The US Postal Service Generates Clean Energy with 4 SunPower® Systems

This project demonstrates that solar electric power generated on-site is an affordable, clean and reliable energy source that reduces our dependency on foreign oil.”

– Ray Levinson, Environmental Compliance Manager, United States Postal Service

Background

Since 1776, the United States Postal Service has been the gateway to the household—binding friends, families and neighbors together. It is an independent federal agency that handles 42% of the world’s mail volume, with annual revenues of $65 billion.

Challenge

The Postal Service needed a cost-effective solution to operate more energy-efficient facilities and reduce their use of expensive peak electrical power. The United States Postal Service was also heeding the call to support the President’s Executive Order 13123 for Federal facilities to reduce energy consumption by 30%.

Solution

The United States Postal Service chose to implement an innovative combination of onsite renewable generation and demand control measures to reduce electrical demand and energy use at three of their locations. The first, the Marina Mail Processing Center, allowed for SunPower’s partnership with Virion Energy Service to install a 127 kW solar electric system atop the facility in Marina del Rey, the hub for energy information systems for 27 USPS sites. The United States Postal Service completed three additional sites with SunPower in Oakland, San Francisco and Sacramento to total a system capacity of over 1.4 MW.

Photovoltaic System Description

In addition to replacing grid power, the SunPower solar rooftop systems provide R-20 value thermal insulation to decrease building energy consumption, reducing heating and air-conditioning costs.

The SunPower® T0 Tracker System deployed in San Francisco features an innovative single-axis design enabling solar panels to automatically follow the path of the sun throughout the day to maximize the system’s energy generation. The result is higher electricity output that can increase energy capture by up to 20% more than fixed tilt arrays, as the tracker follows the sun from early morning to late afternoon.

Environmental Savings

By avoiding the purchase of fossil-fuel generated electricity, the US Postal Service solar installations spare the environment from thousands of tons of harmful emissions such as nitrous oxides, sulfur dioxide and carbon monoxide which are major contributors to smog, acid rain and global warming. Over the 25-year lifetime of the Marina Del Rey installation, the solar generated electricity will reduce emissions of carbon dioxide by over 4,000 tons. These emission reductions are equivalent to planting 216,000 trees, removing nearly 1,000 cars or not driving 14 million miles on the roadways of Los Angeles.

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Project Overview
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Marina Mail Processing Center     
Location:    Los Angeles, CA
Completed:    November 2001
System Size:    127 kW
Solar Electric Tiles:    845
Products:    SunPower® PowerGuard®

West Sacramento Distribution Center     
Location:    Sacramento, CA
Completed:    September 2004
System Size:    403 kW
Solar Electric Tiles:    2120
Products:    SunPower Parking System

San Francisco Distribution Center     
Location:    San Francisco, CA
Completed:    February 2006
System Size:    205 kW
Solar Electric Tiles:    1080
Products:    SunPower T0 Tracker

Oakland Distribution Center     
Location:    Oakland, CA
Completed:    July 2006
System Size:    911 kW
Solar Electric Tiles:    4380
Products:    SunPower® PowerGuard®

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Benefits
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Covering over 15,000 square feet of the facility’s roof, the installation on theMarina Mail Processing Center is capable of generating enough electricity during the day to power more than 120 homes. By installing solar photovoltaics on its existing buildings and new construction, the Postal Service has adopted a sound,sensible way to use distributed energy resources to meet renewable energy goals while minimizing the impact on the environment. Additionally, the United States Postal Service makes use of its untapped assets—its rooftops and parkingstructures—to generate clean, reliable energy.

The synergy of solar generation, coupled with a solar electric monitoring systemand demand control interface, ensures that the Postal Service will always achieve maximum peak demand savings from their solar electric system. The solar load controller enables the Postal Service to obtain 80% more demand charge savings ontheir utility bill from the solar installation.