Hard Coal Steam Turbine

Hard Coal Steam Turbine#

The HardCoalSteamTurbine (HCST) class models a hard coal power production plant using steam turbines. This class is a subclass of ThermalComponentBase and inherits all state machine behavior, ramp constraints, and operational logic from the base class.

Set component_type: HardCoalSteamTurbine in the component’s YAML section. The section key is a user-chosen component_name (e.g. hard_coal_steam_turbine); see Component Names, Types, and Categories for details.

For details on the state machine, startup/shutdown behavior, and base parameters, see Thermal Component Base.

HCST-Specific Parameters#

The HCST class provides default values for bituminous coal properties from [4]:

Parameter	Units	Default	Description
`hhv`	J/m³	29310000000	Higher heating value of bituminous coal (29.31 MJ/kg) [4]
`fuel_density`	kg/m³	1000	Fuel density for mass calculations

The efficiency_table parameter is optional. If not provided, default values based on approximate readings from the [2] are used. All efficiency values are HHV (Higher Heating Value) net plant efficiencies. See Thermal Component Base for details on the efficiency table format.

Default Parameter Values#

The HardCoalSteamTurbine class provides default values for base class parameters based on References [1-4]. Only rated_capacity and initial_conditions.power are required in the YAML configuration.

Parameter	Default Value	Source
`min_stable_load_fraction`	0.30 (30%)	[2]
`ramp_rate_fraction`	0.03 (3%/min)	[1]
`run_up_rate_fraction`	Same as `ramp_rate_fraction`	—
`hot_startup_time`	7.5 hours	[1]
`warm_startup_time`	7.5 hours	[1]
`cold_startup_time`	7.5 hours	[1]
`min_up_time`	48 hours	[2]
`min_down_time`	48 hours	[2]
`efficiency_table`	Average plant efficiency	[2,3]

Default Efficiency Table#

The default HHV net plant efficiency table is based on [2,3]:

Power Fraction	HHV Net Efficiency
1.00	0.35 (35%)
0.5o	0.32 (32%)
0.30	0.30 (30%)

HCST Outputs#

The HCST model provides the following outputs (inherited from base class):

Output	Units	Description
`power`	kW	Actual power output
`state`	integer	Operating state number (0-5), corresponding to the `STATES` enum
`efficiency`	fraction (0-1)	Current HHV net plant efficiency
`fuel_volume_rate`	m³/s	Fuel volume flow rate
`fuel_mass_rate`	kg/s	Fuel mass flow rate (computed using `fuel_density`

Efficiency and Fuel Rate#

HHV net plant efficiency varies with load based on the efficiency_table. The fuel volume rate is calculated as:

\[ \text{fuel\_volume\_rate} = \frac{\text{power}}{\text{efficiency} \times \text{hhv}} \]

Where:

power is in W (converted from kW internally)
efficiency is the HHV net efficiency interpolated from the efficiency table
hhv is the higher heating value in J/m³
Result is fuel volume rate in m³/s

The fuel mass rate is then computed from the volume rate using the fuel density:

\[ \text{fuel\_mass\_rate} = \text{fuel\_volume\_rate} \times \text{fuel\_density} \]

Where:

fuel_volume_rate is in m³/s
fuel_density is in kg/m³
Result is fuel mass rate in kg/s

YAML Configuration#

Minimal Configuration#

Required parameters only (uses defaults for hhv, efficiency_table, and other parameters):

hard_coal_steam_turbine:
  component_type: HardCoalSteamTurbine
  rated_capacity: 100000  # kW (100 MW)
  initial_conditions:
    power: 0  # 0 kW means OFF; power > 0 means ON

Full Configuration#

All parameters explicitly specified:

hard_coal_steam_turbine:
  component_type: HardCoalSteamTurbine
  rated_capacity: 500000  # kW (500 MW)
  min_stable_load_fraction: 0.3  # 30% minimum operating point
  ramp_rate_fraction: 0.03  # 3%/min ramp rate
  run_up_rate_fraction: 0.02  # 2%/min run up rate
  hot_startup_time: 27000.0  # 7.5 hours
  warm_startup_time: 27000.0  # 7.5 hours
  cold_startup_time: 27000.0  # 7.5 hours
  min_up_time: 172800  # 48 hours
  min_down_time: 172800  # 48 hour
  hhv: 29310000000  # J/m³ for bituminous coal (29.31 MJ/m³) [4]
  fuel_density: 1000  # kg/m³ for bituminous coal
  efficiency_table:
    power_fraction:
      - 1.0
      - 0.50
      - 0.30
    efficiency:  # HHV net plant efficiency, fractions (0-1)
      - 0.35
      - 0.32
      - 0.32
  log_channels:
    - power
    - fuel_volume_rate
    - fuel_mass_rate
    - state
    - efficiency
    - power_setpoint
  initial_conditions:
    power: 0  # 0 kW means OFF; power > 0 means ON

Logging Configuration#

The log_channels parameter controls which outputs are written to the HDF5 output file.

Available Channels:

power: Actual power output in kW (always logged)
state: Operating state number (0-5), corresponding to the STATES enum
fuel_volume_rate: Fuel volume flow rate in m³/s
fuel_mass_rate: Fuel mass flow rate in kg/s
efficiency: Current HHV net plant efficiency (0-1)
power_setpoint: Requested power setpoint in kW

References#

Agora Energiewende (2017): “Flexibility in thermal power plants - With a focus on existing coal-fired power plants.”
IRENA (2019), Innovation landscape brief: Flexibility in conventional power plants, International Renewable Energy Agency, Abu Dhabi.
T. Schmitt, S. Leptinsky, M. Turner, A. Zoelle, C. White, S. Hughes, S. Homsy, et al. “Cost And Performance Baseline for Fossil Energy Plants Volume 1: Bituminous Coal and Natural Gas Electricity.” Pittsburgh, PA: National Energy Technology Laboratory, October 14, 2022b. https://doi.org/10.2172/1893822.
I. Staffell, “The Energy and Fuel Data Sheet,” University of Birmingham, March 2011. https://claverton-energy.com/cms4/wp-content/uploads/2012/08/the_energy_and_fuel_data_sheet.pdf