WE PRESENT the concept of carbon capture with sugarcane technology
(CCST), whereby the ‘great grasses’ sequester atmospheric carbon
dioxide into a stable form of carbon while simultaneously converting
solar energy into transport fuel and creating valuable by-products. The
technology of growing and processing these grasses is well established
and could make a significant reduction to Australia’s carbon emissions
while earning valuable carbon credits. We have selected the great grasses:
‘energetic sugarcane’, sweet sorghum and nalgrass (Arundo donax)
because: (i) they each produce a sugar juice that is directly fermentable
into fuel ethanol, (ii) the bagasses from these grasses are an excellent
source of paper pulp, (iii) by-product lignin can be placed safely in the
ground as one of the most stable modes of carbon storage and (iv) paper
pulp made from bagasse displaces the more energy-intensive process
using wood chips. We refer to the overall scheme as the ‘Ethanol-Pulp-
Fertiliser Process’ (EPFP). The great grasses create useful biomass faster
than any other form of terrestrial plant. The three we have selected can be
grown, harvested and processed using established technologies for
sugarcane. Sweet sorghum and nalgrass can be grown in the sugarcane
slack season to permit year-round processing. The latter are also less
dependent on soil quality and moisture supply than high-sucrose
sugarcane thus reducing growing costs. A preferred area for plantations is
the three ‘drainage divisions’ of Northern Australia which receive 60% of
Australia's rainfall on only 25% of the land area as well as abundant
sunshine. As a scoping exercise we estimate that it would take about
53,100 square km equal to 3.2% of the division’s area to replace the
entirety of Australia's motor fuel consumption. The lignin by-product
would equal approximately equal to one quarter the amount of coal burnt
in Australian power stations. This area represents 8.3 times the land
current under sugarcane in all of Australia. Clearly replacement of ‘the entirety’ of the scheme, would take significant time to achieve.
Introduction of the technology on this scale would be staged, and initially
the grasses might be used to produce fuel ethanol and bagasse used for
power generation only. With time and development fully integrated EPFP
could be realised. Individual cane producers may wish to grasp the
initiative right now on a more limited scale.