Solar Mounting Structure Cost per kW and per MW in India, 2026

What the structure line item covers

In an Indian EPC bill of quantities the module mounting structure (MMS) covers the steel members that carry the modules: columns or posts, rafters, purlins, bracing, module clamps and fasteners. Depending on the contract it may also include foundations, transport, installation and the design report. Prices only compare when scope is identical, so fix what is in and out first.

Structure and foundation together are typically [8 to 14 per cent] of EPC cost on a utility-scale plant and [4 to 8 per cent] on an industrial metal-sheet rooftop, where the existing purlins carry most of the load.

Indicative cost ranges, 2026

The ranges below are supply-only, ex-works, for cold-formed GI steel structures with SS304 or hot-dip galvanised fasteners, sized for 550 to 620 Wp modules in a wind zone of 44 m/s under IS 875 Part 3. Foundations, installation, transport and GST are excluded.

Fabricated GI structure sells for roughly [Rs 80 to 110 per kg] delivered in 2026, so steel weight per MW multiplied by that rate should land inside the cost column. A quote far below that figure usually means understated weight or lighter sections and coating.

What drives the cost

Steel weight per MW

Weight is the single largest driver. It is set by module size, rows per table (1P, 2P or 4L), span between posts, tilt angle, ground clearance, and the design wind pressure. A 2P table at [3.0 to 3.5 m] post spacing in a 39 m/s zone is at the light end; the same table with [4.5 m] spans in a 50 m/s cyclonic zone needs thicker C and Z sections and more bracing.

Coating

Pre-galvanised coil to IS 277 with a 275 g/m² zinc class (Z275, about 20 microns per side) is the standard for cold-formed solar sections. Moving to a 350 g/m² class adds [3 to 5 per cent] to steel cost. Hot-dip galvanising after fabrication to IS 4759 or ISO 1461 (55 to 85 microns depending on thickness) adds [Rs 14 to 22 per kg] plus handling, and is normally reserved for posts, heavy rafters and coastal sites.

Wind zone

IS 875 Part 3 sets basic wind speeds from 33 to 55 m/s. Wind pressure rises with the square of speed, so a 50 m/s site carries 64 per cent more pressure than a 39 m/s site. Steel weight rises less than proportionally because some members are governed by minimum thickness, but a move from 39 to 50 m/s typically adds [25 to 35 per cent] to weight and cost. Coastal sites in the cyclonic belt also attract the k4 factor of 1.15 for industrial structures, a further 32 per cent in pressure.

Foundation type

Ground-mount foundations are quoted separately. Driven or rammed piles are the cheapest where soil allows, at roughly [Rs 2,500 to 4,500 per pile]. Cast-in-situ RCC piers to IS 456 cost more and slow the programme. Helical or screw piles suit rocky or high-water-table sites and are priced at [Rs 5,000 to 9,000 each]. Rooftop RCC ballast at [60 to 120 kg per square metre of array] is cheap in material but heavy on the slab; chemical anchors avoid the ballast but need a roof waterproofing detail.

Logistics and site

Cold-formed sections nest and ship well: a 1 MW ground-mount kit is around [3 to 4 truckloads] of 20 t each. Freight from Hyderabad to a site 500 km away adds roughly [Rs 1.5 to 2.5 lakh per MW]. Sites without crane access, sloped terrain and short table lengths all raise cost above the table ranges.

Rooftop: metal sheet versus RCC

On a metal-sheet industrial roof the modules are laid close to the roof pitch on short rails or brackets fixed through the sheet to the purlins, so steel per MW is a fraction of a ground mount. The engineering cost is in checking that the existing purlins and their connections can take the added uplift; a purlin designed to IS 800 for sheet load alone may need strengthening at [Rs 200 to 600 per kW].

On an RCC roof the structure must generate its own tilt and its own holding-down. Low-rise systems at 10 to 15 degrees use ballast or anchors. Elevated systems with 2 to 3 m columns, which keep the roof usable, are two to three times heavier and need the building engineer to confirm beam capacity.

Ground mount

Fixed-tilt tables on driven piles are the reference case. Cost per MW falls with project size through bulk coil purchasing and repetitive fabrication, not lighter design; [10 to 15 per cent] between a 5 MW and a 50 MW order is typical. Pile-pull-out testing, normally [1 to 2 per cent] of piles loaded to [1.5 times] design uplift, is a small cost that should be in every ground-mount scope.

Carport

Carports carry the same module load on columns 2.5 to 4 m tall with clear spans between vehicles. The cantilever or portal frame is hot-rolled or built-up, and steel per MW is two to three times a ground mount. Foundations are RCC pads or piles with moment capacity at [Rs 15,000 to 40,000 per column]. Gutters, lighting and cable routing should be listed as separate items.

How to compare quotes

1. Normalise to Rs per kWp DC using the same module model and count for every bidder.
2. Ask for structure weight in kg per MW and the section thicknesses used. Compare weight-times-rate against the quoted price.
3. Confirm the coating specification: IS 277 zinc class in g/m² for pre-galvanised, or IS 4759 or ISO 1461 with microns for hot-dip.
4. Confirm the design basis: IS 875 Part 3 year, basic wind speed, terrain category, k-factors and tilt. A structure designed for 39 m/s cannot be moved to a 47 m/s site.
5. Confirm fastener material and grade: SS304 to ASTM F593 or A2-70, or hot-dip galvanised 8.8 to IS 1367.
6. List exclusions: foundations, installation, transport, unloading, pull-out tests, design report and GST. [Check whether GST has been assumed at the concessional solar rate or at 18 per cent as structural steel.]
7. Ask for the warranty period on coating and structure separately, and the deflection limit adopted from IS 800.

About Vasistron

Greentek Vasistron Private Limited manufactures solar mounting structures at Dhulapally, Hyderabad. The SolBase Terra ground mount, SolBase Aero carport and canopy, and SolBase Tecta rooftop and shed systems use GI cold-rolled C, Z and U sections with SS304 fasteners, assembled without site welding, and are designed to IS 875 Part 3 for the wind zone of each project.