AriSEIA reported this past November that the TPT exemption covering the installation of solar energy systems would expire at the end of the year with new regulations going into effect on January 1, 2017. A bill was introduced in the last session of the Arizona Legislature to make the exception permanent, but it did not receive a hearing. Since there was no bill passed to extend the exemption, the new regulations are in effect.  Below is the notice TEP sent to its contractors (slightly updated by the Solar Center):

The First Regular Session of the 53rd Arizona Legislature has adjourned and we wanted to make readers of the Arizona Solar Center aware of an important change that may affect your tax liability as a solar contractor. As of January 1, 2017, the gross proceeds of sales or gross income derived from a contract to provide and install a solar energy device are now taxable under the State of Arizona's transaction privilege tax statute (see Arizona Revised Statutes Section 42-5075.B.13). An exemption for this activity had been enacted in 1996 with a sunset date of January 1, 2017. A legislator in UES service territory, Senator Sonny Borelli (R - Lake Havasu City), had introduced legislation that would have eliminated the sunset date and made the tax exemption permanent. However, the bill did not receive a hearing and this exemption is no longer effective as of January 1, 2017. Additionally, a policy rider effecting the exemption was not included in the budget signed by Governor Ducey.

From December 31, 1996 and up to January 1, 2017, the gross proceeds of sales or gross income derived from a contract to provide and install a solar energy device (commonly called Sales Tax in Arizona) were exempt.  It appears that this is no longer the situation and sales of solar devices may be subject to sales tax (TPT).  Thank your legislators.

Editorial Note:  A review of the Arizona Revised Statutes http://www.azleg.gov/arstitle/ Title 42-5061 (M) on 6-6-2017 indicates "M. There shall be deducted from the tax base the amount received from sales of solar energy devices.....".  Apparently only contracting is affected by the above TPT change.  Watch this space for updates as the Arizona solar industry researches this subject.