**8. Storage for RES**

#### **8.1 The case of grid-level storage**

It should be noted that no ES technology claims high in all aspects. Each has its own limitation in performance when used for grid connection. System capacity, type of application and the cost of peak time electricity decide the storage capacity. A wide variety of such technology may be required to address the issues arising during grid connection.

In [70] an optimized sizing methodology for battery ES to cater peak shaving and ramp rate limiting in the power dispatch using bat algorithm and validated in a grid-connected WPVHPS to combat loss of power is presented. Five types of battery ES such as lead-acid (Pb-acid), Li-ion, flow batteries and sodium sulfur (NaS) are tested in a comparative fashion. After examining storage technologies applied in four purposes such as frequency regulation, power smoothing for wind as base load plant, power smoothing for load following and peak shaving the authors [71] have arrived in a conclusion that the power accumulation capacity is vital for frequency regulation, whereas the energy capacity influences energy intensive applications like peak shaving. The transient stability of a DG-battery-super capacitor has been carried out by [72]. Korada et al. [73] have developed a three-level grid adaptive power management strategy (GA-PMS) in MG with RES—battery-supercapacitor to support grid.

A compressed air energy storage (CAES) and wind energy system is used in [74]. It is tried to time shift wind energy to maximize the daily revenue by stochastic dynamic programming (SDP) for forecasting generation and price.

With similar objective [75] has added an approximate dynamic programming (ADP) algorithm that shows the proficiency of designing near-optimal control policies for a large number of heterogeneous storage devices in a time-dependent environment with good accuracy at par with stochastic and dynamic models when demand-variability is additionally taken. The economic feasibility of a centralized CAES is more viable than the distributed wind turbines-CAES [76].

Koller et al. [77] shows the effect of the grid-connected 1 MW BESS on frequency reserves, peak clipping and islanded operation of a MG. Grid forming and grid following inverters for the variable RES is detailed in [78]. An online

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*Grid-Connected Distributed Wind-Photovoltaic Energy Management: A Review*

optimal operation [79] for BESS based on a mixed-integer-linear-program (MILP) is proposed over a rolling horizon window. After a detailed study of different batteries, Li-ion batteries of LFP-C type are suggested economical in long run for large capacities for stationary applications [80] with RES. The study on placement of storage by [81] indicates that the line-flow limits have a significant effect. Hybridizing PV-wind with micro-hydro power plants into a single mini-grid has been practically applied in Nepal [82] which has increased the reliability and meets

A study on grid-level FESS [83] showed that locating it at the transformer and higher levels in the grid will reduce its size by inherent power smoothing by the pool. The ability to exchange power with neighboring grids, load shifting and storage can deal with high penetration of renewable [84]. Peak shaving can be dealt with by gas powered generation and load leveling (flat profile) by coal-fired or

Williams et al. [86] put forth DSM by adding heat pumps and thermal storage to

A battery ES with its own specific features can serve a particular usage when time, space, portability and size are some of the factors. This section reviews battery ES in view of the latest technologies, advantages, sizing, efficiency, price, and

The modern storage technologies with regard to wind power integration are discussed in [87] on which the planning rests upon. Output power smoothing operation by single or multiple ESS considering influencing factors as above is done. In the work [88], has cross-compared with the maturity level of the technology of storage. Wide variety of storages have been detailed in [89] taking an in-depth study of the electrochemical properties of the BES. The energy capacity and the selfdischarge or capacity fade of BES systems affect the suitable storage duration. Study in [90] has shown that BES can go forward for ancillary service if its cost reduces. Palizban et al. [91] have pointed out that a hybrid of different energy storages can serve multiple purposes in a cost-effective way. In [92] the technical viability of Li-ion batteries for the inertial response (IR) in grids with ample contribution of

One particular BESS cannot suit for all the support services like short, medium as well as long term [93]. Only Li-ion can serve for short duration support. For distributed storage and medium duration support, Pb-acid and Li-ion batteries are most suitable. A lithium-antimony-lead (Li-Sb-Pb) liquid metal battery is proposed by [94] which has higher current density, longer cycle life and simpler manufactur-

RE can be better absorbed if electric vehicle charging and discharging is done strategically. Conventional power supplies can be sent as needed to match demand and provide ancillary services for grid stability. Contribution to grid by RES is increasing although these sources are intermittent by nature. This is now an operational challenge to balance the intermittency of RES. Electric vehicles (EVs) offer a scope to manage demand and potentially mitigate the amount of curtailed energy

Different types of charger such as AC/DC, slow/fast are discussed in European standard by [95]. Integration of ESSs in EVs charging station has grown with AC

*DOI: http://dx.doi.org/10.5772/intechopen.88923*

the load in an environment-friendly way.

PV that adds on energy independence of the house.

**8.2 Battery energy storage technology and materials**

battery or pump storage [85].

life cycle assessment.

wind power has been evaluated.

ing of large-scale stationary storage systems.

**8.3 Plug-in hybrid electric vehicles (PHEV)**

by controlling when EVs are charged.

### *Grid-Connected Distributed Wind-Photovoltaic Energy Management: A Review DOI: http://dx.doi.org/10.5772/intechopen.88923*

optimal operation [79] for BESS based on a mixed-integer-linear-program (MILP) is proposed over a rolling horizon window. After a detailed study of different batteries, Li-ion batteries of LFP-C type are suggested economical in long run for large capacities for stationary applications [80] with RES. The study on placement of storage by [81] indicates that the line-flow limits have a significant effect. Hybridizing PV-wind with micro-hydro power plants into a single mini-grid has been practically applied in Nepal [82] which has increased the reliability and meets the load in an environment-friendly way.

A study on grid-level FESS [83] showed that locating it at the transformer and higher levels in the grid will reduce its size by inherent power smoothing by the pool. The ability to exchange power with neighboring grids, load shifting and storage can deal with high penetration of renewable [84]. Peak shaving can be dealt with by gas powered generation and load leveling (flat profile) by coal-fired or battery or pump storage [85].

Williams et al. [86] put forth DSM by adding heat pumps and thermal storage to PV that adds on energy independence of the house.
