Assessing economically viable carbon reductions for the production of ammonia from biomass gasification

Paul Gilbert,Sarah Alexander,John Brammer,Patricia Thornley

doi:10.1016/j.jclepro.2013.09.011

Paul Gilbert, Sarah Alexander + Show 2 more

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https://doi.org/10.1016/j.jclepro.2013.09.011

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Abstract

Greenhouse gas emissions from fertiliser production are set to increase before stabilising due to the increasing demand to secure sustainable food supplies for a growing global population. However, avoiding the impacts of climate change requires all sectors to decarbonise by a very high level within several decades. Economically viable carbon reductions of substituting natural gas reforming with biomass gasification for ammonia production are assessed using techno-economic and life cycle assessment. Greenhouse gas savings of 65% are achieved for the biomass gasification system and the internal rate of return is 9.8% at base-line biomass feedstock and ammonia prices. Uncertainties in the assumptions have been tested by performing sensitivity analysis, which show, for example with a ±50% change in feedstock price, the rate of return ranges between -0.1% and 18%. It would achieve its target rate of return of 20% at a carbon price of £32/t CO, making it cost competitive compared to using biomass for heat or electricity. However, the ability to remain competitive to investors will depend on the volatility of ammonia prices, whereby a significant decrease would require high carbon prices to compensate. Moreover, since no such project has been constructed previously, there is high technology risk associated with capital investment. With limited incentives for industrial intensive energy users to reduce their greenhouse gas emissions, a sensible policy mechanism could target the support of commercial demonstration plants to help ensure this risk barrier is resolved. © 2013 The Authors.

Highlights

The Copenhagen Accord (UNFCCC, 2010) recognises that to avoid experiencing high levels of climate change, as described by the Intergovernmental Panel on Climate Change (IPCC, 2007), requires greenhouse gas concentration in the atmosphere to stabilise
This study considers the potential use of biomass to reduce greenhouse gas emissions from fertiliser production and in particular ammonia production, as a step change measure to decarbonise the industrial sector
With its reliance on the transport sector to deliver the imported biomass and high electricity usage during gasification and ammonia synthesis, the results indicate that there is more future potential to decarbonise the biomass gasification system

Summary

Introduction

The Copenhagen Accord (UNFCCC, 2010) recognises that to avoid experiencing high levels of climate change, as described by the Intergovernmental Panel on Climate Change (IPCC, 2007), requires greenhouse gas concentration in the atmosphere to stabilise. This study considers the potential use of biomass to reduce greenhouse gas emissions from fertiliser production and in particular ammonia production, as a step change measure to decarbonise the industrial sector. Many renewable energy sources are not amenable to the provision of high temperature heat, for example wind, tidal and wave resources are more amenable to direct conversion to electricity, yet it is key for process plant operations that the fuel is fixed carbon, storable and available continuously. With this in mind, biomass represents a possible low carbon fuel source for the production of ammonia. It is essential to carry out a full and comprehensive TEA and carbon accounting of the entire system to ensure that fuel switching will have the desired results

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