• Energy Research
• 13. Climate action close
• Polytechnique Montréal close

Forests are an increasingly important source of feedstock for bioenergy as global efforts to mitigate atmospheric CO2 concentrations increase. In keeping with the principles of sustainable forest management, it is important that feedstock procurement not have negative impacts on the environment, including biodiversity. Impacts of land use, including forest management, can be evaluated along all stages in the production of these goods and services, using life cycle assessment (LCA), which is a potentially powerful tool for organizing and evaluating the impacts of production. There is growing recognition of the need to integrate land‐use impacts into LCA for forest products such as bioenergy, especially on biodiversity. Integrating quantitative indicators of biodiversity into LCAs of biomass production systems is particularly challenging because biodiversity is a multidimensional concept that can never be fully represented by a single number, and yet many proposed approaches rely on this. Reliance on a single metric oversimplifies ‘biodiversity’ and might lead to inappropriate conclusions on local land management practices. LCA is not suited to providing reliable site‐specific assessment of forest product systems in regard to the complexities of biodiversity. Nevertheless, the global and comprehensive nature of LCA makes it a useful tool for preventing a shift in environmental problems or burdens across the value chain because of local land management decisions. In this context, complementary site‐specific and/or regional studies or analyses may help mitigate against inaccurate conclusions being drawn from LCA. WIREs Energy Environ 2016, 5:670–683. doi: 10.1002/wene.211This article is categorized under: Bioenergy > Climate and Environment Energy and Development > Climate and Environment

Abstract Flared and vented natural gas in remote regions of the world contribute ?1% of the total CO2 emissions. High investment costs to build facilities to treat this gas and labor costs to operate the infrastructure are deterrents to addressing this environmental burden. Here we report a techno-economic analysis of a commercial mobile manufacturing plant that processes 2400 m3 d-1 of methane via a tandem short contact time catalytic partial oxidation (CPOX) and a single-pass Fischer–Tropsch fluidized bed to produce 7 bbl d-1. Starting from methane and air, a thermodynamic analysis identified the optimized operating conditions considering both carbon yield, CO/H2 ratio and adiabatic conditions. We studied the flammability limits of the mixture at operating pressures and temperatures. The economic analysis itemizes costs for all equipment rather than applying scale-up power law or factors. The greatest contributors to direct costs are the compressors and the CPOX reactor. Operating CPOX at 2.0 MPa reduces reactor volumes but to achieve 90% conversion and selectivity requires operating this unit above 900 °C. Avoiding syngas compression and upstream syngas conditioning reduces capital costs. The capital cost (CAPEX) reaches 570 000 USD when the whole process operates at 2.0 MPa. Considering numbering-up, the price of the 100th unit approaches 360 000 USD thus the MRU increases profitability. We demonstrate how thermodynamics constrains methane conversion and syngas selectivity. A large part of achieving low CAPEX is operating a single pass process, building multiple units, and replacing the methane to heat the treater at the oil tank battery with the incondensable gas leaving the three phases separator downstream the Fischer–Tropsch reactor.

In a context of energy transition towards renewable energies, this case study situated in Madagascar allows us to verify the extent to which an on-grid photovoltaic solar power plant represents a vector for sustainable development. The article proposes a model for assessing sustainability from a qualitative multi-criteria perspective. This analysis fits into the theoretical question of the science of sustainability by challenging the theory of endogenous development. The innovation of this research is based on the use of a qualitative approach to a technological issue filling a literature gap in the major issue of the effective sustainability of renewable energy (particularly in the context of an island state). The study emphasizes that the plant can only represent a vector for sustainable development with the collaboration of the concerned parties, which implies considering the electrification needs at the local level. The article confirms that the impacts generated by the power plant can lead to conflicts between different sustainable development goals. Theoretically, the study emphasizes that the evaluation of the sustainability of solar power plants should follow a process that: (i) uses a preferably qualitative methodology likely to understand the local conditions of the communities in which they are established; (ii) identifies dissociated indicators while taking into account the context; and (iii) analyzes the possible negative interactions between the impact areas by highlighting the key areas linked to land management and the well-being of women within a poverty reduction approach.

Abstract Hybrid ground-coupled heat pump systems can efficiently heat and cool buildings by exchanging heat with geological materials. Their sizing is, however, complex and their financial profitability is hard to establish during the design phase due to uncertainties that taint important design parameters. Historically, impacts of uncertainties are assessed after sizing completion using sensitivity analyses. Unfortunately, these analyses cannot mitigate design risks, should the consequences of uncertainties be significant. Here, we show how the net present value-at-risk, a stochastic financial indicator inspired by a metric used in the financial sector, can weave the impacts of uncertainties throughout the design phase. The net present value-at-risk is compared to the net present value in a case study that considers uncertainty of construction costs, building’s heat load, energy tariffs and ground thermal conductivity. Results show that this financial indicator, although it comes at a higher computational price than traditional net present value indicator, leads to shorter payback periods, greatly reduces the risks of unforeseen financial losses and does not require further sensitivity analysis. By describing uncertain parameters with statistical distributions during sizing, the proposed designs are more conservative, still efficient and financially viable while being shielded from worst case scenarios.

Abstract A dynamic simulation model, based upon the thermal-electrical analogy, has been developed to simulate the free thermal behavior of a solar greenhouse. The simple linearized model treats greenhouse air and ground temperatures as lumped parameters. It requires only six input parameters, which were measured on site or obtained from a regional weather-station. Model development focused on radiative transfers through the glazing (i.e. solar input) and within the greenhouse (i.e. re-emitted infrared) and on heat losses by infiltration which were determined experimentally. The model was validated by comparisons with the actual thermal behavior of SERSOL, a solar greenhouse built by students on the campus of the University of Montreal. Data were recorded in SERSOL during 10 days over a 3-month winter period. Several key parameters were adjusted by curve fitting of the results obtained in specially designed experiments. Results obtained over a broad spectrum of weather conditions show good agreement between simulated and actual behavior. The main default of the model appears to be a time shift, which could not be satisfactorily corrected.

Background: In recent years, the integration of renewable energy sources into the grid has increased exponentially. However, one significant challenge in integrating these renewable sources into the grid is intermittency. Objective: To address this challenge, accurate PV power forecasting techniques are crucial for operations and maintenance and day-to-day operations monitoring in solar plants. Methods: In the present work, a hybrid approach that combines Deep Learning (DL) and Numerical Weather Prediction (NWP) with electrical models for PV power forecasting is proposed Results: The outcomes of the study involve evaluating the performance of the proposed model in comparison to a Physical model and a DL model for predicting solar PV power one day ahead and two days ahead. The results indicate that the prediction accuracy of PV power decreases and the error rates increase when forecasting two days ahead, as compared to one day ahead. Conclusion: The obtained results demonstrate that DL models combined with NWP and electrical models can improve PV Power forecasting compared to a Physical model and a DL model.

Abstract The development of integrated forest biorefineries is an attractive alternative for pulp and paper mills as they can increase their revenue by producing biofuels and chemicals in addition to their core products. However, the implementation of any biorefinery technology will alter the energy balance of the pulp mill. The purpose of this study was to evaluate the impact of implementing a hemicellulose extraction and conversion stage into a Canadian hardwood Kraft pulp mill on the energy supply and demand, and to identify measures for process optimization to address any increased energy requirement. An approach for energy optimization is proposed to face the energy shortage of the modified process. The approach takes into account energy efficiency measures, such as optimal use of available energy by maximized internal heat exchange, increased water system closure, improved condensate recovery and implementation of an advanced absorption cycle. The proposed measures reduce the steam demand of the Kraft process and satisfy the increased energy requirement during the implementation of a hemicellulose extraction and conversion process. This study shows that energy optimization should be an integral part of any attempt to successfully convert a conventional Kraft pulp mill into a biorefinery.

AbstractStudy regionThis study is conducted in the Magdalen Islands (Québec, Canada), a small archipelago located in the Gulf of St. Lawrence.Study focusThis work was undertaken to support the design of a long-term groundwater monitoring network and for the sustainable management of groundwater resources. This study relies mostly on the compilation of existing data, but additional field work has also been carried out, allowing for the first time in the Magdalen Islands, direct observation of the depth and shape of the transition zone between freshwater and seawater under natural conditions. Simulations were conducted along a 2D cross-section on Grande Entrée Island in order to assess the individual and combined impacts of sea-level rise, coastal erosion and decreased groundwater recharge on the position of the saltwater–freshwater interface. The simulations were performed considering variable-density flow and solute transport under saturated-unsaturated conditions. The model was driven by observed and projected climate change scenarios to 2040 for the Magdalen Islands.New hydrological insights for the regionThe simulation results show that among the three impacts considered, the most important is sea-level rise, followed by decreasing groundwater recharge and coastal erosion. When combined, these impacts cause the saltwater–freshwater interface to migrate inland over a distance of 37m and to rise by 6.5m near the coast to 3.1m further inland, over a 28-year period.