Gas m3 to kWh

I am so very close to finishing my gas metering.  I just need a little help with the graphs.

I am counting the pulses and sending the value to emoncms.org every 15mins. http://emoncms.org/StuntMonkeh&id=2850

I can track peak usage m3 over the day but I would ideally like some way of counting the total number of kWh used per day.

My guess its all to do with the processing of the feed but I have had a play around but I can't figure it out.  Can someone be so kind as to point me in the right direction.