Re: Ethanol Question

Jerry, you once said that cane is burned before being harvested in
Hawaii. I have been searching for the answer in Brazilian ethanol
production. Here is what I found:

"Electricity from bagasse

Sugar cane plant (Saccharum officinarum).Sucrose accounts for little
more than 30% of the chemical energy stored in the mature plant; 35% is
in the leaves and stem tips, which are left in the fields during
harvest, and 35% are in the fibrous material (bagasse) left over from
pressing.

Part of the bagasse is currently burned at the mill to provide heat for
distillation and electricity to run the machinery. This allows ethanol
plants to be energetically self-sufficient and even sell surplus
electricity to utilities; current production is 600 MW for self-use and
100 MW for sale. This secondary activity is expected to boom now that
utilities have been convinced to pay fair price (about US$10/GJ or
US$0.036/kWh) for 10 year contracts. The energy is especially valuable
to utilities because it is produced mainly in the dry season when
hydroelectric dams are running low. Estimates of potential power
generation from bagasse range from 1,000 to 9,000 MW, depending on
technology. Higher estimates assume gasification of biomass,
replacement of current low-pressure steam boilers and turbines by
high-pressure ones, and use of harvest trash currently left behind in
the fields. For comparison, Brazil's Angra I nuclear plant generates
600 MW (and it is often off line).

Presently, it is economically viable to extract about 288 MJ of
electricity from the residues of one tonne of sugarcane, of which about
180 MJ are used in the plant itself. Thus a medium-size distillery
processing 1 million tonnes of sugarcane per year could sell about 5 MW
of surplus electricity. At current prices, it would earn US$ 18 million
from sugar and ethanol sales, and about US$ 1 million from surplus
electricity sales. With advanced boiler and turbine technology, the
electricity yield could be increased to 648 MJ per tonne of sugarcane,
but current electricity prices do not justify the necessary investment.
(According to one report, the World bank would only finance investments
in bagasse power generation if the price were at least US$19/GJ or
US$0.068/kWh.)

.

Relevant Pages

  • Re: Ethanol Question
    ... I have been searching for the answer in Brazilian ethanol ... "Electricity from bagasse ... Sugar cane plant.Sucrose accounts for little ... distillation and electricity to run the machinery. ...
    (soc.retirement)
  • Re: Ethanol Question
    ... I have been searching for the answer in Brazilian ethanol ... "Electricity from bagasse ... Sugar cane plant.Sucrose accounts for little ... distillation and electricity to run the machinery. ...
    (soc.retirement)
  • Re: Strategies for CO2 reduction
    ... > Some alternative forms of standby are biomass and hydro. ... Of course hydro plant can be started in minutes, ... to produce about 8KW of heat and 4KW of electricity. ...
    (uk.environment)
  • Re: The ethanol nightmare has arrived!
    ... would the plant have a continuous duty cycle or would ... Will massive amounts of waste heat be generated requiring large amounts ... dependent upon electricity. ... that simply can not be allowed to become the sole source of power. ...
    (rec.aviation.piloting)
  • Re: I Saw a Guy on TV the Other Day Peddling the Oil Shale Myth
    ... Stated cost /KW of electricity produced by coal vs nuke is very close ... Those loons could ... Seco nuclear plant, the site was big, sunny, and had the requisite ...
    (soc.retirement)