Export control allows you to install a larger Solar PV system than has been permitted by reducing the export on the sunniest days only when the electricity is not being used.
Often the greatest limiting factor when installing a Solar PV array is the grid infrastructure. As the distribution grid is designed simply to provide electricity rather than receive it many DNO’s (Distribution Network Operators) are now providing strict limits on the amount of electricity a system can input to maintain the grid’s stability. The addition of an Export Control to the solar PV array provides the solution as it can limit the amount a system produces to the agreed level when it is not being used onsite.
In the UK we rarely see perfect conditions for solar panels, most often systems will generate less than 60% of their capacity (kWp). This means that when a system is export limited, the limitation rarely applies. Further to this; if export limit + usage ≥ current generation, then the system is not limited.
10 kW Solar PV system limited to 4kWp export without usage (worst case):
A 10 kW system in London with its export unlimited would have an annual energy yield of approximately 9,530 kWh. When the system is limited to 4 kW at all times then an annual energy yield of approximately 7,899 kWh is still achievable.
This means that on sites with no electricity demand the loss of earnings is only 17.1%. As the usage on site increases this loss decreases. In cases where electricity use is high there will be no detectable loss at all.
For more information on this or any other Enviko services or products please call Enviko on (England & Wales) +44 (0)20 8816 7631 or (Scotland) +44 (0)131 335 0032 or by email.
The financial logic becomes obvious when you consider that returns on these systems can be as high as 15% and the obvious fact that traditional energy prices have risen far faster than inflation
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