Remote site assessment cuts solar design time, costs (about $850 per install)

Aurora_remote assessment

There are some solar installation costs we can’t control, such as the tariffs imposed on the industry this year. But when it comes to cutting soft costs, which now comprise more than half of the cost of a solar installation, installers have a valuable tool in their tool kits: remote site assessment and design. NREL has estimated that solar design software that supports remote shading analysis can save installers $0.17/W per 5-kW system (~$850 per install).

Samuel Adeyemo and Christopher Hopper experienced directly how time-consuming and laborious solar design can be when they partnered on a commercial solar installation to power a school in Kenya in 2012. Installing the system took only a few weeks, but designing the system from across the world required months of planning. After talking to other solar installers, Adeyemo and Hopper realized time-intensive solar design processes were a common struggle.

With the goal of providing a more efficient way to design solar projects while maintaining precision and accuracy, they set about building Aurora Solar in 2013. Today, tools like Aurora’s solar design software are modernizing the design process and offering significant benefits to installers that utilize them.

Save time, effort and money

One of the most tangible benefits of using solar design software is the time and money saved from reduced truck rolls. Traditionally, site visits have been an important step in the solar design and sales process, as a starting point for installers to accurately assess the shading on the roof and determine the appropriate PV system size.

When you or your team have to spend hours driving to prospective customers’ homes and businesses, climbing on the roofs and taking manual measurements, it can be costly—especially during the pre-sale stage. However, with software that enables you to get a detailed understanding of the project site as well as the solar access and shading, you can drastically reduce the need for costly site visits.

Residential installer Solarponics experienced this benefit firsthand. After switching to Aurora for their solar designs, the company has been able to reduce their pre-sale site visits by 90 percent while doubling installations and keeping their closing rate constant.

Improve sales with faster proposal turnaround times

Streamlining your solar design process through remote site assessment also offers important sales benefits. Being able to quickly send an accurate design and quote for a customer, rather than waiting on a site visit, can make a significant difference in closing the sale.

Hans Frederickson, owner of Cascadia Solar, learned this when a company used remote site assessment to close a deal with one of his prospective customers while he was completing his onsite assessment. Soon after that experience, Cascadia Solar switched to remote site assessment and now can send customers a quote within an hour of talking with them on the phone, their solar sales have doubled month over month and more than doubled year over year.

Having a more efficient assessment and design process also makes it possible to pursue leads that might previously have been too costly. “It used to be that proposals were so time-consuming that I would focus on carefully qualifying each lead, but Aurora has allowed us to respond in a much more effective way to every solar lead we get,” says Frederickson.

Bankable accuracy

Of course, in order for remote site assessment to truly be valuable, your solar design, production and bill savings estimates must be accurate and precise to avoid change orders down the line. Thankfully, with the application of cutting edge technologies, remote solar design tools like Aurora offer accuracy that companies can be confident putting their name behind. NREL has validated the accuracy of both Aurora’s performance simulations and its remote shading analysis, which was found to be statistically equivalent to onsite measurements.

Rebate authorities around the country, such as CT Green Bank, NYSERDA, and the Energy Trust of Oregon, accept Aurora’s remote shade reports as an acceptable replacement for time-consuming and costly onsite inspections previously required when applying for rebates.

Data on change orders: Cost and prevalence

Aurora aims to give installers the tools to design and sell better solar, including reducing errors that lead to change orders. Recognizing that there is limited data on the prevalence and cost of change orders in the industry, Aurora surveyed solar professionals about the impact of change orders in a recent webinar. Download our data on change order cost and prevalence to see how your experience stacks up against others in the industry.

— Solar Builder magazine

AlsoEnergy purchases Draker and is transitioning customers to its platform

alsoenergy

We couldn’t locate a news announcement about this, but according to an email sent to Draker customers, Draker is now a part of AlsoEnergy.

“AlsoEnergy has signed a letter of intent to purchase the assets of Draker Energy, including intellectual property, customer lists, and source code. AlsoEnergy is now the only supplier of Draker products, services, and support.”

The email to Draker customers noted the following as part of the Draker Continuity Program:

• Continued login access for Draker customers at https://draker.us
• Uninterrupted data collection and agency reporting related to Draker monitored assets
• AlsoEnergy will honor all previously paid monitoring license terms and agency reporting agreements
• Free migration to AlsoEnergy’s PowerTrack platform for all Draker sites, including historical data and configurations along with training and support
• Full integration of the Draker support team with the AlsoEnergy support team
o Please note the new phone number: 866.303.5668 x2

AlsoEnergy is migrating all Draker sites, data, and configurations to the PowerTrack Platform. In addition, Draker customers will have access to the full suite of PowerTrack features and capabilities such as advanced PV modeling and analytics, dashboards, and a wide range of standard queries and reports.

As part of the Draker Continuity Program:

• AlsoEnergy will honor existing orders accepted by Draker as of 7/3/2018 for Draker monitoring and hardware.
• All legacy Draker sites will continue to operate on the Draker platform until AlsoEnergy completes site migration to the AlsoEnergy PowerTrack Platform.
• AlsoEnergy will work with Draker customers to upgrade cellular modems to the latest 4G networks to enhance security and performance as needed.
• AlsoEnergy will work with Campbell Scientific to honor all Campbell Scientific data logger warranties.
• Certain Draker features, such as customer dashboards, DBS4, and the SPT String Optimizer, are subject to additional review. We encourage you to contact AlsoEnergy to discuss in further detail.
• Replacement hardware will be available for purchase through AlsoEnergy.

— Solar Builder magazine

The 2018 International Solar Energy Provisions is ready to order

Solar Energy Provisions

The International Code Council and the Solar Rating and Certification Corporation (ICC-SRCC), in collaboration with the National Fire Protection Association (NFPA), have updated the 2018 International Solar Energy Provisions (ISEP). This publication compiles the solar energy provisions of the 2018 International Codes (I-Codes) and the 2017 National Electrical Code (NEC or NFPA 70) and related ICC-SRCC standards into one comprehensive document on the design, installation and administration of solar thermal and photovoltaic systems. Order a copy right here.

“We are excited to present this tool, the best and most comprehensive publication of its kind on solar thermal and photovoltaic systems,” said ICC-SRCC Vice President of Technical Services Shawn Martin. “As the leading provider of ratings, certifications, codes and standards for renewable energy, we are proud to partner with NFPA to help the solar industry, designers, contractors and administrators better implement safe and resilient solar energy projects.”

The ISEP is available for adoption by interested countries, states and local jurisdictions as their solar energy code, and it mirrors the format of the I-Codes, a family of fifteen modern, regularly updated building safety codes used throughout the world. The ISEP contains separate provisions for commercial and residential buildings, and two important solar standards have been included in their entirety: ICC 900/SRCC 300–2015, Solar Thermal System Standard, and ICC 901/SRCC 100–2015, Solar Thermal Collector Standard. Additional resources, such as the Checklist and Submittal Requirements for Expedited Permitting of Solar Photovoltaic Systems and the U.S. Department of Energy Solar Site Access, are also included.

— Solar Builder magazine

ForeFront Power to deploy solar, AI-powered energy storage for collection of California schools

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An artificial intelligence-powered energy storage company, Stem Inc., is working with C&I solar developer ForeFront Power to develop solar+storage energy systems for schools and municipalities throughout California. ForeFront Power and Stem were selected as the best renewable energy solutions provider by the School Project for Utility Rate Reduction (SPURR), a California-based joint powers authority that aggregates the buying power of over 240 member schools, colleges, and other public agencies.

Over 20 public agencies have used SPURR’s Renewable Energy Aggregated Procurement Program to secure preferential pricing and terms for solar and storage solutions with less sourcing expense and effort. ForeFront Power’s solar solutions and financing, paired with Stem’s energy storage, enable public schools and agencies to reduce substantial energy expenses, hedge rising utility costs, and conserve bond funds for other needs, with no need for capital outlay or bond money.

Stem, Inc. has been developing solar+storage projects since 2013 for public and private non-residential customers, including sites at several California schools and universities.

“Our artificial intelligence and partner-friendly platform allows solar developers to maximize economic returns for the solar customer in the face of dramatically changing solar rates and rules, while also building the capabilities for future grid services revenue,” said John Carrington, CEO of Stem, Inc.

Stem has the largest project finance pool among its peers, now over US $500 million, enabling Stem’s 860 energy storage systems under management across five states and three countries (U.S., Japan, and Canada). Athena, Stem’s cutting-edge AI, is the first of its kind for customer-sited energy storage, performing real-time energy optimization that reduces onsite peak demand and enabling customers to participate via Stem’s networks to access additional services and value streams.

— Solar Builder magazine

When augers, ground screws make economic sense for solar contractors

SunModo solar auger

A small Bobcat 331 being used to drive a 10 ft auger using the technique of advancing upon the auger to vertical as it is driven.

The use of augers and ground screws has been of interest in mounting solar systems for some time, and for the right sized job, they offer smaller solar contractors an opportunity to grow their business.

Ground conditions

For one, with smaller PV systems one may not need to spend money on a soil engineering analysis and the cost to permit the design separately. The typical soil type in an area may be known from experience. Perhaps local experience with other construction such as a home foundation or a water line installation can provide clues to the soil type.

A method used by some contractors is to use a hammer drill and ground rod available from an electric supply store and see how easily the rod can be driven into the earth. If the rod hits solid rock 6 inches below the surface, or if the rod is very hard to drive, this could either disqualify the use of ground driven foundations. In some cases this could lead to using ground screws rather than an augers. Additionally, many counties and states have published maps showing the soil types for many locations. Other sources of data are well sites where there is often a record by the foot of the surface to depths much greater than one would drive a ground driven mount.

Selecting a ground mount

Once a determination has been made as to the type of soil at a site, the installer should select a ground mount to use at a site. If the soil type is not heavily compacted and not rocky, one can consider the use of augers. Most typically, a ground auger driven 7 to 10 ft. will suffice for most 3 and 4 row landscape arrays.

If the ground is compacted, made up of heavy clay, or has small rocks within the first 10 ft., then a ground screw would probably be a better choice. Ground screws offer lower torque when driving them into the soil and are less likely to break in harder ground. However, in soft, loamy soils a ground screw will not provide big pullout values compared to an auger.

If the ground is too rocky, other options such as post and concrete, ballasted arrays, or rock anchors may be a better alternative. Experience with ground arrays will greatly help in the selection of a ground mounting system.

SunModo augers

Auger being driven at Groundwater site with Bobcat 337

Driving ground mounts

Some form of tractor or track machine is required to drive ground driven foundations. These machines are easy to rent and use, and depending on the volume you are doing, worth owning. Small arrays with only 8 or 12 posts are probably not worth the investment, but between that and larger arrays that require a specialized company drive the mounts, there is a sweet spot that makes financial sense.

The machine used will need some form of rotary head such as the small Bobcats used to dig holes for pole buildings and fence posts. Alternately, some farm tractors have a rear mounted rotary driver used for fence posts that may be used.

Most equipment rental yards can supply a small track machine normally used with a hole digging auger. With the hole digging auger removed, an adaptor can be used to mate the drive head to fit augers and ground screws. A 2 inch to hex adaptor that fits the machine can be purchased by the installer if not available from the equipment rental yard with the machine.

Figure 4 – Drive adaptor to convert from hydraulic head on rental machine to 2 inch ground mount.

The amount of torque required to drive a ground mount should not be more than a nominal 3000 pounds. If more torque is required, or if the mounts are breaking, than the wrong mount was selected. If augers break, a ground screw should have been used. If ground screws break, then a non-driven mount should be used.

If occasionally a mount breaks due to an undetected boulder or other issue, a traditional post and concrete mounting should be used. In the case of Groundwater a 50 kW project in Portland Oregon, where over 400 augers were used, 8 anchors broke due to large sporadic rocks and were replaced with 8 post and concrete mounted posts.

Auger and Ground Screw Guidelines

This post is an excerpt of this full guideline from SunModo, which clears up the confusion surrounding the use of augers and ground screws. To view the entire white paper, enter the info below.

Calculations and measurements

There are many resources available covering the use and calculations for commercial construction using augers and ground screws. These include Chance Hubble manuals, and other commercial suppliers of augers. However, there are some general guidelines one can follow summarized below.

Augers have a pitch determined by the blade angle. Our auger is a 10 to 1 auger. Using a 10 to 1 auger, each ft. lb. of torque driving the auger provides approximately 10 times the uplift capability when driven to 10 ft of depth. For example, if an auger is driven with 500 pounds of torque to 10 ft. the pullout will be approximately 5000 pounds. Typically augers are driven much harder, resulting in tested pullup values of 20,000 to 30,000 lbs. Most often, augers driven in reasonable soil values will dramatically exceed the pullout values actually required to resist pullout or overturn of the array.

In the case of ground screws, they are typically applied to more dense soils and solids with rock intermixed. A ground screw should not be used in solid rock.

Ground screws in hard soils have pullout values of 1500 to 5000 pounds at a depth of 5 ft., however this estimate is entirely based upon the soil density. The use of ground screws in soft soils will not provide a satisfactory base for a solar array.

The use of a torque measurement gauge is recommended as an additional check on the drive torque and resulting pullout capability. Some modern machines one can rent or buy have a built-in torque gauge. Additionally, there are devices that can mount between the hydraulic head and the ground mount to measure the torque. However, a careful operator will have some sense of the amount of effort required to drive the ground mounts and in most cases can successfully install and driven ground array without a torque head.

Cliff Schrock is an engineering consultant with SunModo.

— Solar Builder magazine