Evaluating solar quotes can be a daunting process filled with graphs, figures, return on investment calculations, miscellaneous photos, and marketing material. Here we'll break down and explain each section commonly found in solar proposals and why they're included.
Here you'll find your information along with very basic information such as the size of the system in DC. Quickly check the address and see if your solar salesperson has a name. If you run into any problems you need to know who to talk to.
Here you'll find a satellite image of your property and a layout of the panels superimposed on a roof. Depending on the quality of the image and the skill level of your contractor there may be mistakes or things that don't make sense here. If you have any skylights, vents, or obstructions, or if that area of the roof gets a lot of shade these are all things to mention to your contractor.
Also listed here is other important information:
DC System Size: This is the wattage of each panel added up. To get this, take the wattage of each panel and multiply it by the number of panels. For example, 24 Bauer 500W panels make 12.0 kW DC.
AC System Size: This is the wattage of each inverter(s) added up. Your quote may have one inverter per panel, or it may have one inverter for all the panels, or somewhere in between. The AC system size will always be lower than the DC system size typically by 20-35%.
For a more detailed explanation of DC:AC ratio, click here,
First Year Production: This is what the system is expected to produce in its first year. A well-designed system should produce roughly the same each year for 25 years. This measurement is always in kWhs.
Consumption Offset: This number represents the percentage of your power bill you can offset with solar power. It is a common misconception that a higher offset number is automatically a better quote. If the DC and AC size of the system is the same, and the layout is the same, then the two systems will produce the same amount regardless of the brand or type of equipment used. It is highly recommended that you check the first year production and consumption offset percentage against your existing power bill.
Check Your Power Bill On the bottom right-hand side of your NSP power bill is your past 7 bi-monthly bills. If you add up the last 6 of them in the energy used column, you'll get your annual kWh consumption. In this case, you get 18,122 kWhs per year. You can then check the "first year production" against your historical annual consumption and make sure the consumption offset is accurate. In this example, 12,881 kWhs divided by 18,122 kWhs gives 71% offset. Unless all of your solar contractors are using the same annual kWh usage, you can't compare the consumption offset. Even if you told two contractors that your bill is "about $200 per month," one may add the grid connection fee (currently $19.17 per month), and one might subtract it. Estimated Annual Efficiency This one isn't commonly seen on solar proposals, but it's useful to measure if a company is being accurate with their estimates. The measurement is kWhs per kW DC per year. You can work out this number even if it isn't explicitly stated by dividing the First Year Production by the System Size in DC.
A particularly inefficient system (a due east facing roof, for example) would be around 900 kWhs per kW DC.
An extremely efficient system (due south at 45 degrees) would be around 1,250 kWhs per kW DC.
The average in Halifax is 1,150 kWhs per kW DC.
article-5.jpg144 KB Graphs and Figures Here we get to all the graphs and figures. This is also where you'll see the widest range of numbers in your proposals, and to be honest, they're mostly meaningless. Grid Tied Solar as an Investment Assumes:
Your electrical consumption won't decrease.
Your utility will raise the rate on power over the next 25-35 years.
The system will be in perfect working order for the next 25-35 years.
Excess summer production can be used in the winter at a 1-1 rate - i.e., the utility pays you the same amount for your power as you pay them for their power.
The graphs and figures attempt to explain that summer production can be banked for winter and that over time the value of the kWhs you produce will increase as the utility increases the rates. The faster they raise the rates, the faster your system pays for itself and the more money you save over its lifespan.
Explaining Each Assumption:
Under the Self-Generation Offset Program (LINK), which is provincial law, if you produce more power than you use annually, the excess is not credited. Therefore it's quite important that your electrical consumption won't decrease drastically, or you'll be giving power away for free.
Historically, the rate has increased 3.5% per year for the last 10 years. However, the rate increase for the past 2 years has been 7%. We have no idea if this trend will continue, but the higher you put the "escalation rate" the better the proposals will look.
This is by far the biggest assumption and probably the only thing that can "go wrong" with a solar investment. The choice of equipment regarding panels, inverters, racking, and the company that installs it is what makes this assumption accurate or not. Check out our "Solar Tricks and Traps" guide where we break down the various marketing and sales tactics that are harmful to the customer.
Again, under the Self-Generation Offset Program, this assumption is protected by law (check out bill 145 for more information). If the law were to change in a negative way, it would likely grandfather in existing systems, but with Nova Scotia's culture for green energy and the heavy investment at all levels (municipal, residential, commercial, non-profits), as well as investment by the provincial and federal government, we don't anticipate this changing any time soon.
Payback Period This section can sometimes be confusing. A typical solar system takes somewhere between 9 and 12 years to produce enough power to pay for itself. This inflection point is called the "payback period," but it's different from a loan term length. This number can vary quite a bit. Things like battery storage, ground mount racking, or loan interest can increase the payback period. Rebates and incentives will decrease it. Wattsup Solar does not offer in-house financing as we think it's a conflict of interest, especially as the current Greener Homes Loan program offers 0% interest with a 10-year term. If you're financing through the CGHL program, you're swapping a power bill for a loan payment that will be slightly higher ($40-50/month) than what you were paying before. The only way to swap a power bill for a loan payment that is the same or less is by having a term length of 15 years or more. It is nearly impossible to get an unsecured loan with a term length greater than 10 years.
article-4.jpg124 KB Equipment Details This section should always be on a solar proposal. It should clearly state both the brand and model number of the equipment (both panels and inverters) you're being proposed. If a proposal leaves out this information, or makes it ambiguous as to which equipment you're buying, it's probably for a good reason—i.e., they don't want you to know.
