Everyone knows that photovoltaics is about savings, care for the environment and independence. However, not everyone is aware that this type of installation works like a bank deposit with an unprecedentedly high rate of return!
Treat the installation of a photovoltaic system as an investment and enjoy up to 20% rate of return !

Below are 3 examples of photovoltaic profitability calculations. I invite you to read!

Example 1


A family with one child, living in a 150m2 house.

Electricity bills approx. 330£/2 months. Consumption for the last 12 months 3500kWh.

In this case, the photovoltaic installation should be around 4.4kW, so as to produce around 4400kWh, which will compensate for the existing drop system and also leave some reserve for new electricity consumers or weaker weather in the longer term.

The cost of installing 1kW, assuming the use of good quality components, is 4,500£/kW. The family will benefit from subsidies under the 'My Electricity' programme and also from the thermo-modernisation allowance (PIT rate = 17%).

The assumptions take into account the average annual increase in electricity prices 8%. The additional costs associated with the system are annual servicing and cleaning of the modules. The calculation takes into account that the inverter will need to be replaced once during the life cycle of the system.

The above assumptions are summarised in the table below:

Based on the above data, it was calculated:
IRR (*) = 20%
NPV (**) = PLN 56 400

Payback time 6 years 2 months

(*) IRR - definition and interpretation
(**) NPV - definition and interpretation


Example 2

Based on the above data, it was calculated:

IRR = 23%

NPV = PLN 97 800

Payback time 5 years 4 months

Example 3

Based on the above data, it was calculated:

IRR = 22%

NPV = PLN 39 200

Payback time 5 years 6 months

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