well first off read_date and read_time should be stroed as one value, like most db system MySQL stores date and time in a single value, what ever you call it is upto you. Id probably use soemthign like TimeofMeterReading.
total consumption is a derived value (effectively total consumption is DERIVED from the first meter reading (usually on installation) and the current meter reading.
I don't know what your column "reading" is meant to be
You've not identified what is your primary key, Im guessign its going to be a composite of MeterID and the DateOfReading
to find the consumption you need to subtract the previous reading from the current reading
you'd probably use a sub query for that
to find totla consumption you would need an opening meter reading. where or how you identify that is up to
should you have a table for customer
a table for meters
a table for customersmeters (if so that would be a good place to store the initial meter reading)
I'd rather be riding on the Tiger 800 or the Norton