How is this Bio-mass power plant plausible?

In summary: This biomass power plant proposes to generate 29 MW of electricity by burning biomass to heat a fluid (likely an ammonia-water mixture) and turn a turbine. This would require two boilers consuming 150 tons of biomass per day at a heat value of 5200 btu/lb. Even if all the heat energy was converted without loss, it would only produce 3.43*10^12 J/day. The company claims an efficiency of 73%, which is difficult to achieve without a temperature difference of around 850 C. This may be above the creep value of the turbines. It is surprising that the company missed this basic calculation and it may be worth discussing with superiors before proceeding with the project.
  • #1
How is this Bio-mass [basicaly just a steam power plant] power plant plausible?

It says it is going to supply 29 MW of electricity by burning biomass to heat some fluid (I suppose an ammonia-water mixture, but I really do not know) and turn a turbine (Something like a Rankine cycle I guess). It also says that is will use two boilers capable of consuming 150 tons a day while getting 5200 btu/lb.

29MW*1 day=2.51*10^12 J.

Now, if they turned 100% of that heat energy into mechanical and then electric energy without loss, it would only come out to 3.43*10^12 J/day.

They are claiming they will get this thing to 73% efficency. The problem is, even a carnot engine would need to operate with a temperture difference of around 850 C to achieve this, and since they have no chance of making a system that can match a carnot engine, I would imagine they would really need something like a 1400 C difference.

Isnt that above the creep value of anything they could make the turbines out of?

What am I doing wrong?
Physics news on
  • #2
I agree with your calculation, it seems a little suspicious.
  • #3
diazona said:
I agree with your calculation, it seems a little suspicious.

All the documentation I have seen is really only in the conceptual phase, but the company that submitted it to us to make a bid on it (They want approximate costs of construction so they can start trying to sell it) has already looked like they put a fair amount of work into it (made some isometric drawings and whatnot), which makes me hesitant to think they missed something so basic.

Anyways, I am just an intern, so I wanted to get someone elses input before I asked my boss about this, no reaosn to look like a complete fool on my first week!
  • #4
:smile: well... I hope someone else responds to check this because I also think it's rather surprising that they would have missed something basic like that. Unless they are trying to pull a fast one on your company. And if they are, imagine how much your superiors would love you if you call them on it and save the company from entering into an impossible project ;-) (although I guess it'd be the kind of thing you'd want to bring up discreetly first)
  • #5
Coal-fired power plants (500 - 1000 MW) are roughly 33 - 35% efficient; about 10,000 btu per kilowatt-hour. Gas-fired power plants may be as good as 8,000 btu per kilowatt-hour (40 - 42% efficient).

1. How does a bio-mass power plant work?

A bio-mass power plant uses organic material, such as wood chips, agricultural waste, or animal manure, to generate electricity. The organic material is burned in a boiler to produce steam, which then turns a turbine to generate electricity. The leftover ash from the burning process can also be used as a fertilizer.

2. Is bio-mass power a renewable energy source?

Yes, bio-mass power is considered a renewable energy source because the organic material used to generate electricity can be replenished through natural processes, such as planting new trees or growing crops. This makes it a sustainable energy source that does not deplete finite resources.

3. How does a bio-mass power plant compare to other types of power plants?

Compared to traditional fossil fuel power plants, bio-mass power plants emit significantly less greenhouse gases and pollutants. This makes them a more environmentally friendly option for generating electricity. However, they may require a larger land area and have a lower energy output compared to other types of power plants.

4. What are the potential benefits of using bio-mass power?

Besides being a renewable and environmentally friendly energy source, bio-mass power can also provide economic benefits. It can create jobs in the agriculture and forestry industries, as well as in the construction and maintenance of bio-mass power plants. It can also reduce dependence on imported fossil fuels, leading to energy independence for a country.

5. Are there any concerns or drawbacks to using bio-mass power?

Some concerns with bio-mass power include the potential for deforestation if the organic material is not harvested sustainably. There are also concerns about air pollution from burning the organic material. However, these concerns can be mitigated through proper regulations and technologies, such as using emission control systems.

Suggested for: How is this Bio-mass power plant plausible?