Bypassing traditional power sources such as diesel fuel and electricity, and replacing them with new eco (News - Alert)-sustainable solutions such as solar panels and wind turbines, not only benefits the environment but also has a positive impact on service providers’ operating expenses.

When building an autonomous cell site, the following components require energy:

•          Base Transceiver Station (BTS)

•          Backhaul equipment (Microwave or satellite)

•          AWL (Aviation warning light: red light on top of pylon)

•          Air conditioning (if BTS is an indoor configuration with a shelter)

Of utmost importance, the base station must be power efficient to ensure that the eco-sustainable power selected is reliable and predictable. Then the correct type of eco-sustainable power must be selected. Each telecom mobile cell site has its own power needs and constraints, which will determine the correct choice of eco-sustainable power as well as its configuration. Alcatel-Lucent (News - Alert) is currently deploying and investigating a wide range of eco-sustainable power options for both energy generation and energy storage. Our comprehensive field trials and extensive partnerships for alternative energy options for telecom power give us a credible authority in this field.

Alcatel-Lucent has been developing and deploying new types of power solutions for over 10 years. This long history, coupled with the industry’s most power efficient GSM base station, results in one of the industry’s largest number of successful field deployments to date powered by eco-sustainable power.

In January 2008 Alcatel-Lucent finished commissioning its 200th solar–powered cell site. The cell site is part of the network of a leading mobile service provider in Senegal. The site — including base station, microwave and all other electrical components — is completely autonomously powered by the sun, providing telecom services to previously unconnected remote communities in the island of Bettenty and surrounding Saloum islands.

The commissioning of the 200th solar powered cell site is an industry landmark for the use of ecosustainable power solutions. It underscores Alcatel-Lucent’s commitment to promote greater environmental responsibility and encourage the development and implementation of technologies that benefit the environment.

Solar panels: The surface area taken by the solar panels on land depends on the energy requirements of the base station and the sun availability in the region. Therefore, a solar power solution is only a cost-effective means of generating power if the base station is power efficient.

Batteries: The batteries are used to store energy produced during periods of sunlight for use when there is insufficient sunlight. Standard backup time is five days.

Regulator: Manages the production and storage of energy.

Frame structure: To hold the solar panels. Different configurations are used to reduce vandalism and site footprint.

•          Independent power supply (48V DC)

•          Reliable and long lasting

•          Cost effective (low operation and maintenance costs, fuel-free)

•          Simple (installation and operation do not require specialized   technicians)

•          Minimum maintenance

•          Silent (noiseless)

•          Environmentally friendly (pollution-free; fuel-free)

•          Geographic limitations (only sunny areas!)

•          Power limitations

•          Can require large installation area (several ten m²)

Wind-generated power has the ability to generate a large amount of power. Depending on the type of cell site, different wind technologies can be used to deploy a wind power solution: either a horizontal axis such as a windmill with two or three blades, or a vertical axis (such as Savonius, Darrieus, or statoeolian).

Alcatel-Lucent is investigating several technologies with partners for power generation of 900 W to 1500 W for horizontal axis and 4000 W for vertical axis.

•          Independent power supply (48V DC)

•          Cost effective (low operation and maintenance costs, fuel-free)

•          Environmentally friendly (pollution-free; fuel-free)

•          Reduced footprint

•          No power limitation

•          Not predictable enough to be the sole source of power

•          Geographic limitation to windy areas

One of the constraints of wind power is that wind power is generally not predictable enough to be a sole source of power to run a base station. Therefore, Alcatel-Lucent is focused on combining wind power with solar panels for a Hybrid Power Solution.

A hybrid power site combines solar panels with wind power to jointly generate power, thereby reducing the required solar panel surface. Together with its partners, Alcatel-Lucent is validating the use of a complete hybrid solar plus wind power solution platform for a BTS.

•          Independent power supply (48V DC)

•          Cost effective (low operation and maintenance costs, fuel-free)

•          Environmentally friendly (pollution-free, fuel-free)

•          Reduced solar panel footprint and number of batteries

•          Secures the spurious wind energy production

•          Reduces the power limitation

•          Geographic limitation to windy and sunny areas

•          Can be a more expensive initial expenditure

Fuel cells produce electricity from Hydrogen. Alcatel-Lucent has field deployments of this solution in the United States and is currently investigating other markets jointly with partners.

•          Noiseless

•          No pollutant emissions

•          Reliable and highly efficient

•          Low maintenance requirements and long life time

•          Compact and light for urban use

•          Able to withstand a wide range of temperatures

•          Costs are high

•          Equipment and maintenance

•          Hydrogen production

•          Procurement and distribution of Hydrogen can be difficult

Biodiesel is natural, eco-sustainable alternatives to fossil fuels such as oil. This form of energy is still in the early stages of maturity for telecom use, and Alcatel-Lucent is working with genset suppliers to study the performance of the various biodiesel options.

Alcatel-Lucent is working with the following types of biodiesel:

•        Vegetable Oil Methyl Esters (VOME): based on colza and sunflower oil. It is a mix of gasoline and VOME that can be used as a short-term solution (since its production requires use of land that could be generating food).

•        Crude Vegetable Oil (CVO): based on the pressed oils of colza, sunflower, palm trees, among others

•        SunDiesel: a synthesized biomass made from straw, wood and paperboard. This solution is not yet mature.

The table below lists some of the attributes of the different biodiesel energy sources. For the mid- to long-term, SunDiesel is the most attractive option due to its manufacturing simplicity and compatibility with the current diesel engine.

Alcatel-Lucent analysis in biodiesel reveals that the least attractive option for telecom use is crude vegetable oil since there are not any quality standards and regulations on its manufacture and storage, so the diesel engine supplier cannot guarantee optimized functionality for a long lifetime.

When designing an autonomous site, energy storage plays an important role in energizing the equipment when the regular energy source is available. Compressed air is used for energy storage, which can be eco-sustainable, depending on the main energy source.

Compressed air is being investigated by the automobile industry as an alternative energy source beyond the hybrid gasoline and electric engine. Alcatel-Lucent is working with partners to validate a prototype in early 2008.

Alcatel-Lucent is investigating two approaches:

•          One energy source: Air

When the main power is available, electricity is used to supply the site and to fill the compressed air bottles. When the main electricity supply is cut off, the compressed air (300 bars) activates the engine to begin to produce electricity to supply the telecom site.

•          Two energy sources: Air + Bio-fuel

When the genset is providing electricity, some of the pistons are dedicated to compressing and filling the air bottles. Once the bottles are filled and the bio-fuel tank is empty, the compressed air bottles are used and the same pistons produce electricity (in reverse mode).

The production of energy from a 400-liter bottle of air, compressed at 300 bars can provide 12 kW for one hour, which is equivalent to enough energy to backup a BTS site of three sectors and six TRXs (1000W) for more than 10 hours.

•          Low carbon dioxide pollution

•          Low temperature

•          Lightweight

•          Simple maintenance

•          Lack of government incentives/support

•          High pressure vessels/system may require safety precautions

The Flywheel is another potential eco-sustainable energy option. It uses kinetic energy stored in a kinetic wheel coupled with a diesel generator. Once the kinetic wheel is launched by the engine, it can regularly take over the generator to power the alternator producing electricity. Therefore the consumption of the diesel generator is drastically reduced. Depending on the wheel diameter, this solution can be used for power production or power storage. Alcatel-Lucent is currently investigating how this solution could be adapted for telecom use.

•          Reduces genset consumption

•          Engine runs 10 percent of the time

•          Works with diesel or bio-fuel

•          Complex technology = high initial cost

Providing innovative eco-sustainable power options to the service provider is one part of Alcatel-Lucent’s power performance offering for telecom wireless networks. Power performance also includes best-in-class power efficiency, innovative outdoor no air-conditioning solutions, and building a network comprised of the least number of cell sites.

Alcatel-Lucent’s long-term presence in high-growth markets prompted the early development of mobile access products with best-in-class power efficiency. Power efficiency is defined as the lowest power consumption for the maximum coverage and traffic load. Reducing the power consumption of the base transceiver station (BTS) for each new generation of products is meaningless if product capabilities are also reduced. As such, the Alcatel-Lucent GSM BTS family of products go beyond simply reducing power consumption to promise power efficiency, ensuring reduced energy consumption with increased coverage and traffic flow capabilities.

Only when a BTS has achieved power efficiency can it efficiently rely upon eco-sustainable power options. Alcatel-Lucent has been deploying and developing new types of power solutions for over 10 years. This long history, coupled with the industry’s most power efficient GSM base station, results in one of the industry’s largest number of successful field deployments to date powered by eco-sustainable power solutions.

In January 2008 Alcatel-Lucent finished commissioning its 200th solar–powered cell site. The cell site is part of the network of a leading mobile service provider in Senegal. The site — including base station, microwave and all other electrical components — is completely autonomously powered by the sun, providing telecom services to previously unconnected remote communities in the island of Bettenty and surrounding Saloum islands.

Power performance from Alcatel-Lucent helps the operator to drastically reduce network operating costs, build sustainable networks that contribute to bridging the digital divide, and have a positive impact on the global environment.
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Edited by Greg Galitzine