Appendix

General recommendations for PV-system projects

1. PRE-FEASIBILITY STUDY

Such a preliminary study should contain the following items:

• Energy consumption patterns of the potential users, with special emphasis on electricity consumption presently and in the near future, based on peoples' expectations and income levels.
• Economic and financial comparison of alternative renewable energy and conventional (diesel generator sets) options. In such comparisons non-financial arguments should also be discussed.
• System sizing study based on present and expected energy consumption figures, solar radiation figures and system specifications.

2. SELECTION OF MANUFACTURER/SUPPLIER

When this pre-feasibility study results in a positive recommendation the next step is the elaboration of the design and selection of manufacturers/suppliers.
In cases where substantial amounts of money are to be spent on equipment, tendering is worthwhile. As a rough estimate, tendering becomes interesting when the procedure costs less then 5 to 10% of the sum involved.
Tendering in such cases has the following benefits:

• it ensures product quality, if well carried out;
• it ensures proper sizing of the equipment by setting specifications on performance which are less than specified by the manufacturer/supplier;
• it can ensure proper installation and commissioning of the equipment.

On the other hand tender preparation has considerable costs. To give some indication, even for small projects at least one man-month should be considered.

For all PV-system projects quotations of at least three manufacturers/suppliers should be called for. In the competitive business of PV-systems, unit prices might not vary so much, but secondary conditions such as guarantees and after-sales service could show interesting differences.

A very strong argument in the selection of a particular manufacturer/supplier is their already existing market share in the region and the presence of a local agent of such a company.

In the final agreement of delivery of goods the following points should be covered:

• point of delivery of goods and price at delivery;
• storage costs at point of delivery per day;
• type of packing: number of crates, quality of crates (for sea and air transport) and list of contents per crate;
• payment procedures of the order and expiry date;
• calculations on sizing of each independent system and assumptions made for such calculations;
• manuals on the installation, operation and maintenance for each independent system and system component;
• specifications of each system and system component and applied rules and standards, including tolerable operating conditions: all system components should be suitable for operation in the humid tropics and marine conditions: battery regulators, lighting armatures, switches, division boxes should be drip-water proof;
• guarantees and after-sales service: conditions for guarantees and financial consequences should be specified: transport of defective components, on-site repairs, etc.;
• spare parts list for a two years' operation period.

Caution should be exercised with respect to the transport of the equipment a complete insurance for goods and transport should be arranged.

3. TRAINING OF USERS

Training of the system users should be provided in advance of or at installation. This should ensure proper use and awareness of the systems' limitations.
Subjects which should be dealt with are:

• applications for PV-systems and its scope;
• basic working principles of the PV-systems: discussion of the functions of the system components;
• operation and maintenance requirements;
• some practical trials to show the effect of shading on the output: effect of battery depletion etc.

4. INSTALLATION OF PV-SYSTEMS AND TESTING

If the organisation which purchases the equipment claims to be experienced in its installation a list of successfully installed PV-systems might be provided as demonstration of competence.
However care should be taken that the organisation which installs the system gets the assurance of the manufacturer/supplier that the guarantees and after-sales service conditions are still valid when the system is installed by others.

If possible, training of the organisations' employees by the regional agent of the manufacturer/supplier is strongly recommended. Checking major Dutch manufacturers/suppliers on this point shows that one gives special training on installation, while the other trust in the instruction manual and will send replacements of defective components free of cost, once analysis has shown that the defect falls within the guarantee regulations.

When the system is tested after installation, the assistance of an independent party has proven most helpful in ensuring that the system functions according to the manufacturers' specifications. Such independent sources of expertise could be a university or technical high school department, which deals with renewable energy systems.

5. MONITORING OF PV-SYSTEMS

In each PV-system project a monitoring phase should be included. This monitoring of the system can be carried out by the development organisation or by the users. Preference should be given to the users: it will then directly provide a feed-back to the users themselves. The development organisation should stimulate the monitoring as it can derive useful data from it.

6. REFERENCES

• Oelert G./Auer F./Pertz K., Economic issues of renewable energy systems. A guide to project planning, GTZ, Eschborn, FR Germany, 1987.