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Background

The heart of solar Wi-Fi lies in photovoltaics. Traditional energy is produced through the combustion of fossil fuels, like coal.  Photovoltaics provide energy in a very different way. A single solar panel or a multitude linked together rely simply on the light of the sun; this energy excites electrons in the panel(s), which becomes direct current (DC) electricity.¹

Solar Wi-Fi was the brainchild of Ben Adams, a former United States Air Force engineer and founder of Lumin Innovative Products. Adams conceived the idea while he was still a soldier, hauling a generator through the Nevada desert to power a communications relay.² In 2005, the city of Boulder, Colorado commissioned a project with Lumin Innovative Products to install a solar wifi system in their downtown area. Each system can broadcast a signal in a 25 mile radius.

Following Adams's lead, a new non-profit organization emerged in 2006 called Green Wi-Fi, devoted to producing a cheap, simple solar wifi system that could be easily implemented in developing nations.³ Headed by Bruce Baikie and Marc Pomerleau, Green Wi-Fi quickly caught the attention of the One Laptop Per Child Initiative, whose goal is to construct a $100 laptop to be handed out to children in developing nations. Both groups share similar goals: ensuring free access to information, especially in schools.

Mechanics

Solar Powered WiFi Unit

Source: http://www.green-wifi.org/solutions/technology/. Author: Green WiFi. Permission: Green WiFi.

The mechanisms behind solar Wi-Fi are fairly simple. Each node is composed of: a solar panel, solar charge controller, solar gel battery, ethernet cable, a router, and an antenna. They can be made from easy to find, off-the-shelf items; an individual could build their own solar wifi node themselves for approximately $300. When the light of the sun hits the photovoltaic panel, the electricity produced is directed to either 1) the battery, where it can be stored when the network is not facing heavy demand or 2) the router and antenna, to deliver content to network users (such as email or videos). Solar wifi nodes can be linked together to create a broader range for the wireless signal.⁴

Nodes also typically utilize software to manage signal strength, locating pathways to travel fastest between points, and even to switch themselves on and off at certain times during the day.³ Given the myriad of conditions they must deal with, nodes can be programmed to only run during certain times during the day (for example: during school hours so that children may access the internet), to run on low power (allowing one to surf the web, but not stream videos), or to grant usage priority to certain users (in Green Wi-fi's case, to schools).

The range at which solar Wi-Fi nodes can broadcast their signals varies greatly and is dependent upon the strength of their antenna. Green Wi-Fi has opted to make their units as inexpensive as possible, using a 5dbi omni antenna, which allows their wireless signal a radius of one to two kilometers.⁴ Lumin Innovative Products states that their node can broadcast in a 40.2 km radius (a schematic of their device is not available).²

The most challenging aspect faced by this technology is the necessity of a central broadband access point which the solar wifi node needs to be able to connect with.⁴ In the case of Green Wi-Fi's technology, the node will be able to connect with a central point located within several kilometers. Nodes will connect to one another, and an area with several will have a stronger, wider range of internet accessibility. The more nodes that are added, the greater the serviced area becomes.

Applications

The most talked about application for solar Wi-Fi currently is being able to extend internet access to people who would not have access to it otherwise. It can be utilized to broadcast a wifi signal in developing nations, granting all the benefits of the internet to people who would never see them normally. Green Wi-Fi and OLPC work in tandem to bring cheap computers and internet accessibility to school children who would otherwise have no way to glimpse the world beyond their neighborhood.⁴

Solar Wi-Fi could also prove invaluable in situations like natural disasters, where aide workers need to be able to communicate with their home organizations and their families remotely. Similarly, the military could make use of these nodes when personnel are sent into undeveloped terrain. Lumin Innovative Products specifically mentions engaging in talks with the US military regarding their technology; however, there is no current information to suggest a follow-though. 

Benefits

Solar Wi-Fi's primary benefit is the ability to broadcast an internet signal without needing to be on the grid. Information is available without needing to plug anything into an outlet that siphons power from coal combustion. It is environmentally friendly and sustainable, with a battery to store the “extra” energy that is not expended.⁴

It also has the perk of being a remote system. Depending on the strength of the antenna, a solar Wi-Fi node can be two to forty kilometers away from a central broadband point. Impoverished people who would have never dreamed of reading world news before are able to sit down in front of a computer and pull up a wealth of data with a few keystrokes. Children's education is improved tremendously by the presence of a computer with internet access.⁵ Students who once had only a few books and limited resources are granted real opportunities to research and create projects in a way never imagined before.

Barriers

The greatest challenge facing the implementation of solar Wi-Fi nodes is placing them in an area within range of a broadband access point. Without this initial point to connect to, the node is effectively useless. There are many places in the world beyond the range of the antenna typically used with solar Wi-Fi. They are impossible to reach without either ramping up the equipment used to locate broadband or building a new central point closer.

This, of course, leads to a barrier that comes hand-in-hand with most green technology: cost. Green Wi-Fi has set a price ceiling of $200 per unit for itself, which is reasonable and thus more appealing for very poor regions of the world. However, by limiting the amount they spend, they also limit the range at which they can broadcast a signal from each node. By spending more money, they could reach more people (as with Lumin Innovative Products' 40 km radius).

Finally, solar Wi-Fi is only useful when there are computers present to harness it. While OLPC is working feverishly to distribute technology in the developing world, the reality is that many areas of these nations just simply do not have the ability to utilize solar Wi-Fi. Most individuals do not have home computers, and only certain schools and organizations make use of them presently.

Footnotes

1. "How does solar energy work?." Alternate Energy Sources for a Flourishing Future. 2010. Alternate Energy Sources, Web. 3 Mar 2010.

2. Roston, Eric. "The Future of Energy: Innovation: 7 Cool New Ideas." Time. 23 Oct 2005. Time Magazine, Web. 3 Mar 2010.

3. Terman, Amanda. "Closing the digital divide with solar Wi-Fi." CNet News. 02 Aug 2006. CNet News, Web. 3 Mar 2010.

4. "Green Wifi." Green Wifi. 03 Mar 2010. Green Wifi, Web. 3 Mar 2010.

5. "Educational Technology: The Effectiveness of Computers in Education." University of Michigan: Department of Psychology. 2010. University of Michigan, Web. 3 Mar 2010.