Hello EWB friends and family. As the implementation trip for the 2018 Peru Solar project with the village of Labramani approaches, I would like to give some background. This first post is all about alternative analysis, an important part of the EWB process. The Alternative Analysis Report is a report EWB required each chapter to turn in before they get approved to take their implementation trip (the one where they install the system and educate the community about it). The purpose of the report is to weigh different possible solutions to the engineering problem and to ultimately justify the system chosen to implement as being the best of the alternatives. When choosing how to solve an engineering problem there are two main steps: 1 – to choose the best method to solve the problem, and 2 – to engineer that method to fit the specific situation. In layman’s terms, there are a lot of ways to skin a cat, but our job is to first decide what tool will make that job easiest, and then second to customize that tool to fit the grip of the one that uses it. Often in a project like this, the first step would be finished early in the project and most of the time would be spent on the second step, researching components, building a prototype, testing, and testing again. This was not the case for our project.

When the 2018 Labramani team met for the first time our problem seemed simple enough. The village wanted electricity so that their kids could study at night, they could work on crafts to sell at night, and so that they could charge small electronics. This was little different than the Japura project from the year before. The only twist was that Labramani actually has two locations – one closer to the road, and one higher in elevation. This meant that our system either needed to be ridiculously cheap in order to install it both locations or it needed to be portable. We also learned the villagers wanted to power blenders, a challenge that meant they needed a much beefier system than one to just power some dim lights and charge cell phones. With this, we considered wind power, solar power, a gravity system, and some combination of the three. With some early research we were able to remove wind power from the list, but solar power and gravity power remained in consideration all the way until the end. GravityLight is a company that makes lights that are powered by the rotational motion as a string with a weight on the end unwinds, similar to how a cuckoo clock works. Their lights are relatively inexpensive and would work well to provide light to the villagers, but they cannot power blenders. We considered their product as well as designing our own system that worked the same way. The solar system also had many alternatives to weigh. There are several companies that install solar systems in Peru, so working with a company was one option. A second option was to design our own system from scratch – choose panels, batteries, inverters, ect. that we could buy locally and install. The problem with both of these alternatives is that portability was still a challenge and power output was not quite enough for blenders. This is where the alternatives grew as we considered purchasing special blenders that would work on a lower power output and one of our team members worked to design a better blender as his senior project in hopes to solve our blender problems. We had reached this point early in the project and each member began researching all of the alternatives in order to quickly choose a system and dial in our design. As much as we wanted to get back data that showed clearly what option was best, however, the results of our research showed things were more tricky than we had assumed. The clear best way to skin this cat did not present itself and so we then dove into months of analyzing the alternatives.

Initially we split into two main teams, the power team and the appliance team. The power team’s job was to estimate consumption and calculate how much needed to be generated. The appliance team’s job was to research and test appliances (solar panels, blenders, ect.) and give that data to the power team for their calculations. We found ourself spending every meeting trying to balance consumption, generation, and cost. A solar system that did it all was too expensive and not portable, one that was cheap and portable had too dim of lights and couldn’t power a blender. Eventually we kept coming back to three main options, a company called Home 360’s system, a company called Zimpertec’s system, and our own system that some of our team members worked on designing. All three met the criteria of relative portability, light, and ability to power small electronics. We also considered supplementing the systems with GravityLights in order to have light independent of the solar system’s batteries.

In the end, we decided to go with the Zimpertec Solar Home System because of a few key differences that made it stand out. The Home 360’s system’s lights were too dim, and our own system was likely going to be too complicated for the villagers to operate, service, and repair. Zimpertec has a presence in Peru and can provide service and parts if the systems ever have problems which we cannot – especially because this is our last year of our five-year commitment to this area and by EWB rules, we must move on and leave this community independant of us, which is simply the only way to do humanitarian engineering in a sustainable way.