Landfill gas is a sustainable energy source in that it transforms methane produced during the decomposition of organic waste into a source of renewable energy. Now an even more sustainable option is utilizing the waste carbon dioxide exhaust gases produced during this process to grow plants such as tomatoes. This creative approach has been used by a number of commercial tomato growers in North America and Canada.
By transforming this waste exhaust gas into a source of heat energy to heat up greenhouses, encourages plant growth, resulting in healthy productive tomato plants that produce tons of fruit for human consumption — the ultimate solution in terms of sustainability. Tomato greenhouses can be heated by heat recovered from electrical generators used in waste-to-energy projects at landfill sites, which are powered by methane gas collected from the landfill. By utilizing waste heat produced in waste-to-energy plants rather than traditional boilers that run on fossil fuels to heat a greenhouse, CO2 emissions can be significantly reduced. Furthermore, plants need carbon dioxide for growth, and by absorbing the carbon dioxide, the plants help reduce carbon emissions that would otherwise be released into the atmosphere.
Waste Heat Recovery Case Study
A project run by Modern Landfill in New York State in the US, in partnership with hydroponics greenhouse H2Gro — whose operation consists of 7.5 acres of temperature-controlled hydroponic greenhouses producing 10,000 tons of tomatoes a day — won an
Environmental Excellence Award for its innovative use of a source of alternative energy for meeting power demands and for sustainable crop production. The landfill gas collected at the landfill is converted to electricity which powers the landfill, and provides light and heat to the greenhouse where hydroponic tomatoes are grown. The surplus electricity is supplied to the power grid.
Landfill gas collected from Modern Landfill generates 5.6 megawatts of power which the company sells back to the New York power grid. Furthermore, waste heat that is generated when the gas is burned in the internal combustion engines is captured and recovered in the process. This heat, together with a small portion of the power generated, is then used to provide heat and light to H2Gro’s hydroponic greenhouse. The vine-ripened organically grown tomato fruit are grown commercially and sold to consumers for a profit.
Environmental Benefits of Waste Heat Recovery
The key environmental benefit of waste heat recovery from landfill gas projects is improved control over fugitive landfill gas emissions. Since implementing this project Model City Energy have cut their fugitive landfill emissions by 85%.
What makes this project stand out from other waste-to-energy projects is that not only is the landfill gas captured for energy production, the waste heat is also captured and used productively to enhance crop growth at the adjacent greenhouse. Its a win-win situation all round. The tomato growers (and consumers) benefit from healthier productive plants, the landfill owners benefit by reducing their fugitive landfill gas emissions, and the environment benefits by have less greenhouse gases being released into the atmosphere.
Although this partnership may seem rather strange, this type of project can be easily replicated. All that is required is an abundant source of low-cost fuel, sufficient vacant land nearby, a viable market for the end product, and the drive, determination and creativity to try something new.
Featured Image by Goldlocki at the German language Wikipedia [
CC-BY-SA-3.0], via Wikimedia Commons
