The document summarizes a study on compressed air energy storage (CAES) power generation systems and their performance. CAES involves using off-peak electricity to compress air for storage, then releasing the compressed air to power turbines and generate electricity during peak times. The study examines both conventional CAES systems that use natural gas and a proposed wind-CAES system that uses wind turbines to compress air for storage and power generation without fossil fuels or emissions. The wind-CAES system is identified as a more sustainable and cost-effective alternative to conventional CAES.

1. Study of Compressed Air Energy Storage Power Generation System and its Performance Supervised by Respected Prof. Dr. Abdul HameedMemon By Hafiz MudassirGulzar (Group Leader) (07ME17) Waqas Ali Tunio (Assistant Group Leader) (07ME34) Muhammad Rais (07ME16) KhalilRazaBhatti (07ME40) Ayaz Ali Soomro (07ME31) Shaikh Waqar Ahmed (07ME43) Department of Mechanical Engineering Quaid-e-Awam University of Engineering, Science & Technology, Nawabshah - Pakistan

3. Fossil Fuel Depletion (Won’t last longer)

4. Environmental Impacts & Global Warming

6. Wind Energy Benefits Renewable Resources and Technologically Viable End-uses No greenhouse gas emissions No fuel to mine, transport, or store No cooling water No Sulfur Dioxide (SO2), Nitrous Oxide (NOx), or Mercury Emissions No water pollution No wastes Insurance against conventional fossil-based price risk

8. Energy Storage Energy is stored to use it at a different time than when it was generated. Renewable energy is often intermittent (like wind and sun), and storage allows use at a convenient time. Reliable and affordable energy storage is a prerequisite for using renewable energy. Energy storage is the most promising technology currently available to meet the ever increasing demand for energy.

9. Does wind power need storage?Wind Energy is promising, but intermittent… Three contexts: Power Make wind dispatchable (price arbitrage; potential at small market share) Time Time Boost wind capacity factor at large market penetration (offsets fuel cost only) Few markets currently exist Value Market share Exploit high-quality but remote wind resources (by reducing transmission costs)

10. Importance of Energy Storage Thrust for Renewable Energy sources. Managing Grid Peaks and Outage Mitigation. Energy Buffering. Importance in the present context.

11. Types of Energy Storage Systems

13. Large capacity (> ~100 MW)Source: Schainker, 1997 (reproduced in PCAST, 1999)

14. CAES – Bottling the wind! Way to store energy generated at one time for use at another time… Compressed Air Energy Storage (CAES) refers to the compression of air to be used later as energy source. At utility scale, it can be stored during periods of low energy demand (off-peak), for use in meeting periods of higher demand (peak load). Alternatively it can be used to power tools, or even vehicles. It is a type of Mechanical Energy Storage. Preferable for large scale storage. A CAES plant stores electrical energy in the form of air pressure, then recovers this energy as an input for future power generation.

16. During the day and at peak times, air is released and heated using a small amount of natural gas.

17. When the air is released from storage, it expands through a combustion turbine to create electricity.Conceptual Representation of Conventional CAES

18. Types of CAES systems

19. Hybrid Systems In a hybrid power generation system, the stored compressed air is mixed with a fuel suitable for an internal combustion engine. For example, natural gas or biogas can be added, then combusted to heat the compressed air, and then expanded in a conventional gas turbine, using the Brayton cycle. In addition, Compressed air engines can be used in conjunction with an electric battery. The compressed air engine, drawing its energy from compressed air tanks, recharge the electric battery. Such a system is called a Pneumatic Plug-in Hybrid Electric Vehicle-system.

20. Existing hybrid systems: Future hybrid systems: A hybrid plant was commissioned in Huntorf (Germany), and again in McIntosh, Alabama (USA). Both systems use off-peak energy for the air compression. A proposed hybrid power plant is under consideration in Iowa. Here the wind power will be used for air compression. Additional facilities are under development in Norton, Ohio and Iowa Stored Energy Park (ISEP).

21. CAES Power Plant at Huntorf1st Ever – in operation since 1971

22. Lake or Ocean Storage The need for pressurized vessels or for mining can be obviated by placing the pressurized air underwater in flexible containers (e.g. plastic bags) - at the bottom of deep lakes or off sea coasts with steep drop-offs. Challenges include the limited number of suitable locations and the need for very-high-pressure pipelines between shore and depth. However, since the containers would be very inexpensive, the need for great pressure (at great depth) may not be as important. A key benefit of systems built on this concept is that charge and discharge pressures are always constant (as determined by depth).

23. Energy Storage in Submerged, Open Bottomed, Anchored Caissons This is energy storage by the displacement of water by compressed air. To recover the energy compressed air is an intermediate energy carrier. One possibility is to sink the type of caisson used. Structures could be constructed and floated into much deeper water, sunk and anchored to the bottom using rock anchors. A flexible air pipe could be brought to the surface, to say a wind turbine base, housing an air compressor and an air turbine generator set.

24. Energy Storage in Submerged, Open Bottomed, Anchored Caissons By pumping compressed air down to the caisson, water would be ejected lowering the internal water surface to the bottom of the caissons. To recover the stored energy the air valve would be opened and the energy recovered via the air turbine as the water re enters and air is forced out. Because the container is open bottomed, there is no internal or external pressure force. However there will be massive buoyancy forces to be restrained. 90% of the energy will be in the displaced water and only 10% in the compressed air itself.

25. Conventional Gas-Turbine Compressed Air Energy Storage Vs The air that drives the turbine is compressed and heated using natural gas. Nearly two-thirds of the natural gas is consumed by a typical natural gas turbine because the gas is used to drive the machine's compressor. Both compression and generation are on a single shaft and must work in unison. Needs less gas to produce power during periods of peak demand because it uses air that has already been compressed and stored underground. Uses low-cost heated compressed air to power the turbines and create off-peak electricity, conserving some natural gas. Compression and generation units are completely separated.

26. Economics of CAES CAES is the only other commercially available technology (besides pumped-hydro) able to provide the very-large system energy storage deliverability (above 100MW in single unit sizes). Since CAES facilities have no need for air compressors tied to the turbines, they can produce two to three times as much power as conventional gas turbines for the same amount of fuel.

27. CAES V Pumped Hydro Required Storage Volume to Generate 300MW (12 Hours Pumping, 12 Hours Generation) 0.28 million m3 of Compressed Air 7 million m3 of Water

28. Safety As with most technologies, compressed air has safety concerns, mainly the catastrophic rupture of the tank. Highly conservative safety codes make this a rare occurrence at the tradeoff of higher weight. Codes may limit the legal working pressure to less than 40% of the rupture pressure for steel bottles, and less than 20% for fiber-wound bottles. High pressure bottles are fairly strong so that they generally do not rupture in crashes.

29. Uses Propulsion Compressed Air Cars No roadside emissions Low cost technology Power Generation

30. Advantages Disadvantages Vs With gas prices estimated to be in the $5-6 per million BTU range in the short to medium term, an investment in underground storage could pay for itself over time. If the nation develops an energy policy that pushes renewable power sources, the idea may catch on. Wind and solar energy, for example, can be stored whenever it is generated and then released on demand—helping to negate the argument that those power sources are intermittent and therefore unreliable. Energy is lost when it is “pumped” into the cavern and then re-extracted as compressed air. Building underground storage can be expensive, which might make some prospective projects infeasible.

31. Wind-CAES – Going the unorthodox way Fabrication and Testing of CAE Power Generation System Conventional System V Proposed System

32. Wind-CAES – Going the unorthodox way Fabrication and Testing of CAE Power Generation System Conventional System V Proposed System

33. Wind-CAES – Going the unorthodox way Fabrication and Testing of CAE Power Generation System Wind Turbine Compressor Storage Tank Air Motor Generator LEDs Wind CF-CAES (Proposed system) Our Wind-CAES operates by means of wind turbine driven compressors that store energy in the form of compressed air in the reservoir. The air pressure in 8 bar inside tank. Air is extracted from the reservoir, which is used to run the air motor . Air motor drivers the Generator and produce electricity…

34. Conventional CAES Wind CF-CAES (Proposed System) Vs Fossil Fuel dependant CO2 Emissions Fossil Fuel independent No CO2 Emissions Clean and Green Energy

35. Conclusion It's a cost effective solution, developers add, because it would replace expensive “peaking” units that provide power during the hottest summer days or the coldest winter nights. Air is stored in the form of compressed air energy during off peak hours and then released during the periods of highest demand, which will also lower the prices that consumers pay for power. At the same time, compressed air energy storage units can reduce the stress on base load plants that would otherwise have to ramp up and down.

36. Recommendations - World aiming at 20-20-20 TARGET: Nobody knows the exact cost of reaching the target of 30 per cent renewable energy in 2020. But one thing is for certain: More offshore wind farms Achieving the nation’s goals of reducing dependence on fossil fuels and deploying a clean energy economy are enormous tasks that will require major technological innovation. Energy storage technologies will be major contributors in the transportation sector and will play a vital role in the electric power industry to help achieve those goals. Widespread deployment of energy storage technologies will require a three-pronged approach; Improved technologies that provide direct cost benefits to consumers and market opportunities for service providers Financial incentives such as tax credits Mandated, time-based targets for the penetration of energy storage technologies, through mechanisms such as building codes.

37. Study of Compressed Air Energy Storage Power Generation System and its Performance Supervised by Respected Prof. Dr. Abdul Hameed Memon By Hafiz Mudassir Gulzar (Group Leader) (07ME17) Waqas Ali Tunio (Assistant Group Leader) (07ME34) Muhammad Rais (07ME16) Khalil Raza Bhatti (07ME40) Ayaz Ali Soomro (07ME31) Shaikh Waqar Ahmed (07ME43) Department of Mechanical Engineering Quaid-e-Awam University of Engineering, Science & Technology, Nawabshah - Pakistan