SolarNetOne: Solar-powered networking for anyone

Linux and open technologies deliver the Internet anywhere

In many parts of the world, the power grid is shoddy, computers are scarce, and connectivity is even rarer. Thus, as with many other modern practices and technologies, populations are increasingly bifurcated into the "computing haves" and the "computing have-nots." But many are addressing the divide. SolarNetOne is a turnkey Internet hotspot—power, computers, and satellite uplink—you can install virtually anywhere, for less than the cost of a subcompact car.

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Martin Streicher, Software Developer, Pixel, Byte, and Comma

author photo - martin streicherMartin Streicher is a freelance Ruby on Rails developer and the former Editor-in-Chief of Linux Magazine. Martin holds a Master of Science degree in computer science from Purdue University, and has programmed UNIX-like systems since 1986. He collects art and toys.


developerWorks Contributing author
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30 June 2009

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Listen to SolarNetOne founder Scott Johnson talk about his greener planet vision and the critical role open source has played in the SolarNetOne project in this podcast (14:38) on My developerWorks.

If you live in an industrialized nation, chances are you own a computer and enjoy an inexpensive connection to the Internet. Or, if you lack such personal resources, you most likely have ready access to cycles and bandwidth nonetheless, courtesy of your local library, school, or corner coffee shop. In fact, according to Internet World Stats, 75 percent or more of the populations of first-world countries have regular access to a computer and the Internet. For residents of the United States, Australia, Japan, and Western Europe, connectivity is convenient to the point of seeming ubiquitous.

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In stark contrast, less than 25 percent of the world's total population has access to the Internet. In many parts of the world, computers are scarce, and connectivity is even rarer. Indeed, some of these third-world nations have barely any online ingress at all. For example, only one percent of the people of Rwanda can connect to the Internet, and no more than 5 percent of all Africans have access.

Moreover, many countries have makeshift, fragile utility grids, rendering computers and uplinks useless during what are typically interminable outages. Worse, a natural disaster or civil emergency can cause widespread failure of infrastructure—ironically, just as the very same facilities are needed to communicate and coordinate with relief workers and local populations. Shipping containers full of recycled computers from the United States and other world powers do little good without electricity.

Unfortunately—and as with many other modern practices and technologies—the countries of the world are increasingly split into the "computing haves" and the "computing have-nots." Moore's Law has an unfortunate corollary: Innovation widens the digital divide.

Minding the gap

But fortunately many recognize the growing disparity and are taking action to bridge the gap. One Laptop Per Child (OLPC) aims "to create educational opportunities for the world's poorest children by providing each child with a rugged, low-cost, low-power, connected laptop with content and software designed for collaborative, joyful, self-empowered learning." Geekcorps "promotes economic growth in the developing world by sending highly skilled technology volunteers to teach communities how to use innovative and affordable information and communication technologies to solve development problems." The United Nations promotes awareness of the computing inequity each year during World Information Society Day on 17 May.

SolarNetOne is another novel initiative to span the divide. For a relatively small investment, SolarNetOne can deploy a turnkey Internet hotspot—conditioned, renewable power; computers; WiFi; and an uplink—anywhere the sun shines. According to Scott Johnson, founder and lead engineer of the project:

"[SolarNetOne was designed] to go places where there was no existing power infrastructure in place. It's excellent in places where the grid is unreliable or disabled."

Johnson says that he conceived SolarNetOne following a series of conversations with Dr. Vint Cerf, the Internet pioneer and Google's Chief Internet Evangelist. Enamored of Johnson's proposal, Cerf personally funded research and development of the system, and Johnson teamed with Bob Freling of the Solar Electric Light Fund (SELF) and Steve Huter of Network Startup Resource Center (NSRC) to develop a prototype solar-powered network. SELF designs and implements sustainable energy solutions to provide power for water pumping and drip irrigation, health clinics, schools, homes, street lights, microenterprise, and wireless Internet; NSRC assists countries and regions with construction, expansion, and maintenance of Internet infrastructure. See the Resources section for a developerWorks podcast interview with Johnson.

The first SolarNetOne kit was installed at Katsina State University in northern Nigeria in 2007. Since then, the project has refined and commercialized its offering and deployed additional systems in the field.


Uncrate, wire, and go

Each SolarNetOne kit is a self-powered communications network. Energy is produced from a solar array sized to each locale's latitude and predominant weather conditions. The generated power is stored in a substantial battery array, and circuit breakers and electronics protect the gear from overloads and other perturbations.

A basic kit includes five "seats," implemented as thin clients connected through a LAN to a central server. The networking gear also includes a long-range, omnidirectional WiFi access point, and a Session Initiation Protocol (SIP) device. Each kit also includes all the cables and wires required to assemble the system, so few additional materials are required for an installation.

Figure 1 shows the architecture of a SolarNetOne kit. Dashed lines trace power; each solid line represents a network connection.

Figure 1. The construction of the SolarNetOne system
SolarNetOne system

Most of its components are off the shelf and can be replaced easily. For example, the server is an MSI PR210-SEED2 notebook with 2GB of RAM, an 8-GB solid-state hard disk set aside for the operating system, a DVD burner, and a 120-GB external hard disk. An external, extruded heat sink with dual-fan, forced-air cooling significantly lowers the server's operating temperature, ensuring stable operation even in equatorial areas.

The Ethernet hub is a Linksys SR224G. Each terminal is a diskless Sumotech ST166 with 128MB of RAM and a 15-inch VGA LCD. Power for the terminals and monitors is provided from a hybrid 12VDC Power over Ethernet switch through the existing Ethernet wiring, which eliminates the need for extra power drops. The terminals boot via Preboot eXecution Environment (PXE), mount files using Network File System (NFS), and use the X Windows System and the X Display Manager Control Protocol (XDMCP) for remote login to the server.

The diskless thin clients provide many advantages. There is less hardware to fail, and the terminals sip power. Each terminal consumes 4.5 watts while in use, and the LCD consumes an additional 8 watts. (A typical computer consumes 350 watts when in use.) All told, the panels for a five-seat implementation of SolarNetOne must provide only 600 watts of power per hour to enable eight hours of client terminal operation daily and continuous server operation.

The cost for a kit is US$15,000. Maintenance is inexpensive. The solar panels must be kept clean to work optimally. If the batteries are vented, staff must add distilled water to the cells monthly. If cared for properly, a SolarNetOne system should last 20 years or more, although the batteries will likely require replacement after a decade of use.


Powered by open source

SolarNetOne is based entirely on open source technology. The thin clients are powered by the Linux® Terminal Server Project (LTSP). Both the thin clients and the server run the Ubuntu Linux operating system (version 8.04); Apache, Exim, BIND, and OpenSSH provide Web, e-mail, DNS, and remote access, respectively, and Madwifi provides the software for the wireless access point. System software is easily kept up to date with Debian's own Aptitude utility.

Linux was chosen for a number of reasons. First, it is available at no cost—an ideal price tag when an entire SolarNetOne kit costs less than one subcompact car. Linux lowers the initial cost of each system and allows a site to scale without incurring incremental, per-seat software licensing fees. Because a single SolarNetOne server can support up to 50 thin clients, the savings can be substantial, even recouped to add more or improved hardware.

Linux was also chosen because much of the add-on software available for Linux is similarly free (as in beer). All the daemons mentioned above are available and usable without fee, and additional capabilities such as databases, compilers, and scientific libraries are also available at no cost. Thus, once installed, each SolarNetOne kit can be expanded to serve many constituencies and special interests. For example, the SolarNetOne system at Katsina State University provides compute cycles and wireless access to the entire campus. The terminal lab is rarely idle.

In Johnson's experience, Linux is ideal, because a relatively small system can run lots of software. Johnson observes, "Windows® is entirely too heavy to consider for a project like this." Johnson says remote system administration over low-bandwidth links is a breeze with Linux and the command-line shell.

Further, the freedoms provided by the GPL, the Apache License, and other, similar intellectual property grants allow unencumbered access to the source code of applications: Adaptations are not only possible, but variants are encouraged. SolarNetOne customizes Ubuntu Linux for its client and server hardware—specialization that's typically not possible or not financially feasible with a proprietary operating system.

Linux is also immune to most viruses and malware. Such resilience bolsters uptime and availability—one of the fundamental tenets of SolarNetOne.


Success so far

To date, five SolarNetOne systems have been deployed or are in the works, and interest has increased greatly because of early successes and a handful of positive media reports. Johnson is in serious talks with several groups for deployments of 10 or more seats.

The first SolarNetOne installation in Nigeria remains in continuous operation and is used for e-mail, word processing, and Internet surfing. Except for an initial customs hiccup that stranded the system's power hardware in Germany for several months, the system has suffered no major problems. It's widely regarded as the most stable and reliable system in the region.

In point of fact, corruption is often the most significant impediment to deployment. Often, shady customs officials or other government employees can cause problems. Johnson reports that at least one deployment was scuttled by efforts of proprietary interests seeking greater "developing world market share."

Johnson also recently added a salesperson to field inquiries and vet opportunities. The project is now selling the SolarNetOne system for profit and continues its work with non-governmental agencies and non-profits, such as SELF and the Internet Society, which subsidize purchases. Johnson says SolarNetOne remains unique and especially valuable: "I am unaware of anyone else offering a client-server multiuser system with an integrated, long-range WiFi access point and Internet service provider features, such as HTTP, SMTP, DNS, and more. No other project matches the scale of SolarNetOne."

Certainly, there are many opportunities to make an impact. To find prime locales, one must only glance at the gross domestic products of the world's countries and look at the bottom of the list. Johnson notes, "Africa, South America, and the Pacific islands are all excellent targets. We would like to connect the several billion people on the planet who live in areas without stable power or telecommunications to the Internet," says Johnson.


Looking ahead

Questioned by e-mail, Dr. Cerf replied, "SolarNetOne and others like it offer progress towards bringing Internet access to the 77 percent of the world's population that doesn't have it yet."

Johnson says many challenges remain. He wants to continue to reduce power consumption of the system as a whole either to deliver more compute capacity for the same number of watts or to burn less watts for the current capacity. One option, for example, is the use of active-matrix, organic light-emitting diode (AMOLED) displays for the terminals, as AMOLEDs consume less power. Johnson also wants to simplify the components and combine more features into fewer chassis.

Even better, he continues, "We would like to 'push back the envelope' on low-power, sustainable computing and set the standard for power-efficient computing. [The world] must adopt clean power within the next two generations, and this project can lead the transformation to green computing. Most computers waste vast amounts of power, and most wasteful of all is the PC-based network architecture."

Johnson is ambitious, and the project's goals are as lofty as the heavens. "Oh, yes, when I become older and greyer, I would love to see SolarNetOne or its descendants used on other bodies in our solar system."

Now that would make Internet access universal.

If you would like to volunteer your time and expertise to SolarNetOne, or if you would like to donate to the project, contact the SolarNetOne team through its home page listed in the Resources below.

Resources

Learn

Discuss

  • Join the It's all about Green! group on My developerWorks to connect with other developers about energy-efficient computing.

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