Memo 25 · ROI · Energy · Net Zero
The Net Zero Path to 2050 Target
1,000 GW of desert solar plus 40 GW of Alice Hub pumped hydro is the SBC mainstay.
Read →What the SBC costs to build, what it returns at maturity, what Australia spends if it doesn’t build it. Full detail in Memo 19, Memo 20, and Memo 21.
The economic case rests on three numbers: what the programme costs to build, what it returns at maturity, and what Australia spends if it doesn’t build it. All figures at 10–15% design maturity — the same maturity at which the High Speed Rail Authority business case was submitted. Every assumption named in the source memos.
From Memo 19 — The SBC Cost Breakdown. Phase-by-phase capex over a 20+ year build, at current unit rates before full volume-production effects on later phases.
| Phase | Distance | Capex (current rates) | Note |
|---|---|---|---|
| Phase 0 spine | 2,284 km | $138–257 B | Melbourne–Brisbane inland, proving build |
| Phase 0 spurs (7) | 3,310 km | $203–381 B | Hunter, Sydney, QLD coast, Adelaide, Eden |
| Phase 1 | 6,775 km | $147–241 B | First continental (SBC #1, #2, Perth–Albany) |
| Phase 2 | 5,416 km | $98–164 B | Northern corridors (SBC #3, #4) |
| Phase 3 | 5,413 km | $98–164 B | Network closure (SBC #5, #6) |
| Alice Hub | n/a | $65–133 B | PHES + trunk aqueduct + finger viaducts + pumps |
| TOTAL programme | 23,200 km | $750–1,340 B | Over 20+ years |
From Memo 20 — The SBC Return on Investment. Three-tier framework: direct revenue defended at the dollar level, enabled outcomes captured through tax flowback, cascading economic activation named but not summed (the Snowy 1.0 lesson — some uplift cannot be honestly multiplied without losing credibility).
| Return tier | Annual at maturity | What it captures |
|---|---|---|
| Tier 1 — Direct revenue | $170–231 B/yr | HVDC export, transmission fees, freight tolls, maglev fares, water sales, AI compute, carbon credits — revenue on the SBC’s own balance sheet |
| Tier 2 — Enabled outcomes | $94–172 B/yr Commonwealth share via tax flowback |
Manufacturing revival, agricultural production uplift (M-D drought-proofing + agrivoltaic), reduced fuel imports, sovereign defence and export industries (processed minerals, regional grid construction, defence exports), sovereign space industry, avoided programme spend |
| Tier 1 + 2 SUBTOTAL | $264–403 B/yr | Defensible monetised return at maturity, no multipliers applied |
| Tier 3 — Cascading activation | Named, not summed | Cheap electricity, cheap gas, maglev mobility, freight reform, inland housing supply, renewable transition, sovereign manufacturing, regional integration — materially larger in aggregate than Tier 1+2 |
From Memo 21 — Without the SBC. The alternative is not “no spend.” The alternative is the same money, fragmented — on disconnected programmes that do not compound, do not self-fund, and do not deliver the integrated outcomes.
| Sector | 20-year commitment | What it does not deliver |
|---|---|---|
| Water | $185–337 B | No continental water transfer; M-D not drought-proofed; inland remains water-limited |
| Energy | $312–520 B ($565–1,040 B if nuclear pursued) |
No sub-10c/kWh; storage at 25× Alice Hub cost; no HVDC export industry |
| Transport | $213–843 B ($843 B if HSRA in full) |
Passenger-only HSRA at BCR 0.2; no maglev; freight stays on road; no integrated network |
| Defence | $1,108–1,638 B | AUKUS Pillar 1 unchanged; imported fuel dependency continues; no sovereign manufacturing |
| Manufacturing + housing | $210–410 B | Continuing smelter bailouts; no structural housing supply; coastal capital congestion continues |
| Renewable transition | $350–690 B | Under-scale build-out; net zero target slips; no renewable export market |
| TOTAL without SBC | $2,700–4,400 B | Approximately 2–3× the SBC programme cost |
The same numbers, broken down by the eleven MMA pillars. Where revenue lives in Tier 1 of Memo 20 it appears here; where the pillar’s value lives in the integrated programme rather than as a standalone revenue stream, that is noted explicitly.
| Pillar | Tier 1 revenue at maturity | Tier 2 enabled / Tier 3 cascade | Detail |
|---|---|---|---|
| Water | $3–5 B/yr (water delivery) | $39–77 B/yr agricultural production uplift industry revenue ($10–19 B/yr Commonwealth share) | Memo 5, Memo 20 §3.2 |
| Energy | $57 B/yr (HVDC export) + $12–19 B/yr (transmission) | $75 B/yr carbon credits; cheap-electricity cascade (Tier 3) | Memo 20 §2.1, 2.2, 2.8 |
| AI & Compute | $15–20 B/yr | Sovereign AI compute capability; capital migration cascade (Tier 3) | Memo 20 §2.6 |
| Passenger | $3–6 B/yr (maglev fares) | Labour mobility, regional services growth, housing pressure spread (Tier 3) | Memo 20 §2.4, 4.3 |
| Freight | $5–8 B/yr (freight tolls) | Port efficiency, export competitiveness, coastal corridor freed (Tier 3) | Memo 20 §2.3, 4.4 |
| Farming | Captured in water + agricultural uplift | $39–77 B/yr industry revenue: M-D drought-proofing ($6–9B), new inland ($10–20B), agrivoltaic 13.4M ha ($20–40B) | Memo 20 §3.2 |
| Cities | Captured in inland economic activation | 200+ corridor towns + 11 intersection cities; 500K–1M new dwellings; housing supply cascade (Tier 3) | Memo 20 §4.5 |
| Manufacturing | No direct SBC revenue — captured via Tier 2 tax flowback on enabled industry | Manufacturing revival $93–162 B/yr industry revenue ($28–49 B/yr Commonwealth share): aluminium, green steel, chemicals, batteries. Plus sovereign defence and export industries $55–105 B/yr ($15–32 B/yr Commonwealth share) and sovereign space industry $5–15 B/yr ($1–4 B/yr Commonwealth share) | Memo 20 §3.1, 3.6, 3.7 |
| Defence | No direct SBC revenue from defence — fuel sovereignty is the headline outcome | Fuel sovereignty retires $30–40 B/yr imported-fuel dependency. Sovereign defence manufacturing exports: $5–15 B/yr industry revenue, ~$2–5 B/yr Commonwealth share (Tier 2 — see Manufacturing row) | Memo 18, Memo 20 §3.3, 3.6 |
| Export | No standalone Tier 1 line — HVDC electricity export ($57 B/yr) is counted on the Energy row as SBC direct revenue | Industry revenue $55–105 B/yr (Tier 2): processed minerals export ($40–70 B/yr), regional grid construction ($10–20 B/yr), sovereign defence exports ($5–15 B/yr). Commonwealth share via tax flowback $15–32 B/yr. Plus regional integration cascade (Tier 3) | Memo 20 §3.6, 4.8 |
| Space | No direct SBC revenue from space — SBC enables the underlying capability | Sovereign space industry revenue $5–15 B/yr at maturity (Tier 2): Australian launch services, satellite manufacturing, earth observation, defence space contracts. Commonwealth share via tax flowback ~$1–4 B/yr | Memo 20 §3.7 |