Solar Energy Programme

Demonstration of Solar photovoltaic Pumping (SPV) for safe drinking water supply in remote rural area of Bangladesh ( UNDP supported)

Background :

There is scarcity of safe drinking water in rural areas of Bangladesh. The Problem becomes very acute during the dry season, when water table goes down and most of the earthen well dried-up. However, there is abundance solar irradiation all over in Bangladesh. So, Solar photovoltaic water pumping system could be a suitable solution to supply safe drinking water in off grid areas. Though the upfront cost of SPV pumping is high, but it needs very low maintenance.

Barind is the most arid region in the country. Normally village women collect drinking water from dug-well. Sometimes they had to pull water from 40 to 50 m depth. Most of their time and energy was spent to collect drinking water.

Sustainable rural energy addressed this intervention by installing four submersible solar water pumps at the four villages in Barind region. Total Installation cost of the system was Tk 29 lacs. Water is stored in over head reservoirs. Capacity of each reservoir is 10,000 liter. The beneficiaries are now enjoying the same facility as Municipal water supply. The project was handed over to Barind Multipurpose Development Authority (BMDA).

SPV pumping system

A pump operated by solar energy is called Solar Photovoltaic pump (SPV). This is one of the most reliable technologies for pumping water from boreholes, rivers, lakes, shallow wells, and canals.

SPV array at Sheetal Danga

A SPV water pumping system consists of a photovoltaic array, motor pump and a power conditioning equipment (optional). The pumping system can be surface or submersible type and the motor can be either AC or DC. Submersible pump is installed in the bore hole. This unit works on AC power. An inverter is connected to convert DC power of SPV array into three face AC power.

SPV pump provides high water demand during long, dry summer day. Water can be pumped during the day and can be stored by a storage tank. Water is then available at night and during cloudy periods. The possibility of storing water eliminates need for batteries in the system. Indeed this is cost effective to store water in a tank rather than storing power in a Battery bank. To get higher solar insulation and maximum benefit from the system manual tracking have been introduced. PV module also covered with an angle bar to protect against theft.

System Components :

Submersible AC pump.
Solar PV Module.
Array junction box.
Power maxi miser.
Installation Accessories.
Cables and other hard ware.
Supply and delivery pipe.

Information about 1800 wP System :

Submersible SPV pump

Model : Tata BP SP 5 A 7Y (1800wP)
Moto pump set : Grundfos 0.75HP
Country of Origin : Denmark
Capacity : 0.75 Hp
Array Capacity : 1200wP
Total Dynamic Head(TDH) : 50M
Water lifting per day : 35,000Liters ( assuming peak sunshine at 5.5 hrs/day and 3 times manual tracking )
Overhead Pipe = 3" Dia and 35 feet depth from ground
Total Original boring depth = 128 ft
Pump depth = 121 ft

Solar Array

Solar PV Module : 75 wp , 12 V
Total module : 24
Array output : 115 V< Vdc< 175V Max, Short circuit current Isc= 14Amp DC

Information about 1200 wP System :

Submersible SPV pump

Model : Tata BP SP 5 A 7X (1200wP)
Moto pump set : Grundfos 0.75HP
Country of Origin : Denmark
Capacity : 0.75 Hp
Array Capacity : 1800wP
Water lifting per day : 35,000Liters ( assuming peak sunshine at 5.5 hrs/day and 3 times manual tracking )

Total Dynamic Head(TDH) : 50M

Overhead Pipe = 1.5" Dia and 35 feet depth from ground
Total boring depth = 97 ft
Pump depth = 92 ft

Solar Array

Solar PV Module : 75 wp , 12V
Total module : 16
Array output : 115 V< Vdc< 175V Max, Short circuit current Isc= 14Amp DC

Before intervention : Women had to pull water from 40 to 50 meter depth

After intervention : Remote areas water supply facility

Objectives of the project

To provide safe drinking water supply facility in the off-grid areas.
To substitute diesel pump by SPV pump.
To replicate this model for irrigation purpose.

Scheme Location & Installed Capacity :

Sl	Location	Array Capacity in Wp	Dynamic Head in meter	Water Lifting Capacity(Liter/day) three time manual tracking)	Installation Cost in lac Tk
1.	Village : Awal Para (Pukuria Para) Union : Nezampur, Upazila : Nachole District :Chapai Nawabganj	1800	50	26,000	7.3
2	Village : Sheetal Danga (Eco- Village) Union : Shironti Upazila : Shapahar District : Naogaon	1800	50	26,000	7.3
3	Village :Bondhu para ( Eco- Village), Union : Saor Upazila : Porsha District : Naogaon	1200	50	13,000	5.7
4.	Village : Saidpur (Eco- Village), Union : Nirmoil Upazila : Patnitala District : Naogaon	1200	50	13,000	5.7

Operation and Maintenance :

SPV pump requires very low maintenance. The solar panel is expected to provide about 20 years of satisfactory service under normal conditions, even though the cell itself may last much longer. The only maintenance requirement is the occasional washing of the PV surface to maintain maximum optical transmission through the glass. The panel has to be protected from breakage by external agencies. Some manufacturers cover the cell/array with tough glass. The motor and the pump require the usual periodic maintenance like cleaning, lubrication and replacement of worn parts. The SPV pumping units will be under contractor’s O & M for a period of two years from the date of commissioning. After the security period beneficiaries will be responsible for pump O & M.

Environmental Impact:

SPV pumping is an environmentally friendly technology. It reduces dependency on fossil fuel and eventually helps Green House Gas abatement.

Conclusion and recommendations

Application of solar PV submersible water pumping has recently received increasing attention due to its various benefits such as low maintenance, longer life and reliable operation even at low insulation. Over 50,000 solar pumping systems are already at work around the world supplying water for people, livestock, irrigation and aquaculture (Mahmud, 1998).
In Bangladesh solar insulation is as high as 4.5 kwh/m²/day. Therefore irrigation and water supply in rural areas could be met by solar powered pumping system.
This system is suitable where there is no grid connection and water head is high and conventional tube well does not work.

Although this is more expensive than conventional diesel pump but due to scarcity of electricity low voltage and load shedding SPV pumping could be a popular option for irrigation and water supply.

NB: For further information please contact with BMDA project office at Rajshahi

Solar Energy Programme (UNDP Supported )

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