Autumn 2017 EN

English Issue
Biogas Journal
| Autumn_2017
Miguel Angel Perales de la Cruz, who planned the
design, financing and construction of the plant for
the cooperative.
Alex Eaton, a U.S. citizen, established Sistema
Biobolsa seven years ago.
Violeta Bravo de Sepúlveda is from Mexico. She is
working for a project of the Brandenburg University
of Technology (BTU) Cottbus-Senftenberg and the
Center of Research and Technological Development
in Electrochemistry (CIDETEQ) in Querétaro, Mexico.
“Lagoons are inexpensive, but they are also
like black boxes that are difficult to check”
Violeta Bravo de Sepúlveda
about four euro cents per kilowatt hour. Cruz Azul pays
the cooperative more than twice that much. The state
supports so-called clean energies only through investment
incentives, subsidy programmes and, starting in
January 2018, with Clean Energy Certificates. However,
these clean energies also include modern gas and
nuclear power plants.
For this reason, the agreement with Cruz Azul is a good
deal, at least during times when there is a great supply
of Nopal. The plant, however, which has been providing
electricity since September 2015, is supposed to make
money primarily by producing solid and liquid fertilizer.
It will be made in a hall built especially for this purpose.
Laboratory experiments and field trials certify its effectiveness.
What’s missing, however, is a sales market
for the organic fertilizer. Now most of it is used on the
cooperative’s own fields.
The plant concept of Sistema Biobolsa also focuses
on fertilizer production and using its own power production.
“Eighty percent of the area of this dairy farm
is fertilized with the residue from their biogas plant”.
Alex Eaton points to the seven lagoons with their sunbleached
foil covers, inflated by the pressure of the
methane gas. To regulate the pressure, old automobile
tires are situated on the foil. The plant, 280 cubic metres
in size, is located at Rancho Sinai near Zumpago
de Ocampo, northeast of Mexico City. Eaton, a U.S.
citizen, established Sistema Biobolsa seven years ago.
He walks out onto one of the foil covers and starts to
rock back and forth. If the lagoon gurgles, it means that
only liquid is fermenting there thanks to a separator
that separates the solids out.
Maintenance is lacking for small plants
Eaton’s team constructed this plant with a motor available
on the local market. This way, the total costs of the
plant were just about 15,000 euros (converted from pesos).
Sistema Biobolsa covered two-thirds
of the costs with an interest-free loan. The
Ministry of Agriculture contributed the other
third. There are budgets for these sorts
of investment support. However, experts
complain that these monies are not always
used in a meaningful way; too often a
scattergun approach is applied. Many small
biogas plants are not functioning because
the manufacturers do not provide ongoing
maintenance, among other problems.
But not Sistema Biobolsa. As a lender, the company
has in interest in the plants’ long-term production of
methane. Of course, the operators profit from this as
well. “The farm recoups the investment quickly”, explains
Alex Eaton. And in this way, they can also pay the
loan back. Rancho Sinai would have to pay almost 290
euros per year and hectare just for industrial fertilizer.
This is a significant item because the farm grows the
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