This story here is not one I thought I would have the opportunity to write. After 20 months of focusing much of my climate and climate policy reporting on burning wood pellets for energy, I wandered into a side event at the 25th United Nations climate summit featuring the CEO of Drax, the United Kingdom’s largest weed-pellet-burning power plant.

Not coincidentally, the moderator of the event told the audience packed into the UK pavilion that there would not be time for questions — before the program started, and even though it wrapped up five minutes early. In other words, he didn’t want to make any of his guests uncomfortable by having to take difficult questions about the scientific reality of burning wood instead of coal to generate electricity.

But as soon as the program ended, I walked over to the riser as the Drax CEO was preparing to leave, introduced myself and asked him if he had a few moments for questions. He did. He was candid, slightly defensive, and clearly proud of his company. I also was able to balance the CEO’s opinions and remarks with the knowledge and insight of one of the world’s top climate scientists on the issue of wood pellets and energy.

The result is one of the most compelling and dramatic stories I’ve written from the six UN climate summits I’ve covered since Lima, Peru, in 2014.