The goals of my home brew off-grid solar storage system are:
- make my house relatively black-out proof – keep the lights, fridge, hot water and internet running
- run big daytime loads direct from solar – the pool, the air-con
- reduce my effective electricity cost to $0.10 per kWh assuming a 10 year life of the system
- cover the capital expense with two years of savings
I need to generate around 1 megawatthour of electricity each month to do this.
Based on the performance of my current system, in summer I need 5 kilowatts of solar panels, but in winter I need significantly more, around 10 kilowatts.
I have 3 kilowatts on a 2.8 kW grid-tie inverter already and I want that to export like crazy to maximise my return.
A key reason for building an off-grid solar system is to avoid losing my feed-in tariff. That’s going to take some dancing at some point after SAPN look at the NearMap photos and notice I have a bunch of new solar panels.
In the short term I need around 6 kilowatts of extra panels to generate all the electricity my household consumes.
Of course I will need to focus consumption into daylight hours as much as possible because that’s easier than storing it. My largest nighttime consumer is the pool but I can just change the timer. If I have a surplus and my car is home I will charge it. That will be a whole other project 🙂