Domestic heating from forest logging residues: environmental risks and benefits

Abstract

The European Union (EU) relies largely on bioenergy to achieve its climate and energy targets for 2020\ud and beyond. Special focus is placed on utilization of biomass residues, which are considered to cause low\ud environmental impacts.\ud We used the dataset from the latest European Commission document on the sustainability of solid and\ud gaseous biomass (SWD2014 259), complementing those results by: i) designing three pathways for\ud domestic-heat production using forest logging residues, with different combustion technologies; ii)\ud expanding the analysis to include forest carbon stock development with and without bioenergy; iii)\ud using absolute climate metrics to assess the surface temperature response by the end of the century to a\ud bioenergy and a reference fossil system; iv) including multiple climate forcers (well-mixed GHG, near\ud term climate forcers and surface albedo change); iv) quantifying life cycle impacts on acidification,\ud particulate matter emissions and photochemical ozone formation; v) reviewing potential risks for forest\ud ecosystem degradation due to increased removal of residues.\ud Supply-chain GHG savings of the three pathways analysed ranged between 80% and 96% compared to a\ud natural gas system, above the 70% threshold suggested by the EU. However, the climate impact of bioenergy\ud should be assessed by considering also the non-bioenergy uses of the biomass and by including\ud all climate forcers.\ud We calculate the Surface Temperature Response to bioenergy and fossil systems by means of Absolute\ud Global surface Temperature Potential (AGTP) metric. Domestic heating from logging residues is generally\ud beneficial to mitigate the surface temperature increase by 2100 compared to the use of natural gas and\ud other fossil sources. As long as residues with a decay rate in the forest higher than 2.7%*yr1 are\ud considered as feedstock, investing now in the mobilization of residues for heat production can reduce the\ud temperature increase by 2100 compared to all the fossil sources analysed, both in case of bioenergy as a\ud systemic change or in case of bioenergy as a transitory option.\ud Furthermore, several environmental risks are associated with the removal and use of forest logging\ud residues for bioenergy. These issues concern mostly local air pollution, biodiversity loss and, mainly for\ud stumps removal, physical damage to forest soils.\ud Forest logging residues are not free of environmental risks. Actions promoting their use should\ud consider: (i) that climate change mitigation depends mainly on the decay rate of biomass under natural\ud decomposition and time and rate of technology deployment, (ii) whether management guidelines aimed\ud at protecting long-term forest productivity are in place and (iii) whether proper actions for the management\ud of adverse effects on local air pollution are in place

Time‐dependent climate impact and energy efficiency of combined heat and power production from short‐rotation coppice willow using pyrolysis or direct combustion

“…A few studies have used DT S as an indicator for the time-dependent climate impacts of bioenergy systems (e.g. Cherubini et al, 2013;Ericsson et al, 2013Hammar et al, 2014Hammar et al, , 2015Giuntoli et al, 2015;Ortiz et al, 2016;Pors€ o et al, 2016), but to our knowledge, no such study has been presented on pyrolysis-based bioenergy systems. However, several authors have investigated the climate impact and energy efficiency of pyrolysis-based bioenergy systems from a life cycle perspective based on GWP (Gaunt and Lehmann, 2008;Roberts et al, 2010;Hammond et al, 2011;Hanandeh, 2012;Ibarrola et al, 2012;Wang et al, 2013;Peters et al, 2015;Thornley et al, 2015).…”

From the allocation debate to a substitution paradox in waste bioenergy life cycle assessment studies

“…On the other hand, only two studies (Negro et al 2017;Li et al 2018) selected a mass unit as the functional unit. In addition, 4 out of the 16 studies explicitly stated the use of attributional ELCA (Boulamanti et al 2013;Agostini et al 2015;Giuntoli et al 2015Giuntoli et al , 2016 but all 16 studies conducted the ELCA in a consequential manner. The authors decided to modify the waste management practice of the original system, modelling an alternative end-use of the investigated waste feedstock.…”

Future Developments Without Targeted Policies

“…There are also both synergistic effects and trade-offs between air pollution and climate policy. One example of a possible trade-off is that burning biomass as a low-carbon energy source can lead to more air pollution if appropriate air quality management practices are not put in place (Giuntoli et al 2015). Another is that diesel cars emit less CO 2 than petrol (gasoline) cars but emit more PM (Mazzi and Dowlatabadi 2007;Tanaka et al 2012;O'Driscoll et al 2018).…”