The Solar Equipment Debate: Central Inverter vs. Micro-Inverter

Discussions about solar energy systems tend to focus on the solar modules themselves – the most visible component in the system — and often, neglect the other important piece of hardware: the inverter.

how solar power works

An inverter converts the DC electricity produced by the solar panels into AC electricity, which is what the home can actually use.

Some would argue that the choice of inverter is actually a more important decision than the solar module because the solar module plays a somewhat “passive” role in gathering the sunlight while the inverter is more actively managing it, while keeping track of (“data logging”) how much power is being produced.

There are two types of inverters: the “tried and true” central inverter (also called the string inverter) and the newer technology called the micro-inverter.  There is an ongoing debate as to which one is better.

Central inverters have been in use for more than 40 years.  Micro-inverters are still a fairly new technology, only in commercial usage for the last 10 years.  Central inverters are typically mounted on the side of the home near the main electrical panel, while micro-inverters are mounted on the back of individual solar panels on the roof.

The central inverter requires that panels grouped into “strings” or circuits.  If one panel in as string has shade that causes it to lose production, all of the panels in that string are also affected.  However, with a micro-inverter system shade only affects the single module being shaded; the neighboring, unshaded panels still produce at full power.  Each micro-inverter essentially manages its own solar module independently rather than in groups.

Similarly, the central inverter powers the entire solar energy system so if the inverter fails, the entire system stops working until the inverter is repaired or replaced.  If a single micro-inverter fails, the rest of the system is still working properly and producing power.

It should also be mentioned that a central string inverter usually weighs over 100 lbs and must be shipped via truckline (which  may take up to 1 week) and require at least 2  workers to replace it.  A typical micro-inverter weighs less than 5 lbs and can be shipped overnight and installed the next day by a single worker.

The most common question about inverters concerns the warranty.  Central inverters have a standard 10-year warranty and are typically a little less in cost depending on the size of the system; however, an extended warranty can usually be purchased.  Micro-inverters come with a 25-year warranty standard.

Finally, not all brands of solar panels are compatible with micro-inverters, due to their unique technology.  It is importnat to check with an experienced solar installation company who can recommend the best system for your needs, both in terms of equipment and financing.

Stellar Solar carries multiple brands of central sting inverters as well as microinverters and has been in business since 1998, supporting both commercial and residential solar energy system installation, so we can recommend the right system at the right price with the right financing for homes and businesses throughout San Diego.

 

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How Valuable is a PV Solar System?

We’ve all heard it before.

The benefits of adding a photovoltaic solar system to your home are innumerable, but one that you always hear is that it adds value to your home.

photovoltaic solar system

That should be obvious, as the systems are expensive and save tons of money, but the question of just how much value they add to your home has mostly remained unanswered, up until recently.

 In conjunction with Sandia National Laboratories, researchers at the U.S. Department of Energy’s Lawrence Berkley National Laboratory have recently completed the largest study on the effect of solar photovoltaic systems on home values in history.  Researchers more than doubled the amount of solar homes evaluated from previous studies, looking at around 22,000 home sales, 4,000 of which had PV systems.  In order to open up the scope of the research, researchers also looked at eight states outside of California where solar is not as prevalent.  Considering all these factors, the study is the most extensive of its kind.

The research determined that home buyers will pay about $4 per watt of installed PV, which averages out to about a $15,000 premium per home.  This value is averaged based on information gathered from housing busts, booms, and recoveries, so if projections are accurate, it should remain consistent.

The next step towards achieving this standard of value for PV systems is for realtors to be able to more accurately appraise homes with systems installed.  Hopefully, researchers will continue to improve valuing methods that realtors will adopt, and the value of PV systems will remain consistent and measurable.

 

Source: http://www.utilitydive.com/news/study-rooftop-solar-adds-15000-premium-to-home-values/352862/

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Solar Debate: Lease Vs. Loan

Third-party solar leasing has become very popular over the past three years.  Most of the national solar companies rely heavily on 20-year contracts such as solar leases or Power Purchase Agreements (PPAs).   These finance contracts are fairly simple to understand and easy for these companies to sell to customers who don’t know about better, less costly alternatives.  If a homeowner is not able to take advantage of the 30% federal income tax credit for solar, a lease or PPA may be beneficial, but that’s about the only time this is true.  In most cases, it is wise for solar customers to consider an alternative solar financing method.

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At Stellar Solar, we believe that owning a solar system is better for most people than leasing one.  So, we offer a financing called a “combo loan,” which (like the lease) requires no money down, but also allows you to take advantage of the federal tax credit; it’s called that because it’s really two loans in one.

 

 

  • First, your solar income tax credit (30% of the total price) is financed for 12-18 months at 0% interest, allowing you time to collect your tax credit from the IRS and then pay off this loan in full.

 

  • Next, the remainder of your solar energy investment (70%) is financed through a separate loan which extends for 12 years at 1.99% — with a fixed payment amount that is much less than your payments to SDG&E now.  Even better, there are no pre-payment penalties, so this loan can be paid off at any time. Most leases lock you in for 20 years of payments; the only exception is if you actually sell your home.

 

With this combo loan, you own your solar panels in 12 years rather than leasing them for 20 years.  There are no liens on your property (as with a lease), so you won’t have any hassles if you decide to sell your home.  With a lease, there are no guarantees that the next owner will want to take over your payments, but who wouldn’t want to own free-and-clear a solar energy system that drastically reduces or even eliminates their electric bill?

 

One seeming benefit of a lease is that the leasing company guarantees the solar equipment during the lease.   We agree that long-term protection against system problems is important, so we have contracted with American solar equipment providers that protect customers with a 25-year equipment warranty.

 

As the company voted the “Best Solar Panel Company in San Diego” by U-T readers for the past 3 out of 4 years, we believe this is the best solar financing program available, but you can be the judge.  Give me a call and I would be happy to put a custom solar proposal together for you.

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Photovoltaic Panels: How Do They Work?

While solar panels are changing the way people power their homes and businesses across the world, very few people know just how their solar panels work.  We have covered how solar panels power your home, but we have yet to ask: how do solar panels create electricity?

standard solar picture

Solar panels as we most commonly know them; the large, black, waffle-patterned panels, are actually made up of many photovoltaic energy cells linked together.  The individual photovoltaic cell (photovoltaic means sunlight converted to electricity) is made up of two layers of semi-conducting material, usually silicon, that are stacked on top of each other like a sandwich.  The top and bottom layers of the sandwich have opposite charges, positive and negative, which creates an electrical field.

In order to get the two layers of the sandwich to have opposite charges, the individual layers are doped with chemicals to change their charge.   The top layer is seeded with phosphorus which adds extra electrons, resulting in a negative charge.  The bottom is dosed with boron, which takes away electrons, resulting in a positive field.

Once the charges are established and the electric field is created at the junction of the two layers, the panel is ready to create energy.  When a photon of sunlight knocks an electron free, the electric field will push electron out of the silicon sandwich.  At this point, metal conductive plates on the side of the photovoltaic cell collect the electrons and transfer them to wires, allowing them become usable power.

via NASA.gov.

So solar panels are made up of giant webs of these photovoltaic cells, forming a photovoltaic system.  While individually their ability to generate power is minimal, when hundreds are linked together they are very productive.  If you have any further questions about how photovoltaics work check out NASA’s fully comprehensive explanation:  http://science.nasa.gov/science-news/science-at-nasa/2002/solarcells/.

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How Solar Power Works: An Infographic

Have you ever wondered how solar power works?

How those weird looking solar panels convert sunlight into power for your home? We at Stellar have found that many people are in the dark about how the process of using solar power for your home works, so we put together this simplified info graphic to help you understand:

 

how solar power works

 

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Michael Powers:  Solar Power Visionary

Stellar Solar Co-Founder Michael Powers was featured this week on the front page of the UT San Diego business section in an interview covering his extensive experience in and passion for the solar industry. Michael uses solar to power his home, his car, and his life.  Powers has been a huge proponent of solar energy since its beginning in San Diego in 2001, when Powers helped the first three Home Depot stores stock solar panels to be sold to the masses. 

Since Powers’ solar introduction in 2001, he has been on the cusp of the residential solar boom, building Stellar Solar, now one of San Diego’s top solar contractors, with his partners Kent Harle and Brian Grems.  Michael also runs a popular solar energy news blog and eNewsletter called “Terrawatts”, which is a trusted source of industry news for energy professionals.  He is a man who is passionate about solar, and who has made his living through pursuing that passion.

Recently the Union Tribune San Diego sat down with Mr. Powers and questioned him about the state of solar power and its future.  Mr. Powers is a professional at explaining not only how solar panels work, but also how they can save you money.  In the interview, Powers explains the “intermittent” nature of solar power, how when panels produce more power than needed, the extra power is received as a credit by SDG&E.  When panels are not producing enough power, the extra power needed is taken from the SDG&E credit so that it balances out the amount of power used but still costs the homeowner nothing.  Powers also spoke on the increasing amount of direct internet sales of solar, as now, he said, all that is needed is an electric bill and view of the home’s roof on Google Earth, and a quote can be written.  The days of solar contractors having to come out and look at the house to produce a quote are over, which is saving solar companies’ and their customers time and money.

With SDG&E renegotiating the way they bill and credit solar energy producers, Powers also encourages homeowners thinking about going solar to go ahead and make the leap: “anybody who buys a solar energy system between now and around 2017, they’re all going to be grandfathered in.”  Homeowners who buy their solar systems now will avoid the future costs involved with the SDG&E renegotiations.

Check out the full interview here: http://www.utsandiego.com/news/2014/dec/01/tp-solar-pitchman-sees-bright-future/3/?#article-copy

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The California Solar Initiative: The Policy that Helped Ignite an Industry

Despite the worldwide decline of solar energy installations due to the cutting of government incentive programs, one state’s program in particular has been extremely successful: Sunny California.  In fact, The California Solar Initiative, created by the state’s legislator in 2006 with the goal of putting solar panels on 1 million homes, was a gleaming success, exceeding their initial goal by hundreds of megawatts.  The program was scheduled to continue until 2016, but is being shutdown now, with it’s goals being far met two years early.
 
Unlike other countries’ solar incentive programs, California’s also worked in stimulating the birth of an industry.  Data from GTM Research reports that 74% of all solar projects in the state were completed without utilizing incentives in 2014.  It is estimated that California installers will deploy over a gigawatt of solar projects this year, most or all of which without the use of incentives.  
 
So what made the California Solar Initiative more successful than programs in other countries?  How did California get it’s residents hooked on solar?  The key to making the program sustainable from the beginning was using volumetric reductions in incentives.  Basically, the more megawatts deployed, the less payments given out.  This allowed the market to dictate the amount of money being spent, instead of having to rely on lawmakers to make a decision every time a change to the program was needed.
 
While the California Solar Initiative cannot be fully credited for starting the solar revolution in California, it did make financing solar a reality for thousands of households that otherwise would not have been able to afford it.  It has set California up to be on the forefront of cumulative solar deployment for the entire world, and sets an example for other US state governments on how to incentivize solar energy.  

 

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Solar Power Takes Flight in the Airline Industry

Solar energy is changing the way we power our airports.  Across the nation, states are turning to solar power to cut down on the operating costs and carbon emissions created by powering airports, an initiative that is not only helping the environment, but is also creating jobs.

Last Thursday government officials in Minnesota announced a $25 million solar project to be constructed at The Minneapolis St. Paul Airport, an addition that is anticipated to generate 20 percent of the airports’ electricity.  This move not only further solidifies Minnesota’s reputation as a leader in the the nation’s clean-energy policies, but stimulates the local economy as well by creating a slew of jobs.

The increase in the amount of airports turning to solar is due mostly to the airline industry’s sinking bottom line in recent years.  Energy stands as airports’ second largest expense, right behind personnel, and is so expensive that is causing most airlines to lose money each year.  Solar presents itself foremost as a money saver, which no one can argue with.

The environmental impact of the recent movement of airports moving to solar is significant as well.  The FAA estimates airports are currently reducing ozone emissions by 370 tons a year, the equivalent of removing 20,604 cars off the road.

So it’s clear why airports are turning to solar.  The obvious benefit of cost-effectiveness along with the positive effect on our environmental well-being is becoming too hard to ignore.  Hopefully, this trend of green airlines is indicative of a larger trend of big businesses switching to solar power.

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Solar Lease vs. Loan: Which Is Better?

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Solar power has never been more affordable, with plenty of financing options to choose from.

Many of the national solar companies rely heavily on 20-year contracts such as solar leases or Power Purchase Agreements (PPAs) which have become very popular over the past few years.

However, in most cases, there are other ways to finance a solar investment — such as the new 12-year, 1.99% Combo Loan – that can save customers a lot of money over the long haul and that’s why people are taking a look at them before taking the plunge into solar.

This also allows customers to take advantage of the 30% solar income tax credit, cutting their net cost by about one-third. (Read more here.)

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Solar Loans Now Available for Smaller Businesses and Non-Profits Through PACE Financing

Many small to medium-sized businesses would like to go solar to save money on their growing electric bills. Until recently, however, there was simply no financing available for smaller projects in either the commercial or non-profit segments of the market.

All that has changed, thanks to the new PACE program (Property Assessed Clean Energy) being offered in most areas of San Diego County.

Similar to residential PACE loans (also called “HERO” loans), PACE financing allows businesses and institutions that own property to borrow up to 20% of the assessed value of their properties for clean energy and efficiency projects, including solar.

Stellar Solar, voted San Diego’s Best Solar Panel Company by U-T readers for the past 3 out of 4 years, recently became qualified to offer PACE loans through Figtree Financing, a local lender based in Mira Mesa.

Because they often own their own properties, churches and other faith-based groups such as private schools can also take advantage of PACE financing to go solar and start saving on the energy bills immediately.

The best part about PACE loans is that the term can extend for up to 20 years with no money down and the projects are cash-flow positive from Year One. One small business in Mission Hills, for example, currently has an electric bill of about $1,225 per month; between energy savings and tax incentives, the PACE solar loan will generate almost $100,000 in positive cash flow in just the first 5 years alone.

Recently completed 73 kW PV solar system at First Unitarian Universalist Church of San Diego provides over 80% of the facility's energy needs. New PACE financing allows non-profits like this along with smaller commercial businesses to finance solar projects by leveraging property value.

Recently completed 73 kW PV solar system at First Unitarian Universalist Church of San Diego provides over 80% of the facility’s energy needs. New PACE financing allows non-profits like this along with smaller commercial businesses to finance solar projects by leveraging their property value to help reduce or eliminate energy costs.

For taxable businesses, PACE loans allow them to re-coup up to 40% of the initial project cost — in the first year alone –as direct cash flow from tax credits, depreciation and state rebate payments.

State solar rebates are expected to run out by the end of 2014 so many commercials properties are moving forward now to reserve these funds. Fortunately, with the PACE financing, projects generally remain cash-flow positive, even without the rebates.

Solar has always been a good investment, allowing people to save money while saving the planet. Now, PACE financing allows small-to-medium-sized businesses to take part while also making sure the business maintains a healthy cash flow for growth.

For more information on PACE solar financing for business and non-profits, please visit www.stellarsolar.net or email info@stellarsolar.net today!

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