Duncan is a consulting industrial chemist who specialises in petroleum (refining, including, oil, condensate and gas fractions) and energy developments (coal, lignite and co-produced electricity). Duncan specialises in petroleum processing that maximises the value of the raw feedstock to produce value added products including speciality products such as helium, ammonia and urea. Duncan also is a renowned expert of coal-to-liquids and gas-to-liquid system design. He has provided consultancy services in the energy, petrochemical and legal sector on all aspects of coal and hydrocarbon processing, energy utilisation and technology. Recently Duncan has undertaken a review of the technical, environmental and economic factors of new synthetic methane production from non-export coal; that work is ongoing.
Duncan has a strong interest in promoting energy security for Australia, and in 2012 joined Mike Clarke as a co-author of a paper presented at the ASRC Forum, Canberra, titled Energy Security in Australia. Duncan is the principal of Duncan Seddon & Associates (DS&A P/L) and a member and director of OPA P/L.