Presentation on theme: "Technologies that Empower Distributed Generation for Rural Electrification: Options for Myanmar Yangon, Myanmar Dr. Chris Greacen September 5, 2013."— Presentation transcript:
Technologies that Empower Distributed Generation for Rural Electrification: Options for Myanmar Yangon, Myanmar Dr. Chris Greacen September 5, 2013
Outline Mini-grids and conventional grid extension –What happens when the grid arrives? Low cost pre-electrification (solar micro- grid) Lowering distribution cost for low-density rural electrification (SWER) Technologies to help spread out peak loads on mini-grids (MCBs, Gridshare) 2
Electricity for whom? 3
Large Plants Customers Small Power Producer Mini- Grid Customers Extending the grid and rural mini-grids National Grid 4
What to do when the big grid expands to reach the little grid? Option 1: formerly off-grid generators connect to the grid to sell electricity –DC sources (e.g. solar) Grid-connect inverter required –AC generators (e.g. hydro) Digital relay required Chris Greacen, Richard Engel, and Thomas Quetchenbach, A Guidebook on Grid Interconnection and Island Operation of Mini- Grid Power Systems Up to 200 kW (Schatz Energy Research Center and Palang Thai, LBNL E).
What to do when the big grid expands to reach the little grid? Option 2: purchase electricity from national grid for distribution on mini-grid. –Mini-grid must be built to acceptable standards
What to do when the big grid expands to reach the little grid? Option 1 + 2: both!
Mae Kam Pong, Chiang Mai, Thailand Built by government & community 40 kW Used to be off-grid; Making arrangements to sell electricity to grid
4 MW hydro - Tanzania electricity to 4000 households in >15 villages & sells to the grid
Affordable pre-electrification Pre-electrification is: –safe lighting –cell phone charging –small appliances Pre-electrification is generally not: –Agricultural milling –Power tools (electric saws, etc.) –Water pumping 14
Pre-electrification solar micro-grid Devergy in Tanzania
Devergy Every household that wants electricity gets an electronic pre-paid meter Electricity paid with cell phone About $7 per month
Devergy pre-electrification technology Every 5-6 households served by an Enbox 60 watts of PV 24 volt, 20 Amp-hr battery ZigBee wireless electronics, networked to metered households and other Enboxes The micro-grid sends update on status of all meters, voltage & current of all Enboxes via cell-phone (GPRS) carrier to internet every 5 minutes.
Single Wire Earth Return (SWER) Single wire system using ground as return conductor It is used for low cost rural electrification 18 Source: Tulloch & Davies, SWER: New Zealand & Australian Experience /SWERIan.ppt /SWERIan.ppt
How it all started Lloyd Mandeno invented SWER in New Zealand in Seen in 1940s as preferred solution for remote, sparsely populated areas. 200,000 km of SWER now in NZ and Australia. Successfully used in NZ, Australia, Canada, India, Brazil, Africa and Asia for sparsely populated areas Source: Tulloch & Davies, SWER: New Zealand & Australian Experience /SWERIan.ppt /SWERIan.ppt
How does it work? Resistance R1 = R (conductor) + R (earth return path) Allow 0.05 ohms/km at 50 Hz for earth return path. Source: Armstrong. Single Wire Earth Return
Advantages of SWER Cost Reduction –One conductor, less pole top equipment –Long, hilltop to hilltop spans –Fewer switching and protection devices –In Australia & NZ: Capital cost 50% less than 2-wire, single-phase 70% less than 3-wire, 3 phase Design Simplicity Reduced maintenance costs Estimated 50% maintenance cost saving Reduced bushfire hazard – avoid conductor clashing Source: Armstrong Single Wire Earth Return 21
22 Limitations of SWER Restricted load capacity Requirement for reliable low resistance earthing at isolating and distribution transformers Possible interference with metallic communications systems Higher losses due to charging currents Source: Tulloch & Davies, SWER: New Zealand & Australian Experience /SWERIan.ppt /SWERIan.ppt
Technologies to help reduce peak loads on micro-hydro mini-grids 23 Voltage drops
Miniature Circuit Breakers (MCBs) or PTCs to limit peak loads Mini-circuit breaker Mini-circuit breaker can encourage peak load reduction kWh meter
25 C ASE S TUDY - L OAD MANAGEMENT Source: Schatz Energy Research Center Voltage drops A 35 kW micro-hydro plant in Rukubji, Bhutan Lighting, TVs, rice cookers and water boilers are the common loads As on many mini-grids, when load exceeded generation capacity, brownouts occurred
26 G RID S HARE L OAD M ANAGEMENT T ECHNOLOGY Humboldt State University team, in partnership with Bhutan Power Corporation and Bhutan DOE developed the GridShare. The GridShare, installed in each household, limits household load only during a brownout or voltage drop. The device is intelligent enough to detect rice cookers, and keeps them turned on for people to finish cooking their rice.
27 G RID S HARE L OAD M ANAGEMENT T ECHNOLOGY Reduced spoiled rice and Residents stated: the grid is more predictable Electrical data indicated a reduction of over 90% in severe brownouts
Conclusions TechnologyApplicationImpact Interconnection relaysmini-grid connect to main-grid Lowers risk to developers of isolated mini-grids Solar pico-gridAffordable pre- electrification deliver small amounts of electricity, deploy quickly, inexpensively ZigBee & GPRS internet connecctivity monitoring of remote mini-grids Lowers repair costs by catching problems early on. SWERLow cost grid extensionReduced hardware cost MCBs and GridShareManagement of peak loads Fewer brownouts