For all of you who’ve spent time in the last few weeks digging out driveways and walking through winter wonderlands, you probably have a newfound respect for the power of Mother Nature. At SunPower, we have the same respect, as we design and test our panels to maintain their high-efficiency production during the most extreme weather. In fact, a recent hailstorm at a customer installation in Phoenix, AZ demonstrated the importance of all-weather solar panel durability.

Back in October 2010, an afternoon hailstorm struck the Cowley Industrial Complex on the south side of Phoenix. The golf ball-sized hail was so large and ferocious that after the storm our local dealer, Don Herman of Empire Power Systems, said "It looked like someone had machine-gunned the complex with large bullets." However, the building’s southern end, which houses a 6.5 acre panel SunPower solar installation, was virtually spotless. More importantly, the solar panel’s continued to run at capacity producing 2.5 MW of electricity (enough to power 340 homes). In fact, out of the 8,000 panels that made up the installation, only three panels were damaged.

The tiles used in the Cowley installations were SunPower T5 tiles. Since the T5 panel is a non-penetrating model, it doesn’t require drilling holes in a building’s roof to hold the installation in place. This saved Cowley from melt water leaking through the ceiling of its distribution center and slowing operations. Facing the most extreme weather conditions, Cowley was able to maintain business as usual (and keep generating solar power)!

Next time you have to head out the door with shovel in hand, remember that your reliable SunPower panels should be in perfect operating condition. You’ll likely only need to brush the snow off of them to provide clear access to sunlight. Are your panels steadily pumping out power while surrounded by snow? If so, we’d love to see pictures of your installation braving the winter elements on our SunPower Facebook Wall.

Today, we have a story of solar for elephants, along with many other animals, at the Perth Zoo in Western Australia.



Earlier this month, the Perth Zoo unveiled the city’s largest solar site installation: a 91 kW SunPower system spanning the zoo’s elephant barn and seven additional structures. This 303-panel installation is the first of two stages in a $2.7 million renewable generation project at the zoo. With over 300 sunny days each year, this installation will provide the lion’s share of energy to several zoo buildings.



Perth Zoo went solar to demonstrate its commitment to sustainability and conservation. The installations around the zoo and accompanying educational materials will serve as an ideal teaching tool for the 630,000 visitors who pass through each year. Many young children and their families will learn about the environmental benefits of solar energy while checking out the elephant den.

The Perth Zoo’s solar investment was made possible through joint funding by the state and federal governments. It is part of the Perth Solar City program, a $73.5 million initiative aimed at making solar power a viable alternative for local communities and encouraging local residents and businesses to consider solar energy solutions.

Government solar installations like that at the Perth Zoo are incredibly valuable in influencing the uptake of solar energy. Not only do these installations make financial sense for local governments looking to diminish costs and protect themselves against energy volatility, they also show others that solar investments are possible. That’s a lesson the resident of Perth, and the elephants, won’t forget.

This week’s post is the second installment of our utility-scale solar blog series featuring Matt Campbell, Director of Utility Products and Market Development at SunPower.

In this installment, Campbell discusses the advantages of the Oasis Power Plant solution for utilities, solar power plant developers and investors. He describes how Oasis streamlines the utility-scale power plant construction and development process by providing pre-engineered modules for quicker installation.

According to Campbell, “The first [way that Oasis streamlines the construction process] is, by having a pre-engineered block. What that means is, when you have a new piece of land, it becomes a very simple matter to overlay the pre-engineered power blocks over the terrain… So again, a standard kit of designs that enable a very fast preliminary design development process.”

He goes on to discuss the benefits of pre-qualification by investors, and highlights how SunPower’s Oasis technology enhances energy production at its peak:

“The Oasis system has been designed from the bottom up to optimize production when the utility is used the most, which is at peak demand. Now if you look at a place like California, the peak demand for energy is the summer in the afternoon, when on a hot day, most people have their air conditioning systems running, which creates an enormous strain on the grid and on their power plants. So what Oasis does is by using an optimized tracking system design, it’s producing up to forty percent more power during that summer afternoon peak period, which in the southwest of the United States is the peak of demand.”

Stay tuned - in two weeks, Matt Campbell will discuss Levelized Cost of Energy, or LCOE, a way to compare the cost of generation over the life of the system for differing generation technologies.

Check out the video below to learn more about SunPower Oasis advantages, and please join the discussion on our Facebook community at www.facebook.com/sunpower or follow us on Twitter (@SunPower) for the latest solar PV technology updates.

For this week’s entry in the Solar Basics series, we’re revisiting the topic of efficiency. Everyone spanning installers, manufacturers, online commenters and industry experts will stress that efficiency is one of the most important drivers in the solar purchase process. But few resources provide a clear explanation of what efficiency is, how efficiency is calculated and what factors influence efficiency. Today we’ll try and clear up the confusion.

For starters, here’s an informative interview with SunPower Founder and President Emeritus Dick Swanson in which he explains solar panel efficiency and how it benefits homeowners:

Dr. Swanson touches on two key areas that influence the efficiency of solar power systems. First is the rate at which the solar panels convert the energy in sunlight into energy that will power your home. This is basic efficiency. To use a concept that most consumers are familiar with, it’s analogous to fuel efficiency in a vehicle, or that rate at which fuel converts into miles traveled. Just like with a car, a solar panel with high efficiency levels is more favorable (although sunlight is free while gas prices are volatile!).

Second are the barriers to efficiency that residents experience due to the physical location and setup of their homes. Key among these barriers is usable roof space. Certain roof areas might be unsuitable for solar panels due to their size, the direction they face and the ability of the roof to support panels. Sources of shade, especially trees, can also affect usable roof space.

When homeowners compute all these factors, they’re left with a specific tract of their roof that is suitable for solar. In many cases, homeowners want even fewer panels than possible due to cost or aesthetic reasons.  In making the solar purchase decision, it’s in the best interest of any owner to ensure that they can deliver the most energy per square foot of solar panels installed. For space-constrained owners, this ensures they can achieve maximum output. For owners worried about aesthetics, they can generate the same amount of power in a smaller amount of space. Taking into account reliability factors from our last Solar Basics post, highly-efficient and reliable solar power systems allow homeowners to generate the most electricity over the lifetime of their system.

At SunPower, we aim for transparency. On our website, you can find listings of our residential panel offerings and how their efficiency levels stack up against the competition.  Here’s a video detailing how SunPower’s solar power systems are the most efficient in the world:

If you have any additional questions about solar panel efficiency or the efficiency of SunPower products, please post them to our Facebook page or leave them below.

For today’s installment of Solar Basics, we’re going to discuss the importance of system reliability. SunPower solar technology delivers the highest reliability in the industry, so our dealers and salespeople talk a lot about reliability with prospective customers. But for customers who are comparing many different manufacturers at many different price points, they want to know how to measure reliability and why it matters. Those are very fair questions. Here’s one video from SunPower dealer Independent Power Systems of Boulder, CO, which demonstrates one type of reliability:

SUNPOWER HAILSTORM VIDEO:

Solar system reliability is best summed up by three metrics:

1.    The functional lifetime of the panels - All dealers should share the functional lifetime of the panels. This is the number of years the panels are expected to produce power (as set by the manufacturer).

2.     How well the panels perform over their lifetime - Just like a computer processor or a rechargeable battery, solar panel production degrades over time. Some panels maintain higher levels of production over the course of their lifetime.

3.     Energy production continuity - Since solar panels need to face the sun, they are subject to the elements. Over a 25-year lifetime, the panels are exposed to a lot of rainstorms, hailstorms, snowstorms and even the occasional hurricane. All of these factors represent risks that could knock a panel offline. All panels differ on how well they can handle extreme weather and maintain consistent uptime. Be sure to ask your dealer for more details.

Reliability is important when you take into consideration the total cost of ownership over the lifetime of your panels. You are not receiving the full value of your investment whenever your panels aren’t functioning properly. A standard 25-year warranty may not cover you for everything. In addition, imagine having to go through the hassles of dealing with the company to replace the panels and the loss of energy production - and, what if this happened every two years or less? The losses can add up quickly…

To make sure you are investing in a reliable solar energy system, we’d recommend you to get answers to the following questions before you buy:

1.      How much experience does the company have installing and manufacturing solar panels?
2.      How extensively do they test their panels?
3.      What certifications do they have? Do they settle for the industry standard or go beyond it?
4.      How much of the design and manufacturing process does the company control

At SunPower, we take reliability very seriously. Check out this video detailing how we build and test our solar panels to provide the highest level of reliability in the industry:

Today on the blog, we're unveiling a new series of ongoing posts called 'Solar Basics'. These posts are intended to answer frequent questions we receive about solar power, ranging from how solar works to some tips for finding the right solar solution for you. If you have any questions you’d like answered, please post them to our Facebook page or leave them in the blog comments for any Solar Basics posting.

At our recent dealer conference, one of our dealers said he gets a lot of customer questions about the terminology associated with the power and electricity output of SunPower solar systems. Specifically, customers are confused about when to use the term 'kilowatt' and when to use ‘kilowatt-hour’ (and what both terms even mean). So here’s a simple explanation you can use when talking with a potential dealer or explaining your system’s output.

Kilowatt (kW) is a measure of power. It’s important to understand that power is a rate statistic that measures the flow of energy conversion within a system (and not the energy itself). When describing a solar installation, kilowatts provide a measure of system capacity. For instance, a 10 kW system acting at full capacity will have 10 kW of energy flowing through at any singular moment.

Kilowatt-hour (kWh) is a measure of electricity. Unlike kilowatts, kilowatt-hour is not a rate statistic and is cumulative. In fact, kilowatt-hours represent the amount of power (in kilowatts) used over a period of time (hours).

One useful example is to think of a stomach, which is a kind of engine that we all have within our bodies. The stomach gets fuel in the form of food, which uses food energy (otherwise known as calories) to power the body. Imagine that you have a completely full stomach beginning the process of digestion. At full capacity, the stomach will digest food and power the body at a specific rate (say 120 calories per hour - a rate statistic similar to kilowatts). Over three hours, your somewhat-less-full stomach will have produced 360 calories of energy (a counting statistic similar to kilowatt-hour). That's enough to power an hour of moderate exercise, so there's a good excuse to burn those calories.

Now back to solar. Let’s say you have a guest over who wants to know how much energy you're producing with your SunPower rooftop installation. You have a 'perfect' 10 kW AC power system that includes all system and module level losses, meaning that at peak production the system is producing exactly 10 kW of power. From 10 am to 4 pm, your system is running at full capacity (a perfect solar day!) with peak sun hours of 5.8 hours. And thanks to SunPower’s market-leading panel efficiency, less roof space is required to capture the 10 kW system output and feed it into your home. To compute the energy output of those six hours, follow this simple calculation:

10 kW AC x 5.8 peak sun hours = 50 kWh from 10am to 4pm

That’s a lot of energy! We hope this helps clear up any confusion around kilowatts and kilowatt-hours. And if you’re a SunPower customer, be sure to check out our in-home monitoring tool to get up-to-date readings of how many kilowatt-hours your system is producing each day.

If you have any further questions or comments, please post them to our Facebook page or leave them below.

Today on the blog, we're unveiling a new series of ongoing posts called 'Solar Basics'. These posts are intended to answer frequent questions we receive about solar power, ranging from how solar works to some tips for finding the right solar solution for you. If you have any questions you’d like answered, please post them to our Facebook page or leave them in the blog comments for any Solar Basics posting.

Kilowatt (kW) is a measure of power. It’s important to understand that power is a rate statistic that measures the flow of energy conversion within a system (and not the energy itself). When describing a solar installation, kilowatts provide a measure of system capacity. For instance, a 10 kW system acting at full capacity will have 10 kW of energy flowing through at any singular moment.

Kilowatt-hour (kWh) is a measure of electricity. Unlike kilowatts, kilowatt-hour is not a rate statistic and is cumulative. In fact, kilowatt-hours represent the amount of power (in kilowatts) used over a period of time (hours).

Now back to solar. Let’s say you have a guest over who wants to know how much energy you're producing with your SunPower rooftop installation. You have a 'perfect' 10 kW AC power system that includes all system and module level losses, meaning that at peak production the system is producing exactly 10 kW of power. From 10 am to 4 pm, your system is running at full capacity (a perfect solar day!) with peak sun hours of 5.8 hours. And thanks to SunPower’s market-leading panel efficiency, less roof space is required to capture the 10 kW system output and feed it into your home. To compute the energy output of those six hours, follow this simple calculation:

10 kW AC x 5.8 peak sun hours = 50 kWh from 10am to 4pm

That’s a lot of energy! We hope this helps clear up any confusion around kilowatts and kilowatt-hours. And if you’re a SunPower customer, be sure to check out our in-home monitoring tool to get up-to-date readings of how many kilowatt-hours your system is producing each day.

If you have any further questions or comments, please post them to our Facebook page or leave them below.