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How to turn problem waste into high-value fuels

Neville Hargreaves, business development director at Velocys, discusses a process that may help to create and maintain a sustainable future by producing fuels from gas, biomass and waste.

The need for alternative, sustainable fuels has been recognised for decades. With fossil fuel reserves dwindling, solar, nuclear and wind energy will undoubtedly play a part in the UK’s energy mix. But over the last decade the use of waste as a source of energy has entered the collective consciousness.

The current scale of waste generation presents society with huge challenges: landfill charges are high, land use is coming under increasing pressure, incineration meets considerable opposition and not only is the export of waste becoming more costly, but many countries are seeking to minimise their waste imports and exports.

Alternative solutions are clearly needed.

The waste-to-liquids (WTL) process that transforms waste into high-value, clean-burning liquid fuels could form part of the solution. In this process waste is first gasified to produce a synthesis gas, which the Fischer-Tropsch (FT) process converts producing a range of hydrocarbons. These are upgraded using standard refinery technology to produce a wide range of finished products including ultra-clean fuels such as diesel and jet fuel.

WTL can deliver up to 70 per cent lifecycle greenhouse gas reduction over conventional fuels. Additionally, WTL-produced fuels have better environmental credentials than their petroleum-based equivalents – for example, they burn with significantly less particulates.

Until now technology limitations have meant that the FT process has only been deployed at vast scales. However, process intensification, as developed by Velocys, has meant that for the first time the process can be deployed at scales that match waste collection logistics and so can be used with waste as feedstock. Today, WTL could be used as a solution to both the growing waste problem and as a method of producing sustainable fuels.

In the UK, the landfill tax and fuel credits for road use currently make this country one of the more attractive for the development of WTL plants. Indeed, Velocys, Amec Foster Wheeler and other partners are involved with an initial engineering study to develop such a project that could use around 200,000 tonnes per year of post-recycled waste, destined for landfill or incineration, as feedstock. This is of the order of 10 per cent of the non-recycled waste generated annually in London. Therefore there are opportunities for multiple WTL plants in the UK.

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However, hurdles to implementation remain, particularly surrounding government policy.

For example, inconsistencies exist in biofuels legislation in the UK. At present, aviation fuels are not eligible for any of the incentives provided for road transportation biofuels, making it more difficult to build a business case to invest in UK aviation fuels projects than a “level playing field” approach would allow. Furthermore, the greater challenges and greater benefits of advanced biofuels (such as produced by WTL) relative to first-generation biofuels (such as those derived from sources like starch, sugar, animal fats and vegetable oil) are not adequately reflected in the Renewable Transport Fuel Obligations (RTFO).

WTL could deliver significant benefits to the aviation industry, which has the challenging target of reducing CO2 emissions by 50 per cent by 2050. The process is one of a very small number of options that could deliver a sustainable drop-in replacement to conventional jet fuel with an energy density high enough for use in aviation.

The technology needed to deliver these benefits is now a commercial reality. Velocys’ commercial reference plant, being developed by the joint venture company ENVIA Energy, is currently under construction in Oklahoma City, USA. This plant will use landfill gas (supplemented by pipeline natural gas) as input. Once in operation, on-site flaring of methane produced at the landfill will be significantly reduced.

Society and industry is waking up to thinking of waste as a potential resource, not just a burden. We at Velocys can picture a future that includes a small scale WTL facility at the waste processing facility of many large towns or city around the world. Companies like ours as well as national and local policy makers have a real opportunity to play their part in delivering sustainable change in how waste is disposed of and how fuels are made.