Aquion’s “Boxcar” Microgrid: Simulating Off-Grid Telecom Towers

by Aquion Team Member

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Just over a year back, we shared a blog post discussing our work on the Aquion “Boxcar,” a containerized energy storage demonstration that serves to approximate a telecom installation in an off-grid/weak grid application. At the time, we were testing out pre-production AHI batteries in the Boxcar. In September, Aquion replaced those pre-production batteries in the Boxcar with our new battery design – a production-intent prototype of the model that we will be producing at our manufacturing facility.

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Timeline of Aquion’s battery deployments in the Boxcar.

This blog post explores the challenges facing off-grid cellular towers and explains how Aquion Energy’s unique technology can be an effective solution for this large and rapidly growing global market.

Stationary Energy Storage for Telecom Applications

There are nearly 200,000 cellular towers in the US alone, and millions around the world. Some of these are tied to the grid, but an increasing number are being built in areas that have either a weak or unreliable grid or no grid at all. This is largely driven by the modernization of developing countries and the accompanying surge in cell phone use. For example, in India, there are currently 400,000 cell towers around the country – and nearly every tower lacks consistent, reliable access to the grid.

The towers require power to run both the telecom system electronics as well as the support systems for these electronics, mainly consisting of air conditioning. The power for these towers is traditionally supplied using a diesel generator. Diesel power, though inexpensive up front, requires costly and environmentally harmful diesel fuel, which becomes even more expensive after the costs of transporting it to a large number of dispersed, remote telecom installations.

A better solution is to reduce or completely replace the diesel use with batteries and solar panels. This is a perfect application for energy storage solutions like our Aqueous Hybrid Ion (AHI™) batteries that are optimized for long duration, daily cycling applications. Further, their long life and high heat tolerance make them advantageous over other energy storage options, such as lead acid, which must be frequently replaced in telecom applications – sometimes as often as once a year.

Aquion’s Telecom Demonstration

img_6487_0With the global telecom opportunity in mind, we created a proof-of-concept demonstration to help us better understand the application and display our capabilities to telecom tower operators. We used a 20-foot shipping container because it’s a similar form factor to the types of structures that currently house telecom system electronics in off grid locations. We installed solar panels on the roof, and inside the container we installed our battery stacks and a wide variety of inverters and charge controllers to test various configurations. To simulate the load, we used simple household appliances on timers and an always-on air conditioner.

The Boxcar uses 12 Aquion S10 battery stacks wired in parallel, replicating a single Aquion M100 module. This setup provides us with 18 kWh of nominal energy at a 20-hour discharge rate.

Running the Boxcar

We recently installed pre-production S10 stacks, shown in the picture above. The system has been cycling for the last several weeks. Below is a chart showing the system’s cycling over a weeklong period.

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You can see that the batteries maintain a fairly consistent voltage throughout their operation. We cycled at several different rates to simulate the different cycle rates that might be experienced in real-world installations.

Next Steps for this Installation

  1. Continued Operation and Testing. We now feel that we have enough data to replace the current beta-validated batteries with our S10 Battery Stack product. We will begin doing this over the next few weeks. We’ll publish another post in a few months with those results, so stay tuned!

  2. Optimization of system performance. This system demonstration helped us identify next steps in optimizing system-level performance. As an example, our batteries operate better at higher temperatures. In the current configuration, the system is cooled continuously by the Boxcar’s AC unit, so the batteries are not delivering as much capacity as they could.

  3. Productization of the solution. Though we are strictly a battery manufacturer and do not plan to integrate systems, we do think this is a viable system solution for the telecom market. As a result, we are partnering with a global system integrator to develop a turnkey telecom solution for developing markets.

Do you think solar and batteries are a viable replacement for diesel generators? Are you interested in reducing your diesel costs with AHI batteries? Download our free white paper for more! 

telecom batteries white paper

Topics: Off Grid, Commercial & Industrial

Written by
Aquion Team Member
This post was written by a member of the Aquion team.
 

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