One Man’s Trash is Another Man’s Renewable Energy

The practical benefits of an organic product do not necessarily end when it goes down the drain or into the trash. In fact, there is quite a bit of useful energy left in the items we discard. Using heat exchanges, anaerobic digestion technology, and waste-to-energy facilities, the projects here showcase important bioenergy technology that is being used right now to drive down traditional energy costs and increase renewable energy installed capacity worldwide.

Gateway (Theater) to the Future Uses Waste Heat to Lower Energy Costs

The Gateway Theatre is a 50,000 square foot multiuse public theater in Richmond, BC. In 2013, the city approved the use of a sewage wastewater recovery system at the theater to help meet its greenhouse gas and reduced energy consumption goals.  There was a wastewater treatment plant near the theater, which made the project feasible.

Image: Gateway Theatre in Richmond, BC. Credit: City of Richmond, BC.

Essentially the system, supplied by International Wastewater Systems, takes raw sewage, processes it and then extracts heat to process fluid. The fluid is then supplied to the building’s low-temperature heat loop. The company said that up to 250 gallons per minute of raw sewage can be pumped through its SHARC system.

The project was meant to reduce natural gas use and provide a renewable heat source for the facility. Additional retrogrades were performed, such as replacing a boiler and couplings and a building envelop improvement. The new technology and upgrades were projected to reduce natural gas use at the facility by approximately 45 percent, annual operating costs by $10,800 and drop GHG emissions by 50 tons.

The system was completed in September 2013. The capital cost for the heat recovery system was $55,000 and when the design, labor, additional upgrades and replacement were added up, the total project cost was just under $200,000 with about half of that met through two government grants. Based on the first two years of operating costs, the avoidance savings mean that the project should have a payback of six years. It is expected to last for 25.

Image: The Sewage Shark system installed at the Gateway Theatre in Richmond, BC. Credit: International Wastewater Systems.

What is the potential for this type of technology? The U.S. Environmental Protection Agency estimates that about 385 billion kWh of energy is sent down the drain each year in the form of waste heat.

Leeks, Onions and Maize Power Allpress Farm and the Grid

While farmers understand the how compost closes the loop on the organic growth of their crops, they may not be quite as savvy when it comes to harvesting the energy that is created when those crops decompose. That’s where companies like EnviTec Biogas, a Germany company with a subsidiary in the U.K., comes in.

Allpress Farms grows leeks and onions for supermarkets plus wheat, maize and sugar beets for various other uses.  The family-owned farm employs about 100 people and is run by brothers Nick and Patrick Allpress.

In 2014 the Allpress brothers created Horseway Energy as a way to diversify revenue streams. Horseway uses biogas technology to supply power to the grid.  The feedstock for the biogas is a 50-50 mix of maize and waste from the leeks and onions. EnviTec Biogas UK installed the 500-kW system, which today generates almost 12,000 kWh of electricity each day.  The digestate, which is the leftover portion of the waste after it has been processed, goes back to the crops as fertilizer.

Nick Allpress said the total cost for the project was £2.5 million [US $3.4m], which was financed through personal loans and private equity.  Allpress receives 3.8 to 4.3 pence [US $0.05 to 0.06] from the grid for each kWh of energy he generates but the largest portion of the revenue from the project comes from the feed-in tariff (FIT). “The FIT is a substantial contributor the project income and is guaranteed at 14.63 pence [US $0.20] per kWh, this is also index linked for 20 years,” he said.

Image: The storage tanks at Allpress Farms. Credit: EnviTec Biogas UK.

The company said the project is expected to pay for itself within eight years of operation.

A Landfill-based Alternative to Natural Gas

In shale-gas rich Pennsylvania, there is a lot of natural gas being fracked and pumped through pipelines to take advantage of the robust natural gas market. With so much natural gas flooding the market and rendering gas prices cheap, it comes as little surprise that a market for renewable natural gas is having a hard time emerging. With the help of Renewable Natural Gas credits (RNGCs) developed by The Energy Co-op, however, that emerging renewable natural gas market may get a little boost.

Renewable-energy minded consumers who live near the Marcellus Shale and may be opposed to fracking, now have a “solution-oriented option” available to them, according to Clay Bedwell, Director of Energy Operations at The Energy Co-op. The Energy Co-op has just patented the first RNGCs, which it sells to natural gas users to offset their use of traditional natural gas with renewable natural gas that comes from landfills.

“We are looking to have a similar effect as RECs. The real objective of the RNGC is to add value to those organizations that are productively using biogas in a way that offsets pipeline gas,” explained Eric Kravitz, Director of Business Development. He added: “Just like RECs add value to people operating wind farms or solar farms, RNGCs are a financial incentive for people to operate and further develop landfill gas operations.”

Landfill gas has a lower BTU count and can be used directly by industrial users who have modified equipment that can run on it.

Landfill Gas To Power in Florida

At the end of an 18-mile transmission line, an Orlando Utilities Commission (OUC) substation in St. Cloud, Fla., receives power from a 9.8-MW CB&I facility that is powered by landfill gas from Progressive Waste Solutions. The gas comes from decaying garbage and would otherwise be destroyed by burning off in a flare.

HR Green designed the facility and specified all of the gas treatment, compression, and generating equipment, which consists of six Caterpillar 3520C low-BTU fueled generator sets. The gas chilling and compression equipment was provided by Landfill Gas Specialties, a subsidiary of CB&I.

Image: Exterior intake fans at CB&I’s waste-to-energy facility in Florida. Credit: HR Green.

According to Douglas G. Tholo, President of HR Green’s Energy Business Line the total project budget was $18,700,000, which included the electrical interconnect with OUC.  HR Green’s portion of the total budget was $13,900,000 and the project was brought in under budget at a total project actual cost of $14,292,145.

Skip the Landfill Altogether

In late February, energy-from-waste (EfW) company Covanta released its 2014 sustainability report that showed that the company has helped produce 9.8 million MWh of clean energy and reduced waste going to landfills by 20.7 million tons.

One of the ways it has reduced landfill waste is through its zero-waste-to-landfill initiative, which assists companies in finding ways to reduce materials consumption, re-use materials, recycle, compost and use anaerobic digestion and then recovering whatever waste is left through EfW facilities.

In September 2014, Rochester-NY based Diamond Packaging achieved zero manufacturing waste-to-landfill status with Covanta’s help.

Zero manufacturing waste to landfill is defined by Diamond Packaging as 100 percent landfill waste diversion through a combination of recycling and energy recovery solutions. In Diamond’s case it accounts for all waste related to the manufacture of folding cartons, including paperboard, plastic, metal, industrial waste, and regulated waste, with the exception of construction and demolition (CD) waste.

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Jennifer Runyon has been studying and reporting about the world's transition to clean energy since 2007. As editor of the world's largest renewable energy publication, Renewable Energy World, she observed, interviewed experts about, and reported on major clean energy milestones including Germany's explosive growth of solar PV, the formation and development of the U.S. onshore wind industry, the U.K. offshore wind boom, China's solar manufacturing dominance, the rise of energy storage, the changing landscape for utilities and grid operators and much, much, more. Today, in addition to managing content on POWERGRID International, she also serves as the conference advisory committee chair for DISTRIBUTECH, a globally recognized conference for the transmission and distribution industry. You can reach her at

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