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WATSAN COORDINATION MEETING UNICEF Kampala July 7,2005. SOLAR PUMPING SYSTEM. The solar system comprises: stationary or tracking solar array; controller; electric motor and pump The system pumps water with the use of power generated by the sunlight
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SOLAR PUMPING SYSTEM • The solar system comprises: stationary or tracking solar array; controller; electric motor and pump • The system pumps water with the use of power generated by the sunlight • Solar electric cells convert sunlight directly into DC power (photovoltaic process) • The controller converts the variable DC voltage into three phase voltage to run a brushless pump solar & motor diesel pumps appraisal COOPI
Aloi camp solar scheme solar & motor diesel pumps appraisal COOPI
DIESEL MOTOR DRIVEN PUMP • Diesel motor • Discharge and drive head (1) • Driveshaft (4) • Rotor/stator pumping element (6) solar & motor diesel pumps appraisal COOPI
Pabbo camp diesel motor solar & motor diesel pumps appraisal COOPI
Solar system Ideal for remote & unattended locations: No fuel & little or no maintenance No need of pump or motor attendants Solar pumping system are noise and pollution free Reliability and ease of use Diesel system Little maintenance of the pump Wide range of applications Capacity 10-1700 l/min Total head 15 – 450 m Ease of inspection & maintenance of motor drive head STRENGTHS solar & motor diesel pumps appraisal COOPI
Solar system High capital cost Restricted daily flow Limited storage capacity due to above Daily flow reduced with increase in total head Diesel system High O&M costs No operation due to shortage of fuel Power losses through drive head & shafting Greenhouse gas emission Human factor WEAKNESSES solar & motor diesel pumps appraisal COOPI
OPPORTUNITIES for both systems • To address the water demand of a large number of IDPs • To store water • To use tap stands with less effort for collecting water and reduced queueing time • To increase access to safe drinking water solar & motor diesel pumps appraisal COOPI
Solar system Lower flow rate due to rainy season Theft of solar modules Broken modules Disconnection of electrical wiring Diesel system Lack of maintenance Theft of fuel Unavailability of spare parts POTENTIAL THREATS solar & motor diesel pumps appraisal COOPI
Solar system Lower flow rate due to rainy season GPS Tracking Array Additional array oversizing (30%) Increased water storage Diesel system Lack of maintenance Keeping a service book Check of service book Theft of fuel Limited storage & proper planning of delivery Steps towards solution solar & motor diesel pumps appraisal COOPI
Theft of solar modules Solar array placed on high stand and connected with large size bolts Broken panels Solar assembly metal backed. No grid is suggested Availability of spare parts Local authorized distributors and dealers Steps towards solution solar & motor diesel pumps appraisal COOPI
Disconnection of electrical wiring The wires are placed inside iron pipes Steps towards solution solar & motor diesel pumps appraisal COOPI
Aloi camp solar scheme(oversized solar array) solar & motor diesel pumps appraisal COOPI
Cost-Benefit Analysis • System’s daily flow of 40 m3 • System’s lifetime of 10 years • Benefit: revenue from water fees • Capital cost and Operation & Maintenance costs • Life-cycle costs and benefits are discounted to the present value using 10% discount rate solar & motor diesel pumps appraisal COOPI
O&M costs breakdown Diesel pump: Fuel consumption 1 l/h – Discharge rate 10 m3/h • Cost of diesel(216,000 USh/month) • Cost of lubricant (15% of fuel)(32,400 USh/month) • Wages of two pumps operators (150,000 USh/month) • Kit of spare parts for pump – over 3 years(gland packing, vee belts, drive shafting assy, rubber column stabilizer, final connecting shaft) (122,467 USh/year) • Engine service kit (2000 hours) (363,658 USh/year) solar & motor diesel pumps appraisal COOPI
O&M costs breakdown Solar pump: replacement of pump & controller after 5 years of service solar & motor diesel pumps appraisal COOPI
Conclusions • Solar system is sustainable and reliable: no fuel, no need of operator, pump and controller are maintenance-free • Solar system is cost-effective: 4 times the hand pump’s daily flow with negligible recurrent cost • Diesel system has high pumping & lift capacity: 3 times the solar system’s daily flow solar & motor diesel pumps appraisal COOPI
Conclusions • Over 10 years of service, unit output cost of diesel pump is higher than solar: 558 Euro against 368 Euro • For a better analysis of field data (i.e. maintenance), the appraisal should be extended over a longer period of service-time solar & motor diesel pumps appraisal COOPI
PUMP PERFORMANCEGrundfos: (HT=6 Kwh/m2 day 20° northern latitude) H(m)=30~Q(m3/day)=26 H=60~Q=16 H=80~Q=13 solar & motor diesel pumps appraisal COOPI
PUMP PERFORMANCEMono diesel pump mod. 620Pump speed 1200 rpmH=30~Q=3.55 H=60~Q=3,48 H=80~Q=3,3 solar & motor diesel pumps appraisal COOPI