Year end results for 2020-21 water year

Here are the 3 graphs I post each year showing the output of my turbine for the past 12 months; in each, the bold black line is the data for the past year:

1. Daily power output:

There was an early pick-up of generation with rain falling in October, and generation was sustained more or less at maximal generation (917 W) through to March when the weather became much drier; generation then picked up again from mid May, during which month an unprecedented 192 mm of rain fell (usual being 90 mm); thereafter output dropped steadily as autumn dryness set in.

2. Cumulative energy (kWh)

This graph uses the same data as graph 1 but presents it in a different way, this time showing the cumulative number of units of electricity (kWh) generated as the year proceeded; it can be seen the end of year total (5167) is the most units ever generated, just exceeding last year's total of  5132; the FiT payments received for this energy will be £1,338 for generation plus £216 for export, totalling £1,554. This amount more than covers our electricity purchase costs which for the same period will be about £400.

3. Power duration curve 

Again this graph uses the same data but shows it in yet a different way. The graph indicates the number of days the turbine performed at various levels of power output; it can be seen it did not operate at full power for as many days as last year (the pale pink line) but it exceeded last year, and all previous years, in generating for more days at the intermediate output band between 700 W and 200 W. There was not a day in the year when there was an output less than 140 W. 

Conclusion: 

With this being the best of eight years in which my Powerspout has operated, it is a very pleasing result; perhaps the years are getting wetter; certainly the National River Flow Archive has reported that the calendar years 2015 to 2018 were probably abnormally dry years, and the wetter years following are likely to represent nothing more than a return to the long term 'normal'.