Close scrutiny of the three graphs below reveals all that is important for learning how productive my installation has been. All three graphs are derived from the same raw data and that data is a record of the number of kilo-watt-hours (kWh) generated each day. This data is captured automatically by the SMA inverter, transmitted wirelessly to an SMA Sunny Beam and downloaded each month from the Sunny Beam to my computer.
In each graph, the bold black line represents the results for the 2017-18 "water year" which has just ended. Previous years are shown for comparison.
- With a total of 3816 kWh generated, it has been the second most productive year so far.
- The year started slowly with less energy generated than previous years up to the end of December
- From December onwards output then exceeded previous years through until mid-May
- From mid-May onwards, output fell to being less than most previous years
- The good output between December and mid-May was achieved through peak generation hitting just in excess of 900 W whilst in previous years it had not exceeded 800 W
- This higher level of generation was made possible within the limits imposed by my abstraction licence by knowing with greater refinement the volume of water the turbine was actually taking and operating it to within the upper margin of error intrinsic to the way the volume imposed by the licence is calculated.
- The volume of water extracted for the year totalled 45,791 m3. My licence limit is 49,982 m3.
- Capacity factor for the year was 58% (using as datum the design power of 750 W; calc: 3816*100 / [0.75*24*365] )
- Availability factor was 100% (non-availability of the turbine for generation, whatever the reason, never exceeded 4 hours in any day; I only count whole days as being an impairment on the availability factor).