Feeding the Concrete Cow
Dryland forage sorghum to fuel
Texas biomass plant
By Dee Ann Littlefield
Editor’s note: Littlefield is a public affairs specialist with the
USDA Natural Resources Conservation Service office in
Henrietta, Texas.
n informal co-op of Texas farmers –
working in conjunction with their local
electric cooperative — is responding to
America’s growing demand for
renewable energy.
Midway, Texas, farmer Buddy Alders
and his power engineering partner, George King,
recently broke ground to build a biogas plant that will
be the first in the United States to use dryland forage
sorghum to generate a sustainable supply of electricity.
The sorghum will be grown on idle farmland.
Located near Leona, Texas, the Mustang Creek Biofuel
Plant is expected to be up and running by early 2010.
The bio-methane produced when the sorghum is
processed will be piped to generators that burn the gas
to produce 1 megawatt of electricity. Tex-La Electric
Cooperative, the generation and transmission co-op
that supplies power to Houston County Electric
Cooperative (HCEC), is negotiating a contract to
purchase the electricity, which HCEC will then
distribute to power about 400 homes in its nine-county
service area of east Texas.
“We are excited to be a part of this landmark
project,” says Mel Pinnell, HCEC manager. “Our goal
is to provide our customers with more efficient,
environmentally friendly electricity and this is a step in
the right direction. I think it is important to have a
diversified mix of energy sources, and this renewable
resource will have an added benefit for our members.”
Accidental revolutionaries
Alders and King never intended to help
revolutionize the energy industry; they just wanted to
find a more efficient way to farm and ranch. A life-long
conservationist, Alders went to the USDA’s Natural
Resources Conservation Service (NRCS) office in
Madisonville, Texas, to toss around some ideas with
local NRCS District Conservationist Floyd Nauls.
Alders was looking for some type of green energy —
possibly wind energy — to power his ranching
operation. Nauls suggested he visit Allen Smith,
coordinator of Post Oak Resource Conservation and
Development (RC&D), a branch of NRCS.
After meeting with Alders and King, Smith was
encouraged by their entrepreneurial spirit and went to
work to identify the best way to achieve their goals of
producing clean, green energy. Their combined
research led them to Germany, where they toured
biogas plants powered with feedstocks such as sorghum
silage and corn silage.
“These plants are often called a ‘concrete cow,’” Smith
explains. “The process mimics a cow’s digestive system. They
take in the food source, the bacteria breaks down the
cellulose and produces bio-methane.”
The plants appeared to be efficient, economically viable
and to offer a solution for Alders’ and King’s energy goals.
However, they didn’t want to use existing food crops as the
energy source for their electric plant. They had another idea.
Using idle cropland
In USDA’s 2002 Census of Agriculture, more than 21
million acres in Texas listed as cropland was not being
harvested. For economic reasons, many farmers had let their
fields go fallow and only grazed livestock on it. This fallowed
farmland has been deforested, and the rest has built up
organic matter and nutrients in the soil, making it an ideal
seedbed to plant a dryland crop such as hybrid forage
sorghum.
“We chose this variety of hybrid sorghum because it will
grow well in a wider variety of soils in a wider variety of
climates than other crops,” Smith says. “It also uses much less
water with less input costs.”
The group worked with MMR genetics, of Vega, Texas, to
find a hybrid forage sorghum plant that will increase
production volume and yield the most bio-gas.
“In this case, we want our cow to bloat,” jokes Smith.
“The more gas we can produce, the more efficiency we get.”
Unlike food crops grown for energy production, the
hybrid forage sorghum is a type of grass, so no valuable food
sources are used to generate the electricity.
Currently, the informal farmers’ co-op has committed
2,400 acres to grow sorghum for the plant. The farmers are
leasing the plant for now, with an option to buy it in the
future. The 1-megawatt plant will consume two tons of silage
per hour. Running 24 hours per day, seven days a week, the
plant will require 17,520 tons of sorghum annually.
On average, each acre will produce 12 tons of sorghum.
The extra acres in production will provide for crop rotation,
with two years of feedstock stored at all times. The silage will
be stored in silos at the plant site, where it will steadily feed
the “concrete cow” in the non-stop production process.
Feedstock flexibility
Smith explains that many feedstocks could be used in this
energy process. Ten years down the road, he says they may
run across something that works better. But for now, the
hybrid forage sorghum fits the bill.
“This is a landmark project for the United States and the
ag industry,” says NRCS Texas State Conservationist Don
Gohmert. “This has the potential to revitalize agriculture, as
millions of acres that could no longer produce profitable
commodity crops now have a new opportunity for income.
And the entire process is based on very sound soil, water and
crop production practices.”
Smith says that this system will build up organic matter in
the soil. Combined with more efficient tillage, such as strip
tillage, this is a sustainable system that will build the nutrient
profile of soils over time and reduce the need for commercial
fertilizers, he explains.
The greenhouse gasses emitted in the process will be
offset by their capture, and all of the byproducts produced in
the process will go back into the cycle or be used offsite. The
carbon dioxide produced from burning the bio-methane will
be captured, and – along with the introduced nutrients,
including poultry litter – will be used to grow algae, which
will produce biodiesel. The biodiesel will then go back to the
farmers who are raising the crops.
No water is used in the digestion production process. But
because, on average, silage is 67 percent moisture, water is a
byproduct. This water, with valuable minerals and nutrients
left in the digestate, will be applied back to the land.
Storm runoff water will also be captured and used for
plant sanitation and fire prevention. There are opportunities
to capture other byproducts, such as heat, which can be used
to heat water for hospitals, prisons and other facilities nearby.
Alders is also tapping wind energy for this project, which
was part of his original concept. Two 150-kilowatt windmills
were erected at the plant to improve the plant’s efficiency and
help maintain electric production.
Future expansion & co-op ownership potential
Based on the expected revenue from this first plant, an
economic analysis using the Regional Industry Multiplier
System predicts an additional 137 jobs and 14 businesses will
be created in the economic region from this project.
The original plan was to establish one plant, then expand
the operation to include five plants around the area.
However, investors say they see a potential for 50 plants in
central Texas. The basic concept is to continue to use outside
investors to build the plants, which would be leased to
farmers, who would have a chance to buy interest in the
facility and eventually own it.
Fuel for the plant in Leona will be provided by Alders and
King, working as an informal co-op (a minimum of three
members is required in most states to form a co-op), but they
envision future plants operating with fuel provided by a
formal growers’ cooperative which would meet the
requirements of Texas’ co-op law, also qualifying for funding
assistance.
If the number of plants does expand, the opportunity
would also exist for producer cooperatives to own and
operate the plants. In most cases, these planned cellulosic
bio-gas plants would likely sell electricity to rural electric coops.
Smith points out that with every single generation,
America is losing more and more farmers.
“This project could provide a new future for farming and
energy in America,” he says. “This is a crop that will actually
keep the next generation of farmers on the farm.”
