Maximise the self consumption of your solar power with Solar Immersion
With the price that electricity retailers pay you for surplus solar power these days being between 4c to 10c per kWh and the price we pay for power being around 27c a kWh it just does not make sense to send surplus power back to the grid if you can possibly help it. The problem we have is a typical home has a daily power consumption and solar production graph that looks something like the below.
Typical Power Consumption & Solar Production Graph – Note lots of Surplus Solar Power!
With the above graph you can see the following:
Red shaded area representing power which has been taken from the grid at a cost of 27c a kWh.
Blue area is self consumed solar power which is what we want, that is saving us from taking power from the street at 27c a kWh.
Green is surplus solar power; this is solar power which has been generated but hasn’t been used so it has been sent back to the street as surplus solar power at 4c to 10c a kWh, depending on rates paid by your electricity retailer.
With this system we actually put a timer on the hot water system with a 1.8kW element to try and maximise solar self consumption; that’s the big spike in power you can see at around 10am. On this particular day the plan backfired quite badly as 10am happened to be right when a cloud came over and caused a big drop in solar power production, causing most of the hot water to be heated from the grid at 27c a kWh – exactly what we were trying to avoid.
To really maximise the self consumption of solar power we really want something that monitors exactly how much surplus solar power there is and then puts that amount of power to use, and that is exactly what the Solar Immersion device does.
How Solar Immersion helps you use your surplus solar power
The Solar Immersion device connects to your hot water system as well as the mains cables coming in from the street. It monitors the power coming from the grid as you consume power and it also monitors any power going back to the grid as surplus when your solar power system is producing more power than you’re using. What it will do is see exactly how much surplus solar power you have available and it will send exactly that amount of power to your hot water system.
Effectively what the system is doing is using your hot water cylinder as a solar power storage device, a bit like a battery. It stores your surplus solar power effectively as hot water and then you can draw from it at a later time as required.
Solar Immersion Power Consumption & Solar Production Graph – Note Solar Power Self Consumption!
In the above graph you can see the same solar power system as previously shown but this time with the Solar Immersion device fitted. The thing that’s immediately obvious is just how much more solar power self consumption has been achieved! You can see how the Solar Immersion device has sent all the surplus solar power to the hot water system until about 2pm; by that time the water was up to temperature and the thermostat turned the system off, with the remaining surplus solar power being sent back to the grid as surplus.
Solar Immersion – a great way to maximise your self consumption of solar power
As can be seen the Solar Immersion device provides a great way to maximise your solar power self consumption and works out to be much cheaper then even a very small battery bank when it comes to storing surplus solar power, but how much surplus solar power can you actually store in your hot water system? That will depend on 2 factors – the size of your hot water system and the temperature that the water needs to be heated too.
Power required to heat hot water cylinders of various sizes by 40oC
Please note: A typical household uses around 40–50 litres of hot water per person per day.
Tank Capacity (Litres)
Power Required (kWh)
|Capacity of Tesla PowerWall Battery||13.5|
As can be seen from this table a standard home hot water system can easily store more surplus solar power than a battery bank such as the Tesla PowerWall and at a fraction of the cost! Why not contact Gold Coast Solar Power Solutions to see if a Solar Immersion device is right for you today?
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