Forest-based Biofuel Research Articles

Effects of Site Preparation for Pine Forest/Switchgrass Intercropping on Water Quality.

A study was initiated to investigate the sustainability effects of intercropping switchgrass ( L.) in a loblolly pine ( L.) plantation. This forest-based biofuel system could possibly provide biomass from the perennial energy grass while maintaining the economics and environmental benefits of a forest managed for sawtimber. Operations necessary for successful switchgrass establishment and growth, such as site preparation, planting, fertilizing, mowing and baling, may affect hydrology and nutrient runoff. The objectives of this study were (i) to characterize the temporal effects of management on nutrient concentrations and loadings and (ii) to use pretreatment data to predict those treatment effects. The study watersheds (∼25 ha each) in the North Carolina Atlantic Coastal Plain were a pine/switchgrass intercropped site (D1), a midrotation thinned pine site with natural understory (D2), and a switchgrass-only site (D3). Rainfall, drainage, water table elevation, nitrogen (total Kjedahl N, NH-N, and NO-N), and phosphate were monitored for the 2007-2008 pretreatment and the 2009-2012 treatment periods. From 2010 to 2011 in site D1, the average NO-N concentration effects decreased from 0.18 to -0.09 mg L, and loads effects decreased from 0.86 to 0.49 kg ha. During the same period in site D3, the average NO-N concentration effects increased from 0.03 to 0.09 mg L, and loads effects increased from -0.26 to 1.24 kg ha. This study shows the importance of considering water quality effects associated with intensive management operations required for switchgrass establishment or other novel forest-based biofuel systems.

Rodent population and community responses to forest-based biofuel production

Intensively managed forests in the southeastern United States are a potential source of cellulosic bioenergy and, as conversion technologies improve and demand increases, a greater land area may be required to produce biofuel feedstocks. However, responses of wildlife to forest-based biofuel production are largely unknown. We examined the 4-year response of rodent populations and assemblages to a range of biofuel production regimes, including harvesting residual woody debris and intercropping switchgrass (Panicum virgatum), in an intensively managed loblolly pine (Pinus taeda) forest in eastern North Carolina, USA. We investigated abundance, demography, and community response of rodents in a randomized and replicated field experiment using mark-recapture techniques during 2009–2012. Whereas removal of downed woody biomass did not affect abundance, diversity, or demography of rodents, we detected species-specific effects of incorporating switchgrass. After switchgrass was well established, invasive house mice (Mus musculus) were most abundant in plots with switchgrass. In contrast, white-footed mice (Peromyscus leucopus) were commonly captured in plots without switchgrass and other rodents were not affected by biofuel treatments. Across the study, natural succession exerted greater effects on rodent species and the rodent community than biofuel production regimes. As remaining logs and stumps decay and become limiting, downed wood may become more important to rodents. Our results indicate that intercropping switchgrass and harvesting residual woody material had limited effects on rodents in the Coastal Plain of North Carolina, USA within 4 years of stand establishment.

Assessing external factors on substitution of fossil fuel by biofuels: model perspective from the Nordic region

The aim of this study is to develop a theoretical model by which to demonstrate how taxes and subsidies work as external factors to substitute fossil fuel by a forest-based biofuel. For biofuels, this study predominantly considers solid-form biomass that generates electricity; for fossil fuels, it considers coal. The model results explicated with three states by using various numeric values taken from the literature. Three states are as follows: a situation without a tax and subsidy, a situation with a biofuel subsidy, and a situation with a biofuel subsidy and a fossil fuel tax. The results of the first state exemplify current fuel market situation; those of the second indicate that the aggregate demand for biofuel has shifted upwards by around 15 % and that substitution has increased by around 18 % due to biofuel subsidies being offered. Under the third state, aggregate biofuel demand has shifted upwards by around 19 %, reduced the demand for fossil fuels by around 13 %, and increased substitution by around 31 %. This state relates to a greater sense of social welfare than other two states. It is conceivable that the joint application of taxes and subsidies will succour biofuel to supplant fossil fuel in the near future.

A cost model for forest-based biofuel production and its application to optimal facility size determination

With continued concerns regarding the use of fossil fuels and energy security, there is increasing interest in biofuels. However, owing to worries over the use of agricultural feedstocks for biofuel, forest biomass as a feedstock has been investigated for some time and appears to be a promising alternative. Current corn-based ethanol facilities range in size from a few million to over 380million liters (100million gallons) per year with associated construction costs near $117million for the latter sized capacity. On the other hand, the economics for forest biomass to biofuel facilities are different and there appears to be a lack of understanding about the cost optimal size for the processing facility and the associated investment. With this in mind, a mathematical model is developed to describe the total annual costs of a forest biomass to biofuel facility using the Upper Peninsula of Michigan as the case study area. The model includes terms associated with forest resource harvesting and collection, transportation, storage, and facility construction and operation costs. The model is used to establish a relationship for the optimal size of a production facility, that is, the facility size that provides the minimum unit cost. The effect of various factors on the optimal facility size and the associated biofuel unit cost are examined, especially transportation cost rate and equivalent yield. The results indicate these two factors do impact optimal size and unit cost.

The water footprint of biofuel produced from forest wood residue via a mixed alcohol gasification process

Forest residue has been proposed as a feasible candidate for cellulosic biofuels. However, the number of studies assessing its water use remains limited. This work aims to analyze the impacts of forest-based biofuel on water resources and quality by using a water footprint approach. A method established here is tailored to the production system, which includes softwood, hardwood, and short-rotation woody crops. The method is then applied to selected areas in the southeastern region of the United States to quantify the county-level water footprint of the biofuel produced via a mixed alcohol gasification process, under several logistic systems, and at various refinery scales. The results indicate that the blue water sourced from surface or groundwater is minimal, at 2.4 liters per liter of biofuel (l/l). The regional-average green water (rainfall) footprint falls between 400 and 443 l/l. The biofuel pathway appears to have a low nitrogen grey water footprint averaging 25 l/l at the regional level, indicating minimal impacts on water quality. Feedstock mix plays a key role in determining the magnitude and the spatial distribution of the water footprint in these regions. Compared with other potential feedstock, forest wood residue shows promise with its low blue and grey water footprint.

The potential of forest-derived bioenergy to contribute to China's future energy and transportation fuel requirements

Increasing concerns of oil security, greenhouse gas emissions, and sustainability have encouraged nations to consider the contribution that agriculture/forestry for bioenergy (and biofuels in particular) could make as alternatives to current fossil-based energy and transportation fuels. Despite China's large population and geographical size, it has only relatively recently developed into a highly industrialized and energy-dependent economy. Coal is, and will remain, China's dominant energy source. However, over the last few years with China's growing middle class, increasing growth in production and sale of cars/trucks and a growing chemical based sector, oil and its derivatives are predicted to experience the fastest fossil fuel growth. China's ability to produce so-called “first-generation” or conventional biofuels from sugar, starch or vegetable oil based plants is very restricted because of “food vs. fuel” issues. Thus, biomass-based and forest-based biofuels, in particular, can form a medium-to-long-term solution that could contribute to China's national biofuels targets. Oilseed trees have been suggested as an initial forest-based biodiesel strategy with about 13 million ha of marginal land identified for possible plantation. It is also estimated that 17 million tonnes of cellulosic ethanol per annum could be derived from forest biomass that is currently available in China.

Fuel-Mix, Fuel Efficiency, and Transport Demand Affect Prospects for Biofuels in Northern Europe

Rising greenhouse gas (GHG) emissions in the road transport sector represents a difficult mitigation challenge due to a multitude of intricate factors, namely the dependency on liquid energy carriers and infrastructure lock-in. For this reason, low-carbon renewable energy carriers, particularly second generation biofuels, are often seen as a prominent candidate for realizing reduced emissions and lowered oil dependency over the medium- and long-term horizons. However, the overarching question is whether advanced biofuels can be an environmentally effective mitigation strategy in the face of increasing consumption and resource constraints. Here we develop both biofuel production and road transport consumption scenarios for northern Europe-a region with a vast surplus of forest bioenergy resources-to assess the potential role that forest-based biofuels may play over the medium- and long-term time horizons using an environmentally extended, multiregion input-output model. Through scenarios, we explore how evolving vehicle technologies and consumption patterns will affect the mitigation opportunities afforded by any future supply of forest biofuels. We find that in a scenario involving ambitious biofuel targets, the size of the GHG mitigation wedge attributed to the market supply of biofuels is severely reduced under business-as-usual growth in consumption in the road transport sector. Our results indicate that climate policies targeting the road transport sector which give high emphases to reducing demand (volume), accelerating the deployment of more fuel-efficient vehicles, and promoting altered consumption patterns (structure) can be significantly more effective than those with single emphasis on expanded biofuel supply.