Prompted by the Smart Meter 2 thread, it occurred to me to wonder
whether there was any way in which I could monitor my electricity
consumption in half-hour intervals in order to evaluate whether one of
these fancy tariffs would be good or bad.

[Before I had a water meter fitted by my water company, I fitted my own
meter and ran it for a year or so to see whether I would be better or
worse off with a meter.]

You can buy energy monitors which either use a clamp sensor round one of
the meter tails or count flashes on new-type meters. But they only
appear to give instantaneous readings and daily totals.

Does anyone know of anything more granular - preferable with the ability
to capture the data and insert it into a spreadsheet? Sounds maybe like
a Raspberry Pi application?

If I were to have a smart meter fitted (which I've hitherto resisted!)
but to stay on a fixed tariff, could this be made to provide me with the
required data?
--
Cheers,
Roger