Even with the most efficient processes in place, over-ripened fruit and vegetables are still a source of food waste. Ideas to counteract the issue may include turning them into jams and conserves, quick sale at discounted prices, donation to food banks, or using them as animal feed. Soon, farmers might have an extra option at hand: using over-ripened tomatoes to generate electricity.
Researchers at South Dakota School of Mines & Technology in the USA, led by Venkataramana Gadhamshetty, have found a way to tap into tomato chemical energy to extract electrons and produce energy. As part of a recent pilot project, the team tested a biological-based fuel cell that used tomato waste sourced from agricultural harvests in Florida. Thanks to a new electrochemical device built at the school, the team was able to break down the tomatoes and release electrons contained therein into the fuel cell which then converts them into electricity.
The pilot generated 0.3 watts of electricity from ten milligrams of tomato waste. Although the power output from their mini reactor is small, the team expects scale-up and further research to increase output by many orders of magnitude.
The results of this project could have a positive impact on areas such as waste management as well as supplying low-cost alternative energy sources. In Florida alone, some 396,000 tonnes of tomato waste is generated every year – an issue that has yet to be efficiently dealt with by the state. The potential is therefore huge for this latest development to greatly reduce decomposing waste entering landfills, emitting methane and polluting water sources, and to help power up infrastructure. Indeed, according to the researchers' own estimation, there is enough tomato waste in Florida to power up Disney World for 90 days a year.
Beyond decaying tomatoes, the chemical energy found in other tomato products - such as sauces, ketchup and cooking products - can also be tapped into to generate a cheap, alternative source of energy.
“A lot of tomato waste is produced with a lot of chemical energy sitting there. We wanted to see if we could use this waste as a source of electrons,” Gadhamshetty said.
The project joins the ranks of a number of other initiatives looking to harness power from organic matter like soil, plants and even leaves in order to provide more environmentally-conscious sources of energy.
From pizza, to salads, to sauces, it seems the ubiquitous tomato is not just a source of flavours and a nutrients powerhouse - antioxidant and cardiovascular tonic properties have been attributed to the lycopene it contains, for example.
This latest research shows that at a strike, the humble tomato could become our ally in the production of renewable energy, the reduction of food waste and in our battle to limit greenhouse gas emissions.
You can watch the research team present their findings in this video: