Keywords: fossil fuel resources, renewable energy, investment cost, hydrogen storage.

Introduction

Dependence on fossil fuels is higher than ever before, as more than 90% of the world's energy consumption comes from fossil fuels \cite{Healy_2017,f2020,Bos_2017}. Optimal production and use of energy are key factors in the growth and development of countries \cite{a2016,Giddey_2019,a2020,Kova__2019}. Of particular importance are the quality and reliability of supply. The development and expansion of renewable energy are beneficial for economic, social and environmental development, which are key factors in achieving sustainable development in any country \cite{Alayi_2019,Hadidian_Moghaddam_2019,Ayodele_2019}. The use of new energy technologies, such as nuclear, solar and wind, can reduce dependence on fossil fuels, reduce emissions of polluting gases from the manufacturing and energy sectors and of greenhouse gases \cite{Alayi_2019a,r2015,Zhang_2019}.  Concerns about climate change and its relationship to fossil fuel consumption and rising greenhouse gases have given the problem a higher global profile\cite{a2020a,Baykara_2018}. The crises of the 1970s underlined the vulnerability of industrialized nations as regards oil supply security, bolstering the case for renewable energy technologies \cite{Abdin_2019,Uyar_2017}
According to Vaziri Rad et al. \cite{Rad_2020} rural electrification is a key challenge in achieving access to electricity for the entire population of Iran. The current study focuses on finding an optimal renewable energy system to meet the load of a small village. This village faces frequent power outages, a common occurrence in remote villages around the world. A hybrid photovoltaics/wind turbine/biogas generator/fuel cell renewable energy system is proposed and analyzed for both stand-alone and on-grid application. Fuel cells are used alongside a hydrogen tank, batteries, and a reformer or an electrolyzer, to act as storage devices and backup component. The main goal is to find an optimal configuration that can meet the electricity demand and be satisfactory from both an economic and environmental point of view. The results indicated that using solar, wind and biogas is the most affordable method and that adding a fuel cell to this configuration would increase costs by 33–37%, but would also improve system flexibility. Using a reformer is more efficient and about 6% less costly, but creates more pollution. The cost of energy for a stand-alone system with reformer was calculated to be 0.164 to 0.233 $/kWh, while the on-grid system cost of energy was 0.096–0.125 $/kWh. Cristian et al.  \cite{Cristian_2017}  studied the design of hybrid power systems using the HOMER simulator for different renewable energy sources. Buonomano et al.  \cite{Buonomano_2018}  selected a hybrid renewable system based on wind and solar energy coupled with electrical storage: dynamic simulation and economic assessment. Zhang et al.  \cite{Zhang_2018} studied optimization with a simulated annealing algorithm of a hybrid system for renewable energy including battery and hydrogen storage. Budak et al. \cite{Budak_2019} made a comparative study of PV/PEM fuel cell hybrid energy system based on methanol and water electrolysis. Mohammed et al. \cite{Mohammed_2017} studied optimal design and energy management of a hybrid power generation system based on wind/tidal/Pv sources: Case study for the French island of Ouessant . Another study \cite{Alayi_2019b} looked at optimization and evaluation of a wind, solar and fuel cell hybrid system supplying electricity to a remote district on the national grid. Gökçek et al. \cite{G_k_ek_2018} performed a techno-economical evaluation of a hydrogen refuelling station powered by a wind-PV hybrid power system, in a case study for İzmir-Çeşme. Other research has been done to optimize renewable energy at the lowest cost \cite{Anoune_2018,Sanajaoba_Singh_2018,Duman_2018,Bayrak_2016}.
Potentiometric means extracting the values of each of the renewable energies and then selecting one or more sources of potential energy from the available resources. As selecting the right type of renewable energy in an area calls for careful estimation of the potential of renewable energies in that area, knowing the potential of each type of renewable energies in an area contributes to the decision on the type of primary system applicable in an area. In determining the potential for renewables, great care must be taken as regards the base information on which the analysis is based and how it is used. The potential of a particular renewable in an area is usually estimated based on the atlas provided for that energy in the locality. If atlas data are not available, field studies will be necessary to estimate the potential of the region's renewable resources, because in the initial design of renewable systems what is important is accurate hour-to-hour information on the renewable potential (wind speed, sunlight intensity, etc.). Furthermore, the geographical and climatic characteristics of the area must be precisely determined. The point to be noted about the potential of renewables in a region is that,  to be valid, the calculations have to be based on a varied geographic approach . It is preferable to have complete data on renewable energy sources based on field studies for at least a one year period. Thus, when assessing renewable energy sources for possible use in a locality, the following are needed:
In this study, the potential assessment was performed first, followed by an assessment of the renewable energies.