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Cabo Verde

African island goes green with solar micro-grid

REM Lunes, 26 de marzo de 2012


A new rural solar photovoltaic (PV) micro-grid has been commissioned on the island of Santo Antão (Cabo Verde) financed under the ACP-EU Energy Facility programme and led by local private water company Aguas de Porta Preta, in consortium with the local municipality and other entities. An individual energy allowance scheme has been rolled out to provide 60 homes in a village with power from the array.

African island goes green with solar micro-grid

While you were probably having a normal day at work on Thursday 9 February 2012, a small village in Africa experienced its first 24 hours of electricity.

Monte Trigo is a village in Santo Antão, Cape Verde’s westernmost island. The 60-family community is only reachable by boat and is completely dependent on fishing and its trade with nearby villages. The need of ice, which so many of us take for granted, is a matter of survival for the inhabitants of Monte Trigo. They need it for preserving the fish, hence the constant and frequent five-hour boat trip (each way) to São Vicente, the nearest main island, for ice purchase. It is a process far from efficient, wasting precious time that could be used in other activities.

Let there be light

It was to respond to this need that local entities came together to develop an off-grid solar energy project. It was financed under the ACP-EU Energy Facility programme and lead by local private water company “Aguas de Porta Preta” (APP), in consortium with the local Municipality (“Câmara Municipal de Porto Novo”, CMPN) and other entities.

The facility installed in Monte Trigo is a Multi-user Solar micro-Grid (MSG) based on a photovoltaic generator, a storage battery, an electricity monitoring, control and power conversion equipment and an LV distribution grid. The 27.3 kWp PV generator is mounted on a wooden pergola that provides shade to the village’s schoolyard and therefore added value to the community. Power from the PV power plant is delivered through an 800-metre aerial distribution line to the 60 final end-users, among them a school, a church, a kindergarten, a health centre, a satellite DVB TV system, three general stores and 22 streetlights.

Challenges and added-value of controlling energy demand

Some of the major challenges of a rural electrification project that uses renewable energy generation are related to the users’ understanding of the technology, the electricity service, and operation and maintenance activities.

Generally speaking, concepts such as the sustainable and rational use of solar energy, and the implications of the different charging levels of the batteries, are not easily understood or introduced into the end-users’ daily habits. To address this, the concept of Energy Daily Allowance (EDA) was established in the Monte Trigo project.

The EDA makes the demand control more intelligent and flexible by introducing the concept that the energy available to each user is caped at an agreed maximum. This ensures that the plant operates within its rated design and there will be no blackouts or unforeseen increases in operating costs. Also, higher back-up diesel fuel consumption and components like batteries and inverters operate within their specified range, to increase efficiency and lifetime. This limit is, nevertheless, flexible according to the plant’s condition and on very sunny days users are encouraged to make use of the surplus generation at no extra cost.

In the initial phase of the project, the designers of the facility system interviewed users to access their energy needs and their willingness to pay the 24-hour service. This ensured that the community felt involved, as each family chose to contract the EDA monthly fee that better fit them. It also allowed technicians to understand in detail what would be the best technical solution for the village.

Trama TecnoAmbiental, one of the companies behind this project, has used the EDA concept in other rural electrification projects in different cultures and parts of the world and it has been well accepted because it responds to users’ needs accurately, guides them through the management of energy use, and also establishes a fixed monthly energy budget.

The implementation is done through a special type of meter (called an electricity dispenser) that permanently shows the user the available energy allowance and includes a signal to encourage or refrain consumption, always according to the plant’s condition.

The EDA is a vital design feature, as it is the element from which the PV generator (and then all the other major system components) is sized. So it is essential to determine in a detailed and accurate way each user’s energy demand. It also estimates any future increase, according to the community’s specific social and economic environment.

Furthermore, and from a technological stance, the EDA enables components like batteries and inverters to operate within their specified range and so to increase system efficiency and to lengthen their life duration.

A tailored energy service

The Monte Trigo project’s service was set-up using a mixed private/public-utility concept, in which CMPN and APP are directly responsible for the service management and operation and maintenance (O&M) activities of the facility.

Tariff collection is based on fixed monthly rates related to the EDA and was established within the population’s payment capacity. This not only sustains O&M but also partially pays back the capital costs.

The O&M activities themselves are organised in order to involve local users and are structured around a concept of three levels of involvement: (1) final users, (2) fist-level O&M up-keeper/user and (3) second-level O&M technicians.

The first level includes the users themselves, as they are the first component of a successful and durable service. The objective is not only to support them in maintaining their home installation, but also make their electricity consumption behaviour and habits more efficient.

The second level includes a team of trained users, responsible for the basic daily operation, maintenance and, in case of specific alarm and issues, reporting.

Finally, the operator’s technical personnel are the focal point for problem-solving, ensuring substitution when end-of-life is reached, as well as for specific maintenance and overall activities.

To ensure the successful implementation of this approach, training and capacity-building sessions where performed by Trama TecnoAmbiental previous to and during commissioning activities in all three levels. They included theory and practical demonstrations to levels two and three, and also to the project developers’ (APP, CMPN) personnel.

In the same way, the final users where trained to understand the dispenser/meter operation and to follow the good habits needed to use a PV generation-based electricity service. Practical demonstrations were also performed, directly involving the users, who responded enthusiastically.

Monte Trigans were surprisingly well prepared to accept the basic concepts introduced to them and in a few days started to efficiently manage their energy allowances.

Importance of strong partnerships

As with any successful rural electrification project, Monte Trigo involved many partners from different parts of the world working together. In isolated communities such as this one, the quality of the different components of the system gains new importance, so it is essential to involve the right (and experienced) companies for each job. In this case, the project involved mainly three companies: Trama TecnoAmbiental, ATERSA and Studer Innotec.

From the first days of operation, the local authorities showed their satisfaction with the new 24-hour electricity service, as demonstrated by the visit of the President of the Republic of Cape Verde (Dr. Jorge Carlos Fonseca) and of the European Union Ambassador in Cape Verde (Mr. Josep Coll) shortly after the project was commissioned (see pictures 6 and 7).

But most of all, it is the enthusiasm of the Monte Trigo population which demonstrates the success of the project. The villagers’ habits adapted very easily to their new quality of life and what it brought.

Major changes are already shaping the life of this community: one user already bought his first refrigerator (an A+ energy rating!) and local workers brought in a welding machine from the nearby village to fix a structure with a defect. It was the first time they were able to use something like this in the village.

It is expected that with the two ice machines capable of up to 500 kg/day production using peak of the day, solar surplus generation will improve the commercial activities on which the village sustains its economy.

[Editor’s note: Article kindly provided by Simon Rolland, Secretary General, Alliance for Rural Electrification.]

For additional information:

Alliance for Rural Electrification

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