AI tendering for solar PV and renewables installers

Price a solar PV tender from a system design: panel layout from the roof drawings, inverter, mounting for that roof type, labour days and the DNO application. Anything above 16 A per phase (3.68 kW single phase) needs G99 approval before it can connect, so the DNO often sets the programme. Keep pricing time low, because win rates are poor.

What makes solar tenders hard to win and price?

Lots of bidders, uncertain connections and roofs nobody has checked. A commercial PV tender can come with a roof plan, a target kWp and a request for yield figures, but no structural survey and no word from the DNO.

The problems that come up on most solar and battery tenders:

• System design and yield. Panel layout, orientation, shading and inverter sizing, with a yield figure the client will hold you to.
• DNO applications. G98 or G99, export limits, and approval timescales you don't control.
• Roof surveys and structural checks. Whether the roof can take the load, and what the mounting fixes into.
• Access. Scaffold, edge protection and roof-top working on occupied buildings.
• Certification. MCS, which the client needs for Smart Export Guarantee payments.
• Low win rates. Many installers pricing the same job.

That's how he described solar firms tendering, and it's the reason to keep each tender quick. The same firm went on to win an 11-job solar contract: one tender, eleven installs, which is the kind of work worth a full pricing effort.

How do you price a 50 kWp commercial roof array?

Lay out the panels on the roof drawing, price the kit and labour, then add the structural check and the DNO application as their own lines.

The structural check is £850, under 3% of the price. Skip it, and a roof that can't take the load turns a £5,158 margin into a redesign or a walk-away. Qualify the price as subject to the engineer's report if the client won't pay for a check before tender.

Does this system need G99 approval from the DNO?

If it's above 16 A per phase, yes. That's 3.68 kW on a single phase. Count all generation on the site, and ask the DNO how any battery storage is counted.

These rules apply across Great Britain, through whichever DNO covers the site. In Northern Ireland, check the connection process with NIE Networks before you price.

If the client wants Smart Export Guarantee payments, MCS says the installation must be MCS certified and have a registered smart meter recording export. That covers systems up to 50 kW, the limit of MCS's scope. The 50.4 kWp example above is just over it, so for SEG the client needs the installation certified another way, and Ofgem leaves it to the SEG licensee to say what evidence it accepts. Check with the client's chosen licensee before you promise SEG on anything over 50 kW.

What should a solar tender qualify?

The DNO, the roof, access and export. These four decide whether the system gets built as priced.

Tender: project, kWp solar PV and battery installation
Our price: £amount excluding VAT, dated date

DNO approval
1. System design to G98 / G99. Price and programme subject to the DNO's approval and connection offer. Any DNO conditions, network reinforcement or connection charges are excluded.
2. If the DNO sets an export limit below x kW, the design will be revised and revalued. An export limitation device is included / excluded.

Roof and structure
3. Price subject to a structural engineer's confirmation that the roof can take x kg/m² plus wind loads. Strengthening works excluded.
4. Roof assumed sound and watertight. Repairs to sheets, fixings or rooflights found during installation are a variation.

Access
5. Scaffold, edge protection, loading bay and roof access by others, erected and inspected before we start.
6. Price based on number days of continuous roof working in suitable weather.

Performance and certification
7. Estimated yield is a calculation, not a guarantee. Shading from future buildings or plant excluded.
8. Installation by an MCS certified installer: included / not required.

Electrical
9. Connection to the existing board / switchgear assumed with spare capacity. Upgrades to the incoming supply or switchgear excluded.

Use the tender qualifications and exclusions template for payment, price validity and attendances.

What can AI do on a solar tender, and what can't it?

AI speeds up the parts that make solar tendering a time sink. It can't climb the roof or speak for the DNO.

What AI does well:

• Lays out the array from a roof plan, avoiding rooflights, edges and plant, and gives a panel count and kWp. See can AI do a take-off from drawings.
• Reads the pack for kWp targets, yield requirements, export expectations and roof information.
• Flags G98 or G99 from the system size and drafts the DNO application information.
• Checks the spec for kit that clashes: an inverter too small for the array, or mounting not suited to the roof type.
• Drafts qualifications with the DNO, roof and access lines filled in.

What still needs the installer:

• The roof. Condition, fixings, and whether it's worth putting panels on at all.
• Buildability. Cable routes, inverter location and isolation on an occupied site.
• Risk. How much DNO and structural uncertainty to price in.
• The decision on whether this tender is one of the one-in-twenty worth chasing.

What does each won solar tender cost you?

At one win in twenty, a lot. Divide the cost of pricing one tender by your win rate.

At ten hours a tender, £50 an hour and a 5% win rate, each win costs £10,000 of pricing time, and forty tenders a year cost £20,000. Cutting the hours per tender, or bidding fewer jobs you're more likely to win, does more for profit than any discount. See what's a normal quote win rate and use the 10-minute tender read to bid less and win more.

Solar is electrical work at heart; see how Nexley handles it on the electrical trade page.

Common questions