Dear Colleagues,

This Special Issue is focused on recent advancements in a series of related domains.

The increasing usage of solar energy and the integration of photovoltaic power plants into the grid demands accurate knowledge and forecasting of solar energy resources. Moreover, the performance of solar thermal power converter and photovoltaic systems essentially depends on the incidence of the beam solar flux on the solar collector surface.

Accounts of studies suitable for this Special Issue could be focused on increasing the quality of modeling and assessing the solar potential under clear sky, with the aim of contributing to the increased accuracy in estimating solar energy production.

The aim of this Special Issue encompasses the ability of parametric clear-sky solar irradiance models to both estimate and accurately separate global horizontal solar irradiance into its fundamental components of beam and diffuse, increasing the accuracy of solar energy production estimation by developing clear-sky solar irradiance models tuned for properly capturing the effect of aerosols at a high concentration in the atmosphere but, also, the thermal degradation of photovoltaic (PV) cells in time. The aim of this issue is to explore a range of testing methods for such a monitoring, including scanning electron microscopy (SEM), atomic force microscopy (AFM), and nondestructive testing (NDT) involving optical coherence tomography (OCT) and hardness measurements.

Thermal processes, i.e., pyrolysis, combustion, and gasification, appear to be suitable for converting biomass into an energy source. It is therefore of relevance to address such issues such as anaerobic digestion (AD), which is one of the means by which agricultural substrates can be converted in biogas which, in turn, can be used as fuel for firing processes with influence on obtaining clean energy. The biogas and digestate are of equal importance in energy production, and they also significantly contribute to systemic greenhouse gas (GHG) mitigation by recycling household and agricultural waste. Further improvements can be obtained in both energy production and emissions mitigation when the ratio of the three biogas utilization pathways (heating, illumination, and fuel) is adjusted.

The topics of interest include the development of related methods and devices (with analytical approaches, simulations, and/or experiments), their optimization, and their inclusion in dedicated systems for applications.

The forum is open to all researchers in the abovementioned fields. All types of contributions, e.g., research papers, reviews, and communications, are welcome.

Prof. Dr. Nicolina Pop
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Energies is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

• solar energy
• solar radiation
• thermal energy storage
• thermal degradation
• photovoltaic cell
• biogas
• optical coherence tomography (OCT)
• analytic approaches
• numerical simulations