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Solar–wind hybrid renewable energy system 241

In their work, Jonathan et al. [119] presented a control technology for HRES that
track and make control decisions depending on the definite battery state of charge
(SOC). This method offers significant advantages over other methods. In another
study, Ottoson et al. [120] used a data logger and gave a comprehensive analysis of
the energy production and performance of an HRES comprising solar, wind and diesel
plant. Nogaret et al. [121] presented an expert system based control mechanism for
HRES. This technique uses an advanced control system for the optimal operation and
supervision of solar and wind based medium size HRES. Chedid et al. used CAD
(Computer aided design) tool [122] for optimally design and control a hybrid wind
solar power systems considering all environmental factors. Studies have been reported
in the literature using Linear programming techniques to reduce the production cost
while meeting the load requirement. Researchers Pitrone and Pitrone [123] used an
expert system incorporating fuzzy logic theory, neural network and programmable
logical controller (PLC) for on line supervision and control of distributed HRES.

6 Conclusion

The application of solar–wind HRES is increasing day by day and has shown incred-
ible growth in last few decades for producing electricity all over the world. New tech-
nologies are being introduced in the field of solar wind HRES, that in terms introduce
new problems which inspire the researchers to solve them. Hence, with the advance-
ment of the techniques in the field of HRES, there is a huge scope of further work.
This chapter has presented the progress of these technologies, which includes the
feasibility study, modelling of the system components, optimal sizing and control
technologies of the HRES. Most of the commonly used technologies to evaluate the
system power reliability and system cost is investigated and reported in this chapter.
Numerous optimization techniques including the graphic construction methods, prob-
abilistic approach, iterative technique, multi-objective design etc. have been reviewed
and presented.
From the literature review presented in this chapter, it can be observed that HRES
is increasingly popular as an alternative to conventional sources in the process of elec-
trical power generation. Almost in all reviewed systems that include more than one
alternative and/or conventional energy sources, like diesel generator or conventional
grid, it can be noticed that they present better performance than systems which only
include one alternative energy source. The current trend in the development of multi-
objective sizing methodologies can be observed to make the HRES reliable, feasible,
and environmentally friendly.
It is clear from the study that a detailed renewable energy resource analysis at first
stage of the design is essential for optimum sizing of a hybrid solar–wind HRES. Also,
optimum resource distribution based on load demand is essential to reduce estab-
lishment cost and operation cost. The integration of the different types of renewable
energy sources with storage devices that is battery improves the reliability and per-
formance of the system. The inclusion of artificial intelligence as part of the energy
management system can help operators reduce the system’s cost in the future.