Plastics - A Source of Energy

Material recovery is by no means the only way to recycle plastics. Another option is to recover their thermal content, providing an alternative source of energy. An average typical value for polymers found commonly in household waste is 38 mega joules per kilogram (MJ/kg), which compares favourably to the equivalent value of 31 MJ/kg for coal.

This represents a valuable resource raising the overall calorific value of domestic waste which can then be recovered through controlled combustion and re-used in the form of heat and steam to power electricity generators. Successful ventures in this field include plants, such as a major incinerator in Edmonton, North London which produces steam to power an electricity turbine. The electricity is then sold on. Waste containing plastics can also be reprocessed to yield fuel pellets, which have the added advantage of being storeable.

It's sometimes claimed that incineration of municipal waste poses an environmental problem in the shape of atmospheric pollutants. Although the potential is there, modern incineration techniques ensure that actual emission levels are kept within internationally accepted safety limits. In fact, several countries, such as Sweden, Germany and the Netherlands, have recently affirmed their confidence in incineration by announcing plans to expand their existing capacity.

Waste to energy is a highly efficient way of recovering the inherent energy of plastics. One yoghurt pot contains enough energy to light 60 watts for one hour. One carrier bag if burned can provide enough energy to light a 60 watt bulb for 10 minutes.

Source: British Plastics Federation