Solar power in cellular base stations

16 March 2011 |


In recent years, the telecoms sector has shown an increased interest in the adoption of solar technology to generate power for cellular base stations.

Typically, solar power is being utilised in more remote cellular base stations, particularly in developing countries where base stations are often off-grid and reliant on their own power sources. According to a forecast from In-Stat, over 230,000 cellular base stations in developing countries will be solar-powered or wind-powered by 2014.

Why is solar power a more attractive proposition in developing countries?

Many developing countries have leapfrogged fixed-line networks and mainly focussed on developing mobile networks. In parallel to this, many developing countries have also avoided developing a national power grid, and instead focussed on a distributed generation electricity infrastructure. As a result, large numbers of cellular base stations across developing countries rely entirely on local power generation. This typically takes the form of a diesel-powered generator; although often cheap, this does create pollution. In more remote locations, there is the added worry of a tenuous supply chain to bring fuel to the generator – also diesel is a volatile commodity that may rise and drop in price.

Solar technology can therefore be incorporated into the power supply. Photovoltaic cells (PV) are devices that can convert the energy of sunlight directly into electricity. Their reliance on sunlight means the technology is only able to generate power during the daytime, and is therefore a less than perfect solution for a cellular base station to rely on alone. However, when used in tandem with a back-up power source, solar technology can be relied on for peak day power generation, and following installation, the power supply – sunlight – is free.

How have advancements made the technology a more economically viable solution?

The price of solar technology has plummeted in the last couple of years; meanwhile the variety of solar solutions available on the market – which are becoming popular for residential, commercial and utility purposes – has also given the telecoms sector a far greater range of options to drawn upon for cellular base stations.

The overall cost of adopting solar technology depends on where the technology is being installed and the size of the cellular base station. Utility-based solar applications tend to be cheaper than residential or commercial-based ones, and as a rough guideline, telecoms operators could be looking at around $4-6 per watt.

Solutions for cellular base stations tend to be offered by integrators or valuated resellers, rather than coming directly from the large solar panel manufacturers. These specialists are able to identify the best technology solution for a particular location, and sometimes also establish which form of back-up power generation will help to provide the greatest level of value and reliability.

For instance, telecoms energy systems suppliers such as Eltek Valere have branched out into the world of renewable energy and today provide convertors that enable solar panels to run 48v DC loads and charge batteries in cellular base stations.

Which countries have environments best suited to the adoption of solar power?

Off-grid cellular base stations are primarily found in Africa, south Asia, South America, Latin America and the Caribbean – and, with their hot climates, these regions have the best potential for implementing and benefitting from solar technology.

The unique circumstances in India, however, mean cellular base stations there could particularly benefit from the adoption of solar power. As power cuts are so frequent across the country, back-up power sources such as lead acid batteries or fuel cells take on a more important role in the overall power infrastructure. Adding solar power to that existing mix therefore makes an enormous amount of sense and could help cut the reliance on diesel-powered generators.

Remote islands are another good example of where the cost of electricity can be very expensive and solar power has the potential to help combat this.

What other technologies can be used in tandem with solar to generate power?

As previously mentioned, the job of powering cellular base stations won’t be able to rest entirely on the shoulders of solar technology. Because of this, attention must be paid to other energy types that can best supplement the daily feed of solar power.

New battery technologies are developing as a favourable back-up power source to solar power. Regenerative fuel cells or advanced batteries are now available on the market which in some cases even surpass the performance of lead acid batteries. Although lead acid batteries are still undoubtedly cheaper, they too come with their own disadvantages in terms of maintenance and costs.

Again there are specialists on the market which are focussing solely on back-up power and the development of new battery technologies, with Deeya Energy being a good example. The US-based company was formed in 2004 and provides a variety of energy storage platforms for applications in the telecoms and defense industries. Its L-Cell technology was based on technology originally developed by NASA in the early 1970s as a potential energy storage method for long-term space flights, but today claims to offer a large storage capacity and fast-charging capability, which can complement solar and other renewable energy platforms.

Telcos can leverage companies such as Deeya Energy together with other solar power specialists to find a winning combination for their particular cellular base station scenario.