They can generate electricity from waste wood and biomass from agriculture. One such plant being planned for Wales will be able to power half their homes. Which sounds like a major wow, except that “virgin wood chips” might be used, and that’s not waste at all, but enormous numbers of trees being cut down. Plus, there’s the transportation problem. You have to get the fuelstock to the plant.
But even with all that, these plants won’t be using coal, and will burn quite clean, definitely an improvement.