OASYS – South Asia: Dundee Workshop 2011
Micro-hydro applications in rural areas
Dr Arthur Williams
Dept. of Electrical & Electronic Engineering
University of Nottingham, UK
1
Types of hydropower
Conventional hydropower usually uses a reservoir (Llyn Brianne, Wales: 4 MW) <10 MW is called “Small” hydro
Micro hydro is usually “Run-of-river”
Pico hydro in SE Asia (< 5kW)
(Las Juntas, Peru: 25 kW) 2 Where are the potential sites?
Hydropower usually uses the potential energy of water: mass flow × head × gravity
Good sites either have high head Or
high flow AKRSP, Pakistan
Many good sites in remote rural areas 3
Rural Electrification Options
Grid Connection • too expensive • unreliable, especially in mountainous areas Stand-alone options • rechargeable batteries • Solar Home Systems Mini-grid options Kushadevi - Nepal • diesel generators - site of a 3 kW Pico Hydro project • Pico Hydro 4 Rural Electrification Options
Minimum 2006 World 300-1000 W Lower Range Bank study: hydroPico Probable Range Off-grid 300 W Costs. Wind Higher Range
300 W hybrid 2002 study in PV-Wind
Kenya: Generator of Type
PH: 15 ¢ 50 - 300 W Solar PV PV: >$1
300-1000 W
Diesel Petrol or
0 10 20 30 40 50 60 70 80 Predicted Cost in 2010 (UScent/kWh) 5
Civil works for pico hydro
Simple intake structures Kathamba, Kenya Storage only for evening use in dry season
Minimal use of cement
For higher head schemes, Polyethylene or PVC pipe is easily available
and light to transport. Magdalena, Peru Magdalena, 6 Pico hydro turbine types
• For higher heads: locally manufactured Pelton turbine
For medium heads: crossflow or pump as turbine - imported or locally made - also uses induction motor as generator Thailand: project of Border Green Energy7
Pico hydro turbine types
• For low heads: propeller turbine (with scroll casing or
open flume) Leverhulme Project, Nott’m Trent University Trent Nott’m Project, Leverhulme
Kathmandu University 8 Village hydro cost breakdown
Relative Cost 4% Civil works 8% 24% Penstock
Turbine,Gen.+Control 22% 4% Cable+Lamps
Wiring labour
Design+Management
38%
Average % costs for Kenyan schemes (2001) Note: No battery costs 9
Balancing costs and efficiency
Max. Voltage Drop 5% 10%
Cable Cost £2,000 £1,600
Power delivered to 0.97 kW 0.94 kW Consumers Total Scheme Cost £5,000 £4,600 (1 kW scheme) Cost per power £5,155/kW £4,894/kW delivered (-5%)
Reducing cable thickness saves on cost/kW - but there is a limit to acceptable volt drop (ΔV) 10 5 7Z 9 6Z 8Z 9Z 5Z 4 4Z A typical village layout Bb 11C (Kathamba, Kenya). 10C 12Z 8 16Z 10 Most spurs have several 13Z 14Z 15Z 19Z 3 17Z 18Z branches 3Z
2Z Spur A 2 Intake 22Z 7 Bc Houses are clustered. 1Z Penstock 20Z 23Z 5 24Z 60Z 6 25Z 21Z Load limiters used. 58Z Turbine 59Z Ba 26Z 27Z 4 57Z Spur B 28Z House T u rb in e h o u s e 30Z 29Z 31Z 1 54Z 3 12 32Z Bd 2 49Z 51Z 34Z 50Z 53Z Be 11 3 33Z 52Z Spur C 48Z
46Z 6 Ca 45Z 35Z 44Z 5 42Z 36Z 37Z 4 43Z Cb 38Z 7
41Z
40Z 8 39Z Cc
ViPOR program applied to Kathamba layout
5 7Z 9 6Z No cable across valley 8Z 9Z 5Z 4 4Z Bb 11C 10C 12Z 8 16Z 10 13Z14Z15Z 19Z
17Z18Z 3 3Z
M u k e n g e ria R iv e r Spur A 2 2Z 22Z7 Bc 20Z 1Z 23Z 5 24Z 60Z 25Z 21Z 58Z 6 59Z Ba 26Z 27Z 4 57Z Spur B 28Z T u rb in e h o u s e 30Z 29Z 31Z 1 54Z 3 12 32Z Bd 2 49Z 51Z 34Z 50Z 53Z Be 11 3 33Z 52Z Spur C 48Z
46Z 6 Ca 45Z 35Z 44Z 100 metres 5 42Z 36Z 37Z 4 43Z Cb 38Z7
41Z
40Z 8 39Z Cc Cable selection program (v.2) (under development)
Spurs and branches; Accurate positioning; Variable loads. 13
Off-grid schemes in rural areas are increasing
Growth in rural households accessing electricity in Sri Mini-grid schemes Lanka. can be connected to a grid extension.
14 LED lamps: an alternative?
“Hurricane” lamp – 800W (based on rate of kerosene consumption!) Same lumens as a 2W LED!
LED colour balance can be improved by mixing 15
Conclusions - lighting
LED v CFL
Photo Source: LUTW Low power; wide beam; higher efficacy; long life; V. low power; narrow beam; v. long life; Better for mains voltages. Efficient for LV systems 16 Dissemination
Support for local entrepreneurs: Management models, Peru Local manufacture of turbines. Photo: Phil Maher, Pico Energy Ltd.
Practical Action have useful publications 17
On-line information for Pico Hydro @ www.picohydro.org.uk www.pumpsasturbines.org.uk
Navigation
Home Page Downloadable Publications Pico Hydro Pico Hydro for Village Power - Design and Installation Manual What's New Pico Power Pack Download - A Practical Guide to Design and Manufacture Publications Water Power for a Village Business Newsletter Pico Hidro - Potencia para Aldeas Inquiries (Un Versión Español). Case Studies in Kenya & Nepal 18
Conclusions
• Village-based mini-grids are suitable for rural electrification • Renewable energy based systems are cost-effective (esp. hydro) • Costs can be reduced through: 1. local manufacture 2. using PC-based design for turbines, pipes and distribution cables Compared with kerosene lamps or dry-cell torches, Electric lighting is • Cheaper
Photo Source: LUTW • Cleaner • Safer
December 2010: Zhiture , one of two new Micro- hydro plants installed by AKRSP in Chitral, Pakistan.19
Extra slides: 1. Water flow variation
Flow available will vary with seasons and from year to year. Available flow is shown by a Flow duration curve flow duration curve. 6 5
Qav is (rainfall - evaporation) 4 × catchment area. 3 Q/Qav 2 Without storage, a 1 hydropower plant will be 0 sized to use a flow rate < Qav. 0 0.2 0.4 0.6 0.8 1 Probability 20 2. Low Head Turbine Project (2004-7)
Laser used for velocity measurements in a 200W turbine CFD, lab and field testing Conclusions: - Good efficiency if - the turbine is designed to minimise losses the turbine is designed to match the site flow (blade angles are more important than blade cross- section) air entrainment is avoided Prototype 1 kW propeller
4 kW 21 prototype
Pico hydro electrical system
Induction Generator
Excitation Capacitors
Induction Generator Controller
User Loads Ballast Load (+ battery charger) (heater)
• The IGC can be locally made • “Load limiters” can be used to prevent overloading
22 3. Costs of Solar Home System
Assume 5 hours peak sun/day Output is 500 Wh per day. 3,650 kWh over 20 years Cost: $4,200/3650 = $1.15/kWh
Data from: BuildAfrica.com23
4. Lighting: LED-halogen comparison
10000 3000 "superbright" 12V LED 1000 500 20W 12V Halogen
100
E E (lux) at 500 mm 10
1 -100.0 0.0 100.0 200.0 300.0 400.0 500.0 distance from peak along plane (mm)
A 1.5 W LED cluster claims to be “equivalent” to a 20 W halogen lamp! Powering a 12V LED lamp through a mains transformer can half the efficiency.24