Sun and Steel Solar’s new simplified tracker design promises Capex, EPC and O&M savings

Product outline

This tracker is based on the inventor Robert Dally’s 42 years of PV experience and 17 years of tracker experience (two previous tracker developments in 2004 & 2007 installed in 600MW of projects internationally).

It places PV modules either two in portrait (2P) or three or four in landscape (3L & 4L), which can be attached one module at a time or as pre-assembled “panels” (2 purlins + 2, 3, or 4 PV modules) that can be assembled offsite or in an on-site comfortable tent (rain or shine) for high levels of consistency (quality, reliability) and ease and speed of EPC attachment to the torque tube. These independent “panels” do not require pre-placement nor precise placement of the purlins, but allows for quick placement and simple adjustment, as needed.

There are no slippery plastic bushings at the steel-on-steel bearings, but round steel journals fitting loosely in round steel bearing races, performing as general guides to hold the torque tube in place, not as typical tight-fitting bearings requiring strict alignment, with ample friction for damping the wind, and natural electrical conduction to ground each post, all facilitating assembly, performance, and cost reduction.

The drive system consists of two 48” radius half-pulleys attached to the torque tube that are turned east and west by a redundant pair of wire cables pulled by one small size slew drive for an 8:1 leverage. All wiring is on the fixed portion of the drive system, avoiding any moving wires that must last 30+ years (~20,000 east-west cycles).

The PV modules (2P or 4L) are slightly sloped on each side to lower the centre of gravity, assist in wind tolerance, prevent sediment ponding, and lower PV operating temperature via the chimney effect.

The torque tube is round at about 10 inches in diameter to deliver the lowest kg/kW. The posts can be steel I-Beams or cold formed steel, telephone poles, or reinforced concrete piles. All steel can forego hot dip galvanisation for further savings in some environments. Each independent row holds approximately 50kW of PV and is sized ~ 4.5 meters x 60 meters. Again, where the status quo adds complexity to outdo competitive systems, our technology employs simplicity to reduce cost in material (CAPEX), construction and PV attachment (EPC), and O&M (OPEX) of the system and the weeds.  A 7-minute YouTube video of the prototype testing and CGI of the intended final product can be seen here.

Problem

Alternative trackers on today’s market add complexity in their attempt to outshine their competitors, which ultimately drives up the triple cost of CAPEX, EPC, and OPEX (30+ years of O&M).  First, they reduced the steel to lower CAPEX, then added dampers with limited effect to fight wind gallop of their flimsy structure, and now with larger and heavier modules the competition is adding drives at each post, driven by a daisy chain of spinning drive shafts; they have replaced uncomplicated steel (strong torque tube) with complicated steel (transmissions with gears and oil and seals), introducing risk.

Solution

Sun and Steel Solar’s round torque tube uses 25% less steel for the same torsional strength as other trackers’ square tubes. Its steel-on-steel bearings are natural dampers via friction, transfer the ground path to the posts, forego plastic bushings, couple the torque tube sections, have thrust stops to prevent north-south movement from terrain slopes or seismic events and have east/west limit stops to dump backside wind torque into the posts. Cost saving options include foregoing hot dip galvanizing, choosing field welded option over field bolt-together option, use of local labour content or reduction of labour in high labour cost markets, and PV modules slightly sloped for wind, a lower centre of gravity, prevention of sediment ponds, and unparalleled aesthetics. A single programmable logic controller (PLC) tracks and backtracks an immense number of rows, further reducing cost, increasing reliability, and having hardened one-way control.

Applications

This tracker serves the commercial and utility PV solar farm market. One tracker row carries about 50kW of PV; mono-facial, bi-facial, small and large format modules.

Platform

Each row is independent, with no obstructions for machinery (EPC, O&M, agricultural) to freely travel row to row (east-west) and down the aisles (north-south).

Availability

Having proceeded through prototype testing, Sun and Steel Solar is currently seeking Round A funding ($2.5 million for 25% equity) or an M&A activity to bring the product to market by Q4 2022.