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 rad [...]

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 Jubert 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 [...]

by Xiang Li  , Yuan Xue  , Ryan Dehoff  , Costas Tsouris  and Patricia Taboada-Serrano

Received: 09 April 2020;  Published: 09 May 2020;  doi: 10.21926/jept.2002007

Hierarchically-structured, electro-catalysts consisting of a titanium core with controlled macro-porosity and a thin titania surface-layer with controlled nano-porosity were synthesized via combination of additive manufacturing and in-situ anodization. The electrodes were tested for hydrogen evolution reaction and depicted competitive electro-catalytic activities, with Tafel slopes between 40 and 56 mV dec-1. The electrodes also depicted competitive onset and over potentials when compared with other electrode alter [...]

by Megan Schutt  and Harvey Seim

Received: 10 April 2020;  Published: 30 April 2020;  doi: 10.21926/jept.2002006

SODAR wind profiler measurements from a land-based site within 1000 m of the coastal ocean are compared with predicted wind profiles based on upwind conditions and a stability-based model. The thermally dynamic influence of the Gulf Stream near the site of measurement, Cape Hatteras, has been found to complicate wind speed estimation at height through its impacts on atmospheric stability and the resulting changes to wind shear. The COARE 3.0 algorithm was used to calculate a Monin-Obukhov Similarity Theory (MOST) s [...]

by Max F. Platzer  and Nesrin Sarigul-Klijn

Received: 28 January 2020;  Published: 29 April 2020;  doi: 10.21926/jept.2002005

The current status of a project is described which aims to demonstrate the technical and economic feasibility of converting the vast wind energy available over the globe’s oceans and lakes into storable energy. To this end, autonomous high-performance sailing ships are equipped with hydrokinetic turbines whose output is stored either in electric batteries or is fed into electrolysers to produce hydrogen which then is compressed and stored in tanks. In the present paper, the previous analytical studies which showed [...]