Combined Gas and Steam Turbines Dr. U. Tomschi, Siemens AG

Transcription

1 European Summer School 2015 Economic and Legal Aspects of the Electricity, Gas and Heat Market Combined Gas and Steam Turbines Dr. U. Tomschi, Siemens AG 1

2 Content Targets of Power Supply Importance of efficiency Steam turbine plants Gas turbine plants Gas and steam turbine plants Role in the supply system of the future

3 What are the targets of Power Supply? CO 2 -Emissions Other emissions Landscape consumption Consumption of ressources Sustainability η = Crucial parameter: Efficiency η ggggggggg eeeeee eeeeeeeeeee, kkkkk uuuu eeeeee cccc, ggg,, kkk tt Strong influence on emissions Strong influence on operational cost Security of supply Economy Reliability Availability (also of primary energy source) Controllability Support of technical system stability Development cost Investment Operational cost Residue handling cost Dismantling cost

4 Limits of efficiency Efficiency NEVER is 100% For thermodynamic cycle processes: Determined by temperature levels of heat transfer: η = 1 T lll T hhhh T high T high T low Water-steam cycle (Rankine) T low Gas turbine cycle (Joule) Primary energy Theoretical efficiency Limited by Typical values Effect on Coal 50-55% T in,t amb, materials 42-46% Emissions, op. cost Gas (Gas Turbine) 40-45% T in,t amb, materials 40% Emissions, op. cost Photovoltaic >20% Semiconductor material 12-16% Installed capacity Wind 59% mass balance 50% Installed capacity

5 Efficiency of thermal plants Net efficiency Combined gas and steam turbine (Combined Cycle Power Plant) Coal fired with reheat steam turbine Coal fired with fluidized combustion Combined cycle with integrated coal gasification Gas turbine

6 Conversion of Energy Power to gas Primary Energy Conversion Electrical Energy Kinetic energy rivers, tides, currents hydro turbine wind wind turbine Thermal energy geothermal Chemical energy Watersteam-cycle in steam turbines (Rankine cycle) Mechanical energy (rotation) Generator uranium coal, natural gas, oil, biofuels, hydrogen fission combustion thermal energy Gas turbines (Joule cycle) CO 2 Engines (Otto cycle) fuel cells Radiation sun photovoltaic

7 What is a steam power plant? Chemical Energy Boiler (HRSG/Reactor) Thermal Energy Steam Turbine Mechanical Energy Generator Electrical Energy Typical power output: MW

8 What is a steam power plant? LP turbine for NPP: centrifugal force 620 t per blade equal to take-off weight of an Airbus A380 SPP Schwarze Pumpe, Germany

9 What is a gas turbine power plant? η = P m F H L P = P T - P C - P L P C P T Circumferential acceleration to blades: g Transferred power per blade: 3,5 MW (SGT5-8000H) Typical power output: MW

10 What is a Combined Gas and Steam plant?

11 What is a Combined Gas and Steam plant? Efficiency: >60%!

12 Effect of fuel and efficiency on emissions: Change from hard coal to natural gas: CO 2 emission per thermal energy capacity Coal: ~400g/kWh th Natural gas: ~200g/kWh th Increase efficiency from 40% to 60% (on natural gas): 40%: 0,5 kg/kwh el 60%: 0,33 kg/kwh el on operational cost: Change from hard coal to natural gas: Coal: 5-6 /MWh th Natural Gas: 21 /MWh th (based on current EEX data, without CO2 certificate cost) Increase efficiency from 40% to 60% (on natural gas): 40%: 52,50 /kwh el 60%: 35 /kwh el

13 System stability and security of supply Tasks in the Grid: Voltage Control Frequency Control Load dispatch Normal operation New challenges with RE RE Fluctuations Stand by capacity Independency of fossil sources Dyn.Stability (FRT) Fast frequency changes Black Start, Grid Restoration Disturbed conditions Islanding 100ms 1 s 10 s 1 min 15 min 1 h 8 h 1 d 1 w 1 m 1 y 10 y 100 y Manyfold requirements to power plant dynamics!

14 Role of inertia in the system The electrical grid is a system of interconnected synchronous rotating machines. The less rotating mass (inertia) available, the less stable the system frequency and the higher the required dynamic capabilities of remaining plants. Wind and PV do not inherently provide inertia, synchronous machines do! A minimum amount of synchronous machines is necessary for system stability. Consumers with very limited inertia Synchronous generators with inertia Non-synchronous generators without inertia

15 Power to Gas to Power Electrical network Gas network Wind PV CCPP Power generation Power storage Gas storage CO 2 Electrolyser H 2 -storage CO 2 - storage Methanising Long term chemical storage in existing gas system: decoupling of generation and demand Ideal Integration of gas and power system on generation and demand side Reliable system stability with proven technology, high efficiency and flexibility

16 Role of thermal power plants in the system Contribution of thermal power plants: Reactive Power, Voltage Control Inertia& Stability Frequency response Fast load changes Hot start Power control Cold start Stand by capacity Power to Gas to Power Voltage Control Frequency Control Load following dispatch Dyn.Stability (FRT) Islanding Fast frequency changes RE Fluctuations Black Start, Grid Restoration Stand by capacity Independency of fossil sources 100ms 1 s 10 s 1 min 15 min 1 h 8 h 1 d 1 w 1 m 1 y 10 y 100 y System Stability Security of Supply

17 Role of thermal power plants in the system Contribution of thermal power plants: Reactive Power, Voltage Control Inertia& Stability Frequency response Fast load changes Hot start Power control Cold start Stand by capacity Power to Gas to Power Voltage Control Frequency Control Load following dispatch Dyn.Stability (FRT) Islanding Fast frequency changes RE Fluctuations Black Start, Grid Restoration Stand by capacity Independency of fossil sources 100ms 1 s 10 s 1 min 15 min 1 h 8 h 1 d 1 w 1 m 1 y 10 y 100 y System Stability Security of Supply

18 Summary Combined Gas and Steam plants - Have highest efficency among all fossil fired power plants and low specific emissions in kg CO2 per kwh - Provide all necessary system services for system stability - Have a high energy density per area and low invest cost - Can be used as CHP plant for optimum fuel utilization Sustainability - Can play central part in decarbonized H2 or CH4 power to gas to power system Security of supply Economy

19 Thank you for your attention! Questions? European Summer School

20 Contact Dr. Ulrich Tomschi Siemens AG Power&Gas Energy Solutions PG ES EN PTEC PE Freyeslebenstr Erlangen Germany Phone: +49 (9131) Mobile: +49 (152) ulrich.tomschi@siemens.com siemens.com/answers

21 Starts: operational regime and lifetime Typical operational regime of CCPP: Load ing rate Life time Hot starts /a (< 8 h) Warm starts/a (< 72 h) Cold starts /a past h future??? h ? ? 2-20? Cold starts Operational regime not predicable New design paradigm Hot starts Limitation of start up time by: - heating of relevant components, condensation - temperature stress in thick walled components - distorsion due to temperature gradients combination of number of starts and loading rate determines life time

22 Start up times: capabilities and limitations Startup time Definition Lignite Hard coal CCPP Hot start < 8 h standstill min (to Synchr.) min (to Synchr.) <30-60 min (to base load) Warm start <48 h standstill min Cold start <120 h standstill Several h Several h min

23 Share of Electricity on Primary Energie Sources in D

24 Targets of Energiewende