[Terrapreta] Comment to bioenergy with carbon storage (BECS)

[Christoph Steiner]

Comment to bioenergy with carbon storage (BECS)

Carbon-negative bioenergy to cut global warming could drive deforestation:
An interview on BECS with Biopact’s Laurens Rademakers
Mongabay.com (November 6, 2007)
http://news.mongabay.com/2007/1106-carbon-negative_becs.html

The article on mongabay.com deals about a proposed mechanism for
generating carbon-negative bioenergy. Bioenergy with carbon storage (BECS)
holds out the prospect of reducing CO2 from the atmosphere while producing
carbon-negative energy. The article provides an informative introduction
on how “carbon-negativity” is feasible and assumes
geosequestration (developed from the “clean coal” industry,
CO2 capture in depleted oil and gas fields, saline aquifers etc.) as the
sequestering tool. Laurens Rademakers delineates the risks such as
deforestation of tropical rainforests and leakage of geosequestration. In
addition these technologies require vast capital inputs and large scale
projects.
A substantive difference of bio-energy to fossil-energy allows Charcoal
Carbon Capture!
Geosequestration and carbon capture technologies are currently being
developed by the coal industry in order to produce the so-called
“clean coal”. Using this technology, the coal industry can at
best reduce its CO2 emissions, while using re-growing biomass would
establish a carbon sink. This substantive difference allows bio-energy
(energy from re-growing biomass) production systems to apply yet another
way to capture carbon – Charcoal Carbon Sequestration! Bio-energy
with charcoal carbon sequestration (BECCS) would only capture a maximum of
50% of the carbon stored in the biomass but offers the following
advantages:

1)Decentralized and small scale projects are feasible

2)Large capital investments are not necessary. The technologies range from
small cooking stoves to large bioenergy production units. No carbon
capture technology is necessary as charcoal is a byproduct of
gasification. As price for the incomplete gasification a proportion of the
energy (geosequestration demands energy too) is invested to capture carbon
in charcoal

3) Biochar (Charcoal used as soil amendment) increases soil fertility and
sustainability (important for continuous cropping for energy or food
crops)

4) No risk of harmful CO2 leakage as in systems like geosequestration.
Most scientists agree that the half life of charcoal is in the range of
centuries or millennia.

5) Only re-growing resources can establish a carbon sink. Tropical
Rainforest is not considered as re-growing resource in a BECCS scenario.
An access to the C trade market holds out the prospect to reduce
deforestation of primary forest, because using intact primary forest would
reduce the C credits. The estimated above-ground biomass of unlogged
forests is around 400 Mg ha 1, about half of which is C. This C is lost at
a high percentage if used for gasification and only < 50% is captured by
BECCS. The C trade could provide an incentive to cease further
deforestation; instead reforestation and recuperation of degraded land for
fuel and food crops would gain magnitude.