Solar Feasibility Brief: What to Decide Before Producing a Full Proposal

A solar feasibility brief answers a narrower question than a proposal: is there enough evidence and potential value to justify the next piece of project work? That question matters because a fast first response can be helpful without pretending that a site has already been surveyed, an electrical arrangement verified, or a customer’s financial position confirmed.

For installers and EPCs, the brief is an antidote to two costly habits. The first is investing full design effort before the customer, site, and objective are sufficiently understood. The second is sending an attractive early scenario that a buyer or colleague reads as a complete commitment. A well-written brief makes both the opportunity and the uncertainty legible.

Give the Brief One Job

The brief should not become a miniature project file. Its job is to guide a next decision: schedule a site survey, request better consumption data, prepare one or more proposal options, pause the opportunity, or route a specialist question. State that job near the top.

For example, a commercial brief might ask: “Does the available roof area and customer load information justify a detailed consumption review and survey?” A residential brief might ask: “Is there enough preliminary site and bill information to prepare an indicative customer option?” These questions are more useful than a generic status such as “qualified.” They tell the reader what the current evidence can support.

The U.S. Department of Energy’s Solar Energy Technologies Office describes a broad field of solar technology and deployment. Public context is valuable, but it cannot answer a project’s property, utility, price, or approval questions. A feasibility brief must identify the actual project material it uses.

Begin With the Customer’s Decision

Customer goals vary. Some want to explore bill reduction; others need to assess a facility investment, prepare a budget, respond to a sustainability target, consider resilience, or understand whether a property can host PV at all. A feasibility brief should repeat the goal in the customer’s terms, then identify the decision the team expects them to make next.

This avoids a common mismatch: the team optimises for maximum array size while the buyer is trying to understand capital planning, construction timing, or a narrow consumption problem. The early scenario can still illustrate potential capacity, but its role is tied to the stated job. If the customer has not said what they are deciding, that gap itself belongs in the brief.

Include known stakeholders and decision dates when relevant. A facilities manager may need a landlord conversation. A homeowner may need to compare payment paths. A commercial buyer may need current load data for an internal review. Those are not sales objections to hide; they are the route through the opportunity.

Distinguish Evidence From Convenient Inputs

Early solar work commonly draws on an address, public imagery, a bill, a customer description, and a request for a particular system size. Each can be valuable. Each has limits. The brief should list the source and date, then say whether it is adequate for the next decision.

Use the phrase “customer-provided,” “publicly available,” “preliminary,” or “to be verified” where it helps. Such labels are not legal decoration. They tell the next reader which question should be asked before a preliminary figure becomes an order, permit, or field instruction.

Show an Indicative Scenario Without False Precision

An early scenario can be useful when it is plainly labeled. The scenario may describe a possible configuration range, relevant roof or ground area, an approximate consumption relationship, and preliminary production or financial inputs. It should also name the variables most likely to alter the result.

NREL presents PVWatts as a tool for estimating the energy production and value of grid-connected PV. An estimate is only as interpretable as the inputs and conditions that accompany it. A feasibility brief should therefore say which consumption, layout, weather, shading, tariff, export, or financing assumptions underlie any illustration it presents.

Avoid decorative precision. A screening range is usually more honest than a number stated to unnecessary decimal places. If the system concept depends on unverified roof dimensions or service details, name that dependency before the customer begins to treat the first output as a fixed scope.

Put Constraints Where the Next Team Will See Them

Early constraints do not all require resolution immediately. They do require a route. List conditions that could change whether the project proceeds, its configuration, timing, price, projected result, or approval path. Examples can include roof works, access, tenancy, electrical capacity, unusual consumption changes, utility rules, equipment lead times, and construction restrictions.

For each material item, explain its consequence and next step. “Customer reports roof works next year; clarify schedule before full proposal because array removal or sequencing may affect scope” is useful. “Roof issue” is not. If several items are active, link the brief to a solar project constraint register so the project maintains one live source of ownership and closure evidence.

The brief is also the right place to decide whether the opportunity should be escalated. Questions involving structural suitability, safety, code, utility requirements, property authority, or other specialised matters should go to the appropriate professional or local process. An early commercial document does not settle them.

Recommend One Next Step, Not Ten

A good brief ends with a clear recommendation. It may be “request twelve months of bills and schedule a survey,” “prepare two commercial options using the stated assumptions,” “hold design until the customer confirms roof works,” or “route service questions for technical review.” The recommendation should follow from the evidence rather than from a desire to keep every lead moving.

Name the owner and the information required. If a customer must supply a document, say why it matters. If a survey is recommended, identify the questions it will answer. That makes the request easier to accept and lets sales follow up with a purpose rather than a generic reminder.

There is value in a documented decision not to proceed yet. If the current evidence cannot support a useful next action, record what would reopen the opportunity. This preserves trust and prevents a team from repeatedly rebuilding a design around the same missing input.

Keep the Brief Separate From the Proposal

The line between feasibility and proposal is not always a date. It is the intended decision and level of commitment. A feasibility brief may include a possible system range and explain why a survey is worthwhile. A proposal presents a customer option with its stated scope, assumptions, terms, and next action. Neither should be confused with a construction, procurement, permit, or engineering release unless it meets that separate purpose.

When the project advances, bring key facts forward rather than copying the brief unchanged. Update the consumption source, site evidence, configuration, financial assumptions, and exclusions. Mark the early document as superseded where it no longer reflects the current story. Solar Proposals can help teams present a customer-facing option; the feasibility brief remains the decision record that explains why the team moved from screening to proposal work.

Use a Repeatable Format With Room for Exceptions

A lightweight structure keeps quality consistent without forcing every project into the same answer:

1. decision being considered and customer objective;
2. site, consumption, and commercial evidence received;
3. indicative configuration or opportunity statement;
4. material assumptions and known constraints;
5. information gaps and their impact;
6. recommended next action, owner, and target date; and
7. revision date and link to related project records.

Add a short plain-language summary for customer use if the brief will be shared. Internal readers may need more detail about source quality and ownership. The customer summary should describe the opportunity and next verification step without presenting uncertain outputs as fixed facts.

Check for Cannibalisation in Your Own Process

Sometimes a “feasibility” request is actually a request for an existing product or service conversation. Before creating a new document, check whether the customer has already received an option, whether the sales record contains a more current bill, or whether a designer is already investigating the same condition. The brief should consolidate current facts, not create parallel project narratives.

Likewise, do not use the brief as a substitute for a decision log. If a buyer chooses between options, record the decision and its reason in the appropriate project record. If a technical condition changes the configuration, update the revision basis. The brief is the early gateway; it should point to later controls rather than compete with them.

A Practical Review Before Sending

Ask these questions before sharing a brief internally or externally:

1. Can the reader tell what decision this document supports?
2. Does every material number have an identifiable basis?
3. Are the largest unknowns visible in plain language?
4. Is the recommended next step proportionate to the evidence?
5. Could anyone mistake this for a final price, technical release, or project guarantee?

If the last answer is yes, change the title, summary, and labels. The objective is not to make the opportunity appear less attractive. It is to ensure that the prospect and the delivery team understand what has actually been assessed.

Build Better Intake From Repeated Briefs

After several briefs, look for the same missing information. Perhaps bills are often incomplete, roof works are discovered late, consumption changes are not discussed, or utility tariff information arrives only after a proposal is built. Those patterns are evidence for improving intake questions, not a reason to add boilerplate to every proposal.

Ask the people doing surveys, design, and delivery which early assumptions create rework. Then modify the feasibility brief and lead intake so that those conditions are requested earlier. The outcome is a more useful first conversation, not merely a longer form.

Frequently Asked Questions

What is a solar feasibility brief?

It is a short, evidence-led record used to decide whether a solar opportunity should progress to survey, detailed design, proposal, or another next step. It records the available information and boundaries of an early scenario.

How long should a feasibility brief be?

It should be long enough to make the next decision clear and no longer. A concise record with source dates, key assumptions, constraints, and a defined action is usually more useful than a large report that hides the decision.

Can a customer receive the brief?

Yes, when it is written in clear language and visibly distinguishes indicative screening information from a proposal or technical release. Remove or explain internal ownership notes as appropriate to the conversation.

What happens after feasibility is positive?

The team should request the evidence or review needed for the next stage, then create a proposal or technical package using current inputs and stated assumptions. Do not simply relabel the early brief as a final design.