The following tables show the monthly and accumulated results from the Greeny Flat Experiment plus the operating costs for our first year. (Click on any highlighted month to see a brief analysis of the results for that month and see below for more information on what these numbers mean).
An important aspect of the Greeny Flat Experiment was to monitor it’s performance in order to prove that it met our original Project Goals. The table above shows the results of the monitoring. The terms used are explained briefly below.
- Energy Exported is the amount of electricity that we sent to the grid when our solar power system was producing more than we were using in the house.
- Energy Imported is the amount of electricity that we took from the grid when the solar power system was not producing as much energy as we were using in the house.
- kWh stands for Kilowatt Hours and is the standard unit of electrical energy that the power company uses so they can bill us for how much power we’ve used (and pay us for the power we make).
- Town Water is the amount of water we used from the town water supply
- Tank Water is the amount of water we used from our rainwater tank
- Outdoor Min is the coldest outdoor temperature (in degrees centigrade) that we recorded over the last month
- Outdoor Max is the warmest outdoor temp for the last month
- Indoor Min is the coolest it got inside for the month
- Indoor Max is the warmest it got inside for the month.
*The results marked with an asterisk are unusual because they occurred while we were away and no-one was living in the house so these have not been included in the max/min temperature numbers*
The table below shows our entire running costs (heating, cooling, hot water, electricity, and water charges) for our first full year. Because the Greeny Flat is a secondary dwelling there are no additional rates, sewer or water connection fees. These are paid by the landlord (my mother in this case). If the Greeny Flat was on its own piece of land we would have had to pay a lot more in connection fees. We’ve paid a small amount for the additional town water we use but apart from that our only operating cost is our electricity bill. And, because we’ve exported nearly four times as much electricity as we’ve imported, most of our electricity bill is comprised of the daily fee that everyone pays simply for being connected to the grid. In effect we’ve paid about $260 to use the grid as our energy storage for a year rather than paying a very large amount to install an actual battery system.