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14 Things You Should Know Before Buying A Solar Power System For Your House
Saving money and doing something positive for the environment: these two reasons drive most homeowners to consider installing solar power. They’ve heard they can save money on their electric bills, and they know increasing the use of clean energy is a positive step for the planet. It’s not always easy to know where to begin. Some of the questions a homeowner might ask include:
Does my town/city/utility support the use of solar panels?
Is my home located in a good spot for a solar power array?
Would I have to fix my roof first?
How many solar panels would I need, and how much would an installation cost?
After considering the expense of panels and installation, how much money will I really save over time?
What type of solar panels would best suit my budget and needs?
The answers aren’t simple, and they vary depending on the location of a home; whether the roof does need a repair before installing solar panels; federal, state and municipal programs and solar power incentives; and the rates and policies of local utilities. That’s why it’s important to contact a qualified, professional solar installer—or even to talk to more than one – to request a site visit, a quote for panels and installation, and a savings forecast with a timeline for those savings.
Finding the Answers to Your Initial Questions
Many potential solar customers first do some research online. You can find information on local, state, and federal solar incentives as well as the average time expected for a solar array to pay for itself in your area. A professional solar installation company will send a sales representative who can explain the local, state, and federal incentives for installing solar panels in your area. In addition, he or she will understand your utility’s policies and will explain how your solar array will provide electricity to the grid, possibly yielding credits from the utility toward your electric bill (unless you are installing an off-grid system with battery storage that will directly power your home). After taking a look at your roof and the positioning of your home related to the sun and shaded areas, examining a recent utility bill to determine your average monthly power usage, and asking you what percentage of your bill you would like to offset with solar power, the installer will estimate the number of panels you will need. Often the installation company will send a professional roofer to determine if a roof repair would first be needed, and will take some time to design an array that would meet your needs before providing you with a final quote. Once you receive the quote and learn how much your electricity bill will go down on an average monthly basis, you can factor in tax and other incentives to estimate how long it will take your array to pay for itself before you start experiencing significant savings.
7. What Factors Affect the Number of Panels You’ll Need?
The question of how many panels you will need will be determined by your installer depending on a number of factors:
8. What percentage of your electric bill do you hope to offset with solar energy?
9. How much electricity do you use in an average month? (Consider potential future needs, such as electric car charging)
10. How much sun does your area receive?
The National Renewable Energy Laboratory provides a handy map that tells how many kWh (Kilowatt hours) you can generate in one year from 1 kW of solar panels if they are situated in an ideal spot in your area. Find their maps here: https://www.nrel.gov/gis/solar.html. Your installer will adjust for expected losses from heat, wiring, etc.
11. Does your state/utility offer Net Metering (credit on your electric bill based on the amount of electricity your panels feed into the grid)?
12. Will your installation include battery storage?
13. What is the maximum power output and efficiency of the solar panels you will install?
14. How many panels you need will depend largely on two main factors: power and production.
Solar Panel Efficiency Explained
When consumers evaluate solar panels, they often focus on the advertised maximum power (Pmax). This measurement represents a solar panel’s theoretical power production under ideal sunlight and temperature conditions.1 Think of it as the maximum amount of electricity a user can expect a solar panel to produce in an ideal solar environment. In truth, a solar environment is never ideal every day. Regional differences, as well as seasonal and weather changes, limit the value of the Pmax measurement when trying to determine the expected long-term performance of a newly installed solar array. It is important to consider the efficiency of a solar panel.
Solar Panel efficiency can be defined as the “Ratio of Solar Panel Power and Size (W/m2 ); at Standard Testing Condition” (STC). Universally, STC is measured as 1,000W/m2 of sunlight, temperature of 25 deg C, and air mass of 1.5.
Below is an example of efficiency calculations for 60 cell and 72 cell:
LG NeON® 2 panels: NeON® 2 60 Cell: STC Power Rating- 340W/0.34kW;
Length – 1.686m; Width – 1.016m
• 0.34kW / (1.686*1.016)m2 = 0.34 / 1.7129m2 = 19.8% Efficient
• Panel Power (in kW) = 0.34
• Length (in meters) = 1.686
• Width (in meters) = 1.016
NeON® 2 72 Cell: STC Power Rating- 405W/0.405kW; Length – 2.024m; Width – 1.024m
• 0.405kW / (2.024*1.024)m2 = 0.34 / 2.0725m2 = 19.5% Efficient
• Panel Power (in kW) = 0.405
• Length (in meters) = 2.024
• Width (in meters) = 1.024
LG NEONR
Armed with the knowledge of a panel’s efficiency rating, consumers can determine reasonable expectations of the performance of their installed solar systems in different sunlight conditions. Utilities and homeowners who want to maximize the amount of electricity generated by their solar systems should always choose high efficiency panels. High efficiency panels purchased at a good price represent the best value for solar customers. The added efficiency means fewer panels are required to generate the same amount of energy.
Energy Efficiency Estimated
LG Solar and High Efficiency Panels
The efficiency rating of a solar panel varies by manufacturer and panel type. LG Solar’s goal is to manufacture high efficiency panels that will provide LG customers with a solid return on their investment.
What this means is that LG Solar’s panels produce more watts of electricity per watt of sunlight than solar panels with lower efficiency rates (most conventional panels on the market today). LG Solar is constantly innovating new technologies that boost our solar products’ output and efficiency.
LG NeON® 2 BiFacial Panels and Double-sided Generation
LG Solar’s 72 cell BiFacial solar panels are a commercial product designed to absorb irradiance from both the front and back sides of the cells thanks to a transparent back sheet. The dual faces of the cell allow for higher energy generation. The increased kWh/kW leads to a faster payback time and return on your investment.
The reactiveness of the surface on which the panels are installed can help boost output and efficiency.
NEON2-BIFACIAL
The NeON® 2 and Cello Technology™
The NeON® 2 is LG Solar’s best-selling solar panel, thanks to its high efficiency rating along with high power output, outstanding durability, and aesthetically pleasing design. But how is its efficiency rating achieved?
LG Solar’s NeON® 2 panels incorporate a technology called Cello (Cell connection with Electrically Low loss, Low stress and Optical absorption enhancement) Technology™. Cello Technology uses 12 circular wires in each cell instead of the usual busbars. The circular wires scatter light effectively, improving light absorption. Then, the 12 wires reduce the loss of electricity because of the increased number of pathways available to absorb electrons. These additional pathways for the free-flowing electrons translate to more electricity produced per absorbed watt of sunlight—and that means higher efficiency levels.
Also thanks to NeON’s cell characteristics, the panels are highly efficient even in low-light conditions, such as mornings and evenings.
The NeON® R and Back Contact Technology™
The NeON® R is LG Solar’s high-power luxury panel featuring up to 21.4% efficiency thanks to our newly developed Back Contact Technology. The advanced cell structure of the NeON® R locates all of the panel’s electrodes on the back side, reducing power loss resulting from shading. This boosts the panels’ capacity for light capture and overall efficiency.
As with the NeON® 2, the electrons absorbed by NeON® R panels are funneled into numerous pathways instead of the usual three to reduce power loss and increase power output.
Conclusion:
Why Efficiency Matters?
When homeowners consider their choice of solar panels, they look at a variety of features, from aesthetics and durability to maximum power output and warranty policies. Efficiency is one of the most important considerations. High efficiency panels produce more power in a smaller space over a variety of sunlight conditions. As a result, fewer panels are required to produce the same level of power output (which gives installers more flexibility when designing arrays for smaller roofs or in shaded areas).
Balancing the investment in the cost of solar panels with their efficiency rating and maximum power output, consumers gain both short-term and long-term benefits from purchasing high-efficiency solar panels. LG Solar’s BiFacial, NeON® 2, and NeON® R panels provide solid options for arrays ranging from small rooftops to large commercial installations.
_ Provided by LG Solar
A Journey To A Net Zero Energy Home
Solar Panel System with Battery Storage
As the extreme weather event such as heatwaves, hurricanes, floods, wildfires, drought, and rising sea levels is emerging, rooftop solar panels offer an affordable solution to restore natural systems with renewable, carbon-free energy. Distributed solar offers tremendous potential to reduce our nation’s GHG emissions, and large deployments will also reduce sulfur and mercury pollution while saving approximately 60,000 American lives each year.
One remarkable net zero energy project that had a positive impact on the community, the environment, and our company is the Starkey solar project.
Background
Gil (James) Starkey is co-founder of 350 Austin, a nonprofit organization fighting the climate crisis. He has dedicated his energies to inform people about global warming while personally taking on the climate crisis by shifting his reliance away from fossil fuels and moving toward clean energy with rooftop solar, a battery system, and a fully electric vehicle.
Starkey and his wife Roberta Tsurkahara have been interested in solar and energy conservation for a long time. They had solar on the home prior to their move to Texas and were familiar with the benefits when they purchased their new home in the Mueller neighborhood. Installing another rooftop system seemed like the right thing to do. They have owned their current system for three years now and are contributing to a more fossil-fuel-free world.
Since their home was newly built, they were not certain what their energy needs would be, but they wanted a photovoltaic system projected to offset over 90% of their consumption. After some discussion and number crunching, they concluded a 7.5 kW system would be a good fit. The system produces an average of 10,705 kWh yearly by utilizing 25 LG 300W AC modules. However, the Starkey family has managed to consume less electricity than the average home of its size. The result is they produce more electricity than they use and the family has yet to pay an electric bill.
This year, with federal incentives scheduled to decline in 2020, the Starkey’s decided to make their next big investment by purchasing an electric vehicle and a battery system. With two Tesla PowerWall batteries, they can manage their entire home electricity consumption and monitor their usage. Battery storage is another tool that helps the Starkey family deal with climate change and manage their way through blackouts.
Tesla
Power
Wall
& EV Charger
Customer Interview
I had an opportunity to ask Gil a few questions about his solar journey.
Nafi: What interested you about going solar initially?
Gil: Having lived most of my adult life in the Boston area, we had no real opportunity for solar power, since we lived in urban condominiums. These buildings ranged from 70-110 years old and were difficult at that time to retrofit for solar. I became interested in solar when I moved to Austin in 2000 and built a house. Our interest at the time was to limit, as much as possible, our direct impact on the environment. Generating our own electricity was, therefore, appealing.
We were not able to implement solar before returning to New England, this time to an ecovillage in Maine. We installed solar there for the same reasons we had planned to do so here in Austin. By the way, we were in mid-coast Maine, where wintertime overnight lows are quite frequently below zero, often 10-15 degrees below zero. Our house was designed to approach the Passive standard, so it was extremely well insulated and faced solar-south to maximize passive heating. Because of these factors, our home had to be, and was, 100% electric, even in a frigid climate. Our solar panels enabled us to live very comfortably at nearly net-zero. That experience sold us on solar panels.
By the way, solar panels were cropping up all over Maine on 100 to 150-year-old farmhouses. I was surprised to learn that although Maine receives much precipitation and experiences many cloudy days, it actually receives more sunshine than Germany, where solar panels are ubiquitous. No wonder Mainers, thrifty New Englanders that they are, were installing solar!
Nafi: How did you choose a solar installer?
Gil: Having already decided to go solar once we returned to Austin, I began researching companies as soon as we knew where we were going to live. My research narrowed things down to a few companies and my decision was confirmed when I discovered that our neighborhood had gone through a selection process for a significant solar project a year or so before we moved in.
Nafi: What advice would you give to someone who wants to go solar?
Gil: First of all, it just makes sense from economic, environmental, and climate change perspectives. Texas is absolutely bathed in sunlight. I am baffled that governments and electric utilities do not promote and subsidize solar more strongly. The more solar people install, the fewer utility-grade power generation facilities must be built, and that alone will save utilities hundreds of millions of dollars.
The price continues to plummet. Two years after installing solar in Maine, we purchased a system here that was 40 percent larger, but the net price of the two systems was the same. We (humanity) must move to a zero-carbon economy at warp speed. Global heating is approaching tipping points that once crossed, cannot be reversed. Utilities have traditionally contributed the most greenhouse gases, so widespread solar (and wind) generation is a necessity. It makes sense. Do your research. Find a strong, reputable company, and get a proposal.
Nafi: Do you have any data on your solar system’s performance you found it interesting to share?
Gil: Our system was intentionally over-engineered because we planned at some point to purchase an electric car. We now have our EV, and I am pleased to report that our solar array is supplying all of our home's electricity, even in summer, plus charging the car. We are effectively off-grid for home and transport. Since installing solar in February 2016, we have not paid any utility bills. That’s right, $0, and we have a substantial credit with Austin Energy.
Without a rooftop solar system, they would have paid approximately $1,243 per year for the electric bill. Moreover, the solar panel system cost will be paid off within 8 years and the total amount of money the household will save within 30 years is estimated at $41,785.
Net Zero Energy Home: Austin,Texas
Solar+Storage Data Monitoring: a Strong Tool to Manage Usage
Everyone is familiar with data collection trends and the ways in which information is used and misused; from sabermetrics in baseball to news blasts on Facebook. But when it comes to conserving energy in your home, energy monitoring tools are extremely useful. These tools are available for consumers to monitor the production of their photovoltaic systems and the energy consumption of their home or business.
The ability to see and use consumption data enables the Starkey’s to make informed decisions about their electricity use— knowledge is power when it comes to conserving energy. Online monitoring tools enable customers to access information from their browser or smart phone. After three years of monitoring, the Starkey system has offset 100% of their home electricity consumption. This could change next year with the additional EV home charging load; time will tell.
The graph illustrates the electricity generation and consumption for two summer days related to the Starkey family solar system. Despite the higher consumption in the summer time and using an EV charger the production still matches what the household demands.
Conclusion
The United States installed 2.7 gigawatts of solar in the first three months of this year, which set a record for the first quarter of a year. In addition, 25 percent solar growth is predicted this year by Wood Mackenzie Power & Renewables institute. According to Renewable Energy World Texas holds great potential to increase renewable energy generation and to integrate distributed solar resources in innovative ways while preserving our deregulated market structure. Collective action is all that is required to move and make Texas green.
If you would like to learn more about Lighthouse Solar services or be a part of the green movement, contact us at Lighthouse Solar for a free estimate and consultant.
Click HERE or call us at (512) 476-5555.
- By Nafi Shah & Jay Bramble
Attention Austin Energy Customers!
Lighthouse Solar
August 31st is the last day to secure the Austin Energy $3500 summer rebate!
Are you surprised by your summer electric bill? July has been the earth’s hottest month on record. Solar panels are the best tool to combat a high electricity bill and save money.
If you’ve been waiting to go solar, now is the perfect time! Austin Energy (AE) solar incentives can go a long way to make solar affordable. Austin Energy provides a chance for its customers to get a $3,500 rebate when they install a solar system on their home. In addition, you are eligible for a 30% Solar Tax Credit from the Federal Government - which is dropping to 26% in 2020. Don’t lose your chance to maximize your savings by installing a qualifying solar photovoltaic (PV) system on your home. The Austin Energy $3,500 rebate will expire on September 1st Installation is not required by this date. Rebates can be secured through a letter of intent with Austin Energy. Contact us to show you how.
Support sustainable green solar energy:
To Save Money & Reduce Your Electricity Bill
To Protect the Environment and Keep Austin Green
Strengthen Our Local Economy by Creating Clean Energy Jobs
Reducing Your Electricity Bill
Help Grid Demands During Peak Hours
At Lighthouse Solar our sales/design team will generate a customized proposal for your home!
If you’re interested in getting a free solar consultation call us at (512) 476-5555 or click on the button.
_ Nafi Shah
Communication Coordinator
LighthouseSolar
Essence of Solar Financing
I have had a lot of conversations about how solar financing works and how it varies from traditional financing. Solar financing can seem a bit strange and unfamiliar so I decided to jot down some facts and hopefully explain some of the basics.
No money out of pocket
Every single loan product we offer for solar system is NO MONEY DOWN. This means no upfront costs or fees. Essentially you can transition from paying the utility to rent your energy to owning your energy without spending a penny!
Flexible to Meet your Needs
Solar financing is available in many terms making it easy to tailor the loan to the project and/ or the clients particular budget goal. Our lenders offer 10, 12, 15, and 20 year terms. All solar loans are simple interest and have no pre-payment penalties.
Caters to Federal Solar Tax Credit
This is the meat and potatoes of solar financing and what makes it different from traditional loans. When you purchase a solar system, you can receive a 30% refund of the system’s cost on your next federal income tax return. Solar financing takes this incentive into consideration in the payment schedule.
When you finance your system the loan is set up to give you up to 18 months to file your taxes and apply the 30% Solar Tax Incentive to the loan. The finance contract will include 3 different payment amounts. The first payment is an interest-only payment for the period of time (up to 18 months) in between installation completion and when you file your taxes for that year. The second is the payment amount before the incentive is paid to the lender and the third reflects what the payment will be after the 30% has been paid. This allows you to have enough time to file your taxes and forward the payment to the lender.
Payment of the 30% federal tax incentive is not required by the lender, nor is there any penalty if it is never paid. You simply would have a higher payment based on the principal loan amount being 30% higher. It is worth mentioning that close to half of people who finance their solar systems never pay in the incentive. Some use the 30% tax incentive to pay down other higher interest loans or credit cards. Others might take a well-earned vacation or make a larger purchase that may have otherwise been impossible. It is a good example of how solar has hidden benefits beyond the obvious energy cost savings.
To sum it up, there is a financing option for everyone and we cater to each client individually and offer options in a consultative manner.
-Erik Smith
Technical Sales
LighthouseSolar
Our Take On The Tesla Rooftop Solar Panel
We’ve been hearing a lot of buzz in the industry surrounding Tesla’s recent announcement of the “Tesla Solar Roof” product. Being designers and installers of solar technologies we wanted to share some of our thoughts on this product announcement and hopefully clear up some of the questions and confusion left by the announcement event.
Previous Attempts at Integrated Solar
Firstly, the concept of a solar integrated roofing shingle is not entirely new. It has been attempted previously by several manufacturers in the residential market including some big industry players like Dow with their Powerhouse shingle, and Sunpower with their SunTile product. Both products underwent significant marketing efforts and the building out of dealer channel networks, but ultimately were met with limited success in the market and discontinued.
For those with a negative view of the aesthetics of solar panels, there is a clear advantage to using an integrated roofing shingle product. Others, however, find the look of roof mounted solar panels quite beautiful and see their addition as an upgrade to the home’s overall aesthetic.
Points to Consider:
Power output: Tesla has not yet said much about the technology behind the “Solar Roof” product, but historically PV roofing shingles have utilitized less efficient “thin film” solar technologies which would require far more roof space to achieve the same system power when compared with standard, framed PV modules. Even if the end product uses a higher-efficiency PV cell, the fact that the cells will be spread across individual shingles will again cause a decrease in array efficiency since they cannot be packed as tightly onto the roof. Furthermore, these cells and shingles will be installed directly on the roof’s surface which will cause them to operate at a higher temperature. Standard PV panels utilize racking systems which allow for air to flow below the array, thereby cooling the cells. The power output of PV cells is reduced as cell temperature increases, so this cooling effect is very beneficial.
Maintenance: For a PV array to operate efficiently it needs to be capable of moving electrons from all of the PV cells making up the array into the home’s electrical system where they are utilized. This requires thousands of electrical connections. In a standard system most of these connections exist within the solar panels themselves and are protected by the glass face, aluminum edges, and insulating backsheet of the panel. The panel-to-panel connections and those into the house are made with highly durable locking components and wire tested to stand up to harsh, outdoor conditions. In PV shingle products each shingle needs to be electrically connected to the shingle next to it, and for this to remain relatively flat will require those connections to be more fragile than those utilized to interconnect standard PV panels. Also, when one of these fragile connections breaks between two shingles, imagine the task of standing on a roof covered with thousands of shingles and trying to troubleshoot and isolate where that problem is located! The modular nature of a PV system built with standard modules makes it relatively easy to determine where a problem has occurred and, if need be, replace a panel or a section of wiring. Lastly, once this solar shingle roof is installed and functioning the smallest change to the roof to add a vent, chimney, or change the roofline for any reason becomes extremely complex and costly.
Cost: If one were to ignore the maintenance issues with this type of product, it could be argued that cost-competitiveness could be achieved in a new home construction scenario or possibly a re-roof. Many homebuilders, however, will not want to risk the reliability of a new roofing product nor the need establish relationships with new sub-contractors in the conservative roofing installation market. Regardless the solar shingle will most likely cost more than standard roofing plus solar panels combined, will require a more expensive installation procedure, and as noted above, will incur a higher cost of maintenance across the system’s lifetime due to lower overall reliability. When working with roofing companies on Dow solar shingle projects we saw turnkey system costs that were over 400% higher than standard solar PV system costs.
Elon Musk has great vision, is a clever marketer, and certainly has done well to produce a high-quality electric car. With that being said, we will withhold final judgement on the Tesla Solar Roof until technical specifications and pricing are released, but certainly have concerns about Tesla’s ability to get this product to market and find a place for it to be competitive against the increasingly efficient, reliable, and cost-effective mainstream PV market.
Interested in going solar? Speak with our Austin solar panel installation experts at Lighthouse Solar to get started with a free consultation.
How Can Net Metering Benefit You?
Net Metering is a system that allows you to send the excess electricity your system produces back to the electricity grid and receive credits that can then be applied to your utility bill.
Without net metering, a homeowner must pay for the electricity they use at night, when the cloud coverage is too dense, or when snow is covering their panels. With net metering, a solar panel system can be installed that can cover the entirety of a home’s electrical needs because the system does not need to be producing the exact home usage in real time 24 hours a day, 365 days a year. Of course, that kind of real time production would be impossible due to weather and daylight hours.
HOW DO YOU COLLECT CREDITS?
When you install solar system on your home, your panels produce DC (direct current) power, which is sent through an electrical converter called an inverter. An inverter converts the DC power to AC (alternating current) power that can be used by your house. Your house uses the AC power and any excess power is sent out to the grid to power other neighboring homes.
As the excess power leaves your home, your power meter credits you for this power by spinning backwards instead of forwards. These credits are then applied in full retail value as you draw from the grid at night, or in the winter months, when your panels are not producing enough to cover your usage.
HOW IS NET METERING MEASURED?
Net metering is measured over a year. If you have a system that is designed to produce 100% or more of your annual usage, your installer sizes the system to produce an excess in the sunnier months to create a supply of credits to be used in the winter months. If you produce more than your usage during a month, your utility bill will show your credits that roll forward to the next month.
If your solar system produces less than your usage during a month, you pay the difference (after credits are applied) to the utility. At the end of a year, if you have produced more power than you have used, your utility will convert the credits into a refund check at the wholesale rate (which is much lower in value than the retail rate). This is called the Anniversary Month. You may change your Anniversary Month one time with the utility. It makes sense to have your Anniversary Month in the spring because you start collecting credits in the sunnier spring and summer months that can then be applied through the fall and winter. It is more valuable to use your credits for electricity (retail value) than to be refunded for them at the end of the year (wholesale value).
Your electricity bill will never be $0 because you must continue to pay a monthly connection fee to the utility in order to remain connected to the grid. This fee is under $25 and supports the utility infrastructure in your community, which you use for net metering, sending electricity out to the grid and pulling electricity from the grid.
Interested in going solar? Speak with our Austin solar panel installation experts at Lighthouse Solar to get started with a free consultation.
The Seasonality of Solar Energy Production
As an owner of a solar system or when considering going solar, it’s helpful to understand what your system will output over the course of the four seasons. Here in the northeastern United States we do see significant variation in daily energy output from our systems over the course of a calendar year.
SPRING AND FALL
Based on real data from the Lightgauge monitoring systems we install for our customers we can closely track each system’s energy output variation during the year. If we split the year into two equal parts at the Vernal and Autumnal Equinoxes (March 21st and September 21st) we can get a quantitative handle on this variation. It turns out that, on average, 65% of our local solar system’s annual energy output is generated between March 21st and September 21st of each year. The other half of the year, between September 21st and March 21st, accounts for the other 35% of annual output.
SUMMER AND WINTER
Furthermore, if we take a look at the two month windows surrounding both the Summer and Winter Solstices (June 21st and December 21st) by comparing system outputs for June and July vs December and January we can further accentuate the seasonal variation. On average our residential solar customers see a total energy output decrease of 40-60% during the months of December and January as compared to July and August.
The factors involved in this variation are threefold.
Firstly, we know that in our area we have shorter days in the winter than we do in the summer. This means that the solar system will be running for less time each day and therefore produce less average energy per day.
Compounding the effect of the shorter days is the fact that the sun angle changes dramatically in the winter as well. The sun, even at it’s peak around midday, is much lower in the sky during the winter months. For most residential rooftops this means that the sun’s rays will be hitting the solar panels less directly than during the summer months. This will cause the system’s power output to be lower which also has a direct impact on energy production.
Lastly, atmospheric conditions need to be considered. Not only do the winter months provide plenty of stormy weather and cloud cover, but the effect of snow cover on the panels after a storm is significant as well. With a thin covering of snow the system will often still be able to turn on and output a small amount of energy. Larger snow accumulations on the panels, however, can keep the system from converting energy for up to a few days until the panels clear.
IMPACT ON UTILITY BILLS
So how does this work with your utility billing? Won’t this cause system owners to get high electricity bills all winter long when their systems are under-producing and their usage is increased due to more time in the house, higher lighting loads, etc.? Not necessarily, and this is where net metering comes into play. When we design solar systems for customers we always look at the total annual electricity usage when sizing the system. For customer’s with adequate roof space (or area for a ground mount) this allows us to design a system which overproduces enough during the spring, summer, and early fall to build up a bank of kilowatt hours with the utility which will carry the homeowner through the winter months. Thereby the effects of reduced energy production during our northeastern winters can in fact be mitigated through correct system design, sizing, and net metering (read more about net metering here).
This is also why, for our customers who get their systems interconnected in months other than March and April, we advise them to utilize their utility’s “Anniversary Date Change” process to make sure that they are optimizing the use of their net metered energy credits over the course of the year.
If you’d like to learn more about optimizing your anniversary date please call our office and speak with one of our Technical Sales Engineers.
Interested in going solar? Speak with our Austin solar panel installation experts at Lighthouse Solar to get started with a free consultation.
What Else Can Solar System Do?
Given the number of installations we are performing to meet customer demand, it is easy to forget some of the powerful opportunities solar has for many of our customers. Solar is inherently modular, which leads us to think that every system is a slight variation on the same technology, values and long term impacts.
It is refreshing and very exciting when we can demonstrate through effective collaborations and a listen first approach that the integration of solar systems into our built landscape has immediate and latent effects that far exceed the obvious and measurable benefits of clean power, on site power, emission free power and water free power.
A project example illustrates this point clearly.
Several years ago, LighthouseSolar won a commission and ultimately an IREC design award to design and install solar classrooms at 15 middle and high schools in Austin, TX. We collaborated with Austin Energy, Austin Independent School District, and a curriculum developer to deploy a solar classroom at each location for the student and teacher communities to use.
To inform our design approach, we asked the question: What would it look like to have Stonehenge meet the IPhone? We are guided by the fundamental principles that solar is also technology of mythic proportions and eternal time scales, yet we live in a world enabled and pressurized by technologies of instant and distributed connectivity.
For this, our solar classroom needed to serve both real design guidelines.
First, the solar classroom is monumental in aspect. Not that it is so big that is can’t intimately hold the attention of a small class of students, rather it is informed by systems scaled beyond our local experience. The movement of the sun is an experience shared by everyone on earth and while each location on earth has a slightly different experience it is worth remembering that a Greek geographer, Anaximander, calculated very closely the circumference of the globe by looking down a well in Egypt. The global is in the local. This sort of expansive curiosity is available upon casual but pointed interest in a solar system. Our classroom makes this more apparent due to the design elements. The structural supports align with the altitude of the sun at the summer solstice. The depth of the room is defined by the lowest sun angle at the winter solstice. Sun angles are also reflected within the tapered angle of the bench foundations that ring the classroom. The student can feel the shape of the solar ecliptic through their feet.
This brings us back to the power and breadth of the connectivity that the iPhone generation is growing into. The expansive question occurs to us: What will the generation look like and be capable of having experienced the sense of the sun coupled with the tools that hand held computers offer? It is more exciting in what is possible than what is quantifiable.
The solar classroom is also equipped with tools of the modern era. Electronic teaching tools, QR Codes, skype conferencing, weather data monitoring and solar production monitoring set up the ability to run experiments, track results and test hypotheses. These are also tools of sharing, global connectivity all in the context of primary education.
Solar energy is more than a commodity, more than an economic opportunity and more than a switch in the dominant energy paradigm. If culture is where science and imagination meet, then perhaps solar holds a deeper proposition to recast our culture in ways that we are yet to discover.
We continue to ask the simple question: What else can solar do? We invite you to inquire accordingly.
Choosing The Right Inverter for Solar Panels
One of the most important questions to ask when designing a solar array is, “What type of inverter does the system need?” Which inverter will provide maximum production for the best price?
Every grid connected photovoltaic (PV) solar system needs an inverter. It’s the brains and the brawn of the system, the integral piece of equipment that takes the Direct Current (DC), being produced by the solar panels, and inverts it to an Alternating Current (AC) which can then be used to power your appliances and interact with your local electrical grid, AKA, your utility company. The inverter is the workhorse of the system and does a majority of the heavy lifting.
Although there are many companies from all over the world that produce them there are only a few types of inverters including central inverters, string inverters and micro inverters. Since central inverters share many similarities with string inverters and are more often used in commercial and utility scale projects, we’ll focus on the two types that comprise a majority of residential solar systems, string inverters and the module level power electronics known as micro inverters.
Simply put, string inverters allow panels to work together as a unit while micro inverters allow the panels to work independently. Let’s look at them in more detail.
Micro Inverters
A micro inverter is exactly what it sounds like, a tiny inverter. They are small enough to attach one to each and every solar panel in the array, allowing them to operate independently from one another, converting the electrical current from DC to AC right at the panel itself. Micro inverters allow the panels of a system to work optimally under less than perfect conditions.
If you look at a satellite image of your neighborhood, you’ll see that roof tops come in all shapes and sizes. Some are big and simple while others resemble MC Escher lithographs, with multiple arrays of varying size pointed in different directions.
In situations like the latter, a micro inverter would be the best option. The presence of large objects that will cast shadows such as chimneys, tree limbs or even your neighbor’s house might also benefit from installing micro inverters. Remember, as the Sun moves across the sky, shadows will move across your solar array. Also, a shadow that exists in December may not be present in July. Any situation where, at any given time, a panel will be shaded while other panels are receiving direct sunlight would be a perfect situation for a micro inverter.
Imagine that your roof is comprised of many small arrays, multiple hips and valleys all aimed in different directions. Right in the middle is a chimney casting a shadow that moves across the plane throughout the day. When one section is getting direct sunlight, another is just receiving a glancing blow. When one panel is stuck in the shade of the chimney the panel next to it is getting kissed by the Sun. This scenario is easily solved by installing micro inverters to each and every panel. With micro-inverters, if one panel is basking in direct sunlight it’s not in danger of being slowed by another panel in the array that is hiding in the shade.
String Inverters
Now picture one big, open space to place an array of solar panels. This could be a large section of roof or even an open field on your property where you could place a ground mount. All of the solar panels in the array can be placed side by side and there are no objects such as trees, chimneys or satellite dishes that might cause shade. All of the panels will be under the same conditions. This would be a perfect environment to employ a string inverter.
String inverters come in different sizes and wattages. In a string inverter system, all of the panels send their DC current to a single inverter which will invert the entire load to AC. They are efficient with fewer moving parts and fewer possible points of failure than their micro counterparts. They can be used individually or in different combinations to match the size of any system. The panels can be configured onto two to three separate strings per inverter allowing for a certain amount of flexibility as well as increased efficiency. String inverters also come with two distinct advantages.
First, rather than being placed on the roof, the hottest and least accessible part of the house, the string inverter will be placed right next to the utility meter. It will be in the shade, which will boost efficiency, and will be easily accessible for any possible service. The second advantage is a lower price tag. Generally, a string inverter is a less expensive option than micro inverters, and saving money, along with reducing your carbon footprint and championing the environment, is one of the primary benefits of making the move to solar.
Optimizers
A hybrid alternative would be to use an optimizer. Optimizers can be used in conjunction with a string inverter and are placed on individual panels that might be affected by shade throughout the course of a day. If a part of the array is affected by shade the optimizer will adjust the output of the affected panel, saving the other panels from being slowed down in the process. Then, when that panel comes into full sun, it will readjust the output and re-engage with the other panels at full power. Optimizers can be added to a system even years after the initial installation as shade from growing trees begins to affect the production of the existing panels.
In short, going with the right inverter will allow your system to perform at its peak potential. Beware of salesmen or installers that bid only one type of inverter or even one brand of panel, claiming that their product is “the best” or the “most efficient”. What that usually means is that they only have one option available to them and they are trying to sell that product as the best for all situations. Your home and even your energy usage is unique and there is no one-size-fits-all solution. As always, a little homework goes a long way. Read some reviews, get proposals from several qualified installers and go with the company that will design an efficient and cost-effective solar system around you.
Our Consumption Habits
Invariably, the first 2 questions we receive when introducing solar to folks are the same:
How do the panels handle hail? (we are in Texas afterall)
What would it cost to run my 2000 square foot house?
The answer to the first is that the panels are warranted against a direct impact of
1” hail and the incidence of damage is miniscule.
To the second question, we reluctantly but accurately have to answer, it depends. This is not a dodge, a sheepish sales tactic or our lack of understanding. It is quite accurate and must follow with an investigation of what the customer’s energy consumption actually is. This is where it gets quite interesting.- sometimes pandora’s box kind of interesting.
To refresh, there are some basic principles that inform this conversation. In the solar industry we are used to talking about power and energy as very distinct phenomena. In common parlance, things get overlapped and often lead to confusion. Think about the difference between an energy drink (like Red Bull, astimulant) and an energy bar (often a source of protein). The terms are confusing. She is a powerful leader, he has good energy… We characterize our experience in these terms very often.
In the context of electricity and specifically as it relates to your home, it is very specific and needs to be kept distinct. Think of a light bulb. A 13 watt LED bulb draws 13 watts of power the instant you turn the switch. And it continues to draw that amount of power as long as the circuit is intact. That’s power: 13 watts. Now run that bulb for an hour- you get 13 watt hours. That’s energy. 13 Wh. When you take a look at your residential bill, you are charged in units defined at kilowatt hours (kwh) That’s a lot of LED bulbs by the way.
As you go around your house you can add up the power you may draw as individual circuits or appliances are turned on. You can just talley them up. There are many that may escape attention (ghost loads), because there is not much going on visibly, yet there is still power being drawn. Your TV likely is drawing power to stay warmed up so that is comes on instantly when you want it. Be thorough to take stock.
And then there is energy and this is the key metric for most residential settings. It is a combination of the power you are drawing and for how long. As you use more power your consumption goes up, but more impactfully, the longer you run those loads, the more your energy consumption goes up.
Now there is no real magic here. Running your whole house for 1 hour is the same energy consumption as running 1/24 of you loads for 1 hour. But the rub, is that no one manages their household this way and better said, it is quite rare for folks to manage their household from an energy perspective that is thorough and time based. We have grown up not really concerned with that or equipped with the right tools to see what the actual effect our habits have on energy consumption.
Like many of you, I grew up with the blanket admonitions to turn lights off, don’t waste energy, all the while I had no real conception of how the walls that surrounded were managing heat, or how efficient the appliances really were. We believe, management does not hinge on guilt, but can thrive when one is equipped with tools to visualize in real time how much power and energy we are using. For this we install Lighgauge Monitoring on all of our solar system and even on building with no solar. You can see, at circuit level, what you are using and where the energy is going.
And this gets us back to our first, or second, question. How much does it cost to run my 2000 sf house with a solar system? While I will unpack other dimensions of this question in a following blogpost, we much first recognize that the house is specific, you habits are specific and the way you manage your habits in your house are even more specific.
So we begin to inquire, analyze and recommend how your habits measure up to your expectations or even to general averages. In the end, we can speak confidently from a set of regional averages and rules of thumb, but that partly misses the point, that our experiences are all our own. Our habits needs to be recognized. The solar system we will design and implement for you is specific, even though it draws on the generous, available power of the sun, your solar system will be an integral part of your experience, which is inherently unique and tailored.