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

Introduction

Today, energy is one of the basic human needs, and human dependence on fossil fuels is much higher than in the past, as more than 90% of the world's energy consumption comes from fossil fuels.\cite{Healy_2017}\cite{2020}\cite{Bos_2017} Energy considers one of the most important factors of production and its optimal use is one of the effective factors in the growth and development of countries. \cite{a2016}\cite{Giddey_2019}\cite{a2020}\cite{Kova__2019}[4,5,6,7] In this regard, the supply of energy required by human societies and concerns about the continuity of its supply is of particular importance. The development and expansion of renewable energy help to achieve the goals of economic, social and environmental development of the country, which are key factors in achieving sustainable development in any country. [8,9,10] The use of new energy, such as nuclear, solar, wind, etc., can reduce dependence on fossil fuels, reduce the emission of polluting gases from the manufacturing and energy sectors, and reduce greenhouse gas emissions.[11,12,13] The world's extreme dependence and growing need for energy resources, which is a key factor in the growth and economic activity, on the one hand, and the limitations of oil reserves and other fossil fuels, on the other, have made the world more energy-intensive in recent years. The potential problem of climate change and its relationship to fossil fuel consumption and rising greenhouse gases has also contributed to the global problem. [14,15] Although fossil fuels, especially oil, still play a key role in supplying the world's energy needs, the crisis of the 1970s has for the first time exposed the vulnerability of its supply security to industrialized nations. Therefore, according to the above, the exploitation of renewable energy is inevitable. [16,17]
Vaziri rad et al [18] Rural electrification challenges in Iran are the most important obstacle to achieve electricity access for the entire population. The current study focuses on finding an optimal renewable energy system to meet the load of a small village by renewable resources. This village faces frequent power outages, common in many far-off villages in Iran. 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 fuel cell to this configuration would increase costs by 33–37%, but also improve system flexibility. Using a reformer is more efficient and about 6% less costly, but also 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. [19] studied Design of hybrid power systems using HOMER simulator for different renewable energy sources. Buonomano et al. [20] selected a hybrid renewable system based on wind and solar energy coupled with an electrical storage: Dynamic simulation and economic assessment. Zhang et al. [21] studied Optimization with a simulated annealing algorithm of a hybrid system for renewable energy including battery and hydrogen storage. Budak et al. [22] studied Comparative study of PV/PEM fuel cell hybrid energy system based on methanol and water electrolysis Mohammed et al. [23] Optimal design and energy management of a hybrid power generation system based on wind/tidal/Pv sources: Case study for the Ouessant French island. In another study [24], it was found that optimization and evaluation of a wind, solar and fuel cell hybrid system in supplying electricity to a remote district in national grid. Gökçek et al. [25] performed Techno-economical evaluation of a hydrogen refuelling station powered by Wind-PV hybrid power system: A case study for İzmir-Çeşme. Other research has been done to optimize renewable energy for the lowest cost [26,27,28,29].
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 energies 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 preparing the potential for renewables, one must take care how and on what the information is based. The potential of renewable in an area is usually estimated based on the atlas provided for that energy in the area. If the Atlas is 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 area renewable (wind speed, sunlight intensity, etc.) needed in software computing. Furthermore, the geographical and climatic characteristics of the area must be precisely determined as well. The point to be noted about the potential of renewable in a region is that the calculations have to be based on a varied, geographic and geographic approach to be valid. It is better to have complete data on renewable energy sources based on field studies for at least one year. Thus, in discussing the potential assessment of renewable energy sources, the following are needed:
• The potential relevance of renewable resources in an area and its effective role in the selection of renewable energy systems
• Variability of the potential renewable energy sources in the area
• The priority of raw and unprocessed data on renewable energy sources
In all of the studies done before the potential assessment has been carried out and evaluated, this study performed, the potential assessment first and then the use of renewable energies.