Biomass sequestration

Biomass sequestration, which has been embraced by coal companies as the least expensive way to start carbon management, relies on capture from air. Cofiring with biomass followed by sequestration also would lead to a net C02 reduction in the atmosphere (Keith, 2001). On a per ton basis, this option is quite cost effective, but the amount of land area that would be required is extremely large to be practical. Consequently, it is worthwhile to consider other options. Currently, studies that consider capture of C02 directly from the air by chemical means are under way. These processes will require good chemical sorbents that do not pose any environmental concerns in their own right and can be regenerated cost effectively. 

By 2050 total energy demand may have increased by a factor of 2 or 3 from today s. So, in order to meet such a condition, carbon-fiee energy supply would have to have grown by a factor of nearly 15. In that time-span the only sources of carbon free energy are renewables, such as solar biomass and wind, sequestration (exclusion of C02 from the atmosphere) and nuclear fission. There is considerable debate, but no conclusion, how fat and how fast renewables might grow, but clearly, if economic and acceptable, here is a major potential opening for nuclear power. 

Keywords biomass, carbon sequestration, edge effect, fragmentation, native forest... 

The coprocessing of coal in gasification processes together with biomass (C02 separation and sequestration, sulfur species removal, and trace element emissions)... 

Hansen EA (1993) Soil carbon sequestration beneath hybrid poplar plantations in the north central United States. Biomass Bioenergy 6 431-436... 

If H2 is made from renewable fuels such as biomass, or nuclear energy, or fossil fuel resources with C02 capture and sequestration, it would be possible to generate emission-free electricity in the future. 

Today s rapidly increasing activities on hydrogen focus mostly on vehicle applications and less on stationary applications. For fuel cells, stationary applications are also relevant, but natural gas will be the dominant fuel here. The dominance of the transport sector is also reflected in the hydrogen roadmaps developed, among others, in the EU, the USA, Japan, or at an international level. Whereas in the beginning, onsite or decentralised production options based on fossil fuels or electricity are seen as the major option for hydrogen production, later on central production options will dominate the market. Here, several options could play a role, from coal, with carbon capture and sequestration, through natural gas and renewables (wind, biomass) to nuclear. A C02-free or lean vision can be identified in every roadmap. The cost... 

All coal and central natural-gas hydrogen plants are assumed to have carbon-capture and sequestration (CCS). Biomass hydrogen plants are assumed to be smaller (30-200 tonnes/day), compared with 50-400 tonnes/day for natural gas central SMRs, and 250-1200 tonnes/day for coal plants. We use a regional biomass supply curve (which specifies the amount of biomass available at a certain /tonne) (Walsh et al., 1999), to reflect biomass feedstock cost increases as demand grows. 

However, biomass plants appear earlier than coal and more biomass plants are built, because they are smaller and can become central supplies at smaller market penetration. It is important to note that the delivered cost of hydrogen from coal, biomass and natural gas central plants are typically quite close (within 0.5/kg). Thus, the choice of a feedstock may be determined by other factors, such as state policies favouring renewables and the availability of carbon-sequestration sites. 

Using hydrogen to produce electrical energy from fossil fuels in large centralised plants will contribute positively to achieving important reductions of C02 emissions, if this is combined with C02 capture and sequestration processes. Such plants will also help to increase the diversification of resources, since a variety of fossil feedstocks can be used, including resources such as coal and waste that otherwise cause major impacts on the environment, as well as biomass. 

Biomass, via its photosynthesis, has provided energy for life for the longest period of its existence. Industrial processes that take-in biomass can be integrated with the natural photosynthesis/respiration cycle of vegetation. If used in this manner, biomass is a renewable energy source and, by its utilization, overall much less C02 is added to the atmosphere compared with the fossil fuel counterpart processes. When combined with C02 sequestration, biomass based processes can actually lower the C02 concentration in the atmosphere [11],... 

The rate of growth of the trees slows as the forest reaches maturity and canopy closure occurs. In addition, the forest eventually establishes equilibrium with the environment, where the rate of carbon sequestration is exactly balanced by the loss of carbon dioxide to the atmosphere due to decay of dead trees and other biomass. 

Cannell, M.G.R. (2003). Carbon sequestration and biomass energy offset theoretical, potential and achievable capacities globally, in Europe and the UK. Biomass and Bioenergy, 24(2), 97-116. 

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