Jim Moffat shared:
What happens if you overpromise and under deliver?
Time for a wee bit of arithmetic:
When a developer claims that a solar plant will produce enough electricity for X homes, ask how many homes it will power in January when those homes need it the most.
The Southill Community solar project when it was built was rated at 4.5Mw. On their web site they have been kind enough to detail how much they produce. Since it became operational in November 2016, it has actually generated 18,130Mwh (megawatt hours). That is 51 months or 4.25 years. So over the past 4 years it is averaging 18,130/4.25 = 4,266MWh per year.
The average UK consumption of electricity per household is 3.7MWh/year so on paper you might say that such a plant could provided enough electricity for 1,153 homes.
Not so fast mister.
That solar farm is producing the bulk of its electricity at the wrong time of year.3.7MWh/year/household = 10KWh/day. Lets increase that by 12% for January = 11.2KWh/day. Over the past six days, Southill averaged only 3360KWh/day = enough for only 300 homes .If you wanted to be self sufficient on solar, you would plan for feeding 300 homes – the trough not the average. You can store the electricity in the day in batteries and deliver it at night (with some loss in the process), but no-one has come up with an efficient way of storing panel energy produced in June for consumption in January.
When a developer claims that a solar plant will produce enough electricity for X homes, ask how many homes it will power in January when those homes need it the most.
https://southillcommunityenergy.coop/live-data
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