Project Details:Top

Utility Name:	Tuscon Electric Power
Utility Type:	IOU
Funding Source(s):	System Benefit Charge
State:	Arizona | AZ
Region:	West
Utility Program(s):	Centralized Solar System: Photovoltaic,Solar Energy Credits (RECs, etc)
Technology:	PV

Project Description:Top

The Springerville Generating Station Photovoltaic System (Springerville) is a 4.6 MW utility-owned PV system located adjacent to a large coal-fired power plant and contributes power to a 10 MW water pump load for the plant. The initial design was done in 1997 and plant construction occurred in 2001 when Arizona implemented its Environmental Portfolio Standard (EPS) regulation and Tucson Electric Power (TEP) needed more PV electricity than could be delivered by customer-sited PV systems. The PV system was paid for by a solar rate rider as part of the EPS charge on customer bills, providing approximately $5 million/yr. A new Renewable Energy Standard Tariff (REST) replaced the EPS in 2008 and no longer has a solar specific set-aside. TEP owns all the Renewable Energy Credits (REC`s) from the project.

Springerville was built on land already owned by the utility and used the existing electric infrastructure of the coal-fired plant for the solar farm, reducing the amount of investment required. The levelized cost of PV electricity is reported as being estimated at between $0.092-0.096/kWh, which is extremely low, compared to TEP`s production cost of between $0.028 and $0.05/kWh. Due to scale the Balance of System (BOS) costs came to around $1.00/watt-dc, compared to a traditional cost of $2-5/watt-dc. PV modules comprised 80% of the cost of the system. Additionally, the PV System has a Data Acquisition System (DAS) that takes 10-second readings at extremely high resolution.

There were a lot of start-up problems with the initial inverters and some of the PV modules not functioning properly. These problems were solved in the first year and there have been no significant maintenance issues since then.

The motivations to build the plant were to achieve installation and operational experience with the (at the time) largest PV system in the world. Several cost cutting measures were taken, which brought the installed costs down significantly, even by today's standards. The utility also wanted to gain an understanding of utility-scale PV by comparing different PV modules/technologies in side-by-side arrays and to determine the ability of multiple inverters interconnected on the same power line to all safely disconnect if grid power is lost. Several studies have been published about the plant's operation, including the performance and grid impact of fast-moving cloud cover during the monsoon season.

Project Links:Top

General Project Description: http://greenwatts.com/Docs/TEPSolar.pdf 

Technical Details: http://greenwatts.com/pages/SolarStats/SolarTech.html

TEP Environmental Portfolio Standard ('07): http://greenwatts.com/Docs/ACCMidYear07.pdf

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