Use initial value for a function

[VSEE1906]

Hi,
Perhaps this is a silly question but I want to project a variable Named Energy Intensity using an initial energy intensity value and a constant rate. The aim is to obtain for Time 1 the energy intensity as follows:
Initial energy intensity*(1+rate)

So for Time 2 I want the energy intensity to be Energy Intensity in Time 1*(1+rate).

How can I do this In Vensim?

[tomfid]

1. Use an exponential:
Intensity = InitIntensity*EXP( time*rate )

2. Use a stock:
Intensity = INTEG( change in intensity , initIntensity )
Change in intensity = intensity*rate

2 is better if the rate is time-varying.

[VSEE1906]

Thanks a lot!