USNA Midshipmen Work to Produce Renewable Energy from Everyday Waste

By MCSN Kaitlin Rowell

A class at the U.S. Naval Academy is working to convert what we think of as everyday garbage into usable energy, a project that supports the Navy’s energy independence goals and potentially changes the way we view waste.

The average American throws away five pounds of trash each day which adds up to 258 million pounds of waste each year according to the Environmental Protection Agency (EPA). In 2014 more than 89 million tons of municipal solid waste (MSW) were recycled and composted, the highest percentage recycled in the U.S. to date. Unfortunately, even with these efforts, 136 million tons of MSW still ended up in landfills.

 But it turns out, through emerging process in which this waste is collected and process, landfills could be a valuable source of renewable energy.

Patrick Caton, a USNA Mechanical Engineering professor, and the students in his Waste-To-Energy Conversion class are attempting to determine just how much energy can be harnessed from everyday waste.

“This class is about engineering systems that can turn anything that we might consider to be waste into a usable energy source,” said Caton. “We try to take a broad view of waste. The obvious thing people think of when they hear waste is trash, but very quickly I hope students learn to view that more broadly.”

They first collect and sort waste into different categories. They then estimate how much energy each category of trash can produce by weighing it. The samples are then sent to an external lab for further testing, where they will be analyzed by first drying the waste to determine its moisture content, and then put into an oven where its mass loss is measured as it burns. With this information, the lab determines how much ash is produced as well as how much energy is released by measuring the amount of carbon, hydrogen, oxygen, sulfur and nitrogen. The lab will then send the results back to the students to compare with their original estimates.

“We waste a lot of energy with trash,” said Midshipman 1st Class James Shadow. “Most people don’t do a whole lot of composting, and you can get a lot of energy out of that. You can get a lot of energy out of the trash that’s just sitting in the trash cans. That’s kind of enlightening.”

Using trash as an energy source is a gateway to a healthier environment and allows us to limit our use of fossil fuels, as well as reduce the cost of living.

“One of my goals for my students is to leave this class with a mindset … where the things that may have before been considered unusable or just complete waste actually have value,” said Caton. “I think that's a really important part of managing our energy going forward as a people, as an earth.”

Another project the class is working on is experimenting with food waste from King Hall, the dining facility for the Brigade of Midshipmen.

Midshipman 1st Class Scott Davids explained that by taking the food waste, grinding it up, adding some small bacteria to it and removing the presence of oxygen, an environment is created forcing the bacteria to produce gas. That bio-gas is about sixty to seventy percent methane.

The goal of this is to take decomposing food waste and collect methane to be used for energy.

“The benefit of these projects is getting midshipmen involved and showing opportunities for energy generation in the future,” said Davids. “This is something that is not only really applicable here to learn about in class, but also something that could play a part in our roles in the Navy.”

In 2009, then Secretary of the Navy Ray Mabus issued several goals directed at transforming the Department of the Navy’s (DoN) energy use. Among them were to increase total energy consumption from alternative sources to fifty percent by 2020 and reduce petroleum use in the commercial fleet by fifty percent by 2020.

This project provides yet another possible method for achieving those goals.