

Setting up a remote power supply system is FUNDAMENTALLY different to having solar panels in place and feeding into the grid for at least 3 key reasons:
1. Power has to be stored on site - in batteries
2. Unless one has an unlimited budget it is essential (for serious and reliable power use) to include a back-up non-renewable energy generator into the overall set-up
3. There is no opportunity to reimburse costs (from grid-connecting).

Have you been able to access any Government funding for your remote power system?
Yes. Until recently the Federal Government provided a 50 % subsidy up to $250,000 for the renewable energy components of remote power supply systems where the following conditions were met:
1. The location was / is the principal place of residence.
2. Mains power was at least 1 km away
3. A quote had been given showing that it would cost at least $30,000 to have mains power connected.
We met all 3 criteria.

How do you manage to run a computer?
Quite a while ago we bought a 60 watt soler panel with a regulator specifically designed to charge (and not overcharge) 12 volt batteries. We have two car batteries that we rotate on the regulator ... one charging while the other is being used. This does involve manual transport of the batteries from near the car shed to the house, but in the scheme of things the set-up works well. We also have a small 300 watt inverter that runs off a 12 volt battery, which we use for charging things like mobile phones, digital camera etc.

The rest of this blog shares some bits and pieces of information and photographs on the remote power system we have almost completed. The two main activities yet to be completed are installation of the diesel back-up generator and wiring of the house and sheds (machinery and shearing).

The first major steps in setting up our remote power system were:
1. Finding a supplier / installer. We opted for Central West Solar in Orange. Robert Biviano has proven to be not only extremely knowledgeable and capable, but also great to deal with.
2. Ascertaining the system capability and design components.
3. Building a shed which has become the 'centre' for the power system.

This photo shows the shed, taken at the time the batteries were being delivered. Our need to build a shed was driven by:
1. Limited storage space on the farm to begin with
2. None of the existing buildings had north facing roof areas large enough for what we needed
3. We did not want the panels to be mounted at ground level as they would in our view be more likely to be damaged through stock and unforeseen events and they would also be easier to steal.

There are 15 X 175 watt panels in all, set up as 5 'strings' of 3 panels. In this photo you can see Robert Biviano putting the final touches on wiring each of the 5 strings into the small box (a fuse for each string) from where the central cabling to the batteries takes place. The cables used at the back of each panel are fire resistant, however it would be naive to think that the shed and system would come through unscathed in the event of a major fire event.

When building the shed we took the needs of proper positioning of the solar panels into account. Specifically:
* Half of the roof faces north
* Two of the top-hat supports for the iron are 1500 mm apart, which allows for easy anchoring of the panels
* Underneath each of these supports we have inserted 35 mm X 35 mm cross section treated pine to allow for very solid anchoring of the screws.

As a rule of thumb the angle of the solar panels in relation to the Earth's surface is 'latitude plus 10 degrees'.

For the remote power supply system to work it was necessary for us to run a range of cables under the soil surface:
1. From the house to the power control unit
2. From the power control unit to the shearing shed
3. From the power control unit to the base of the (new) wind turbine.
Rather than dig the trenches by hand we hired a trencher and driver for what turned out to be 6.5 hours. The trenches are by law to be 600 mm deep but given we are on a farm where digging for fence-lines and such like is not uncommon the main trench was dug down to just over 1 metre deep. The accompanying photo shows the Bobcat, with trencher attached, near the north east corner of the house.

We decided to incorporate a wind-turbine into our overall system for several reasons:
1. Our house is quite open to the elements and it is frequently windy here.
2. We really liked the idea that the wind turbine potentially runs 24/7, whilst the solar panels are restricted to daylight hours.
3. Inclusion adds another element for potential tourists to see when they visit.

The unit we purchased is rated at 350 watts, or twice that of each of the solar panels.

There are two types of typical tower construction, the Guyed tower and the Monopole tower. Ours is the former, and thus requires substantial footings to support each of the main guy support cables. As luck would have it the fellow who did the trenching for us also happened to have a 600 mm diameter auger that fitted to the Bobcat. This photo shows him digging to a depth of just over 1 metre one of the four holes for the footings.
The Owner's Manual for the Wind Turbine contains the following paragraph which I think is worth sharing: "The sun is the source of all energy on earth. Wind is a form of energy and is caused by the uneven heating of the earth's surface by the sun. For example, the poles receive less energy from the sun than the equator does, and the dry land heats up and cools down more quickly than the seas do. On much of the earth, wind speeds are low in the summer when the sun shines brightest and longest. The wind is strong in winter when less sunlight is available. Wind speeds are also low during the day when sunlight is strong, but increase after dark when the earth surface is cooler. Because the peak for wind flow and sunlight occur at different times of the day and year, wind energy and solar energy can compliment each other. A hybrid solar-wind power system can balance out the ever fluctuating solar and wind resources and is more likely to produce power when you need it".

When we designed our remote energy system we assumed NO energy would come into the system from the wind turbine as its reliability can be much less than with solar. Reading the above paragraph has been illuminating for us, and we feel that our decision to include a wind turbine augers well for the future of our power system. Based on the modelling done by Robert on a worst case basis, assuming peak power demand and low solar supply, during the month of June we might expect the generator to run for a total of 30 hours. It will take about one hour for the generator to re-charge the batteries when it does kick in.

This photo shows the cement mixer delivering approximately 1 cubic metre of concrete for the footing of the wind turbine / tower. There was some concrete left over and we used it to fill some of the holes in the concrete floor of the shearing shed.
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The blades of the turbine are approximately 1.8 metres in diameter. Here Jan is holding the blade assembly prior to it being affixed to the turbine itself.

I found it interesting that the turbine has the ability to stop turning in extreme conditions to prevent damage. It does this via an electromagnetic mechanism within the turbine; without any parts moving per se.

The design of the guyed tower is extremely ingenious. The concepts are simple, however I would not recommend anyone take on installing one like ours without first having seen one installed elsewhere. The tower is 13 metres tall. This photograph was taken immediately after the tower was in place. We all found it amazing that during the construction phase there was 'not a breath of wind' (perfect for what we were doing) but about 10 minutes later a heck of a breeze blew up. This allowed us to see how the turbine reacted and also to see via the control panel what the power output could get to (500 watts at that time).

Construction of the wind turbine did not finish until late in what was a long day. The wind gust gave us all a real sense of job satisfaction. This photo shows Robert and his team enjoying the experience. Those in the picture are from left to right: Damian (recently started with Robert as a 1st year apprentice. This was his first involvement in setting up a wind turbine), Sim (third year apprentice with Robert. Our remote power system was the first time Robert had put Sim in charge of an installation - under Robert's supervision when needed, of course), and Robert.

The observant readers will have noticed from the first photograph in this blog post that our new shed is basically 2 X 40' shipping containers with a (40') gap between them, all under a metal roof. Such a design was suggested to us by Jan's brother Tim. A bonus of using containers is that it is very easy to create rooms within each one. In our case we always intended having a room on the south to hold all of the controls and batteries for the power system. This photo shows the access point for the room ... accessible from inside the shed, with the door simply cut straight out of the side. We have more to do to ventilate it properly, but at this point in time 2 holes have been cut in the top of the container, over which we will install some whirly-bird vents. In the foreground you can see some of the trenching, ready for cabling to the shearing shed.

In the trench you can see is now two conduits: one for power to the shearing shed; and the other now containing telephone cabling. It is intended to install a modem in the control room which will allow for diagnostics to be carried out on the system via internet.

The battery bank is the 'heart and soul' of our remote power system. In all, there are 24 X 2 volt batteries creating a 48 volt storage system. Each battery weighs in excess of 65 kg, has no handle, and is difficult to handle. The (in excess of) 1500 kg of batteries store 1200 kilowatt hours of power. I think of this figure as basically sufficient to run 1,000 (1200 watt) vacuum cleaners for 1 hour. Here you can see some of the batteries being connected together. The batteries are 'gel' filled (rather than water) meaning they (should) last longer, require less maintenance and are less hazardous.

The technology involved in the overall system is substantial, and does require maintenance. We've a ways to go in getting up to speed with all the bits and pieces but do have an appreciation of the major components.

In this photograph you can see Robert preparing to install monitoring software on his laptop. Some of the batteries are visible in the lower right of the photo. On the wall, from left to right, is:
1. Inverter - converts the direct current (DC) from the batteries to alternating current (AC) making it in a form usable by various appliances. It also converts AC from the back-up generator to DC when supplemental battery recharging is appropriate.
2. Main cut-off switch and central wiring.
3. Wind turbine controller
4. Solar panel controller

The final photo shows the shed and system as it currently stands. The wind turbine is located immediately behind the shed, and is visible over the top of the shed if you look closely.

Some initial observations on the system at this point:
1. We think it will be 'just what we need' based on a whole bunch of factors
2. The wind turbine does make a 'whhissshhh' sound during strong winds. That said, this is offset by the noise of the wind in the trees near the house. The noise will not be a problem.
3. The tower does flex when the turbine is going. It is best that turbine be installed on their own towers rather than on fixed sheds etc. as the vibration can be noisy.
4. The controls do emit a low humming sound from cooling fans etc... not an issue at all for us given the distance of the shed from the house.

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