RPC Staff Home Power Systems

Leading By Example

Most members of staff have a renewable energy system at home. Some are off-grid, combining solar and hydro for their energy needs. Others live closer to town and feed excess electricity to the grid.

Solar is for Everyone!

We all have different financial abilities, desires and priorities. For the two billion people in the world without grid power, a couple of electric lights would be an amazing luxury.

To a large extent, anything can be powered by solar. It is a question of money and relative affordability. By the same token, some people struggle to pay a basic grid power electricity bill of $250 per quarter - for others, paying $800 a quarter to power their air con and swimming pool is acceptable. We sell solar systems from $500 to $100,000!

A 'medium size' off grid solar system of 1500 Watts runs a widescreen LCD television, satellite dish, a DVD/VCR 5:1 surround music system, computer, breadmaker, toaster, coffeemaker, microwave oven, vacuum cleaner, washing machine, fans, 420 litre Electrolux fridge, blender, power tools and lights!

However, you would need a larger system to run an air con, an electric oven, 800 litre fridge, or to have a 56" Plasma TV on all day!

Dave Lambert's Grid-Feed System

Dave's new energy efficient home.

In February 2006 Dave made the move out of the bush and into the suburbs of Nimbin. He bought a 6yo three bedroom brick veneer house and now walks to work.

The house has a reasonable 'solar' design. It faces north and in the winter, sun streams into the eastern glass door at 7:00am and begins to warn the house. Some sun also enters the northern windows during the winter. During our hot summers, little sun enters the house. Being brick construction with slab floors means that it has good thermal properties.

The house has a lot of glass windows and doors – about 25 sq metres in all! In summer the southern and northern doors can be opened to allow a nice breeze to cool down the house on a hot summer day.

All the windows (except the back glass door) have thick lined ceiling to floor curtains. This helps to keep the heat out in the summer and in during the winter (once it has heated up during the day).

During the past 530 days I used an average of 4.06kWh/day for off peak hot water heating and 4.47kWh/day for general power. The off peak daily cost was AUD $0.22 plus .04 (access fee) and the peak power daily cost was $0.73 plus .40 (access fee). So the daily total comes to 8.53kWh costing about $1.39.

While Dave lived alone for over half this period, he feels his power consumption is quite reasonable. It is an ‘all electric' house with no gas or wood used for cooking or heating.

When Dave moved in he replaced all the lights with energy efficient compact fluoros. Dave said “I'm amazed how even a 5W fluoro is plenty bright for small areas, like the toilet, hallway and laundry room and as a background television light. I use 15 – 18W in the larger rooms such as the kitchen”.

Dave often raises eyebrows among his colleagues when he tells them he has a large reverse cycle air conditioner. However, during the two colder winter months, this is the most efficient method to heat a house – some 2.8 times more efficient than a bar heater. "I only use it for 15 – 30 minutes a day. I close off the two spares bedrooms and it heats the house in an incredibly short period of time. Similarly in summer a 30 minute cold blast will remove that sultry sticky summer heat you sometimes get in December and January".

During July 2007 Dave made some further changes to increase his energy efficiency. He purchased a heavy curtain for $100 for the northern sliding glass door and spent $750 to have the ceiling insulated with R3 glass wool batts. Dave said “The difference was noticeable on those cold nights – the house stayed comfortably warm until I went to bed. I'm told that it will make the house 6 – 7C cooler in the summer. This means I'll use the air con even less and my fridge won't work as hard in summer. I decided to insulate the ceiling now even though I understand there is a $300 NSW government rebate for insulation commencing in September 2007”.

The other big change is that Dave had a 1.04kW grid feed solar array fitted to his roof. The super efficient Latronics inverter starts exporting power to the grid at 7am even in July! Dave expects to generate about 4.8kWh/day from his array which will completely offset his peak power!

In fact, he should even become a net daytime exporter now that his ceiling is insulated. Dave commented “I'm thrilled to become carbon neutral at last for my peak power”.

Dave has a few more plans up his sleeve in coming months. The western wall gets very warm during the hot summer months as the sun begins to set. Dave intends to invest in a $100 cream coloured shade cloth (which will match his bricks). This will block out about 90% of the sun over a 9 x 2 metre area. The final plan is to acquire a solar hot water system after 1 January 08 at which time he has heard the NSW government will be offering a $1,200 rebate.

Dave said “By early 2008 I expect to become 100% carbon neutral which is a fantastic feeling”.

DC's Bush Cabin

Carport with House

Dave has worked for the Rainbow Power Company since its inception in 1985. He is commonly referred to as DC, which is not a bad handle to have in this industry.

Dave's system consists of 14 x 52W Photowatt double glass solar modules. These modules charge a 24V 438Ah Trojan battery bank, controlled by a Plasmatronics PL40 regulator. All lights are 24V, either Halogen or fluoro. A Selectronic SA21 Inverter, rated at 1600W on 24 volts, supplies the 240 Volt AC for the house.

Dave also uses a Jaycar 8A continuous switchmode power supply to provide power to run his UHF & VHF two-way radios. He also recharges his mobile phone with this unit.

His fridge is an Australian made Autofridge running directly of the 24V supply. Dave reckons this fridge is awesome. The fridge turns on when the base temperature is 1.6 deg C and stops when the temp is O.9 degrees C. This will keep milk for one week. "It's fantastic" says Dave, "and because it's built so strong I can also take it with me when I go camping in my 4WD Hi-Lux."

The Selectronic inverter is usually loafing running a 63cm TV, a Panasonic DVD player and a JVC video. The washing machine is a 5.5Kg Fischer & Paykel and has run faultlessly for over 6 years. The only time his inverter really works is when he runs his 1600W vacuum cleaner. Dave only uses the vacuum when there is full sun on his panels. By using it this way half the power comes directly from the sun whilst the batteries supply the rest. The only other 240Vac loads are a 1000W toaster, a 300mm pedestal fan for those long hot Nimbin nights and an assortment of power tools for building and furniture renovation.

Previous to this system, Dave ran with a 12V system using three solar panels with a combined wattage of 190 Watts and a second hand set of wet cell Ni-Cads of 139Ah capacity. He used a gas fridge in this set up but still managed to run his washing machine. This system was used for over ten years. Before that Dave used one 42W Solarex panel charging a second hand set of 90Ah ex Telecom batteries, with just a few lights and a black & white 12V TV. Dave has lived on solar now since 1984.

DC's village home

In September 2009 Dave decided it was time to move into the village. He purchased a house with a large north facing, unshaded roof and took advantage of the government's 60c/kWh solar bonus scheme.

He had RPC install 20 x Trina 185W (3700W) panels, in two strings of ten, and a SMA 3.8kW grid tie inverter.

"The two install guys started at nine; the level 2 sparky arrived at midday; by one thirty the system was putting power into the grid, I'm really happy with it" said Dave.

The system has produced as much as 22.3 kWh on a good day.

The house also has a Solar hot water system but for some strange reason the previous owner put it on the western roof! It may get moved.

The house also has R5 insulation in the roof space.

John's Energy Farm

When the Solar Bonus Scheme was announced in 2008, John started planning a large solar system to take advantage of the government's generous scheme and to secure power supply in the long term.

The system is made up of 4 solar trackers with 12 x 185 Trina solar cells on each. An SMA TL10000 inverter does the electronic work. The use of SMA equipment means that the setup could be integrated into an independent battery based system if there are ever any problems with power supply in the future.

Each tracker is controlled by its own electronic box that is powered by a small 5 Watt solar panel mounted at the front of each array. The electronics in the control box uses the output of the small panel to determine the best angle to start and end the day's tracking and then works out the best time frame under which to complete the arc.

The system's effective production meant the local grid provider (Essential Energy) needed to upgrade its infrastructure to cope with the high current flowing back into the grid. Essential Energy came through with a line upgrade (and paid for it, too) and all is now well.

The best result achieved regarding power output has been 84 kWh over a day. This is a great result for a system with a nominal capacity of 8.88 kW. John says the tracking adds around 30% to the power output on a sunny day but has little effect on cloudy days.

Terry Thomas' Home Power System

Gone Bush

Terry has lived with solar power for nearly 20 years. He first started off visiting his caravan once a month, charging his battery up in his vehicle.

He purchased his first solar panel from RPC in 1986, but it was destroyed 2 weeks later by cricket ball sized hailstones. Undeterred, Terry now has 16 x 80w panels but has made sure his insurance company knows they are included in his house insurance. Fortunately, no such freak event has occurred since.

The panels charge a 500A/h Trojan battery bank - soon to be upgraded to 1000A/h since, currently 20% of the battery capacity is used each night - which will be reduced to 10% with the larger battery bank.

During wet weather a small RPC hydro backs up the solar panels. However, a generator & battery charger system has had to be introduced due to the increasing prevalence of drier weather.

Terry has had a 220L 12-volt fridge running faultlessly for 12 years run by a 30amp 24v to 12v down converter. This also runs his 12v stereo & 12v two pin power points for such small things as torch charger, CB radio, mobile phone charger etc. This is most convenient if the inverter is off due to long periods of cloudy weather. Otherwise the inverter stays on all the time for video clock recordings etc.

The phone & answering machine are run separately off an unearthed 100A/h gel cell battery for lightning protection. It has its own solar panel.

Terry is able to run all modern conveniences with a 1200w Selectronic Sine Wave Inverter, including a 59cm TV, video & digital box, 800w toaster, 1000w vacuum cleaner, 6kg washing machine, a 1200w spa pump , 240v 40w fluoros in the garage & laundry & all power tools - not all at once of course.

A Plasmatronics PL40 regulator is used to monitor & record the volts, amps & amphours history of the system & boost the batteries.

Cooking is done with gas or combustion fire. The hot water is heated with a stainless steel 300L Edwards Solar Hot Water System, backed up by the combustion fire whilst heating the house in cold or wet weather.

An efficient solid fuel electric generator is on the wish list.

Marco's Home Power System*

Size does matter

*Marco has since sold his home, but his story remains relevant for many newcomers to solar.

Started out with 8 x 83W solar panels and too many "necessities". The latter were trimmed back or changed so that instead of running a desktop computer all day, a laptop was used instead. My first experiences with solar power were interesting and, in hindsight, amusing.

Solar power systems are not like mains – you can run out and you need to be conscious of what you're running and when you’re using it. Living on a solar power system also makes you more aware of just how much we take for granted and how reliant most of us are on plentiful supply – solar power makes us much more involved in the whole process: anyone on a solar power system needs to know their system to some degree. This doesn't need to be too involved, but you can't just sit back and consume.

I believed many of the myths and misconceptions about what solar power systems can and can’t do from well-meaning griddies (folks on the grid) and for a year or so I tore out my share of hair. For instance "computers use negligible power", "you can't run washing machines off solar power". After talking to Dave at RPC I bought a few more solar panels (4 x 120W Kyocera solar panels) and upgraded a few other things, and most importantly, I started to take a real interest in the solar system and how best to look after it.

Haven't looked back since – the solar system is charging along, the poor generator is feeling rejected, and Mernisa and I haven't had to make painful compromises. There are more additions planned in the future (e.g. 12/24V fridge) but for the moment everything is going just fine. Solar power is important to me from a philosophical point of view as well as financial one: I don't miss power bills or black-outs!