Repurposing Grape Marc in marlborough: The Way Forward - from Assessment of Options to Next Steps
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Date
2020-06-03
DOI
Open Access Location
Journal Title
Journal ISSN
Volume Title
Publisher
Marlborough District Council
Rights
(c) The Authors
Abstract
Five options for repurposing grape marc in Marlborough have been investigated in the techno-enviro-economic analyses presented in two reports and at two fora . The two fora were attended by wine industry representatives. A number of the participants attending the second forum have agreed to establish a Working Group. A first meeting is planned, to which representatives of the major peak bodies and wine industry groups will be invited. The Working Group will determine the option or options to take to Stage II development.
This study was initiated by the Marlborough District Council and is funded in part by them and by the Waste Minimisation Fund. The motivation to consider alternatives for repurposing grape marc has a number of contributing factors; (i), the quantity of grape marc is large, estimated in 2019 at 46,000 tonnes from 305,467 tonnes of pressed grapes, which produce an estimated 218 million litres of wine; (ii), the vineyard area is expanding rapidly, from 25,135 ha (2017) to 27,808 ha (2020). (iii), earlier attempts to compost grape marc led to prosecution of some operators for poor environmental outcomes; (iv), direct land-spreading of raw grape marc has arisen as the preferred activity but is not without environmental risk; (v), both direct land-spreading and composting require land and necessitate take-back arrangements with winegrowers; and (vi), neither composting nor direct land-spreading offer the opportunity to value add.
All five options investigated here avoid that risk. They are:
• best-practice composting;
• drying to make dried grape marc for sale;
• combustion to generate steam to make electricity;
• gasification to produce electricity in gas engines and excess heat; and,
• pyrolysis to produce biochar/charcoal and excess heat.
Some calculations are also included for comparison with direct land-spreading of raw grape marc. A number of these options have viable commercialisation pathways that balance positive environmental outcomes with volume reduction of grape marc and profitability. They all require capital investment. This report summarises the options and presents the next steps towards commercialisation. The Working Group will further assess and refine these options.
Description
Keywords
biochar, compost, grape marc, thermal processing
Citation
Repurposing Grape Marc in marlborough: The Way Forward - from Assessment of Options to Next Steps, 2020, pp. 1 - 13 (13)