Pedal Power Pack and Rural Energy Security
2002 USD $190 35kg including 40 Ah 12V automotive battery. One person generates 84 - 120 W. Two people generates 225 - 240 W more easily. Also White LED and solar details. Capex less than solar. Opex acceptable only for emergency use. Genset slightly higher minimum capex (but lower per watt) and much higher opex for fuel? Essentially issue is scalability relative cost of fuel (including transport).
PEDAL POWER PACK AND RURAL ENERGY SECURITY
1. The Problem.
In Nepal even in the 21st Century about 95% of the rural population do not have electric home lighting system. Their productive day ends when the Sun goes down. Each evening millions of families retreat into smoky rooms lit only by kerosene lamps or wood fire. The lot of this vast proportion of Nepalese population could be improved by the provision of a resource, so many elsewhere take for granted. That resource is simply electricity. The rural as well as urban poor people want and need electricity for their daily activities. But they do not have at present enough money to buy the source of energy, whether it is based on micro-hydro or solar PV or wind technology. How they get it is going to be one of the most critical developmental and environmental issues of this century. Could they seek even a modest rise in their quality of life and enjoy their fundamental citizen's right to electricity?
2. The Solution
To solve this problem Centre for Renewable Energy (CRE), Kathmandu has undertaken on adaptive research for design and development of a portable Pedal Power Pack (PPP) under RETs – in Asia Project funded by the Swedish International Development Cooperation Agency (SIDA) and coordinated by the Asian Institute of Technology (AIT), Bangkok.
In order to better understand this problem let us simply analyse the general daily requirements of electrical power for the rural community under various scenarios of rural electrical lighting.
2.1. Typical Daily Power Consumptions of Lamps and TV under Rural Usage.
a) One White LED lamp type "TUKIMARA" fitted with 3 pcs. of 5mm j White LEDs.
Daily Power Requirement @ 3.6V DC x 0.120 Amp/lamp x 3.5 lighting hours per day = 0.437 mW/lamp x 3.5 hr./day = 1.52W/lamp/day
b) One 12V DC TL/CFL Lamp as used in solar home systems in Nepal.
Daily Power Requirement @ 12V x 1 Amp/lamp x 3.5 lighting hours/day
= 12 Watt/lamp x 3.5 hours/day = 42 Watt-hour/TL Lamp/day.
C) One 14 inch Black and White TV
Daily Power Requirement @ 20 Watt/TV x 3.0 hours of TV show/day
= 60 Watt-hour/TV/day
2.2. Scenario of Daily Rural Operation of Lights and TV
(A) One Black and White TV + 2 Nos. of CFL or TL Lamp
Daily Power Requirement:
1 x 60+2 x 42= 144 Watt-hour/day
In a 12V DC system the current requirement in this case will be simply
144/12= 12 Amp-hr.
Any low-cost appropriate technology device, such as the above mentioned PPP that could manually generate 10 amperes at 12V DC should provide 12 Amp.-hr. in about 1.25 to 2.25 hours during its pedaling operation, depending upon the condition of storage battery and nature of the pedaling person. This is at all not a difficult task to accomplish in our rural context. It is to be duly noted that this time period of operation (i.e. 1.25 to 1.75 hours) need not be continuous. It could be an intermittent mode of operation during the daily time period from
5 A. M. to 7 P. M. It could be also performed by an individual or by the individual members of family, singly or jointly, in rotation and at their convenient times.
(B) One Black and White TV and 1 No. of TL/CFL Lamp and 3 Nos. of
"TUKIMARA" White LED Lamp
Daily Power Requirement:-
1 x 60+1 x 42+3 x 1.52 =60+42+4.56
= 106.56 Watt-hr./day; say 107 Watt-hr./day
In a 12V DC system this would require 8.88 Amp.-hr./day; say 9 Amp.-hr./day
This type of PPP should provide this much energy in about 1 to 1.5 hours of operation.
(C) 3 Nos. of CFL/TL Solar Lamps.
Daily Power Requirement:-
3 x 42 = 126 Watt-hour/day
In a 12V DC system this would require 10.5 Amp.-hr./day; say 11 Amp.-hr./day
This type of PPP should provide this much energy in about 1.25 to 1.50 hours of operation.
(D) 1 No. of CFL/TL Solar Lamp plus 3 Nos. of "TUKIMARA" White LED
Lamps
Daily Power Requirement:-
1 x42+3 x 1.52= 42+4.56 = 46.56 Watt-hr./day; say 47 Watt-hr./day.
In a 12V DC system this would require 3.91 Amp.-hr./day; say 4 Amp-hr./day
This type of PPP should provide this amount of energy in about 0.5 to 0.75 hours of operation.
(E) One Black and White TV and 3 Nos. of "TUKIMARA" White LED Lamp.
Daily Power Requirement:-
1 x 60+3 x 1.52 = 60+4.56 = 64.56 Watt-hr./day
In a 12V DC system this would need 5.38 Amp.-hr./day; say 6 Amp.-hr./day.
This type of PPP should generate this amount of energy in about 40 to 55 minutes.
(F) 4 Nos. of TUKIMARA White LED lamp.
Daily Power Requirement:-
4 x 1.52=4.64 Watt-hr./day.
In a 12V DC system this would require 0.50 Amp-hr./day; say 0.5 Amp-hr./day
This type of PPP should deliver this amount of energy in about 5 to 7 minutes of operation.
In other words PPP could be run, depending upon the extension of daily lighting hours and the condition of rechargeable batteries, for approx. 30 minutes once in every 5th or 6th day of the previous recharging. This also meaningfully indicates that one such PPP should be enough to provide electrical energy to provide White LED illuminations to at least 100 households in a village, each household using 4 Nos. of TUKIMARA type White LED lamps at the rate of 3.5 hours a day; and of course one PPP being commonly owned by the 100 village households.
3. Portable Pedal Power Pack.
To provide power for charging various type of rechargeable batteries, specially for the use of the poors or "have-nots" in rural conditions a simple portable Pedal Operated Power Pack (PPP) was recently designed and developed by CRE. The pedal power pack, costing approx. Rs. 15,000*[1] (i.e US$ 190 only), basically consists of the following components.
a) A metallic frame incorporating a specially designed pedaling system fitted with return springs.
b) A single groove V-belt type cast iron flywheel mounted on a bicycle axle with free wheel and supported by a bicycle yoke fitted on the metallic frame.
c) A 12V alternator, regulator and automotive lead acid battery (as generally used in cars and vehicles) and driven by the cast iron flywheel.
When the pedal is pressed down by the leg, it causes the flywheel to revolve fast; and then the V-belt drives the alternator at a higher rpm. When the leg is removed from the pedal, the return springs quickly bring the pedal to its original position. The bicycle free wheel fitted on the supporting shaft allows the flywheel and the alternator to revolve in only one direction. Only the downward travel of the pedal is its power-stroke. The total weight of the PPP including 40 Amp. hr. capacity automotive battery is less than 35 kgs. For ease of transportation in hilly areas the machine could be easily dismantled into pieces by loosening the relevant nuts and bolts.
4. Technical Parameters.
The salient technical features of this PPP are they as follows:-
- Overall dimensions:
Length x Width x Height : 1,285mm x 775mm x 1, 300mm
- Diameter of Single Groove Flywheel : 590mm
c. Height of the centre of Flywheel : 1,000mm
d. Centre distance between
flywheel and alternator : 730mm
e. Height of hand-rest : 990mm
f. Speed Multiplying Ratio : Approx. 8.4 times
g. Dimension of pedal platform : 1,065mm x 415mm
h. Alternator : 12V Automotive type, capacity
approx. 40 amperes
i. Regulator : BOSCH, Germany 12V to match
the above alternator
j. Driving Belt : Dunlop type A- 100/2576
single V-belt.
k. Storage Battery : BOLIDEN brand 40 amp-hour
automotive battery
l. Maximum weight with battery : 35 kg.
Some photographs of this Portable Power Pack are given below for better understanding and evaluation of this low cost device (See Photo Nos. 1, 2, 3, 4, 5 and 6)
5. Workshop Test of PPP.
This portable Pedal Power Pack was tested many times in the machine shop of Balaju Technical Training Centre, Balaju, Kathmandu. When operated by a single person it could easily generate 7 to 10 amperes of DC charging current. When operated jointly by two persons , it was found to be more comfortable for operation. It could then easily produce upto 15 to 20 amperes of battery charging current. In this way it is somehow equivalent to a solar PV power pack of 200Wp to 400Wp. Its total assembly cost including the battery is around US$ 190.00 only; which is a very attractive figure for those persons who can not afford to own even a 40Wp SHS costing around US$ 360.00.
For comparison, a 40Wp solar PV module in common Nepalese context daily generates about 9 to 10 Amp-hr. of 12V DC current, which is stored in the solar batteries for use in the evening hours for generally lighting 3 Nos. of 10 watt capacity solar lamps. With this PPP a single person could easily generate 10 Amp-hr. of electrical energy in about 1.5 to 2.0 hours of pedaling. When operated by two persons jointly this amount could be easily generated in about 30 to 45 minutes.
6. Multipurpose Applications.
i) This PPP is a good substitute of solar PV modules for powering of storage batteries of Solar Home Systems or of White LED Lamps; which obviously provides some sort of energy security at the village community level.
ii) Villagers could now enjoy TVs (colour or black and white), CD-players, cassette players, radios, etc., as their source of electrical power (i.e., storage type lead-acid batteries) could be daily charged by the PPP as required and at any time of the day and evening hours, continuously or intermittently, by a single person or a group of person in rotation.
iii) In earthquake hits areas or areas devastated by the floods or landslides such PPP sets could be of great help to provide power for communication and lighting purposes during immediate disaster mitigation and relief works.
iv) Such PPP could be used to charge batteries of rural telecommunication system.
v) Such PPP could be easily used in village level in various income generating activities as mentioned below:-
a) Powering of computers and printers.
b) Powering pf photocopying machines.
c) Powering of Fax machines.
d) Charging of storage and rechargeable batteries of village users.
e) Powering of village level photo-studios.
f) Powering of water purifying machines using UV disinfection technology
g) Providing lights during night hours in broiler poultry farms.
h) Powering small 12 or 24V DC type water pumpsets to lift water for use in drip irrigation systems used in vegetable farmings
i) Conducting adult-education or coaching classes in evening hours.
j) Running of medical care units in villages in evening hours.
k) Conducting art/painting works during evening hours.
l) Weaving and sewing works during evening hours.
In the above mentioned applications, where necessary, suitable inverters (type 12/24V DC to 220V AC) should be used; which are assembled and easily available in the local market.
7. Use by Urban Poor
Pedal Power Pack could also be used by urban poors for home lighting/TV purposes, specially with White LED lamps and also for some of the income generating activities as mentioned above.
8. Common Use of Portable Power Pack
In case of the financial constraint or if desired by the stakeholders, four or five nearby users could buy one such PPP for common use. Each user should operate the PPP for two hours a day at maximum; time of operation being decided as mutually agreed upon. Such arrangements should substantially lower the purchase cost borne by each user, and allow them to have electric home lighting system and TV-hours at a nominal initial cost.
9. Conclusion.
Portable Pedal Power Pack developed by CRE is certainly a recent sensible technical breakthrough in the search for on Appropriate Technology for Sustainable Development. This simple and innovative device could easily provide necessary electrical energy at a low cost, which is affordable even to the poor section of the rural society not only in Nepal, but also in many developing countries of the Third World. Moreover, further R & D works should be undertaken to improve its performance/design and to reduce its initial cost; as it has a big potential to contribute towards the improvement of the quality of life of the rural poors and to some extent to help them to create income generating activities in rural society.
For further information, please contact:-
Centre for Renewable Energy
Ga-2/717, Bag Bazar
(Near Hotel Ganapati, Bag Bazar)
P.O. Box 589,Kathmandu, Nepal
Phone No. +977-1-248852/351052, e-mail: < cre@ccsl.com.np >
OUR CONCERN IS RENEWABLE ENERGY, ENERGY CONVERSATION AND SUSTAINABLE DEVELOPMENT.
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