End of year results 2019-2020

30th September marks the end of the 12 month period I use as my 'accounting year'; it is when I bring together data for how my Powerspout has done.  

The graphs below show how it has performed:

• in each graph the bold black line represents the data for the year just ended; 
• data is available because it is automatically captured by the installation's inverter (SMA WindyBoy) and transmitted by Bluetooth to a desk top display (SMA SunnyBeam), from which it is downloaded at the end of each month to a desktop pc.

Graph 1 shows power each day measured in Watts (left hand axis) and energy measured in kWh (right hand axis). 

• the power data is derived from the energy data by dividing the kWh figure by 24; 
• the value given for power is therefore the mean power generated in each 24 hours; 
• the figure will be reduced by any event during the 24 hours which interrupted generation, and such interruptions are seen as a downward spike in the trace;
• interruptions include events such as grid outages and turbine stoppages for maintenance; 
• it can be seen there is not a single day in the year when the turbine failed to generate anything at all; 
• sustained upward or downward steps in the trace are caused by a change of nozzle, either to a bigger or a smaller one, to suit seasonal changes in flow; 
• I had to change nozzles 22 times during the year; 

Graph 2 shows the cumulative energy, measured in kWh, generated over the 12 month period. 

• the output this year has been unprecedented, 5133 kWh, far exceeding the totals in the previous 6 years; 
• the cause of this bounty was a wet winter which started unusually early in October and continued through to March, with exceptionally heavy rainfall in February; 
• such wetness gave the turbine a stretch of generation at maximum output (920 W) lasting just under 160 days (26th Oct to 30th March).

Graph 3 shows how many days in the year a given level of power was achieved. 

• this way of displaying the turbine's output gives an idea of how much time the turbine spends generating at different power levels; 
• for example 200W was generated for the number of days between 260 and 315, i.e. 55 days; 
• but these 55 days would not have been in one stretch; this type of graph aggregates all the days in the year which saw generation at this level;
• Graph 1 shows most of the 55 days were in June / July with a few being added at the end of September; 

Graph 1

Graph 2

Graph 3