This chapter discusses recent trends in management of postuse wood products and gives an overview of benefits and constraints associated with effective end-of-life management of wood. It highlights the implications of postuse wood management from resource efficiency and climate perspectives. Primary energy and GHG balances are important metrics to understand the resource efficiency of climate change mitigation strategies involving postuse wood products. The chapter describes mechanisms through which postuse management of recovered wood materials can affect primary energy use and GHG impacts of wood products. To further understand the implications of different postuse management options for wood products, we then explore several quantitative scenarios. There is potential for efficient management of postuse wood products by directing these resources to cascade uses including reuse, recycling, and energy recovery. This can offer significant opportunities to improve resource efficiency and reduce greenhouse gas emissions in the built environment.

Heavy trucks contribute significantly to climate change, and in 2020 were responsible for 7% of total Swedish GHG emissions and 5% of total global CO2 emissions. Here we study the full lifecycle of cargo trucks powered by different energy pathways, comparing their biomass feedstock use, primary energy use, net biogenic and fossil CO2 emission and cumulative radiative forcing. We analyse battery electric trucks with bioelectricity from stand-alone or combined heat and power (CHP) plants, and pathways where bioelectricity is integrated with wind and solar electricity. We analyse trucks operated on fossil diesel fuel and on dimethyl ether (DME). All energy pathways are analysed with and without carbon capture and storage (CCS). Bioelectricity and DME are produced from forest harvest residues. Forest biomass is a limited resource, so in a scenario analysis we allocate a fixed amount of biomass to power Swedish truck transport. Battery lifespan and chemistry, the technology level of energy supply, and the biomass source and transport distance are all varied to understand how sensitive the results are to these parameters. We find that pathways using electricity to power battery electric trucks have much lower climate impacts and primary energy use, compared to diesel- and DME-based pathways. The pathways using bioelectricity with CCS result in negative emissions leading to global cooling of the earth. The pathways using diesel and DME have significant and very similar climate impact, even with CCS. The robust results show that truck electrification and increased renewable electricity production is a much better strategy to reduce the climate impact of cargo transport than the adoption of DME trucks, and much more primary energy efficient. This climate impact analysis includes all fossil and net biogenic CO2 emissions as well as the timing of these emissions. Considering only fossil emissions is incomplete and could be misleading.

We analyze conventional retrofit building materials, aluminum, rock, and glass wool materials and compared such materials with wood-based materials to understand the lifecycle primary energy implications of moving from non-renewable to wood-based materials. We calculate cost optimum retrofit measures for a multi-apartment building in a lifecycle perspective, and lifecycle primary energy savings of each optimized measure. The retrofit measures consist of the thermal improvement of windows with varied frame materials, as well as extra insulation of attic floor, basement walls, and external walls with varied insulation materials. The most renewable-based heat supply is from a bioenergy-based district heating (DH) system. We use the marginal cost difference method to calculate cost-optimized retrofit measures. The net present value of energy cost savings of each measure with a varied energy performance is calculated and then compared with the calculated retrofit cost to identify the cost optimum of each measure. In a sensitivity analysis, we analyze the cost optimum retrofit measures under different economic and DH supply scenarios. The retrofit costs and primary energy savings vary somewhat between non-renewable and wood-based retrofit measures but do not influence the cost optimum levels significantly, as the economic parameters do. The lifecycle primary use of wood fiber insulation is about 76% and 80% less than for glass wool and rock wool, respectively. A small-scale DH system gives higher primary energy and cost savings compared to larger DH systems. The optimum final energy savings, in one of the economic scenarios, are close to meeting the requirements in one of the Swedish passive house standards.

Building renovation is considered a key strategy to facilitating the transition towards a renewable energy system, mitigating climate change and addressing energy poverty. However, the rate of buildings undergoing deep energy retrofit in Europe is below 1% per year. The study analyses the life cycle cost and primary energy impacts to retrofit a residential building to an annual final energy use of 50 and 30 kWh/m2, respectively, corresponding to two Swedish passive house standards. The retrofit includes the thermal improvement of the building envelope, and the increased efficiency of water taps and ventilation system. We assume the use of different retrofit materials. The study also analyses the effects of various energy scenarios for district heating and electricity on the primary energy savings and costs of the building retrofit. Finally, we compare the economic net present value (NPV) of the net primary energy savings due to the retrofit options and the cost of them. Retrofit to 50 kWh/m2 is cost efficient while the 30 kWh/m2 level is close to be cost efficient for higher biomass prices. The primary energy use to produce the retrofit options is much smaller in all cases than the operation primary energy savings of them. The cost of different retrofit material versions is similar while the production primary energy use is much lower for wood based materials. Different electricity production scenarios affect the net primary energy savings but are marginal in terms of costs.

Here we compare the biomass feedstock use, primary energy use, net CO2 emission, and cumulative radiative forcing of passenger cars powered by different energy pathways. We consider the full lifecycle of the vehicles, including manufacture and operation. We analyze battery electric vehicles (BEVs) powered by standalone electricity generation using woody biomass, with and without CCS, and with integration of wind electricity. We analyze internal combustion vehicles (ICVs) powered by fossil gasoline and by biomethanol derived from woody biomass, with and without carbon capture and sequestration (CCS). Our system boundaries include all fossil and biogenic emissions from technical systems, and the avoided decay emissions from harvest residue left in the forest. We find that the pathways using electricity to power BEVs have strongly lower climate impacts, compared to the liquid-fueled ICV pathways using biomethanol and gasoline. The pathways using bioelectricity with CCS result in negative emissions leading to global cooling. The pathways using gasoline and biomethanol have substantial climate impact, even with CCS. Regardless of energy pathway, smaller cars have consistently lower climate impact than larger cars. These findings suggest that accelerating the current trend toward vehicle electrification, together with scaling up renewable electricity generation, is a wise strategy for climate-adapted passenger car transport. (C) 2021 The Author(s). Published by Elsevier Ltd.

Abstract The scientific literature contains contrasting findings about the climate effects of forest bioenergy, partly due to the wide diversity of bioenergy systems and associated contexts, but also due to differences in assessment methods. The climate effects of bioenergy must be accurately assessed to inform policy-making, but the complexity of bioenergy systems and associated land, industry and energy systems raises challenges for assessment. We examine misconceptions about climate effects of forest bioenergy and discuss important considerations in assessing these effects and devising measures to incentivize sustainable bioenergy as a component of climate policy. The temporal and spatial system boundary and the reference (counterfactual) scenarios are key methodology choices that strongly influence results. Focussing on carbon balances of individual forest stands and comparing emissions at the point of combustion neglect system-level interactions that influence the climate effects of forest bioenergy. We highlight the need for a systems approach, in assessing options and developing policy for forest bioenergy that: (1) considers the whole life cycle of bioenergy systems, including effects of the associated forest management and harvesting on landscape carbon balances; (2) identifies how forest bioenergy can best be deployed to support energy system transformation required to achieve climate goals; and (3) incentivizes those forest bioenergy systems that augment the mitigation value of the forest sector as a whole. Emphasis on short-term emissions reduction targets can lead to decisions that make medium- to long-term climate goals more difficult to achieve. The most important climate change mitigation measure is the transformation of energy, industry and transport systems so that fossil carbon remains underground. Narrow perspectives obscure the significant role that bioenergy can play by displacing fossil fuels now, and supporting energy system transition. Greater transparency and consistency is needed in greenhouse gas reporting and accounting related to bioenergy.

Forests can help mitigate climate change in different ways, such as by storing carbon in forest ecosystems, and by producing a renewable supply of material and energy products. We analyse the climate implications of different scenarios for forestry, bioenergy and wood construction. We consider three main forestry scenarios for Kronoberg County in Sweden, over a 201-year period. The Business-as-usual scenario mirrors today’s forestry while in the Production scenario the forest productivity is increased by 40% through more intensive forestry. In the Set-aside scenario 50% of forest land is set-aside for conservation. The Production scenario results in less net carbondioxide emissions and cumulative radiative forcing compared to the other scenarios, after an initial period of 30–35 years during which the Set-aside scenario has less emissions. In the end of the analysed period, the Production scenario yields strong emission reductions, about ten times greater than the initial reduction in the Set-aside scenario. Also, the Set-aside scenario has higher emissions than Business-as-usual after about 80 years. Increasing the harvest level of slash and stumps results in climate benefits, due to replacement of more fossil fuel. Greatest emission reduction is achieved when biomass replaces coal, and when modular timber buildings are used. In the long run, active forestry with high harvest and efficient utilisation of biomass for replacement of carbon-intensive non-wood products and fuels provides significant climate mitigation, in contrast to setting aside forest land to store more carbon in the forest and reduce the harvest of biomass.

In recent years, several comparative life cycle analyses have shown that increasing the use of wood in buildings can reduce the life cycle primary energy use and carbon emission of buildings. This study reviews the life cycle inventory methodology of primary energy use and carbon emissions, based on ecoinvent database, considering different modelling choices for (i) materials heating values; (ii) biogenic carbon; (iii) calcination and carbonation processes; (iv) electricity production scenarios; (v) impact distribution of multi-functional processes; (vi) post-use benefits. The analysis relates to the standards while the implication of different modelling choice is shown by comparing the primary energy use and carbon emission in the production and end-of-life stages of a multi-storey residential building with concrete, cross laminated timber and modular timber structures, respectively. The results highlight the displacement between different modelling choices in terms of primary energy use and carbon emissions. Such modelling options especially influence the LCA results in the product stage and beyond the end of life stage, and especially wood- and/or cement-based materials.

Here, we analyse final and primary energy savings and overheating risk of deep energy renovation of a Swedish multi-storey residential building of the 1970s under climate change and consider overheating control measures to reduce cooling demand and risk of overheating. The energy-efficiency measures include additional insulation to basement walls, exterior walls, and attic floor as well as improved energy-efficient windows and doors, balanced ventilation with heat recovery (VHR), lighting, household appliances as well as water taps and shower heads. The future climates are based on the representative concentration pathways scenarios. We find that implementing improved energy-efficient windows and doors, VHR and additional insulation to external walls give significant final and primary energy savings for space heating. The total operation final and primary energy use decrease averagely by 58% and 54%, respectively when all the measures are cumulatively applied under both current and future climate scenarios. Efficient household appliances and lighting as well as appropriate overheating control measures significantly reduce cooling demand and risk of overheating. The indoor air temperature and overheating risk as well as the final energy savings are influenced by the considered climate scenarios. (C) 2020 Elsevier Ltd. All rights reserved.