Michael Penev

Leveling Intermittent Renewable Energy Production Through Biomass Gasification-Based Hybrid Systems

The increased use of intermittent renewable power in the United States is forcing utilities to manage increasingly complex supply and demand interactions. This paper evaluates biomass pathways for hydrogen production and how they can be integrated with renewable resources to improve the efficiency, reliability, dispatchability, and cost of other renewable technologies. Two hybrid concepts were analyzed that involve co-production of gaseous hydrogen and electric power from thermochemical biorefineries. Both of the concepts analyzed share the basic idea of combining intermittent wind-generated electricity with a biomass gasification plant. The systems were studied in detail for process feasibility and economic performance. The best performing system was estimated to produce hydrogen at a cost of

Production of Synthetic Natural Gas from Carbon Dioxide and Renewably Generated Hydrogen: A Techno-Economic Analysis of a Power-to-Gas Strategy

1.67/kg. The proposed hybrid systems seek to either fill energy shortfalls by supplying hydrogen to a peaking natural gas turbine or to absorb excess renewable power during low-demand hours. Direct leveling of intermittent renewable electricity production is accomplished with either an indirectly heated biomass gasifier, or a directly heated biomass gasifier. The indirect gasification concepts studied were found to be cost competitive in cases where value is placed on controlling carbon emissions. A carbon tax in the range of

Evaluation of Synthetic Natural Gas Production From Renewably Generated Hydrogen and Carbon Dioxide

26–40 per metric ton of CO2 equivalent (CO2 e) emission makes the systems studied cost competitive with steam methane reforming (SMR) to produce hydrogen. However, some additional value must be placed on energy peaking or sinking for these plants to be economically viable. The direct gasification concept studied replaces the air separation unit (ASU) with an electrolyzer bank and is unlikely to be cost competitive in the near future. High electrolyzer costs and wind power requirements make the hybridization difficult to justify economically without downsizing the system. Based on a direct replacement of the ASU with electrolyzers, hydrogen can be produced for

Production of Fischer–Tropsch liquid fuels from high temperature solid oxide co-electrolysis units

0.27 premium per kilogram. Additionally, if a non-renewable, grid-mix electricity is used, the hybrid system is found to be a net CO2 e emitter.Copyright

Design and technoeconomic performance analysis of a 1MW solid oxide fuel cell polygeneration system for combined production of heat, hydrogen, and power

Power-to-gas to energy systems are of increasing interest for low carbon fuels production and as a low-cost grid-balancing solution for renewables penetration. However, such gas generation systems are typically focused on hydrogen production, which has compatibility issues with the existing natural gas pipeline infrastructures. This study presents a power-to-synthetic natural gas (SNG) plant design and a techno-economic analysis of its performance for producing SNG by reacting renewably generated hydrogen from lowtemperature electrolysis with captured carbon dioxide. The study presents a “bulk” methanation process that is unique due to the high concentration of carbon oxides and hydrogen. Carbon dioxide, as the only carbon feedstock, has much different reaction characteristics than carbon monoxide. Thermodynamic and kinetic considerations of the methanation reaction are explored to design a system of multistaged reactors for the conversion of hydrogen and carbon dioxide to SNG. Heat recuperation from the methanation reaction is accomplished using organic Rankine cycle (ORC) units to generate electricity. The product SNG has a Wobbe index of 47.5 MJ/m and the overall plant efficiency (H2/ CO2 to SNG) is shown to be 78.1% LHV (83.2% HHV). The nominal production cost for SNG is estimated at 132

Electrochemical device for syngas and liquid fuels production

/MWh (38.8

Meeting the Needs of Hydrogen Infrastructure: Financial and Sustainability Analysis

/MMBTU) with 3

Low-Carbon Natural Gas for Transportation: Well-to-Wheels Emissions and Potential Market Assessment in California

/kg hydrogen and a 65% capacity factor. At U.S. DOE target hydrogen production costs (2.2

Expanded Capabilities for the Hydrogen Financial Analysis Scenario Tool (H2FAST)

/kg), SNG cost is estimated to be as low as 97.6

Overview of the Hydrogen Financial Analysis Scenario Tool (H2FAST); NREL (National Renewable Energy Laboratory)

/MWh (28.6