Editing Cell site (section)

== Off-grid systems ==
{{more citations needed section|date=April 2012}}
An off-grid cell site is not connected to the public [[electrical grid]]. Usually the system is [[off-the-grid]] because of difficult access or lack of infrastructure. [[Fuel cell]] or other [[backup power]] systems are added to critical cell sites to provide day-to-day and emergency power. Traditionally, sites have used internal-combustion-engine-driven generator sets,<ref>[http://fr.chfca.ca/itoolkit.asp?pg=BALLARD_07132009 Ballard fuel cells to power telecom backup power units for Motorola] {{webarchive |url=https://web.archive.org/web/20110706172302/http://fr.chfca.ca/itoolkit.asp?pg=BALLARD_07132009 |date=6 July 2011 }}</ref><ref>{{Cite web|url=http://cleantech.com/news/3674/india-telecom-get-fuel-cells|archive-url=https://web.archive.org/web/20101126130543/http://cleantech.com/news/3674/india-telecom-get-fuel-cells|title=India telecoms to get fuel cell power|archive-date=26 November 2010}}</ref> however, being less efficient than public power, they increase [[operating expense]] and are a source of pollution (atmospheric, acoustic, etc.) and some are in areas protected by environment and landscape conservation.

[[Renewable sources]], such as [[solar power]] and [[wind power]] may be available where cell sites are placed. The first off-grid mast in the UK was installed in 2022 in [[Eglwyswrw]], [[Wales]].<ref>{{cite news|publisher=BBC News|date=15 June 2022|url=https://www.bbc.co.uk/news/uk-wales-61798401|title=Pembrokeshire: Wind and solar powered phone mast in UK first|access-date=15 June 2022|archive-date=15 June 2022|archive-url=https://web.archive.org/web/20220615010846/https://www.bbc.co.uk/news/uk-wales-61798401|url-status=live}}</ref> This can reduce the cost of fuel to the cell site or telecom tower by up to 75%. They can be backed up by a fuel generator system which allows the cell site to work when the renewable sources are not enough. One such energy production system consists of:
* [[Solar power]] generator
* [[Wind generator]]
* Electrochemical generator fuel cells

Electrical energy from intermittent sources is stored in [[secondary batteries]] which are usually designed to have an average of two days of self-sufficiency, also known as autonomy, to allow time for maintenance personnel to arrive at site when a repair is needed.

The renewable energy systems supply electrical power when available. The fuel cells are activated only when the natural sources are not enough to supply the energy the system needs. The emergency power supply (the fuel cells) is designed to last an average of ten days. In this way the structure is completely self-sufficient: this enables the maintenance team to pay only few visits to the site, since it is usually hard to get to.