aaaaaaaaargh algebra. Calculating baseline emissions for a NHS Trust in London. If bleeedin' electricity companies actually gave meter readings on their bills rather than just cost it would be seemples. instead I have to work out lots of nasty calculations, cos theres different tariffs for day and night. Also it would be nice if the companies wanting baseline emissions calculations actually gave you all their bills, not missing the odd month here and there and making me estimate things. Grrr