Red Sun’s research on building Asymmetric Network Infrastructure is in full swing. At the most basic level, the greatest challenge to the growth of networked infrastructure (to include mobile devices) is access to sustainable and affordable power generation. For example, looking at per capita power consumption by year (1), it is easy to see that everywhere in both emerging and developed economies, power consumption is growing rapidly.
Despite this, people still lack power in many areas of the world. Centralized power grids can provide power, but are currently not sustainable in many areas and will take years before they are well established. Contrast this with mobile phone population and you’ll see that in many places, access to cellular networks is outstripping access to continuous power. 93% of Africans have cell phone service (2) but access to electricity (3) is much lower, especially in sub-saharan Africa.
A prominent example is the lack of both capital and foreign investment needed for infrastructure projects (4). Areas can be seen as “high-risk” for infrastructure development because of their remote geography, low-population density, low-power consumption, and the high cost associated with logistics and maintenance support. Yet even while access to power remains low, access to mobile devices remains high. How can we bridge the gap between increasing access to electrical power and the internet, without enormous costs for the end user?
The answer is through distributed solar power.
What do we mean by “distributed” solar power? Distributed solar power means starting small, and generating power locally, while also building confidence in solar power as a reliable power generation resource. There are three big factors on why solar is increasingly competitive:
- Solar Power generation is more efficient than ever and produces Direct Current
- Improved battery storage capacity and device electric power consumption efficiency
- Lithium-Ion batteries are the standard for powering connected devices
It is also time to be honest that unless renewable resources begin to be adopted, not only will we further destroy our planet’s ecosystem, but fossil fuels will run out before a smooth transition to renewables can be made.
Solar Efficiency and PV Cells
To understand why solar power is effective as a power source, it helps to understand how solar energy works. Photovoltaic (PV) Cells, also called Solar Cells(5), are the panels that absorb sunlight to generate voltage and electric current. This process is referred to as the “Photovoltaic Effect” (6), defined by the Encyclopaedia Britannica as the “process in which two dissimilar materials in close contact produce an electrical voltage when struck by light (7) or other radiant energy (8).”
This process uses materials such as silicon, to absorb the photons available in electromagnetic waves that reside in sunlight. The photovoltaic reaction then produces Direct Current (DC) electrical power, like the type of power you charge your phone with, based on the amount of power the solar panel is able to absorb from sunlight. The electromagnetic power available in these waves is referred to as “Solar Irradiance.”
Solar irradiance is measured by a device called a pyranometer. The pyranometer detects the wavelength of the light spectrum it is pointed towards, providing a value representing wavelengths between 300 and 2800nm. This value correlates to the solar spectral irradiance represented by power per square unit, or Watts per Meters^2(w/m^2). This sounds confusing, but an easy way to visualize solar irradiance is by comparing two lightbulbs, a 20 watt light bulb versus a 100 watt light bulb. Both will light a room, but the 100 watt light bulb will shine much brighter (9). So why is this important?
By measuring solar irradiance, we are able to predict the total amount of power being absorbed by a square meter of a surface. The more power available from solar irradiance, the more electricity we can generate from it. This is why solar panel efficiency is so important, because the better the efficiency, the more electricity solar panels will generate with a smaller area. By utilizing new techniques (10), sun tracking mirrors (11) and “Supercritical” thermal methods (12) solar power generation is becoming more efficient than ever! The National Renewable Energy Laboratory offers a great listing of current photovoltaic efficiency rates over time (13).
Storing and Using Solar Energy Everyday
While solar panel efficiency is rising, in some places it is becoming even cheaper than fossil fuels (14). India is pacing itself (15) to thrive on renewable energies by 2020, ramping up investments that will drive down access costs. Parts of the United States are experiencing the benefits of investing in solar technology (16) as well, with electricity cost rates rising slower in states with the most renewable energy sources. While solar is getting cheaper, energy storage and consumption is changing as well. Alternating Current (AC) outlets, like the ones in your house, still provide much of our power to items such as lighting and the television. The connected devices we use, such as laptops and mobile phones however, are powered by Lithium Ion (17) batteries.
These batteries are charged with Direct Current (DC). Alternating Current transforms into Direct Current by way of an adapter, and a lot of power is lost through this energy transfer. You probably have used an adapter already.
Because Solar Panels produce DC, our connected mobile devices use DC, and Lithium Ion batteries use DC, it isn’t surprising to see why sustainable energy and network society go hand in hand. In fact, devices such as smartphones and laptops account for only about 25 cents and 8 dollars a year (respectively) in terms of energy consumption in the United States. “To be specific, your iPhone battery holds a charge of 1,440 mAh, or about 5.45 watt hours. If you fully drained and recharged your phone everyday, then over the course of a year you would have to feed it about 2,000 watt hours, or 2kWh.” (18) Considering this, it seems that powering connected devices solely using cheap renewable energy seems extremely feasible, especially in places that do not have access to centralized power grids.
By providing cheap access to small powerbanks and solar panel technologies in rural areas where consumption of power is low but demand for electricity to power mobile devices is exploding, people are able to have access to consistent power without the high cost and maintenance of large centralized power grids.