How to reduce BoS solar costs

Joyce Laird

Part 2. The large solar manufacturers certainly see the benefits of simplying installation using systems, reports Joyce Laird...

In part 1: When it comes to driving down solar PV system balance of system (BOS) costs, a key focus is on cutting material, shipping and labor expenses. Innovative developments in panel edging and rack-mounting are doing just that...(read more).

Part 2

Many solar manufacturers are partnering with component suppliers that can help deliver fully integrated systems. “How racking-systems, power electronics, and inverters interact with each other more efficiently and how these innovations can reduce grounding, wiring, cabling and installation costs to improve overall performance and lower costs are critical to the future of the solar industry,” says Alan King, General Manager of US Operations for module manufacturer Canadian Solar.

He stresses: “When I talk about lower cost, I don't necessarily mean lower purchase pricing, but overall cost because of better performing products. Lower levelised cost of electricity over the life of the system. I think that is critical.”

The company works closely with companies developing power electronics, he says. “We only work with those that will back their product for the time length we want, which in our case is 25 years,” he says. “We control the integration of products into our panels so we can say to our customer that the panel and all of the integrated electronics are fully backed by Canadian Solar.”

The firm was the first panel manufacturer to integrate the Zep mounting system two years ago. Its NewEdge panel uses the technology to reduce installation cost. Today, other module manufacturers are also integrating the Zep system and branding their easy mount modules under various names. “We continue to work with Zep to refine it,” says King. “We just incorporated it into our newly introduced AC panels for residential and commercial installations.”

Similarly, China's Hanwha Solar also invests in and partners with promising companies it thinks can add value to its solar chain. One such strategic partners is US company tenKsolar. Its OptiMax Wave combines PV modules, light-smart reflectors, inverters and light weight racking into a single integrated system for easy and fast design and installation. The completely integrated system also features parallel wiring, minimal ballast and no roof penetration for reduced overall balance of system cost.

Dr. Chris Eberspacher, CTO, Hanwha Solar One and president Hanwha Solar says the main challenge for all PV is uniform illumination. “These modules go against some of the common assumptions about how a PV panel should be designed. TenK looked at how they could get a better energy output from any common solar module and teamed up with 3M to use a type of high tech optical reflector to reflect more light onto those modules.”

TenK uses a low cost, thick structure where the reflector and the module are fixed relative to each other. This allows the reflector to boost the energy and power output of the module. It has effectively redesigned the way a module is wired and how the cells are connected within the module to incorporate redundancy in parallel connections. This allows the module to work well in a non-uniform enhanced illumination state.

“The next step was to add embedded electronics for DC to DC conversion so an optimised power stream could drive low cost inverters with a fixed DC output,” says Eberspacher. “Basically, when completely configured, it is an advanced spectroscopic reflector which reflects light which is useful for the solar cell, and transmits light which is not useful so that the module doesn't get any warmer than necessary in order to maximise its sunlight to electricity conversion. This streamlines the module structure and the connection to one another so the modules can be more efficient and have a low wind profile… it just fits without any ballast or added weight to flat commercial rooftops.”

Another Chinese company forming such strategic partnerships is Upsolar. Headquartered in Shanghai, the firm has a global reach, including divisions in Europe the USA, Middle East and Africa. While panel manufacturing is its core business, it maintain alliances with providers of distributed power electronics, framing, racking and mounting products so it can offer full turn-key solutions to customers, says the company's CTO Stephane Dufrenne.

“There are many things that can be done to reduce the balance of system cost,” Dufrenne says. The company offers Zep Solar integrated frames with our modules, which reduce both time and cost of installation, and in a bid to further increase system performance, it has formed alliances with DC optimiser and micro-inverters companies.

“Our AC module, or ACM, is a prime example of the innovation we regularly incorporate into our products through strategic partnership with industry leaders like Enphase Energy and Zep Solar. The ACM with a micro-inverter attached into the ZEP frame is a game changer of the whole residential roof-top PV segment,” Dufrenne says. “Building these relationships while maintaining a focus on our R&D capabilities allow us to consistently improve performance and reduce costs at both the module and system levels.”


Back in the US, Daniel Shugar, CEO of Solaria similarly says by making the trackers part of the panels themselves and integrating the electronics, the firm has been able to reduce the entire cost of system. “It brings about lower cost and higher efficiency,” he says. “It costs about $20 each to make and install an aluminum frame on a large solar panel. Aluminum is a commodity so it's impossible to reduce in cost. You buy aluminum by what it sells for on the market. So we figured out how to completely eliminate that frame, which eliminated the first cost of structure.”

He continues: “Also, because frames are quite heavy and wide, it reduces shipping cost. It also eliminates the need for grounding because conductive materials are eliminated. Frames also tend to trap dirt which affects panel performance, So having it frameless also gets more energy out of the panels over the times of the year. It adds up to a lot in savings.”

Solaria solar panels attach with clips that hold securely, he explains. The trackers are designed around the optimal shape of the panel so it all becomes one structural element. According to Shugar this also speeds up installation time because the simple clip has a top down attachment and eliminates all the screws, nuts and bolts of standard installations. Moreover, the clips are only three to four inches in size and only four are used per panel.

“Our technology integrates the lens into the cover glass. It's a very cost effective way to do it and reduces the cost of solar cell material for our buying by 60%. The byproduct of doing that, is that the glass on our panel is thicker than any standard panel,” he says. “That glass strength is a square function of thickness. If the glass is twice as thick, it make it 4 times as strong. With this type of strength, it doesn't need the reinforcement of a frame. The clips work fine and it passes all tests and certifications with flying colors.”

Solaria's horizontal tracker rotates ff160 degrees to enable it to produces a lot more energy and each row operates independently, eliminating the need for any mechanical device in the middle of an array field.

Nor is it necessary to level the land either to get East/West direction for the site. “Our installations can go with the natural terrain. This also reduces construction cost, and eliminates many environmental concerns,” Shugar says.

About: Joyce Laird has an extensive background writing about the electronics industry; semiconductor development, R&D, wafer/foundry/IP and device integration into high density circuit designs.

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Energy infrastructure  •  Photovoltaics (PV)  •  Solar electricity