Title:
Biomethane and Bioethanol from Energy Crops in Ireland: A Life-cycle Energy Balance
Author(s):
Deasy, E., Power, N.M.
Document(s):
Paper
Abstract:
The motivation for this research stems from the potential of biofuels to assist Ireland in meeting obligations outlined in the ‘Renewable Energy Source Directive’ (2009/28/EC). Under the ‘Renewable Energy Source Directive’ Ireland must increase renewable energy use by over five fold; it is required that a minimum of 10% of all transport fuel consumed in 2020 must be of renewable origin and that feedstocks used to achieve these targets must save a minimum of 60% of greenhouse gas emissions by 2018. This makes research into the energy balance of indigenous crops for biomethane and bioethanol production of significant relevance. Biofuels can help Ireland reduce its over reliance on imported fossil fuels, thus reducing economic reliance on countries from war torn regions of the world, encourage indigenous energy creation and provide indigenous jobs. The purpose of this work is to investigate and establish the energy consumed and created in the production of biomethane and bioethanol in Ireland; allowing for calculation of the true net energy. The two energy crops investigated are wheat and grass silage (assuming a three cut silage system). Both grass silage and wheat have long been grown, cultivated and harvested effectively in Ireland, therefore the knowledge and expertise for optimal crop production are already present. Grass accounts for 91% of the crop land area in Ireland with typical yields of 60t-FM/ha while wheat is consider as one of Irelands highest yielding cereals at 7.5 t-FM/ha. This analysis shall be broken into three distinct stages, the energy consumption stage (crop production and biofuel processing), the energy creation stage (biofuel processing – biomethane and bioethanol) and the energy balance stage. Each of these stages takes into consideration both the direct and indirect energy sinks in the effective production of each biofuel. The results show that biomethane from grass silage illustrates superior performance in relation to gross energy and net energy than biomethane and bioethanol from wheat. Biomethane from grass silage demonstrates low energy consumption rates (40.8GJ/ha), high net-energy levels (196.9GJ/ha) and low land consumption levels (4,207.9ha/PJ-gross energy). Wheat displayed a lower net energy return per hectare of crop; 41.4GJ/ha and 10.7GJ/ha for wheat biomethane and wheat bioethanol respectively.
Keywords:
bioethanol, energy balance, energy crops, biofuels, biomethane
Topic:
Biomass Policies, Markets and Sustainability
Subtopic:
Sustainability assessment and criteria
Event:
19th European Biomass Conference and Exhibition
Session:
VP5.2.38
Pages:
2657 - 2666
ISBN-13:
978-88-89407-55-4
ISBN-10:
88-89407-55-7
Paper DOI:
10.5071/19thEUBCE2011-VP5.2.38
Price:
FREE
