| “Plastic has more calorific value than coal or wood, and yet it is an irony that as a nation we burn coal every day to generate power and bury our waste plastic – which is a huge waste of energy.” |
Energy From Waste (EfW)
Our modern lifestyles generate an ever-increasing supply of waste, and this refuse is now being recognized as one of the greatest threats to our environment and to all life on earth. Because plastic comes from natural gas and crude oil, it makes sense to use it as an oil or coal substitute when it has finished its life as packaging etc. Plastics in effect borrow energy from the oil and gas stream, and then return it when used as a fuel in waste to energy conversion. This conserves the energy resources of the world, reduces greenhouse gas emissions, and therefore practices source reduction another way.
Unrecyclable plastic waste can provide a valuable source of local energy / electricity through Energy from Waste (EfW) - using established clean incineration technology - typical plastic waste contains some 18000 to 20000 BTU/lb versus fuel oil at around 21,000 BTU/lb. Implementing EfW can help with South Africa’s twin problems of diminishing landfill and the shortage of energy. EfW will not hinder increased recycling and there’s no credible evidence of EfW emissions affecting health. Energy from waste is accepted and proven for cleanly capturing the energy content of waste and replacing fossil fuels. It also reduces the creation of CO2 and methane.
An incineration process in which solid waste is converted into thermal energy to generate steam that drives turbines for electricity generators - waste-to-energy - offers an alternative technology for processing plastic wastes — particularly for those plastics that are unable to be recycled into other materials or products, such as contaminated medical waste, food packages, personal hygiene products and many other packaging products, such as confectionery wrappers. Modern waste-to-energy facilities are fitted with state-of-the-art pollution abatement systems and other environmental safeguards to effectively control the release of pollutants into the environment and ensure safe operation in close proximity to major population centres. Energy recovery involves the collection of solid waste to be burned at high temperatures to produce energy for power and heating. These facilities are commonly known as 'Waste to Energy' plants. The US
have some 121 waste-to-energy facilities in 29 states while Western Europe has close to 400 and Asia has more than 300.
About 70% of South Africa's energy needs are met from coal (including over 92% of electricity generation and about 30% of transport fuels). Although cheap by international standards, buying coal involves significant costs for energy-intensive processes. For example a single cement kiln can burn up to 180 000 tons of coal a year. Coal becomes more expensive the further you are from the coal mine.
According to a recent Environmental Impact Assessment Report into the feasibility of using waste (or ‘alternative fuels’) in a cement kiln, between 35 to 50% of coal can be replaced a year, depending on the composition of the waste. This means a cement company will avoid the costs of 40 000 to 90 000 tons of coal just for one of its cement kilns.
What's happening in the rest of the world?
Europe - 2008 at a glance |
Global production fell back in 2008 to 245 million tonnes from 260 in 2007 on the back of the financial crisis. The plastics industry experienced a dramatic 3rd and 4th quarter triggered by the economic crisis – more for those serving capital markets and less in daily consumables. Europe produced 60 million tonnes and remained a major region contributing about 25% of the global total.
The plastics industry – plastic producers, converters and machine manufacturers – employed 1.6 million people and many times more in industries depending on plastics for their business. The plastics producers and converters also contributed together 13 billion € in trade surplus to EU27 which helped to reduce the 242 billion € trade deficit for the whole industry in 2008.
Demand by European converters fell back 7.5% to 48.5 million tonnes in 2008.
Waste generation increased by just under 1%.
Both recycling and energy recovery increased to drive total recovery rate for plastics to 51.3% and disposal at landfill down to 48.7% thereby opening up a gap of 2.6%. Recycling increased by 5.4% over 2007, a lower year-on-year increase than in recent years, reflecting the severe impact of the economic crisis on this sector. Energy recovery increased 4.2% over 2007.
Seven of the EU Member States plus Norway and Switzerland recover more than 80% of their used plastics. These countries adopt an integrated resource management strategy using a range of complementary options to address each different waste stream with the best environmental and economic option.
Download The Compelling Facts About Plastics 2009 -
An analysis of European plastics production, demand and recovery for 2008, by PlasticsEurope
The recovery of energy from waste in Europe dates back 100 years. Today about 420 plants treat 64 million tonnes of municipal, commercial and industrial waste every year to produce electricity for 7 million households and heat for 13.4 million household. This also reduces CO2 emissions per year by 23 million tonnes; equivalent to taking 11 million cars off our roads.
The EU member states demonstrate very different “energy from waste” footprint and can be divided into three groups. Strong position for EfW Austria, Belgium, Denmark, Germany, the Netherlands, Sweden and Switzerland have demand and supply in balance and use EfW extensively.
EfW can be expanded - Ireland, Italy, France, Portugal and Spain offer market opportunities for growth but also market barriers.
Major growth potential - The Czech Republic, Greece, Poland and the UK all offer major growth opportunities which require very large investments.
The EfW route is technically, environmentally and economically fully proven. If Europe used the full potential of its residual waste stream, using the EfW technology, it could bring electricity to 17 million households and heat 24 million households.
Example Denmark
Denmark has the highest per capita production of both power and heat from EfW plants in Europe. The 30 EfW plants use 3.5 million tonnes of waste per year to produce 5% of the national need for electricity and 20% of the heat need. The district heating system today covers 53% of the heating market and this is planned to increase to 70% by 2030 by increasing the amount of waste treated in EfW plants to between 4.5-5 million tonnes per year.
|
| What happens inside a modern waste-to-energy facility? |
|
The energy value of municipal solid waste (MSW) can be recovered through waste-to-energy incineration. Modern energy recovery facilities burn MSW in special combustion chambers, then use the resulting heat energy to generate steam or electricity. This process reduces the volume of MSW to be landfilled by as much as 90 percent.
Energy recovery facilities are designed to achieve high combustion temperatures, which help MSW burn cleaner and create less ash for disposal. Modern air pollution control devices - electrostatic precipitators, dry and wet scrubbers, and/or fabric filters - are used to remove potentially harmful particulates and gases from incinerator emissions. |
| |
|
|
| How do plastics contribute to waste-to-energy incineration? |
|
Because Plastics are derived from petroleum or natural gas, they have a stored energy value higher than any other material commonly found in the waste stream. In fact, 2 kg of plastics can generate twice as much energy as coal and almost as much energy as fuel oil. When plastics are processed in modern waste-to-energy facilities, they can help other waste combust more completely, leaving less ash for disposal in landfills.
|
As this chart shows, plastics have a very favourable heat content compared with alternative fuels.
Energy Values |
Material |
Btu/pound |
Plastics |
PET |
10,900 |
HDPE |
18,700 |
Other Plastic Containers |
16,400 |
Other Plastics |
17,900 |
Rubber & Leather |
12,800 |
Newspaper |
8,000 |
Corrugated Boxes (paper) |
7,000 |
Textiles |
9,400 |
Wood |
7,300 |
Yard Wastes |
2,900 |
Food Wastes |
2,900 |
Heat Content of Common Fuels |
Fuel Oil |
20,900 |
Coal |
9,600 |
|
|
