by Samuel Cruz-Manzo

Received: 31 July 2020;  Published: 24 November 2020;  doi: 10.21926/jept.2004017

In this study, uncertainties during the assessment of the electrochemical impedance spectrum of the polymer electrolyte fuel cell (PEFC) attributed to inductive artefacts at high frequencies and inductive loops at low frequencies as well as oxygen diffusion time constant are discussed. A validated impedance model represented as an equivalent electrical circuit of a PEFC allowed the simulation of the effect of inductive artefacts, inductive loops and oxygen diffusion time constant on electrochemical impedance spectr [...]

by Katarzyna Grubel  , Ji Su  , Jotheeswari Kothandaraman  , Kriston Brooks  , Gabor A. Somorjai  and Tom Autrey

Received: 01 September 2020;  Published: 23 November 2020;  doi: 10.21926/jept.2004016

In this perspective on hydrogen carriers, we focus on the needs for the development of robust active catalysts for the release of H2 from aqueous formate solutions, which are non-flammable, non-toxic, thermally stable, and readily available at large scales at reasonable cost. Formate salts can be stockpiled in the solid state or dissolved in water for long term storage and transport using existing infrastructure. Furthermore, formate salts are readily regenerated at moderate pressures using the same catalyst as for [...]

by Jacob Ladenburg

Received: 28 April 2020;  Published: 12 August 2020;  doi: 10.21926/jept.2003015

Visual external costs are significant elements in the cost-benefit analysis of wind farm locations. This has been demonstrated well in the literature. However, in the assessment of the visual costs, a large share of the earlier studies used no or only simplistic visualizations of the visual impacts at stake. The cost estimates thus rely on the respondents’ ability to imagine the visual impacts associated with wind turbines of different sizes and at different locations. This has been argued to potentially reduce the [...]

by Mohammad Jafari  and Zahra Malekjamshidi

Received: 13 June 2020;  Published: 05 August 2020;  doi: 10.21926/jept.2003014

In this paper, a topology of a residential hybrid renewable energy system based on a high-frequency multi-winding transformer is introduced and analyzed. The system includes a PV and a wind-turbine as renewable energy sources, a battery as energy storage and their energies are integrated through a high-frequency transformer. In fact, the transformer integrates the energies in a magnetic form and also isolates the system inputs and outputs. The integrated output from renewables and battery is a DC high-voltage and i [...]

by Najmul Hoque  , Wahidul Biswas  , Ilyas Mazhar  and Ian Howard

Received: 29 June 2020;  Published: 31 July 2020;  doi: 10.21926/jept.2003013

Hydrogen is regarded as a potential solution to address future energy demands and environmental protection challenges. This study assesses the triple bottom line (TBL) sustainability performance of hydrogen as an automotive fuel for Western Australia (WA) using a life cycle approach. Hydrogen is considered to be produced through water electrolysis. Two scenarios, current grid electricity and future renewable-based hydrogen, were compared with gasoline as a base case. The results show that locally produced grid elec [...]

by Peter Leary  , Peter Malin  , Graeme Saunders  and Charles Sicking

Received: 03 December 2019;  Published: 29 July 2020;  doi: 10.21926/jept.2003012

A core feature of convective geothermal resource production is wellbore energy flow Q ~ ρC x T x V. E.g., for wellbore fluid of volume heat capacity ρC ~ 4.3MJ/m3∙oC, temperature T ~ 230oC, and volumetric flow V ~ 50L/s, wellbore heat energy production is Q~ 50MWth ~ 5MWe. Wellbore fluid flow V =2πr0φv0ℓ for open wellbore length ℓ is given in turn by the spatially variable product crustal porosity times crustal fluid velocity v ≡ φv0 at the wellbore radius r0. For a geothermal wellbore to be productive (nominal Q ~ [...]

by Kosmas A. Kavadias  and Stefanos Tzelepis

Received: 03 June 2020;  Published: 24 July 2020;  doi: 10.21926/jept.2003011

The fluctuations in the cost of energy coupled with the gradual decrease in natural resources (i.e., oil, natural gas, coal) and the environmental issues caused by the extensive use of fossil fuels, demand the urgent need for the development of advanced and clean energy systems. The European Union has requested new measures to target climate and energy deterioration by developing renewable energy sources by 2030. The stochastic character of the energy sources and the fluctuation in demand for the energy systems pos [...]

by Ryan J. Clarke  and David A. Miller

Received: 15 April 2020;  Published: 09 June 2020;  doi: 10.21926/jept.2002010

As wind turbine blades grow longer, new design parameters gain additional importance such as blade weight, tip deflection and material cost. These parameters require designers to relook at carbon fiber as a potential design solution. However, the composite materials in wind turbine blades are subjected to significant compressive loading, and the compressive strength of carbon fiber reinforced polymer (CFRP) composites is much lower than its tensile strength. This reduction in compression strength is due to a change [...]

by Camille Tomasso  , Anne L. Pham  , Tracy M. Mattox  and Jeffrey J. Urban

Received: 20 April 2020;  Published: 19 May 2020;  doi: 10.21926/jept.2002009

Hydrogen (H2) shows great promise as zero-carbon emission fuel, but there are several challenges to overcome in regards to storage and transportation to make it a more universal energy solution. Gaseous hydrogen requires high pressures and large volume tanks while storage of liquid hydrogen requires cryogenic temperatures; neither option is ideal due to cost and the hazards involved. Storage in the solid state presents an attractive alternative, and can meet the U.S. Department of Energy (DOE) constraints to find m [...]

by Akira Nishimura  , Satoshi Ohata  , Kaito Okukura  and Eric Hu

Received: 25 March 2020;  Published: 14 May 2020;  doi: 10.21926/jept.2002008

Biogas is a promising resource for the production of H2 since it liberates energy by recycling waste, along with the reduction of CO2. In this paper, the biogas dry reforming membrane reactor is proposed to produce H2 for use in fuel cells. Pd/Cu alloy membrane is used to enhance the performance of the biogas dry reforming reactor. This study aims at understanding the effect of operating parameters such as feed ratio of sweep gas, pressure in the reactor, and reaction temperature on the performance of the biogas dr [...]