Innovations in PV installation technology

Joyce Laird

Part 2: Utility scale installations can cover anything from municipal distributed solar centres to complete plants with acres of solar farms for harvesting the sun's energy. Building the best structures and systems that offer the technology to back them up is critical to this area. Joyce Laird turns her attention to specific installations at the distributed/commercial scale, as well as the utility side of solar PV.

Distributed and utility scale

ABB's solar division (Wickliffe OH) focuses on building full turnkey commercial and utility scale power plants from as low as 1 MW to 20 MW and beyond. This includes pure solar or solar mixed with other renewable energy technologies. ABB chooses its technology solutions based on what works best in any given geographical area. The company acts strictly as an EPC (engineering, procurement and construction) partner.

“Beyond the cost of solar panels themselves the most critical part of the plant is probably the BOS (balance of system),” Rick L Ulam, Business Development Manager at ABB says. “To address Balance of System (BOS), we produce everything needed to take the energy that is produced and connect it efficiently to the grid. If the customer needs a substation, we can provide one in turnkey format.”

Working from the ‘Smart Plant’ position, ABB designs plants that focus on monitoring and fail-safe systems for total reliability. “A typical PV plant might shut down in a storm, while ours will continue to operate because it can compensate for all conditions,” Ulam says. “Our focus is always how to deploy a plant as efficiently as possible. So, once the plant is built, we develop a system design that maximises the actual production level.”

All panel technology will evolve continually, and power must be transmitted to the grid in the most efficient way. “That's where our focus is. Not many have the background ABB has to do this,” Ulam adds.

Handshakes across industries

Handshakes across industries are also helping in this area. Skyline Solar, (Mountain View, CA) is a utility-focused company that is taking a BOS approach to servicing the distributed energy market.

The company manufactures its complete systems from solar panels to ground mounts, using silicon (Si) solar photovoltaic (PV) cells, both standard and high-gain, from the pick of the “best manufacturers”. Tim Keating, Vice President of Marketing says that they have also aligned all their products to fit the manufacturing lines in idle auto machining and metal forming facilities: “We use these facilities to make our mountings, taking advantage of capital equipment already available. This obviously brings down cost.”

The Skyline system incorporates wrap-around mirrors that collect sunlight from a large area and direct it onto a flat plate panel to generate energy. “Our system reduces the amount of solar panels needed and reduces the amount of silicon cost by 90% when compared to a standard flat plate system,” Keating says.

Skyline recently partnered with Cosma International, a division of Magna International a company with 27 basic auto parts manufacturing plants worldwide. “Our reflective rack is a key part of our system and it is made out of stamped metal parts,” Keating says. “We shift a lot of our cost there which means our capital equipment costs are very low.”

Finding a niche

While SolFocus Inc, based in Mountain View, CA, is also building complete systems based on purchased solar cells, its cell technology is very different.

“We use very specialised high-efficiency solar cells. These are the same cells used on satellites,” Nancy Hartsoch, Vice President of Corporate Marketing explains. “They are compound semiconductors; multilayered, germanium based wafers. Those we use are triple junction with multiple layers on top. The actual cell is 1 cm2. This sits at the bottom of the optical rod. Each reflective bowl/parabolic mirror is about 12 inches across and we put 20 of those in a panel.”

While able to concentrate 650 times the worth of protons down to that small solar cell, reaping much higher energy than many other types of PV systems, this technology must always have direct sunlight.

Hartsoch notes, however, that areas with high solar capacity covers about one third of the global market – so it is a very nice niche to be in. In those locations, using dual action trackers, the technology can provide 20-30% more power at 1 MW than many other types of solar panels. The systems are designed for medium to large scale distributed power generation or utility level.

SOLON SE, (Berlin, Germany) is another multi-level company that is involved in both the installation of large solar utility plants and manufacturing modules – both mono- and polycrystalline.

“We have a total worldwide capacity of about 450 MW,” Daniel Alcombright, Regional Vice President, North America, says. “Our complimentary business is solar power plant design, build and installation. In that area we have about 130 MW total installed, operational and commissioned globally, with almost 200 MW on order.”

SOLON has branded their system the Velocity MW system (velocity megawatt system). “Customisation in the utility market is [about] understanding the real demand profile for each customer. A large utility facility is going to have an energy demand profile that reaches a peak between 5pm and 6pm, while a municipal off-taker such as a wastewater processing plant will need a level consumption rate 24/7,” Alcombright says.

To manage the difference, SOLON offers two basic systems: One is a fixed tilt arrangement and the other uses a single axis tracker or SAT. This follows the sun to achieve maximum performance throughout the day.

“We hold down the cost of field by doing sub-assemblies in the factory so they are shipped assembled out to the field. This saves a large amount of time and labour in installation,” Alcombright says.
Commercial and residential

Residential and commercial rooftops was the first market for solar and it continues to expand as prices come down and quality goes up. Akeena Solar (Los Gatos, CA) has been doing residential fixturing since 2001. Company CEO, Barry Cinnamon says that they still believe this is the most efficient way of generating solar power.

“Our goal has always been to make solar easier and safer. Our Andalay™ system is now in the Lowe's home improvement stores in California, and we are selling to integrators in other states. The system is completely self-contained with all the racking, wiring, and the inverters built-in. All you need are the attachment brackets that are optimal for the type of roof and to run an electrical connection to the panels and you're done,” he says.

Along with the system, a monitoring unit is available that is put into a wall and plugs into any computer so users can know how their system is performing. “This is made by Enphase Energy located in Petaluma, CA, the same company that makes the inverters we use,” Cinnamon says.

Cinnamon adds that because the panels are AC power the system is much safer. “You can't have arching. If you turn the power off to the building it completely turns off the panels so there is no dangerous voltage anywhere.”

Focusing on voltage

eIQ Energy is a young company that received their product certification to UL standards by ETL in October 2009. Based in San Jose, CA, the concept of its product is to be able to take an individual rooftop solar module and get it to produce a voltage level that would be acceptable to any inverter.

“It basically takes the voltage that's coming in off of the panel and boosts it up to meet the needs of the inverter,” Michael Lamb, Vice President of Business Development, says. “If the inverter is optimised to run at 320 V, you set your inverter to run at that, and our box will match that voltage.”

The company has two models, a 100-250 W box and a 350 W box to accommodate all types of solar panel arrays. There are no complicated settings, strings, and less termination points. “Because of the integral distributed electronics we also have the ability to gather data from all these points,” Lamb adds.

Sustainable Energy (Calgary, Canada) addresses all types of installations with its inverter technology, but its main focus is on commercial rooftops. Brent Harris, Vice President of Product Development, says that they have just redesigned their product and are building up global manufacturing capacity.

These new power inverters do not rely on series architecture and instead enable “massively parallel” systems. Paralex™ combines Sustainable Energy's Sunergy™ low voltage inverter with thin-film PV or crystalline modules connected in parallel. This optimises the power from each module, reducing the impact of shading, soiling, and other real world factors, without increasing installation and maintenance costs by adding electronics to each module. Using a parallel setup for the panels, if one goes out, the others continue at full power.

“We are packaging systems to roofing and to other installers. We want to give them an easy kit to install. The kit is all based around our inverter. We've been promoting thin-film because we feel they are best for installation, but we are also applicable to crystalline modules. Based on customer demand, it could be for either one. Along with the inverters, we package everything else needed for easy assembly,” Harris says. A key benefit of Sustainable Energy equipment is its safety and low voltage. Harris says that it is the only system on the market that continually performs at under 120 V DC.

About the author
Based in California, Joyce Laird has been writing for a wide range of industrial magazines for over a decade. Her extensive background in the semiconductor industry created a perfect transition to covering developments in photovoltaics.

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Energy infrastructure  •  Photovoltaics (PV)  •  Policy, investment and markets  •  Solar electricity




17 July 2010

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