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Could gasification power cars?


Ian Williamson

New and improved energy from waste technologies such as advanced gasification are going to be essential if many countries are to address their considerable waste problems. Advanced gasification can reduce the amount of waste going to landfill, as well as maximise the renewable energy produced.

Even though it is by no means alone, the UK is a classic example of a country that is benefiting from the use of Energy from Waste technologies.

According to Eurostat, the EU data agency, the UK has ranked consistently among the top five EU countries in terms of the amount of waste sent to landfill. And of the 150 million tonnes of waste being buried in the ground, 50 million tonnes comes from homes.

Worryingly, the UK's landfill space could be running out. The Local Government Association believes that there could be little remaining space for landfill as early as 2018. In addition, the UK Government is under pressure to meet the EU's Landfill Directive, which demands a 65% reduction in waste going to landfill by 2020; meaning the UK will have to find a way to reduce – or redirect – around 100 million tonnes of waste.

Despite being an established technology, the initial incinerator technology used for converting waste to energy was never universally popular in the UK. Early incinerators produced harmful emissions and the leftover ash from burning waste often ended up in landfills. Although incineration technology has progressed, other technologies such as Advanced Gasification have been developed which provide additional benefits; advanced gasification can turn waste into energy with higher efficiencies, a reduced carbon footprint, with fewer by-products ending up in landfill.

One of the largest advanced gasification projects for renewable power generation planned for the UK is being proposed by Air Products. The 49MW advanced gasification plant planned for the Tees Valley – in the Northeast of England – is one of the largest new applications of a proven gasification technology. This plant will turn hundreds of thousands of tonnes of waste into energy, will produce a significant amount of renewable, baseload power, and this will be done while reducing the carbon footprint per unit energy of the waste.

"Like many other renewable energy projects, the Tees Valley and potential future plants will be dependent on the outcome of the Government's Renewable Obligation banding review, and Electricity Market Reform consultation."
 

There are other benefits of this technology too, such as the possibility in the future of running zero emissions vehicles from low carbon hydrogen produced by the plant.

Like many other renewable energy projects, the Tees Valley and potential future plants will be dependent on the outcome of the UK Government's Renewable Obligation banding review and Electricity Market Reform consultation. Without certainty around financial support, it will be challenging to bring this innovative new technology to the UK.

The Tees Valley facility

Air Products is in the process of progressing the planning and environmental applications. If everything goes to plan, work on the plant will begin at the end of 2011, with the plant up and running by 2014.

Working with a local waste management company, the Tees Valley plant will use a mix of household, commercial and industrial waste from the local area that has been sorted to remove recyclable materials. The proposed facility will process between 300,000–350,000 tonnes of waste every year, and the energy produced would be capable of powering the equivalent of 50,000 homes.

Why is advanced gasification unique?

Advanced gasification is one of the best technologies currently available to convert waste into energy. It is more energy efficient than most, has lower associated carbon emissions, and most of the by-products from the process are usable, with the potential for minimal material going to landfill.

Advanced gasification uses plasma torches, which reach temperatures well above those of conventional technologies. The waste is therefore not burned, but instead is broken down into some of its most basic components – as a gas mixture made up of mainly carbon monoxide and hydrogen (also called syngas).

The syngas is cooled, cleaned-up and scrubbed to remove particulates, and then fed into gas turbines to generate electricity. Unlike incineration, advanced gasification does not leave an ash residue that has to be disposed of. Instead, the by-product from this type of gasification can be used as road aggregate, and most of the by-products of the process have some beneficial use.

"Advanced gasification can generate renewable energy at a local level, reduce waste going to landfill and even produce renewable hydrogen for low carbon transport."
 

The carbon footprint of the advanced gasification plant compares favourably with other energy from waste technologies, as well as landfilling. Preliminary findings from Air Products suggest that the advanced gasification technology produces roughly 40% less carbon – for the same amount of energy – as incineration.

Decentralised baseload renewable energy

It is not just the desire to cut waste, however, which makes energy from waste technology attractive. Countries around the world face a considerable challenge around energy security (in the UK for example upwards of 20% of energy generating capacity is expected to be shut down in the near future.

Energy that comes from waste helps to compensate by feeding the grid with baseload power. The constant supply of waste means that, unlike many other forms of renewable energy which for example rely on the sun shining or the wind blowing, the energy generated will be continuous. Air Products hopes to build a number of such advanced gasification plants around the UK, and this locally-generated renewable energy would serve to help secure the UK's energy supply.

Hydrogen transport

Advanced gasification provides an additional strength which differentiates it from other Energy from Waste technologies – the potential to produce hydrogen.

In order to meet carbon reduction goals, the UK must address emissions from road transport. Moreover, air pollution in the UK's cities necessitates action to prevent harmful pollutants from vehicle exhaust fumes.

There are two main alternatives to conventional fuels for powering low carbon cars – electric and hydrogen vehicles – and many people say the best option is going to be a vehicle that combines the strengths of both.

The potential to produce renewable hydrogen thus makes advanced gasification a very interesting prospect in creating a low carbon transport infrastructure in the future.

Once the syngas has been produced from the waste, it is possible to separate a stream of hydrogen from the syngas. This hydrogen can be used to power zero emission transport – for example it could run a fleet of hydrogen buses or potentially power the trucks that collect the waste. Air Products estimates that the Tees Valley plant could easily produce enough hydrogen to power about 1000 buses every day.

"Once the syngas has been produced from the waste, it is possible to separate a stream of hydrogen from syngas."
 

For hydrogen transport to become a reality in the UK, low carbon hydrogen infrastructure needs to be created around the country. This project, and others like it, can create self-sustaining hydrogen infrastructure around which both local power and transport systems can be built.

Reducing landfill

The construction of advanced gasification plants at strategic points around the UK would allow a dramatic reduction in the amount of waste that goes into landfill. Working with waste companies which sort waste and remove the recyclable materials as Air Products will be doing in Teesside, will allow the reduction of waste further.

Bringing this next generation technology to the UK is currently costly, and is only possible because of the current Government incentive regime. At the moment, advanced gasification qualifies for Renewables Obligation Certificates (ROCs). For companies like Air Products to make large financial investments in the Tees Valley and future plants, there needs to be certainty around Government support.

The Government's desire to reform the current electricity market to create more certainty for renewable energy products is laudable, but the new regime needs to be quickly installed, accepted as robust by the markets and it must, of course, continue to support advanced gasification at current levels.

Advanced gasification can generate renewable energy at a local level, reduce waste going to landfill and even produce renewable hydrogen for low carbon transport. Moreover, it is efficient and dramatically reduces the carbon footprint of waste. Tees Valley will hopefully be the first of several advanced gasification plants in the UK if the economic and legislative environments are right. And this could also provide a blueprint for other nations.


About:

Ian Williamson is Hydrogen and Bio Energy Systems Director at Air Products and President of the European Hydrogen Association.


Renewable Energy Focus, May/June 2011.

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Bioenergy  •  Energy efficiency  •  Energy infrastructure  •  Energy storage including Fuel cells

 

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