Carbon stock estimates for forests in the Castilla y León region, Spain. A GIS based method for evaluating spatial distribution of residual biomass for bio-energy

Analysis of aboveground biomass and carbon stocks (as equivalent CO₂) was performed in the Castilla y León region, Spain. Data from the second and third Spanish Forest Inventories (1996 and 2006) were used. Total aboveground biomass was calculated using allometric biomass equations and biomass expansion factors (BEF), the first method giving higher values. Forests of Castilla y León stored 77,051,308 Mg of biomass, with a mean of 8.18 Mg ha⁻¹, in 1996 and 135,531,737 Mg of biomass, with a mean of 14.4 Mg ha⁻¹, in 2006. The total equivalent CO₂ in this region’s forests increased 9,608,824 Mg year⁻¹ between 1996 and 2006. In relation to the Kyoto Protocol, the Castilla y León forests have sequestered 3 million tons of CO₂ per year, which represents 6.4% of the total regional emission of CO₂. A Geographic Information System (GIS) based method was also used to assess the geographic distribution of residual forest biomass for bio-energy in the region. The forest statistics data on area of each species were used. The fraction of vegetation cover, land slope and protected areas were also considered. The residual forest biomass in Castilla y León was 1,464,991 Mg year⁻¹, or 1.90% of the total aboveground biomass in 1996. The residual forest biomass was concentrated in specific zones of the Castilla y León region, suitable for the location of industries that utilize biomass as energy source. The energy potential of the residual forest biomass in the Castilla y León region is 7350 million MJ per year.     

Factors affecting nonindustrial private forest landowners' willingness to supply woody biomass for bioenergy

Bioenergy is a renewable form of potential alternative to traditional fossil fuels that has come to the forefront as a result of recent concerns over high price of fuels, national security, and climate change. Nonindustrial private forest (NIPF) landowners form the dominant forest ownership group in the southern United States. These forests often tend to have large quantities of small diameter trees. Use of logging residues and non-marketable small diameter trees for bioenergy production can create economic opportunities for NIPF landowners. The results demonstrated that landowners’ willingness to harvest woody biomass was influenced by their ownership objectives, size of the forest, structure and composition of tree species, and demographic characteristics. The model found that relatively younger landowners who owned large acres of forestland with pine plantations or mix forests had the potential to become a preferable choice for contractors, extension foresters and bioenergy industries as they were more likely to supply woody biomass for bioenergy. Findings of this study will be useful to bioenergy industries, extension foresters, nonindustrial private forest landowners and policy makers.     

The Role of Biomass in Greenhouse Gas Mitigation

Abstract

Biomass can play a dual role in greenhouse gas mitigation related to the objectives of the UNFCCC, i.e., as an energy source to substitute for fossil fuels and as a carbon store. However, compared to the maintenance and enhancement of carbon sinks and reservoirs, it appears that the use of biomass has so far received less attention as a means of mitigating climate change. Modern biomass options offer significant, cost-effective and perpetual opportunities toward meeting emission reduction targets while providing additional ancillary benefits. Moreover, via the sustainable use of the accumulated carbon, biomass has the potential for resolving some of the critical issues surrounding long-term maintenance of biotic carbon stocks. In the case of Turkey, energy consumption and environmental pollution are increasing rapidly due to its economic growth. As for the energy consumption, in parallel to the demand for heat and electricity, greenhouse gas emissions (GHGs) from energy use increase accordingly. In this regard, biomass and other renewables are becoming an attractive solution to the GHG mitigation for Turkey and other countries throughout the world. Finally, wood products can act as substitutes for more energy-intensive products, can constitute carbon sinks, and can be used as biofuels at the end of their lifetime.     

Nutrient fertilizer requirements for sustainable biomass supply to meet U.S. bioenergy goal

The U.S. Biomass Roadmap set forth a goal that, by the year 2030, biomass will supply energy approximately equivalent to 30% of current petroleum consumption. Here we report on the amount of nutrient fertilizers required to meet the proposed 1-billion tons of sustainable bioenergy biomass production annually. To meet this goal, U.S. agriculture (assuming a scenario with high yield increase and land use change) will have net removals of 40.3, 12.7, and 36.2 Tg (million tons) of N, P₂O₅, and K₂O, respectively. The 1-billion tons of bioenergy biomass production alone will remove 16.9, 5.2, and 18.2 Tg of N, P₂O_5, and K₂O, respectively, from U.S. agricultural land. Considering the efficiencies of fertilizers in soils and the contribution of biomass residuals in fields, the overall bioenergy-focused agriculture would require 58.2, 27.3, and 31.7 Tg of N, P₂O_5, and K₂O fertilizers, respectively; this corresponds to an overall nutrient fertilizer application increase by a factor of 5.5 over the base line (1997). This study indicates an increased need for domestic and/or international production facilities for fertilizers if the goal of the Biomass Roadmap is to be attained.     

Sustainable Biomass Production

This study aims to estimate, identify and evaluate the biomass production options, estimate the sustainable biomass production for energy, and estimate the energy potential of biomass production in Turkey. Within the framework of sustainable development, Turkey today faces the challenge of balancing economic growth with environmental progress. Sustainable biomass production potential mainly depends on the productivity and surplus land available for biomass production. Based on the surplus land available for plantation, the plantation options and biomass productivity, the sustainable biomass potential for energy is estimated. Among the biomass energy sources, fuelwood seems to be one of the most interesting because its share of the total energy production of Turkey is high at 21%. The total biomass energy potential of Turkey is about 32 Mtoe. The amount of usable biomass potential of Turkey is approximately 17 Mtoe. The electrical production from usable biomass has a net impact of $4.4 billion in personal and corporate income and represented more than 160,000 jobs.     

The Potential of Cassava Biomass as a Feedstock for Sustainable Biogas Production in South Africa

Cassava is currently being investigated for biogas production in South Africa as it offers multiple benefits such as high yields of starch and total dry matter. The chemical constituents of the cassava biomass were determined using standard methods. Using a locally fabricated laboratory batch fermenter, anaerobic digestion was carried out in a 25 L capacity digester maintained at 36 ± 0.5 ℃. Pre-treatment of the cassava biomass with spoilage fungi, Aspergillus niger and PeniciUium species yielded large amounts of fermentable sugars for digestion. Cassava slurry was made and mixed with zebra droppings （2：1 v/v） and loaded into the digester of 20 L working volume. Analysis results showed an increase in most nutrients after pretreatment except for starch which decreased from 76% to 60% as a result of its hydrolysis to fermentable sugars by the spoilage fungi. Theoretical biogas yields were between 0.71 nm3 and 0.75 nm^3 per kg VS （volatile solids） destroyed while the total biogas yields of between 250 nm^3 and 300 nm^3 per kg VS fed into the digester was obtained after 20 days residence time. Cassava is not yet a staple food in some BRICs countries like South Africa and the peels and other by-products of its processing are equally suitable for energy production. The use of cassava will be an alternative feedstock strategy for several rural biogas projects running with cow dungs inside South Africa. In addition, opportunities exist for decentralized, cheaper and socially advantageous bioenergy production from cassava considering that fuel and electricity needs are not satisfied in many rural areas. Finally, the incorporation of cassava anaerobic digestion facility at different scales will deliver additional benefits like the incorporation of nutrients and residual carbon into the land as fertilizer.     

Stakeholders’ perceptions on forest biomass-based bioenergy development in the southern US

This study analyzes perceptions of four stakeholder groups (non-governmental organizations [NGOs], government, industry, and academia) regarding forest biomass-based bioenergy development in the southern US (United States) by combining SWOT (Strength, Weakness, Opportunities, and Threats) framework with AHP (Analytical Hierarchy Process). Results suggest that NGO representatives perceived rural development as an important opportunity. Government stakeholder group noted that less or no competition with food production and promotes energy security were major strength factors. Conversion technologies are still under trial was identified as a major weakness by industry representatives. Representatives of academia felt that the competition from other renewable energy sources could be a major threat. Overall, all stakeholder groups were in favor of forest biomass-based bioenergy development in the southern US.