Graig Fatha has now been generating low-cost, green electricity for 6 months! Our members are being supplied by their wind farm, and are seeing savings on their energy bills, every month. We are excited to share the data on this generation.
It is impossible to exactly predict the output of a wind farm. There will always be some uncertainty in any estimates. Therefore we use three different estimates for the output of Graig Fatha, these are:
- P50 – There is a 50% chance that Graig Fatha will generate this amount.
- P75 – There is a 75% chance that Graig Fatha will generate this amount.
- P90 – There is a 90% chance that Graig Fatha will generate this amount.
P90 is therefore the lowest predicted level of generation as it’s quite likely to be exceeded. Our calculations for member savings are based on the middle P75 estimate.
March’s P90, P75, and P50 estimates were adjusted to account for generation only commencing on March 8th.
Graig Fatha generation from April to June was higher than we expected, totalling 1,302MWh over this period. In April & May, generation exceeded even the P50 estimate and in June it exceeded the P75 estimate.
Wind speeds in July and August were particularly low, partly due to the extreme heat the UK experienced this summer. This resulted in lower than predicted output in these two months. Anomalies like these are to be expected from time to time over the lifetime of the turbine, but will not have an impact on the long-term savings and payback period for Graig Fatha members.
In the UK, winds speeds tend to be higher in the winter compared to in the summer. Generation from Graig Fatha is therefore expected to rise over the next few months. This is one of the good things about wind energy, it tends to be higher in winter when people normally use more energy. So members see larger savings at a time when their bills are higher.
Since beginning operation on March 8th, Graig Fatha has generated 2,263MWh of green electricity. This is enough to power almost 800 homes for an entire year! So far, generation from the wind farm has led to CO2 savings of 480,000kg.