I had this same problem last year, where my electricity usage stays the same, but then around this time of year the bill doubles.
Electric consumption is higher during august-september months due to hotter days. Fuel costs also affects your consumption rate making your bill higher. Expect lower bills during next months.
No, it is the most expensive way of paying for gas and electricity.
I’m working on a school project where I make a circuit board to emulate a snack machine and I’m wondering how to make a sensor that does this… but I don’t know how to tell a one from a five without using some kind of image scanner/filtering program and thats obviously not how it works since that sort of thing would be too expensive to add to a simple coke machine. Does anyone know how this sort of thing is done in the real-world industry?
You’d be surprised what goes into a "simple coke machine."
"Also known as bill validators or bill acceptors, paper currency detectors scan pliant currency using optical and magnetic sensors. Upon validation, the bill validator will inform the vending machine controller (VMC) or other host device of a credit via a parallel or serial interface. Various interfaces exist for the host device including a single-line pulse interface, a multi-line parallel interface, a multi-line binary interface, and serial interfaces such as ccTalk, SSP, MDB2PC and MDB2USB."
http://en.wikipedia.org/wiki/Bill_validator#Paper_currency_detectors
I have googled enough 
I would guess that getting your electricity from the local grid and best priced supplier will be cheaper for a 415v supply. Depending how large a supply you want you could be charged 1 or 2 pence a unit cheaper than domestic prices (or as much as half if its a really huge supply you need). Cheaper becasue of economy of scale for the generators – they can produce electricity lots cheaper than you.
Generators might be cheaper to run if you can find a cheap source of fuel for them and use the generator over many years, 20 or so.
Answerer above had a good point, why not get a kiln that is heated by the fuel directly rather than electricity? Could be cheaper depending on the fuel of course
