Solar PV water pumping study - FINAL REPORT ... - UNDP, Namibia

Feasibility Assessment for the Replacement of Diesel Pumps with Solar Pumps
FINAL REPORT: September 2006
The litres of diesel consumed per annum are calculated from the running time of the diesel
pump. A fuel cost escalation of 2% has been assumed but the fact remains that this is a
indeterminable parameter as it depends on oil reserves, conflict in oil producing countries
and exchange rate.
The transport cost of fuel to site is added to the operating cost of the diesel pump. It is
assumed that the average distance to the fuel supply infrastructure is at a 100km distance
(service distance) and that six trips for fuel are needed per year. The percentage cost
contribution towards the transport costs have been set at 20%. Therefore the other 80% of
the transport costs are carried by other activities attended to. The cost rate of the transport is
set to N$ 3/km at current fuel prices.
Oil consumption of the engine is provided for under the maintenance costs.
Private installation
It is assumed that the private diesel system has additional costs for driving to a diesel pump
which is away from the house (distance assumed is 3km). The transport cost to a remote
diesel pumping installation is therefore added to the operating cost of the diesel pump. The
interval of the cost is either every day or every second/third day, depending on the pumping
interval selected to get an optimal diesel pumping system.
It is assumed that a farmer will visit a PVP installation once a week at the same distance of
3km. This is the only operating costs assumed for a PVP installation.
DRWS installation
There is no additional cost for a “remotely-from-community-located” diesel pump as it is
assumed that this is not generally the case, i.e. the pumping system is located in the vicinity
of the community.
Refer to Appendix A2 for details.
3.1.4.3 Maintenance and replacement costs
The maintenance and replacement of the pumping systems is applicable to both the PVP
and diesel pumps. The maintenance schedule and details are dependent on the technology
employed. The replacement schedule is dependent on the ruggedness of the system, acts of
God (e.g. lightning), the operating environment (water quality, diesel quality, direct exposure
to sunlight, excessive temperature etc) as well as the level of maintenance performed.
PV pumps
PVPs require skilled personnel to carry out the service and this will in most cases mean that
the unit to be serviced needs to be shipped to Windhoek. The costs stipulated in the costing
analysis are based on product specific parts and include labour as well as a transport fee.
The service interval depends on the pump systems used. In most cases the service interval
is 5 years. However the service interval for the Watermax is once a year while the Lorentz
pump is every three years. Service intervals are also highly dependent on water quality and
depth of installation. It is assumed that all main components in a PVP excluding the solar
modules will have to be replaced within certain intervals. Refer to Table 3.3.
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