Open AccessConsequential life cycle assessment of miscanthus livestock bedding, diverting straw to bioelectricity generation
Author(s) -
Yesufu Jalil,
McCalmont Jon P.,
CliftonBrown John C.,
Williams Prysor,
Hyland John,
Gibbons James,
Styles David
Publication year - 2020
Publication title -
gcb bioenergy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.378
H-Index - 63
eISSN - 1757-1707
pISSN - 1757-1693
DOI - 10.1111/gcbb.12646
Subject(s) - miscanthus , life cycle assessment , environmental science , livestock , greenhouse gas , straw , fossil fuel , bedding , pasture , arable land , bioenergy , agronomy , biofuel , agroforestry , agriculture , waste management , production (economics) , biology , ecology , engineering , economics , macroeconomics , horticulture
Straw is an important livestock bedding material facing increasing demand for alternative uses in Europe and is often transported long distances from arable to livestock regions. Alternative bedding materials cultivated directly on livestock farms could potentially avoid this transport and competition for use. For the first time, we applied consequential life cycle assessment (LCA) to account for the direct and indirect implications of miscanthus bedding production on livestock farms, considering displacement of fodder or livestock, and substitution of fossil fuels with straw in electricity generation. We modelled the effect of substituting straw with ‘home‐grown’ miscanthus bedding across seven beef and sheep farms. The consequences of displacing grass forage (or animal) production with home‐grown miscanthus bedding cultivation were evaluated via three farmer decision scenarios: buy extra concentrate feed (D 1 ), utilize remaining pasture areas more efficiently (D 2 ) and buy grass silage (D 3 ). Electricity generated from displaced straw (bedding) substituted either natural gas or coal electricity. Sensitivity analyses were undertaken using 34 scenario permutations to represent combinations of feed and electricity substitution, miscanthus fertilization rates and yields, and the quality of displaced pasture. Consequential LCA indicates that miscanthus bedding production could be environmentally beneficial, under scenarios involving D 2 and D 3 . However, greenhouse gas emissions and wider environmental burdens may be increased under D 1 scenarios, owing to the environmental cost of additional concentrate feed production, and possible indirect land use change, outweighing the benefits from: (a) fossil electricity substitution with straw bioelectricity; (b) reduced animal emissions via improved digestibility of concentrate feed; (c) avoided straw transport. The ratio of the yield of miscanthus to replaced grass was found to be a critical determinant of D 1 environmental outcomes. We conclude that if grass forage production can be better managed, the use of miscanthus as a bedding material on livestock farms provides environmental benefits via diversion of straw to bioenergy use.