Grid scale energy storage systems using reheated air turbine or gas turbine expanders
Electrical power systems, including generating capacity of a gas turbine, where additional power is generated from an air expander and gas turbine simultaneously from a stored compressed air and thermal system.
1. A method of operating a compressed air energy storage system associated with a gas turbine power plant, the compressed air energy storage system having an air storage tank in fluid communication with a multi-stage compressor and a multi-stage air expander, the multi-stage compressor comprising a low pressure compressor having an intercooler associated therewith and a high pressure compressor, the method comprising:
operating the compressed air energy storage system in an energy storage mode by:
compressing ambient air in the low pressure compressor, cooling the compressed air using the intercooler, and then compressing the compressed air in the high pressure compressor to generate a first compressed air flow; and
directing the first compressed air flow from the high pressure compressor directly to the air storage tank; and,
operating the compressed air energy storage system in an air injection mode by:
compressing ambient air in the low pressure compressor to generate a second compressed air flow, the second compressed air flow bypassing each of the intercooler and the high pressure compressor;
directing the first compressed air flow from the storage tank, through a first heater and into the multi-stage air expander;
mixing the first compressed air flow downstream of the multi-stage air expander with the second compressed air flow to form an injection air flow; and
injecting the injection air flow into a gas turbine;
wherein, a pressure of the second compressed air flow exiting the low pressure compressor is greater than a pressure of air in a compressor discharge plenum of the gas turbine.
2. The method of claim 1 further comprising directing the infection air flow to the compressor discharge plenum of the gas turbine.
3. The method of claim 1 further comprising directing the first compressed air flow through a heater prior to each subsequent stage of the multi-stage air expander.
4. The method of claim 1 further comprising providing a second heater immediately downstream of the first heater.
5. The method of claim 1 further comprising applying hydraulic pressure to the air storage tank as air exits the air storage tank.
6. The method of claim 5 , wherein a pump directs a flow of water from a water tank to the air storage tank thereby applying the hydraulic pressure.
7. The method of claim 1 , wherein at least the first heater includes a thermal storage medium.
8. The method of claim 1 , wherein the first heater is a graphite-based heater.
9. The method of claim 1 , wherein the first heater is a thermal storage heater or a fueled air heater.
10. The method of claim 1 , further comprising heating the second compressed air flow with a second heater located between the gas turbine engine and the low pressure compressor.
11. A method of operating a compressed air energy storage system associated with a gas turbine, the compressed air energy storage system having an air storage tank in fluid communication with a multi-stage compressor and an expander, the multi-stage compressor comprising a low pressure compressor having an intercooler associated therewith and a high pressure compressor, the method comprising:
operating the compressed air energy storage system in an energy storage mode by:
compressing ambient air in the low pressure compressor, cooling the compressed air using the intercooler, and then compressing the compressed air in the high pressure compressor to generate a first compressed air flow; and
directing the first compressed air flow from the high pressure compressor to the air storage tank; and
operating the compressed air energy storage system in an air injection mode by:
compressing ambient air in the low pressure compressor to generate a second compressed air flow, the second compressed air flow bypassing each of the intercooler and the high pressure compressor;
directing the first compressed air flow from the storage tank into the expander; and,
mixing the first compressed air flow downstream of the expander with the second compressed air flow to form an injection air flow; and
injecting the injection air flow into the gas turbine;
wherein, a pressure of the second compressed air flow is greater than a pressure of air in a compressor discharge plenum of the gas turbine.
12. The method of claim 11 , further comprising heating the second compressed air flow with a heater located between the gas turbine and the low pressure compressor.
13. The method of claim 11 , wherein the expander is a multi-stage expander.
14. A method of operating a compressed air energy storage system associated with a gas turbine, the compressed air energy storage system having an air storage tank in fluid communication with a multi-stage compressor and an expander, the multi-stage compressor comprising a low pressure compressor having an intercooler associated therewith and a high pressure compressor, the method comprising:
operating the compressed air energy storage system in an energy storage mode by:
compressing ambient air in the low pressure compressor, cooling the compressed air using the intercooler, and then compressing the compressed air in the high pressure compressor to generate a first compressed air flow; and
directing the first compressed air flow from the high pressure compressor to the air storage tank; and
operating the compressed air energy storage system in an air injection mode for injection into the gas turbine by:
compressing ambient air in the low pressure compressor to generate a second compressed air flow, the second compressed air flow bypassing each of the intercooler and the high pressure compressor;
wherein, a pressure of the second compressed air flow is greater than a pressure of air in a compressor discharge plenum of the gas turbine.