In essence, black liquor is a residue that's left over after the pulping process. They extract all sorts of chemicals, and it's basically the sludge that comes out at the end of the process.
It is a fuel. There are future applications for it. It's incredible. You can break it down into more chemicals and you can actually do chemical refinery. Europe is really tacking those on to the pulp mills.
So there is an enormous amount of potential that could come out of that product. But in its purest form, you can just burn it. For a long time, pulp mills have been generating their own energy from it. So they will use that to create the steam and that will turn their turbines, which will generate the energy to create the pulp.
Basically any pulp mill that has it coming out the other end is using it in one form or another and they've been doing it for decades.