Ive seen some data which suggests a 1kW panel array will produce around 850 kWH of energy in a year. This equates to approx 100W average continuous power i.e 10 % of the array value. This figure of course is average UK. It may be more than this in Orford and somewhat less in lerwick. But it means that to produce the yearly amount of power of the 4kW transmitter which is probably using 7kW at least. They need to install a 70 kW array.