scholarly journals Feasibility of a Harvesting System for Small-Diameter Trees as Unutilized Forest Biomass in Japan

Forests ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 74
Author(s):  
Takuyuki Yoshioka ◽  
Tomoki Tomioka ◽  
Toshio Nitami
Keyword(s):  
Sensitivity Analysis ◽  
Renewable Energy ◽  
Forest Biomass ◽  
Small Diameter ◽  
Simplified Model ◽  
Planted Forests ◽  
Forest Road ◽  
Upper Limits ◽  
Small Diameter Trees ◽  
Future Policy

In order to secure a supply of forest biomass, as well as promote further utilization following the completion of the Feed-in-Tariff Scheme for Renewable Energy (FIT), small-diameter trees such as cleanings from young planted forests and broad-leaved trees from coppice forests are prospective resources in Japan. The goal of this study was to discuss effective methods for harvesting the small-diameter trees that are unutilized forest biomass in Japan. This study assumed a simplified model forest and conducted experiments and time studies of the harvesting of small-diameter trees with a truck-mounted multi-tree felling head. As a result, the machine used in the experiment could fell a maximum of six trees inward in a row from a forest road. However, the harvesting cost (felling, accumulating and chipping) was cheapest when the machine felled five trees inward in a row. Lengthening the maximum reach of a felling head to fell trees deeper inward in a row appeared effective in increasing the number of harvested trees. From the perspective of minimizing the harvesting cost, however, there were upper limits to the number of trees felled inward as well as to the maximum reach of a felling head. The results of a sensitivity analysis suggested the following machine improvements could be considered in future policy: increasing the moving velocity of a felling head and the maximum number of trees that can be held at a time are effective if it is possible to lengthen the maximum reach of a felling head. Meanwhile, shortening the machine’s moving time among operation points is also effective if the maximum reach of a felling head cannot be lengthened.

scholarly journals Basic Examination of the Harvesting of Small-Diameter Trees as Unutilized Forest Biomass in Japan

2020 ◽  
Vol 3 (1) ◽  
pp. 7
Author(s):  
Takuyuki Yoshioka ◽  
Tomoki Tomioka ◽  
Toshio Nitami
Keyword(s):  
Renewable Energy ◽  
Forest Biomass ◽  
Small Diameter ◽  
Simplified Model ◽  
Planted Forests ◽  
Supply Source ◽  
Forest Road ◽  
Small Diameter Trees ◽  
Basic Examination ◽  
Feed In Tariff

In order to secure the supply source as well as promote the further utilization of forest biomass following the completion of the Feed-in Tariff Scheme for Renewable Energy (FIT), small-diameter trees, including samples from not only young planted forests but also broad-leaved trees from coppice forests, can be expected to be a prospective solution in Japan. With the aim of discussing the most effective method of harvesting such small-diameter trees as unutilized forest biomass appropriate for Japan, a simplified model forest was assumed in this study, while the harvesting of small-diameter trees was investigated with a truck-mounted multi-tree felling head and time-studied. As a result, the machine used in the experiment could fell a maximum of six trees in a row from a forest road, but the harvesting (felling, accumulating, and chipping) cost was the lowest when the machine felled five trees in a row.

scholarly journals Technology Pathways and Economic Analysis for Transforming High Temperature to Low Temperature District Heating Systems

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3218
Author(s):  
Pedro Durán ◽  
Herena Torio ◽  
Patrik Schönfeldt ◽  
Peter Klement ◽  
Benedikt Hanke ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Renewable Energy ◽  
High Temperature ◽  
Low Temperature ◽  
Economic Analysis ◽  
District Heating ◽  
Heating System ◽  
District Heating System ◽  
Heating Systems ◽  
District Heating Systems

There are 1454 district heating systems in Germany. Most of them are fossil based and with high temperature levels, which is neither efficient nor sustainable and needs to be changed for reaching the 2050 climate goals. In this paper, we present a case study for transforming a high to low temperature district heating system which is more suitable for renewable energy supply. With the Carnot Toolbox, a dynamic model of a potential district heating system is simulated and then transformed to a low temperature supply. A sensitivity analysis is carried out to see the system performance in case space constrains restrict the transformation. Finally, an economic comparison is performed. Results show that it is technically possible to perform the transformation until a very low temperature system. The use of decentralized renewable sources, decentralized heat storage tanks and the placement of a heat pump on each building are the key points to achieve the transformation. Regarding the sensitivity analysis, the transformation is worth doing until the seasonal storage and solar collector field sizes are reduced to 60% and 80% of their values in the reference case, respectively. The economic analysis shows, however, that it is hard for highly efficient low temperature renewable based heat networks to compete with district heating systems based on a centralized fossile CHP solution. Thus, though the presented transformation is technically possible, there is a strong need to change existing economic schemes and policies for fostering a stronger promotion of renewable energy policies in the heat sector.

Evaluation of moisture reduction in small diameter trees after crushing

1991 ◽  
Vol 37 (1) ◽  
pp. 53-60 ◽  
Author(s):  
Donald L. Sirois ◽  
Cynthia L. Rawlins ◽  
Bryce J. Stokes
Keyword(s):  
Small Diameter ◽  
Small Diameter Trees

scholarly journals Tree height integrated into pantropical forest biomass estimates

2012 ◽  
Vol 9 (8) ◽  
pp. 3381-3403 ◽  
Author(s):  
T. R. Feldpausch ◽  
J. Lloyd ◽  
S. L. Lewis ◽  
R. J. W. Brienen ◽  
M. Gloor ◽  
...  
Keyword(s):  
East Africa ◽  
Carbon Storage ◽  
Stand Structure ◽  
Forest Biomass ◽  
Small Diameter ◽  
Tree Height ◽  
Total Biomass ◽  
Guiana Shield ◽  
Tree Biomass ◽  
Continental Scale

Abstract. Aboveground tropical tree biomass and carbon storage estimates commonly ignore tree height (H). We estimate the effect of incorporating H on tropics-wide forest biomass estimates in 327 plots across four continents using 42 656 H and diameter measurements and harvested trees from 20 sites to answer the following questions: 1. What is the best H-model form and geographic unit to include in biomass models to minimise site-level uncertainty in estimates of destructive biomass? 2. To what extent does including H estimates derived in (1) reduce uncertainty in biomass estimates across all 327 plots? 3. What effect does accounting for H have on plot- and continental-scale forest biomass estimates? The mean relative error in biomass estimates of destructively harvested trees when including H (mean 0.06), was half that when excluding H (mean 0.13). Power- and Weibull-H models provided the greatest reduction in uncertainty, with regional Weibull-H models preferred because they reduce uncertainty in smaller-diameter classes (≤40 cm D) that store about one-third of biomass per hectare in most forests. Propagating the relationships from destructively harvested tree biomass to each of the 327 plots from across the tropics shows that including H reduces errors from 41.8 Mg ha−1 (range 6.6 to 112.4) to 8.0 Mg ha−1 (−2.5 to 23.0). For all plots, aboveground live biomass was −52.2 Mg ha−1 (−82.0 to −20.3 bootstrapped 95% CI), or 13%, lower when including H estimates, with the greatest relative reductions in estimated biomass in forests of the Brazilian Shield, east Africa, and Australia, and relatively little change in the Guiana Shield, central Africa and southeast Asia. Appreciably different stand structure was observed among regions across the tropical continents, with some storing significantly more biomass in small diameter stems, which affects selection of the best height models to reduce uncertainty and biomass reductions due to H. After accounting for variation in H, total biomass per hectare is greatest in Australia, the Guiana Shield, Asia, central and east Africa, and lowest in east-central Amazonia, W. Africa, W. Amazonia, and the Brazilian Shield (descending order). Thus, if tropical forests span 1668 million km2 and store 285 Pg C (estimate including H), then applying our regional relationships implies that carbon storage is overestimated by 35 Pg C (31–39 bootstrapped 95% CI) if H is ignored, assuming that the sampled plots are an unbiased statistical representation of all tropical forest in terms of biomass and height factors. Our results show that tree H is an important allometric factor that needs to be included in future forest biomass estimates to reduce error in estimates of tropical carbon stocks and emissions due to deforestation.

scholarly journals A Simplified Model for Predicting Friction Factors of Laminar Blood Flow in Small-Caliber Vessels

Fluids ◽  
2018 ◽  
Vol 3 (4) ◽  
pp. 75 ◽  
Author(s):  
Aikaterini Mouza ◽  
Olga Skordia ◽  
Ioannis Tzouganatos ◽  
Spiros Paras
Keyword(s):  
Blood Flow ◽  
Pressure Drop ◽  
Friction Factor ◽  
Small Diameter ◽  
Numerical Data ◽  
Blood Flow Rate ◽  
Vessel Diameter ◽  
Simplified Model ◽  
Glycerol Solution ◽  
Fanning Friction Factor

The aim of this study was to provide scientists with a straightforward correlation that can be applied to the prediction of the Fanning friction factor and consequently the pressure drop that arises during blood flow in small-caliber vessels. Due to the small diameter of the conduit, the Reynolds numbers are low and thus the flow is laminar. This study has been conducted using Computational Fluid Dynamics (CFD) simulations validated with relevant experimental data, acquired using an appropriate experimental setup. The experiments relate to the pressure drop measurement during the flow of a blood analogue that follows the Casson model, i.e., an aqueous Glycerol solution that contains a small amount of Xanthan gum and exhibits similar behavior to blood, in a smooth, stainless steel microtube (L = 50 mm and D = 400 μm). The interpretation of the resulting numerical data led to the proposal of a simplified model that incorporates the effect of the blood flow rate, the hematocrit value (35–55%) and the vessel diameter (300–1800 μm) and predicts, with better than ±10% accuracy, the Fanning friction factor and consequently the pressure drop during laminar blood flow in healthy small-caliber vessels.

scholarly journals Eucalyptus sp. WOODCHIP POTENTIAL FOR INDUSTRIAL THERMAL ENERGY PRODUCTION1

2017 ◽  
Vol 41 (6) ◽  
Author(s):  
Marcos Antonio da Silva Miranda ◽  
Gabriel Browne de Deus Ribeiro ◽  
Sebastião Renato Valverde ◽  
Crismeire Isbaex
Keyword(s):  
Energy Source ◽  
Thermal Energy ◽  
Fossil Fuels ◽  
Forest Biomass ◽  
Dairy Industry ◽  
Industrial Sector ◽  
Cost Ratio ◽  
Planted Forests ◽  
Industrial Use ◽  
The Cost

ABSTRACT The main objective of this work was to identify and analyze the potential of forest biomass of Eucalyptus sp. such as thermal energy source for industrial use in place of fossil fuels. Two cases were analyzed: the first one estimated the total demand for forest biomass to replace the main fossil fuels in Brazilian industrial sector, with scenarios of 100, 75 and 50% replacement; in the second, it was calculated the cost of each fuel for producing ton of industrial steam (thermal energy) for a dairy industry, in order to verify the competitiveness of forest biomass compared to fossil fuels. The results showed that the areas demanded to replace 100, 75 and 50% of the analyzed fossil fuels were, respectively, 2.9, 2.2 and 1.5 million planted forests hectares, and the steam ton cost ratio using the woodchips was at least 34% lower than with other fuels, which corroborates the substitution potential in this sector.

Renewable Energy for a Low-Carbon Future: Policy Perspectives

2020 ◽  
pp. 267-284
Author(s):  
Shiv Prasad ◽  
V. Venkatramanan ◽  
Anoop Singh
Keyword(s):  
Renewable Energy ◽  
Low Carbon ◽  
Future Policy

scholarly journals Chipping Whole Trees for Fuel Chips: A Production Study

2007 ◽  
Vol 31 (4) ◽  
pp. 176-180 ◽  
Author(s):  
Dana Mitchell ◽  
Tom Gallagher
Keyword(s):  
Loblolly Pine ◽  
Longleaf Pine ◽  
Small Diameter ◽  
Wage Rates ◽  
Time And Motion ◽  
Motion Study ◽  
Average Production ◽  
Production Study ◽  
Small Diameter Trees ◽  
The Cost

Abstract A time and motion study was conducted to determine the productivity and cost of an in-woods chipping operation when processing whole small-diameter trees for biomass. The study removed biomass from two overstocked stands and compared the cost of this treatment to existing alternatives. The treatment stands consisted of a 30-year-old longleaf pine stand and a 37-year-old loblolly pine stand. In the longleaf pine stand, 71% of the trees removed were less than 5 in. dbh. In the loblolly pine stand, approximately 81% of the stems removed were less than 5 in. dbh. The harvesting system consisted of conventional ground-based harvesting equipment and a three-knife chipper that processed the biomass into fuel chips. The average production time to fill a chip van was 24.61 minutes. The chip moisture content averaged 94.11% (dry basis). Using machine rates and federal labor wage rates, the in-woods cost of producing fuel chips was $9.18/green ton (gt). The cost of the biomass chipping operation ($15.18/gt), including transportation, compared favorably to existing alternative treatments of cut-and-pile or mulching.

Optimal planning and sensitivity analysis of green microgrid using various types of storage systems

2020 ◽  
pp. 0309524X2094147
Author(s):  
Sumit Sharma ◽  
Yog Raj Sood
Keyword(s):  
Sensitivity Analysis ◽  
Renewable Energy ◽  
Storage Systems ◽  
Operating Cost ◽  
Indian Policy ◽  
Policy Interventions ◽  
Cost Of Energy ◽  
Pumped Storage ◽  
Test Scenarios ◽  
Storage Units

In this article, a green microgrid is suggested which utilizes renewable energy units such as wind, solar, hydro, and biomass in conjunction with energy storage systems like batteries and the pumped storage. Different test scenarios are investigated to optimally use the power generated from the combined usage of the renewable energy units and the storage units. To judge the performance, a comparative feasibility analysis of the proposed approach is carried out to demonstrate the potential findings based on the total net present cost, levelized cost of energy, operating cost, and initial capital cost. In addition, the proposed solution may be subject to various changes in systems configuration with regard to the wind speed, solar radiation, streamflow, and the electric load; therefore, sensitivity analysis is also presented. Moreover, Indian policy interventions are considered to demonstrate the effectiveness of the proposed approach for a reduction in the overall revenue of the system.

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