Prairieland 2050: design and defend a nation’s pathway
Choose a pathway for five regions to 2050, test it against four shocks, and defend its cost, emissions, security, affordability and Ridge County’s jobs in a two-page policy brief
Capstone C4 of Energy Systems, Step by Step: choose a fictional nation’s pathway to 2050 on the Pathway Explorer’s engine, test it against a gas-price spike, a drought, a mineral export restriction and a demand surprise, and defend it in a two-page policy brief with its cost, emissions against a cumulative budget, security, screening affordability and a coal county’s jobs.
The brief
Prairieland's energy minister wants a pathway to 2050 for its five regions, and its defence: cost, CO₂ against the budget, security, who pays and Ridge County's jobs.
Also: how the pathway holds up against a gas-price spike, a drought, a mineral export restriction and a demand surprise.
- Hand in: a pathway link, a two-page policy brief (with the shock table as its sensitivity and what would change your recommendation), and the lines M13's notebook prints for the same pathway.
- From: the Pathway Explorer's engine, its costs and fuels within their fixed ranges, and lesson A13's accounting layer for who pays and for jobs (Prairieland is fictional; its numbers are illustrative).
- Done when: every check under the brief is in place, and the self-check reaches Proficient on every competence.
About 240 minutes: 70 to build and test pathways, 30 to read the results, 40 to run your pathway in M13's notebook, 70 to write the brief, 30 to check it.
- Units
- Power in GW; energy in TWh and PJ (1 TWh = 3.6 PJ; 1 PJ = a million GJ); CO₂ in Mt, million tonnes; fuel prices per GJ on net calorific values.
- Terms
- Primary energy: fuels as found, before conversion. LNG: liquefied natural gas. The LP's dual: the modelled cost change from tightening the budget by one tonne.
Build and test your pathway
| Control | Default plan | Range |
|---|---|---|
| Demand growth | Central | one of: Low growth, Central, High growth |
| Buildings: electricity's share of useful energy in 2050 | 80 % | 54 to 100 %, in steps of 1 % |
| Transport: electricity's share of useful energy in 2050 | 50 % | 3 to 78 %, in steps of 1 % |
| Industry: electricity's share of useful energy in 2050 | 55 % | 40 to 60 %, in steps of 1 % |
| Carbon budget, 2026-2050 | 3,600 Mt | 500 to 5,400 Mt, in steps of 100 Mt |
| Counting the years between | Straight lines between model years | one of: Straight lines between model years, Each model year for its five years |
| Import share cap, each model year | 40 % | 10 to 60 %, in steps of 5 % |
| Foresight | Perfect foresight (2030-2050 at once) | one of: Perfect foresight (2030-2050 at once), Decade by decade |
| Peak-hour reserve rule | Stress hours + 10% | one of: No peak-hour rule, Meet the stress hours, Stress hours + 10%, Stress hours + 20% |
| Generic firm clean option allowed | 1 | 0 to 1, in steps of 1 |
| New transmission allowed | 1 | 0 to 1, in steps of 1 |
| Early retirement of fossil plants allowed | 1 | 0 to 1, in steps of 1 |
| Wind farm, capital | 1,712 $/kW | 1,500 to 2,400 $/kW, in steps of 1 $/kW |
| Solar farm, capital | 1,484 $/kW | 1,350 to 1,900 $/kW, in steps of 1 $/kW |
| Battery (4 hours), capital | 1,521 $/kW | 1,380 to 1,690 $/kW, in steps of 1 $/kW |
| Gas combined cycle, capital | 1,032 $/kW | 850 to 1,400 $/kW, in steps of 1 $/kW |
| Gas turbine, capital | 1,158 $/kW | 950 to 1,580 $/kW, in steps of 1 $/kW |
| Generic firm clean plant, capital | 7,000 $/kW | 3,000 to 11,000 $/kW, in steps of 10 $/kW |
| New transmission | 1,500 $/MW-km | 800 to 3,000 $/MW-km, in steps of 50 $/MW-km |
| Domestic gas | 4.05 $/GJ | 2 to 9 $/GJ, in steps of 0.01 $/GJ |
| LNG imports | 10 $/GJ | 6 to 30 $/GJ, in steps of 0.5 $/GJ |
| Coal | 2.41 $/GJ | 1.5 to 4 $/GJ, in steps of 0.01 $/GJ |
| Crude oil | 12 $/GJ | 7 to 22 $/GJ, in steps of 0.5 $/GJ |
| Discount rate (real) | 5 % | 2 to 8 %, in steps of 0.5 % |
| Households pay this share of the change in yearly cost | 50 % | 0 to 100 %, in steps of 10 % |
| Households' share recovered | Per kWh | one of: Per kWh, Fixed charge, By income |
| Jobs multiplier (direct to total) | 1.6 × | 1 to 2.5 ×, in steps of 0.1 × |
| Displacement: new work that would have happened anyway | 20 % | 0 to 50 %, in steps of 5 % |
With JavaScript on, you change the pathway, run it with its four shocks in your browser and copy a link to it. Without it, write the brief on the default pathway: its evidence is in the results below. Prairieland is fictional; its numbers are illustrative.
| Result: the default pathway (Central: electrify, budget 3,600 Mt) | Value |
|---|---|
| Cost 2026–2050, present value in 2025 (2025 dollars; supply side and every fuel bought) | $401.6 billion |
| CO₂ 2026–2050 against the budget | 3,600 of 3,600 Mt |
| CO₂ a year, 2030, 2035, 2040, 2045, 2050 | 171, 142, 130, 123, 115 Mt |
| Imports, share of primary energy, 2030, 2035, 2040, 2045, 2050 | 32%, 32%, 30%, 27%, 24% (cap 40%) |
| Clean share of electricity, 2030 and 2050 | 83% and 90% |
| Built 2026–2050: wind, solar, gas, batteries, firm clean (generic) | 72.0 GW, 32.5 GW, 35.5 GW, 0.0 GW, 3.3 GW |
| New transmission | 8.9 GW |
| The budget's marginal value (the LP's dual: what one more tonne allowed would save) | $48 a tonne, present value in 2025 |
| Ridge Station (2,400 MW of coal) | closed by 2040 |
Precomputed with this engine on 7 November 2026: one linear program over 2030–2050 on twelve time slices. Prairieland is fictional; its numbers are illustrative. With JavaScript on, the bench runs your own plan.
| Shock (model year) | Cost to 2050, against the plan | CO₂ 2026–2050 | Imports that year | Peak-hour rule that year | Not served that year |
|---|---|---|---|---|---|
| Gas-price spike (2030) | +$11.7 billion | 3,600 Mt | 30% | met | none |
| Drought (2035) | +$2.0 billion | 3,600 Mt | 34% | 5,021 MW short | none |
| Mineral export restriction (2035) | $0.0 billion | 3,600 Mt | 32% | met | none |
| Demand surprise (2035) | +$26.5 billion | 3,600 Mt | 36% | 4,766 MW short | none |
| Screening (A13's accounting layer) | Value |
|---|---|
| Households' change in 2050 at 50% (against the 2025-policies pathway; equipment left out) | −$130 a household a year |
| Ridge County: jobs lost (Ridge Station and the mines, × 1.6) | 5,533 |
| Ridge County: new ongoing jobs, gross and net of 20% displacement (if all the Ridge region's new wind and solar is in the county) | 1,152 and 922 |
| Ridge County: construction job-years, gross and net | 49,306 and 39,444 |
- Illustrative: Prairieland, its regions, fleet, links, demand, shocks and Ridge County (prairieland.json); the existing plants' operating costs, the penalties and the peak-hour rule (e4-pathways.json); A13's jobs coefficients.
- Based on public data: new plants' costs from EIA's 2026 assumptions, fuel prices from EIA's 2025 data, CO₂ factors from the IPCC, hourly shapes from SPP's 2025 and 2024 grid.
- Left out of every cost: end-use equipment (heat pumps, cars, boilers), so a pathway that electrifies more looks cheaper than it would be for households.
- Who pays and jobs: A13's accounting layer: screening estimates with stated assumptions, not outputs of the linear program; Prairie City's five household groups stand in for Prairieland's.
- Precomputed: the presets (perfect foresight and decade by decade) with their shocks and full-year checks come from a library made with this engine; any other pathway runs in your browser.
- Against lesson A20: no pathway here gets below about 2,700 Mt (straight-line counting, central demand). A20 meets 2,600 Mt because its fastest path electrifies buildings and industry years sooner.
Write your two-page policy brief
- Title and plan link: the plan's link from the bench, and the date
- Recommendation: Three or four sentences: the pathway Prairieland should take to 2050, and why.
- The plan: each choice, with its unit
- Results: each result, with its unit and boundary
- Assumptions: one sentence each
- Sensitivity: how one result moves when one input changes, and whether the plan was held fixed
- Cost, carbon and security: Two or three sentences: the cost, CO₂ against the budget, imports against the cap.
- Shocks and what would change the recommendation: Two or three sentences: what the four shocks did, and which result would make you choose differently.
- Who pays, and Ridge County: Two or three sentences: households (a screening estimate, with your share and design) and Ridge County's jobs, gross and net.
- M13's notebook on your pathway: Paste the lines its section 8 printed for your plan (cost, CO₂, imports, what it builds) and say whether they match the page.
- Sources and credit: One or two sentences: the data behind your numbers (EIA, IPCC, SPP through EIA-930; the course's teaching settings) and any conflict of interest.
- Limits of this analysis: what the model leaves out
Part of the hand-in · your pathway in M13's notebook, about 40 minutes
- Open M13's notebook with its three data files, as you did in M13.
- In its section 8, set
MY =to your pathway's levers (the Pathway Explorer's keys). - Run it. It solves the same linear program and prints the cost, CO₂ by model year, imports, what it builds and a link to the same plan.
- Paste those lines into the brief's notebook field, and say whether they match the page.
Check your brief
Weak brief · Developing
Prairieland should go renewable [1]. It meets the climate goal [2] and is secure [3]. Ridge County will be fine [4].
- Falls short: No sizes or years: what is built, where, and when?
- Falls short: Which budget, on what boundary, by how much?
- Falls short: Against what? Imports, the strait, the peak hours: name the measure and the shocks.
- Falls short: Jobs lost and gained, gross and net, with the coefficients stated.
Strong brief · Proficient
Recommendation: follow the central pathway: by 2050 build 72.0 GW of wind, 32.5 GW of solar, 35.5 GW of gas, 0.0 GW of batteries and 3.3 GW of the generic firm option, and widen links by 8.9 GW [1]. Why this one: a security-first plan (imports at most 25%) costs $109.6 billion more and still cannot meet its cap in 2030 [2]. Cost and carbon: $401.6 billion to 2050 (present value, 2025 dollars, supply side and every fuel); CO₂ 3,600 of 3,600 Mt [3]. Security: imports at most 32% of primary energy against a 40% cap [4]. Shocks: Cost: against the four shocks, each re-planned from its year, the cost to 2050 moves by $0.0 billion to +$26.5 billion, most for the demand surprise. Carbon: the budget is met under all four. Imports: within the cap under all four. Peak hours: short in the shock's year under the drought and the demand surprise. [5] What would change it: the demand surprise costs most (+$26.5 billion) and leaves the stress hours 4,766 MW short in 2035; if it looked likely, I would build more firm capacity before 2035 [6]. Who pays (screening): about $−130 a household a year in 2050 if households pay 50%; equipment not counted [7]. Ridge County (screening): 5,533 jobs lost against 1,152 new ongoing jobs (922 net), with a multiplier of 1.6, 20% displacement and all the Ridge region's new wind and solar in the county [8]. Limits: twelve slices, no clean fuels for the oil and gas that stay, perfect foresight; the full-year check passes 4 of 4, with CO₂ up to 8% above the slices, and does not test the budget [9].
- Works: Every lever with its size.
- Works: A reason against another pathway, from a second run.
- Works: One boundary, the budget's arithmetic stated.
- Works: A measure and its limit.
- Works: All four, with the rule for what was kept, as a range.
- Works: The result that would change the recommendation, named.
- Works: A screening estimate with its share and what it leaves out.
- Works: Gross and net kept apart; the multiplier, displacement and the county assumption stated.
- Works: What the model leaves out, and what the checks do and do not show.
| Weak brief | Strong brief | |
|---|---|---|
| Sizes | none | every lever |
| Boundary | none | stated |
| Shocks | none | all four, a range |
| Reversal | none | named |
| Jobs | none | gross and net |
| Competence | Developing | Proficient (the bar for this policy brief) | Strong |
|---|---|---|---|
| Consistent accounting Look for: Cost and CO₂ on one boundary (the nation, 2026–2050, 2025 dollars, fuels burned inside Prairieland); imports against the cap; affordability and jobs as screening estimates, gross and net kept apart. |
Costs and emissions on different boundaries. | Cost and emissions on one boundary; emissions question named; who pays and who benefits named. | Distributional and environmental side effects estimated with stated assumptions. |
| Uncertainty Look for: All four shocks reported as ranges, with the rule for what was kept; the result that would change the recommendation named. |
Single numbers. | The four shocks re-planned on this plan and reported (cost, budget, imports, the peak-hour rule), the range stated, and the shock or assumption that would flip the recommendation named. | Decision-relevant uncertainty identified and its value discussed. |
| Realism Look for: What the model leaves out: equipment costs, clean fuels, foresight, outages; whether the full-year check is known for this plan. |
Assumes announced projects exist. | Evidence status of key inputs; a 'what the analysis leaves out' list. | Realism checked with a practitioner or primary documents. |
| Communication Look for: Two pages a minister can act on: the recommendation first, then the evidence, the shocks, who pays, Ridge County and the limits; the notebook's run of the same pathway. |
Results without limits. | A two-page policy brief with the pathway link and the notebook's run of the same plan: the recommendation first, then cost, carbon and security, the shocks with their range, who pays and Ridge County (gross and net), and the limits. | A briefing a decision-maker could act on without misreading. |
Numbers, sources and what’s next
Inputs the engine uses
| Input (2025 dollars) | Default | Range you can set (set for teaching) | Source, and the source's own range |
|---|---|---|---|
| Wind farm, capital | $1,712/kW (EIA Table 3) | $1,500/kW to $2,400/kW | EIA AEO2026 Table 4, its regions: $1,478/kW to $4,335/kW |
| Solar farm, capital | $1,484/kW (EIA Table 3) | $1,350/kW to $1,900/kW | EIA AEO2026 Table 4, its regions: $1,342/kW to $1,949/kW |
| Battery (4 hours, 85% round trip), capital | $1,521/kW (EIA Table 3) | $1,380/kW to $1,690/kW | NREL's 2025 battery update (low) and EIA AEO2026 Table 4 (high): $1,371/kW to $1,698/kW |
| Gas combined cycle, capital | $1,032/kW (EIA Table 3) | $850/kW to $1,400/kW | EIA AEO2026 Table 4, its regions: $830/kW to $1,445/kW |
| Gas turbine, capital | $1,158/kW (EIA Table 3) | $950/kW to $1,580/kW | EIA AEO2026 Table 4, its regions: $946/kW to $1,585/kW |
| Generic firm clean plant, capital | $7,000/kW (set for teaching) | $3,000/kW to $11,000/kW | EIA AEO2026 Table 4, firm low-carbon plants that burn no fuel: $2,685/kW to $11,568/kW |
| New transmission | $1,500 per MW-km (set for teaching) | $800 per MW-km to $3,000 per MW-km | set for teaching |
| Domestic gas | $4.05/GJ (EIA, 2025: $3.85 per MMBtu, on net calorific values) | $2.00/GJ to $9.00/GJ | EIA Electric Power Annual, Table 7.4 |
| LNG imports | $10.00/GJ (set for teaching) | $6.00/GJ to $30.00/GJ | set for teaching |
| Coal (Ridge County) | $2.41/GJ (EIA, 2025: $2.42 per MMBtu, on net calorific values) | $1.50/GJ to $4.00/GJ | EIA Electric Power Annual, Table 7.4 |
| Crude oil | $12.00/GJ (set for teaching: about $70 a barrel) | $7.00/GJ to $22.00/GJ | set for teaching |
| CO₂ factors: crude oil, gas, coal | 73.3, 56.1, 94.6 t per TJ | fixed | IPCC 2006 Guidelines, Volume 2, net calorific values |
| Build limits, a region a period | wind 6, solar 8, batteries 6, gas 4 + 4, firm 2 GW | fixed | set for teaching: one generic rule, no technology's own timeline |
| Discount rate (real) | 5% (set for teaching) | 2% to 8% | set for teaching |
| Hourly shapes | SPP's 2025 grid (slices); 2024 for the independent year | fixed | EIA Hourly Electric Grid Monitor (Form EIA-930) |
Keep going
Sources and further reading
- U.S. Energy Information Administration (April 2026). Assumptions to the Annual Energy Outlook 2026: Electricity Market Module, Tables 3 and 4 (read 7 Nov 2026).
- Intergovernmental Panel on Climate Change (2006). 2006 IPCC Guidelines for National Greenhouse Gas Inventories, Volume 2: Energy, chapters 1 and 2.
- International Energy Agency. Oil stocks of IEA countries: members that import oil hold at least 90 days of net imports (read 2 Nov 2026).
- National Laboratory of the Rockies (formerly NREL). Interpreting JEDI Results: construction and operating jobs, direct and supply-chain (last updated 28 Jan 2026).
- DeCarolis, J., et al. (2017). Formalizing best practice for energy system optimization modelling. Applied Energy, 194, 184–198.
- Trutnevyte, E. (2016). Does cost optimization approximate the real-world energy transition? Energy, 106, 182–193.
Spotted an error, or stuck? Write to hlli@ksu.edu. Corrections are made in place and dated here.
Text licensed CC BY 4.0, code MIT: teachers and students may reuse and adapt it, with credit to Honglin Li.