Sustainable Campus: Reducing Environmental and Financial Burdens by Using Pruned Branches for On-Campus Energy

Sota Makino,Issei Sato,Akika Itoh,Takeshi Onishi,Chihiro Kayo,Tomohumi Huzita

doi:10.3390/su13137480

Sota Makino, Issei Sato + Show 4 more

Open Access

https://doi.org/10.3390/su13137480

Copy DOI

Abstract

Sustainability activities on university campuses are an important part of building a sustainable society. As a part of this effort, the present study quantitatively evaluated the reduction in greenhouse gas (GHG) emissions and disposal costs upon use of pruned branches for on-campus energy use in a Japanese university. The pruned branches are currently used off campus as fuel for biomass power generation, whereas the proposed systems include their on-campus use for heating through wood-chip heaters in a greenhouse or through wood stoves in buildings. The GHG balance was evaluated using a life-cycle assessment, and the cumulative costs over a 20 y period were estimated. Using pruned branches for on-campus heating was 70–180% more effective in reducing GHG emissions than the current off-campus power generation system. Using branches for heating eliminated the emissions produced by the transportation of pruned branches off campus and had higher thermal efficiency than power generation, which was conducive to the replacement of larger quantities of fossil fuel. In addition, the payback period of the proposed systems was estimated at 2 and 4 y for wood stove and wood-chip heater systems, respectively. For the 20 y period, the cumulative costs can be reduced by approximately 20%.

Highlights

Policies to create a sustainable society are urgently needed to mitigate climate change.In this context, universities can contribute to sustainability through research, education, social collaboration, and campus development [1]
The results of this study show that the use of pruned branches for heating in wood-chip heaters or wood stoves would reduce the greenhouse gas (GHG) emissions of the campus by 70–180% compared with the current off-campus power generation system
To evaluate the fossil fuel-derived GHG emissions and the reductions upon their substitution, we considered the distance the pruned branches and wood chips were transported, the amount of fuels used and replaced, and other factors obtained from the relevant university departments, pruners, waste disposal companies, and heating equipment manufacturers through interviews and collected numerical data (Table 1)

Summary

Introduction

Policies to create a sustainable society are urgently needed to mitigate climate change. In this context, universities can contribute to sustainability through research, education, social collaboration, and campus development [1]. Sustainable campus activities are often developed in universities to help reduce greenhouse gas (GHG) emissions and other environmental burdens, and contribute to a sustainable society [2,3]. To promote the use of renewable energy, the pruned branches produced in the green areas of campuses [10,11,12] can be potentially used as renewable woody biomass

Objectives

Methods

Discussion

Conclusion