The Enviropark proposed for Hirwaun will have distinctly separate technologies that are linked together using well established process integration engineering.
It is this linking together that produces energy production efficiencies that enable an Enviropark to be classed as an energy producer.
Fuel Preparation Area
The key technology employed is the Fuel Preparation Area or FPA for short. The FPA is essentially a sophisticated sorting and separation system, often termed a MRF or Materials Recycling Facility.The primary purpose of the FPA is to separate incoming feedstocks into four categories. The incoming feedstocks are derived primarily from the commercial sector and is made of the types of waste typically seen outside shops and offices although there will be a smaller quantity of construction and demolition waste and even smaller quantities of residual household waste. Much of the household waste produced in south Wales is now treated at the incinerator at Trident Park in the centre of Cardiff. None of the feedstocks that will arrive at Enviroparks are classed as hazardous and most will be found in public places prior to collection and processing.
The first category is recyclates - and by recyclates we mean metals, glass, plastics - in fact anything that has a value and can be offered for further processing off-site. It is our longer term goal to further process recyclables on site to reduce waste miles and produce useful products. This can be done in the 'High Energy User' building that will offer continued employment opportunities.
The second category is a fuel specifically manufactured in the FPA to make our gasifier as efficient as possible. This is often referred to as Refuse Derived Fuel or RDF. This differentiates Enviroparks from incinerators which typically burn 'raw waste'.
The third category is a very high energy value fuel which will be transported off site to be used in cement kilns to make cement. This is often referred to Secondary Derived Fuel or SRF and it is more suitable for the production of cement as it replaces a proportion of fossil fuel which would otherwise be used.
At Enviroparks both RDF and SRF are highly specified fuels.
The fourth category separated is aggregate, which is typically stones and bricks which are sent offsite for further crushing and grading for use in construction.
When Enviroparks was first conceived there was a large amount of food waste arising in household waste. Since the Environment (Wales) 2016 Act organic food wastes are now separated at the kerbside and occur in low volumes. On the positive side this means that feedstocks arriving at the Enviroparks site don't smell badly. As a result of this policy of kerbside collection being successfully implemented in Wales, Enviroparks has no plans to build the Anaerobic Digestor in the near future.
The residual feedstocks, whilst having no residual value, will still have a calorific or fuel value produced as described above.value. Calorific value is a measure of the energy content of a material. We can release that energy in the form of a synthetic gas by exposing this feedstock to high temperatures in a controlled atmosphere which limits the amount of air in the vessel. This gasifies the feedstock converting it from a solid state to a gaseous state in the absence of flame. This is a very similar process by which Town Gas was produced in Gas Works before the arrival of North Sea Gas.
This synthetic gas is then used to produce steam which drives a turbine generating electricity which is transmitted to the National Grid. Enviroparks is one of four companies in the UK to recently qualify for the Governments renewable energy subsidy called CfD of Contracts for Difference.
High Energy User
To complete the concept of the Enviropark we invite a company to co-locate with us. This improves our electrical and thermal efficiency and we are then able to supply 'green' electricity and heat at greatly reduced rates to this company.
This approach encourages regeneration at the Enviropark and the surrounding area and leads to further employment.