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We are extremely proud of our proposal and the information we provide. Our goal was simple, ensure we create a proposal that is easy to understand yet detailed enough to create transparency and trust. Solar provides so much benefit from improving the environment in which we live while also creating financial stability and predictability by locking in a homeowner’s electricity rate for 25 years and beyond. It is important to understand how we got to the numbers in your proposal which is why we have written this article. All of our calculations, featured figures, and descriptions are below. We strive to be the most transparent Residential Solar Company in the industry and hope our actions inspire others in the industry to do the same. Please reach out to us if you have any questions or comments.
Total kWh of electricity imported from the grid.
Total kWh usage.
Total kWh solar generation in the first year of the system’s operation.
Aggregated kWh storage capacity of all batteries designed for that system.
The ratio between actual kWh generation divided by the maximum possible energy output for that system’s nameplate capacity in 1 year. Given by:
The capacity factor roughly ranges between 10 – 25% depending on location and system design.
The total kWh generation divided by the annual electricity usage.
The average daily solar generation in the first year of the system’s operation.
The total kWh generation divided by the annual electricity usage.
Percentage of a project’s annual usage that is covered entirely by solar generation. Given by:
Rated kW Capacity of the PV system.
Percentage of energy produced by the solar system that is self-consumed, or used directed by the load.
The system lifetime of the designed system.
Total energy cost in the first year after installing solar. This includes the utility bill cost plus any payment amounts from loans, leases, regular payments or PPAs
The savings in energy cost if the customer was to install the system designed in the first year. This is given by the old electricity bill minus the new electricity bill plus any payment amounts.
Estimated savings per electricity bill received in the first year of installing the system.
The estimated lifetime electricity bill savings.
The estimated electricity bill savings in the first year of installing the system.
The estimated electricity bill in the first year of installing the system.
The estimated electricity bill if the system was not installed.
The estimated total electricity bill paid if the system was installed over its lifetime.
The estimated total electricity bill paid if the system was not installed over its lifetime.
Simple payback period. It refers to the time it takes to recover the cost of an investment.
The time it takes to recover the cost of an investment, taking into account the time value of money as defined by the discount rate.
The discount rate can be set in Control > Design & Hardware > Setbacks & Design Settings > Simulation Settings.
The value of all future cash flows over the system lifetime.
The discount rate can be set in Control > Design & Hardware > Setbacks & Design Settings > Simulation Settings.
The ratio of profit or loss over the system lifetime with the initial investment of purchasing that system, expressed as a percentage. Also known as the rate of return (RoR).
Also known as the internal rate of return, is a discount rate that makes the net present value of all cash flows from a project equal to zero.
The levelized cost of energy (LCOE) is the average avoided cost per kWh of electricity produced by the system.
The discount rate can be set in Control > Design & Hardware > Setbacks & Design Settings > Simulation Settings.
Lifetime net savings. This value can be negative if cost is greater than savings.
The total system price is the price to the customer before applying any upfront incentives.
The purchase price is the principal price the customer has to pay for the system. It is given by:
It shows the payment amount for each period as defined by loans, leases and regular payments.
For cash payments, it is the same as the Purchase Price, or upfront amount the customer has to pay.
For PPAs, it shows the $/kWh cost of electricity as agreed upon on the PPA.
The net system price is the cost to the customer after accounting for all incentives. This includes any direct customer incentives received after installing the system.
It shows the payment amount for each period as defined by loans, leases and regular payments.
For cash payments, it is the same as the Net System Price, or the cost to the customer after accounting for all incentives.
For PPAs, it shows the $/kWh cost of electricity as agreed upon in the PPA.
It is the same as Net Payment Amount inc tax.
The only difference is that the featured figure text for cash payment options is “Net Cost of this solar system” instead of “Net System Price including tax”.
TSP Chicago
