Why is it that when we are not home and every few nights at 11:30pm we have a high .30kwh usage. No hot water service is connected, everything is turned off except our new fridge. It is only every few nights. We have been away for over a week and it has spiked at this time 3 times!?
A high usage is the highest usage for the day irrespective of what the value is.
.3kw means that you drew 300 watts in that period.
If you are paying 36 cents a kw, then that has cost you 10.8 cents.
Only using a fridge, your consumption for the day should be around 1.2Kw for a 4 Star Rated Fridge.
If the fridge is an auto defrost that may be the reason for the spike at that time.
You will be paying more a day for the supply charge than the cost of running the fridge.
If your consumption is more than the 1.2Kw a day then you may have left a light on inside the house.
A 50 watt incandescent light left on will draw 1.2Kw a day by itself. A 10w energy saver globe would only draw .24Kw for the day.
If you have a sensor light it may also be the reason for high usage, as wind will often cause movement and set off the light. The old type (non-led) often have two 150W globes in them (meaning they draw .3kw for every hour they are on).
At night around that time we have a fridge, freezer, three car fridges, a laptop, TV and a couple of beside lamps running in our house.
Our consumption is around .2kw per hour from around 8pm to 6am each day (2kw a day).