Zanzibar’s energy sector is undergoing a significant transformation as the government works tirelessly to secure a sustainable, reliable, and affordable power supply for its growing population and expanding economy. With increasing investment across various sectors, from tourism to infrastructure, the demand for electricity has surged. To meet these demands, the Zanzibar Electricity Corporation (ZECO) has been at the forefront of strategic measures aimed at improving connectivity, expanding the power distribution network, and enhancing the overall capacity of the island’s energy infrastructure with quality electricity.
With a sharp focus on integrating renewable energy solutions and modernizing power distribution network transmission systems, Zanzibar is positioning itself for a more energy-resilient future.
As Zanzibar moves toward a more energy-secure future, the government has prioritized several ambitious projects to increase electricity generation and distribution capacity, including the development of solar PV generator, battery energy storage systems (BESS), and enhanced transmission networks.
These efforts are complemented by measures to reduce power losses and improve grid reliability, particularly in areas heavily invested in economic development. As the country gears up for a future powered by cleaner, more sustainable energy, the roadmap for achieving energy security looks brighter with stronger promises for economic growth, job creation, and improved living standards for all, where electricity stands as a major catalyst to achieve the government vision for Zanzibar.
Current State of Electricity Supply
There are 3 factors we would like to discuss as impeding in proper supply of electricity in our country despite several efforts being taken.
Last Mile Connection Integration/Power Connectivity
Data from Zanzibar Electricity Corporation (ZECO), shows there has been a notable increase in electricity connections among various customer categories. As of December 2024, ZECO recorded an average of 25,809 new customer applications for electricity connections. This marks a substantial growth compared to the average of 15,426 connections in 2020, when the current government ascended to power.
Recognizing the role of electricity in improving the lives of citizens and bolstering the investment sector to strengthen the national economy, the 8th Phase Government, has implemented strategic measures and introduced special discounts to ensure electricity services are easily accessible, affordable, and reliable.
Previously, customers were required to cover electricity connection costs based on the materials to be used, such as cables, poles, meters, and the distance involved. But the Government, through a political pledge by President Hussein Mwinyi directed that, a single-phase meter, which was priced at 464,000 TZS, should be offered at 200,000 TZS. Similarly, a three-phase meter, previously sold at 886,000 TZS, is made available for 402,500 TZS, where for locals and domestic users there should be no charge for the poles neither for cables involved to connectivity.
Power/Electricity Distribution
The electricity service distribution in residential areas across the islands of Unguja and Pemba has reached an impressive 90% coverage. The power distribution network now spans a total of 1,745 kilometers, consisting of 33 kV and 11 kV transmission lines, though the Zanzibar Electricity Corporation (ZECO) aimed to upgrade all remaining 11kV lines to 33kV before the end of this year.
In Unguja, the islands of Tumbatu and Uzi Ng’ambwa have been successfully connected to the national electricity grid. On Pemba Island, the connected islands include Kojani, Kisiwa Panza, Makoongwe, Fundo, Shamiani, Muambe, Kokota, Njau and Uvinje. Zanzibar Electricity Corporation (ZECO) put on record, that some area with the islets receive service 24/7 and 365 days a year with no power interruptions at all, and that is Kokota and Njau both in Pemba.
Through the Capacity Building on Maintenance Project funded by the Norwegian Embassy, the islands of Kokota and Njau, located on Pemba Island, were provided with solar power services at the end of 2022. On Kokota Island, the solar power system has a capacity of 80 kilowatts, while on Njau Island, the system has a capacity of 50 kilowatts.
These two islands were the only ones remaining in the program to provide reliable electricity services to inhabited islands.
Zanzibar Electricity Corporation (ZECO) receives its electricity from the Tanzania Electricity Supply Corporation (TANESCO) through two submarine cables for Unguja island. The first cable had a capacity of 45 megawatts and transmitted electricity at a voltage of 132 kilovolts.
Zanzibar Electricity Corporation (ZECO) receives its electricity from the Tanzania Electricity Supply Corporation (TANESCO) through two submarine cables for Unguja island.
Due to prolonged usage, this cable now has a capacity to carry only 30 megawatts. The second cable has a capacity of 100 megawatts and also transmits electricity at a voltage of 132 kilovolts.
While for Pemba Island Zanzibar Electricity Corporation (ZECO) receives its electricity from the Tanzania Electricity Supply Corporation (TANESCO) through a single submarine cable with a capacity of 20 megawatts and transmitted electricity at a voltage of 33 kilovolts, and cover 72 km of the sea bed from Tanga Tanzania Mainland to Pemba.
Currently, both cables for Unguja Island have reached their maximum electricity carrying capacity. For the first cable, with a capacity of 30 megawatts, is now transmitting 28.8 megawatts of electricity. The second cable, which carries 100 megawatts, has already utilized 93.3% of its capacity, leaving only a 7% buffer. The Pemba cable still have good buffer as electricity carrying capacity is 76%.
Challenges in Power/Electricity Distribution
Electricity distribution in the Zanzibar archipelago is faced with the challenge of infrastructure that is overwhelmed by the growing demand and consumption. This increase is driven by the rapid pace of investment across various sectors.
In the last four years Zanzibar has witnessed un-proportional increase between investments and electricity infrastructure. Capital investment to various mega projects does not go hand in hand with capital investment in power distribution network to meet power demand, as a result ZECO now working tirelessly on various business re-engineering concepts to balance between surges on economic investments and its power lines infrastructure.
The existing infrastructure network does not align with the ongoing increase in investment, leading to significant congestion and load stress to its power line, where most are over capacity, thereby resulting in unreliable electricity service while ZECO fail to meets its customer charter.
This has led to some areas, particularly those with high investments in the tourism sector, such as Kizimkazi, Makunduchi, Jambiani, Bwejuu, Michamvi, Chwaka, Uroa, Kiwengwa, Matemwe, and Nungwi, facing challenges of power outages or low voltage electricity during peak times, especially in the evenings and early mornings, though now ZECO has in place robust action plan to address the situation at short time possible.
Apart from Town Centre, Zanzibar has six feeder HT lines, two to the north 16 megawatts to Matemwe and 17 megawatts to Nungwi. Also has two HT lines to the south, 17 megawatts to Chwaka and 17 megawatts to Kizimkazi, there is another two HT lines to Fumba each of 17 megawatts but facing some challenges to take load up to 17 megawatts since the HT line conductor in most part is 50mm core.
As temporary measures ZECO is currently building a new HT line from Mtoni substation to Mpendae substation of 6km to take off 12 megawatts load from new Fumba line to create a buffer to easy load from HT lines to Kizimkazi as explained below, the new HT line will connect Migombani. Mazizini, Mbweni, Chukwani, Jang’ombe, Mpendae, Magomeni, Kidongo Chekundu, Kwahani and Mikunguni off from new Fumba line.
Since the new Fumba HT line is extended to Kisakasaka, simultaneously ZECO is building a new HT line from Kisakasaka to Fuoni Kibondeni of a 2 km length aimed to connect Chwaka HT line with new Fumba HT line, then ZECO will take 6.8 megawatts load off Chwaka HT line to new Fumba line, that will create a buffer of 6.8 megawatts plus 1 megawatt original Chwaka HT line has to form a buffer of 7.8 megawatts.
ZECO is also building a new HT Chwaka to Charawe of a 4km to connect Chwaka HT line to Michamvi through Charawe, then ZECO will connect Michamvi, Ukongoroni, and Bwejuu to Chakwa HT line and off that area from south HT lines, that will take load of 3.8 megawatts from south HT line to Kizimkazi, to make the Kizimkazi HT line with 17 megawatts capacity but runs an overload at 19 megawatts to reduce its load from 19 megawatts to 15.2 megawatts.
At that point ZECO HT lines to Kizimkazi will run within the carrying capacity and current frequently automatic power shut down on ZECO HT lines to Kizimkazi will disappear from the national grid. ZECO aims to complete this task by the end of January 2025.
Why Power Outages?
Power outages occur because, within ZECO’s network, feeder lines breakers are in place to manage stress on the lines automatically. These mechanisms help mitigate potential damage, including fires, by preventing the lines from exceeding their electrical carrying capacity. Once the stress on the lines subsides and normal conditions are restored, the electricity flow is resumed, and power service continues without interruption.
Some of the feeder lines exceeds its capacity by 2 megawatts to cause frequently automatic shutdown, which cause havoc and displease the investors. This outcry is seriously taken by the government, and (ZECO) has been tasked to work at minimum timeframe to come up with temporary solutions, short plans and long-time plan to remedy the situation. Building of the new HT lines is one of the temporary steps on the solution to the problem.
Power/Electricity Loss
Zanzibar faces challenges of electricity loss through both technical and commercial losses. Prior to 2020, technical losses reached levels of 5% to 7%, while commercial losses amounted to 40%.
To address these losses, ZECO has established a Revenue Protection Unit. The goal of this unit is to ensure that all individuals involved in electricity theft are identified and legally prosecuted. Currently, the level of electricity loss has decreased to 16.3%.
Government’s Plans and Solutions
ZECO and the Government has never ceased to look for plans and solution to the challenges of providing stable power to the clients for conducting their business as well as enjoying stable power in their homes. We can highlight such plans and solutions.
Upgrading the Transmission Network
Efforts are underway to expand the transmission infrastructure to reduce power losses, improve efficiency, and ensure reliable delivery of electricity across Unguja and Pemba. The government is committed to improving access to electricity services by investing in new electricity distribution infrastructure, including upgrading the remaining 11kV lines to 33kV, revamping its substations at Mtoni, Mpendae, Mwanyanya and Welezo with 60MVA power transformer and 30MW line breaker from current 17MW.
The Government is in discussions with the African Development Bank (AfDB), where Zanzibar will install a new 220 MW cable operating at 132 kilovolts. This cable will run from the Ununio area in the Dar es Salaam region and end at the Mtende area. It will later be laid underground and extended to the Makunduchi area, southern part of Unguja Island, where a new substation is underway.
In the meantime, Zanzibar Government has also put on the table the concept of replacing its undersea cable of 45MW built since 1980 to 100MW and is very ambitious to see new Zanzibar investment portfolio which surges in the last four years, go hand in hand with new Zanzibar power security scheme not to disappoint the pace of new investments to include Zanzibar mega projects.
Strengthening the Distribution System
Many areas experience low voltage because electricity is transmitted from a single substation in Mtoni on Unguja Island, runs at a long distance which operates at a voltage rate of 33 kilovolts without being boosted, while HT lines carrying capacity degraded with more load in between, as a result of new Zanzibar developments.
Investments are being directed toward upgrading distribution networks to enhance their capacity and reliability, minimizing frequent outages experienced in urban and rural areas. In addressing the situation ZECO will make use of all available technology to include Solar PV, and Battery Energy Storage Systems (BESS).
The government, through ZECO, has been taking various measures to address the challenge of power outages. The Ministry of Water, Energy, and Minerals which is implementing an electricity system improvement project through the American company NOVAVIS. NOVAVIS has installed 24 voltage regulators in eight (8) locations on the island of Unguja. These locations are: Ubago, Kitogani in the Southern Unguja and Upenja, Donge, Mahonda, Chuini, and Fukuchani in the Northern Unguja.
This step has reduced the challenge of low voltage in many areas of Southern and Northern Unguja. The next step is the installation of these devices on the island of Pemba. With funding from the World Bank (WB), through a concessional loan aimed at the implementation of the Zanzibar Energy Sector and Transformation Access (ZESTA) Project, ZECO will receive USD 132 million to execute various projects, including the installation of a Supervision Control and Data Acquisition (SCADA) system in the Mtoni area. SCADA plays a critical role in the electricity subsector, enabling the efficient, reliable, and secure operation of power generation, transmission, and distribution systems.
Investment in Renewable Energy Projects
Zanzibar is focusing on increasing its electricity generation capacity by exploring additional sources of energy, including renewable options like solar and wind and encouraging foreign direct investment in renewable energy projects, aligning with its goals for sustainable energy solutions.
Alongside this, the government is constructing a solar power generation facility (Solar PV Panel) which will generate 18.5 megawatts. This project is expected to be completed by 2027. All these efforts are aimed at ensuring Zanzibar power security with natural disaster resilience.
In addressing the situation ZECO will make use of all available technology to include Solar PV, Battery Energy Storage Systems (BESS).
These initiatives are also being implemented in other areas of Zanzibar. Currently, the government is in the final stages of negotiations with an investor to install Solar PV panels with a capacity to generate 30 megawatts in the Matemwe area.
Power Storage Solutions
Zanzibar is exploring advanced energy storage technologies, such as battery systems, to store surplus energy for use during peak demand or outages. ZECO plans to install a 40-megawatt Battery Energy Storage System (BESS) at the Mtoni substation. The BESS will store electricity for use during emergency situations.
To ensure Zanzibar overcomes the electricity challenges during the period when long-term projects are yet to be completed, the government has announced a tender for electricity generation in this transitional phase. The plan involves producing 50 megawatts using gas energy and 30 megawatts from waste-to-energy solutions to meet the growing demands of economic activities. The process is currently at the evaluation stage. All in all, Zanzibar under the leadership of the most delivering President Dr Hussein Ali MWINYI is geared to transform its economic and social landscape to impact the way of life and business in Zanzibar.
