As petroleum resources are finite, it is imperative to use them wisely in energy conversion applications. Plastics, a petroleum-based product, are widely used in manufacturing disposable products and have created a solid waste issue. Due to their abundant supply, and given their high energy content, their use for power generation is of technological interest. Direct combustion technique produces considerable amounts of health hazardous airborne compounds. Thus, an alternative technology is proposed herein to further address our increasing energy needs and, at the same time, utilize our waste plastics streams in an environmentally-benign manner. More specifically, a multi-step process/device is proposed to accept post-consumer plastics, of various types and shapes, and generate an easily-identifiable form of energy as a final product. A demonstration device has been constructed to convert the internal energy of plastics into clean thermal energy and, eventually to electricity. Indirect combustion technology is integrated in this device, together with automatic feeding system, to achieve a controllable clean conversion of waste plastics into electricity.