Today I intend to lay out a system that works well in harnessing the power of the sun, without the need for any costly solar power batteries.
Keep in mind this is not an article that is anti solar power. It is merely an article that questions the unnecessary waste and cost associated with paying for batteries to store solar power, when it may be of limited benefit.
The main drawback on solar batteries is that they have to be replaced after several thousand charges. While this may not sound like a big deal, in fact it adds significantly to the cost of a solar power installation for very little benefit in return.
In fact, in cost terms you would need to replace the batteries every six or seven years. You can’t really do this yourself – most households would need to get their installer to come back and reinstall the battery for them.
This is something that is usually not costed upfront in solar power proposals. In practice it can’t be – technology and costs will change rapidly over seven years, and inflation will take effect as well.
So if your solar power system saves your household $1000 of energy cost per year over seven years, just how much of that will be eaten up by unexpected maintenance costs when your battery needs replacing?
And what impact would that have on the lifetime value of your solar panels?
A Better Way?
I am not saying that a battery is a bad idea in all cases. There may in fact be some instances where a battery could be useful, such as where you have a large (3kWh plus) installation and virtually no daytime use, alongside very heavy power consumption in the early evening only. But this is fairly rare.
There is in fact a better way to set up your household energy system where you can get access to cheap nighttime rates and still gain access to solar energy production during the daytime.
This involves switching your household ICP to a day and night meter. Most power companies have the option for you to switch over to day and night, which simply provides you with slightly higher energy costs during daylight hours (between 7am and 11pm) and far, far cheaper unit energy costs during night (11pm to 7am). The reason for this is that far less energy gets used by households at night relative to a consistent supply and many retailers are willing to charge off peak rates for it.
The way this works in practice is you ring the power company and ask you to switch you over. This often involves a call out fee and a once off cost of $50+GST. In our case this paid for itself within two months. Keep in mind however that some energy retailers may be reluctant to switch you on to a day and night meter when you have solar panels installed, for no other reason than they might feel you are picking their pockets too much.
Once we did so, we went from paying 22c per kWh any time of day or night to paying 24.3c per kWh during day rates and just over 8c per kWh during night rates.
The other option is switching over to wholesale energy rates, which tend to be much cheaper at nighttime. This isn’t always ideal for solar, however, because companies that offer wholesale energy rates generally compensate by introducing higher fixed costs and daily charges – meaning that even if you reduce your consumption, your bill won’t go down all that much.
So, if you’re smart, you can use your solar power installation to mop up your daytime consumption, and then just switch over to nighttime rates instead of needing to buy (and replace) a battery.
Another thing I do is bring most of my early evening consumption into daytime use, to take the strain off the grid (and my pocket) during peak evening hours.
One of the ways I do this is by preparing most of my meals in a slow cooker. I estimate that to prepare a family meal draws between 2.5 to 3 kWh from the grid every night if you are preparing it on an electric stove or in an electric oven.
By spreading this energy consumption across the day using a slow cooker, I save myself all this energy, which amounts to 60-80c per day in energy costs. I might even eat my dinner by candlelight and just turn on a lightbulb to read a book.
The result is a day where there is often no draw from the grid during daytime peak hours, and then just a very easy draw from the grid during the evening. Then my power usage switches to the night meter which is so cheap I don’t have to worry about it.
I conclude that this light usage model will work out to be far cheaper, with far better return on investment, than just about any other solar power system, especially when taking into account the environmental costs of production involved in various system components.
