The NY Times has a surprisingly enlightened piece on the fairly esoteric topic of co-firing:
Power Plants Try Burning Wood With Coal to Cut Carbon Emissions
In the article, the reporter points out some of the opportunities and challenges facing coal-fired power plants. Keep in mind that until recently, fully 50% of domestic power was generated from coal combustion, and even now, it's something like 45%. (Coal has come into disfavor with utility companies due to both low cost of "natural" gas, and increased costs of emissions compliance.) The potential is huge; the challenges are equally huge.
This is a topic I'm pretty familiar with, having done research into various alternative energy schemes over the years. I'll summarize and provide some nuance and opinion below the orange flame.