Dr. Art Hunter, CACOR Board of Directors reports:
A Layman’s Explanation of Solar Energy, Tesla Battery and Grid Interaction with a Home.
- The time is just prior to midnight 11:54 p.m. (the date is 2019-03-01)
- The batteries are still at 54% charge state. The reserve limit is 50% so there is still energy capacity feeding the house.
- The Performance is saying 61% home consumption was self powered. The target is 100% but it is a delight to see this growing as the season changes. The past couple of winter months have been simple miserable for solar energy production.
Note: This graphic is indicating that the system is OFF GRID at ll:53 p.m. with 2.4 kW of power being supplied by the battery. To put this into perspective, the home base load at night is about 500 Watts and the geothermal system, at this instant in time, is drawing 1.9 kW heating the house.
Note: Today was a 27.3 kWh solar production day and 19.6 kWh was drawn from the grid. There are still 8 panels covered in snow/ice so production will improve and as the heating season winds down, consumption will also decrease. As this happens, I will also reduce the battery reserve down to 30% or lower to extend the time the home is off grid. The intent is to keep some emergency reserve but one must be willing to take some risk when there are no weather warnings. Eventually this will be automated but I must do this manually so I know what AI logic to build into the control system software.
Notes: Demonstrating Energy flow dynamics
- Sunrise, according to the solar production yellow curve, was about 07:00 and sunset was about 17:30. The days are getting longer. The flat top is saying the arrays are saturated and delivering their maximum capacity. It was a near cloudless day.
- From midnight until about 08:00 the grey curve on the left shows power delivery from the grid. There was no activity from the batteries as they were on standby at their reserve level of 50%, waiting for a grid outage.
- The green curve, below the x-axis, is the battery which started to charge above its reserve setting about 08:00 as the house demand was fully satisfied by solar and the excess delivered to the battery. Then as the sunset at 16:00, the battery started to deliver power to the house and was 100% responsible for the home energy consumption until midnight and beyond. Here sunset and sunrise are not the times used by meteorologists but are the times when these solar arrays start and stop production.