Crash Course: Solar Energy

The Center for Technology and Development (CTED) is launching its CTED Crash Course, a new feature on its blog, which will share some essential background information that will help explain what we do here at the intersection of innovative technology and economic development. We hope to shed some light on some of the basics of solar energy, mobile technology and Internet accessibility that are at the very core of CTED’s research. We also hope to provide some economic and developmental context in light of these areas of research and to examine their importance in solving some of the issues facing the developing world.

For our first CTED Crash Course, we will look at solar energy – what it is, how it works, why it matters and how it can help those in developing regions. To begin, at its most basic, solar energy is the energy from the sun that is transformed into energy that is then used or stored. When we talk about “energy” from the sun, we are talking about the warmth that we feel from the sun, the heat that makes sand on the beach too hot to walk on, the same energy that plants convert into sugars to grow. The sun’s rays warm matter, causing particles to move and thus generate heat and energy.

People have been capturing this energy for centuries – in ancient times, the sun was used to heat homes, in what is known as passive solar energy, and magnifying glasses were used to concentrate the sun’s rays to start fires. Native Americans, Greeks and the Romans used the orbit of the sun in their urban planning, building south-facing homes that would capture the heat during the day and then slowly release that stored heat at night. The Romans later discovered that trapping the sun’s energy in a glass box would allow them to grow exotic plants, creating the greenhouse.

Today, passive solar energy is widespread and taken into account for everything from urban planning to water heating systems. However, as technology developed, the use of active solar energy soon became the forefront of making the sun one of our greatest energy resources. Active solar energy refers to the use of technology to convert said energy into useable forms of power. There are two main methods to doing so – concentrating the sun’s rays using mirrors or lenses or through photovoltaic reactions.

Concentrated solar power (CSP) arises from the heat created when solar energy is concentrated through the lenses or mirrors which are attached to an engine which is then connected to an electrical power generator or to boil water and create steam energy. It is the same idea as using a magnifying glass to start a campfire – you angle the glass towards the sun until it focuses the rays into a small point. Just as you have to find that exact angle to light the fire, concentrated solar power systems utilize solar tracking devices that follow the arc of the sun throughout the day in order to maximize the efficiency of the system. Today, parabolic troughs are among the most widely used type of CSP systems. In the Mojave Desert, the Solar Energy Generating Systems (SEGS) is the largest solar energy generating facility in the world, reportedly generating enough power to power over 200,000 homes. In Seville, Spain, the world’s first commercial operating solar power tower concentrates the reflection of over 1000 mirrors to a tower that then uses that heat to boil water and operate a steam turbine.

Photovoltaic solar systems convert solar radiation into an electrical current that is then used directly or stored in some manner for later use. In 1839, French physicist Edmund Becquerel discovered that certain minerals’, such as selenium, conductivity increased greatly when exposed to the sun. By the 1880s, the first solar cell – much of what we see or think of today when we talk about solar energy – was developed, though with an efficiency of around 1%. As the technology developed for photovoltaic cells, increasing this efficiency number became the Holy Grail that drove innovation and development.

Another factor that drove development was the evolving dependence on other energy sources, namely fossil fuels, and the sense that eventually those resources would run out. This idea spurred the initial development in the 1860s, but once the Industrial Revolution grabbed hold and King Coal announced his abundance and dominance in industry, further innovation in the realm of solar technology was placed on the backburner. It wasn’t until the 1940s and 50s in America, that real strides in making solar technology both economically and efficiently viable occurred. In 1954, several scientists at Bell Technologies in the United States stumbled upon the use of silicon as part of the conductor – a discovery that pushed that magical efficiency return to 6%. The first public sales of solar cells began not long after, but at a staggering cost of $300 per watt. If you think of your average incandescent light bulb, which are around 40 watts, you can imagine how solar panels remained out of reach for most people.

However, only recently has the technology developed enough to provide significant efficiency and monetary returns to make solar energy one of the most available and feasible renewable energies on a large scale. With the oil crisis of the 1970s, the production of photovoltaic solar cells increased dramatically and brought the average price per watt down to $7/watt by 1985. Since then, many countries have made the push to develop solar industries and reliance upon it as a primary source of energy. Despite the widespread subsidies afforded to natural gas, many countries such as the United States, Japan and Germany chose to begin offering incentives for shifting to solar power. Germany offered feed-in tariffs that subsidized new solar installations, the cost of which is spread across all national electricity providers.

Though, when we look at solar power, an important aspect that need not be overlooked is the manner in which it can be used in rural areas and developing countries, where there is not access to an existing power grid system. For many countries, expanding the electrical grid is too costly to cover areas with low population densities. In fact, an estimated 1.6 billion people do not have access to electricity. The people in these communities must find other ways to generate power – gas generators, fire, and now the sun. Solar home systems (SHS) are photovoltaic cells connected to a battery, which is then used to power or charge devices. With a basic SHS, a family is now able to increase their own productivity – students are able to study at night, a mother who is also a seamstress is able to work at night from her own home – while creating safer living conditions for that family. With the power that an SHS provides, that family is now able to utilize technology in ways not possible before. They are able to charge their cell phones or use household appliances such as televisions or refrigerators. The solar system is a key to a world of possibilities not previously available to them.

However, there are several challenging issues and obstacles that should be noted. One of the biggest challenges of owning a solar home system is the high cost of maintenance. For many, if their system breaks, they must find a technician and then wait for him/her to come from the city or town to come out to their village for repair. Not only is this a lengthy process, but most often a quite expensive one as well. Several CTED graduate students are developing an innovative add-on to a basic SHS that uses SMS technology to monitor the health and status of the solar system in real time, driving down maintenance costs and increasing the system’s sustainability. SIMbalink is a device that routinely, as frequently as every hour, and sends a system update text message to a regional technician. This allows that technician to see exactly when something occurs that threatens the sustainability or lifespan of that particular SHS, such as dust on the PV cells or if the battery is being used improperly and drained too quickly. This creates a constant stream of communication between the owner of the device and the company that sold it and aids in maintaining it, leading to a greater sense of accountability between both the device user and the solar company.

Furthermore, solar systems in small, rural communities also present a valuable economic asset. The owner of the SHS now has a valuable commodity that they have incentive now to maintain. Their solar home system can also provide an economic return for them – which they can use to repay the loan they used to get it or as a means of income. The SIMbalink module also allows for daily monitoring of battery usage, which can be used to charge other community members accurately for their usage. Thus, solar systems in rural areas present opportunities to solidify community links and to foster shared responsibility.


About CTED

CTED, as part of the New York University Abu Dhabi Research Grant, is a multidisciplinary research lab that focuses on combining economic principles, technological advances, and human-centric design to create innovative solutions for the problems experienced in emerging regions.
This entry was posted in Crash Course, Energy. Bookmark the permalink.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s