Stuart Whitelaw is a Moruya based architect and artist. This is his experience of a grid feeding solar system…
When we built our house in 2000, power from the grid was already connected to our barn on the site, so rather than go stand alone solar with batteries, we decided to install a grid feeding photovoltaic system. This way the grid is your battery (in theory).
Our solar electrician did some research into different types of panels, and we investigated one made by Canon that was based on stainless steel sheets.
As an architect, I am always looking for materials that can solve particular problems, and these panels looked highly durable and it seemed possible that with the right detailing they could form the roof of our carport/ workshop. This concept really appealed, as it removed the need for most of the Northern roof cladding, and also looked really neat.
The installation was so simple, and took less than a day. We clicked the panels together using a ‘unistrut’ type galvanised channel and they form a very weathertight roof. It wouldn’t be passed for a house roof but for a shed no problem.
These particular panels are not around today, so all new installations are mounted on a separate framework on top of the roof. Having the panels capable of tilting to be more perpendicular to the sun’s rays in winter and summer increases the efficiency markedly.
The installation of the grid feeding was a little trickier, as it was one of the first in the district and the Country Energy guys were a little perplexed at first.
The system was turned on only about a week after the panels were on the roof, and have performed without a hitch ever since. Looking at the meter in the box labelled ‘export’ spinning faster than the one labelled ‘import’ was (and is) great entertainment.
When the first meter reader drove in, he opened the box and in a not too happy voice said ‘Oh yeah, I heard about this place’. Having a mini power station at the end of their lines obviously didn’t please some.
We have an 1800w system which, after going through an inverter to make the electrons grid friendly, pumps in about 1500 watts. We have an all mod cons house with a dishwasher and all, and run two small businesses from home. The system provides about 65% of our annual needs. As we update appliances such as computers, we are gradually whittling down the difference in consumption versus production.
As an economic investment, it probably doesn’t rate in current terms. It probably only makes us about 4% on the cost of installation. Better than the stock market in recent times.
The only ongoing niggle we have had with the whole process in the actual billing from our electricity supplier, Country Energy.
The first account we received was pretty confusing, but the dollar number at the bottom was right. There was a little bar graph showing the average daily usage and another beside it showing the greenhouse gas emissions produced by our electricity usage.
When we got our second year’s accounts we were keen to see the difference that our grid feeding had made to our consumption. We were shocked to find that we were using more power than before! Despite our diligence with switching off standby appliances and lights we were no better than a Mc Mansion.
After a bit more study, we found that the graphs were showing the total of both our import and export meters, rather than the difference. The more electricity we produced, the more the graphs showed we had consumed.
Luckily the dollars were correct. At the moment it is a simple deduction process, we get charged for the difference between production and consumption at the normal rate.
As consumers that are trying to do their bit, we felt that the least the electricity company could do was to show the actual consumption and greenhouse emissions in their nifty graphs. A little encouragement never went astray. It was obviously an oversight, and one easily corrected (one would think).
I rang the inevitable hot line and was told that there was about to be action on this very item. This was 6 years ago. Lately the story has been that the software is part of a huge system designed in New Zealand, flogged to most of the power companies, and would cost many hundreds of thousands of dollars to rectify.
It would seem to the naive that putting some plus and minus signs into a program should be pretty straightforward, but that’s bureaucracy for you. It speaks volumes to me about the attitude of the power companies towards the private renewable energy producers.
Maybe I should just refuse to pay the bill because it is showing false and misleading information? Maybe consumer affairs would be interested?
Despite these annoyances, I would still recommend a grid feeding system.
However, solar hot water has to be the first cab off your renewable rank (apart from building your house the right passive solar way) because using an amazing product like electricity for process heating is just dumb and inefficient.
Our Solar hot water system is a 500 litre heat exchange tank with 2 large solar heating panels. We have a manual switch to boost it (with electricity) when needed. Because of the large capacity, good insulation, and the efficiency of the panels we can get through 3 days of very overcast weather without boosting. In winter we boost with our own wood in a small slow combustion stove with a wet back. We have used electrical boosting on about 4 occasions in 7 years.
Once you have something like this on your roof (and this one really does pay the bills) have fun and feel good with a grid feeder. It is possible to be neutral with a system of 1800w, but you will have to be a little more careful than we were in appliance selection. In 2000 there were not the energy efficient fridges around that there are today. Make sure, for example, that if you have a dishwasher and washing machine that they can take in hot water (from your solar hot water system) rather than having to heat it (with electricity).
A nearby house that I designed has a 3.6kW system installed, and the owners are only there about half of the year, so they will be perpetually in credit. They are convinced that the days of cheap energy are past and want to be sure of their comfort in retirement.
It is inevitable that the price to producers of green power will have to rise if we are to get anywhere near the greenhouse targets the government is talking about. The German model shows what can be achieved in a short time. We need to see solar hot water panels on every roof (how can anyone call them ugly?), and grid feeding arrays on every garage.
Thanks for the good news story. The community-owned property that I work for also has a grid-connected power system and a solar HWS. We’ll be using a VIC govt. grant to improve the building’s efficiency and to demonstrate some of the best options for energy use reduction that are available to most home owners.
I’d like to see some sort of mandatory standards for carbon emission reductions in commercial and rental properties. We currently live in a highly inefficient rental property in which we can’t do much to reduce energy use. We run the house on 100% green (wind) power from the grid but it is very expensive as we use it for all the usual things plus space heating. There is a gas heater in the living area but this is the only gas appliance. Given that the gas company charges ~30c per day just to have access to gas, and we’d only need the heater for part of the day and part of the year, it isn’t cost effective to use gas here. So we rely on electricity to drive the intolerably noisy old inverter-style heaters or the energy-guzzling panel heaters. The main problems are that the house faces east and it has large areas of single glazed windows in old aluminium frames – as bad as it gets – and they’re not suitable for the use of ‘double glazing film’. There doesn’t seem to be anything we can do to get the landlord to address the inefficiency of the building (within its physical constraints). Surely if anyone decides to rent a home or office, this is a commercial venture that should trigger a requirement to comply with a reasonable standard of energy efficiency. I can see there being some serious social equity issues for those who are trapped in energy inefficient rental accommodation, can’t afford ‘green’ power, can’t afford efficient heating where the landlord won’t pay for it, yet face rising energy costs. The PM says that the carbon trading scheme will subsidise those who can least afford to pay the additional cost of energy and who can do little or nothing to significantly reduce their energy use at home. This is commendable but it would also be good to see landlords required to provide a broadly acceptable standard of energy efficiency in their rented premises.
Congratulations Stuart on a comprehensive summary. Required reading for those Local Goverment Councils who have not developed policies on the installation of solar power.
Great story Stuart, and encouragement for those of us about to embark on design and construction of sustainable housing in regional NSW. Any idea why the particular solar panels you used are no longer available?
What a good summary of how to do it…..answers the questions I reckon lots of people have.
After reading your story we were inspired to sink our tax refund into a solar hot water system. Local Narooma contractor Gary Leahy from Horizon Plumbing was an excellent one-stop-shop, organising all the paperwork, rebates, and change-over installation within a day.
Our hot water is now off the impending vagaries of the grid supply, and I’m sure the sun heated water has a different feel – maybe its all that vitamin D!
Just got our first power bill in after connecting to solar hot water. Was buzzed to look at that little graph line that comes on the invoice showing recent power usage and watch that little sucker drop off the edge of an abyss! Woo Hoo!
Stuart,
Thanks for your comments. I have been looking for a photovoltaic roof panel that can be integrated into the roof but I am having difficulty finding one. I understand that the Canon panel can be used in this manner but I cannot find details. Can you help?
hi Paul w,
The whole PV market seems to operate in a pretty random way. the panels are a pretty low output per sq.m so probably are not competitive today. Seems a shame as I much prefer to integrate the panels.
If they are roof mounted, the advantage is that you can (manually) adjust the angle twice a year for an improvement in efficiency.