Glossary

  • Anaerobic Digestion:

    A series of processes in which micro organisms break down biodegradable material in the absence of oxygen to produce biogas.

 

  • Combined Heat & Power (CHP) plant:

    Used to convert the energy in the biogas to electricity (40%) and heat (45%), the remaining 15% is lost in the conversion process. In the case of anaerobic digestion about 20% of this heat and power is used parasitically (to run the plant) with the remaining 80% available for sale.

 

  • Combustion:

The burning of an organic compound in the presence of oxygen. Energy in the form of steam can be produced, which can be used directly in manufacturing processes, or on large projects can be turned into electricity by using a steam turbine generator.

 

  • DECC:

The Department of Energy and Climate Change

 

  • DEFRA:

The Department for Environment, Food and Rural Affairs

 

  • Digestate:

The liquid slurry left after the anaerobic digestion process. This material can be returned to land as it contains valuable amounts of Nitrogen, Phosphorous and Potassium as well as micronutrients such as Boron, Iron, Copper, Sulphates etc. Nutrients are considerably more bioavailable than raw slurry, meaning it is easier for plants to make use of the nutrients. Digestate is also less odourous than raw slurry. Digestate can be used straight from the digester, in which case it is called whole digestate. Alternatively it can be separated in to liquor and fibre. Digestate is not compost, although the fibre fraction has some similar characteristics.

 

  • European Union Emissions Trading Scheme (EU ETS):

The largest multi-national emissions trading scheme in the world. It is a major part of EU climate policy. The EU ETS currently covers more than 10,000 installations with a net heat excess of 20 MW in the energy and industrial sectors which are collectively responsible for close to half of the EU's emissions of CO2 and 40% of its total greenhouse gas emissions.

 

  • Feed-in Tariffs (FITs):

A renewable energy incentive that provides a guaranteed price for a fixed period to rewable electricity producers. The value of the FIT varies for different technologies. In the case of anaerobic digestion facilities of less than or equal to 250kW will be entitiled to 14p/kWh, facilities of between 250kW and 500kW will be entitiled to 13p/kWh and facilities of greater than 500kW will be entitled to 9.4p/kWh. The lifetime of the tariff is 20 years. Waste to energy plants will be eligible for either FiT’s or ROC’s but not both.

 

  • Gasification:

A process that converts carbonaceous materials, such as coal, petroleum, biofuel, or biomass, into carbon monoxide and hydrogen by reacting the raw material at high temperatures with a controlled amount of oxygen and/or steam which. The process produces a synthetic gas (syngas) which can be burnt in a CHP engine to make electricity and heat or used as a chemical feedstock for renewable liquid fuels.

 

  • Gate Fee:

A charge for the processing  of wastes. Fees are usually set with consideration to local competing treatments such as in-vessel composting, rendering and landfill and the potential energy output of the feedstock.

 

  • Landfill Allowance Scheme LAS:

The Scottish and Welsh equivalent to LATS. It sets targets and timescales for reducing the amount of biodegradable municipal waste (BMW) sent to landfill. Unlike LATS, LAS does not make a provision for trading allowances.

 

  • Landfill Allowance Trading Scheme (LATS):

An initiative by the UK government, through DEFRA to help reduce the amount of biodegradable municipal waste (BMW) sent to landfill. It provides the legal framework for the scheme and for the allocation of tradable landfill allowances to each waste disposal authority in England. These allowances will convey the right for a waste disposal authority to landfill a certain amount of biodegradable municipal waste in a specified scheme year.

 

  • PAS110:

The UK's standard for ensuring digestate produced from anaerobic digestion meets market needs and protects the environment.

 

  • PPC (Pollution Prevention and Control Regulations 2000):

Waste to energy plants fall under the control of PPC regulations. These regulations require the implementation of Best Available Techniques (BAT). This includes management and technical controls of the process to ensure that the environment is protected. Impacts such as noise, emissions to air, protection of habitats and the water environment are considered. A PPC licence will be required before the plant can be operated.

 

  • Pyrolysis:

Thermochemical decomposition of organic material at elevated temperatures in the absence of oxygen.  The process produces a synthetic gas (syngas) which can be burnt in a CHP engine to make electricity and heat.

 

  • RHI:

A payment for generating heat from renewable sources. The introduction of this is planned for April 2011 by the UK government and the value of the incentive is still be be set. The RHI will cover the injection of Biogas and syngas into the grid or for use as vehicle fuels, while clarification is need as to whether it will be payable for heat generated by CHP (as the FIT/ROC may be seen as incentive enough).

 

  • Renewable Obligation Certificates (ROC's):

A ROC is the green certificate issued for eligible renewable electricity generated. Different technologies attract differing amounts of ROC’s, gasification, pyrolysis and anaerobic digestion currently attract 2 ROC’s per MWh of energy production. ROC’s are traded and currently attract a value of approximately £45 MW/h. Waste to energy plants will be eligible for either FiT’s or ROC’s but not both.

 

  • Waste Incineration Directive (WID):

 A Directive of the European Parliament on the incineration of waste relating  to the standards and methodologies required by Europe for the practice and technology of incineration. The aim of this Directive is to minimise the impact of negative environmental effects on the environment and human health resulting from emissions to air, soil, surface and ground water from the incineration and co-incineration of waste.

 

  • WRAP (Waste & Resources Action Programme):

A government agency working in to help businesses and individuals reap the benefits of reducing waste, develop sustainable products and use resources in an efficient way