Little gem

The plant is known by its commercial name Scarborough Power Ltd and is a joint venture between GEM, BB Newco Ltd and Yorwaste Ltd. The project was chosen to be part of the New Technologies Demonstration Programme by Defra and will process 25,000 tonnes per annum of unsorted municipal solid waste (MSW).{mosimage}

GEM's process can be described as 'flash pyrolysis'. It is the chemical decomposition of feedstock by intensive heat in the absence of oxygen also known as "destructive distillation" or "cracking".

GEM views all kinds of materials as potential fuels for renewable energy including MSW, commercial waste, agricultural waste, sewage sludge, rubber crumb, waste oils, foodstuffs, rendered animal by products, bio-crops, and wood. It has developed a process to give the highest energy conversion efficiency from waste materials.

The GEM Converter module has been designed to convert 1.5 tonnes per hour of suitable feed material into gas on a
continuous basis. Prepared fuel is continuously fed into the GEM Converter via an auger mechanism, at an optimum rate. Once inside the converter, heat instantly penetrates the particles, efficiently cracking them into a clean synthetic gas.

To optimise efficiency, great care has been taken in the design of the system to eliminate air entering the process and to prevent produced gas escaping. The gas is retained within the converter for up to 50 seconds to maintain the heat transfer and maximise efficiency, it is then cooled and cleaned before use in a power island.

The GEM pyrolysis process has no emissions to atmosphere and is a sound environmentally friendly alternative to other technologies such as incineration.

At the plant in Seamer Carr, 25,000 tonnes of 'black bag' (MSW) waste is prepared into a suitable fuel by the Wastec
segregation system. This process removes recyclables and inert materials and creates a flock RDF (refuse derived fuel). It is then shredded, granulated and dried to a moisture content of five to eight per cent. The pre treatment of the waste increases the conversion efficiency. The material is then delivered to the GEM unit, where it is converted into a synthetic gas. This gas is cooled and fed to a Deutz engine (supplied by Edina) to generate electricity. The GEM unit will produce circa 1.8 MWe of electricity and 2.5 MW of heat per hour. The electricity will be exported to the national grid and is eligible for Renewable Obligation Certificates (ROCS).{mosimage}

The plant will be increased in capacity to 75,000 tonnes by 2010 to take it from a demonstration facility to commerciality.

There are many advantages of the GEM technology as a solution to waste disposal and power generation. The need for renewable energy and a reduction in landfill is a high priority for the world. The EU has stipulated that it wants to reduce the amount of waste going to land fill to 75 per cent of the 1995 level by 2010, 50 per cent of the 1995 level by 2012 and 35 per cent of the 1995 level by 2020. In addition, the EU has stated that it wants member states to provide 20 per cent of its energy production from renewable sources by 2020. At present, the UK only contributes circa 5 per cent. GEM's technology can be an important component in helping achieve these aims. In addition, due to the need for preparation of waste before it enters the GEM converter recycling targets can be easily met, as recyclables can be removed before conversion. GEM technology is based on the 'proximity principal', meaning that it is well suited to being built near waste streams and communities (due partly to the zero emissions from the pyrolysis process).
Also, the fact that a GEM converter is a standard size (modular) means that increases in waste can be easily accommodated by installing more converters. The ethos of GEM is 'little and often'. Plants can be built to varying sizes
and to different waste streams that are appropriate to the surrounding supply. The GEM technology has the advantage of needing to process less tonnage of waste than incineration to be commercially viable. An incinerator usually requires at least 250,000 tonnes of waste per annum, which often means that it needs to be collected from a wide area to reach these targets. This increases distances travelled to dispose of waste and therefore increases green house gasses from transportation. A GEM plant can be viable at a much lower tonnage and can be positioned close to the waste source. This reduces transport emissions and is more appropriate in relation to the UK emission strategy. The UK has signed up to reduce green house gas emissions by 80 per cent by 2050. The fact that the pyrolysis process has no emissions and the proximity principle is a beneficial way to help achieve this.

The GEM Gas Conversion technology presents an elegant solution for some of the major environmental challenges facing the world today. Atmospheric pollution, waste management, sustainable energy and resource use are embraced globally as significant problems associated with social and industrial development of the modern world. Topics such as climate change, non renewable fossil fuel use, landfill, poor resource management and sustainability
need addressing today to protect tomorrow.

GEM aims to penetrate all levels of the waste market over the next few years and sees Scarborough Power as a fantastic facility to demonstrate its innovative technology. The company has gained much interest globally and sees its technology as a key player in the future of waste management and renewable energy production.