Nimrod103 wrote:BT63 wrote:Nimrod103 wrote:...when the winter storms blow, the sun doesn’t usually shine....
Even on sunny days in winter the production of solar is much less than in the summer; the day length is less and the sun is lower in the sky, slightly offset by cold air increasing the efficiency of solar panels.
Typically with solar, the best winter day will only produce one-third of what can be produced on the best summer day.
This summer has seen extreme quantities of sunshine.
Interestingly, I have a friend who is a keen young IT electrical engineer, who keeps close tabs on his solar panels. He tells me that most power is generated on his system when there is hazy sunshine with brightness all over the sky. More than he generates than when there is strong sunshine and a cloudless sky.
I have daily generation and weather data for mine going back over ten years.
The best conditions for me, with my South-East facing panels at 40-degree angle, are a sunny morning, gradually transitioning to increasing quantities of white cloud in the middle of the day, ending with full white cloud cover in the last quarter of the day. Generation is significantly reduced if there is a clear sky late in the day when the sun is no longer shining on the panels.
In winter, snow on the ground works in a similar way to white cloud in the sky, giving a useful increase in generation.
A cold breeze can make quite a difference compared to a hot calm day.
For me, the days with greatest overall generation tend to be in May or early June, a few weeks before the longest day, due to the balance between sun strength and air temperature.
My greatest ever daily generation was 14th June 2012 which was a day with partial cloud and much cooler than typical for the time of year.