Introduction
Harnessing the sun’s power has become more than a clean energy alternative; it’s a transformation in how we power our lives. Solar photovoltaic (PV) systems are at the forefront of this revolution. This comprehensive guide will illuminate the essentials of solar PV systems, helping homeowners understand the pivotal steps and components involved in turning sunlight into electricity.
What is a Solar Photovoltaic System?
A solar photovoltaic system, commonly known as a solar panel system, is a power system designed to convert sunlight directly into electricity. It consists of an arrangement of several components, including solar panels, inverters, batteries, and other electrical accessories, working together to harness and utilize solar energy.
Key Components
- Solar Panels: The most visible and essential parts of a solar PV system. They are responsible for capturing sunlight and converting it into direct current (DC) electricity. Solar panels, or photovoltaic cells, are the heart of the solar PV system. Made from semiconductor materials, they capture sunlight and initiate the photovoltaic effect, which generates electrical current. Panels come in various types and efficiencies, including monocrystalline, polycrystalline, and thin-film, each with its own set of advantages and cost considerations.
- Inverter: This device converts the DC electricity generated by the panels into alternating current (AC), which is the type of electricity used in homes. The inverter is a critical component that serves as the bridge between the solar panels and the home’s electrical system. It converts the DC power produced by the panels into AC power, which can be used by standard home appliances or fed into the electrical grid. Inverters can be centralized for the whole system or individual microinverters attached to each panel.
- Batteries (Optional): Batteries can store solar power for use during nighttime or on cloudy days. Solar batteries enhance the solar system’s functionality by storing excess energy produced during peak sunlight hours. This stored energy can be used when solar production is low, such as during the night or on overcast days, ensuring a consistent energy supply and reducing reliance on the grid.
- Mounting System: This includes the structures that hold the panels in place, either on a rooftop or on the ground. The mounting system securely anchors the solar panels to the roof or the ground. Roof mounts are the most common in residential installations, while ground mounts are used when roof conditions are not ideal. The mounting system must be engineered to withstand environmental factors like wind and snow loads.
- Electrical Accessories: Various components such as wiring, switches, and meters are used to safely transport and monitor the electricity produced. These encompass all the additional electrical components that ensure the safe operation of the solar PV system. This includes conduit and wiring that connect the panels to the inverter, safety disconnects that allow the system to be powered down for maintenance, and meters that measure the production and usage of electricity. Proper sizing and installation of these components are crucial for both safety and system efficiency.
How Does a Solar PV System Work?
The process begins when photons from sunlight hit the solar panels. The panels then convert these photons into electrons of DC electricity. The DC electricity flows to the inverter, where it’s transformed into AC electricity. This AC electricity is then either directed to your home’s electrical panel for immediate use, stored in batteries, or sent back to the power grid.
Installation Process
The installation of a solar PV system involves several steps, which should be carried out by professional installers:
- Site Assessment: Determining the best location for the solar panels.
- System Design: Tailoring the system size and components to fit the homeowner’s energy needs.
- Permitting: Obtaining necessary permits from local governments and utilities.
- Installation: Mounting the panels, installing the inverter, and setting up the electrical connections.
- Inspection and Commissioning: Having the system inspected by authorities and then activated.
Key Takeaways
- Solar PV systems are a cost-effective way to reduce electricity bills and carbon footprints.
- The efficiency of a solar PV system depends on the quality of the components and the installation.
- Government incentives and rebates can significantly reduce the upfront cost of a solar PV system.
FAQ: Solar Photovoltaic Systems
Q1: Can solar PV systems work during cloudy weather?
A1: Yes, solar PV systems can still generate electricity during cloudy weather, though their output will be reduced compared to sunny conditions. Modern solar panels are designed to capture different spectrums of light, meaning they can still function with diffused sunlight.
Q2: How long do solar PV systems typically last?
A2: Solar PV systems are built to be durable and long-lasting. Most solar panels come with a warranty of 25 years, but they can continue to operate effectively beyond that, often up to 30-35 years with proper maintenance.
Q3: Are solar PV systems maintenance-intensive?
A3: Solar PV systems require minimal maintenance. Regular cleaning of the panels to remove dust and debris and an annual check-up by a professional are generally sufficient to keep the system running smoothly.
Q4: Can I install a solar PV system myself?
A4: While it is technically possible to install a solar PV system yourself, it is highly recommended to have it installed by a certified professional. This ensures safety, compliance with local regulations, and optimal performance of the system.
Q5: Do solar PV systems increase home value?
A5: Yes, installing a solar PV system can increase your home’s value. Studies have shown that homes with solar energy systems sell for more than homes without them, as they offer the benefit of reduced utility bills.
Q6: What happens to excess electricity generated by my solar PV system?
A6: Excess electricity can either be stored in a battery system for later use or sent back to the grid if your system is grid-tied. Many utilities offer net metering, which credits you for the electricity you add to the grid.
Q7: Are there any government incentives for installing a solar PV system?
A7: Many governments offer incentives for solar PV system installation, such as tax credits, rebates, and feed-in tariffs. These incentives vary by location and can significantly offset the initial investment cost.
Q8: How do I choose the right size solar PV system for my home?
A8: The right size for your solar PV system depends on several factors, including your energy usage, the available space for panels, and your budget. A solar energy professional can perform a detailed assessment to recommend the most suitable system size for your needs.
Conclusion
Solar PV systems are no longer a novelty; they are a viable and increasingly popular choice for homeowners looking to reduce their energy costs and environmental impact. Understanding the basics of how these systems work and what components are necessary can empower you to make informed decisions about solar energy.
As the solar industry evolves, staying informed about the latest technologies and best practices is crucial. Remember, investing in a solar PV system is not just about adopting new technology—it’s about investing in a sustainable future.
About the Author: Who is Federico Calderon?
Federico Calderon is a seasoned professional with a rich tapestry of experience that spans over two decades across various high-stakes industries. With over five years dedicated to the solar sector, Federico has cultivated a deep understanding of renewable energy and its pivotal role in today’s world. His expertise is not just limited to solar; for over eighteen years, he has been a dynamic force in the mortgage and real estate realms, navigating the complexities of property and finance with finesse and a forward-thinking approach.
Licensed as a Broker in both Florida and Nevada, Federico brings a wealth of knowledge and a network of resources to his clients. His credentials are further bolstered by his federal-level accreditation as a Licensed Mortgage Banker, recognized by the Nationwide Multistate Licensing System (NMLS). This dual expertise in real estate and mortgage banking allows him to offer a comprehensive suite of services that are invaluable to homeowners and investors alike.
In addition to his brokerage and banking capabilities, Federico is also a certified Property Management Permit holder in the states of Nevada and Florida. This certification is a testament to his commitment to excellence and his ability to manage properties with the utmost professionalism and efficiency. Federico Calderon is not just a name in the industry; he is a trusted advisor, a strategic thinker, and a visionary leader who is dedicated to empowering homeowners and shaping the future of solar energy and real estate.
Additional Resources
For a more interactive learning experience, we invite you to watch our detailed YouTube video on “Solar Photovoltaic System Basics.” We’ve also provided a full video transcript below for your convenience, ensuring you have access to all the information in the format that suits you best.
hello everyone and welcome to today’s tpc webinar entitled fundamentals of
0:07solar photovoltaic systems my name is ryan smith i’m going to be your presenter today during today’s
0:13session um as we get started to really talk about this fundamental um concepts and some maintenance
0:19procedures with solar photovoltaic systems i wanted to let everyone know as you’re flowing in
0:24um a couple of the little housekeeping items before we get started first things first uh this webinar is
0:30being recorded and the video recording of this presentation will be made available
0:36on our tpc training website uh within about two business days from this event so be on the lookout for that secondly
0:44i’d like to also indicate that this session is live so that means you’re actually free to
0:50ask any questions you like throughout the session in the q a box if you look at the bottom of your screen you should see a q a button
0:57that you can type in your questions beware there’s a chat button too that we’re not going to be monitoring so
1:03you want to avoid using chat and instead use the official q a so we can monitor the different questions coming in
1:08and finally with that recording will be a pdf of these slides available uh for download at that time so um
1:15that’s kind of a little bit of of some of the housekeeping to get out of the way
1:21the last thing i want to check in with everyone here who’s flowing in is just to learn a little bit more about who’s
1:26here by doing a little introductory poll with everyone as we start to talk about some of the pv stuff we’re going to talk
1:32about today and some of the fundamentals i’m going to launch a poll for you all right now and so a window should be
1:40popping up on your screen with three questions the first question being
1:45how comfortable are you with explaining how solar panels work in terms of the function of how they
1:50produce electricity are you very comfortable explaining that somewhat comfortable kind of neither here nor there are you
1:56pretty uncomfortable you’re not really sure how to explain it or you just really don’t know how to explain it
2:02uh the second thing uh how often do you work on solar panels in your daily job
2:07is it often is it occasionally every now and then rarely or never right now and that’s okay if you never work on them now that’s the point of
2:14learning about some of the fundamentals to get started and the third question we have is which
2:20statement best describes your interest in the solar topic i am presently responsible for maintaining and operating solar panels
2:27i may be operating or maintaining solar panels in the near future or i don’t work on solar panels now but
2:33i want to learn more about them just a little bit more about who’s here and what you’re hoping to learn
2:40okay we got a good collection of answers coming in i’ll give you just a few more moments to make your selections
2:46yeah you can go ahead and click each answer you want to indicate and then hit submit at the bottom of the three
2:52question poll it should release your answers there
2:58okay good i think we’re getting a good evening out of the answers coming in i’m going to go ahead
3:03and end the poll and then share the results with everyone
3:08here so you should see a different window popping up with all the results from today’s poll as you can imagine the
3:17level of comfortableness i guess the level of comfort um on explaining how a solar panel works
3:22it’s across the board so really it’s an even split from people who are somewhat comfortable to people who are somewhat uncomfortable
3:28explaining how solar panels work in the whole photovoltaic process so we’re going to explain that and break that down a
3:34little bit in today’s webinar the second question is how often do you
3:39work on solar panels so most of you do not presently work on solar panels at all and i which kind of leads us to the
3:46prevailing answer from number three which is most of you are coming into this session having not worked on solar panels and
3:53not working on solar panels presently but you do want to learn more about them and so that’s really going to be the motivation for this session it’s going
3:59to be the basics it’s going to be kind of starting off the uh the breaking down of some of the terms
4:05of solar panels how they work how to maybe understand some of the things you might start seeing on spec sheets for
4:10solar panels and what to look out for during the initial installation and
4:16maintenance of these solar panels so i’m going to go ahead and stop sharing the results i appreciate your input thanks so much
4:22all right so that window should have disappeared from it if it didn’t go ahead and just hit the x button and we’ll go ahead and get started
4:30so the really the breakdown of today’s session is going to be all about first and
4:35foremost explaining the fact thatElectrical Basics
4:41these devices are primarily electrical devices so solar power can’t really be fully
4:47understood unless we understood electricity itself electricity is a big part of what tpc does in the training business you
4:53know learning about electricity and how to do electrical troubleshooting and all those types of skills apply when you’re trying to understand how solar
5:00panels work as well so that means we really have to break down the three fundamental basics of
5:05electricity and how it works to really understand how a solar panel works that’s electrical current electrical
5:11voltage and resistance and knowing how those three work together is important
5:17and how they’re related is really important in understanding a solar panel so this is where we’re going to start is kind of on the electrical thing real
5:23quick and understanding some of the terms there then we’re going to jump into for a few minutes of the solar
5:29photovoltaic process so the process of converting the sun’s light into energy and and how that works knowing a little bit
5:36more about the materials used in solar panels and how they’re put together and then finally we’re going to end
5:42today’s session on just some of the best practices we have documented on how to maintain and take care of
5:48solar panels as as someone who might be responsible for that now or in the future
5:55first and foremost these three here i could tell you even if someone’s been
6:01working as an electrician for 30 years right still need to refresh
6:07yourself on knowing the difference between electrical current electrical voltage and electrical resistance and kind of
6:13how they all play together it can get pretty easy to mix up current and voltage they might be kind of intermixed in
6:19terms of terminology or you know which one causes which does current cause voltage or does voltage
6:25cause current that kind of stuff it’s really important as we start understanding iv curves which we’re
6:30going to talk about today for for a solar photovoltaic panels or the short circuit current or the open
6:37circuit voltage all the stuff that is going to be on the spec sheet for panels we have to know
6:42first and foremost let’s talk about current so current really is the amount of electrons flowing
6:47through the wire and that’s able to be produced think of it as a flow of water
6:52through a pipe is similar to a flow of electrons negatively little charged electrons through the wire
6:59and again we can break this down in more detail if you take a basics of electricity course but i’ll just kind of keep it brief for now
7:04we got all the electrons flowing through the wire what’s behind them pushing that’s the voltage so basically
7:11if you think about um a water hose analogy right the water flowing through a hose if you turn that
7:17hose on is the current and then how open you made that spigot or that that
7:23faucet at the house and how open that is is the voltage so if it’s fully open
7:29that’s a high voltage which will cause more current or water to flow and then the size of that nozzle at the end
7:35where it sprays out into wherever it’s spraying into that’s the resistance so if there’s more resistance that means less current will
7:42flow in this system and that resistance can be found in whatever devices are usually
7:47hooked up to that that um device providing the voltage so for instance you know loads we call them
7:54applica appliances light bulbs motors and that kind of thing
8:00so which part of the equation are we really going to be talking most about and where does a solar panel come into play
8:07well the solar panel is if you see my little red laser pointer here a solar panel really is the thing
8:14in the electrical circuit that provides a voltage for that electrical circuit and it’s actually an alternative way
8:20to provide a voltage than what we normally do in this day and age we normally get our voltage
8:25our push for our electrons to flow through our homes and our businesses through our electrical grid which is
8:32connected to all of our you know hundreds of miles of utility wires and power plants throughout this country
8:38this time we’re able to produce a voltage directly from the sun’s light whether it’s on our own roof or a nearby
8:44uh a location that’s producing electricity from the sun instead of from our utility
8:50grid and that’s really what solar power is all about is creating this push on the electrons to move and to power our tvs and our
8:58lights and all that kind of stuff in another kind of way so thinking of the push the the more
9:04push the more voltage the more current to answer that question i posed to you
9:09just a moment ago can you have current without voltage well the answer is no you cannot have
9:16any current without some sort of push to make that electron current flow now let me put it the other way can you
9:22have a voltage without current and the answer is absolutely yes
9:27so you can have a voltage you can have that potential we call it that’s another word to describe voltage
9:32you can have that push or that potential happening but but without an actual completed path to make that
9:38electron flow so that’s kind of the difference you can have a voltage without a current a kind of waiting push ready for current
9:44to flow as soon as you make that path but you cannot have a current without a voltage
9:52so really the way they all play together is that one volt of electromotive force or what we callOhm’s Law
9:58that’s what voltage used to be called in days past we kind of change that term to be volts so one
10:04volt of voltage or electromotive force will force one amp the way we measure current of
10:10current to flow through a wire in this case to one ohm so the way we measure resistance or how much
10:17the appliance or device is holding back or even the wires themselves everything has resistance is holding
10:22back that current the more resistance that builds up around the solar panels and in the
10:27system the less current will be able to flow from those solar panels and the dimmer
10:33your lights are going to be connected to those solar panels this is how they all play together in
10:39terms of math if any of you here like math this is kind of how it all comes together so
10:46e is that electromotive force or voltage we call it i is it’s interesting i was always
10:52curious about why we use the letter i for current even the letter i isn’t in the word current well the uh the letter
10:58i comes from initially from the french word of an intensity so current was first kind of observed as
11:04an intensity of current the more the more current flowing the more intense that feeling was if you touched
11:10that wire right and so that kind of eye stuck around but it turned into the word current over the
11:15years since you know the 1800s and then r is resistance which makes sense to us so
11:21this pie chart really indicates that if if you know the voltage of your solar panels and you know the resistance you’re going
11:27to be hooking up the device to if you know any two of these ingredients in your electrical
11:32system you can find out the third ingredient by doing a little bit of math so the way
11:39this works let’s say you you don’t know the voltage you don’t know what the voltage is but you know
11:44what the current that’s flowing and you and you’ve measured the current the amps that are flowing and you measure the resistance you just cover up
11:50the part you don’t know so let’s say you covered up this this letter e with your hand you see an i and r left over next to
11:56each other so that means you take the i times the r so you take the number of amps times the number of ohms of
12:01resistance and that gives you the number of
12:06the number of volts that are are in action or required to make that many
12:11amps go through that many ohms uh in a lot of cases we’ll know the voltage of our panel because it’s on the
12:17nameplate and we’ll we will know the resistance because that’s on the nameplate of the device let’s say but we’re not sure how much current is
12:24going to flow and let’s say how big our wires need to be to hold that amount of current so a common application is we cover up
12:29the i because we’re not sure how many amps are going to flow and then we find out that e over r because e is on top of the r
12:35this time so if we cover up the i it’ll be e over r or voltage divided by current
12:41to get the number of amps so let’s say we have you know 10 10 volts or let’s say
12:4724 volts and 2 ohms that’s 24 divided by two and that gives
12:53us 12 amps that will flow for instance
12:58so they all play together and then one interesting way to bringPower
13:03them together in terms of how to understand solar panel name plates and ratings is this
13:09power so we sometimes mix up the term power in other words what our meters are
13:16reading in the backyard of our homes and our businesses is voltage right or so it’s measuring some
13:22sort of voltage or current flowing well it’s none of the above it’s actually both
13:27um together multiplied so if you take the voltage at any given moment coming into your facility and you
13:33multiply it by the current flowing in that moment of time
13:38that gives you a measurement of volts times amps then you put that together to get watts
13:44watts and so watts is the measure of power and that’s really what you’re going to see
13:49in a solar panel nameplate is how many watts does that solar panel give you so that means how many amps times volts
13:55together in combination can that solar panel give you
14:01let’s say the solar panel is out for 24 hours so it’s going to give you a certain amount of volts
14:08coming from that solar panel we’re going to talk about the magic of how that happens and then how many amps it delivers and
14:13the magic of how that happens you multiply that together over 24 hours and that gives you watts times hours
14:20and that gives you what we call watt hours or multiply that by a thousand to make it easier to read it’s kilowatt
14:26hours or a thousand watt hours delivered in that day let’s say or however long you want to say over the course of a
14:31month usually is how our utilities measure kilowatt hours used so you take the volts and amps
14:38being used multiply it by the number of hours it was being generated and you get kilowatt hours and that’s
14:43normally how our electrical utilities charge us for our electricity or
14:49if you’re going to be one of the lucky folks who have their solar panels hooked up as a net metering solution
14:56that you can actually charge back the utility a certain dollars per kilowatt hour uh based on how these are producing
15:03their volts and amps over the number of hours so obviously at in the middle of the night midnight a solar panel is going to
15:10produce zero kilowatt hours um but as the sun comes up and things start increasing
15:17um in terms of light then they’re going to produce more kilowatt hours but you average it out over the course of the day to get a kind
15:23of average kilowatt hours or total kilowatt hours for the day or for the month
15:29so watts is important watts are not volts and watts are not amps they’re a mixture of both that’s that’s another
15:34important one so once we kind of get that down take
15:40some practice to really start talking the talk of watts kilowatts voltage amps
15:47this is where we can start really talking about the solar panel itself i know you haven’t even seen a picture of a solar panel yet on the screen but
15:52it’s coming now so to understand how photovoltaic works if you think
15:58about it now photo that’s light right so photons and that kind of thing
16:03volts is creating voltage right so voltage so creating light or secreting volts from light
16:11in other words creating volts from the sun’s light because that’s the most intense energy free of freely available light we have
16:18so is there a way to create voltage and electricity immediately from light and the answer is yes we discovered it
16:24over the last several decades so let’s talk about that the first and most important building block of
16:31what it takes to convert light into voltage is what we call the solar cell and thisA Single Solar Cell
16:38is what one looks like this is not a solar panel that sometimes can get confused a solar cell is not a
16:43solar panel this little thing is just a frac you know one inch wide by one inch long so it’s a tiny little thing
16:50they come in different shapes and sizes but in this case this can fit in the palm of your hand
16:55this is a single cell and what this does is magically the sun will shine on this
17:03cell and immediately be turned into electricity and that’s one thing that’s
17:08uh pretty amazing about solar power is that there is no moving parts in a solar
17:15panel or a photovoltaic system they literally just sit there never moving never uh you know having
17:22any vibration or strain or you know bearings and
17:27and misalignments and pumps and motors and that kind of thing generators to do what they do they they
17:33just do what they do naturally just from the sake of what they are and so we got to talk about that but
17:38essentially this this is able to immediately take the sun’s energy turn it into
17:43uh electrical energy instantly and so a cell about this big can do that
17:50and produce about 0.5 volts of of push or potential we call it for an
17:55electron to flow that’s remember that’s not amps that’s not you know powering my light bulb yet we have to know how many amps it’s going to
18:01pull through and how many watts it can do so we get there but for instance does anything in my house
18:07let’s say your own home what voltage does your cell phone need to plug into a wall
18:13right what voltage does your television or your refrigerator need to plug into the wall right well it’s not half a volt that’s
18:19for sure they need a little bit more push on their electrons to get them to work because they have high resistance
18:24so and ends up being you know in today’s modern day we in the united states power our devices
18:31on 120 volts so we need 120 volts so this single solar cell is not going to work for us
18:37we need more so what do we do well thankfully through the magic of uh
18:43electrical circuits we can string together multiple of these cells
18:49in a row and then each time we get a new one in the row we add that 0.5 volts again so we get
18:55point five volts and then one volt and then one and a half two two and a half three three and a half four until we get a whole solar panel
19:02that can be you know 30 volts 35 volts or even more depending on how many cells you can fit
19:07into a single what we call solar module and that’s really how we can get a system up to 120
19:14volts but before we start building blocks with these solar cells i want to show you one
19:19more thing about this solar cell let’s talk about energy in versus energy out this is the most importantEnergy In vs. Energy Out
19:26thing to consider um and this is where you can start really impressing your co-workers and colleagues about your knowledge of solar
19:32power is this idea of efficiency of a solar cell so we all know that the sun’s light is
19:40shining on a solar panel and then that solar panel through what
19:45it does or that solar cell right it takes the sunlight’s energy in watts
19:51it seems strange to con consider the sun’s energy to be watts we usually think of a light bulb
19:56or something in watts but yeah the sunset energy can be measured in watts and then on the output of this solar
20:04cell it takes a smaller proportion you see that smaller sized arrow here is the electrical energy that it’s
20:09giving us in watts so the number of watts coming in from the sun
20:15turns into a smaller amount of watts being produced by the solar panel
20:20so we didn’t we weren’t able to harness all of the watts from the sun in these solar panels unfortunately but what we normally find
20:28out in a given case let’s say we want to learn how effective or how
20:33efficient is this solar cell in providing us the energy from the sun’s light
20:39well uh the the efficiency it number is what we talk about so we take whatever is coming out
20:44and we divide it by what it came in to provide us with that amount of power and that gives us an efficiency
20:49for instance if we got 100 watts of the sunlight’s power and the solar cell produced 15 watts of
20:56power on its output we can do the math uh 15 divided by 100 and that’s 15
21:04so that that’s 15 over 100.15 or 15 that’s the efficiency of this solar cell
21:10for every 100 watts it’s given it only produces 15 watts right and that’s typical so what we find is a
21:17typical this is another really good thing to just impress your coworkers with hopefully is a typical solar cell efficiency right
21:23now of the typical material for solar cells which we’re going to get into is about 15 to 20
21:28percent efficient when it’s brought to market granted when these are sitting in a
21:34laboratory you know in the national renewable energy laboratory for instance in a very ideal condition these can get up to you know
21:4030 40 efficient in the lab but once they’re out in the real world with clouds coming over and
21:45day and night and leaves and dirt and wind and all this stuff the the typical efficiency of a solar
21:51cell is at 15 to 20 percent so that doesn’t seem great right 15
21:56efficient if if anyone said yeah i’m 15 efficient at getting my job done that’s not very effective but you got to
22:02remember that the sun’s light is freely available it’s going to shine on that rooftop or
22:07shine on the ground or wherever you install these freely right and it’s not really going to cost
22:13you money and so getting 15 of something that’s free well that’s free that’s freely available energy at that
22:18point as long as you can incur the cost of installation
22:24so that’s something to consider here um another fun fact is that the word we use to indicate the
22:30sunlight’s energy in watts available let’s say in a certain location is something we call
22:35insolation so not insulation like we see in wires or in our wall but in soleation with an o the solar
22:43radiation of a certain area so you get more insulation or watts per meter squared in some
22:48a place like you know southern california or texas or florida because you’re
22:54closer to the equator then you do somewhere further north like seattle or um or michigan because the sun is not as
23:00direct up there for instance so that’s kind of an example of insulation and it’s good to know about that okay so
23:06the sunlight is coming into the cell the sunlight is coming out of this cell taking a look at the cell it’s still itElectron Flow
23:13still might be a mystery right to anyone listening about
23:18okay it’s creating energy but how right it’s there’s got to be something moving right there’s got to be something working
23:24and it’s pretty amazing it all happens at the sub-atomic level so to to help uh just
23:32refresh some of our memory from high school physics class bring yourself back to high school or junior high or maybe even elementary
23:39school sometimes i didn’t learn about this in elementary school but some people i i know are learning about technology school about
23:45electrons protons neutrons and electrons that’s what this all comes down to with solar photovoltaic
23:52you might remember that electrons the the parts of an atom that flow through a circuit are negatively charged
24:01so what manufacturers of solar panels do is they take a semi-conductive material
24:09so not a conductor you may have heard of conductors if you’re any electrical folks on the call know
24:14what a conductor is because you see that word all the time in the national electrical code conductor something that conducts electricity readily that’s you know
24:22metal steel um copper aluminum that kind of thing versus the opposite of conductor which
24:29is an insulator that’s you know rubber wood um glass that kind of stuff
24:35what we need to make a solar panel work is something in between something that’s not quite a conductor like metal but
24:41it’s not not quite an insulator like rubber it needs to be somewhere in between and a really good candidate for
24:47something that’s kind of conductive in only certain situations is silicon
24:52so this is something naturally occurring in the earth that is that can be found in large quantities
24:57that is a semiconductor there’s other materials out there like gallium arsenide and other things that we’re experimenting with
25:03but silicon the element silicon is the perfect semiconductor for this and so what we do is by itself silicon
25:10is not super useful as in a solar panel until you start doping it we call we call doping
25:16the silicon and so what you’re going to see is that the top layer the the layer that’s facing the sun is
25:22doped with an n-type semiconductor so that silicon is turned into a negative charge or n
25:27type versus the bottom layer that’s kind of in the shade underneath is a positive type semiconductor p
25:34p-type usually we use the element boron to dope this semiconductor here
25:39and we use the element phosphorus to dope with the silicon kind of add in to the silicon as an additive um on the
25:47bottom end so what that ends up doing is it produces an extra electron
25:52in the cell structure the crystal structure of the um solar panel on the top end so there’s
25:59electr an actual an extra electron floating around in this layer of the material right here
26:07well electrons are negatively charged and if you’ve ever held two magnets together how do they attract and
26:12how do they repel well you we know that a negative and negative repel so anything negatively charged
26:18repels a negatively charged electron floating around in here and anything positively charged attracts
26:23that electron however right so you see okay an electron is negatively charged where
26:29does it want to go it wants to go to this positive side but thanks to this separator here this membrane
26:34the electrons can’t flow just directly down so what’s the only other way is to travel on this line we provided to
26:41it and it’s going to leave the solar panel feel the pull to that negative that positive side but
26:47instead it’s going to go all the way through our home or our business it’s going to power the devices and then
26:53come back out all used up and flow here so this is actually this arrow is showing electric
26:59current flowing that way but that’s not actually not right it’s going the other way so the holes of the electrical current are
27:05going that way which they some people call the holes of the electrical current anyway the electrons go this way this way over
27:11over and back down again and then they fill in the extra spot available for those electrons down here
27:17and then through this membrane they can replenish and start the process over again so it’s really it’s really an
27:24amazing process that all is kick-started by the sun’s light so nothing’s going to happen
27:29with that until that electron is allowed to jump suddenly from one area of this material
27:34to another thanks to the ultraviolet and infrared and all that fun light the energy in the sun’s light
27:41makes this process happen and it’s amazing how it just magically happens with enough solar power
27:47with the sun shining and so it just happens time and again naturally you don’t see
27:52anything rotating and moving in here and that’s what really makes solar panels pretty good in terms of
27:58maintenance and we’re going to talk about the maintenance so we’ve been talking about the cell right that single one little
28:04inch tab that you see on a solar panel obviously there’s way more to it than that so the way we build them togetherPhotovoltaic Building Blocks
28:10typically is we see a cell we bring a cell for a photovoltaic panel
28:16and we put them all together in a string like we mentioned to kick up that voltage a little bit and
28:22that turns us into a single module if you want to talk the talk
28:27again the term module is really what the industry uses to indicate the solar panel so that single that
28:34single off the shelf device with a bunch of cells put together in series is called a module
28:40or another word for it is a solar panel right so put all the cells together into a module you put a bunch of modules
28:46together and to kick up that voltage even further from panel to panel to panel
28:52to kick up the current or to kick up the voltage whatever you need and that gives you an array so basically
28:57a bunch of panels together give you a photovoltaic array
29:03and then you put a bunch of arrays together to really start providing some let’s say a full
29:09house worth of electricity or a full businesses worth of electrical needs for whatever whatever
29:16it is that gives you a system but the system isn’t just all the panels together the system also includes
29:22all the other stuff which we’re gonna just touch upon at the end of this but that goes beyond the basics so we don’t really have time for it but
29:28includes energy storage like batteries voltage regulation and inverters and combiners and a bunch of other
29:34fun thingsHow do Solar Panels Work?
29:39so here’s a panel right um provided off the shelf from the manufacturer you can see
29:44if you kind of count you can see one two three four five six cells in this row six times one two
29:50three four five six seven eight 9 10 11 12 6 times 12.
29:55so that really gives you about 72 different cells put together at what is it half a volt for cell let’s
30:01say that’s that’s going to be about 37 volts for this single panel right and you can
30:08look at its spec sheet to verify that and so this panel in and of itself can’t produce enough voltage but then
30:15the more you put together more panels you put together the higher the voltage can be
30:21so this semiconductor material again it’s the silicon and there’s two different types of
30:26silicon out there in the market right now and i think another really great way to talk the talk and to really start
30:32understanding some of these photovoltaic systems is to talk monocrystalline
30:37silicon or polycrystalline silicon are the two kind of most widely available silicon alternatives but
30:43again there’s other stuff out there that people are trying out uh like amorphous silicon we’ll talk about briefly gallium
30:49arsenide is another semiconductor compound that’s used cadmium telluride
30:57is another one that’s come up over the years so once you get that right device that does something with its electrons once
31:03the sun’s light hits it then we’re then we’re starting to have something we can work withPolycrystalline vs. Monocrsystalline
31:09but talking about silicon which is still one of the more common ones is the polycrystalline versus the monty
31:14crystalline you can kind of see visually the difference in how they look so polycrystalline
31:21here it’s it’s poly it’s many different types of crystals so it’s kind of the natural way
31:26in which um in which silicon comes together and it’s kind of jagged
31:31different crystal structure because of that it’s uh cheaper to make something like polycrystalline
31:38monocrystalline is is manufacturing the silicon to be all uniform in in
31:44texture and in crystal structure in this system so this is the one we saw earlier
31:51right and this is a polycrystalline what are the pros and cons here well you’ll notice when you start looking at
31:56spec sheets and just start exploring different solar panels and things like that polycrystalline has less efficiency
32:05but it’s cheaper to produce so that’s kind of a trade-off if if you
32:11have let’s say space to spare on your rooftop or your yard or your
32:16your location if you have no space constraints and you have as much space as you need you can probably
32:21be more cost effective with getting polycrystalline panels but if you have a limited amount of space let’s say you know a limited 100 square
32:29feet on top of a roof or something like that monocrystalline is more efficient but it’s also more
32:35expensive because it takes longer and more intensive to produce than
32:40polycrystalline so more expensive but they’re more efficient so if you’re if you’re strapped for um for space the
32:48monocrystalline is the way to go and then there’s the other consideration
32:53of amorphous so amorphous silicon is really kind of a free-flowing crystal structure without
32:59actually much crystal structure to begin with at all and because of that whoops it it is more flexibleAmorphous Silicon – Flexible Thin Film
33:06so this is an example of an amorphous silicon panel it can be bent it can be kind of rolled
33:12up it can be put on a curve curvaceous surface like a like a windowsill or a sloped roof or
33:19as used as a solar shingle a lot of companies are offering amorphous silicon
33:25in the sense of solar shingles that can be just laid in any sort of
33:30application because it’s amorphous and kind of random it’s less efficient than the other two that are crystalline
33:37but you can see how you can see how maybe it can be used in more areas because it’s flexible it’s easy to roll
33:42out it’s easy to deploy you know on the top of your car some solar powered cars that are out
33:47there solar powered plane that we talk about in our two-day photovoltaic class
33:53um a solar powered you know a small uh what do you call it uh a
33:59dune buggy or you know a golf cart is solar-powered golf carts with amorphous on top that can be you know you don’t need a whole panel on
34:06the car you can just line the top of the car with these things so these are kind of the real value here
34:11even though they’re not as efficient they are more flexible okay so there’s different kind of
34:18products out there on the market and what you find in each of these solar cellsIV Curve of a Solar Cell
34:24these solar options is what we call the iv curve this is this is getting to the this is about the level of complexity
34:30i’ll get to when it comes to house how photovoltaic panels work
34:36and then you know i’ll just talk a little bit more after this about the whole maintenance uh and some of the best practices of
34:42care for these panels and then i’ll see which questions we can take at the end okay so the iv
34:48curve iv is not you know intravenous it’s not something you put in your arm but it is iv if you recall back to
34:56earlier it’s the current voltage so current and voltage curve
35:01this thing can’t have its cake and eat it too so to speak you can’t have maximum current and maximum voltage at
35:07all times you have to trade off current with voltage so if you want this panel to push harder
35:14and provide more voltage then you should expect less current and if you want more current you’re
35:22gonna have to expect a trade-off in the voltage and so that’s really um what this curve is
35:28telling us that let’s say we want
35:34just uh so we start here right on this side of the the curve where there’s zero zero amps
35:41flowing through the wire when does a does a solar panel have zero amps flowing
35:47even though the sun’s shining it’s when one side to the other of the panel is not connected to anything right
35:53if it’s not connected anything the solar panel is not going to give you any current so that’s what we call an open circuit
36:00where you know the positive and the negative lead of the solar panel are just sitting there without anything connected to it but if
36:06you put an electrical meter on both of those positive and negative leads those those connectors on the solar panel it’ll give
36:12you a reading and that reading is the open circuit voltage or voc
36:17open circuit voltage that’s if this panel doesn’t have any load attached to it it’ll give you this voltage that’s the
36:23best case that’s the highest voltage you can possibly ask for obviously that doesn’t mean too much to
36:29us if we’re trying to hook these up somewhere right and so
36:35the voltage starts dropping off a little bit as we try to get some current flowing
36:41and if we take it all the way to the other side we’ll start being able to see more and more current flow until we kind
36:46of even out so um we kind of even out and max
36:52max out at this current that that this solar panel can produce or the solar cell can produce
36:57up to the point where we have no voltage being produced and all the
37:04current being produced how does that work well i want to ask anyone here how do i
37:10get the most current to flow as possible on a device well if you’ve ever
37:15pranked someone or ever had the misfortune of experiencing this you put the hot and the neutral together or the plus and the minus wire directly
37:22together and you cause what we call a boom right or a short circuit um you don’t you want to avoid that
37:29short circuits are you try to avoid that but there is a a good metric for for solar panels is their short
37:36circuit current so how much current will they pump out at yeah if you for any reason
37:41lost your resistance and went completely wire to wire from positive to negative um that’s the short circuit current so
37:47that’s the maximum current and the maximum voltage but then somewhere in between is a sweet spot
37:53and that’s right here usually along the the iv curve where the the current has dropped off just a little bit from its maximum and
37:59the voltage is dropped off just a little bit from its maximum where you put them together voltage and amps
38:04together it gives you the most watts possible right because if the panel operated here you
38:10wouldn’t get much watts with the volts and amps together over here you wouldn’t but right here is the sweet spot so this is
38:16where you want to kind of operate your cell and if you find yourself let’s say i’m starting to measure more volts and this is where the care
38:22and maintenance comes in if you’re doing your measurements once a once a year or every six months on these and you start seeing the voltage go over
38:29here or over to there we know that we might want to start doing some more inspection on these panels
38:36okay so that’s kind of on the cell level we all know that solar panels don’t
38:42exist all by themselves they need a bunch of extra equipment to be able to work in their system as
38:48well and so at the end of the day those electrons start flowing down that wirePhotovoltaic Facts
38:54on the top layer that we saw earlier and they’re producing what we call direct current or dc power
39:00that direct current it means the electrons are flowing in one direction they’re not flowing back and they’re not alternating they’re just going straight into the
39:07home or straight into the business unfortunately your
39:14businesses are homes they don’t operate on dc power in most cases they operate on ac
39:19or alternating current where the the current’s fluctuating 60 times every second
39:24so to get that power from a pv panel photovoltaic panel into a language that our devices in our
39:31homes and businesses can can use we need something we call an inverter
39:36and so an inverter is a good part of a whole system where the dc power produced by the panels
39:43needs to be turned into alternating power through an electronic device called an inverter these are really uh again for a
39:50whole new week-long class just on how inverters work there’s a lot of complication in there with all the electronics
39:56but at the end of the day they turn dc power into ac
40:02and so one way we could wire in a solar panel into a system is that get the panels directly into dc
40:08loads there are such things like light bulbs like leds you may have been hearing about these leds
40:14dc powered motors or batteries based systems that power off of dc only they’re rare
40:20and they need special connections and things and they normally powered off of batteries like our phone or
40:26our laptop when it’s not plugged into the wall that kind of thing or if we want it to speak our normal
40:32language of our homes or we can plug stuff into a regular outlet we need that inverter so the panel
40:37produces dc goes into the inverter the inverter does its magic and now we have ac alternating current over to ac loads
40:44like our motors our refrigerator our tv and so on and so forth
40:51all right so just for the next few minutes i want to talk a little bit about care of our solar panels right and kind of
40:59what are some best practices we can’t get into them all but what i can share with you is that the national renewable energy lab
41:05we call them nrel nrel they produced an exhaustive report that you could all can
41:10read immediately after this webinar if you like and just really dive into those 100 pages of best practices for
41:17operation and maintenance of photovoltaic and energy storage systems and this is the third edition that just came out in 2019
41:24and it’s really an exhaustive look at some considerations you should have for care of your solar panels
41:30and so i’m going to highlight some of the things that that we found most interesting in this report that that are really good to highlight
41:37on this webinar and then we’ll take time for questions definitely find this report for yourself it’s freely
41:43available through the national renewable energy labPV Module PM Activities
41:49first and foremost what are some pm or preventative maintenance activities we can we can run on our solar panels
41:55themselves that’s what we’re going to focus on we’re not going to get into all the peripheral equipment like inverters necessarily we don’t really have time
42:00but as you can imagine these solar panels even though they’re not moving so you’re not dealing with you know bearings
42:07breaking down or vibration and that kind of stuff what you do have in its place is the
42:12fact that these are out in the elements right so they’re out in the dust and the snow and the rain and the
42:18bird poop and you know all the other stuff the ice that can happen um and all that kind of
42:23stuff so cleaning uh needs to be really part of the plant
42:28on how you’re going to clean the photovoltaic panels at the end of the day you want to try to
42:36avoid just doing it yourself just kind of you know haphazardly wiping it down with you know steel wool
42:45or just whatever brush you have laying around or whatever a cleaning solution you have laying around because
42:51these these laminations on top of the solar panels are very
42:57specific you know chemical compound that can be compromised if you use harsher types of solvents or more
43:03abrasive materials imagine scratching the glass for instance on
43:09the top of the solar panel you’re immediately just obstructing the ability for light to get
43:15through to the cell and that means the efficiency of this panel starts dropping and you get less
43:21money for your dollar so it’s really good there’s a lot of official and regional module pv module cleaners
43:28available for cleaning services you know that they can charge just a one-time fee and they’ll do a full cleaning with the
43:35with the correctly rated equipment for your system but if you’re going to do it yourself again not recommended
43:41but use soft bristled brushes or try to avoid using brushes altogether
43:47okay snow removal is another thing for people like me we’re coming at you in chicago illinois uh snow removal is a
43:54reality for anyone above that level of latitude where we get snow
44:00um a good kind of thing that designers of solar panels do is they tend to
44:05angle up the solar panels in the winter time the fall and the winter so you know a six-month rotation of
44:11going up onto that rooftop let’s say and angling up the solar panels a little bit
44:17the main reason we do that is because now the sun is at a angle so that the sun is hitting these
44:22more dead on if these are south facing so if the sun is more directly hitting these solar panels
44:28then it’ll get more output because it’s facing the sun more directly
44:33and then another benefit that this higher angle provides i think you see where i’m going here is that the snow
44:39will just more naturally fall off the solar panel as well and help you avoid some of that snow removal
44:44so it kind of serves a dual purpose for um for maintenance of the solar panels but at the end of the day even
44:51snow um and this you’ll see this in the nrel report as well um the snow
44:58is uh sometimes is still a consideration because the rooftop might only be able to handle
45:05so many pounds and i one of you asked a great question um before the session began about you
45:10know what roofing materials am i allowed to use for my solar installation and the answer is well you’re allowed to use
45:16pretty much any roof there is you just have to have different considerations there is but certain roofs have different um total load requirements or total
45:24pounds that can be loaded on there and the nrel report i’ll refer that multiple times
45:30is really exhaustive about analyzing the different types of roofing materials and how much it might cost to replace
45:36and repair them in considerations so yeah snow removal still might need to happen even though these naturally slide
45:42off at higher than 30 degree angles you still might have to go up there and clear out snow just to make sure your roof doesn’t cave in so be
45:47aware that dust so dust agricultural industrial pollen cleaning
45:53same thing with the cleaning considerations and then finally any good pm and really i will take this to a pdm
46:00a predictive maintenance perspective on these panels um
46:06is if if you can use ir scanning an infrared thermography company a specialist to come in
46:11and do a correctly calibrated infrared thermography scan of these panels you
46:16can really see where the problem spots are that maybe your naked eye cannot it’ll show for in the case of this
46:22example right here which part of that solar panel which cells are giving us issues if cells are heating up like this you
46:28can see the red these cells are much hotter than the ones around them that might mean they’re
46:33they’re starting to fail and there’s something physically going wrong with them versus what’s going on around them and
46:39each time one of these gets hotter than the rest that extra heat if you think about one thing i forgot to
46:44mention is if you have that 100 watts of solar power coming in and only 15 watts coming
46:50out where do the other 85 watts go they can’t just disappear they all come out of the solar panel as heat right so heat that is just
46:57rising up off the solar panels they get really hot if anyone has ever touched a solar panel in operation it’s
47:03really hot so if there’s extra heat being get given off of these panels beyond the
47:08manufacturer’s specifications that means the solar the heat is rising and that means in in turn that
47:16we’re getting less efficiency for our dollar so that’s just some initial considerations there
47:23other ones checking the torque all manufacturers and all electrical equipment have a manufacturer’s spec for torque so
47:29how tight these screws and connections need to be in terms of foot pounds or or newton
47:35meters of force and using a correctly calibrated torquing instrument
47:40uh to tighten those down as of the 2017 national electrical code
47:45is part of is a real uh big motivator for starting to officially
47:51require all these torquings to be done at least every five years or if not sooner depending on the manufacturer’s
47:56recommendations especially if you’re outdoors in a in a volatile environment with wind and snow and rain
48:01that can happen all this kind of stuff has to do with being out in the in the environment right checking your
48:07torques checking for corrosion and yellowing yellowing is another really interesting thing
48:13um where the coating that’s on top of these panels can actually come directly from the manufacturer
48:20causing a unwanted chemical reaction with the with the cells and i think i have a picture of them coming up of what these
48:26yellow cells and they can straight off the shelf can actually just have have a manufacturer’s defect that
48:31was in action during shipping that can cause problems so just the visual inspection making sure the yellowing doesn’t happen
48:37in galvanization there’s no rusting happening so a lot of visual inspection is is involved in place of mechanical
48:44replacements and inspections here’s a cleaning so cleaning panels you see this very soft bristled brushCleaning Panels
48:50using the right amount of um solvents here in this case and again we always recommend using
48:56panels an interesting tidbit here that we’re finding is that proper cleaning does make these panels
49:02up to 20 more efficient right so that’s not 20 efficient that’s that’s high but 20 more
49:09so let’s say you’re you’re only pulling 12 efficiency right that’s less than the 15 we want
49:14but then you start cleaning these things you clean all the dirt and the bird poop off of them and you get somewhere from 12 um
49:21watts you’re producing to 15 right and then you get back up into the specs
49:27so this is what they looked like before and over here you can see what difference that can make in terms of letting light throughBefore Installation: Check for Defects
49:33here’s that yellowing i wanted to tell you about so you can kind of it’s subtle but you can see it if the panels
49:38are starting to look yellow you can you can see that there’s an issue there as well
49:43another thing that can happen straight from the manufacturer especially if these are being shipped to you the frame can get
49:49bent and be defective in terms of not sealed properly these cells are supposed to be sealed
49:55off from the elements in the environment but if the glass ever gets shattered or broken in manufacturing or shipping
50:02you immediately start seeing issues with the panel and then when that rain water gets in with electrical electrons flowing a lot
50:09of short circuits and issues happen inside the panel from there as wellFailure Rates According to Customer Complaints
50:15interesting uh pie chart from the iea is kind of the breakdown of the
50:21different uh main causes the failure rates according to customer complaints for solar panels
50:28and that is um so i’ll just talk for a little bit um just maybe two or three more minutes
50:35and i’ll try to take as many of your questions as possible i want to honor your one minute or sorry your one hour time commitment
50:41here so i want to make sure to honor that for you but 20 is that optical failure so the biggest one
50:47is that if these things are fairly failing because they’re not able to get
50:52um they’re not able to get the process of photovoltaics happening and the light through to them power loss so they’re just not producing
50:58as much as they used to and that’s because connections are coming loose over time or whatever
51:04and then all the kind of uh connected stuff right it has to do with it other
51:09than that uh let’s see kind of all the same stuff other than the panels i just would sayAC Wiring PM Activities
51:15that this nrel report check it out because it starts getting into things like ac wiring
51:21so not just the panels themselves but you have all the wiring and all the conduit that goes all around to the inverter and the disconnect
51:29switches and all the other stuff that you have to make sure you’re torquing as well checking their
51:34position inspecting them for not only corrosion but yeah water and insects
51:40man oh man snakes rats mouse birds making nests and that’s a big one
51:45birds making nests inside these panels like this so these birds said oh thesePV Array PM Activities, cont’d
51:51these are nice and warm spots to sit and this is straight out of that report and so thank you for letting me use this
51:56um bird poop right it’s just a reality of having stuff on a on a rooftop they
52:04affect the solar panels performance significantly so that’s something you want to be aware of as well
52:10nesting can happen inside these connector boxes and combiner boxes as well so it’s always good to run that visual
52:16inspection going back to this some of the electrical testing testing that open
52:22circuit voltage remember that you pull the panel out of service it’s not connected to anything and then you measure that voltage
52:28is it still what the manufacturer gave you it’s good to have an electrician do that because you’re still dealing with live
52:34dc voltage which can seriously shock you if you’re not careful ballasted this is another thing about
52:40roof systems and i’m going to actually go to that right now roof systemsRoof Mount Considerations
52:46so there’s a couple different ways to approach attaching these to the roof ballasted or directly connected or
52:53attached to the roof ballasted means you know they’re you’re just weighing them down so they’re not
52:58going to go anywhere with cinder blocks or just extra weights obviously that’s not going to work on a roof like this one that’s highly
53:04sloped or pitched but on a flat roof maybe ballasting is more cost effective this is where it comes back to the
53:10roofing material question about if you’re using a softer material like sbs styrene butadiene styrene
53:17and some of these softer materials on the roof they might not handle the ballasting very well and they might start breaking down you might need
53:23direct connections at that point but you definitely want to leave if you’re connecting to a roof
53:30uh making sure that there is that four to six inch air space between roofs the roof and modules for airflow because
53:36these do get hot and so we don’t want them just melting in place or breaking down just because there’s no place for air to
53:42to move um weatherproofing any holes in the roof itself to prevent leaks a
53:48lot of roofing companies you know work closely with the module um the module installers to make
53:54sure that they’re covered in the warranty for the roof but not always especially if you didn’t communicate clearly with that
54:01professional roofer so make sure you can discuss warranty
54:06inspection upon initial installation of these things and making sure that these cuts into the
54:12roof and these connections into the roof are made in such a way that there’s not going to be
54:17water leaking into the rooms in the building sloped roofs uh
54:22the report enroll report talks about this as well and that is on sloped roofs you get you can get more
54:29of direct access to the sun potentially because if you’re in the winter it’s at an angle however there’s a lot more
54:36cost associated with maintenance because you can’t really just walk up there anymore you have to have lifts and things so the report
54:42estimates some of the cost ideas including this one right different types of roofing thermoplastic ethylene polyvinylRepair Costs for Different Types of Roofs
54:50chloride bituminous this is straight out of that report as well asphalt different types of
54:57roofing materials and kind of the estimates that they’re seeing from all their data of how much it costs to repair this roof
55:03if something needs to be repaired with that solar panel and how to repair that part of the roof 20 bucks per meter square square meter
55:10think about that three feet by three feet 20 bucks 20 bucks 15 bucks 40 bucks it kind of varies by
55:16type and here’s how many hours it would take to repair one meter squared of that roofThe PV System – Other Components to consider!
55:23and finally i will close i know i only have five minutes left but i’m going to try to answer a few of your questions
55:30and in the meantime always feel free to ask more questions in a follow-up um
55:36in the email i’m going to send you and we can we offer a two-day classes right so i can only get so far into solar
55:42before we really need to spend more time uh take a two-day class so we’ll come to you and offer
55:47another photovoltaics class for you online or in person so one thing to consider is we’ve talked
55:52mostly about this right the solar panel array but there’s all the other um attached
55:58devices that we were mentioning combiner box which takes all the dc signals combines it into one
56:04disconnecting that dc which is important as part of the code requirements taking us to the breaker panel for dc
56:10that can break disconnect the solar from the rest of the system the inverter we talked about ac
56:15disconnects ac breakers and then the kilowatt hour meter which may or may not be a net meter and then going into the the home for
56:23um for use by our appliances but also out to the grid for us to pay back so there’s all sorts
56:29of devices this is just a quick taste of not only are we maintaining these but we’re maintaining one two three four five six
56:36seven plus different things as well and um highly recommend you read that nrel report to get a little bit more info and
56:42then reach out to us if you continue to have some more questions
56:47so um let’s see here
56:53for now i think we can really start seeing if you have any questions we’ve got a good amount of curiosity on theAre Your Questions Answered?
56:58line i apologize in advance can’t get to all the questions but um yeah we got we had this good question
57:04i’m i’m happy i was able to answer this one about where does that remaining energy go if the efficiency is so low
57:09and the answer is absolutely it all gets dissipated as heat so those 85 watts for every 100 watts
57:15let’s say goes up into the air as heat will there be a separate training for the rest of
57:20the components in a solar system yeah inverters batteries etc you know what based on demand we can
57:27definitely do stuff like that our company kind of specializes in electrical systems so inverters batteries
57:32i think it’s definitely something we can do is a further webinar topic by the way jade learning if any of you
57:38have taken electrical courses with jade they’re they’re offering a new solar powered class um some of you
57:44asking about uh some of the requirements for solar you know what’s required for installing this way
57:51or that way i would just answer that by saying there are a whole set of requirements in
57:57article 690 if you want to write this down 690 for solar-powered
58:02photovoltaic systems in the national electrical code so you know this this book is a thousand
58:07pages long you can spare yourself that unless you want some good reading but you can flip to chapter six of the
58:13nine chapters and go to chap uh article 690 and read all about the requirements
58:18from the national electrical code they have requirements for wire protection as you can imagine out in the elements they
58:24have requirements for the dc part of the circuit disconnects and switches and grounding and all that
58:29fun stuff um there’s there’s a lot to go into that in terms of coatings in terms
58:36of all that fun stuff hot spots typically be on an entire cell
58:43you would think it would be especially in these um monocrystalline cells which you know if one part’s getting hot it’s kind of
58:49spreading through the crystal structure for polycrystalline maybe it will be more piecemeal depending on kind of the
58:54jagged material here in my one minute remaining um you know this is a great question
59:03we can talk about environmental impacts so one one attendee is talking about um what is the solar industry doing to
59:10reduce the negative environmental impacts that come from the production of solar panels for instance right the silicon has to be
59:17mined out of the ground right i wish i could answer that in 30 seconds but unfortunately
59:23it’s a really good question and i can’t answer it all but but the industry and i’m sure the national renewable energy lab can attest
59:30there’s smart people all over the place looking at ways to get solar-powered materials
59:35created with less environmental impact and making sure that the environmental
59:42savings or the savings in let’s say greenhouse gases and that kind of thing during operation of the solar panel far
59:48outweighs the costs of mining it out of the ground and better yet
59:54the cost of mining silicon out of the ground to make a solar panel is hopefully can be made to be far less
1:00:00than what it takes to mine coal and natural gas which are the alternatives right to solar power so there’s all sorts of
1:00:07analysis going down from from a large scale perspective i’ve been part of those analyses before in previous
1:00:12work and there’s a lot of complexities there obviously as electricity is used by everyone you’re never more than you know
1:00:18one foot from an electrical panel at any time so just keep that in mind that it is
1:00:23being worked on and it’s kind of a something is better than nothing kind of approach it’s way
1:00:28better than the alternative but it’s not perfect either so there’s kind of a lot of opportunities for people to do more work with solar panels
1:00:35and improving them so thank you all for your great questions i again apologize in vance i can’t get to
1:00:41all of them but let’s definitely talk some more feel free to call this number up and and talk to us
1:00:47and see if we can answer any of your more questions and get you into more training opportunities for
1:00:52solar and for electrical and all these other great things so thank you so much for your time and have a great day