Solar Procurement Checklist: 9 Checks Before You Sign the Quote

Solar Procurement Checklist: 9 Checks Before You Sign the Quote

I've handled solar procurement and residential retrofit orders for 9 years. I've personally made and documented 7 significant mistakes, totaling roughly $18,400 in wasted budget. Now I maintain our team's pre-check list to prevent others from repeating my errors.

Use this if you're comparing utility-scale First Solar modules for a power plant, sizing a home array, buying a solar portable power station, or scheduling an EV charger installation in Indian Head Park. It's built for people who want the quote to survive contact with permits, load calculations, and warranty fine print. There are 9 steps.

One quick vocabulary check: if you searched 'first planet solar system,' that's Mercury—not a module vendor. I only mention it because search typos have sent people to the wrong First Solar datasheet before.

Step 1: Write the scope before you compare prices

Most bad solar comparisons start with a $/W number and no scope. Utility-scale First Solar Series 6 or Series 7 modules, an 8 kW home array, a 1 kWh portable power station, and a 48A EV charger are not the same purchase.

From the outside, it looks like solar is just panels and price. The reality is that racking, inverters, interconnection, permits, shipping, and labor can swing the total more than the module brand.

Checkpoint: one page with location, annual kWh, roof or ground mount, backup needs, EV load, and who owns the warranty.

Step 2: Pull the current module datasheet—not a blog post

For First Solar (often searched as first-solar), go to firstsolar.com and download the current Series 6 or Series 7 datasheet. Check dimensions, temperature coefficient, connector type, and the published annual degradation rate. First Solar's Series 6 datasheet has historically cited roughly 0.5%/year; verify the current number for the exact model.

I'm not going to tell you CdTe is universally better than c-Si or the other way around. If you ask me, anyone who says one technology wins in every condition is selling, not advising.

Checkpoint: datasheet version date and model number match the quote.

Step 3: Size the array with real annual kWh

If you're asking how many solar panel to power a house, don't use a rule of thumb. Use annual kWh, local sun hours, and panel wattage.

Example: a U.S. household using about 11,000 kWh/year (EIA residential average range, 2023) in a 4.5 sun-hour location. A 400W panel produces about 1.8 kWh/day by rough math, or 657 kWh/year. 11,000 / 657 = about 17 panels. Use NREL PVWatts for a better local estimate.

Checkpoint: your installer's panel count matches a written load calculation, not a sales brochure.

Step 4: Check EV charger load and permit before buying the box

For an EV charger installation in Indian Head Park, Illinois, don't order the charger first. Confirm panel capacity, circuit size, run length, permit requirements, and utility interconnection with the Village and ComEd.

In 2022, I ordered a Level 2 charger before the load calc. The $3,200 order sat in the box for six weeks while we upgraded the panel. That error cost $890 in redo plus a one-week delay.

Checkpoint: electrical load calculation, permit path, and installer license verified before payment.

Step 5: Compare portable power stations by usable specs

A solar portable power station is not a whole-home backup unless the load math says so. Check usable watt-hours, continuous output, surge output, MPPT input range, pass-through charging, battery chemistry, and cycle life.

People assume the biggest number on the box is the number that matters. What they don't see is usable capacity after depth-of-discharge limits and inverter losses.

Checkpoint: a load list with run hours and a recharge time estimate from solar input.

Step 6: Ask what's NOT included before you ask for the price

I've learned to ask 'what's NOT included' before 'what's the price.' The vendor who lists all fees upfront—even if the total looks higher—usually costs less in the end.

Watch for shipping, tax, permit fees, interconnection fees, racking, monitoring, removal and disposal, and EV circuit upgrades. In my opinion, a quote without line items isn't a quote; it's a starting point for change orders.

Checkpoint: every excluded item written on the quote, not promised verbally.

Step 7: Verify permits, interconnection, and local rules

Solar and EV paperwork is local. For Indian Head Park, verify current requirements with the Village and ComEd. For utility-scale projects, check the interconnection queue and land-use approvals.

After the third rejection in Q1 2024, I created our pre-check list. Most rejections weren't technical—they were missing signatures, wrong site plans, or outdated utility forms.

Checkpoint: permit packet reviewed by someone who has submitted one in the last 12 months.

Step 8: Pressure-test market claims with dated sources

Market claims need timestamps. If you're checking the first half 2024 solar installations India GW figure, Mercom India reported about 15 GW in August 2024—verify the current figure at mercomindia.com. If a salesperson cites First Solar's 66 GW backlog, ask for the quarter; backlog changes.

Prices and policies move. Use a source date, not 'in recent years.'

Checkpoint: every number in the quote or proposal has a source and a date.

Step 9: Run a pre-signature red-team review

Before signing, have someone who doesn't want the sale read the quote. We've caught 47 potential errors using this checklist in the past 18 months.

Even after choosing the higher all-in quote, I kept second-guessing. What if the cheaper vendor was fine? The three weeks until permit approval were stressful.

Checkpoint: red-team notes resolved in writing before deposit.

Common mistakes and notes

• Don't compare utility-scale First Solar $/W with residential $/W. Different scope, different risk.
• Don't accept verbal degradation or warranty claims. Get the datasheet and warranty document.
• Don't skip the 'what's not included' line. Hidden fees rarely stay hidden.
• Don't use a solar portable power station as whole-home backup without a load calculation.
• Don't let search typos like 'first planet solar system' send you to the wrong datasheet. First Solar is a CdTe module manufacturer; Mercury is the first planet in the solar system.

So glad I paid for the permit pre-check. Almost skipped it to save $250, which would have meant a re-inspection delay. There's something satisfying about a quote that lists every fee. After years of change-order surprises, finally a clean comparison.

Pricing and policy details are for general reference only. Prices as of January 2025; verify current rates, incentives, and local requirements with official sources.