Rubbish, really. Peat is thousands of years’ worth of decaying vegetation, animals and moss which have evolved into layers; a bog if you will. Peat’s substance varies; some bogs are woodier, whilst other peat is more watery. A peat bog grows by 1mm every year, so just a metre thick bog is 1000 years old.
When peat is harvested, it’s cut up into small sloppy slices of ‘sod’, stacked in pyramids, and left to dry. Before you know it, well, 2-3 weeks later, you have yourself some tough peat bricks, which contain more energy than coal. Peat fires are an ancient Scottish tradition; the stuff is so compact that it burns piping hot for ages.