Determining the feasibility of harvesting invasive alien plant species for energy

Worship Mugido,Ben Cobbing,David Le Maitre,Selmé Joubert,James Jansen,Matthew Joubert,Andrew Knipe,James Blignaut,Marius Van Der Vyfer,John De Wet

doi:10.1590/sajs.2014/20130397

Abstract

Woody invasive alien plants (IAPs) are a threat to South Africa’s water resources, biodiversity and land productivity. The impacts of IAPs were the main reason for the South African government to embark on a natural resource management public works programme called Working for Water (WfW), which was aimed at controlling IAPs in a cost-effective yet labour-intensive way. At the same time, the high biomass of these species presents opportunities for synergies between the clearing of IAPs and the generation of biomass-based energy. The purpose of this study was to determine the cost of harvesting and extracting, chipping, and transporting the biomass, and also to determine the financial and economic feasibility of such an exercise from a commercial perspective. Sampling of the biomass was done at 31 representative sites within the Nelson Mandela Metropolitan Municipality, South Africa. The cost of the operation was carefully monitored, documented and reported at each stage, and compared to the cost of replacing the thermal coal currently used by industry within this municipality. The project proved to be financially viable, but only when the energy entrepreneur forms a partnership with the WfW programme, and then only under specific conditions. The project has, however, very high socio-economic returns with respect to a reduction in environmental externalities and job creation.

Highlights

Woody invasive alien plants (IAPs) pose significant direct threats to South Africa’s ecosystems and the services they provide, including water, land productivity and biodiversity.[1,2,3,4,5] These threats are being addressed by the Working for Water (WfW) programme which aims to control invasions as well as provide work and training for unskilled people
While extremely large in and by themselves, these figures still exclude some externalities like noise pollution, damage to roads and damage caused by ash lagoons on water resources
Invasive alien plants are widespread in South Africa and pose a major threat to the country’s water sources and biodiversity as well as threatening lives and infrastructure by being fire prone

Summary

Introduction

Woody invasive alien plants (IAPs) pose significant direct threats to South Africa’s ecosystems and the services they provide, including water, land productivity and biodiversity.[1,2,3,4,5] These threats are being addressed by the Working for Water (WfW) programme which aims to control invasions as well as provide work and training for unskilled people. Studies have shown that some of these effects include the impact of air pollution on human health, the impact of climate change and the environmental impact on water quantity and quality and on biodiversity.[6,7,8,9,10,11] A number of studies have quantified the externality costs of mining coal and transporting it to the Kusile coal-fired power station in eMalahleni, Mpumalanga Province of South Africa[6,7,8,9] (see Letsoalo et al.[12] and O’Farrell et al.[13] for a discussion on the value of natural resources and the difficulties of their quantification). While extremely large in and by themselves, these figures still exclude some externalities like noise pollution, damage to roads and damage caused by ash lagoons on water resources

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