Thirty-two years ago, my interest in the oil price shocks of the 1970s took me to the University of California at Berkeley to study energy. That same year the Liquid Fuels Trust Board was established in New Zealand. The Board clearly saw lignite as the country’s future source of transport fuel. However, because lignite is poor quality coal, extracting energy from it creates particularly high emissions of carbon dioxide. My concern about this is not new. Twenty years ago I co-authored a report called Transport fuels in New Zealand after Maui – lignite on the back burner.

It now looks as if lignite is making its way to the front burner. Two companies, state owned enterprise Solid Energy and the L&M Group, are proposing to mine lignite in Otago and Southland and convert it to diesel. In addition, Solid Energy is proposing to make two more products from lignite: the nitrogen fertiliser urea, and briquettes (made by drying out lignite into a better form of coal) primarily for export. Using lignite for generating electricity is another possibility.

The foundation of this report is a set of carbon footprint calculations for these four uses of lignite – diesel, urea, briquettes, and electricity. These calculations are presented in as open and transparent a manner as possible. I ask those who may question these calculations to be equally transparent.