Category Archives: Residential Storage

An Inside Look At The Components That Go Into A Tesla Solar Roof Installation

Originally published on CleanTechnica

July ushered in the start of the real action for our Tesla solar roof, as the installation kicked into high gear. The first materials arrived at the house and the team prepared to install the solar roof on our new home. Before we get into the installation, let’s talk about the components that make up of one of Tesla’s solar roofs.

Tesla solar roof installation. Image credit: Chuck Field

Many of the components and processes used in installing a Tesla solar roof are from the traditional roofing industry, which makes sense. The solar roof still fundamentally has to perform all of the same functions of a normal dumb roof before its ability to generate power matters. It also includes many of the same components as a traditional bolt-on solar system, with rooftop wiring, inverters, safety devices, and the like.

To run the numbers on a Tesla Solar Roof, Solar, or Powerwall for yourself in about two minutes, use my referral code (https://ts.la/kyle623) and you can save $100. Tesla is just one of many solar providers out there, so don’t go with Tesla just because I did. Remember, I compared offerings from Sunrun, Sun Power, sonnen, and Tesla before making what I felt was the best decision for my family and recommend you do the same.

Underlayment

A Tesla solar roof installation starts with the installation of a waterproof underlayment. Tesla uses Firestone’s CLAD-GARD SA-FR, a standard roofing underlayment for metal roofs. This product provides a waterproof foundation for any roof while also providing a skid-resistant surface for the installers to walk on while installing the more complex parts of the roof. This is the white material in the photo above.

Metal Framing

After the underlayment goes down, Tesla’s crew frames up the roof with metal. A metal trim wraps around the entire roof edge as well as along every peak and valley in the roof structure. In the valleys of the roof, the metalwork provides the drainage for any precipitation and debris. Up at the peaks of the roof, it provides protection, funneling any precipitation onto the tiles or surfaces below, which ultimately escort it off the roof.

Tesla solar roof with copious amounts of metal work framing the roof. Image credit: Kyle Field | CleanTechnica

Tesla makes all of its own metal products for the solar roof, so all of these components are specific to the Tesla solar roof. Word on the street is that these are all currently made in the Bay Area, but that likely won’t be the case as Tesla ramps up production after locking in the design of version 3 of its solar roof tiles.

Roof Tiles

The star of the show in the solar roof install is obviously Tesla’s solar roof tiles. These come in two flavors: 1) tiles with solar cells sandwiched between two pieces of tempered glass that produce power, and 2) glass tiles. Roof tiles with solar cells in them are called PV Tiles and are the fundamental building block of any Tesla solar roof. They arrive on site in pre-wired, pre-mounted bundles of 3 tiles in a row, called PV Modules.

A pallet of Tesla PV Module roof tiles. Image credit: Kyle Field | CleanTechnica

Each PV Tile has a production capacity of just over 8 watts each, translating to 25 watts for a full 3-tile PV Module. Assembling the tiles together into PV Modules at the factory has multiple benefits, with the first and foremost being a reduction in the amount of effort and time that’s required to install a solar roof. This helps Tesla deliver a faster turnaround time, means less time for a customer’s home sitting there without a roof, and keeps labor costs down.

Using PV Modules also reduces the number of on-site wiring connections that need to be made, allowing Tesla to control the quality of more potential points of failure in the roof system at the factory. PV Modules come with the joints between the three tiles pre-sealed, resulting in what is surely a higher quality, more consistent seal that what can be guaranteed with a field installation. Each PV Tile comes with its own set of built-in c-clip mounts and stand-offs that hold the top of the tile off of the roof, transferring any weight from above to the roof surface below while also serving to set the correct angle to allow water to run down the roof.

Tesla calls the non-producing tiles Roofing Tiles, which are simply made from a single sheet of tempered glass. These come from the factory as single tiles as well as bundled into Roofing Modules comprised of 3 glass tiles. Tesla uses these on sections of the roof that are not wide enough for a block of solar tiles and for use along the seams of the roof. To ensure a clean fit at the seams, Tesla’s team simply cuts the tiles to match the angle of the seam they will butt up against.

A cut Roofing Module with mounting bricks in the background. Image credit: Kyle Field | CleanTechnica

Mounting Bricks

Tesla has packed an impressive amount of functionality into each single PV Module, and the mounting bricks are the other half of the system that makes it easy for Tesla’s installer to secure the PV and Roofing Modules to the roof. Tesla’s mounting bricks come in standard and drained configurations.

Tesla solar roof installation. Image credit: Chuck Field

Standard mounting blocks allow the tile below it to mount to it, but also allow the panel above it to clip to it, thanks to a healthy dose of industrial grade plastic hook and loop. The trailing edge of the panel above the mounting brick has another strip of this fabric, resulting in a very secure bond. Check it out in the video below:

Drained mounting bricks include a channel that helps water drain in the proper direction between each of the PV Modules or where they butt up against a Roofing Tile or Roofing Module. They still allow adjoining modules to mount to them with their c-clips, but with the added benefit of funneling water down the roof.

A Tesla solar roof tile clipped onto a drained mounting block. Image credit: Kyle Field | CleanTechnica

The Electrical System

Each PV Module is connected to the solar roof wiring string via standard solar MC connectors that come pre-installed from the factory. These strings then connect down through the roof via a series of electrical pucks mounted and sealed to the roof. Tesla is required to install a Rapid Shutdown Device (RSD) within 5 feet of every solar array, so they are typically installed up in the rafters near the roof.

The wiring in an array of Tesla solar roof tiles. Image credit: Tesla

On the inside of the house, the pucks sprout bare wires that connect to one of a handful of these Delta Rapid Shutdown Devices, shown as a small grey box to the right of the rooftop wiring in the image above. Outputs from the RSDs are fed down to a pair of Delta inverters that convert the DC power from the roof down into the AC power that all the electrical goodies in the home want.

From there, the wiring configuration varies depending on whether Powerwalls are being installed or not. We are installing two Powerwalls, so we’ll talk through the essential loads wiring configuration. For our house, we do not have anything running on gas, so all our appliances, cooking, and heating are electric. Add to that two electric car chargers and a spare for guests and our loads were just too large to cram into a single 200 amp electrical sub-panel.

After all the load calculations were done, we opted to pull a few of the larger, less critical loads off of the Powerwall battery backup and just backup the “essential” loads in our house. The image below shows a single, undersized inverter and diminutive supporting boxes. Every single one of these boxes/devices in our system is twice as large as shown here, with the exception of the Tesla Powerwall (though, technically, we do have two of those).

Image credit: Tesla

The two Powerwalls provide backup power to everything on our 200 amp sub-panel, while the remaining loads in our home — our electric oven and two of our car chargers — will be relegated to the 400 amp main panel.

The Tesla Backup Gateway provides communication to the Tesla Mothership and can automagically disconnect the home from the grid in the event of a power outage. Doing so engages the Powerwalls to provide power to all of the essential loads in the sub-panel, while being replenished by the rooftop solar system when the sun is out.

That’s an overview of the components in a Tesla solar roof system. We’ll dive into the system more in future articles, so stay tuned for a first look at this hot new clean tech.

To run the numbers on a Tesla Solar Roof, Solar, or Powerwall for yourself in about two minutes, use my referral code (https://ts.la/kyle623) and you can save $100. Tesla is just one of many solar providers out there, so don’t go with Tesla just because I did. Remember, I compared offerings from Sunrun, Sun Power, sonnen, and Tesla before making what I felt was the best decision for my family and recommend you do the same.

Why Tesla’s Solar Roof Is A Bargain, 53% Of The Price Of A Roof + Electricity

Image courtesy: Tesla

Originally published on CleanTechnica

When Tesla CEO Elon Musk unveiled the company’s Solar Roof tile system back in 2016, he boldly proclaimed that it would cost less than buying a roof and electricity. Since then, we have not seen any data to support his claim, until now.

I signed a contract with Tesla for the installation of a new Tesla Solar roof tile system and have unpacked the details, good and bad, from the contract in a series of articles. To kick things off, I will start by comparing the cost of the system against Elon’s claims to see if a Tesla Solar Roof tile system is actually cheaper than buying a roof and the power generated by the system over its life.

One Roof To Rule Them All

An accurate comparison requires an accurate baseline to be used for the cost of electricity and the cost of a new roof. Getting a new roof installed can range from $10,000 to $50,000, depending on the material used. Composite shingle roofs and tile roofs are more cost effective, but do not have the same durability as a Tesla Solar Roof with its tempered glass tiles. Tesla’s Solar Roof  is comprised of, “Glass solar tiles are so durable they are warrantied for the lifetime of your house, or infinity, whichever comes first.”


The only roofing product on the market that comes close to this bold proclamation is a metal roof with an expected 50 year life. This is an important comparison to understand because just looking at the Tesla Solar Roof as simply the covering for the home already sets it apart from most common roofing products. It is a high-end roof, even without the solar aspect. This is not a justification for a higher price, but it is simply the reality of buying a roof that lasts.

The Tesla Solar Roof is not a typical roof, and that is highlighted in the fact that it comes with two different guarantees. The first is for the solar production from the roof. The solar production from the Solar Roof is guaranteed for 25 years. This protects the buyer from subpar solar cells, cells failing, or other factors that impact the electrical generation from the system. Such a guarantee is standard across the solar industry. The second warranty is for the physical roof structure. Because the Tesla Solar Roof is a building-integrated photovoltaic (BIPV) system, in addition to generating power, it also must serve as the physical roof for the house. As a roof, the Tesla Solar Roof is warrantied for infinity or the life of the home, whichever comes first.

To ensure accuracy, I went out and got bids for the job from 5 real local contractors in Southern California. This was not a hypothetical exercise, as we are in need of a new roof and were actively pursuing both options to determine which was a better fit for our family. Bids were made based on actual permitted architectural drawings of the roof, with all associated wrinkles and warts. After receiving all of the bids, I took the average price from all 5 contractors and used that as the baseline cost for a comparable roof installation. That came to $37,865.80 for a new metal roof.

Electricity By Any Other Name

Musk and his team of energy engineers at Tesla were not simply trying to build a better roof. They were ultimately trying to build a solar product that would help the masses to adopt solar because it was easier, cheaper, higher quality, and better looking. That is a tall order to fill, by any measure.

On the cost side of the equation, it is a simple matter of taking the cost of electricity from the U.S. Energy  Information Administration (EIA) and extrapolating that price out over 25 years. I used the most recent cost of residential electricity in California of 19.3 cents/kWh (March 2019) and extrapolated that out using a conservative 2% annual increase. For parity, I priced the system out using the production of the solar system, following the maximum degradation noted by Tesla. Over the 25 year warrantied life of the solar production from the system, the Solar Roof system should generate $73,436.14 worth of electricity.

Sizing The Solar Roof

We do not have a gas line running to our home, so everything in the home runs on electricity. We also have two electric vehicles that pull the vast majority of their electricity from our home. To offset as much of this consumption as possible, we are installing the largest Tesla Solar Roof tile system that our roof can handle.

System sizing on a Tesla Solar Roof is done differently than traditional solar systems, where the number of solar panels used depends on the need and roof capability. Because a Tesla Solar Roof has to serve as a physical cover for the house as its primary function, tiles must cover the entire surface. To size the system, Tesla has developed tiles that have solar cells and tiles that do not — and they all look essentially the same. For smaller systems, Tesla simply uses fewer tiles containing the actual solar cells.

Image courtesy: Tesla

The Tesla Solar Roof for our home has solar cells in every location possible. There are some areas around the edges of the roof and near the hips and joints without cells, but every other surface is setup to produce power. The primary surface of our roof faces south, which is ideal for solar production, but the configuration we are using utilizes the north-, east-, and west-facing roof surfaces as well. That does indeed maximize our solar generation, but results in a lower yield from the system compared to a system with all active tiles facing south.

The Data

All told, Tesla was able to fit a 10.59kW system in our roof, which it expects will produce 13,126 kWh in its first year of operation. This is the equivalent size of a system of 32 x 330 watt solar panels! The system, which I’ll remind you also serves as the roof for our home, came out to $70,375.23 before rebates and $58,603.04 after rebates. Compared to the cost of a metal roof, the Tesla Solar Roof was $20,737.24 more.

Translating this data into nerd-speak, aka an Excel spreadsheet, we can see that the cost of installing a metal roof and simply buying the equivalent of the electricity produced by the Tesla Solar Roof system would equal $111,301.94, whereas the Tesla Solar Roof is only $58,603.04. These are not hypotheticals or mythical numbers, just a simple summary of expenses in two different scenarios over 25 years. Said another way, the Tesla Solar Roof is 52.7% of the cost of installing a comparable roof and just buying power from the utility.

What About A Composite Shingle Roof?

Image courtesy: Tesla

Costing out a Tesla Solar Roof versus a metal roof is interesting, but that’s still a really expensive roof. Musk said at the company’s annual shareholder meeting on June 11th, 2019, that the Solar Roof team was really pushing to beat even the ubiquitous composite shingle roof. Using the single estimate we received for a composite shingle roof for our house at a mere $12,000, the Solar Roof system still comes out on top.

We can use the same $73,436.14 for the value of the electricity produced and $12,000.00 for the composite shingle roof for a total of $85,436.14. That includes the cost of electricity over the life of the system from the utility and the physical composite shingle roof. Compared to the $58,603.04 for the Solar Roof, composite shingle is already more expensive here in Southern California.

In fact, even if I throw in the roof itself as free, the Solar Roof is cheaper than simply buying power from the utility here in California, for a savings of almost $15,000 over 25 years. It won’t make or break your retirement, but it is impressive to see that the Solar Roof is already holding its own against roofing materials of any type in California. In fact, that is conveniently close to the installed price of two Tesla Powerwalls, so throw those in for some extra resiliency and call it a day.

The payback time for the Solar Roof will vary state by state and utility by utility, so be sure to run your own numbers before pulling the trigger on your own system. We spent months looking into this topic. Check back at CleanTechnica for more analysis of the Tesla Solar Roof system as the installation of our system progresses.

If you are in the market for a Tesla, find someone locally who you know (like, someone you know in real life) and use their referral code. If you don’t know anyone with a Tesla, go find someone at your local Supercharger and try not to be a creep and ask them for their referral code (they won’t mind). If that doesn’t work, ask a co-worker or a distant relative, post on Facebook or Twitter, or just hit up Google. If all of that fails and it’s an odd-numbered day and not too sunny out, you can use my Tesla referral link to get 1,000 miles of free Supercharging, I guess. Here is my referral code: http://ts.la/kyle623

The Chevy Bolt & The Tesla Model 3: The Solar-Powered Restoration of American Energy Independence

Originally published on CleanTechnica

July 4th is Independence Day in the United States, and as with similar holidays in countless countries around the world, it is the perfect occasion to reflect on what it means to be independent. One key aspect of independence today is intimately tied into energy. How many countries around the world have found themselves economically enslaved to the energy economics inherited from past generations?

The US is the largest consumer of oil on the planet by a long margin, consuming more oil than any other country, regardless of population. While the US is also the largest “producer” of oil, it does not produce enough oil to satiate its seemingly endless thirst for it.

The capitalist country is embattled with modern-day oil barons fighting for lower fuel efficiency standards while climate change believers fight to raise fuel efficiency standards, enact a universal carbon tax, and work to create incentives for battery electric vehicles. The gridlock of the past took a turn for the worse with the Trump administration, which continues to plod forward in the mindless push to unshackle the American capitalist machine from the trio of perceived anchors that are the Clean Air Act (of 1970), the Clean Water Act (of 1972), and the much more recently added Clean Power Plan (of 2014).

In the face of this political uncertainty, a few beacons of hope have emerged, shining out of the dust of the recently fallen environmental protections. They give us hope for a future where our children and grandchildren can breath clean air, can drink water that is free of heavy metals and toxins. A future where the vehicles that move us from place to place move silently around, powered by clean technologies and whirring electric motors.

The Chevrolet Bolt, which launched in December 2016, and the Tesla Model 3, which will be delivered to its first customers later this month, are the first vehicles of a new generation of long-range, affordable electric cars that carry the keys to unlocking the most American of all values — true energy independence. For the first time in many, many decades, America has within its grasp the ability to harvest electricity from the wind and sun that will not run dry — using power systems that emit no pollution into the air and require minimal emissions to manufacture.

The shift from fossil fuel–fired vehicles to electric vehicles presents a rare opportunity for any country in the world to catalyze a paradigm shift in energy generation. The opportunity to convert to locally produced energy brings along with it the possibility to keep millions and billions of dollars of energy spending inside the country. For the United States, this means weaning itself off of the ill-adopted relationships with countries around the world that have failed to move forward adopting minimum standards for human rights. For many nations in Eastern Europe, the opportunity to throw off the shackles from oppressive regimes that have for too long throttled the supply of energy as a means of controlling the economies of those less endowed with natural resources has the potential to reinvigorate the people and catalyze a positive change in these countries.

Clearly, these changes are not being led solely by two vehicles, but these vehicles embody the broader movement that is only now reaching its climactic moment in history. Affordable electric vehicles let the average person purchase a vehicle that has the range to make 99% or more of all trips possible with an electric vehicle. When combined with the fact that electric vehicles are also cheaper to drive on a cost of fuel per mile basis, it starts to get interesting — my wife and I have saved nearly $2,000 in 2½ years of owning our first electric vehicles versus the cost of gasoline.

Electric vehicles also require significantly less maintenance, with thousands of fewer moving parts than their fossil fuel–fired counterparts, resulting in even more savings. Electric vehicles are much quieter to drive, and without the controlled explosions of a fossil fuel engine under the hood, don’t vibrate their passengers to death. Removing that combustion engine from the vehicle and replacing it with an electric motor also allows for completely new vehicle designs that have resulted in the Tesla Model S being rated the safest vehicle to ever be tested by the NHTSA, with the Tesla Model X coming in at number two — a ranking unheard of for a sport utility vehicle. The Chevy Bolt received top honors for its safety results as well, recently being selected as an IIHS Top Safety Pick.

Roll that all together with extreme performance and supercar 0 to 60 times and electric cars start to look appealing to people from all walks of life. Until these two cars rolled onto the scene, these benefits were only accessible to those who were willing to compromise on range with a ~100 mile electric vehicle or those with the finances to throw down $60,000 or more for a Tesla.

Driving an electric vehicle is great, but here’s where it gets interesting: Electric vehicles unlock much more than that. A core American value — and if we’re honest, a core human value — is the desire to not be dependent. Electric vehicles tap directly into that with the ability for homeowners, property owners, and many people around the world to install solar or wind on their residence to generate all the power their homes, businesses, and vehicles will use. The solar installation on my rooftop generated enough power last year to completely power our home and one of our electric vehicles. Another couple of panels and we will be generating the vast majority of the power we use in our lives on our roof. That is straight out of a science fiction novel but it is a true possibility for billions of people around the world today … and it gets even better than that.

With the massive improvements in production and scale that have been made over just the last 10 years, solar and wind are now extremely cost competitive — even beating out the competition in many areas of the world … today … right now. That’s right, you can create this utopian lifestyle today … and save money while you’re doing it.

That is the beauty of the paradigm shift that is occurring right now. We are living through an historic transition that our grandchildren will read about as the turning point in energy economics, globally. Entrenched trillion-dollar industries will crumble in decades along with the household-name companies that operate within them. Amidst the rubble, new companies, new individuals, and new nations are rising to the forefront of the discussion as leaders in never-before-seen industries that bring with them new possibilities for economic freedom and energy independence.

Transitions of this magnitude are apparent from the early birthing pains that manifest themselves in the form of federal policy debates, vicious catfights over government incentives, kickbacks, and tax breaks. The transitions are rarely fair, but with so much at stake, bloodshed on both sides is to be expected.

Rolling back to where we started, what seems like a domino effect of toppling regulations led by industry insiders that have been put in charge of the agencies that formerly regulated their industries have left many dumbfounded. The foundations of American environmental protections have been stripped bare in a matter of weeks. But all is not lost. The brazen disregard for the charter on which the Environmental Protection Agency was founded has woken millions from the enchanted slumber, just as Rip van Winkle awoke after many years of sleep into a frenzy.

The people of this great nation and many more around the world demand that the governments they voted into place protect their most fundamental rights to clean air and clean water. The catalyst could not have come at a better time, as affordable electric vehicles and cost-saving solar and wind generation allow individuals to cut the cord from the very capitalists who now move to enslave the population.

It is time to rise up and regain the independence that our ancestors fought for in years past, but this time we fight against those in charge in our own nation. The time is now to go test drive an electric vehicle. If that’s not enough time to get a feel for life with an electric vehicle, rent or borrow one. Services like Turo and Maven are lowering the bar to get into an electric vehicle just as the Chevy Bolt has and the Tesla Model 3 soon will for hundreds of thousands more people around the world.

If renting isn’t an option, it may be time to step up the game and steal one … or, rather, get a steal of a deal on one at a local dealership. While you’re at it, don’t forget that to really, truly cut the cord takes a little more work to ensure that the power you’re pumping into your vehicle every night comes from renewable sources as well, preferably from a solar installation or wind turbine on your property.

That, my friends, is what it truly means to be independent. Celebrate yours by taking action today. The future is electric. The future is now!

Residential Energy Pilot Explores Use Of Storage To Balance Neighborhood Solar Generation

Originally posted on CleanTechnica

A new residential energy storage pilot seeks to better understand how batteries installed in homes can be used at the neighborhood level by grid operators to absorb solar power generation excesses during the day and discharge them when needed later in the day.

A partnership between battery manufacturer Moixa, electricity distributor Northern Powergrid, and the community energy company Energise Barnsley aims to put the idea to the test with a new pilot. Specifically, 40 homes will have Moixa lithium-ion batteries installed, including 20 x 2 kWh batteries and another 20 x 3 kWh batteries.

Simon Daniel, CEO of Moixa, said:

“Solar homes with batteries can halve their electricity bills, and this solution will become increasingly popular as costs of storage and PV fall.

“We are working closely with Northern Powergrid and this project will deliver insights to develop incentives which we hope will allow us to roll out solar plus storage to tens of thousands of homes in their region, by creating a business case for homeowners to invest and also by increasing the number of solar connections allowed on each substation.”

These 40 batteries and homes will be linked into a Virtual Power Plant (much like what Next Kraftwerk is doing today but on a smaller scale) which the utility can then utilize to absorb power when solar production is peaking. Conversely, at night when the sun isn’t shining on all those glorious solar panels, or anytime demand exceeds production, the utility can tap into this Virtual Power Plant to supply power to the grid.

neighborhood

Most of the homes in the pilot already have photovoltaic (PV) solar installed (30 of the 40 homes) which will allow the pilot operators to better understand how residentially installed solar PV can play well with residentially installed lithium-ion batteries.

In this pilot, the batteries will be installed at no cost to the residents, with all funding provided by Northern Powergrid in an effort to support the masses of solar being deployed by Energise Barnsley.

Andrew Spencer, System Planning Manager for Northern Powergrid, said:

“This partnership is one of a number of ways we’re working to explore innovations that can benefit our customers and the communities we serve.

This pilot probes some of the potential solutions for problems grid operators around the world are quickly encountering as more residential PV solar is brought online and as battery prices continue to drop.

neighborhood

Does it make more sense to install and subsidize solar at the utility level or residential? Is storage better for the grid at the utility scale or residential, or when residential installations are pooled together into a virtual power plant?

The future for residential storage and PV solar is packed with opportunity and it’s great to see progressive utilities and energy companies working together so closely with manufacturers like Moixa on neighborhood-scale pilots like this to work out the kinks.

Source: Moixa Press Release and Solar Power Portal UK

Images Credit: Moixa

If you are looking to purchase a new Tesla, feel free to use my referral link (here) which will save you $1,000 on the purchase while also helping me to write better content for the site.