Inside Namasté Solar Electric: the "Grid-Tied Solar Photovoltaics" class
“Namasté Solar Electric” became a household word in February when founder Blake Jones took President Obama to the roof of Denver’s Museum of Science and Nature to see the solar panels Namaste had installed.
What a coup for the company’s profile and, indeed, for all those who recognize that a national focus on renewables will drive innovation and lower our carbon footprint as it builds energy independence and bolsters national security.
Jones’ brief blog on that watershed event is here:
http://www.cres-energy.org/blogs/blogs_Jones09feb.html
And since then, the north Boulder-based company has become a magnet for media looking for a good story and job seekers focused on employment that aligns with their personal values. “Being a part of the solution” has resonance for many Americans today and my classmates in CU’s Sustainable Practices program are living proof.
Several of my classmates were electrical engineers, others clearly yearned for the climbing harness and pitched roof, while a significant proportion were homeowners evaluating the technology. Apropos of Namasté’s focus on public policy changes that will grow the industry – the company has two full-time people on its roster of 50+ employees devoted to the task – one classmate was a planning commission member from Castle Rock looking to encourage solar PV in her town. The town of Superior was cited as particularly solar friendly and the planning commissioner took note.
Thomas Friedman’s column in today’s New York Times spells it out: the U.S. had better get its act together now with a national solar and renewable energy policy, because Germany, China and other countries are eating our future for lunch. Today. With mature, profitable industries such as oil getting massive subsidies from the government (read: taxpayers), it is sheer insanity that the U.S. continues to dither over a consistent, effective national policy to shape the market for our future energy needs. Read Friedman here:
http://www.nytimes.com/2009/09/16/opinion/16friedman.html
Well, the teachers and students in last weekend’s three-day-long “Grid-tied Solar Photovoltaics” class definitely “get it.” Lest I lapse into warm fuzzies, let’s be clear: this is a nuts-and-bolts (literally) class that addresses the design and installation of solar PV panels, from measuring shadows to wiring inverters. Forget singing Kumbaya my friends, these people are too busy with real solutions.
The class runs you through the working details of solar electricity, including concepts and applications, and the fundamentals of site analysis and system design down to a product-specific level. You will use an electric drill, a socket wrench and wire cutters and presumably vast, previously untapped areas of your brain. The latter is particularly true (for one journalist, at least) during a run-through of the National Electrical Code (NEC)’s equations for de-rating DC power and for safe wiring and system practices. Some of my classmates, however, leaned forward, eagerly. (Hey, whatever floats your boat...)
Before getting to the class itself, let’s take a glance at Namasté itself. Surely you’re curious?
I’ve met perhaps 10 of the company’s 50+ employees over the past month and just spent two days at their warehouse and offices in north Boulder. Let’s talk people first (job seekers take note): these folks are well-informed beyond their main roles at the company and they have well-rounded backgrounds, including education and community service here and abroad. (One gentleman mentioned that he’d had three rounds of interviews to win a job there, with one interview in the field.) Everyone is articulate about the solar value proposition and Namasté’s particular offerings. And they’re down-home. When all your people understand they’re on the front line and they represent the company as well as the CEO, you’re in business.
As a company, Namasté is an egalitarian organization that believes everyone on the team has a valuable perspective. The company sells a stake in itself to employees who so desire, making them “co-owners.” Executive pay is not disproportionate to that of the other owners and workers. Where once the decision-making process was run by consensus – everyone had to sign off – it has evolved to a democratic process of majority rules, according to Marci Leffingwell, a co-owner and sales and design specialist who participated in the class.
The company’s mundane warehouse and open offices on north Broadway reflect that this is a no-nonsense business. Namasté gets its bread-and-butter work done while devoting significant resources to preaching the solar gospel, being involved in education and community outreach and working for public policies that will benefit everyone in the industry – indeed, everyone in general. The company apparently desires to remain local – mostly metro Front Range – and maintain its modest scale, an exercise in sustainable management.
The warehouse and offices are, to the degree possible, energy efficient and made of recycled materials. Two solar PV arrays are in use; one is a roof-mounted array (four rows of eight panels), the other is a solar awning of eleven panels that shades the south-facing entrance. Together, they generate more than three-quarters of the facility’s electricity use.
So, these folks wear frikking halos, right? Nah. The joking on the job as we went about designing systems and then installing a solar PV array established that irreverence is alive and well here. And I personally was encouraged that, despite the complete absence of the f-bomb as we heaved to, there is a keg-erator in the warehouse with a locally made beer on tap.
Okay, now to the class. On the first morning, Stephen Kane, a co-owner and service director, ran us through the basics of electricity and the nature of DC (direct current) and AC (alternating current). Solar photovoltaic cells generate DC power and the other major system component involved – the inverter – translates that into AC power that ties to the home and the grid. DC is dangerous and involves more complex calculations to meet code, while AC is more forgiving because it alternates – electrons flow in one direction, then the opposite, in each cycle. In the U.S., our electrical grids and appliances use 60 Hz cycles.
“Grid-tied” means you sell electricity to the grid when you generate more than you use and draw when you need more than you generate. It is the most prevalent PV technology today simply because the market for solar is larger in urban grids and because stand-alone, power-storage technologies such as batteries require further innovation to drive widespread adoption. That, of course, is an over-simplified market generality; when electricity storage devices are advanced and cheap, some on the grid will want backup capabilities.
We learned that solar modules, aka panels (the typically rectangular assemblage of cells) operate best in cool weather and their efficiency drops as they get hot. Roof-mounted arrays typically have 4-6 inches of space between them and the roof for ambient air cooling. The year’s peak performance takes place in spring and fall, for temperature reasons.
In the afternoon, Chris Fox, another co-owner and sales/design specialist, ran us through the distinction between an array wired in “series,” or “strings,” akin to the Christmas light string where a single outage affects the whole, and “parallel,” where a series of panels are wired in parallel to reach the converter. Wiring in series produces voltages high enough to kick on the inverter each sunny day, but shade on one panel alone can kill total electricity production. The trick is to put together strings of panels and parallel wire them to the inverter, within the specs for the inverter. This is done using the National Renewable Energy Laboratory (NREL)’s PVWatts software and each panel and inverter manufacturer’s “string sizing” software.
Lauren Coyne, Namasté’s education and outreach manager, described the trade-offs of various products in the market. Higher efficiency panels cost more and may be appropriate when unshaded roof space is limited. Lower efficiency panels might be appropriate when space is not an issue. Coyne and Fox led us through the use of the “solar pathfinder,” a small, handheld device that ascertains the precise azimuth, or east-west orientation, for an array. Optimal in Colorado is 170 degrees, or just slightly east of south-facing. The tilt angle of an array is optimal at 40 degrees, which is synonymous with Boulder’s latitude.
But solar panels are efficient in a relatively wide swath beyond those optimal values and careful work will meet Xcel Energy’s requirement that an installed system be 90% efficient to qualify for its rebate program.
Ironically, there is tension between your beloved shade trees that cool and protect your home from storms and effective PV use. Blocking direct solar irradiation sharply curtails electricity production. That’s true even of the diffuse shadows created by tree branches in winter. That’s led Boulder to enact a shade law: you cannot go vertical with your building or landscaping if it blocks the sun on your neighbor’s property. Not incidentally, the solar pathfinder charts the impact to your roof of any shade-producing, nearby objects such as trees. If the shade on your roof obscures the array’s solar window from 9 am to 3 pm for a significant portion of the calendar year, Namaste recommends that you don’t install in that area.
The site analysis and system design aspect of the class established that several variables come into play. You need to plot out your available, shade-free roof space and orientation, determine your historical electricity use and production (or “off-set”) goals, and create a budget.
Then the class broke into groups, each assigned a problem to solve. With variables in hand -- different hypothetical roof sizes and alignments, measurable shade challenges, the percentage “offset” a client wanted to achieve and budget limits – we had to calculate and present design and product options.
Within minutes, given what we’d learned, the groups reported back to their Namasté taskmasters. Briefly, this involved a few calculations such as “derating,” or the loss of optimal value as DC energy is converted to AC, and “string sizing,” or how strings of panels are partnered with the proper size of inverter.
On Saturday, the class’ second day, we began installing an array of panels on a practice “roof” at ground level next to Namasté’s office/warehouse. The use of drills, wrenches and elbow grease was a welcome relief to the paper exercises.
We mapped an array to the available roof space, leaving distance to the roof peak for local code considerations or prudence (wind sheer and aesthetic concerns) and installation and service requirements (installers place an anchor for their harness on the peak). We also left a foot or so on all sides (again, for installation and service practicalities). Our collective intelligence led us indoors when thunder and lightning closed in.
On the class’ last day, Jon Ernst, co-owner and PV system designer, and Jason Sharpe, COO, lead technical designer and the company’s DC power guru (“DC is dangerous”), ran us through concepts in solar electricity. Perhaps suffice to say, this information is not easily or breezily summarized. We learned the standard specifications that are given on the back of each solar panel, the standard test conditions (STC) those specs are based on, a little of the physics explaining why silicon cells produce the most watts per dollar, how the National Electrical Code (NEC) treats solar, and other potentially mind-numbing topics made simple because Ernst and Sharpe (sounds like a law firm) have deep training and long experience.
We enjoyed quotes such as “volts shock, amps kill.” And, believe it or not, we learned how to wire an array to an inverter, using #10 USE-2 wire (panel to junction box to inverter) then #10 THWN (through a “runway,” or metal pipe, from inverter to main disconnect to the electric meter and the grid). (The number on wires denotes gauge, while the letters refer to the insulation-jacket type.)
Hard to believe we’d done it all in three days. As I contemplated slogans such as “This is your brain on solar electricity” – totally inspired, half scrambled – I took my leave a little early.
After all, I was due at The Outlook at the south end of town to cheer on Erik Boa & the Constrictors in the local International Blues Challenge. This terrific band won in the best band category and will head to Memphis in January to take their brand of blues to a national stage. Good work Erik!
And thanks to Heather Leanne Nangle at Namasté for helping with everyone's last names and titles.
What a coup for the company’s profile and, indeed, for all those who recognize that a national focus on renewables will drive innovation and lower our carbon footprint as it builds energy independence and bolsters national security.
Jones’ brief blog on that watershed event is here:
http://www.cres-energy.org/blogs/blogs_Jones09feb.html
And since then, the north Boulder-based company has become a magnet for media looking for a good story and job seekers focused on employment that aligns with their personal values. “Being a part of the solution” has resonance for many Americans today and my classmates in CU’s Sustainable Practices program are living proof.
Several of my classmates were electrical engineers, others clearly yearned for the climbing harness and pitched roof, while a significant proportion were homeowners evaluating the technology. Apropos of Namasté’s focus on public policy changes that will grow the industry – the company has two full-time people on its roster of 50+ employees devoted to the task – one classmate was a planning commission member from Castle Rock looking to encourage solar PV in her town. The town of Superior was cited as particularly solar friendly and the planning commissioner took note.
Thomas Friedman’s column in today’s New York Times spells it out: the U.S. had better get its act together now with a national solar and renewable energy policy, because Germany, China and other countries are eating our future for lunch. Today. With mature, profitable industries such as oil getting massive subsidies from the government (read: taxpayers), it is sheer insanity that the U.S. continues to dither over a consistent, effective national policy to shape the market for our future energy needs. Read Friedman here:
http://www.nytimes.com/2009/09/16/opinion/16friedman.html
Well, the teachers and students in last weekend’s three-day-long “Grid-tied Solar Photovoltaics” class definitely “get it.” Lest I lapse into warm fuzzies, let’s be clear: this is a nuts-and-bolts (literally) class that addresses the design and installation of solar PV panels, from measuring shadows to wiring inverters. Forget singing Kumbaya my friends, these people are too busy with real solutions.
The class runs you through the working details of solar electricity, including concepts and applications, and the fundamentals of site analysis and system design down to a product-specific level. You will use an electric drill, a socket wrench and wire cutters and presumably vast, previously untapped areas of your brain. The latter is particularly true (for one journalist, at least) during a run-through of the National Electrical Code (NEC)’s equations for de-rating DC power and for safe wiring and system practices. Some of my classmates, however, leaned forward, eagerly. (Hey, whatever floats your boat...)
Before getting to the class itself, let’s take a glance at Namasté itself. Surely you’re curious?
I’ve met perhaps 10 of the company’s 50+ employees over the past month and just spent two days at their warehouse and offices in north Boulder. Let’s talk people first (job seekers take note): these folks are well-informed beyond their main roles at the company and they have well-rounded backgrounds, including education and community service here and abroad. (One gentleman mentioned that he’d had three rounds of interviews to win a job there, with one interview in the field.) Everyone is articulate about the solar value proposition and Namasté’s particular offerings. And they’re down-home. When all your people understand they’re on the front line and they represent the company as well as the CEO, you’re in business.
As a company, Namasté is an egalitarian organization that believes everyone on the team has a valuable perspective. The company sells a stake in itself to employees who so desire, making them “co-owners.” Executive pay is not disproportionate to that of the other owners and workers. Where once the decision-making process was run by consensus – everyone had to sign off – it has evolved to a democratic process of majority rules, according to Marci Leffingwell, a co-owner and sales and design specialist who participated in the class.
The company’s mundane warehouse and open offices on north Broadway reflect that this is a no-nonsense business. Namasté gets its bread-and-butter work done while devoting significant resources to preaching the solar gospel, being involved in education and community outreach and working for public policies that will benefit everyone in the industry – indeed, everyone in general. The company apparently desires to remain local – mostly metro Front Range – and maintain its modest scale, an exercise in sustainable management.
The warehouse and offices are, to the degree possible, energy efficient and made of recycled materials. Two solar PV arrays are in use; one is a roof-mounted array (four rows of eight panels), the other is a solar awning of eleven panels that shades the south-facing entrance. Together, they generate more than three-quarters of the facility’s electricity use.
So, these folks wear frikking halos, right? Nah. The joking on the job as we went about designing systems and then installing a solar PV array established that irreverence is alive and well here. And I personally was encouraged that, despite the complete absence of the f-bomb as we heaved to, there is a keg-erator in the warehouse with a locally made beer on tap.
Okay, now to the class. On the first morning, Stephen Kane, a co-owner and service director, ran us through the basics of electricity and the nature of DC (direct current) and AC (alternating current). Solar photovoltaic cells generate DC power and the other major system component involved – the inverter – translates that into AC power that ties to the home and the grid. DC is dangerous and involves more complex calculations to meet code, while AC is more forgiving because it alternates – electrons flow in one direction, then the opposite, in each cycle. In the U.S., our electrical grids and appliances use 60 Hz cycles.
“Grid-tied” means you sell electricity to the grid when you generate more than you use and draw when you need more than you generate. It is the most prevalent PV technology today simply because the market for solar is larger in urban grids and because stand-alone, power-storage technologies such as batteries require further innovation to drive widespread adoption. That, of course, is an over-simplified market generality; when electricity storage devices are advanced and cheap, some on the grid will want backup capabilities.
We learned that solar modules, aka panels (the typically rectangular assemblage of cells) operate best in cool weather and their efficiency drops as they get hot. Roof-mounted arrays typically have 4-6 inches of space between them and the roof for ambient air cooling. The year’s peak performance takes place in spring and fall, for temperature reasons.
In the afternoon, Chris Fox, another co-owner and sales/design specialist, ran us through the distinction between an array wired in “series,” or “strings,” akin to the Christmas light string where a single outage affects the whole, and “parallel,” where a series of panels are wired in parallel to reach the converter. Wiring in series produces voltages high enough to kick on the inverter each sunny day, but shade on one panel alone can kill total electricity production. The trick is to put together strings of panels and parallel wire them to the inverter, within the specs for the inverter. This is done using the National Renewable Energy Laboratory (NREL)’s PVWatts software and each panel and inverter manufacturer’s “string sizing” software.
Lauren Coyne, Namasté’s education and outreach manager, described the trade-offs of various products in the market. Higher efficiency panels cost more and may be appropriate when unshaded roof space is limited. Lower efficiency panels might be appropriate when space is not an issue. Coyne and Fox led us through the use of the “solar pathfinder,” a small, handheld device that ascertains the precise azimuth, or east-west orientation, for an array. Optimal in Colorado is 170 degrees, or just slightly east of south-facing. The tilt angle of an array is optimal at 40 degrees, which is synonymous with Boulder’s latitude.
But solar panels are efficient in a relatively wide swath beyond those optimal values and careful work will meet Xcel Energy’s requirement that an installed system be 90% efficient to qualify for its rebate program.
Ironically, there is tension between your beloved shade trees that cool and protect your home from storms and effective PV use. Blocking direct solar irradiation sharply curtails electricity production. That’s true even of the diffuse shadows created by tree branches in winter. That’s led Boulder to enact a shade law: you cannot go vertical with your building or landscaping if it blocks the sun on your neighbor’s property. Not incidentally, the solar pathfinder charts the impact to your roof of any shade-producing, nearby objects such as trees. If the shade on your roof obscures the array’s solar window from 9 am to 3 pm for a significant portion of the calendar year, Namaste recommends that you don’t install in that area.
The site analysis and system design aspect of the class established that several variables come into play. You need to plot out your available, shade-free roof space and orientation, determine your historical electricity use and production (or “off-set”) goals, and create a budget.
Then the class broke into groups, each assigned a problem to solve. With variables in hand -- different hypothetical roof sizes and alignments, measurable shade challenges, the percentage “offset” a client wanted to achieve and budget limits – we had to calculate and present design and product options.
Within minutes, given what we’d learned, the groups reported back to their Namasté taskmasters. Briefly, this involved a few calculations such as “derating,” or the loss of optimal value as DC energy is converted to AC, and “string sizing,” or how strings of panels are partnered with the proper size of inverter.
On Saturday, the class’ second day, we began installing an array of panels on a practice “roof” at ground level next to Namasté’s office/warehouse. The use of drills, wrenches and elbow grease was a welcome relief to the paper exercises.
We mapped an array to the available roof space, leaving distance to the roof peak for local code considerations or prudence (wind sheer and aesthetic concerns) and installation and service requirements (installers place an anchor for their harness on the peak). We also left a foot or so on all sides (again, for installation and service practicalities). Our collective intelligence led us indoors when thunder and lightning closed in.
On the class’ last day, Jon Ernst, co-owner and PV system designer, and Jason Sharpe, COO, lead technical designer and the company’s DC power guru (“DC is dangerous”), ran us through concepts in solar electricity. Perhaps suffice to say, this information is not easily or breezily summarized. We learned the standard specifications that are given on the back of each solar panel, the standard test conditions (STC) those specs are based on, a little of the physics explaining why silicon cells produce the most watts per dollar, how the National Electrical Code (NEC) treats solar, and other potentially mind-numbing topics made simple because Ernst and Sharpe (sounds like a law firm) have deep training and long experience.
We enjoyed quotes such as “volts shock, amps kill.” And, believe it or not, we learned how to wire an array to an inverter, using #10 USE-2 wire (panel to junction box to inverter) then #10 THWN (through a “runway,” or metal pipe, from inverter to main disconnect to the electric meter and the grid). (The number on wires denotes gauge, while the letters refer to the insulation-jacket type.)
Hard to believe we’d done it all in three days. As I contemplated slogans such as “This is your brain on solar electricity” – totally inspired, half scrambled – I took my leave a little early.
After all, I was due at The Outlook at the south end of town to cheer on Erik Boa & the Constrictors in the local International Blues Challenge. This terrific band won in the best band category and will head to Memphis in January to take their brand of blues to a national stage. Good work Erik!
And thanks to Heather Leanne Nangle at Namasté for helping with everyone's last names and titles.
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