I'm supposed to be hoovering so this is more fun…
If absolutely everything in your generating shed was spot on, the maximum conversion efficiency would be about 34%, so 1kWh of electricity would cost you 8.57p.
More realistically, you might get a conversion efficiency of 25%, with 1kWh of electricity costing 12p.
This means that the conversion efficiency of your generator is critical. High efficiency means big and expensive to buy and maintain. To make the scheme pay, you have to repay the cost of owning the generator within its operational life. That's difficult to do on a small scale. Any downtime will cost you money. To make electricity from gas at an economic rate, you need produce a lot of it continuously and sell any excess production. The economics very much favour the big boys.
Quite a lot of electricity is made from natural gas. After considering conversion efficiency and the cost of generating and distributing power, it's probably not a coincidence that electricity turns out to be about 4 times as expensive as gas per kWh.
I used to heat my house with electricity and was delighted when gas arrived in the village!
Dave
Edit PS: assumes I got the maths right. I am now wearing a tin hat.
Edited By SillyOldDuffer on 04/08/2017 16:58:32