Quick answer
A document describing measurable project work with units and quantities for tender pricing and cost control. Labor can be included within work-item rates; scope and measurement rules must be stated.
What Is a Solar Bill of Quantities?
Answer: A solar bill of quantities, or BOQ, describes project work in measurable items, with units and quantities that bidders can price. It supports scope comparison and cost control when used with drawings, specifications and contract terms. Labor may be included in an installed item’s rate rather than listed as separate hours. A BOQ is not automatically a complete project budget or a procurement parts list.
RICS NRM 2 is a UK reference for detailed measurement of building works. It addresses described quantities and different bill structures, including labor-only and labor-and-material items. Use the measurement rules specified by the project; RICS conventions are not a universal solar tender requirement.
A bill of materials identifies selected components for procurement. A BOQ identifies and measures the work to be priced. Some organizations use the terms differently, so define what each deliverable covers.
Measure Work, Not Just Parts
A BOQ item should make its boundary understandable. For example, “supply and install modules” is different from “supply modules only.” State what the rate includes, what it excludes, the measurement unit and the design revision used for the quantity.
| Solar work section | Example measurement basis | Scope question to resolve |
|---|---|---|
| DC array | Module count or specified capacity | Supply only, installation, handling and connection inclusions |
| Racking | Defined assembly or measured work | Attachments, flashing, access and structural requirements |
| Electrical routes | Measured conductor, containment or trench quantities | Multiple conductors, fittings, termination and reinstatement scope |
| Conversion equipment | Specified equipment or complete assembly | Accessories, mounting and connection work |
| Monitoring | Defined equipment and installation scope | Communication, configuration and any ongoing services |
| Commissioning | Defined tests and deliverables | Responsible personnel, procedures and acceptance records |
| Permitting/design | Agreed services or allowances | Fees, professional review and revision responsibilities |
The same route can require separate quantities for trench length, containment and individual conductors. Avoid pricing all three as the same unexplained number. Distinguish net measured work from purchase packs, stock lengths and agreed allowances.
Useful Line-Item Fields
Record the item identifier, clear description, unit, measured quantity, unit rate where priced, line amount and drawing/specification reference. Add currency, rate date, stated inclusions, exclusions and quantity status where needed.
Keep firm quantities, estimated quantities and unresolved scope distinguishable. An empty cell is not necessarily zero cost. Agree how allowances, taxes, freight, preliminaries, overhead, profit and risk are handled rather than assuming the sum of one materials worksheet includes them all.
An elemental view can group work by DC array, AC connection or civil works. A trade or work-package view may suit the tender instead. A material schedule and a labor-resource estimate can support the BOQ without becoming mandatory BOQ formats themselves.
Illustrative Unit-Rate Arithmetic
Suppose a tender item is explicitly defined as supply and install 25 modules, each rated 400 W, with a hypothetical composite rate of $250 per module including the stated material and installation scope:
25 × 400 W = 10,000 W = 10 kW DC nameplate capacity.
25 × $250 = $6,250 for that defined work item.
These are illustrative assumptions, not verified market prices. The $6,250 is not a complete installed-system price. If the composite rate includes module-installation labor, adding that labor again in another line would double count it. Alternatively, a supply-only rate and a separately described installation line can be used if that is the agreed pricing structure.
For a separate quantity-control example, assume a wire takeoff of 150 ft and comparable installed use of 190 ft:
190 − 150 = 40 ft additional use; 40 / 150 × 100 = 26.67% above the takeoff.
Investigate actual routing, conductor count, field changes and allowance treatment. This difference does not establish a universal contingency percentage, approved design or supplier ordering quantity.
Comparing Bids Without Hiding Scope
Send bidders the same current drawings, specifications and measured scope. Request clarification of exclusions, substitutions, provisional amounts and rate inclusions. A standardized form helps comparison but does not guarantee identical interpretations or prevent a dispute.
Check whether bidder totals include the same work. A lower total may exclude trench reinstatement, equipment accessories or a required review. Conversely, do not assume a more detailed list is automatically more accurate than a reviewed lump-sum estimate.
For progress payment and changes, follow the actual contract’s measurement, valuation and approval procedures. A completed BOQ section does not automatically entitle the contractor to payment. Keep the original quantity, revised quantity, reason, supporting drawing and agreed valuation traceable.
Building and Reviewing the Solar BOQ
Designers and estimators: establish the design revision, measurement method and units before takeoff. Use actual routes, specified equipment and structural information. Do not infer all cable, clamp or attachment quantities from module count.
Installation teams: compare takeoff quantities with verified installed work and explain deviations. Distinguish authorized scope changes from unused procurement stock or waste. Keep the installed record aligned with as-built drawings.
Sales and project managers: present an understandable summary without hiding exclusions. Validate cost inputs, supplier validity and estimated labor assumptions before using them in project financial modeling. A BOQ does not by itself establish production, payback or cash flow.
Software can support modeled quantity extraction, but unmodeled site work and uncertain scope still need review. Confirm the units, item inclusions and supported output fields in a SurgePV demo rather than assuming complete automated labor, cable or structural takeoff.
Frequently Asked Questions
How is a BOQ different from a BOM?
A BOM focuses on selected parts for purchasing and staging. A BOQ focuses on described and measured work for pricing. They can overlap, but their scope and units must be stated.
Must a BOQ list separate labor hours?
No. Labor can be included in a composite installed-work rate or priced separately according to the agreed method. Do not add a separate labor charge for work already included in another rate.
Does the total of the BOQ equal the whole project budget?
Only if the defined scope and pricing structure cover the relevant costs. Identify exclusions, allowances, taxes and other project costs, and use the actual contract and budgeting requirements.
Can design software produce every BOQ quantity?
It can support quantities represented by its model and inputs. Verify coverage, units and calculations, and review field-dependent, electrical, structural and unmodeled work separately.
Related Glossary Terms
About the Contributors
CEO & Co-Founder · SurgePV
Keyur Rakholiya is identified by SurgePV as its CEO and a company co-founder. His SurgePV author page lists only role information that can be tied to the public profile below; credentials, project totals, testing claims, media appearances, and speaking engagements are not asserted without retained evidence.
Editorial contributor · SurgePV
Rainer Neumann is credited as an editorial contributor on SurgePV content. This profile does not assert engineering credentials, project totals, software-testing experience, education, speaking engagements, or media citations because independent verification evidence is not retained in the publication record.
