First 10 unit day and it isn’t even spring yet
Yesterday was our first 10 unit day for the spring, but we still have almost a month to go till we get to spring time. Most of the winter we have been getting 7 units on a good day and then as the days lengthened we started to edge up and yesterday it was our first day of 10 units. By giving 6 of those units back to the grid and with the savings of what we used ourselves we made about $3 for the day. It doesn’t seem much but it mounts up over the year and those $3 a day is much better in our pocket than in the utility company’s.
Solar Power Cost & Benefits
The benefits are starting to flow now, even in mid winter. Our late fall and early winter was sunny during the day most days. We have been producing about 7 units a day when the weather is fine. We have just gone into a week of bad weather and our production is between one and two units when we have low cloud, wind and rain. On these days we don’t give any power back to the grid.
However on good days we typically use three units during the day and anything left over goes back into the grid. In 61 days of late fall, early winter we produced 336 units of solar power of which we used 182 and sold 154 back to the grid. Now the cost per unit is nearly 19c a unit it all mounts up and when we receive 40c a unit for what we sell back to the grid it will be even better. This was supposed to start 1 July but I see on the power company website that they have pushed it back yet again – until August this time.
How much power did our solar electric panels produce this fall?
We have had solar power on at our house now for 3 months and expect to see the results in our next power bill. We are now at the beginning of winter and we can expect some cloudier days over the next months than we’ve had over this wonderful fall period. So what have our results been?
On a sunny day in early fall we were producing 8kwh per day from our 1500 watt solar electric panels, of which we used to use about 3 and put 5 back into the grid as long as I didn’t use the oven. Now the days are shorter and over the last couple of weeks the amount we produce on a good day has dropped to about 7kwh per day. On a day when there is some cloud we produce about 4 to 5 kwh and on the couple of days we have had heavy cloud we have even managed to produce about 2kwh. Overall that is 690 kwh for three months, or 230 per month. We have returned just less than half to the grid as we are now using heating.
We are happy with these results.
Solar power on your house is like having your own power station
“Having solar power on your house is like having your own power station on your roof and you can sell any excess back to the power company grid. Make money instead of paying.” These were rather grandiose statements attempting to get people to take an interest in their tent at a garden show. Yes, it is accurate. Solar electric panels do produce a good amount of power in areas which have a good amount of sun. And yes, any excess power can be sold back to the power company where arrangements have been made for this to occur.
But how does this happen? The sun’s rays shine onto the solar panels and make electricity. Each solar panel is made up of a number of solar cells, usually called photovoltaic cells (PV cells). These cells are made of silicon which is able to turn the sun’s light into electricity.
Electricity is then drawn off and sent through an inverter which standardizes the flow and amount of power so that it suits the household’s requirements and the needs of the grid that takes any of the excess power. Any power made is first used within the house for all those myriad of electrical appliances we use: the coffee maker for a cup of coffee, the standby power supply for your video, TV and music system, the microwave oven, computers and games consoles.
Any power left over is fed into the grid and you get paid. The amount your get paid is often called the “Feed In Tariff”. This tariff varies according to your state, and sometimes district or supplier.
All of this happens in silence and with no emissions beyond the making of the solar electric panels and inverter. The figures often given suggest that a solar power system for you house is zero emission free within two years. All power produced after than time reduces the total carbon dioxide load in the universe.
Does a solar power grid connect system mean your house will always have power?
I came across an advertisement for a company supplying solar power for houses. It said, “With a Grid Connect System you do not require any batteries and with the Grid as a back-up, you will never run out of electricity.”
This isn’t entirely accurate. Well it is true that you don’t require any batteries. But it isn’t true that you will never run out of electricity. If there is a power cut in your area your inverter will automatically cut out so that the electricity you produce isn’t fed into the grid and so avoiding electrocuting workers who might be repairing the lines or transformers.
Under normal circumstances you will never run out of power as you have the usual supply company providing additional power if you need more than you can produce yourself. But if the weather gets atrocious and lines get blown down, if transformers blow or if there is any other reason that your street doesn’t get power then your solar system will be shut down as well.
When we discovered this the next question we asked was, “Well can’t we just set up some batteries and work off them?” We found out that it wasn’t that simple. A battery system requires a second and different inverter. It was cheaper all round to have a back up generator for those few hours and days a year we are without power.
Solar power for house off the grid
We had a telephone call from a friend in New Zealand this morning. He was delighted to talk solar power as he was going to have to be off the grid on the rural property he had purchased.
He told us that the policy had changed as regards electricity in New Zeland. Previously the government had made it a requirement that the government owned electricity company provide power to anyone who wanted it provided they lived close to another on the grid.
Several decades ago the government sold the electricity company and the laws about how it functions have been slowly changing. Our friends said that the company has been told it need no longer maintain power delivery to those places where it is not economic.
The block of land they have purchased is in one of those areas which is uneconomic. While they do have power laid on to houses in the area at the moment, they have been told that any breakdown in services will have to be paid for by the consumers, not the company. As a result they have decided to go completely off the grid right from the start with their new house.
Laws, social conditions and costs are very variable around the world and constantly changing. These factors impact greatly on the decisions we make about how we live.
Preconceptions about solar panel productivity
I am constantly surprised at how little I had thought through the issues of having solar power in our house. I hadn’t realized I had a preconception that 1500 watts of solar electric panels would produce 1500 watts. Well it can – under ideal conditions – and we have seen that magic 1500 figure a couple of times. However mostly it produces about 1350 watts in full sun at the peak of the day.
Once I got over my mild surprise at realizing I had the unconscious understanding that the panels would provide full power all the time I then had another surprise and that was how much power the panels would provide just as the sun goes up and down. The sun is just creeping over the horizon very early in the morning before most people are up and about and the inverter shows 38 watts. Not much I admit but it is still before 7 in the morning.
Solar power cost vs value of a solar powered house to you
There is no easy answer to the question of solar power costs as it depends on so many factors. The hardware consists of panels, the inverter and the mounting system you use plus you will need to add the cost of labor to get it all up and running.
The types of panels and inverters easily available and sold locally to you will vary considerably according to what your suppliers have chosen in your location, whether you wish to purchase your hardware from outside your district, and whether you have the skillset (and the law allows it) to do some of the work yourself. You also want to factor in how long your hardware is likely to last. Some inverters are said to last only five years or so, and others much longer with an expectation of up to 20 years for some.
The core components of the decision to go solar are likely to be:
- the current cost of power in your district,
- the likely increase in power costs in the future,
- current subsidies from state or federal government
- any payments you may or may not get for feeding into the grid
- the likely life span of your hardware (if a $3000 inverter lasts 5 years it costs $600 for each year of use, but if it lasts 20 years, it costs only $150 a year)
As an example –
We started to think of going solar here in Western Australia when the subsidy from power prices started to be lifted and we were notified last year that power would rise from 13c a unit to 20 cents a unit over 12 months.
In addition the Australian government provided those who purchased new panels with a subsidy by way of Renewable Energy Certificates (RECs) which companies selling could use to reduce the cost of solar power for your house by $4000 per kilowatt of panels installed (up to a limit).
On top of all this the State is going to require the local energy companies to purchase energy we return to the grid at 60c a unit as at July 1, this year (2010).
All of this improved the financial dynamics considerably and effectively reduced the solar power cost. The full price for our 1500 watt system with a 3300 watt inverter (so we can add more panels later) was $13,110 but we received $6000 back as a rebate on our RECs. This was a more expensive system than some available but it did come with a 20 to 25 year life expectancy and was a good German make.
We are currently producing on average 7.5 kwh (or units) per day and on July 1 will pay 20c per unit -
7.5 kwh/day @ 20c /kwh = $1.50 per day or $547.50 per year
In March 2010 when I am writing this we are in that season when we need little air conditioning and no heating and so the 40% we are returning to the grid will be high. When the weather changes we won’t be able to return as much as I work from home and like to raise the temperature to 22 degrees Celcius (72 degrees Fahrenheit) – and in summer drop it to 27 degrees C (.80 degrees Fahrenheit). But if I can arrange our lives to return one third to the grid then the comparative figures are as follows.
5 kwh/day used @ 20c /kwh = $1.00
2.5 kwh/day returned to the grid @ 60c = $1.50
Added together we save $2.50 per day or $912 per year.
This means that our unit will take about 9 years to pay off with savings.
However that is not how I look at it. This is for us an investment in our future when power costs will go up and our income is likely to go down as we move into our later retirement years.
If I think of this as a 20 year investment and we return $912 a year for 20 years (and allowing for the cost) we will get to keep just over $10,000 of that. This works out at about 5.1% a year for no risk. This is over 5% a year with no concern for what the markets do, and at the moment without any tax implications.
I think it is better than money in the bank because banks can and do fail. And money in the bank is paid interest which is taxable. For us this is part of our “secure” superannuation program for our old age. And of course if the price of power doubles again, as I’m sure it will then the savings will be very much more than 5%. If the price of power doubles and the payment for power fed in to the grid remains the same the return would be about 16% on our money – which is OK by me for our old age.
[Of course nothing is guaranteed. This, like any investment, might fail! And the inverter lifespan might be overly optimistic. One thing is for sure, though, and that is the price of power will go up.]
Solar Power For Our House
There is something quietly addictive in having solar power on at our house – addictive in that we keep checking to find out how much our panels are producing and how much we are saving. I have not bothered about how much power we have used in a day for years, other than in a general way when I was aware about keeping overall costs down through not overusing the air conditioning in summer or heating in winter.
It is quietly satisfying to see the kilowatt hours clock up on our inverter knowing we are saving money on our next bill and contributing in a small way to the reduction of greenhouse gases in the world. We regard the solar power cost as an investment in our future. Of course a variety of government supports has helped to substantially reduce the cost to us. But the basic reason behind buying it was that the cost of power is in the process of doubling over a couple of years in our state and while we currently have a comparatively large income, from June it is going to halve when my work finishes. We can afford it now. In the future at some stage we will be retiring and it is good sense to aim for reduced bills then.
I have been interested in having solar power for decades, but never got around to finding out much about it. I always had the idea that I could learn how to do it myself, but I never got around to finding out how. Excuses, excuses…
Anyway we finally decided to go solar and a fortnight ago the panels and inverter were installed. In 15 days we have produced 117 units or kwh of power. That is an average of 7.5 units a day from our 1500 watt system, despite several days of heavy cloud and 70 kg of CO2 that is not going into the atmosphere. This is more than the 5 to 7 kwh we were told we could expect.