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Energy storage technologies


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This presentation outlines the different storage technology options available to cope up with the intermittent nature of the Renewable energy like wind and solar.

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Energy storage technologies

  1. 1. Energy Storage Technologies In Renewable Energy Energy storage technologies 1
  2. 2. Need of Energy Storage In renewable Energy The energy storage along with renewable energy generators/PV is required to increase the reliability and flexibility. The intermittent nature of renewable sources like solar and wind needs storage to deliver the right amount of power at right quality. To accommodate the projected high penetration of solar and wind energy in future grids with lower grid rejection loss. Energy storage technologies 2
  3. 3. Services of Energy storage technologies  Energy Arbitrate: Storing cheap off-peak energy and dispatching it as peak electricity which requires large storage reservoir required at large capacity. o Examples: Compressed air and pumped hydro  Load Regulation:  Responding to small changes in demand  Energy Storage technologies were suitable for load/frequency regulation due to their high response time and high partial load efficiency.  They have to be Highly reliable Continuous change in output power Suitable for frequent on-off Examples: Flywheel, Ultra capacitors, Batteries Energy storage technologies 3
  4. 4. Services of Energy storage technologies(cntd.) Contingency Reserves: Mainly used as alternatives for generators when there is transmission line trip or grid failure. These are categorised into three types: – Spinning reserve: operates with in 10 min of outage – Supplemental reserve: Comes into operation when spinning reserve is fully discharged. – Back up reserve: Acts as a back up in case of spinning/supplemental reserve failure. In all the services the load regulation service yields more revenue but each storage technology can participate in more than one market. Energy storage technologies 4
  5. 5. Other services of Energy storage:  Load following: To fill the difference or gap between demand and supply. – Difference between load following and load regulation is the time scale. – The range for load regulation is a few seconds. – The range for load following is with in minutes.  Capacity supply: The capacity supply reduces the investment for new thermal or other conventional generation technologies. The investor could rent the storage capacity in the market.  Transmission and distribution loss reduction: With the rise in demand new transmission lines has to be set up which increases capital cost and the transmission losses. Energy storage at the load centres resolves both of the problems. Energy storage technologies 5
  6. 6. Energy storage technologies-Categories  Power quality: Main purpose is frequency and voltage regulation.  Operating range: Seconds to few minutes  Examples: Flywheel, Ultra capacitors, SMES, Batteries  Bridging power: Main purpose is to act as contingency reserves and ramping of load.  Operating range: Few minutes to one/two hour  Examples: High energy density batteries.  Energy Management: The main purpose is load following, Capacity supply, Reduction of transmission and distribution losses.  Operating range: Few hours to days  Examples: CAES, pumped hydro storage 6 Energy storage technologies
  7. 7. Overview  Technology Types– Batteries, flywheels, electrochemical capacitors, SMES, Pumped hydro, Compressed air energy storage.  Theory of Operation– Brief description of the technologies and the differences between them  State-of-the-art– Past demonstrations, existing hurdles and performance targets for commercialization  Cost and cost projections:– Prototype cost vs. fully commercialized targets Energy storage technologies 7
  8. 8. Technology Choice for Discharge Time and Power Rating Energy storage technologies 8
  9. 9. Available Energy storage Technologies and Maturity levels       Batteries SMES Flywheels Electrochemical Ultra Capacitors Conventional pumped hydro Compressed air Energy storage technologies 9
  10. 10. Batteries  Batteries store energy chemically and uses electrochemical reactions to produce electricity at a fixed voltage  Pros: – Convenient voltage Characteristics – Convenient sizing – Extensive design history  Cons: – Limited cycle life – Voltage and current limitations, requiring complex series/parallel systems – Often present environmental hazard  Battery Application Suitability – Batteries are suitable for applications that require the supply of relatively large amounts of energy storage (>1 MWh) over long periods of time (15 minutes or more), where rapid recharge is not necessary and where maintenance can be reasonably performed. – They are not especially suitable for environmentally sensitive sites, remote locations, or applications that require rapid discharge and absorption of energy. Energy storage technologies 10
  11. 11. Cycle life Energy storage technologies 11
  12. 12. Flywheel     Flywheels store energy in the form of momentum in a rotating wheel or cylinder. Principle: An electric motor spins the rotor to a high velocity to charge the flywheel. During discharge, the motor acts as a generator, converting the rotational energy into electricity.  Power electronics are used to ensure that output voltage has appropriate voltage and frequency characteristics  Pros: – High power density – High cycle life – Quick recharge Independent – power and Energy sizing  – – – Cons: Low energy density Large standby losses Potentially dangerous failure modes Energy storage technologies 12
  13. 13. Electro chemical/Super/Ultra capacitors  Electrochemical capacitors (EC), also known as super capacitors, ultra capacitors, or electrical double-layer capacitors (EDLC), store energy in the electrical double layer at an electrode/electrolyte interface.  Pros: • High power density • High cycle life • Quick recharge  Cons: • Low energy density • Expensive • Sloped voltage curve requires power electronics • Energy and Power Density of Electrical Super capacitors: • The energy and power densities of electrochemical capacitors fall between those of batteries and conventional capacitors. Energy storage technologies 13
  14. 14. Electrochemical Capacitor Technology Status  Currently viable for bridging power (seconds) in the hundreds of kW power range.  Smaller (several kW) power range, long term energy storage (hours) application of electrochemical capacitors for residential peak shaving is another application that is currently under consideration.  Use of ECs for multi-MW utility T&D applications that require several hours of energy storage (peak shaving, load levelling, etc.) is not feasible at present. Energy storage technologies 14
  15. 15. Superconducting Magnetic Energy storage(SMES)  SMES systems store energy in the magnetic field produced by current flowing through a superconducting coil.  The SMES energy-storage principle is based on inductive energy storage in the magnetic field produced by current flowing through a superconducting coil.  The DC current is converted to three-phase AC output using a solid-state power-conditioning system.  Pros: – High Power – Quick recharge  Cons: – Low energy density – Large parasitic losses – Expensive  SMES Technology Status – Currently viable for short-term power (seconds) in the 1-10 MW power range – Proposed applications are in PQ and transmission support – Several demonstration projects have shown the capability of the technology in these applications. – High initial cost is the major obstacle for the technology Energy storage technologies 15
  16. 16. Compressed Air Energy Storage (CAES)  Air is compressed and stored in large underground spaces, and is later used in gas turbine generators.  Smaller Hybrid Systems (<50 MW)  Above Ground  Pros: – Huge energy and power capacity  Cons: – Requires special location – Expensive to build and maintain – Slow start –an unlikely candidate for distributed resources. Energy storage technologies 16
  17. 17. Pumped Hydroelectric Storage  Water is pumped from low elevations to higher elevations to store energy as gravitational energy, and run down through hydroelectric turbines to generate electricity.  Pros: – Huge energy and power capacity  Cons: – Requires special locations – Expensive to build – Not suitable for DER Energy storage technologies 17
  18. 18. Technology Comparison Energy storage technologies 18
  19. 19. Proposed Models Energy storage technologies 19
  20. 20. Heterogeneous Energy Storage System(HESS)  Since all the storage technologies have their own merits and demerits a composite system has to be designed to enjoy all the storages to maximum possible efficient way.  The proposed model contains heterogeneous storage systems each of which includes several units of homogenous units.  The charge allocated for each type of storage system is decided instantaneously depending upon the load requirements.  Each type of storage bank is connected to the common charge transfer interface through a converter whose output current(charging current) is regulated to achieve the maximum possible efficiency of whole system. Energy storage technologies 20
  21. 21. Energy storage technologies 21
  22. 22. Distributed Micro-Energy storage • Distributed Battery Micro-Storage Systems Design and Operation in a Deregulated Electricity Market • The deregulation of electricity market is evident from the entry of renewable Energy so the distributed energy storage or micro storage which is not the storage at the grid level but at the lower/load level. • The off peak energy is been stored and it is dispatched at the peak hours to shave the peak demand and power regulations. • The paper suggests the hardware design considering the DOD and health of the battery and static, dynamic economic model to maximise the return keeping the battery conditions in mind. Energy storage technologies 22
  23. 23. Flowchart of the day-ahead operation scheduling of the MSS Energy storage technologies 23
  24. 24. Li-Ion Battery-Super capacitor Hybrid Storage System • The energy storage has to address the two types of discharge/charging i.e faster rates of discharging/charging for short time periods for ramping up the load or regulating the voltage, frequency etc. and discharging/charging at slower rates for long hours for load following. • But if the batteries were discharged at rapid rates the life time will gets reduced drastically. So there has to be an integration of storage devices to cope up with the charging and discharging conditions. • This paper describes the integration of super capacitors which suits the faster charging and discharging and the Li-ion batteries which charges and discharges slowly thus giving the power output for long time. Energy storage technologies 24
  25. 25. Power management block diagram Energy storage technologies 25
  26. 26. Optimal Charging/Discharging Scheduling of BSS  Traditionally, the BSSs are charged and discharged in off-peak load and peak load hours, respectively.  However, to cope with the intermittent output of PVGSs, the charging/discharging scheduling of BSSs should be arranged at least hourly with respect to the load variations and intermittent outputs of PVGSs. Energy storage technologies 26
  27. 27. Charging and discharging limits Proposed piecewise CC charging for CV stage. Energy storage technologies 27
  28. 28. Thank you Energy storage technologies 28