GRID EXPANSION

Planning the electrical system in the long term requires knowledge of how potential demand is distributed along the territory. This distribution will depend not only on the location of settlements and economic activities in the territory and their evolution, but also on investment decisions regarding grid expansion and electricity distribution. The existence of power grid constitutes, in itself, a source of development and a reason for the mobility of people with major influence on the geo-spatial evolution of demand.
The electrification strategy that supports the vision Angola Energy 2025 was based on criteria of economic rationality and territorial balance in order to ensure optimal allocation of financial resources and, at the same time, the balanced development of the country together with the reduction of regional asymmetries.
Given the high level of financial effort associated with the electrification of the country, prioritization criteria are required in order to distribute in time the investments. The prioritization criteria, which establishes which localities to electrify first in each Province, shall be defined in accordance with the strategic guidelines for the development of municipalities and in agreement with the Provincial Governments.

Therefore, the power network was geospatially planned based on the perspective of consumers nationwide, according to the following steps:

i) Evaluation of potential demand: All inhabited locations and known industrial projects, across the country, have been identified, georeferenced and characterized according to the potential electricity consumption - current and future - of its population and activities.

ii) Electrification Planning: Based on the existing and planned network until 2017, all sites that should be connected to the National Grid following its expansion were identified (according to supply quality criteria, investment rational and low operating costs). Localities that did not meet this criteria were considered for off-grid electrification through decentralized generation.

iii) Electrification models: Considering the country’s electrification target of 60%, three alternative models prioritizing investment and electrification of the territory until the year 2025 were studied and pondered.

DISTRIBUTION OF POPULATION AGGREGATES OF ANGOLA

i) EVALUATION OF POTENTIAL DEMAND

Based on the preliminary results of the population census conducted in 2014, the characterization of potential demand led to the geo-referencing and estimation of number of houses in more than 22,000 points of consumption throughout the country (see map below).
The results obtained demonstrate the importance of the provincial capitals in terms of population as well as the high population density in the central plateau region, particularly in the provinces of Benguela, Kwanza Sul, Huambo, Huila and Bie (western region), where about 40% of the total population of the country is concentrated.
In the Northern provinces, despite the lower population density, a large dispersion of smaller population centers can be found throughout the territory. The Eastern and Namibe provinces have the lowest population density levels in the country with the population mostly concentrated in the provincial capitals and along the main communication routes.
Finally, the province of Cunene, despite the fact that it holds nearly one million inhabitants, presents quite a differing land use model with respect to the rest of the country, with the population near the Namibian border and Ondjiva spread over thousands of square kilometers under the form of innumerous multi-family units.
The “potential demand” quantification at each site was estimated by sorting the whole of the 22.000 consumption points into 6 different categories of economic development and population density, taking into account both the location of each zone in the territorial development strategy axis, as defined in the Strategy Angola 2025, and the administrative categories, as shown in the table below.

CLASSIFICATION MAP OF POPULATION SITES OF ANGOLA

CLASSIFICATION BY AREA OF THE 22,000 IDENTIFIED SITES

Household consumption per capita and the weight of the tertiary sector were estimated for each zone and calibrated considering the average levels observed and extrapolated in the previous chapter. Also, different growth rates of population by region were taken into account in order to consider migration from rural areas to more developed zones.
Furthermore, in order to evaluate the potential demand for each location, the consumption of the Industry sector was taken int account. This consumption was considered through the geo-referencing and characterization of the demand of identified projects of structural significance and
development clusters.

ii) ELECTRIFICATION PLANNING

The planning of the electricity network should take into perspective a vision of the total electrification of Angola. The network is expected to grow gradually and be dimensioned in order to answer long-term demand needs, while avoiding investments that will quickly become obsolete or which may
become unnecessary.
Based on this premise, the network extension algorithm was developed to progressively inter-connect around 22,000 consumption sites, by order of the shortest distance per consumption unit, until they reach the existing or planned sub-stations. Whenever it was found (with respect to a location or set of locations) that the electricity supply quality could not be guaranteed, or that the investment value and the net operating costs were too high, an alternative electrification solution was considered based on decentralized generation.
Thus, about 13,000 locations with an average consumption of about 10 kW per site are located at too far a distance to justify the extension of the grid. Some of these locations, even though they grouped with other locations creating small local networks (about 1,800), did not meet the minimum requirements to justify an interconnection to the main network.
Overall, only 7% of the population of Angola will be supplied by decentralized generation, representing only 2% of potential domestic demand. On the other hand, about 9,000 consumption sites representing 93% of the Angolan population and 98% of demand may be electrified by grid extension.
The map in figure 13 shows the results of the grid extension algorithm, including all the places which will be economically advantageous to link to the main network in the long term as well as isolated mini-grids that do not meet the minimum requirements for interconnection. The different colors
represent the connection order and priority.

Figure 13 – Results of the grid expansion algorithm

Based on these results, the aggregate sum of the sites and their respective consumptions is determined, which will in turn serve as basis for locating and sizing transformer substations that will connect to the interconnected system.
The map in figure 15 shows the model of total electrification of the territory, linking the existing network to the new sub-stations based on the optimization of distance, charge and voltage levels.
The electrification of Angola through network extension may include up to to 93% of the population, 100% of municipalities and 70% of communes (about 391). The majority of the provinces with the exception of Cunene, Uíge and Malange, would obtain a grid connection rate of around 90%, as shown
on the graphic in figure 14 and 7% of the Angolan population, which represents 2% of demand, could be electrified via decentralized systems, such as small hydros, photovoltaic systems or conventional diesel generation.

ELECTRIFICATION PERCENTAGE THROUGH GRID EXTENSION BY PRIVINCE

MAP OF NETWORK AND SUBSTATIONS IN THE TOTAL ELECTRIFICATION SCENARIO

iii) ELECTRIFICATION MODELS

The full electrification of the territory constitutes a technical and financial challenge not compatible with the 2025 horizon. Therefore, the present Vision assumes the goal and commitment to bring the power supply and modern energy services to 60% of the population by 2025, which implies increasing the existing customer base threefold.
Due to the high concentration of population in provincial capitals and urban areas it is possible to reach the goal of 60% using different strategies. Three different alternatives were evaluated:

“Low investment” Model:

Model based on the expansion of the network with minimum investment, opting to maximize the penetration of each electrified area before investing in
new sub-stations and transmission lines. This model focuses on the almost full electrification of all provincial capitals bringing the network grid to 74 municipality townships only. The remaining municipalities would be electrified by small isolated systems, with higher operating costs but
less investment, fewer customers and lower service level.
This model does not seem appropriate since it encourages an asymmetry of the territory, an exodus from countryside to urban areas and does not create development opportunities in rural areas (figure below).

“Expansionary” Model:

Model based on network expansion to all municipality townships by 2025, completing the network’s 60kV backbone within this timeframe. In this model, the priority would be in the extension of the network and not in its densification. It is expected that only half the population - corresponding to the central areas - in each of the locations outside the provincial capitals would be serviced by 2025.
This model avoids the isolated systems, even if there are hydropower alternatives that would be more advantageous from the economical point of view. In this model the network would reach 100% of the municipalities by 2025 (figure below).

“Balanced or Economy-based” Model:

Model close to the Expansionary one, but which prefers isolated systems that maintain the level of service when competitive small hydropower alternatives exist or when distances per consumption unit are too high. This model also takes into account grid extensions and rural electrification
already underway. The interconnected network covers 130 municipalities (figure below).
Due to the high concentration of the Angolan population in the capital, other provincial capitals and municipal townships, in all the models presented it will be possible to reach the 60% goal through a concentration of the electrification effort in urban areas, including more or less municipalities depending on the model chosen.

ALTERNATIVE ELECTRIFICATION MODELS TO ACHIEVE 60% ELECTRIFICATION BY 2025

The Balanced or Economy-based model is the one that best meets the aspirations of the Angola 2025 Strategy, by promoting a more balanced model of territorial development and optimizing the overall electrification costs, including operating costs. The low investment solution would require a high level of power generation based in generators with high operating costs and would offer a limited level of service in many municipalities.
According to this model, by 2025 the interconnected grid will reach 60% of the population. About 1% will be electrified through isolated or small solar systems. Furthermore, only 31 municipalities are supplied by isolated systems. With the exception of the province of Cunene, in all other provinces
the network will reach at least 30% of its population (see graphic presented below) with Luanda reaching up to 90%.

LOAD DISTRIBUTION PER SYSTEM
According to the criteria adopted for electrification in the “Balanced or Economy-based” model one obtains a distribution of loads between the systems which allows for a greater regional and territorial balance of the country.
The Northern System will grow from 1 GW to 4.3 GW, but will see its weight reduced from 80% to 60%, followed by the Central System with 19%, the  Southern System with 11%, the Eastern System with 7% and finally Cabinda with 3%.

ELECTRIFICATION RATE BY PROVINCE IN 2025 IN THE "BALANCE OR eCONOMY-BASED" MODEL

LOAD DISTRIBUTION BY SYSTEM UNTIL 2025