PV*SOL Expert 6.0 - Manual - Valentin Software

4.7 Economic Efficiency Calculation
The economic efficiency calculation in PV*SOL®, according to the net present value
method, is based on the following formulae:
The cash value (CV) of a price-dynamic payment sequence Z, Z*r, Z*r² ... over T years
(lifetime) as per VDI 6025 is:
q: Simple interest factor (e.g. 1.08 at 8 % simple interest)
r: Price change factor (e.g. 1.1 at 10 % price change)
The following applies for the net present value:
Net present value of the total investment = Σ -dynamic [CV of the payment price sequences
over the lifetime] - investment + subsidies
Positive net present values indicate an investment which can be assessed as economically
positive. The pay-back time is the period the system must operate for the investment to
yield a net present cash value of the overall investment of zero. Pay-back times of over 30
years are not supported. If the CV of the costs is converted into a constant sequence of
payment (r=1), then the following applies to this sequence Z:
Z = [CV of costs] * a(q,T) with a(q,T): Annuity factor ( = 1 / b(T,q,r) for r=1)
The following applies for the electricity production costs:
[Electricity production costs] = [annual costs Z] / [annual electricity generation]
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