According to International Renewable Energy Policy, the renewable energy generation capacity is accounted in total as 2,537 GW in global energy consumption by the end of 2019 [5]. The net increase of global renewable energy generation capacity is 176 GW (7.4%) in 2019. In this total renewable energy sources, solar energy continued to be a prominent energy generation that takes place as 23% approximately and 20% rise in the year 2019 compared with previous assessment year of 2018.
Table 1.1 Global industrial energy consumption pattern by fuel in 2020 and 2050 (in terms of %).
| Sources of energy | 2020 (%) | 2050 (%) |
| Liquids | 26.3 | 25.86 |
| Natural gas | 23.27 | 23.71 |
| Coal | 25.97 | 24.43 |
| Electricity | 15.77 | 16.16 |
| Renewable | 8.65 | 9.82 |
1.2 Forms of Energy
Various forms of energy [6]: Energy occurs in different forms of energy [39]. They are mechanical energy, chemical energy, electrical energy, thermal energy, nuclear energy, and radiant energy.
The various sources and output are summarized in Table 1.2 [1].
Generation of renewable energy sources—region-wise data source from renewable energy statistics 2020, comparatively renewable energy generation capacity in 2018 to 2019—is presented in Table 1.3.
There is a continuous development in an alternative energy to fossil fuels and some other energy sources in which renewable source is one of most emerging thing but it is not a new one to the world. In general, across the worldwide nations, there is larger availability of renewable energy which would meet the world’s energy demands as per requirements. However, only 0.02% of solar energy sources can be utilized of total sources like as wind energy, solar energy, bio-mass, and geothermal energy sources [7, 8]. In the past years, there is a rapid increase of solar and wind power systems, which gives a better performance characteristics and more growth rate also. The production and principal costs have been reduced suggestively of those systems. Due to these improvements in the commercial markets, renewable energy has more openings. Solar energy is more extensive technologies based on their effective outcome to the markets in various locations. According to the International Energy Outlook (IEO), total world marketed energy consumption is estimated to rise-up from the year 2020 to 2030 around 12% [7].
Table 1.2 Various sources of energy.
| Primary sources | Output energy |
| Natural Sources (Coal, Oil, Natural gas) | Electrical Energy |
| Nuclear Fuels—Uranium | Thermal Energy |
| Solar Radiation | Light Energy |
Table 1.3 Renewable energy sources, annual production, and global demand [40].
| North America | Europe | Eurasia | |||
| Capacity | 391 GW | Capacity | 573 GW | Capacity | 106 GW |
| Global | 15% | Global | 23% | Global | 4% |
| Change | + 22.3 GW | Change | + 35.3 GW | Change | + 3.1 GW |
| Growth | + 6% | Growth | + 6.6% | Growth | + 3% |
| Central America and Caribbean | Middle East | Asia | |||
| Capacity | 16 GW | Capacity | 23 GW | Capacity | 1119 GW |
| Global | 1% | Global | 1% | Global | 44% |
| Change | + 0.6 GW | Change | + 2.5 GW | Change | + 95.5 GW |
| Growth | + 4.1% | Growth | + 12.6% | Growth | + 9.3% |
| South America | Africa | Oceania | |||
| Capacity | 221 GW | Capacity | 48 GW | Capacity | 40 GW |
| Global | |||||