Urban Solar

My solar research in Bangladesh can be lumped into two main categories: rural and urban solar. While I am not out tromping through rice paddies, I am trying to understand the market for implementing solar technology in urban Bangladesh, specifically Dhaka. In my last post I discussed the various reasons and lack of infrastructure for why solar home systems make sense for rural areas.  However, it is also possible to make a convincing case for solar in Dhaka. At least, that is what I am attempting to do.

Me on my apartment building's rooftop in Dhaka as 20 solar panels (1kw) are being installed. 

Solar Home Systems

In addition to traveling, playing and exploring in Bangladesh, I am actually here to do some research on solar technology in Bangladesh. My host organization is Grameen Shakti, a non-profit that primarily works on SHSs for rural electrification, but also has biogas and improved cooking stove projects. I have gone on a few field visits now to learn about how solar home systems work, who uses and benefits from SHSs and to familiarize  myself with Grameen Shakti's business practices.

A SHS is made up of essentially three different inputs: the solar panel (generally 10 - 100 Watts), a charge controller and a rechargeable battery. The diagram below shows essentially the basics of how SHSs work. During the day, the sun's light strikes the photovoltaic and a certain portion of this light energy (photons) is absorbed and passed on to electrons. These "excited" electrons then separate from the atom and flow in a single direction creating a current. The current will first travel through the charge controller to the battery, where the electricity is stored. Once the sun goes down, the stored energy from the battery will pass back through the charge controller and electricity will power a combination of lights, small fans, mobile phone charger and in some cases a TV. The purpose of the charge controller is to protect the battery from becoming overcharged (if it is very sunny) or over-discharged (to prevent people from sing too much electricity from the system).

diagram and some more info from: http://www.ashdenawards.org/solar

In Bangladesh, the primary users of SHSs are rural villagers who do not have access to grid electricity. As a result, before purchasing a SHS, villagers will rely on candles and kerosene lanterns as their primary light source at night. In addition to being inadequate sources of light, kerosene emits fumes and both kerosene and candles are fire hazards. As a result, SHSs greatly improve the quality of life for their users, allowing businesses to stay open later, and give opportunities to residential users for reading, studying, working (to earn additional income) and recreation.

Solar home system in Rangamati.