Search

• Renewable natural gas (RNG) production through biomass gasification was assessed. • Six feedstocks (corn stover (CS), wheat straw, whole forest, forest residues, cow manure, and the organic fraction of municipal solid waste (OFMSW) were studied. • Data-intensive process models were developed to understand the mass and energy balances of the conversion process. • RNG production costs are lowest for the OFMSW and CS. • The lowest cost of RNG production, $6.28/GJ, is higher than natural gas price in North America. Renewable natural gas (RNG) from biomass can be used as an alternative to natural gas. However, there is limited understanding of the economic viability of RNG production from a wide range of feedstocks. In this study, a comprehensive comparative techno-economic assessment of RNG production via gasification from six biomass feedstocks with a wide range of moisture contents and characteristics was conducted. The feedstocks studied are corn stover (CS), wheat straw (WS), whole forest (WF), forest residues (FR), cow manure (CM), and the organic fraction of municipal solid waste (OFMSW). The RNG production plants were simulated and the simulation results were used to develop techno-economic models for each feedstock to estimate the production cost of RNG. The pathways were compared in terms of RNG yield, RNG production quantity, electricity generation, as well as RNG production costs and cost components. Sensitivity analyses were conducted on a wide range of factors and effect of including cardon credit on the production cost were studied. RNG production costs from the gasification of the OFMSW and CS were lower than those of other feedstocks at 6.28 $/GJ and 6.32 $/GJ, respectively. If the avoided cost (as a source of revenue) of landfilling of the OFMSW or carbon credit (minimum 90 $/t CO 2) is considered, the RNG production cost can be competitive with natural gas price (1.4 $/GJ). The information developed in study is critical for decision makers in policy formulation and investment decisions. [ABSTRACT FROM AUTHOR]

Biomass fuels have long been accepted as useful renewable energy sources, especially in mitigating greenhouse gases (GHG), nitrogen oxides, and sulfur oxide emissions. Biomass fuel is carbon neutral and is usually low in both nitrogen and sulfur. For the past decade, various forms of biomass fuels have been co-combusted in existing coal-fired boilers and gas-fired power plants. Biomass is used as a supplemental fuel to substitute for up to 10% of the base fuel in most full commercial operations. There are several successful co-firing projects in many parts of the world, particularly in Europe and North America. However, despite remarkable commercial success in Europe, most of the biomass co-firing in North America is limited to demonstration levels. This review takes a detailed look at several aspects of biomass co-firing with a direct focus on North America. It also explores the benefits, such as the reduction of GHG emissions and its implications. This paper shows the results of our studies of the biomass resources available in North America that can be used in coal-fired boilers, their availability and transportation to the power plant, available co-firing levels and technologies, and various technological and environmental issues associated with biomass co-firing. Finally, the paper proffers solutions to help utility companies explore biomass co-firing as a transitional option towards a completely carbon-free power sector in North America. [ABSTRACT FROM AUTHOR]

Canada has many isolated communities that are not connected to the electrical grid. Most of these communities meet their electricity demand through stand-alone diesel generators. Diesel generators have economic and environmental concerns that can be minimized by using hybrid renewable energy technologies. This study aims to assess the implementation of a hybrid energy system for an off-grid community in Canada and to propose the best hybrid energy combination to reliably satisfy electricity demand. Seven scenarios were developed: 1) 100% renewable resources, 2) 80% renewable resources, 3) 65% renewable resources, 4) 50% renewable resources, 5) 35% renewable resources, 6) 21% renewable resources, and 7) battery-diesel generators (0% renewable resources). A case study for the remote community of Sandy Lake, Ontario, was conducted. Hybrid systems were chosen to meet the requirements of a 4.4 MWh/day primary load with a 772 kW peak load. Sensitivity analyses were carried out to assess the impact of solar radiation, wind speed, diesel price, CO 2 penalty cost, and project interest rate on optimum results. A GHG (greenhouse gas) abatement cost was assessed for each scenario. Considering GHG emission penalty cost, the costs of electricity for the seven scenarios are $1.48/kWh, $0.62/kWh, $0.54/kWh, $0.42/kWh, $0.39/kWh, $0.37/kWh, and $0.36/kWh. [ABSTRACT FROM AUTHOR]