Currently, without incentives, it not realistically feasible to generate power from PV cells and achieve any payback.
Even in southern Portugal, where the number of hours of sunlight are significantly increased, there is little chance of a realistic recuperation of the investment when associated with tariff electricity prices.
However, in late 2009, Mearsecroft Limited became aware of a scheme to encourage small generators to invest in PV technology and achieve a realistic payback of approximately 6 years.
The above scheme for new generators doesn't exist. The replacement scheme which offers payback over a much longer period is on hold pending reconsideration.
Mearsecroft maintain and operate two systems as follows:
System 1:
18 Photovoltaic Modules manufactured by S-Energy, Model SM-225 PA8 - view details
1 Invertor, manufactured by SUNNY BOY, model SB3800V; - view details
1 Tracker 2 axis, model Degertracker 5000NT, - view details
System 2:
This is a similar albeit smaller system comprising:
15 Photovoltaic Modules manufactured by S-Energy,
1 Invertor, manufactured by SUNNY BOY, model SB3800V;
1 Tracker 2 axis, model Degertracker 3000NT,
All electricity is exported via export meters. Any used in the houses is imported off the system through a seperate meter as any normal user. Energy output is monitored by a GSM module.
Payback for each system is estimated in 6 years: - view details
This does not include battery charge controllers or batteries as all power generated is passed to the electricity distribution system. The inverters (to convert from direct to alternating current), wires, conduit, earthing circuits, fuses, safety cut-offs, outlets, trackers were all supplied as one package for each system.
The limitations of the EDP (Energia De Portugal) scheme are two dimensional. Firstly the maximum overall output of any system is 3.68 kW. The second limiting factor is that the maximum capacity of any system may only be 50% of the maximum demand of the attached domestic system.
System 1 maximum demand is 10.35 kVA or 45 Amps
System 2 maximum demand is 6.5 kVA or 30 Amps
Therefore the maximum output of System 1 is 3.68 kW and System 2 is 3.25 kW
What Else Has Been Considered?
No PV system is maintenance-free. Scheduled inspections of the systems are being on an annual basis to ensure that the tracking mechanism is lubricated, the wiring and contacts are free from corrosion, the modules are clear of debris, and the mounting equipment has tight fasteners.
Monitoring of the power output of your PV modules will be carried out to track the system’s performance to help deter-mine whether the system is operating as designed and guaranteed.
Current indications show that the payback is faster than the projection.
A remote monitoring system has been installed to send an alarm should the system shut down. This system monitors current flow from each unit at mid-day. If it is less than 1 amp then an alarm is sent. The system also sends a message once per week to inform on the warning system state of readiness.
For more information contact Mearsecroft
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