PUBLIC ANNOUNCEMENT NAWEC informs the general public that the current electricity situation in the GBA is as a result of some maintenance being carried out on two engines in both Brikama and Kotu Power stations since on Monday 4th September, 2017. This has made it extremely difficult for NAWEC to distribute normal supply to all customers at the same time thus stretching the load shedding rooster. Consequently, it has led to the low pressure or lack of water being experienced in the water supply system. NAWEC assures its esteemed customers that extra efforts will be made to keep the rest of the generators available during the period in order to minimize the load shedding as a result of the absence of the engines. NAWEC apologizes for any inconvenience this may cause and promises to restore normal supply as soon as works on the engines are completed. Thank you.

Transmission & Distribution System

The Transmission and Distribution System is gradually evolving and rehabilitation and expansion to ensure access and reliability is the priority of NAWEC. The basic problem within the Transmission and Distribution System remains the lack of adequate despatch capacity and over-aged network components.

Two 33 kV transmission lines with a total length of about 115 km convey electricity from Kotu to 33/11 kV substations. Lines at a voltage of 11 kV (total length 181 km) from the substations carry electricity to 11/0.4kV-transformer stations at various locations in the GBA and Brikama. Low voltage lines from the substations distribute electricity to three phase and single-phase consumers at 400V and 230V respectively.

Constraint exists in the medium-voltage network in adequately offloading the existing power to the grid. The salt-loaded air has substantially lowered the dielectric strength of the insulators and also affected mechanical strength of system hardware (insulators, clamps, conductors, etc).

The majority of the medium voltage feeders are not only overloaded but do contain sub-standard sections which restrict their transmission capacity. The most adverse consequence of these problems is that load shedding is inevitable even when there is sufficient generating capacity. During the load-shedding exercise, equipment and components will be operated which is not meant for such actions (fuses and fuse carriers are damaged, circuit breakers and sectionalises are being put under stress while their design is for a different operation). As a matter of inadequate switching facilities, load-shedding will place the operational staff at extreme risks. The implementation of the Venezuela project has started taking effects but more investment is still required.

Despite the numerous challenges faced, T&D continue to strive in the operations and maintenance of its assets.

Operations

In our quest to deliver efficient and reliable power supply to our customers, expansion and improvement works are ongoing. However, T&D is still faced with voltage problems in all its primary sub stations  The voltages received (ranging from 29kV to 31.5kV) are sometime difficult/or impossible to transform to the required 11kV resulting to very low voltages at the receiving ends.

In addition to the voltage problem it was difficult sometimes in the year to distribute equitably the available 23/17mw among the 356 connected distribution transformers (117145kVA).  These transformers, believed to consumed 4.21722mw of the available energy, couple with the 10% voltage drop on the 33kV line recorded at the primary substations not to mention the reactive component and other distribution losses subjected to the system.  These couple with the untouchables makes load shedding extremely difficult without opening the 11kV feeders.

Maintenance

Transmission and Distribution Division continues to maintain, upgrade, rehabilitate and execute a regular maintenance program to address the challenges.

Primary Substation

T&D continued to monitor the loads subjected to primary substations and ensuring load is equally distributed on all sub stations.

Projects

T&D continue to play a pivotal role in project implementation within and outside the Greater Banjul Areas (GBA). Key projects executed recently include Venezuelan Project, West Coast Region Electrification Project, Kabada Project, numerous small scale extensions, regular interventions etc.

Reinforcement of T&D Network (Venezuelan Project)

The network in some areas has been upgraded, rehabilitated and expanded on the existing Low Voltage Network in the Greater Banjul Area. The upgrading, rehabilitation and expansion of the network is ongoing and will significantly reduce losses. As part of the project, there was a substantial upgrading of the Pole Plant, Pole replacement, general upgrading amongst others.

Sub Regional Energy Integration

Under the umbrella of ECOWAS through the West African Power Pool (WAPP), efforts are ongoing to create the ECOWAS energy market through the interconnection of all ECOWAS member states to a single grid. Evidences have shown that it is a sustainable source of electricity for the sub-region. The Gambia is expected to be connected through the OMVG and low voltage cross-border interconnection.

OMVG Project

The project consists of the installation of two hydroelectric power generating stations, one in Sambangalou in Senegal with an installed capacity of 128MW and the other in Kaleta in Guinea, with an installed capacity of 228MW, as well as the construction of an interconnection between the electrical networks of the four countries of the OMVG, consisting of 1709 km of power transmission line in 225 kV, and 15 transforming sub-stations. The yearly energy that will be produced by Sambangalou is valued at this stage at 400 GWh/year. WAPP secretariat continues to support OMVG secretariat to source financing of this project. In 2011, Guinea opted to build the Kaleta on its own but reassured the member states in respecting the proposed interconnection and energy sharing.

Cross Border Interconnection

NAWEC continues to have an excellent partnership with SENELEC where even a memorandum of understanding exists since 2008. It is expected with support of WAPP, interconnection is feasible in the near future at the LV level (33KV) for the benefit of both countries.

Challenges

·         Old distribution network resulting to high network losses

·         Transmission not separated from distribution resulting to a weak system

·         Power generation at the same voltage level to transmission and distribution resulting to serious system instability

·         In adequate heavy duty equipment and maintenance materials for operation and maintenance of the T&D due to cash flow problems

 

Way forward

·         Replacement of old network lines.

·     Construction of an upgraded transmission line ie 33kv to 132 kv with a dispatch centre linking the load canters. A proposal has already been developed for funding and BADEA has agreed to fund the feasibility study.

·         Provision of heavy duty equipment through bilateral or concession loans through government.

Health & Safety


     Contact Us

     53 Mamadi Maniyang  Highway
     Kanifing, K.M.C. 
     P.O.Box 609, Banjul
     The Gambia
     Tel:   +220 4376607 / 4376608
     Fax:  +220  4375990
     Mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
     Web: www.nawec.gm

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