According to the data collected in 2013, the world energy consumption was segregated into various power sources such as 31.1% from oil reserves, 28.9% from coals, 21.4% from natural gases, 10.2% from biomass and wastes, 4.8% from nuclear sources, 2.4% from hydro energy and remaining 1.2% from other renewable sources. The most common form of energy used in industrial and household purpose was oil, coal and natural gas (Lawton, 2014). These resources such as coal, oil, and natural gas are natural reserves which are depleting due to extensive extraction over time.
Coal is one of the most burned and widely available fossil fuel. Due to its large availability, it has been the core source of energy demanded worldwide. In the USA, the electricity is generated from burning coal is about 49% (Vincent & Yusuf, 2014). In terms of oil reserves as well, the price of oil has been decreasing drastically over the years. But the limited resource of this reserve will not last long as the peak has already been reached in global oil production and constant decline is overall production has been witnessed from the currently proven sources.
Nuclear energy has also been one of the modern sources of energy with uranium estimated to be around 2500 ZJ. Although this source can meet the growing demand for energy, but the increasing concerns about environmental hazards and radioactive waste created by this energy has limited its extensive production (Vincent & Yusuf, 2014). Therefore, the impact of the non-renewable resources along with the limited availability of the reserves has highlighted the issue of lack of sustainability for future generation. Renewable resources are the alternative sources of energy to protect the scarce reserve of fossil fuels.
Solar energy is one of the abundantly available energy sources from the sun's heat. The estimated solar power that falls on the surface of the Earth is around 89PW. The innovation in solar energy has developed concentrating solar power which forms heat source while the photovoltaics (PV) transforms sunlight directly into electricity via solar cells (Strbac, 2014).
The capacity of a CSP-powered plant can be within 22 to 26% without a thermal storage but can be increased to 74% along with ten hours of thermal storage (Zavody, 2014). CSP storage also enables in improving its dispatching ability rather than being partially dispatchable. Moreover, the storage will have an influential effect on enhancing the flexibility for incorporating variable energy sources.
Another source of renewable energy is hydropower. The hydropower generation provides flexibility to manage the differences in output through other sources of energy. It is usually of three types; run of river, reservoir base and pumped storage. The generation of energy can be poor due to poor flow in a river or other hydrological factors. In terms of the reservoir system, the output of energy is controllable and enhances overall flexibility. In the case of pumped storage plants, the water is pumped from low-level reservoirs to high-level storage basin and produce electricity through reverse flow during high demands. The capacity of a run of river is high but constrained by geographical and economic factors. The transmission of the energy also requires high operational cost and technological advancements. The capacity can be range between minimal Kilowatts of energy to around 20 Gigawatts (Zavody, 2014).
Wind energy is the energy generated from the wind. The electricity generated from wind power varies with the speed and power of the wind. The installment of a wind turbine, wind plant, and the area level also plays a vital role in reducing the uncertainty of output generated.
The integration of renewable energy incorporates generating renewable energy, distributing energy, storing the energy, and supplying the energy through the transmission system. The integration also develops a new model for bringing the technologies into capacity building and demand management. The benefits from the integration of renewable energy are a reduction in pollution from burning coals and oils. This helps in combining resources of the distribution system and reducing customer energy load which will ultimately decrease the cost. Through grid operation, the use of oil reserves will diminish.
However, there are several issues attached with the integration of renewable energy distributed through the transmission system.
Partial unpredictability: The energy resources such as solar energy and wind energy are partially unpredictable. As the solar power is generated through the sun or during sunny day and wind energy through the power of wind, the climatic conditions might not be consistent every time. The forecast scenarios do not always prove to be true. This uncertainty can be tackled through better prediction and forecasting technology, alternative source of energy in case of poor generation from a renewable source, and storage mechanism for storing energy during excess power.
Some examples are the windy regions in China are in far distance from the residences and load centers. Similarly even in the USA, the area with the high quality of wind lies in a dispersed location to the area where the energy is demanded.
Inflexibility: Some of the renewable sources of energy do not have the flexibility in terms of aspects of the power operation system. As they can vary with respect to time, the output cannot be predicted. Because of this, it is difficult to replace entirely the non-renewable sources as renewable sources might not be able to meet the demand.
So, the integration of different renewable energy helps in maintaining the supply level of energy rather than disrupting the operation due to poor predictability. So, the mixture of different sources must be adopted, but there are several other problems attached to it as well. The major issue also lies to make people aware regarding the importance of the transition from non-renewable sources to renewable sources. The amendments need to make in the structures, technologies as well as in the operation system.
References
Lawton, P. (2014). Integrating renewable energy: Minimising uncertainty, maximising flexibility. IET Seminar on Integrating Renewable Energy to the Grid: Optimising and Securing the Network. doi:10.1049/ic.2014.0005
Strbac, G. (2014). Facilitating cost-effective integration of renewable energy in GB grid. IET Seminar on Integrating Renewable Energy to the Grid: Optimising and Securing the Network. doi:10.1049/ic.2014.0003
Vincent, E. N., & Yusuf, S. D. (2014). Integrating Renewable Energy and Smart Grid Technology into the Nigerian Electricity Grid System. Smart Grid and Renewable Energy, 05(09), 220-238. doi:10.4236/sgre.2014.59021
Zavody, Z. (2014). The grid challenges for renewable energy: an overview and some priorities.IET Seminar on Integrating Renewable Energy to the Grid: Optimising and Securing the Network. doi:10.1049/ic.2014.0001
