Project Overview

Alterna’s Mission

Alterna on their mission:

Alterna is a Center for Innovation and Entrepreneurship based in Quetzaltenango, Guatemala. Our mission is to develop technologies and build local businesses that satisfy basic needs and provide economic growth opportunities for the Guatemalan people in an environmentally sustainable way.

One of their major projects are micro-hydro plants in rural areas:

Two million Guatemalans live without access to electricity. The vast majority of these people live in rural areas. Expansion of the national grid to the areas that are left unserved is increasingly difficult due to geographic constraints.

Guatemala is also a country with great potential for utilization of hydroelectric power. The extensive rainfall and mountainous terrain of the country provide optimal conditions for generating electricity with water power.

http://www.alterna-la.org/en

http://www.alterna-la.org/en/projects/microhydro

Our Mission

Alterna currently has no good ways to monitor how much power these micro-hydro plants produce, because off-the-shelf systems designed for ultra-high current environments are expensive. Measuring power generation is useful both to understand the efficacy of these installations and because it is prerequisite to applying for carbon grants which can offset the costs of development. Therefore, we prototyped a circuit based on the open-source Arduino platform which measures single-phase AC power coming out of the installation, logs it to an SD card, and transmits daily SMS status updates over a GSM network. The circuit can handle household voltages (~240V), currents up to 100A, and costs around $200 (and as little as $100 when produced at scale).

Carbon Offsets

Becoming accredited to sell carbon offsets is not a trivial process and having information on kWh generated is only one part of it. Nevertheless, organizations like ClimateTrust exist to help organizations through the bureaucratic steps of the process, but they can’t do anything without data, so we feel confident that this device will be an important part of offsetting micro-hydro costs with carbon offsets.

The U.S. Department of Energy Clean Energy Application Center authored a report on selling carbon offsets, which you can read here.

Specs In More Detail

Intended Purpose

• Easy to use power measurement device
• Cheap to make
• Able to monitor current and voltage on 1 phase system
• Logs data to an SD card
• GSM connectivity provides two functionality:
• Sends an SMS if the voltage drops for an extended period
• Sends a daily “power collected” SMS with the power generated during that day
• Flexible design allows for reprogramming and hacking

Intended Users

• Engineering graduates and other workers with basic technology fluency.
• Designed so that it can be manufactured relatively easily.

Power Measurement Specifications

• Nominal voltage is 220V. Maximum we’ve seen was 225, minimum 219. There may be brief moments (around half a second or less) when it is much lower, down to 150V, when an extra heavy load is switched on.
• Nominal frequency is 60 Hz. Minimum 59, maximum 62.5.
• Single Phase AC.
• Current varies significantly depending on the season (water flow). Max in the rainy season is approximately 55A. Right now it’s about 30A. Dry season production may drop down as low as 15A, but we aren’t sure on that yet.