From waste to wealth: transforming greenhouse waste into energy

Posted on Wednesday, December 20th, 2017

Animesh Dutta

Guelph – When Animesh Dutta ponders the problems of the world, he lands on energy security, food security and climate change. The University of Guelph researcher’s latest project holds promise for addressing all three.

As professor and director of the Bio-Renewable Innovation Lab in the School of Engineering, Dutta focuses on taking waste from farms or food processors and finding the best solution to convert it into renewable energy that will maximize the economics.

When he started working on bioenergy, Dutta saw the benefits of creating a renewable source of energy that didn’t interfere with food production.

“The economics don’t seem to be there for using feedstock for bioenergy,” he says. “You have to purchase the raw product and farmers want a price for their biomass crop that is higher than the value of the bioenergy it makes.”

So Dutta began looking to other sources of raw product needed to create renewable bioenergy and wondered about the waste generated from greenhouses and food processing industries. They use a lot of heat and generate green waste (vines) that farmers/processors must pay to dispose of. On the plus side, greenhouses provide a great model to develop a closed loop system for energy production and use.

“I looked at what greenhouses could do to use their own farm waste to generate heat,” says Dutta. “But food waste by nature is very wet and we needed a more efficient way to process it.”

Drying waste requires a lot of energy and defeats the purpose of creating an efficient new bioenergy source.

That led Dutta to develop an innovative approach to ‘cook’ the waste in water with a hydrothermal carbonization (HTC) reactor – creating a carbon product (like biochar) and a biogas that can be used similar to natural gas as an energy source.

The greenhouse industry is ideal for this new process to create green energy because it comes complete with the source of the raw product (waste) and the need for the end product (energy).

To test the process, Dutta is working with a greenhouse operation and manufacturer in Leamington, ON to create a closed-loop system where the farm can use their own plant waste to create a bioenergy-based heat source on their operation.

“This system addresses climate change, biogas production, waste water management and soil health,” says Dutta.

To show the greenhouse industry how the HTC process works, Dutta and his team are building a demonstration pilot in Leamington that will be open and operational in 2018.

Dutta’s work dovetails well with the provincial government’s 2016 Resource Recovery and Circular Economy Act (Bill 151) designed to create markets for recovered resources.

“Waste is a resource looking for an opportunity,” says Dutta. “We need a more efficient way to turn waste into energy, and the goal with this research is to expose those new opportunities for green waste.”

Dutta is looking to the food processing sector as the next industry that can benefit from his HTC process.