Hybrid Systems Power Generation



For years, the power supply to isolated areas where it is unfeasible to build a grid connection, has been done with systems that use fossil fuel generators (diesel, gasoline, LPG ...). Wind and solar energy sources are ubiquitous, freely available and their use can be done in a way that respects the environment. The falling cost of photovoltaic systems and wind, along with the rising price of petroleum products has made these technologies to be already competitive not only in developing countries with limited grid, but also in many applications in developed countries. Although the availability of sufficient wind is not ensured everywhere and its action is more unpredictable than solar energy, the combined use of these renewable energy sources has clear advantages in cost, flexibility and availability, limiting dependence on energy produced by fossil fuels.

A hybrid power system consists of two or more power sources for powering loads or consumers. Since the late 70's of XX century the combination of diesel generators with wind systems has been used to power remote locations. Later on diesel-photovoltaic systems and wind-photovoltaic-diesel have appeared as common solutions. The combination of renewable energy systems without using fossil fuel generation, has become popular in remote applications where noise, space and maintenance of generators is not feasible, and in recent years, substantial price petroleum products has increased the attractiveness of solutions based only on renewable energy. However, the use of these hybrid systems presents specific challenges when the application is professional type, where the system requirements (availability, operability, etc.) are different from those that can claim a domestic application.

Application of hybrid systems

The most common applications for professional-type hybrid systems are those related to telecommunications systems, monitoring and telemetry systems, or signalling.
These systems are located in areas far from urban centers, where it is costly to build the conventional power grid. In many cases access is difficult, so it is very expensive requiring regular maintenance of generators. These are applications that have consumption between 1 and 100 kWh per day and which by their nature require good availability. In lower power systems with the most common solutions would be purely solar or wind, and for systems with higher consumption would be usual complement generators that use a fossil fuel.
In telecommunications systems are used in repeaters and mobile base stations, satellite ground stations, TV gap-fillers, etc.



Hybrid relay stations (solar, wind)


Base Station (BTS) mobile phone (solar-wind-diesel)


DVB-T Gap-filler (solar-wind)


The hybrid power solutions for radio systems are especially favorable for several reasons. Radio systems are often located at high locations to maximize coverage and visibility with connection points, which makes them points for good wind conditions, but away from main roads. On the other hand, these tend to be locations where it is available a tower or mast for installation of antennas, which in many cases to use this structure to secure the wind turbine, reducing costs by sharing a very important element.

In the study Green Power for Mobile by the GSMA (association of all GSM / UMTS worldwide) in 2008, it was estimated there were about 1500 base stations powered by renewable energy, and about 10000 more planned. It estimate that up to 2012 each year about 75000 new stations installed without connection to the electricity grid in developing countries and of these, 50% will be powered by renewable energy, mainly solar and wind energy.


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Considering a BTS with an average consumption of 800 W, the investment could be paid in three years with a single solution or just wind PV and 2.5 years if the system were hybrid (see chart).

Hybrid systems are used in very important applications for monitoring and cathodic protection in locations where solar and wind energy production can be complementary.


Monitoring applications