SWS and Electrification Lessons from Ghana’s Experience. By: Jabesh Amissah-Arthur, Managing Partner,

Presentation Outline  Electrification in Ghana. Starting Conditions. Accomplishments.  Innovating for Rural Electrification. Background and Motivation for SWS. The Shield Wire Scheme (SWS) – Description Benefits and Savings of SWS. Cost Comparison with standard MV supply. Operational Comparison with standard MV supply.  Conclusion. Successes and Failures. Lessons.

Starting Conditions  The grid supplies only 240 towns in 1/3 rd of Ghana.  Virtually all isolated diesels are non-operational.  Macro-economic indices far from being favourable. 5yrs of economic decline. 3yrs of drought, Project area considered to be very poor.  Project viability doubtful !  Starting conditions were simply far from ideal.

Accomplishments  1985: Grid covers only 1/3 rd of Ghana’s land area. Access to service = 23%.  1990: Nine regional capitals and 400 towns have supply from grid.  1995: 1,000 towns (including 87 of 110 district capitals) have grid supply.  2000: All districts and towns have grid supply. Access = 43.7%.  2005: 3,200 towns to have supply. Access = 50+%

Innovating for Rural Electrification: Background & Motivation for SWS  The citizens of small communities living near HV transmission lines who had no supply made it a Corporate Social Responsibility and Public Relations issue for the utility, Volta River Authority (VRA).  VRA invited Prof. Iliceto in early 1980s to make innovative proposals for a “Low Cost” solution to serve the settlements near its 161kV transmission lines.  Shield Wire Scheme (SWS) is proposed & implemented: SWS is serving more than 10,000 households in 30 communities that may not otherwise have been served. The cost of SWS is only a fraction of standard MV line. The operational performance of the SWS in terms of outage frequency and time is better than normal.

The Shield Wire Scheme (SWS)  The SWS uses the sky/shield-wire which is normally grounded with no voltage and only shields the power lines below.  The sky/shield-wire in this case is: Insulated for medium voltage operation. Energised at 20-34kV from sub-station. Supplies loads using earth return current.  Still performs power line protection.  No additional environmental impact.

The Shield Wire Scheme (SWS)

Savings and Benefits  Installation Costs are lower because: Common usage of conductors & grounding rods. Does not add to the power line right-of-way.  Operational Performance is better as: Outage rates are low & permanent faults are rare. Low medium voltage losses due to conductor size. Maintenance burden is extremely low.  Other Benefits. Community protection of the transmission line.

Cost Comparison: MV vrs SWS

Comparison of Operational Performance Total Outage Frequency - Standard MV vrs SWS.

Successes and Failures  The massive extension of the HV grid presented an opportunity to deploy SWS on the new lines.  SWS cost is only 15% of equivalent MV line. Yet its operational performance is superior.  SWS is now proven technology which supplies settlements within a 20km corridor of the transmission line at very reasonable cost.  A subsidised connection charge helped many to receive supply initially. But paying the bills to maintain supply has been difficult for some.  In more than a few villages, only the Chief’s Palace has been able to retain supply.

Lessons  SWS is well-suited for medium sized communities (ie total <10MW) located near transmission lines.  When planning electrification for poor communities we need to recognise two affordability thresholds: A.Those who can at least afford the variable (operating) cost of supply but not the full capital recovery burden. B.Those who cannot afford even the operating cost alone.  Electrification for Group A is sustainable with only an initial connection subsidy which may be justified on social & poverty alleviation considerations.  Access for Group B requires perennial subsidy and so needs cautious consideration of the source of subsidy else “true access” may not be sustainable.

The End Lessons from GHANA’s experiences. Jabesh Amissah-Arthur