Living with Solar
Living with solar successfully requires being totally aware of the energy you use. Here’s a general guide to how to make it all work.
The key is to minimise energy usage first. You can often slash such usage by half – or even more. This requires you to pay for some changes. Doing this, however, and the cost of solar you need is hugely reduced.
Our first (home) all solar house north of Broome (WA), gave invaluable experience. It’s up to 17 kWh/day adequately coped with our under 8 kWh/day usage. Building and living with it for 10 years showed that feasible.
Our all-solar 10 acre property on the Indian Ocean north of Broome, Western Australia. Pic: solarbooks.com.au
Our major living with solar achievement, however relates to moving to Sydney. We bought a solidly-built and relatively new house overlooking Pittwater, that was 100% grid supplied. Planning to install solar, we found previous electricity draw was 31 kWh/day.
In this and similar situations, do nothing (solar-wise). We first tracked down and slashed that absurdly-high usage. An instant-boiling (and ice-cold) water unit was constantly ‘on’. While used only a few times a day, it drew over 5 kWh hours per day. Six heated towel rails used a total of 3 kW/h a day. The over 80 halogen light globes drew 50 watts each. A 20 year-old (and huge) fridge drew 7 kWh/day. Garden lighting was all incandescent and timed to run from dusk until dawn. Another 3 kWh each time.
That most extraordinary draw was a very old electric door bell. Despite being used only a few times a week (for a second or two each time) the 230 volt transformer system driving it drew a constant 50 watts (over 1 kWh/day). We replaced it by old-fashioned brass bell.
Within a month we slashed usage to 10 kWh/day, then to 7 kWh/day two months later. Doing so cost well under $5000. Had we not, the solar capacity to supply over 30 kW a day would have been non-affordable.
Only then did we install (grid-connect) solar. The initial 2.4 kW system cost about $14,000 less rebate. Usage in 2017 was about 7 kWh/day in winter, and 4 kWh/day in summer. We did, however retain gas heating. Solar input exceeded usage for much of the time. The power grid was used as a ‘virtual battery’. Electricity bills rarely exceed the fixed service charge.
In 2019, we decided to convert home heating from gas to reverse-cycle air-conditioning – using Daiken units. To power them we upped the solar array (from 2.4 kW) to 6.6 kW. Furthermore, to use that otherwise huge excess to charge a 14 kW/h Tesla battery. This system now produces from a typical mimimum 12-14 kWh a day to a more common 24-40 kW/day. We sell the considerable excess to the grid supplier for a current 20 cents per kW/h. The grid acts as a virtual battery back-up. It is rarely used.
Our elecrical power is now ultra-reliable. Even in the event of a long grid power outage we can readily cope.
How to slash usage – change usage habits
Turn off all appliances at their wall sockets, never by a remote control alone.
This particularly applies to anything made prior to 2014 that has a small power unit built into its plug. It applies also to many electrical appliances bought (or via eBay) from overseas. Unless turned off at the wall switch, each little power unit continues to draw power. Such power varies from a watt or so – to as high as 10 watts. This may seem trivial. On the contrary, however, an average home has 30 or so of these. At even 3 watts each, that’s over 2 kWh/day.
Do not leave lights on unnecessarily. Do not leave an unwatched TV with its sound turned down. Turn it off (at the wall!). Use less water when showering. In particular, buy only energy efficient appliances.
Do not use any instant boiling/cooling water system. Boiling water takes only a minute or two in an electric jug. Have a cooled jug of water in the fridge.
How to slash usage – items to change
If it’s made prior to2014, consider selling the existing fridge. Buy only one of high Energy Star rating. Never have two or more smaller fridges. Always have one just one that’s the same overall capacity. Why? It’s because one (say 750 litre fridge) draws about half the power of three (each of 250 litres) fridges.
Change all lighting to LED. This is readily done as LEDs are now made to fit existing fittings. Do not buy cheap LEDs. These produce less light per watt than the more costly ones. They also have much shorter life. In some areas, the electricity supplier may do this at no charge.
Living with solar – how much do I need
Right now, grid connect solar works best for those working from home. That which comes in during the day is used that day. Some install batteries to feed the home at night, but your are unlikely to gain financially. It can however act as a back-up during power outages.
Living with solar – maintenance
There virtually is none when living with solar. The solar modules may need occasional cleaning in some areas. This is particularly so after a long dusty outback summer. Dry winds cause static charges that attract dust. Brief light rain may not, however, wash it off. Often, light rain turns the dust into mud that subsequently dries hard.
Fix both the dust and static issues by washing the modules with water and detergent. Then rinse with a bucket of clean water to which you have added just one teaspoon of detergent (it has anti-static properties). Use a squeegy to remove surface water – and then let the modules dry naturally. Do not rinse further, nor wipe dry, let alone polish. Doing either/both generates dust-attracting static charges. Static build-up can be reduced by earthing the solar module metal frames.
Apart from the above, solar modules need no maintenance. It is difficult to assess their usable life-span, Some, however, made in the1980s still produce about 80% of their original output. Total failure is very rare.
Reliability when living with solar
A well designed and installed stand-alone system is usually more reliable than the grid network. Furthermore, output is cleaner, and voltage barely varies.
Energy monitoring – an essential
Energy monitoring is essential when living with solar. Many new owners maintain a daily log of energy in and energy out, plus highest and lowest voltage. Most owners (who have a battery-backed system) eventually settle for daily checking the battery bank’s percentage charge. The latter is all that is routinely needed. Anything needing attention causes significant variations.
Easy to install and easy to read. The Xantrex battery monitor. Pic: xantrex.
Anyone can do this. Solar Success specifically explains how to. Solar That Really Works! does likewise for boats, cabins and RVs. See also the Caravan & Motorhome Book, Caravan & Motorhome Electrics, and the Camper Trailer Book. To know about the author Click on Bio.
See also, associated site: https://solarbooks.com.au