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The fundamentals of recent power outages across the country

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The Africa Centre for Energy Policy (ACEP) has observed, with great concern, the severe power outages that have occurred over the past three days across the country, and the impacts on business operations and general comfort of the people of Ghana.

This incident has occurred barely within two weeks after Power Distribution Services Ghana Ltd. (PDS) took over the management of Ghana’s power distribution subsector from the Electricity Company of Ghana (ECG), with the fundamental objectives to increase reliability, access and efficiency of power.

It is therefore not surprising that many Ghanaians, having high expectations of PDS’ presence, have apportioned blame to PDS for the current blackout. As an independent think tank in the energy space, ACEP sees the need to promote public understanding of the fundamental causes of the situation; hence this statement. In this statement, we explain the on-grid power sector value chain and how technical hitches in the transmission chain has resulted in the power outages Ghanaians are currently experiencing.

 

1. Ghana’s on-grid power sector value chain Ghana’s power sector value chain consists of power generation, power transmission, and power distribution as shown in the infographic below: 2 Once power is generated by the power producers, GRIDCo transmits this power to its bulk customers including ECG and NEDCO. Unlike in the past when ECG distributed power directly to consumers, ECG currently serves as a bulk supplier to Power Distribution Services (PDS) Ghana Ltd for onward distribution to consumers (homes, factories, businesses etc.). From the infographic, technical and/or non-technical challenges at any point along the power supply value chain limits electricity supply to the final consumer.

2. Causes of recent power outages The fundamental cause of the blackout is the ongoing construction of the road interchange at Pokuase, which has necessitated the diversion of GRIDCo’s 330kV transmission line towers that runs from Tema to Aboadze in that vicinity. This requires taking an outage of the entire line to undertake the diversion. The following are the effects of the ongoing construction at Pokuase and the associated diversion works: a. Tripping of existing transmission lines: As a result of the outage on the 330kV line, no power was transmitted on the Aboadze to Accra i.e. from west to east. Instead, power has had to be transmitted from Akosombo through Mallam, Winneba and Cape Coast to the Western part of the country through the 161kV transmission line.

 

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These 161kV lines become overloaded, thereby causing it to trip as a protective measure to avoid any major damage to equipment. It is important to note, however, that the transmission lines across the country are interconnected to the extent that disruption in one transmission line has a rippling effect on others. b. Tripping of generating units: Power plants are designed to automatically shut down in response to hiccups in the course of power transmission as seen in case (a) above. This is a protective measure to prevent power from flowing back to the generators. It has therefore become necessary to temporarily shift and limit power flow through the coastal corridor to facilitate stability of the entire transmission network whiles work is completed on the diversion of the line at Pokuase. This issue is thus a pure operational and technical challenge at the transmission stage; it has nothing to do with technical faults at the generation or distribution stage of the power value chain. What next? ACEP’s checks reveal that the ongoing relocation of GRIDCo’s 330kV line at Pokuase is expected to be completed early next week, by which time we hope that power transmission and distribution will return to normalcy.

Recommendations

1. GRIDCo, and for that matter every power utility, must inform Ghanaians well ahead of time about hiccups in the system so as to prevent the kind of confusion and public agitation we see now. Timely announcement will help consumers plan their lives and businesses.

 

2. It is important that GRIDCo continues to invest in high capacity transmission lines to create sufficient redundancies to avoid overload of transmission lines to the point of tripping. To achieve this, GRIDCo must have a strong financial base. This means that PDS and NEDCO and all players within the power value chain must pay the full cost of power they take from their suppliers. Particularly, efficiency on the part of PDS and NEDCO is also required to address technical and commercial losses along the distribution chain.

3. Distribution companies (PDS and NEDCO) should invest in buffer infrastructure at the distribution end so as to sustain and smoothen power supply to consumers in times of hitches along upstream power value chain.

Signed

 

Benjamin Boakye

Executive Director

 

 

Source: myjoyonline

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