Ask a Solar Engineer - Backup Systems (Part 3)

This is the third in a series of posts on back-up for solar power systems. Read on, and learn more about how you can turn your public utility into your solar back-up with a grid-tied system.

Grid-Tied Systems

Where utility power is available, a grid-tied solar power system can supply most of the energy needed, using the power from the utility as a back-up, in place of batteries. Because these grid-connected systems are much less expensive to purchase and operate than battery back-up systems--and because the owners can effectively sell power back to the utilities--these systems are the most popular.

Public Utilities as Back-up

One benefit of the grid-tied system is that owners can both buy and sell electricity each month. This is because electricity generated by the solar energy system can be used on-site, or fed through a meter into the utility grid. California's net metering law, for example, provides that all utilities must allow customers with solar electric systems rated up to 1.5 MW to interconnect with the local utility grid, and receive retail value for the electricity produced. With a grid-tied system, the utility serves as a back-up to the solar power system, similar to the way in which batteries do in stand-alone (off-grid) systems.

Time of Use Billing

The other benefit of a grid-tied power system is the Time of Use billing structure, which is measured with special meters that calculate how much and when electricity is used. These rate structures make grid-tied systems even more economical.

For example, PG&E's Time Of Use rate would allow you to run your electric meter backwards at up to $0.44 per kWh during summer weekday afternoons (when your solar energy system generates its maximum amount of power), and purchase electricity at all other times at $0.12 per kWh! This Time of Use billing method effectively improves the economics of your solar power electric system by 15 to 40%.

Hopefully this three-part overview of backup systems will be helpful when you decided how you want to back up your solar power system.

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Solar Advocacy

They say that sometimes, it’s all about whom you know. But when you’re hoping to affect positive change within a long-established sector like the electric power industry, it might be more accurate to say that it’s really about advocacy.

Having an effective advocate by your side can make an incredible difference in opening minds, sharing information, and growing support for a burgeoning industry. In that vein, we in the Westinghouse Solar family were thrilled when we announced recently that internationally recognized environmental activist Robert F. Kennedy, Jr. will be joining our Board of Advisors.

Extending his family’s longstanding legacy of support of the arts, human rights, and health care, Mr. Kennedy has devoted much of his career to environmental stewardship. His work with Riverkeeper, a clean water advocacy group in New York, and the Waterkeeper Alliance, dedicated to protecting water from polluters, has established him as a tireless supporter of environmental preservation efforts. In recent months he has also spoken out strongly on the Gulf oil spill, coal mining, and alternative energy sources.

So to our new friend and colleague we say, Welcome. We look forward to working together to bring solar to rooftops across America, and to help create new jobs through our industry’s continued growth.

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Ask a Solar Engineer – Backup Systems (Part 2)

Today, we continue our review of the options for solar backup systems. We’re going to be reviewing the ways the generator backup works.

Cost-Effective Backup: Generators

For a given level of power output, generators are usually the least expensive option for backup power production. In the vast majority of residences Akeena evaluates, generators end up being the best choice to provide the most reliable and cost-effective source of extended backup power, especially in areas where frequent electricity power outages are the norm. They are independent motors powered by gasoline or are electrical and fed by the utility and connect directly into the electrical system of your home. Homeowners in areas with infrequent power outages (the majority) do not typically need power backup of any kind for a grid-tied solar power system to be highly effective.

Saving (Power) for a Rainy Day

In these cases where backup power is a must, we recommend installing a relatively inexpensive generator in conjunction with a manual transfer switch tied directly to the electrical panel on your house. If it is a utility powered generator, the transfer switch directs the source of power for critical loads from the utility to the generator--without back-feeding the electric grid. For a gasoline powered generator, it is manually turned on and off and powered by gasoline poured directly into the unit by the homeowner.

During a period of power outage, the transfer switch is engaged and the generator is started. This provides power to the critical loads in the house.

In the next post, we’ll discuss the benefits of grid-tied systems. Stay up-to-date by following us on Twitter!

Ask a Solar Eningeer - Backup Systems (Part 1)

When we are out at events or meeting with customers, we get a lot of questions — the move to solar is no small affair, after all. One of the things a lot of people have questions about is the type of back-up they might need for their solar power system. I recently interviewed one of our lead installation engineers and asked him about several of the most common questions about solar backup, and what follows is the insight he shared with me.

Types of Backup

There are 3 types of backups that can be used on cloudy days and at night, when a solar system does not produce enough electricity to meet user needs. One is battery storage, where a battery provides users with supplemental electricity. Another is generator backup, where users get extra electricity from a generator. And the third is a purely grid-tied power system, where users get the added electricity from their utility provider. In this post, we’ll focus on the battery storage system.

Battery Storage: Supporting Uninterrupted Service

Solar energy systems with battery storage are being used by businesses and residences all over the world to power a wide range of building equipment, lighting, appliances, computers, or communications equipment. In general, these systems are best for situations where backup power must be instantly available without interruption (for example, to power computers). They are also good for remote applications in which utility power is not available and a generator is not desirable.

Batteries are an additional expense however, require maintenance, only last 5-10 years, decrease system efficiency, and result in a more complicated system. If you have access to grid power, you can take advantage of Net Metering (where available) to simply sell your excess power back to the utility during the day and draw utility power at night - at 100% efficiency. Most solar customers opt for a grid-tied system and purchase a standby generator with a properly installed manual transfer switch, avoiding the additional expenses related to batteries, and having backup power available for as long as they have fuel.

Check back next time, when we’ll continue this discussion with an overview of generator-based solar backup systems.

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Solar and Home Resale Value

Thinking of selling your house? As you know, the economic downturn of the last few years has been a game-changer for the real estate market. Buyers today are in the prime position of being able to hold out and get the best bang for their buck, so you need to be prepared.

If you’ve been thinking about going solar and have been doing your research, you probably already know that a home powered by solar energy can command significantly higher prices than the average, utility-powered home next door. But how does brand play into this equation?

As with any major purchase, reputation, quality, and reliability are key. When purchasing a solar-powered home, a deciding factor for every potential buyer is the brand of solar installation on the home. Having to repair or replace a defective or underperforming solar power system will be a major barrier to purchase, so they want only the best.

Make sure your solar system is backed by an established company with a well-known and respected brand, and you will see a nice return on your investment when it’s time to sell.

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Solar Power Systems: Does Size Matter (Part 2)

In the previous post, we talked about the criteria to consider when deciding on the size of solar power system you will need. Today, we’re going to dig into the different levels of offset you can garner for your energy bills with solar power.

So let’s kick this off with a question: How much coverage do you want?

90-100% Bill Offset
If, based upon the criteria outlined in the previous post, your family plans to use more electricity over the next ten years, or if your goal is to eliminate your home’s energy usage from your carbon footprint entirely, this is the amount of offset you will need. One bonus of this is that if your solar production levels end up exceeding the needs of your home, you can also use this to offset other personal energy use that is not tied to your home in order to work toward a low-to-zero personal carbon footprint!

80% Bill Offset
This is the sweet spot. It is generally acknowledged that the ideal bill coverage is 80%, as it serves to drop the electrical usage of most average homes into the lowest (and least expensive) tier of billing rates. With the “Time of Use” billing structure, which is measured with special meters that calculate how much and when electricity is used, 80% of bill coverage is the level at which the solar power system pays for itself the fastest for most homeowners.

70% Bill Offset
This is a very cost-effective way to go if you are planning to use less electricity, conduct a Home Energy Audit or are short on roof space for the number of solar panels needed to fully offset your electricity usage. This option allows you to go solar now to take advantage of government rebate programs so you can lock-in low energy costs. Even if your energy usage drops up to 30% over time, this size system makes economic sense since you will already enjoy low monthly energy bills immediately with a faster ROI thanks to your new solar power system!

Whether your offset goals are moderate or aggressive, there is a solar power system that is right for you. If you have questions, schedule a free solar power evaluation, and we’ll help you decide which size system you need.

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An Exciting New Partnership

Recently, you may have heard some exciting news about Akeena Solar. Akeena Solar and Westinghouse just announced that they will be partnering to make Akeena’s Andalay solar power system available to more customers across North America than ever before.

Beginning this summer, Akeena’s Andalay brand will become Westinghouse Solar. The Westinghouse reputation for delivering safe, reliable, and efficient energy products and solutions is unparalleled. With this new partnership, our award-winning Andalay technology will continue to give customers superior performance and service. And of course, all warrantees will be honored by Westinghouse Solar.

We’re really excited about this here at Akeena, and we hope you are, too. For more information, visit the new online home of Westinghouse Solar.