Renewable energy resource assessment

© The Author(s) 2019. Literature overview of published global and regional renewable energy potential estimates. This section provides definitions for different types of RE potentials and introduces a new category, the economic renewable energy potential in space constrained environments. The potential for utility scale solar and onshore wind in square kilometre and maximum possible installed capacity (in GW) are provided for 75 different regions. The results set the upper limits for the deployment of solar- and wind technologies for the development of the 2.0 °C and 1.5 °C energy pathways

Comparison of biomass component equations for four species of northern coniferous tree seedlings

We compare equations predicting the biomass components (foliage, branches, stem, roots, total aboveground and total tree) for seedlings of four coniferous tree species: jack pine (Pinus banksiana Lamb.), red pine (Pinus resinosa Ait.), eastern white pine (Pinus strobus L.) and black spruce (Picea mariana (Mill.) B.S.P.) grown under controlled experimental conditions for 3 years. Coefficients of determination (R2) for the component equations exceeded 0.9 for jack and red pine, and ranged from 0.7 to 0.9 for white pine and black spruce. Basal diameter was the most important variable in all equations. Adding crown width improved the adjusted R2 for total, aboveground, branch and foliage biomass equations by 2.5 %. Adding tree height improved the adjusted R2 for stem biomass equations by 6.2 %. Root biomass equations were not improved by including height or crown width. Using statistical comparisons of the full model (i.e. separate equations for each species) with three alternative reduced models that pooled various combinations of species, we determined that none of the biomass component equations could be combined among the four conifer species. (© Inra/Elsevier, Paris.)Comparaison d'équations des composantes de la biomasse pour des jeunes plants de quatre espèces de conifères canadiens. Nous avons développé et comparé des équations de prédiction des composantes de la biomasse (feuillage, branches, tronc, racines, total aérien et total arbre) pour des jeunes plants de quatre espèces de conifères: pin gris (Pinus banksiana Lamb.), pin rouge (Pinus resinosa Ait.), pin blanc (Pinus strobus L.) et épicéa noir (Picea mariana (Mill.) B.S.P) cultivés sous conditions expérimentales controlées pendant trois ans. Les coefficients de détermination (R2) pour les équations des composantes excèdent 0,9 pour le pin gris et le pin rouge, et varient entre 0,7 et 0,9 pour le pin blanc et l'épicéa noir. Le diamètre basal était la variable la plus importante dans toutes les équations. L'ajout de la largeur de la couronne améliore de 2,5 % le R2 ajusté pour les équations du total, de l'aérien, des branches et du foliage. L'ajout de la hauteur de l'arbre améliore le R 2 ajusté de 6,2 % pour la biomasse du tronc. Les équations de la biomasse racinaire n'étaient pas améliorées par l'ajout de la largeur de la couronne ou la hauteur. En utilisant des comparaisons statistiques du modèle entier (i.e., équations séparées pour chaque espèce) avec trois modèles simplifiés qui regroupent différentes combinaisons d'espèces, nous avons déterminé qu'aucune équations des composantes de la biomasse ne pouvaient être combinées pour décrire plus d'une espèce. (© Inra/Elsevier, Paris.

Duration of Climate Change Mitigation Benefits from Increasing Boreal Forest Harvest Age by 10 Years

We presented a case study and associated method for stand scale assessment of the duration of the climate change mitigation benefit provided by increasing forest harvest age (i.e., the age a stand is harvested). We used stand yield curves and newly developed equations to estimate carbon stocks in various boreal forest ecosystem pools in Ontario, Canada. The proposed method was applied to forest identified as available for harvesting in management plans for three forest management units with a combined area of more than 1900 km2. Our analysis indicated that a 10-year increase in harvest age did not provide a mitigation benefit (reduced carbon stock) in about half the available harvest area (45.5%, 61.9%, and 62.1% of the total available harvest area in the management units). Increasing the harvest age by 10 years resulted in a mitigation benefit lasting longer than 25 years for 15.1%, 16.0%, and 13.0% of the total available harvest area in the management units. The results suggest that increasing harvest age may have limited mitigation potential in Ontario’s managed boreal forests in the short-term but can reduce overall carbon stocks in the longer term

Duration of Climate Change Mitigation Benefits from Increasing Boreal Forest Harvest Age by 10 Years

We presented a case study and associated method for stand scale assessment of the duration of the climate change mitigation benefit provided by increasing forest harvest age (i.e., the age a stand is harvested). We used stand yield curves and newly developed equations to estimate carbon stocks in various boreal forest ecosystem pools in Ontario, Canada. The proposed method was applied to forest identified as available for harvesting in management plans for three forest management units with a combined area of more than 1900 km2. Our analysis indicated that a 10-year increase in harvest age did not provide a mitigation benefit (reduced carbon stock) in about half the available harvest area (45.5%, 61.9%, and 62.1% of the total available harvest area in the management units). Increasing the harvest age by 10 years resulted in a mitigation benefit lasting longer than 25 years for 15.1%, 16.0%, and 13.0% of the total available harvest area in the management units. The results suggest that increasing harvest age may have limited mitigation potential in Ontario’s managed boreal forests in the short-term but can reduce overall carbon stocks in the longer term

Does Earlier and Increased Spring Plant Growth Lead to Reduced Summer Soil Moisture and Plant Growth on Landscapes Typical of Tundra-Taiga Interface?

Over the past four decades, satellite observations have shown intensified global greening. At the same time, widespread browning and reversal of or stalled greening have been reported at high latitudes. One of the main reasons for this browning/lack of greening is thought to be warming-induced water stress, i.e., soil moisture depletion caused by earlier spring growth and increased summer evapotranspiration. To investigate these phenomena, we use MODIS collection 6, Global Inventory Modeling and Mapping Studies third-generation (GIMMS) normalized difference vegetation index (NDVI3g), and Global Land Evaporation Amsterdam Model (GLEAM) satellite-based root-zone soil moisture data. The study area was the Far North of Ontario (FNO), 453,788 km2 of heterogeneous landscape typical of the tundra-taiga interface, consisting of unmanaged boreal forests growing on mineral and peat soils, wetlands, and the most southerly area of tundra. The results indicate that the increased plant growth in spring leads to decreased summer growth. Lower summer soil moisture is related to increased spring plant growth in areas with lower soil moisture content. We also found that earlier start of growing season leads to decreased summer and peak season maximum plant growth. In conclusion, increased spring plant growth and earlier start of growing season deplete summer soil moisture and decrease the overall summer plant growth even in temperature-limited high latitude ecosystems. Our findings contribute to evolving understanding of changes in vegetation dynamics in relation to climate in northern high latitude terrestrial ecosystems

Stem profile equations for young trembling aspen in northern Ontario

Stem profile equations were developed for young trembling aspen (Populus tremuloides Michx.) growing on 6 different sites in northern Ontario. The objective was to develop a model using stem diameter at any height to predict stem diameter at other heights and then compare the model among sites. The 262 sample trees were split into calibration (180) and validation (82) sets. Four stem profile models having from 1 to 3 parameters were tested for parameter significance for each site, and then compared among sites. Data analysis was performed using bootstrap methods. One of the 4 models was not significantly different (P > 0.278) among sites. Validation of this model produced mean prediction errors and mean relative prediction errors of less than 0.001 cm and 0.09%, respectively; standard deviations of these errors were 0.15 cm and 4.09%, respectively. The presented method can be used to develop stem profile equations that are applicable to a broad range of growing conditions.Équations de profil de tige de jeunes trembles de l’Ontario septentrional. On a mis au point des équations de profil de tige pour des trembles (Populus tremuloides Michx.) se développant dans 6 stations différentes du nord de l’Ontario. L’objectif était de créer un modèle utilisant le diamètre pris à n’importe quelle hauteur pour prédire le diamètre à d’autres hauteurs et ensuite pour comparer les modèles selon les sites. Les 262 arbres témoins ont été affectés soit au calibrage (180) soit à la validation (82). Sur quatre modèles comportant de 1 à 3 paramètres, on a d’abord testé le caractère significatif des paramètres dans chaque site, puis procédé à des comparaisons entre sites. Pour l’analyse des données on a utilisé les méthodes « bootstrap ». L’un des 4 modèles ne présentait pas de différence significative (P > 0,278) entre sites. La validation de ce modèle inique une prédiction d’erreur moyenne et d’erreur relative moyenne respectivement inférieurs à 0,001 cm et 0,09 %. Les écarts types de ces erreurs étaient de 0,15 cm et 4,09 %. La méthode présentée peut être utilisée pour développer des équations de profil de tige applicables à une vaste gamme de conditions de croissance

Can Wood Pellets from Canada’s Boreal Forest Reduce Net Greenhouse Gas Emissions from Energy Generation in the UK?

We present the results of a study on the climate forcing effects of replacing coal for power generation in the United Kingdom (UK) with wood pellets produced in northern Ontario, Canada. Continuous wood pellet production from two biomass sources were considered: fiber from increased harvesting of standing live trees (stemwood scenario) and from harvest residue provided by ongoing harvesting operations (residue scenario). In both scenarios, biomass was collected from harvesting operations in two forest management units (FMUs) with contrasting harvest residue treatments: natural decay of slash piles in the Hearst FMU and slash pile burning in the Kenora FMU. Life cycle emissions associated with wood pellets were assessed for production, transportation, and combustion to replace coal at a hypothetical power generating station in the UK. Greenhouse gas (GHG) emissions and removals in wood pellet and coal scenarios were assessed using two methods: global warming potential (GWP)-based mass balance and dynamic life cycle assessment (LCA) approaches. In the stemwood scenario, climate change mitigation from replacing coal with wood pellets was not achieved within the study timeline (2020–2100). In the residue scenario, immediate climate change mitigation was achieved with fiber sourced from the Kenora FMU where the current practice is to burn slash piles; for the Hearst FMU, where slash is allowed to decompose in the forest, climate change mitigation occurred 11.6 and 3.1 years after biomass collection began, as assessed by the mass balance and dynamic LCA methods, respectively. Factors affecting mitigation potential in the studied scenarios are discussed