Commercial solar proposal software needs to do more than calculate how much electricity a set of panels could produce. Installers also need it to show clients what the proposed system will cost, how much it could save and how long the investment could take to pay back.
This guide explains what you should include in the proposal, the information you need to collect from the client to calculate the savings and payback, and how to present those figures in a quote or sales meeting.
What should commercial solar proposal software do?
Commercial solar proposal software should cover three jobs:
| Job | What you use the software for |
|---|---|
| Plan the system | Lay out the panels, choose the proposed equipment and estimate how much electricity the system could produce. |
| Calculate the savings and payback | Compare the project cost with the expected savings and income. Show how long these could take to cover the cost of the installation. |
| Prepare the proposal | Put the system design, price, calculations and assumptions into a document the client can review and approve. |
Some solar design and proposal software packages let you do all three jobs in one place, for simplicity and speed.
Others handle only one or two, so you may design the system in one tool, calculate the savings in another and build the proposal in a third. Using three tools may take longer, but it lets you choose the best one for each job.
If you do split the work this way, make sure you carry the same panel count, equipment, generation estimate, project cost and assumptions through each tool. Otherwise, you could design a 500-panel system but show the client savings and payback based on only 450 panels.
What information do you need from the client?
Ask the client for information about the site, its electricity use, the prices it pays, its grid connection and any planned changes. You need this before you can produce more than a rough estimate.
| Information | What to ask for | Why you need it |
|---|---|---|
| The site and roof | The site address, opening hours, roof plans and any previous surveys | To see where the panels could go and estimate how much electricity they could produce |
| Electricity use | Recent bills and 12 complete months of half-hourly data for every meter | To see how much electricity the site buys from the grid and when |
| Electricity prices | The current electricity contract, unit rates and any extra charges | To calculate how much the client could save by buying less electricity from the grid |
| Export payments | The rate paid for electricity sent to the grid | To calculate what the client could earn from solar electricity the site doesn’t use |
| Grid limits | Any limits on how much electricity the site can send to the grid, plus letters from the local network operator | To check how much solar electricity the site will be allowed to send to the grid |
| Existing equipment | Details of any solar panels, batteries or generators already at the site | To calculate how the proposed panels would work alongside the equipment already there |
| Future plans | Planned EV chargers, heat pumps, machinery, extensions or changes to opening hours | To include any planned changes to how much electricity the site will use and when |
| Budget and payback | How much the client can spend and how quickly it expects the project to pay for itself | To propose a system that meets the client’s budget and expected payback time |
If the client has several meters, ask for 12 months of half-hourly data for each one.
If the site already has solar panels, ask for the solar generation data as well. The site meter shows how much electricity the site buys from or sends to the grid. It doesn’t show the solar electricity used at the site.
What should you include in a commercial solar proposal to a client?
Your commercial solar proposal needs to show the client its constituent parts, what it will cost, how much the business could save or earn each year and how long it could take to recover the cost.
Here’s a breakdown:
| What to put in | What the client needs to see to make a decision |
|---|---|
| Proposed system | The panel layout, panel count, inverters and other equipment included in the quote |
| Expected generation | How much electricity the panels could produce each year and the assumptions used to calculate it |
| Project cost | The total price and what is included or excluded |
| Electricity savings | How much solar electricity the site is expected to use and how much less electricity it may need to buy from the grid |
| Export income | How much electricity may be sent to the grid and the rate used to calculate the income |
| Payback and return | The expected annual savings and income, how long they could take to cover the project cost and the return on investment |
| Assumptions and limits | The electricity prices, export rate, grid limits and other figures used in the calculations |
Make your proposal look like it was specifically prepared for that client. Use the client’s name and site images alongside their and your company logo, colours and contact details. Keep each page easy to scan, with minimal text, short tables, and, where it helps you illustrate a point, a simple graph or chart.
Structure the document in this way:
- What you’re proposing
- What it will cost
- How much the business could save or earn each year
- How long it could take to recover the cost
Then show how you worked out the figures. Keep the savings they make from solar electricity used at the site separate from any export income, and list the electricity prices, export rate and other assumptions you use in the calculations.
If possible, prepare a spreadsheet or live model with inputs the client can change. They can then see how different electricity prices, levels of site use, export rates and project costs affect the expected savings and payback.
How do you choose the best commercial solar proposal software?
Use one of your completed projects to run a full test on each software package you’re considering using. You already know what you installed, what it cost and the savings and payback you showed the client, so you can check whether each package produces the same results.
Check whether your team can:
- Import 12 months of half-hourly data for each meter
- Enter the client’s actual electricity prices, export rate and extra charges
- Check that the finished proposal uses the same panel count, panel and inverter models, generation estimate and quoted price as the system you designed
- Carry the same figures from the design into the calculations and proposal
- Show bill savings and export income separately
- Change the electricity price, export rate, site electricity use or installation price and see the revised savings and payback without starting the proposal again
- Add your branding and the client’s site details
- Save the figures and assumptions used in each version
Time how long each package takes and count how many figures your team has to enter more than once. You should also be able to see the prices, figures and formulas used to calculate the savings and payback.
If your solar design software already works well, keep it and add only the calculation or proposal software you’re missing. An all-in-one package can make more sense if your team spends too much time copying the same project details between different tools, but only if it does each job as well as the separate tools you use now.
If you also quote commercial battery storage, test the battery calculations separately. Solar generation figures alone can’t show how much a battery could save.
How much more could your client save by adding a battery?
How much more your client could save depends on how much spare solar electricity the site produces, what the client would be paid for sending it to the grid and what grid electricity costs when the site needs power later.
You also need to check how much electricity the battery can store and how quickly the inverter can charge or discharge it. Some electricity is lost on the way into and out of the battery, so you need to factor this in, too.
Comparing solar on its own with solar and a battery
For a solar and battery proposal, run the figures twice to calculate the difference. Here’s how:
- Model the proposed solar system without a battery
- Add the proposed battery without changing the solar design or the client’s information
The difference shows how much more the client could save or earn with the battery.
For the second calculation, add:
- The battery’s usable storage capacity
- How quickly it can charge and discharge
- How much electricity is lost during charging and discharging
- How much stored electricity the client wants to keep for the site
- Any limits set by the warranty
- The charging and discharging times the controls will use
Don’t treat every unit of stored solar electricity as a saving at the full grid price. If the client could have sold that electricity to the grid, subtract the export income they would have to give up.
For example, let’s say a site has 40 kWh of spare solar electricity, so exporting it at 8p per kWh would earn £3.20. The battery stores that electricity and supplies 36 kWh after losses to the site when grid electricity costs 24p per kWh. This cuts the client’s bill by £8.64.
The client is £5.44 better off from that use of the battery:
£8.64 bill saving − £3.20 export income given up = £5.44
Run the calculation across a full year. A commercial solar calculator should use the site’s half-hourly data to show when it is likely to have spare solar electricity and when it will need electricity from the battery.
Add the other savings, income and costs
The battery may also cut the bill through energy arbitrage. This means charging it from the grid when electricity is cheaper and supplying the site when electricity costs more. The battery may also cut costs through peak shaving, where it supplies part of the site’s electricity during its busiest periods. This may also delay the need to pay for a larger grid connection.
Some suitable battery setups in Great Britain can also earn income through battery energy trading. In your proposal, show this separately because the amount your client receives depends on market prices, the site’s contracts and how much stored electricity is available.
Remember not to count the same stored electricity twice. If the battery supplies the site at 6pm to cut the electricity bill, it can’t also export that electricity for a trade at 6pm.
Compare the extra annual savings and income with the extra cost of the battery, controls and installation. Don’t use the combined solar and battery savings to calculate the battery’s payback.
Base the proposal on the controls you plan to install. If the software will update the charging and discharging times using electricity prices, site demand and solar output, don’t calculate the savings using fixed times that repeat every day.
GridVolt’s solar and battery proposal software
GridVolt’s free simulator compares a proposed solar installation with the same project plus a battery. It models the bill savings Energy Manager could make and, for suitable sites in Great Britain, possible trading income from GridTrade.
Enter the client’s site data, tariff, export rate and project costs to show the difference in annual savings and payback. You can change these figures during the sales meeting and add the results to the proposal you prepare using your usual software.
After installation, Energy Manager uses live site data and the client’s actual tariff to update the battery’s charging and discharging times every 15 minutes. GridTrade can use compatible battery capacity left after the client’s site needs have been protected to earn trading income.
At one agricultural site, Energy Manager increased the savings made by the battery by 41% during its first 70 days. This wasn’t a 41% cut in the site’s whole electricity bill.
Fill in the form on the right or contact GridVolt to request simulator access and discuss Energy Manager or GridTrade.
Frequently asked questions
Can you prepare a commercial solar proposal without half-hourly data?
Yes, but only as an early budget estimate. An annual usage total tells you how much electricity the site uses, but not when it uses it. Without that timing, you can't reliably work out how much solar electricity the site will use, how much it will export or when a battery could reduce costs.
State your assumptions clearly in the first estimate. Before you confirm the battery size, annual savings and payback, check 12 complete months of half-hourly meter data against the client's recent bills.
Does proposal software replace site surveys and grid checks?
No. Proposal software can estimate generation, savings and payback from the information you enter. It can't carry out the site and technical checks that tell you whether the proposed system can be installed.
A structural specialist checks the roof, while an electrical designer checks the proposed installation. The local network operator confirms how much power the site can take from or send to the grid. Add these findings to the model before you give the client final figures.
How do you choose the best solar proposal software for commercial projects?
Start with what your current software already does well. If it already covers the design and solar generation estimate, you may only need another tool for tariff calculations, batteries or the finished proposal.
If you quote solar and batteries together, check that the software can use half-hourly data and the charging and discharging times planned for the battery. It should keep bill savings, export income and possible trading income separate and show what happens to savings and payback when you change the electricity price, export rate, site use or installation cost. If you use more than one tool, check that each one uses the same system design and assumptions.
What makes a commercial solar proposal different from one for a home?
A commercial proposal usually covers a larger site, more detailed electricity data and a more complicated approval process. You may be working with several roofs and meters, while the facilities team, finance team and board each check different parts of the project.
| Proposal for a home | Commercial proposal | |
|---|---|---|
| Where the panels will go | Usually one main roof | May include several roofs, a large flat roof, a car park or land next to the building |
| Electricity readings | Often one meter and a yearly usage figure | May include several meters and half-hourly data for each one |
| Electricity prices | Usually one or two unit rates | May include several rates and extra charges when the site takes a lot of power at once |
| Electricity sent to the grid | Usually covers a smaller amount | The local network may limit how much electricity the site can send back |
| Information you need from the client | Often uses a recent bill and the yearly usage figure for one meter | Ask for recent bills and half-hourly data for each meter |
| Who checks the proposal | The homeowner | Facilities staff may check the design, finance staff may check the savings and the board or a lender may approve the spending |
| What happens after approval | The installer prepares the final design and arranges the installation | Designers and engineers may prepare more detailed drawings, check the electrical work and update the approved design if anything changes |