Chapter Eight - Conclusion

Abstract

Today wind turbine technology has reached a point that its electricity has become cheaper than conventional energy. This is even true for locations with wind capacity factors less than 20%. However, the large-scale development of renewable energy technologies, including wind, is limited because they are intermittent. For example, for a wind turbine, if there is less wind, there will be less or even no power output. The same applies for solar-driven power plants. For making controllable frequency grids, the fluctuations of solar and wind plants must be managed. For example, agile conventional technologies such as gas turbines can come into operation or go for less production to compensate for sudden up-and-down changes in the power output of renewable power plants. The objective is to minimize and even eliminate the contribution of conventional plants as they seriously contribute to global warming. Therefore, storing the energy of renewable power plants when over-producing, and reclaiming it back to the grid when needed such as during peak consumption periods or low-production times, is vital for energy systems with high penetration of solar and wind plants. In addition, such electricity storage units give the opportunity to levelize the cost of production and electricity market spot pricing by storing electricity when the spot price is low and giving it back to the market when the spot price gets too high. This book discussed the limitations of the widely used electricity storage solutions and introduced an alternative category of solutions, mechanical energy storage (MES) technologies. Chapter 2 discussed thermal energy storage (TES) systems, Chapter 3 examined compressed air energy storage (CAES), Chapter 4 covered pumped hydropower storage (PHS), Chapter 5 discussed flywheel energy storage (FES), Chapter 6 focused on pumped heat electricity storage (PHES), and Chapter 7 examined three newly introduced systems of subcooled compressed air energy storage (SCAES), trigeneration compressed air energy storage (TCAES), and high-temperature heat and power storage (HTHPS). In this chapter, we present our final remarks and conclusions.