Electric Power & Utilities/Wood burning electrical generation
I work at a manufacturing plant. I once spoke to someone at a different plant in another state that indicated to me that they used their scrap wood to burn and generate electricity (they made wood trim). They said that they even generated enough electricity that some was 'sold back' to the electric company.
What is the feasibility of this idea? We don't work with wood products at my facility, but I see a LOT of scrap wood come through and I see extensive scrap wood piled up even at facilities adjoining us. I do home improvement work as a side job and see a lot of wood being dumped into the landfills on a regular basis and as a ecologically minded person, it bothers me to see this 'energy' going to rot. I think it wouldn't be a concern of 'cost' to get a lot of fuel.
I realize that creating such a system would cost a lot of money, but is it being done? How is it done? And what is the rate of return / payoff?
Hi Roger -
There is absolutely no "technology" obstacle to the burning of waste wood (and biomass in general) in a boiler to make steam to drive an electrical generator. This is widely practiced in the U.S. and around the world, and has been for a very long time. Most waste incinerators in the U.S. use boilers and generate electricity.
The three real obstacles are:
A) NIMBY - Not in My Back Yard - the understandable resistance of people to having a new power plant located near their residences (near the sources of waste). These days it is nearly impossible to get a permit from local authorities to build a solid fuel (waste) burning plant. Neighbors do not want exposure to the extensive truck traffic delivering waste, or to the smells of the garbage which would ideally be included in the waste stream. Locating the plant well away from populated areas is the obvious solution to NIMBY, but it does increase the waste transport distance, thus making it more expensive for the city to get rid of the waste or for the plant to buy the waste "fuel." In theory, one could sort out the wood waste and and haul it to an existing coal-fired electric power plant that is equipped to burn it with the coal, but this requires people taking the trouble to keep wood waste separate from other trash, and other people being willing to collect it, etc. Some cities do this, but most do not.
B) Adverse Economy of Scale - Almost all utility owned coal-fired power plants are immensely larger than any waste wood power plant could hope to be. The waste plant size is limited by the amount of waste economically available on a constant basis. The economic advantage of the large plant is that a kWh of electricity from a large new steam power plant costs less than that from a small new steam power plant. For example, the cost to build a new steam plant that makes 100 megawatts (MW) of electricity is nowhere near 10 times the cost a 10 MW plant … therefore the cost per kWh of electricity from the larger plant is significantly less. It could even afford to pay more for its fuel (coal) than a waste wood plant, and still generate lower cost electricity. So the only investors who will build a new waste wood plant are those few who can get really cheap waste fuel on a continuous basis, in an area where more new power supply is needed and competing coal-fired or gas-fired electricity would be too expensive for some reason, and/or where the state gives a subsidy payment to renewable or waste fuel derived electricity.
C) Shale Gas - With the sudden abundance of low cost natural gas from the fracking of shale in the U.S., and given that a high efficiency gas-fired combined-cycle power plant would be much cheaper to build, even in a small size, than a small new waste wood-fired steam power plant, then, in the absence of a state subsidy, no one is going to build anything but gas-fired power plants for the foreseeable future.
We could go on and on, talking about solar and wind and hydro power economics vs waste wood-fired economics. And we could talk at length about the relative greenhouse gas climate change effects of each as compared to coal and gas plants, etc, but let's leave those equally important matters to another day.
Good luck !