The Rural Voice, 1979-08, Page 4Methane production
on the farm
It's not practical yet
BY ALICE GIBB
It's a frightening scenario - the OPEC countries decide to
bring the Western nations to heel with their major weapon, oil.
The price of gas and crude oil skyrockets and suddenly farmers
in Canada find they're victims of their own technology. Tractors
and combines sit rusting in fields because the cost of fuel is
prohibitive. Farmers suddenly have to find alternate energy
sources that are readily available, reducing the size of their
farming operations in the process.
Whether or not the oil war ever reaches the state pictured in
that scenario, the popular press is already preaching that the
farm population has to start looking at alternate energy sources -
and they have to start looking now. One of the methods being
touted the most in magazines and back -to -the -land publications
is the production of methane gas from animal and vegetable
wastes, materials found in most farmyards. How close are we to
producing methane gas on the farm?
Prof. Jack Pos, an agricultural engineer at the University of
Guelph, and the man in charge of a research project developing
an on-farm methane production plant, said if a farmer came
through his office door one day and asked him for help in
designing a methane digester system, Mr. Pos' advice would be
"forget it l "
The engineer said right now the cost of producing methane gas
is more than the value of the gas produced. In other words,
despite pressure from the agricultural community, methane gas
production on the farm as an alternate -energy source, just isn't
economical yet.
Donald Presant, agricultural engineer working with the
extension branch of OMAF, has been quoted as saying the same
thing.
"At first glance, the combination of large quantities of manure
and a rising cost for all types of common energy sources appears
to favor farm production of methane gas. Unfortunately, the
production of methane from manure is not nearly as simple or
economical as some writers suggest. Many examples of methane
use on farms come from tropical or semi -tropical countries where
labour is cheap, the climate is warm, and there are no other
sources of energy. None of these conditions applies in Canada,"
Mr. Presant said.
FACT OF LIFE
In countries like India, Taiwan and Africa, methane production
has been a fact of life for many years. In India, for example, the
PG. 2 THE RURAL VOICE/AUGUST 1979
Gobar (Hindi for cow manure) Gas Research Station was
established some years ago and by 1975, more than 2500 farm
digesters were in operation. However, many of the digesters
simply produce enough gas to fuel a small cooking unit to meet
the needs of the farm family.
To produce methane gas from animal manure. manure must
be turned into liquid, fed into a digester (see diagram) that is
tightly sealed so no oxygen can get into the system and the
temperature inside the tank must be kept at a constant 35 o C.
The gas is removed from the digester and the leftover sludge can
be piped out and spread on farm fields in place of commercial
fertilizer.
Jack Underwood, an agricultural engineer who teaches at the
Centralia College of Agricultural Technology said in North
America, most activated sludge sewage plants already have
digester systems. Methane gas is the end product and some use
the gas to run compressors in their system, while other plants
simply let the gas escape into the atmosphere.
Methane, like many gases, is combustible and highly
explosive when mixed with air. For example, a home built over a
former landfill site in London, Ontario explo ded a few years
ago, and other homes in that area still have to be monitored for
further methane gas buildup.
While digesters don't seem difficult to design, Jack
Underwood maintains the popular press has oversimplified the
building of a digester system on the farm.
Both he and Prof. Pos agree that on-farm research into the use
of digesters is needed. Prof. Pos points out in the West, farmers
and the government have co-operated to finance the Biomass
Institute in Winnipeg to do alternate energy research. Both men
also caution however, that digester systems can be costly and
time-consuming.
Jack Underwood said, "We have to know what the problems
are (in methane gas production) so we have the technology at bay
when we feel we can go on with it on a practical basis."
However, he feels the price of fuel and of a farmer's time has to be
a lot higher than it is now for on-farm methane production to be
an economically feasible proposition.
Jack Pos admits planning an on-farm digester system has been
a "design challenge". In the first year of the research program,
which is also looking into solar energy uses on the farm, his team
came up with a conceptual design for a farm -scale methane gas
digester. The second phase included drawing up detailed