The formula for calculating its value is through an equation of the type:
Value = A x (T-T0) + B
B is a constant supplied by us, which corresponds to saving the time value T0 (for example the 0 hour 1/Jan/2012) in kWh
A is a constant supplied by us, which corresponds to the current rate of savings in kWh / h, ie kW.
T0 is a constant supplied by us, which corresponds to the time of counting time, for example the 0 hour 1/Jan/2012.
T is the time in hours from the time T0 which must be calculated by Francis each refresh counter.
I'll give you an example of the calculation of these constants, considering the 1418 LEDs that were installed at traffic lights in Jul/2011 (PPEC 2009-2010).
These LEDs generate savings of 470 MWh / year compared to incandescent lamps that were replaced.
So now saved half a year in 2011, then on 1/Jan/2012 electricity savings of 235,000 kWh was already. Then:
B = 235,000 kWh
As a year has 8760 h, then the rate of savings is 53.65 kW (470 000 kWh / 8760 h). Then:
A = 53.65 kWh / s
Now imagine that the meter was already running, what is the value this Monday by 10 am, Francis would have to submit?
The day is 316 days since 12/Nov/2012 1/Jan/2012, and we will add 10 hours. Thus no. seconds is 24 * 315 = 10h + = 7570 hours
Value = 53.65 x 7570 + 235000 = 641130.5 kWh
For that value of A, 1 kWh will pass on the counter every 67 seconds.
The values ??of A, B and T0 would be provided by us at Francis with a periodicity set, or, ideally, you were empowered to enter these values ??on the site.
Naturally we have previously set the report justifying technically these 3 values ??and should always be available for consultation. I would say that a click on the counter was open that document.
The conversion to CO2 or € is always very confusing because the relationship to the kWh is always vary. In CO2 due to the importance of renewables, due to increases in €.