Most lost margin on a solar EPC contract was locked in on the day the bid went out. A cable run priced from a sketch, a yield number taken from a brochure, a missed grid clause.
None of these show up until the project is already signed. This solar EPC bid checklist gives the engineering team a fixed set of checks to clear before commercial sets the price.
Quick answer. A solar EPC bid checklist should confirm seven things before pricing: site data and constraints, an energy yield with stated loss assumptions, a layout that fits the site, a bill of quantities taken from that layout, a grid connection path, a structural and civil basis, and current procurement rules such as ALMM in India. Each item needs evidence, an owner, and a go or no-go decision.
TL;DR
- Run 40 checks in 7 groups. Any open item becomes a priced risk or a written exclusion.
- Take quantities from a layout, never from a per-MW ratio alone.
- State every yield assumption. A P50 without a loss table cannot be defended.
- Confirm module and cell sourcing rules on the bid date. In India, ALMM List-II for cells has applied since June 1, 2026, with set exemptions.
This page is a working checklist, not a comparison. If you need to decide how much engineering to buy at bid stage versus after award, read bid-stage vs IFC-stage engineering first. If you are hiring a design vendor, our solar design RFP guide covers that side.
How to use this solar EPC bid checklist
Give each check one of three statuses:
- Closed: evidence is on file and the number is in the price.
- Priced risk: the item is open, and a contingency covers it.
- Excluded: the item is open, and the bid states it is not included.
Anything still blank on bid day is a hidden cost. Log the evidence (file name, date, source) next to each check so the post-award team inherits it.
Group 1: Site data and constraints (6 checks)
| # | Check | Evidence | No-go if |
|---|---|---|---|
| 1 | Boundary and usable area confirmed | Survey, KMZ, or owner drawing | Area depends on unverified land |
| 2 | Shading objects and horizon recorded | Site photos, horizon profile | No site visit and dense obstructions |
| 3 | Roof or ground condition known | Structural drawings, soil data | Roof age or soil type unknown on a large job |
| 4 | Access and laydown confirmed | Site visit notes | Crane or truck access unclear |
| 5 | Setbacks and restricted zones mapped | Local rules, fire code, owner limits | Layout ignores required setbacks |
| 6 | Water source for cleaning noted | Owner confirmation | O&M scope depends on it and it is unknown |
A desktop study can close several of these early. Our desktop feasibility method shows where it works and where it does not. When the site is large or unclear, a site survey and feasibility study is cheaper than a wrong bid.
Group 2: Energy yield and performance (6 checks)
| # | Check | Evidence | No-go if |
|---|---|---|---|
| 7 | Weather data source named | Meteonorm, Solargis, NSRDB file | Source not stated |
| 8 | Loss table complete | Soiling, temperature, mismatch, wiring, availability | Losses entered as one lump figure |
| 9 | Near shading modelled | 3D scene or shading report | Large obstructions not modelled |
| 10 | P50 and P90 stated if a guarantee is offered | Yield report | Guarantee based on P50 only |
| 11 | DC/AC ratio justified | Clipping loss result | Ratio copied from a past job |
| 12 | Degradation assumption stated | Module datasheet, warranty | Guarantee period longer than the modelled period |
If the contract carries a performance guarantee, check 10 matters most. A P90 value tells you what output is exceeded in 90 percent of years. Build quality matters too. The Raptor Maps 2026 Global Solar Report found 4.46 percent average power loss at commissioning inspections. A bid yield that assumes a perfect build is optimistic.
Our P50 and P90 explainer covers how to read them.
Group 3: Layout and electrical design (7 checks)
| # | Check | Evidence | No-go if |
|---|---|---|---|
| 13 | Layout drawn on the real site | Bid layout drawing | Capacity based on area times a ratio |
| 14 | Row spacing or tilt fixed | Shading study | Spacing not tested against winter sun |
| 15 | String size checked at site minimum temperature | String sizing sheet | Voc not checked against inverter limit |
| 16 | Inverter type and count fixed | Single-line diagram (draft) | Inverter not yet chosen |
| 17 | Cable routes drawn | Route sketch with lengths | Lengths estimated without a route |
| 18 | Voltage drop checked on long runs | Cable calculation | Long runs not checked |
| 19 | Earthing and lightning protection scoped | Scope note | Not mentioned in scope |
Group 4: Bill of quantities (6 checks)
| # | Check | Evidence | No-go if |
|---|---|---|---|
| 20 | Every BOQ line linked to the layout | BOQ with drawing references | Quantities from a per-MW ratio only |
| 21 | DC and AC cable lengths taken from routes | Cable schedule | Cable is a lump sum |
| 22 | Structure tonnage from a preliminary design | Structural estimate | Tonnage copied from another site |
| 23 | Spares and wastage stated | BOQ notes | No allowance shown |
| 24 | Civil items listed | Foundations, trenches, roads, fencing | Civil left as one line |
| 25 | Supplier quotes dated | Quote file | Quotes older than the validity period |
Cable is where bid BOQs most often go wrong, because lengths depend on routes that do not exist yet. Our guide on cable mis-costing in solar BOQs covers this. For method, see how to calculate a solar BOQ.
Group 5: Grid connection (5 checks)
| # | Check | Evidence | No-go if |
|---|---|---|---|
| 26 | Connection voltage and point confirmed | Utility or DISCOM letter, owner data | Voltage assumed |
| 27 | Applicable grid standard named | Regulation or utility manual | Standard not identified |
| 28 | Metering arrangement known | Tariff or regulation | Net metering assumed without checking the cap |
| 29 | Substation or transformer scope clear | Scope split | Unclear who builds it |
| 30 | Approval timeline in the schedule | Utility process note | Schedule ignores approvals |
In India, the Central Electricity Authority sets the grid connection rules in the Technical Standards for Connectivity to the Grid Regulations, amended in 2019. The current text is on the CEA regulations page. For rooftop and C&I projects, check the state DISCOM process and caps too.
Group 6: Structural and civil basis (5 checks)
| # | Check | Evidence | No-go if |
|---|---|---|---|
| 31 | Design code and edition named | IS 875, ASCE 7 edition | Code edition not stated |
| 32 | Wind and snow inputs set for the site | Basic wind speed, exposure, terrain | Values from another region |
| 33 | Roof capacity checked (rooftop) | Existing drawings or assessment | No check on a weak or old roof |
| 34 | Foundation type assumed and stated (ground mount) | Soil data or stated assumption | Piles priced without soil data and no exclusion |
| 35 | Drainage and flood risk noted | Site data | Low-lying site not reviewed |
Use the code edition the local authority enforces. For US projects, our ASCE 7 adoption guide shows how this varies.
Group 7: Compliance and procurement (5 checks)
| # | Check | Evidence | No-go if |
|---|---|---|---|
| 36 | Module and cell sourcing rule confirmed | ALMM list check, tender clause | Rule not checked on the bid date |
| 37 | Domestic content needs checked (if any) | Tender or scheme terms | DCR terms missed |
| 38 | Permits and approvals listed | Permit list | No list |
| 39 | Owner technical specification reviewed | Marked-up spec | Spec not read line by line |
| 40 | Exclusions and assumptions written | Bid cover letter | No exclusions list |
India’s Ministry of New and Renewable Energy (MNRE) keeps the Approved List of Models and Manufacturers (ALMM). List-I covers modules and List-II covers cells. The lists are on the MNRE ALMM page.
List-II has applied since June 1, 2026. MNRE issued a clarification in August 2026, reported by Renewable Watch (2026). It kept exemptions for some bids submitted by August 31, 2025. It also exempted net metering and open access projects commissioned by December 31, 2026. Check the current MNRE order for your project. Our ALMM List-II deadline guide has more detail.
What should the bid engineering file contain?
At the end of the checklist, the file handed to commercial should hold:
- The bid layout drawing and capacity summary.
- The yield report with its loss table.
- The BOQ, with each line referenced to a drawing.
- A draft single-line diagram.
- The structural and civil basis note.
- The risk register: every “priced risk” item with its contingency.
- The exclusions list, copied into the bid cover letter.
This file is also the starting point after award. When it is complete, the detailed design team does not have to rebuild the basis from scratch.
Common bid-stage mistakes
- Pricing from per-MW ratios. Ratios are fine for a budget estimate. They are not a bid.
- One yield number with no losses. Clients and lenders will ask how you got it.
- Silent assumptions. An assumption that is not written down is a free scope item for the client.
- Old supplier quotes. Module and cable prices move. Date every quote.
- Reading the owner spec too late. Specs often name brands, tests, or documents that change cost.
FAQ
How long does bid-stage engineering take?
It depends on size, data quality, and how many checks are already closed. Agree a date with the design team when the bid is accepted for review, not the day before submission.
Do I need PVsyst at bid stage?
You need a yield model with stated losses. PVsyst is common for lender-facing work. For smaller jobs a simpler tool may do, as long as the assumptions are written down.
What is the difference between this checklist and IFC drawings?
This checklist sets the basis for a price. Issued-for-construction (IFC) drawings come after award and are detailed enough to build from.
Should exclusions go in the bid?
Yes. Every open item that you do not price should be listed as an exclusion in the bid cover letter.
Clear the checklist before the price leaves the building
A bid is only as sound as its weakest assumption. Run the 40 checks, log the evidence, and turn every open item into a priced risk or a written exclusion.
Our Solar 3D Pre-Design service covers bid-stage layouts, shading analysis, energy estimates, and proposal support. To see the format, download our design samples. For a specific tender, send us the project details and we reply within 1 business day.