Two standard MMC pylons spaced 12–15 m apart, structurally coupled by three captured cross-beams. High-voltage strain towers, river crossings, and heavy conductor loading up to ±1100 kV UHVDC. Used as intermittent strain towers along an otherwise-TB line.
Per-tower cost is split into three layers: Structure (foundation, pylon, tubular, cross-arm), Services (tower-mounted equipment for the transmission service), and Install (all field labour and plant). Total per tower is the sum of the three; per-km figures shown at 100 m typical transmission spacing (10 towers per kilometre). Actual deployment density varies with voltage and terrain.
Foundation, pylon column, tubular tension element, cross-arm, and captured cross-beams. Module costs are Megafactory pour rate + Hub and die allocation at moderate platform utilisation (~$310/module). Pre-feasibility grade, ±30%.
| Item | Per tower (AUD) | Per-km (AUD) |
|---|---|---|
| Cutter heads (sacrificial hybrid, 2 per tower — 1 per leg) | $20,000 | $200,000 |
| Caisson ring segments (precast concrete) — 30 rings (15 per leg × 2 legs, 15 m depth) | $20,550 | $205,500 |
| Caisson anchor caps (2 per tower) | $1,870 | $18,700 |
| Pile caps / base slabs (2 per tower) | $1,870 | $18,700 |
| Pressure grout (2 caissons × 2 m³) | $1,600 | $16,000 |
| Tubulars — 2 × 20″ × 171 ppf L80 13Cr API 5CT, ~17 m each | $24,480 | $244,800 |
| Column segments (precast concrete, 12 tapered — 6 per leg) | $9,120 | $91,200 |
| Captured cross-beam modules (3 × complex P#7 + steel rib) | $5,850 | $58,500 |
| Cross-beam-to-column saddle hardware (6 saddles) | $2,400 | $24,000 |
| Structure subtotal | $87,740 | $877,400 |
Tower-mounted equipment for the transmission service. The conductors themselves are catalogued on the HVDC Transmission service page and added to deployment cost.
| Item | Per tower (AUD) | Per-km (AUD) |
|---|---|---|
| Conductor attachment hardware (3 bipoles × insulator string sets) | $7,500 | $75,000 |
| Fibre optic OPGW attachment fittings | $800 | $8,000 |
| Aviation lights + earthing + bonding | $2,000 | $20,000 |
| Anti-climb, signage, access | $1,500 | $15,000 |
| Services subtotal | $11,800 | $118,000 |
All field labour and plant required to deploy the tower and string the conductors. Drilling rig service charged at ~$1,200/hour all-in. Includes site access, survey, easement and permits, and project management allocation per tower.
| Item | Per tower (AUD) | Per-km (AUD) |
|---|---|---|
| Foundation drilling (SBC dual rig, 8 hrs × 2 caissons × $1,200) | $19,200 | $192,000 |
| Pylon segment erection (12 segs both legs + 2 tubulars + tensioning) | $8,500 | $85,000 |
| Cross-beam placement (3 captured beams) | $5,000 | $50,000 |
| Conductor stringing (3 bipoles allocated) | $15,000 | $150,000 |
| Earthing, OPGW, lighting install | $3,500 | $35,000 |
| Site access + survey | $4,000 | $40,000 |
| Easement + permits | $4,000 | $40,000 |
| Project management + supervision | $6,000 | $60,000 |
| QA, commissioning, energisation | $3,000 | $30,000 |
| Install subtotal | $68,200 | $682,000 |
Structure + Services + Install. Conductor cable itself catalogued separately on the HVDC Transmission service page; deployment cost = tower cost + conductor per-km. At 100 m typical transmission spacing this works out to 10 towers per kilometre.
Pre-feasibility grade, ±30%. Modules costed at Megafactory pour rates from Memo 2 (Megafactory Economics) plus moderate-utilisation Hub and die allocation (~$310/module). Install rates are pre-feasibility benchmarks against light civil construction at corridor scale. All figures AUD.
MMC-TA is a strain tower deployed intermittently along an otherwise-TB line — typically every few kilometres or at terrain crossings. The per-km cost shown at 100 m spacing is the catalogue reference rate for direct comparison; actual deployment density is much lower, so the effective contribution to total corridor cost is correspondingly smaller.