Bagged Wood pellet price seem high, we can buy wood pellets bagged for £225/tonnes delivered. So gross energy is £225/4700kWh = £0.047, bulk wood pellets can be as low as £170/tonne depnding on how close you are to a supplier, so at best £0.036/kWh, presumably the leisure centre has a bulk wood chip store and is not using chips in bags, so comparing bagged wood pellets with bulk woood chip is not very representative. However, I install both wood chips and wood pellet, both are great systems