Education

Where there is waste there is energy

 By Nicholas Newman

In a consumer society, most people do not view trash and human waste as a problem, except perhaps when they struggle to close the lid on their bin or their toilet is blocked. Typically, each UK household produces an average of over 1 metric ton of rubbish a year, which amounts to about 31 million metric tons for the UK as a whole, an amount which is reduced by a 44.6 percent recycling rate. Sweden performs marginally better achieving a recycling rate of 49.8 percent. According to Yale University research, Americans are the most wasteful, recycling just 21.4 percent of their trash. The resultant constant supply of decomposing rubbish makes landfills the third-largest human-created source of methane emissions in the United States…

Increasingly, dumping unwanted rubbish into a large hole in the ground or waste into a river, lake or the sea is becoming less acceptable. Governments in Europe have introduced Landfill taxes and fines for non-compliance with waste management legislation in an effort to reduce and manage rubbish and waste disposal. However, rubbish and waste can be turned into energy. Incinerating one metric ton of rubbish can provide power for 500 hot baths, 3,500 hot showers or 5,000 hours of television.

There are many different types of waste, whether from households, industry or agriculture, that can be converted into heat or power. Excluding all types of recycling, about 70 percent of rubbish collected is combustible.That includes paper, cardboard, biodegradable waste, textiles, plastics and more. Indeed and surprisingly, common household waste has a similar calorific value to that of oil shale. Burning landfill and sewage gas to provide fuel for power plants converts waste into cash. Anaerobic digestion of agricultural waste yields renewable energy, cuts farmer’s bills and creates a source of income. Alexander Marshall, Group Marketing & Compliance Director at Clarke Energy notes that, “in many countries feed-in tariffs or additional levels of support for the generation of electricity from renewable energy from waste plants is becoming commonplace.“

Most people do not view trash and human waste as a problem

The current market

The Waste-to-Energy market was valued at around $20.8 billion in 2015 and is set for ‘take-off’ as waste companies recognize the economic opportunity of converting waste into renewable energy. For example, in the Danish city of Aarhus, the council is selling the power and heat produced from waste to fund the budget for vital council services. In America, companies including Apple and General Motors are using existing landfills as a source of renewable energy. A case in point is General Motors (GM) assembly plant in Lake Orion, Michigan, home to GM’s Chevrolet Bolt EV. The plant sources 54 percent of its electricity from a nearby landfill gas power plant cutting its power bill by $1 million a year. In Africa and perhaps the United States, sales of anaerobic digesters are likely to increase, while those in the UK, are expected to fall following reduced subsidies for renewable energy, “claims Marshall.

Turning rubbish into energy

Incineration is viewed as a good way to solve a waste problem. It is also a way of generating energy. In Paris, three Waste-to-Energy plants heat half the city including the famous Louvre museum where the famous Mona Lisa is on display. One of these plants, the Saint Ouen Incinerator processes some 600,000 metric tons of household waste every year, and supplies heat to Paris district heating system and power to the French grid operated by EDF.

Incineration is viewed as a good way to solve a waste problem

Turning landfill waste into energy

A common practice is to collect and burn the methane gas given off by landfill to fuel a nearby power plant. For waste disposal companies this is a ‘no brainer’ since it reduces the chance of a methane leak and earns additional revenues. In some cases, gas-to-liquids technology is applied, turning methane into industrial chemicals including petrol for sale. The United States Environmental Protection Agency (EPA) estimates that about 0.67 megawatts of electricity can be produced from every 1 million metric tons of solid municipal waste.

How Edmonton's old dump powers 4,600 homes

Turning sewage gas into energy

Sewage plants are highly energy-intensive. Aeration, pumping, water and wastewater treatment processes 24/7 all year long account for 25 to 40 percent of the municipality’s electricity consumption states Mads Warming, Global Segment Director for Water & Waste Water, Danfoss. Not surprisingly, sewage operators have been looking at ways to cut their power bills. Apart from improving energy efficiency, the only other option is to produce their own power.

Self-generation of power is the promising new business model for sewage plant operators. Anaerobic digestion of bio-solids in sealed tanks yields biogas or methane, a renewable fuel and suitable feedstock, for a Combined Heat Power plant explains Marshall. A striking early adopter is the Marselisborg Wastewater Treatment Plant in Aarhus which, according to Mads Warming, “now produces 40 percent more electricity than it needs and 2.5 GW of heat for the district heating system without adding external organic waste or carbon.” This excess energy is enough to power the region’s drinking water supply and wastewater treatment facilities.

SEE MORE: Energy emerging from waste by Michelle Leslie

about the author
Nicholas Newman
Freelance energy journalist and copywriter who regularly writes for AFRELEC, Economist, Energy World, EER, Petroleum Review, PGJ, E&P, Oil Review Africa, Oil Review Middle East. Shale Gas Guide. https://nicholasnewman.contently.com/