The village of San Felices is located at an altitude of 700 m in Aragón, the Spanish Pyrenees. The lack of infrastructure in the region cause a progressive depopulation of such villages during the 20th century, but rural development projects like the one described below are supporting their revitalization.

The project utilizes a stand-alone PV Power plant comprising a 10 kWp array, 180 kWh battery bank and power conditioner (charge regulator and inverter) to generate AC electricity, which is distributed via a micro-grid. The system was designed for 15 connections but initially provides energy for six houses, a community hall, a church, a hostel/museum and public lighting. Centralizing the PV plant requires fewer modules and batteries than if each house is supplied by an independent PV system. In addition, only one power-conditioning unit is needed to supply all the houses, which simplifies maintenance.

The 90 m2 array of 135 BP 275 (75 Wp) modules is integrated into the roof of a purpose-built building in a way that takes into account the natural and architectural surroundings. The building contains the power conditioning equipment (2 x TapS C-8648 units providing 12 000 Wp MPP tracking regulator and 7,5 kW inverter), 180 kWh Powerbloc battery storage (providing 7 days autonomy) and a back-up propane gas generator for emergencies. It also houses a community hall.

System reliability is enhanced by the Power Conditioning Rack, which controls all aspects of operation. This unit includes the charge regulator as well as converting direct to alternating current of mains quality (230 V - 50 Hz). Operational performance parameters (state of charge, battery voltage, PV current, etc.) are recorded hourly. Key meteorological data are also registered. These data can be seen in real time on the unit's display, or analyzed remotely via modem-link. This facilitates early failure detection and timely maintenance.

The energy service delivered is equivalent to that of the public grid, though attention to load management is more critical. Each house is fitted with an energy-dispenser and meter, which limits the amount of energy available for each user in accordance with their predetermined needs and the contracted tariff. The service scheme is managed by SEBA, Servicios Energeticos Basicos Autonomous, which also provides social and technical support for the end users.

Installation of the micro-grid enabled other infrastructure facilities to be introduced to the village at the same time. Pipes for drinking water and wastewater were installed in the ditches used to bury the electric cables. In a second phase, water purification and wastewater treatment will be completed.

The total cost of the PV plant, distribution, public lighting and water distribution system was just under Euro 221 000 (approximately USD 204 000), co-financed by the European Commission, National, Regional and local governments and the users themselves.

This installation was undertaken as part of SEBA's 'Programma de Energetización Renovable Autónoma (PAERA)', which is now providing energy service to 36 isolated sites in the provinces of Huesca and Zaragoza. SEBA, a non-profit users group found in 1989, has promoted nearly 250 PV installations in rural Spain to date. Together with the Fraunhofer Institute for Solar Energy Systems (ISE), Germany, and the Spanish engineering firm Trama TecnoAmbiental, SEBA has recently produced a brochure about Successful User Schemes for Photovoltaic Stand-Alone Systems, which can be downloaded from ISE website: http://www.ise.fhg.de/english/projects/pv-standalone/index.html.

Information
For further information contact

• Xavier Vallvé
  Trama TecnoAmbiental
  Fax: +34 93 456 6948.

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