Lecture 8 Energy Conversion Technologies: Fossil, Nuclear, Hydro, and Others

Gang He

October 30, 2023

Sample analytic questions

• How much coal can be saved/emissions can be mitigated if China’s average coal power efficiency increased by 1 percentage point?
  
• Why combined heat and power saves energy?
• What are the challenges for nuclear expansion?
  
• How to best use pumped-dydro storage?

Thermodynamics

• Thermodynamic efficiency
  
• Comparing different technologies
  
• Thermodynamics provides physic limits

Heat engine

Heat -> Mechanical energy (work)

Laws of thermodynamics

• Zeroth law
  “If two systems are each in thermal equilibrium with a third, they are also in thermal equilibrium with each other.”

• First law
  “In a process without transfer of matter, the change in internal energy, \(\Delta U\), of a thermodynamic system is equal to the energy gained as heat, \(Q\), less the thermodynamic work, \(W\), done by the system on its surroundings.”

• Second law
  “Heat does not spontaneously flow from a colder body to a hotter body.”

• Third law
  “As the temperature of a system approaches absolute zero, all processes cease and the entropy of the system approaches a minimum value.”

Three efficiencies

• 1st law: actual, thermal efficiency;
  \(\eta_1 =\frac{W_{net}}{Q_{in}}=\frac{Q_{high}-Q_{low}}{Q_{high}}=1-\frac{Q_{low}}{Q_{high}}\)
• Carnot: maximum possible efficiency;
  \(\eta_c =\frac{W_{net}}{Q_{high}}=\frac{T_{high}-T_{low}}{T_{high}}=1-\frac{T_{low}}{T_{high}}\) (Kelvin)
  
• 2nd law: comparing 1st and Carnot;
  \(\eta_2 =\frac{\eta_1}{\eta_c}\)

A gas turbine engine

A steam coal plant

Brayton cycle vs. Rankine cycle

Jet engine, gas turbine

Steam engine, steam turbine

Brayton cycle vs. Rankine cycle

Brayton Cycle	Rankine Cycle
Jet, Gas turbine	Steam turbine
Open	Open/closed circuits
Working fluid in gaseous phase	Working fluid phase change

Largest coal plant in the U.S.

Georgia Power plant Scherer (3,720 MW)

Can you identify the components

• Coal storage
  
• Generating unit
  
• Cooling stack
  
• Bottom ash landfill
  
• Sub-station
  
• Transimission lines
  
• Waste/pollution management
  

Combined cycle

CCGT diagram

Recall updating Rosenfeld Plant?

	2010	2021
Size (MW)	500	940
Capacity Factor	70%	43%
Generation (TWh/yr)	~ 3	~ 3.6
Emissions (Mt/yr)	~ 3	~ 3.5

• NYC electricity use in 2020: ~4 TWh/year

Nuclear

Nuclear fission

Nuclear fussion

Nuclear power plants

Nuclear plant design

Diagram of a boiling-water nuclear reactor

Diagram of a pressurized-water nuclear reactor

Nuclear fuel cycle

Social > technology challenges

• Public engagement
  
• Lower capital costs
  
• Social and decision sciences
  
• Science and technology study
  
• Nuclear waste siting
  
• Best practices

Next generation of nuclear technology

• Modality
  
• Lower capital costs
  
• Siting flexibility
  
• Higher efficiency
  
• Safe and security
  
• Industry and manufacture
  
• Economic

Livermore Fusion breakthrough

Hydro

Hydropower

Pumped storage hydropower (PSH)

\(E=\rho mg(h_2-h_1)\)

How a lithium-ion battery works

Battery management system

• Rated power capacity
  
• Energy capacity
  
• Storage duration
  
• Cycle life/lifetime
  
• Self-discharge
  
• State of charge
  
• Round-trip efficiency

Long duration storage

Summary

• Theory - learn and understand the physics of energy technologies:
  • thermaldynamics (fossil)
    
  • kinematics (wind)
    
  • light and semiconductor (solar)
    
  • gravity (hydro, tidal)
    
  • atomic (nuclear)
    
• Practice - learn all kinds of corrections based on real-world situation
  
• The physics doesn’t change, corrections help us to do better jobs in simulation and projections

References

Dowling, Jacqueline A., Katherine Z. Rinaldi, Tyler H. Ruggles, Steven J. Davis, Mengyao Yuan, Fan Tong, Nathan S. Lewis, and Ken Caldeira. 2020. “Role of Long-Duration Energy Storage in Variable Renewable Electricity Systems.” Joule 4 (9): 1907–28. https://doi.org/10.1016/j.joule.2020.07.007.

Koomey, Jonathan, Hashem Akbari, Carl Blumstein, Marilyn Brown, Richard Brown, Chris Calwell, Sheryl Carter, et al. 2010. “Defining a Standard Metric for Electricity Savings.” Environmental Research Letters 5 (1): 014017. https://iopscience.iop.org/article/10.1088/1748-9326/5/1/014017.