Techno-Economic Analysis of Small Size Second Generation CAES System☆

Abstract Among the presently available energy storage systems, second generation CAES 2 (Compressed Air Energy Storage) shows attractive economic and operational features together with satisfactory level of performance.CAES2 plants integrate an air compression and storage system with a commercially available Gas Turbine. A small size plants based on a 4600 kW Mercury recuperated Gas Turbine equipped with an artificial compressed air storage system has been investigated. Preliminary evaluations have been carried out to assess the maximum achievable GT power augmentation taking operations safety and plant life duration into consideration. For a fixed amount of stored air (defined according to the requested minimum duration of the discharge phase), investment, maintenance and operating costs have been evaluated by varying the air storage pressure from 2000 to 10000 kPa. The minimum annual equivalent cost is achieved by assuming a design storage pressure of 4000 kPa. From 4000 to 10000 kPa, costs are in practice insensitive to the air storage pressure

Analysis of diabatic compressed air energy storage systems with artificial reservoir using the levelized cost of storage method

A detailed analysis has been carried out to assess the thermodynamic and economic performance of Diabatic Compressed Air Energy Storage (D-CAES) systems equipped with above-ground artificial storage. D-CAES plant arrangements based on both Steam Turbine (ST) and Gas Turbine (GT) technologies are taken into consideration. The influence of key design quantities (ie, storage pressure, turbine inlet pressure, turbine inlet temperature) on efficiency, capital and operating costs is analysed in detail and widely discussed. Finally, D-CAES design solutions are compared with Battery Energy Storage (BES) systems on the basis of the Levelized Cost of Storage (LCOS) method. Results show that the adoption of D-CAES can lead to better economic performance with respect to mature and emerging BES technologies. D-CAES ST based solutions can achieve a LCOS of 28 €cent/kWh, really close to that evaluated for the better performing BES system. Interesting LCOS values of 20 €cent/kWh have been attained by adopting D-CAES plant solutions based on GT technology

Techno-economic analysis of a sCO2 power plant for waste heat recovery in steel industry

Abstract Industrial facilities release a large amount of heat as a by-product of their processes. To improve environmental performance and increase process profitability, a portion of the waste heat can be recovered and employed for power generation by recovery systems. Supercritical carbon dioxide (sCO2) plants are emerging as potential alternatives to the well-established technologies for waste heat recovery (WHR) power generation in heavy industry. This paper offers a preliminary techno-economic analysis of a waste heat-to-power system based on a sCO2 closed-loop for a heavy-industrial process. By conducting a parametric investigation on the WHR sCO2 system's key design parameters, a number of preferable configurations from a thermodynamic perspective were initially identified; they were subsequently analyzed from the economic point of view in terms of net present value (NPV) and pay-back period (PBP). The privileged WHR system configuration achieved an overall efficiency of 30.4% and a power output of 21.6 kWe, providing an NPV of almost US k$ 376 with a PBP of approximately 4.5 years

Design of power-blocks for medium-scale supercritical carbon dioxide plants

For power production, the emerging technologies of supercritical carbon dioxide (S-CO2) cycles show potential advantages if compared to conventional plants. The current bottleneck in exploiting such cycles is the development of novel components such as turbomachines and heat-exchangers. This paper focuses on the layout arrangement and machinery design of a novel power block for a 10 to 15 MW supercritical carbon dioxide plant. The applied design procedure involves 0D and 1D models implemented using an in-house Fortran code, and 3D computational fluid dynamics (CFD) analyses using ANSYS-CFX. Novel configurations of the power block were designed, starting with the same primary thermal source. At nominal conditions, expected overall output powers from 13.2 to 16.2 MW were found. Finally, some qualitative considerations were included in the discussion to compare the analysed arrangements

Performance assessment of a CAES system integrated into a gas-steam combined plant

In the present paper, the performance of an energy storage concept based on the integration of a Compressed Air Energy Storage (CAES) system into a Gas Steam Combined Cycle (GSCC) plant is investigated. CAES systems featured by different design power output have been coupled with a commercially available small size GSCC plant. Storage efficiencies around 63% have been evaluated for CAES design power output ranging from 5 to 10 MW. Such encouraging values, together with other CAES good features (long life duration and established technologies available for key plant components) confirm the potential of the proposed system to emerge as an economically viable energy storage alternative

CAES systems integrated into a gas-steam combined plant: Design point performance assessment

In the present paper, the performance of an energy storage concept based on the integration of a compressed air energy storage (CAES) system into a gas-steam combined cycle (GSCC) plant is investigated. CAES systems featured by different design specifications have been coupled with a commercially available small size GSCC plant. Storage efficiencies up to 65% have been evaluated for CAES design power output ranging from 5 to 10 MW. A techno-economic analysis aimed at assessing plant performance and investment costs has been performed. Despite the relatively high investment costs and the storage efficiency being less than those featuring alternative storage approaches, the proposed system may be considered of interest due to the long-life duration and the established technologies available for the key plant components

Performance Analysis of Small Size Compressed Air Energy Storage Systems for Power Augmentation: Air Injection and Air Injection/Expander Schemes

Two small size second-generation compressed air energy storage (CAES) systems have been investigated. Both plants are based on a 4600 kW Mercury recuperated gas turbine (GT) and on an artificial air storage system. In CAES air injection (CAES AI) plant, the stored compressed air is mixed with the air flow exiting the GT compressor and fed after a recuperative heating to the GT combustion chamber. A topping air expander is included in the CAES air injection/expander (CAES AI/E) plant scheme. Preliminary evaluations have been carried out to assess the maximum achievable GT power augmentation taking safety of operations and plant life duration into consideration. Plant performance has been evaluated during the overall operational cycle (charging, storage and discharging phases). CAES AI plant allows a 30% maximum extra power delivery (some 1500 kW) in respect to the nominal design GT power. The introduction of the topping air expander in CAES AI/E plant allows an additional power production of some 300 kW. Both plants have shown storage efficiency improvements by reducing the discharge period duration. Satisfactory values around 70% have been found in the best operating conditions

Techno-Economic Analysis of CAES Systems Integrated into Gas-Steam Combined Plants

In the present paper, an energy storage concept based on the integration of a Compressed Air Energy Storage system into a Gas Steam Combined Cycle plants is investigated. The integration of CAES results in a noticeable power augmentation in respect to normal GSCC plant operations. Being such a power increase obtained without using additional fuel, the storage system can be compared to PHS, BES and A-CAES. Two CAES integrated into medium size GSCC plants arranged with Aero Derivative and Heavy Duty Gas Turbines have been investigated. A techno economic analysis aimed at assessing plant performance and investment costs has been performed. Despite the relatively high investment costs and the storage efficiency lesser than those featuring alternative storage approaches, the proposed system may be considered of interest due to the long life duration and the established technologies available for the key plant components

PERFORMANCE ANALYSIS OF SMALL SIZE CAES SYSTEMS

Two small size second generation CAES systems have been investigated. Both plant are based on a 4600 kW Mercury recuperated Gas Turbine and on an artificial air storage system. In CAES AI plant, the stored compressed air is mixed with the air flow exiting the GT compressor and fed after a recuperative heating to the GT combustion chamber. A topping air expander is included in the CAES AI/E plant scheme. Preliminary evaluations have been carried out to assess the maximum achievable GT power augmentation taking safety of operations and plant life duration into consideration. Plant performance has been evaluated during the overall operational cycle (charging, storage and discharging phases). CAES AI plant allows a 30% maximum extra power delivery (some 1500 kW) in respect to the nominal design GT power. The introduction of the topping air expander in CAES AI/E plant allows an additional power production of some 300 kW. Both plants have shown storage efficiency improvements by reducing the discharge period duration. Satisfactory values around 70% have been found in the best operating conditions