The payback period for photovoltaic modules (or photovoltaic panels) must be considered from two perspectives. Namely;
Economic,
and
Environmental
Economic aspect
This economic recovery will depend on the type and price of the photovoltaic modules, the installation method, the electricity consumed in your home, the rates in your area, if there is an energy export agreement with the utility company, the useful life of the photovoltaic modules, the depreciation of the conversion rate per year, etc. Therefore, it is a simple mathematical exercise to calculate the payback period. A strange man in this job is the human angle. If you waste electricity through negligence or use outdated and inefficient appliances in your home, you will extend the payback period yourself.
Environmental impact
The average man on the street may be more interested in the economic aspects, although this need not be so, since the environmental reward itself influences his own survival on this planet.
But the environmental payoff is the least discussed by the end user when it comes to a sustainable energy solution for their home. Whether it is photovoltaic modules or cogenerators, the manufacturing process and installation consume energy. This doesn’t just start on the factory production line. In reality, the excavation of the raw material itself consumes energy and, from that moment, every stage of the production and installation of the solar module (including the transport of raw material, cables, fixings, etc.) uses energy. This energy is called the embodied energy of the photovoltaic panel system.
How long will it take for PV modules to recover that energy, and how much additional energy will be saved over their lifetime (typically guaranteed 25 years but lasting more than 35 years)? Modern strip / tile solar panels have considerably lower embodied energy than monocrystalline and polycrystalline solar modules.
Importance of environmental depreciation
This is important because the generation of electrical energy used for the fossil fuel photovoltaic module system is a contributing factor to the dreaded global warming. The component production process itself may be causing greenhouse gas emissions. (for example, metal and glass components). Fortunately, waste disposal is not a big deal, as glass and metal are easily recycled, which can happen 35 years later.
Energy Recovery Calculation (EPBT)
The relationship goes:
EPBT (Years) = Specific energy (kwh) / Annual power generation (kwh / year)
Where,
Specific energy = energy required to produce a photovoltaic system
Annual power generation = system power generation rate
The EPBT is about 2 years for the monocrystalline photovoltaic module system. This for thin film and polycrystalline tape type modules boils down to 1.7 years and 1.5 years respectively. This is based on 4.7 hours of sunshine per day as appropriate for southern Europe.
Performance and maintenance
Good maintenance of PV modules is important when the nominal EPBT is expected. The installation must ensure good wind clearance around the modules, the best exposure to sunlight, low-loss inverters and switchgear, and wiring for the least voltage drop and power loss.
A thin film of dust is good enough to dramatically reduce energy conversion efficiency. Therefore, good maintenance is too important for a low EPBT.