Losses in the Electric Grid on Pemba, Tanzania

Detta är en Kandidat-uppsats från KTH/Energiteknik; KTH/Energiteknik

Författare: Lovisa Gelotte; Olle Wahlquist; [2015]

Nyckelord: ;


Reliable energy is fundamental for a region’s capacity for sustainable development. The island Pemba, which together with Unguja forms Zanzibar, is a semi-autonomous part of Tanzania. The electric power supply on the island is unreliable and blackouts are frequently occurring. Also, there are significant losses in the grid that in 2014 were measured to be as high as 28.9 %. Because of this the local electricity company, Zanzibar Electricity Corporation, ZECO, has started a project, the Change Project, to identify where and why the losses occur and how this situation could be improved.

All the electricity in the public grid on Pemba is supplied through a submarine cable from mainland Tanzania. On the island the public grid only reaches 30 % of the population. The vast majority of the remaining population copes without electricity. This holds back the island’s development and that is why it is important to support ZECO to a sustainable business so they can maintain and extend the grid on Pemba.

This thesis is a part of the Change Project and has its main focus on non-technical losses. The main goal of the study presented in this report was to investigate the reliability of the two types of domestic electricity meters, post-paid and pre-paid, used on Pemba. To do this, 16 interviews were carried out in a selected village named Tumbe. Based on the interviews a load model was created in the software STELLA. The output from the STELLA model was compared to readings of the electricity meters in the 16 interviewed households. This together gave clear indications of the reliability of the meters. The study has also aimed to draw conclusions about where and why the largest losses occur. To investigate this, readings of all found meters in Tumbe were reviewed. Also, data regarding the grid and the electric energy use on Pemba were collected and discussions with ZECO employees were held.

The results from this study are that

-          It is reasonable to believe that the some of the domestic post-paid meters are measuring an inaccurate, too low, consumption. For the interviewed households it is believed that the measuring is in average between 30-45 % lower than the actual consumption.

-          If the losses remain at this level, the capacity in the submarine cable will be reached in approximately 2024. However, if the losses can be reduced the sufficiency of the cable can be extended by several years.

-          A strong correlation between the electricity price level and the presence of non-technical losses was found.

It has been found, based on the results above, that the most important measures to reduce the losses are to

-          Replace all the domestic post-paid meters with accurate ones as soon as possible.

-          Perform regular control of pre-paid meters in order to detect tampering and broken meters.

-          Monitor the electric energy flow in the grid for easier detection of losses, especially electricity theft.

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