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  • Delta Telecom Power Solutions - News and events
  • 2011.06.28

    Delta delivers hybrid solution for Togocell

    Telecom operators continuously expand their networks from urban to remote areas, where the mains grid is either unreliable or unavailable altogether. Deployment of base stations in such areas has traditionally relied on the use of diesel generator sets (gensets), which is expensive. Rising fuel costs, fuel thefts and the regular maintenance required by gensets in remote areas increase base station OPEX. Local competition has forced telecom operators to look for solutions that will reduce their OPEX.

    Telecom operators are facing the following challenges:

    • Fossil-fuel dependency (global rise in oil prices and limited availability in the future)
    • Transport to remote sites (long distances and expensive transports)
    • Storage of fuel at sites (safety risks: explosion, vandalism, etc.)
    • Telecom sites need to be managed and controlled by on-site personnel (high costs)
    • High maintenance costs (oil, filters, etc.)
    • Limited useful time of diesel engines (needs to be replaced every two years)
    • Pollution (noise, heat and dirt)
    • Optimization of genset operation

    Togocell’s biggest challenge was the viability of remotely located base stations in a telecom network. Is it worth keeping an existing base station running if it generates more costs than revenues? In a standard off-grid site configuration, the genset is running 24 hours a day, 365 days a year. Genset OPEX includes fuel thefts, long and difficult journeys to sites for refuel and maintenance, as well as maintenance supplies (filters, oil, etc.).
    Based on the customer’s requirements, Delta proposed a solution based on the use of solar power, batteries and Delta’s hybrid power system. The objective was to optimize site operation by using renewable energy, and to limit genset operation to a maximum of 12 hours per day. A total of 25 existing sites were upgraded with following equipment provided by Delta:

    • 21 x 230 Wp multi crystalline solar panels D6P230A3A (DelSolar, Taiwan)
    • 1 x hybrid power system including 48 V / 9.6 kW rectifier system, solar chargers (MPPT), DG starter battery charger, AC and DC distribution (Delta, Europe)
    • 1 x 48 V battery string 1,000 Ah (Narrada, China)
    • 1 x 5 m x 7 m PV array support structure (Müpro, Switzerland)
    • 1 x junction box and PV cabling

    Delta’s hybrid system consists of a 4.83 kWp PV array, battery backup for 12 hours at 80 percent depth of discharge for 1.7 kW DC average load, which represents 50 percent of the solar energy fraction and 50 percent of the genset energy fraction. The site includes a solar panel providing enough power to run the site and to recharge batteries. At night, the site is powered by the batteries. If the batteries reach a specified low charge level, the genset starts to power the site and to recharge the batteries. Delta’s hybrid solution provides a stable, modular and secure power supply that is affordable to purchase and maintain. The solution is designed for remotely located, off-grid base stations, and includes remote management capability tailored to the customer requirements. Delta commissioned the site and prepared it for optimization. Delta’s solution helped the customer cut base station OPEX by 60 percent. As a result, the customer decided to order additional equipment for 16 sites (with 9.66 kWp of solar power).

    Delta’s hybrid solution:
    Hybrid system with 4.83 kWp PV array, battery backup for 12 hours at 80 percent depth of discharge for 1.7 kW DC average load.

    Solar energy fraction: 45%
    Genset energy fraction: 55%
    Expected ROI: 5 years

    Delta’s project team:
    Riad Belarbi, Krzysztof Puczko, Simon Jakob and Andrzej Chaberek
    Partner: ADTF

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