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Integrated Balance of System solution: The next solar cost savings frontier

By Phil Winters

As PV modules decline in price, the focus on cost savings increasingly turns to the Balance of Systems (BOS). Though material costs of BOS continue to rise (copper, aluminum, steel, etc), costs savings are derived primarily from the engineered integration of the BOS system which can reduce labor and materials on the job site.

Two recent studies concluded that BOS costs will likely exceed the costs of PV modules in the near term, becoming the highest cost portion of a solar system (this is including the mounting system, which we are including in BOS descriptions). According to GTM research, “…attention from developers and EPCs will increasingly be placed on a project’s balance-of-system (BOS) costs. Historically, innovation in the BOS space has been somewhat limited, given its smaller share of the total system. However, BOS costs will represent more than half of total project costs by 2012, and many BOS players are beginning to integrate their offerings into full-service component packages and positioning for greater share in the market via meaningful economic gains.”

As well, the recently launched US Department of Energy SunShot Initiative “aims to dramatically decrease the total costs of solar energy systems by 75% before the end of the decade.” Much of the focus of this initiative is on BOS and labor savings advancements.

During the last decade we have seen a series of shifts in the PV landscape. In 2002, the solar industry was squarely focused on the modules while the inverter was considered a mysterious box with a limited 3 year warranty that could be sourced from only a handful of suppliers in the market. Slowly the focus changed to the inverter, which now comes with standard 10 and 20 year warranties, and boasts thousands of suppliers globally.

Until recently, nary a thought was given to the BOS, with integrators frequently building their own mounting systems out of strut, stuffing their own combiner boxes and cobbling together their BOS solutions from a series of manufacturers via their local electrical distributor.

Thankfully, the industry has matured and many of these “home-made” solutions have abated over time with suppliers stepping in with high quality, volume manufacturing. This has contributed to the decreasing installed cost of PV. There is, however, much to improve upon where significant BOS cost savings can occur, which many manufacturers are now addressing.


Above: Cooper B-Line’s ARISTA™ Monolithic Racking Systems, a product the company says can help keep overall PV project cost down.

Take for instance, the current state of connecting modules to combiner boxes. Most contractors currently do all this work manually; running PV cable the length of the combiner box to module connection point, cutting and stripping the wires, crimping their contacts, assembling the connectors , attaching ID labels and terminating the string in the combiner box. This will be repeated dozens, hundreds and thousands of times depending on the scale of the project. Did we mention this is generally being done by highly paid electricians?

Like days of old, with homemade mounting systems and combiner boxes, this practice results in more cost, more connection points, more leak paths and definitely more potential quality and safety issues due to human error. On top of this, it is questionable whether testing is conducted on every one of those connection points – i.e. pull, hi-pot and continuity testing – thus further increasing potential human error trouble spots, which can be dangerous down the road, costing significant resources to fix.

Now consider the 21st century alternative: a custom made PV cable assembly that is manufactured for your project in a controlled condition, by highly trained personnel, so that this no longer occurs out in the field in the rain, snow or mud but rather in “clean conditions.” It arrives at the job mapped, labeled, guaranteed and 100 percent certified for performance. This approach reduces material and labor costs, while significantly increasing the quality and certainty of long-term system performance. This solution also replaces a highly laborious and time consuming process with a plug and play solution that drives solar to grid parity. BOS breakthroughs like this are driving the reduction in system costs while driving solar towards grid parity. Companies, with their integrated total BOS solution, are driving innovation and cost reductions across the system to benefit the entire solar industry.

When engineers work across product disciplines, rather than in a single product vacuum, designs can focus on reducing labor and materials across the BOS chain. While pure mounting manufacturers design their mounting solution and provide a quote around this one component of the system, a total BOS approach is to review the electrical design parameters of the project to ensure mounting, cable, cable management and combiners are all designed in one integrated fashion to maximize efficiency and cost savings opportunities on each specific project. A complete BOS engineered solution looks at every angle of the project, ensuring consideration of every component in tandem rather than in a vacuum. This reduces cost while increasing certainty of construction logistics, material costs and performance of PV asset.

Let me give you a real world example: We recently worked on a 10 MW project which had received three quotes from three different companies to provide single component solutions (mounting, combiner boxes and PV cable solutions). Standard solutions at a standard price.Then, we designed from a Total BOS Solutions approach.What we were able to achieve by integrating our design practices across our BOS solutions was a 15 percent reduction in mounting costs and a reduction in pier requirements by 33 percent. By matching our mounting configuration to the string sizing of the system, were able to reduce PV cable costs by 50 percent while reducing the labor on PV cable installation by 70 percent. This is a remarkable achievement on one project and needs to be emulated across the PV industry to achieve cost savings through total BOS engineered solutions.

It is a remarkable and positive change for the PV industry that one company can offer roof and ground mounting solutions, combiners and recombiners, cable management solutions, PV cable harness assemblies, wireless monitoring and grid tie solutions all from one qualified highly bankable vendor. We believe the solution has arrived and many are sure to follow this approach.

As solar continues to step onto the world stage of large scale utility and massively distributed rooftops, the manufacturing community also needs to step up their game to ensure they are integrating BOS solutions which provide better performance, higher long term certainty and reduced costs in materials and labor.

Winters is the Renewable Energy Business Development Manager for Cooper Industries (NYSE: CBE) in Canada. Prior to joining Cooper Industries, Winters launched and led project development and EPC firms serving the Canadian and global solar markets.

Winters is a graduate of both Solar Energy International (1999) and the Ontario Solar Academy (2009), and is currently the Vice President of the Solar and Sustainable Energy Society of Canada.

To contact our solar team, please email mailto:solar@cooperindustries.com”>solar@cooperindustries.com or call 1-905-501-3067

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