Introductory Chapter: Overview of Renewable Energy

1. Introduction

This chapter presents an introductory review about renewable energies. Renewable energy is the most important resource of reproducible infinite energy [1]. There are major differences between renewable and regular energy resources. These differences include the diversity, availability, and potential everywhere. Moreover, renewable energy produces less carbon dioxide [2, 3, 4]. Renewable energy has several forms. These forms include solar, water, wind, geothermal, and biomass. Wind energy is produced from air and wind. It is produced due to the heat of the Earth’s surface. The more the wind speed increases, the more energy is produced. On the other hand, the solar energy is produced from the sunlight. Special silicon cells are used to collect sunlight. The resulting collected energy is stored on batteries. Several types of batteries are used for storing solar energy. Biomass energy is another form of renewable energy. This type of energy is produced from biomaterials. Geothermal energy is produced from heat inside the earth [5, 6].

2. Renewable energy technologies

There are several technologies used for producing the renewable energy. These technologies include electrical and mechanical to produce heat and electricity. These technologies are used for hydro, solar, fuels, and geothermal energy [7]. Renewable energy resources are divided into several categories. These categories differ from country to country and from land to land. Different countries have different policies for the renewable energy categories. The political perspective of the policy maker in one country may be to justify different treatment for established resources such as large hydroelectric from nascent resources such as geothermal [8].

3. Different types of renewable energy sources

There are several types of renewable energy sources including:

1. Geothermal resources. This type of energy requires drilling in the ground to be extracted. Drilling is very expensive and requires a lot of time.

2. Hydroelectric resources. This type of energy is extracted from the seashore and water resources. It mainly depends on the water movements.

3. Wind energy. Wind energy depends on the wind speed and direction. It is constructed on the shores, mountains, and flat areas.

4. Solar energy. This type of energy is extracted from the sun. Some countries like Saudi Arabia, UEA, and other Arab countries are very suitable for the solar energy.

5. Biomass energy. This type of energy is extracted from wood and waste, agricultural waste and residue, and crops. The cost of this type of energy is very high.

4. Renewable energy applications

Renewable energy has several applications. These applications can be divided based on two categories: ON Grid and the OFF Grid. The ON Grid includes solar and wind energy [8, 9]. The OFF Grid includes biomass and geothermal energies. The most important factor for these two categories is the cost of connections and installations. The OFF Grid is used for homes and small businesses. On the other hand, ON Grid is used for cities and big factories. Moreover, a third category, mini Grid, is used for mixed applications [9].

5. Benefits of renewable energy

The advantages of renewable energy are numerous and affect the economy, environment, national security, and human health. Some benefits include reliability, security, and resilience of power grid, job creation industries, and reduced carbon emissions and air pollution [9, 10, 11].