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L04 / Generation mix planning

Generation Mix Planning II

Build screening curves, find cost crossovers, form net load, and check a generation portfolio.

Available28 slides
Cost screening and generation mix

01 / UNDERSTAND & PREDICT

Understand the model, then predict the result

Finalized lecture slides

Open / download original PDF ↗

Follow the original explanations, diagrams, derivations, and examples in slide order, then use the companion experiment below.

L04 original slide 1 of 28
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Slide text
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Figures and page order follow the student PDF for this lecture.

Do 4380 MW peak, 4850 MW accredited capacity, and 15% reserve agree? Is the GT/CC choice the same at 2000 and 6000 operating hours?
  • Sort a load record and verify unchanged energy.
  • Calculate reserve capacity targets and GT/CC crossover hours.
  • Cover net load, then check accredited reserve and identify the simplifications.
Generation fleet mix: concept and calculation route
Course-authored concept route; the numerical experiment follows below.

Screening cost curves

c(T)=F+vT,\qquad T^*=\frac{F_{CC}-F_{GT}}{v_{GT}-v_{CC}}

F is in $/MW-year, v in $/MWh, and T in h/year. Equating annual costs gives crossover hours; parallel curves may have no unique crossover.

From MW layers to unit counts

The L04 annual levels are 4200, 3400, 2600, 1800 MW at 0, 1000, 4000, 7000, 8760 h. Constant renewable output forms this simplified net load. Compare each MW layer, round CC at 543 MW and GT at 211 MW, then add GT for reserve.

Baseline example: check each step

  1. L03: twelve two-hour blocks total 77960 MWh; peak is 4380 MW.
  2. Current PRM ≈ 10.731%; the 15% target is 5037 MW, leaving 187 MW.
  3. GT/CC crossover is ≈ 4511.481 h/year; GT costs less at 2000 h.
  4. The simplified L04 net load assigns 1800 MW to CC; rounding to four CC units leaves six GT units for peak coverage.
  5. Default renewable capacity credit is zero; seven additional GT units give 4915 MW ≥ the 4830 MW reserve target.
Original slide headings for this lecture25
  1. 1One capacity target, many possible mixes
  2. 2Planning questions
  3. 3Why build a screening curve?
  4. 4One technology, one screening curve
  5. 5Concept 1: annual fixed-cost coefficient
  6. 6Example 1: annual fixed cost
  7. 7Concept 2: variable operating cost
  8. 8Example 2: variable operating cost
  9. 9Concept 3: build one screening curve
  10. 10Concept 4: curve crossover
  11. 11Example 3: simple cycle vs. combined cycle
  12. 12Four technologies for the case
  13. 13From load to net load
  14. 14Case inputs
  15. 15Place wind and solar
  16. 16Form the NLDC
  17. 17Recall the GT–CC crossover
  18. 18Map crossover to MW
  19. 19Round CC units
  20. 20Round GT units for peak load
  21. 21Check every load block
  22. 22Add PRM after load matching
  23. 23Repeat the planning loop
  24. 24How the two lectures connect
  25. 25Summary
Cross-check the original slides

02 / EXPLORE

Change one input and explain the response

Set equal GT and CC variable costs and inspect the lack of a unique crossover. Change capacity credit and explain why energy output and reserve credit are separate inputs.

Advanced parameters / test readings

Preparing the model.

L03 daily energy—
L03 accredited capacity gap—
Cost crossover—
L04 mix accredited capacity—
CC units—
GT units for net load—
Additional GT for reserve—
L04 reserve capacity target—

L03: chronological and sorted load

L04: annual screening costs

Current intermediate values and numerical checks
Renewable output blocks are constant and capacity credit is a separate input. Rounding and adding GT give a feasible teaching portfolio; costs use fixed/variable coefficients without startup or ramp constraints.
03 / EDIT & COMPUTE
Edit code to reproduce the model independently
Reproduce the baseline, then modify the parameter scan. The source contains reusable independent model functions; edit the current function and inspect numerical checks.
case is a snapshot of the controls when you press Run. Call solve(case) and assign the final solution to result to plot it.
 
Download teaching models
The first run needs internet access to download Python. Computation stays in your browser; the solver uses only the standard library.
Ready to run.
Output appears here.
Inspect and edit the model source (advanced)
Edit this module's function and run again. case.module selects the module; solve(case) returns values, plots, and checks. The parameter experiment keeps the original JavaScript reference for comparison.
04 / CHECK & EXPLAIN
Companion experiment practice and feedback
Fixed practice inputs
Original L03 twelve two-hour MW blocks: 2500, 2300, 2200, 2400, 2900, 3500, 4000, 4200, 3900, 4380, 3700, 3000. Accredited capacity 4850 MW, PRM 15%; L04 GT: 217000+40.901T, CC: 284000+26.05T.
Practice uses fixed baseline inputs independently of the controls. Each field displays its tolerance.
±0.5 MWh
±0.05 MW
±0.5 h/year
  
Which information is preserved by sorting a load-duration curve?
Finally, explain in your own words
  1. What are the inputs, references, and main assumptions?
  2. Set equal GT and CC variable costs and inspect the lack of a unique crossover. Change capacity credit and explain why energy output and reserve credit are separate inputs.
  3. Did your code edit change physical parameters, the method, or representation bases? Which check helps identify that?
Passing numerical and understanding checks records this lecture’s companion practice as “practice checks passed.”