Blog » Economics » Introducing the Certasun Production Guarantee

Introducing the Certasun Production Guarantee

by | March 30, 2019

So you’re thinking about going solar?  Great idea!  But, make sure you get an energy production guarantee.

A production guarantee is a vote of confidence for your system.  It’s the installer saying that you’ll get the benefits described and if for some reason you don’t, you’ll be made whole.

What exactly is an energy production guarantee?

An energy production guarantee is a guarantee of the actual energy output of a solar system.  Energy (not power) is what you currently buy from ComEd.  If you want to stop paying ComEd for energy, your solar system has to produce the energy you need.  But will it?

An energy production guarantee is a guarantee that either (1) your system produces what was estimated, or (2) if it doesn’t, you get reimbursed.

The Certasun Production Guarantee

If you buy a solar system from Certasun, our contract with you guarantees:

  1. The system will produce at least 90% of estimated production for the next 25 years.
  2. If it falls short, we’ll pay you back at 12.4¢ per kWh.

How this is different from a “power warranty”

An energy production guarantee should be explicitly contrasted with a power warranty.  A power warranty describes the solar system’s capacity to produce energy, but does not guarantee the energy actually produced.

Power is measured in watts (W) or kilowatts (kW).  A typical solar panel might be 300W.  What this means is that under laboratory test conditions, the instantaneous output of the system would be 300W.   But this says nothing about how much energy (measured in kilowatt-hours, or kWh) that 300W panel will produce when it’s on your actual roof.

For example, a 300W solar panel will produce zero energy if it’s installed in your basement (a silly idea but useful for the sake of illustration); on the other hand, the same panel might produce 400 kWh per year if it’s installed on your roof.  But in either location, it technically has the same capacity to produce energy (meaning it would be in compliance with a power warranty).

How much energy the panel produces when it’s on your roof is a function of:

  1. Its power (more powerful panels do produce more energy)
  2. The “sunniness” of its geographic location
  3. Shading from trees or other structures
  4. The pitch and azimuth (orientation) of the roof
  5. The quality of the installation

A production guarantee is effectively a guarantee that the design and installation were done right.

Why you want a production guarantee

If you’re going solar, your installer should give you a production guarantee.  If all you have is a power warranty, you’re relying on your installer to remove a faulty panel, ship it off to a lab, and then run tests on it.  Now, the SunPower power warranty covers those costs (most other power warranties do not).  But a power warranty is not the simplest warranty for which to file a claim.

On the other hand, energy production is easily measured by the monitoring device that comes with the system.  If your system is under-producing, we’ll know right away.  And in that unlikely event, all we have to do is cut you a check.

This post was written by Jesse Feinberg.
Jesse is one of Certasun's founders.

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