By differentiating between a true utility outage (where anti-islanding is necessary) and a grid disturbance (during which the PV system could actually help support grid stability), inverters can stay online during grid disturbances and produce responses to stabilize the grid.

Inverter Innovation and Overall System Cost-reduction

Tucker Ruberti | Advanced Energy

What are some of the factors that have driven widespread PV adoption in the US?

The fact that the total installed cost and lifetime levelized cost of energy (LCOE) of photovoltaics (PV) installations continue to improve has certainly helped spur widespread adoption in the US. These cost reductions are making PV economical to an increasing number of customers, developers and investors, and the industry is continuing to find ways to reduce costs.

Furthermore, new renewable portfolio standards (RPS) and other incentive programs have emerged in states ranging from Texas to Georgia to New York, making solar more widespread and viable throughout the U.S.

Finally, the overall perception of solar as an effective technology continues to grow. The Solar Energy Industries Association reported last year that 92% of voters support solar energy. This shows that as a country, there is more widespread support than some commentators would have you believe.

With increased adoption, what challenges are coming up in terms of integrating solar into the grid?

As commercial and utility-scale solar adoption increases, new PV systems must continue to reduce the costs associated with grid integration. Not only that, these PV systems must actually be an improvement in reliability and performance of the overall grid,as opposed to introducing additional risks or instabilities.  

Can solar play a positive role on the grid? 

Absolutely—International interconnection requirements, emerging domestic standards and technology innovations from PV inverter manufacturers are combining to not only ease the transition of increased solar energy on the grid, but also improve grid reliability and power quality.

What role does the inverter play in reducing the impact of solar on the grid, and putting solar in a position to increase grid reliability? Can you give an example?

In terms of inverter-based solutions, one specific area that comes to mind is fault ride through or FRT, which can enable PV plants to stay connected and support the grid during grid disturbance events. This helps improve grid stability instead of compromising it.

As PV penetration increases, the problem of how PV systems detect and react to grid variations becomes exponentially more important to overall grid stability. More interactive controls are required to ensure inverters disconnect when necessary, but also stay online when levels of utility voltage and frequency drop. PV has an incredible opportunity to add value to the grid at the distribution and transmission levels by providing far more than just MW hrs.  Inverters from the leading technology suppliers can provide a full suite of grid support function from reactive power to voltage and frequency support.

By differentiating between a true utility outage (where anti-islanding is necessary) and a grid disturbance (during which the PV system could actually help support grid stability), inverters can stay online during grid disturbances and produce responses to stabilize the grid.

Low voltage ride through (LVRT) is one example, but Zero and High VRT, as well as frequency ride through, also can help mitigate voltage events, stabilize the grid, and improve energy production. The full suite of FRT capabilities is a crucial technology in managing PV penetration on the grid.

FRT is just one example on how the industry must continue to innovate on all fronts to keep the costs of solar declining, while making solar’s existence on the grid as seamless as possible.

What are some of the latest technological advances in inverter design that have resulted in overall system cost-reduction?

Cost reduction is certainly one of the big challenges facing the inverter space right now. Particularly with the cost of modules plummeting, additional components of the system—such as inverters—have become a focus in price reduction for EPCs looking for a new competitive edge.

One thing we at AE Solar Energy have already been able to do to reduce costs has to do with modifications to manufacturing strategies and building additional manufacturing facilities within emerging solar markets. Additionally, we have taken the core concept of “design for manufacturability”—essentially, designing a product with ease of manufacturing in mind—to design inverter products that are quicker and less costly to produce, without sacrificing performance. We have also been able to achieve lower-cost success through well-maintained partnerships with vendors. These measures have allowed us to offer high performance products at a lower cost, which in turn reduces overall system cost.

The continued challenge of providing higher value at lower cost is something the industry must keep delivering on.

How do you see the solar industry evolving over the next 5-10 years?

PV will become an increasing component of the overall energy generation mix.  Enabling high penetration of PV on the toe grid will be critical to enable continued growth of the PV industry at the commercial and utility scales.  Right now utilities are just moving past the understanding phase of how PV can affect the grip in both positive and negative ways, and we are moving into a collaborative phase where the utilities, regulators, and inverter makers are  working together to implement the solutions and enable very high levels of PV use without costly mitigation requirements.  

Another big issue on the horizon is the expiration of the federal investment tax credit (ITC) at the end of 2016. This will make cost reductions ever more important, as well as creative financing tools. The continued drop in module costs, as well as Balance of System (BoS) and other component innovation will likely act as the catalyst for decreased cost.    PPAs will likely continue to be a strong driver for the industry as a whole, particularly when the ITC expires.

What else does Advanced Energy have in store for us over the next few years?

AE Solar Energy will continue to expand its presence internationally—continuing to build strong agreements with companies in China, India and Japan as the corporation looks to new markets for PV.

One of our efforts currently underway is with SGEG, our Chinese partner. Today, we have jointly developed a low-cost inverter for the Chinese market, which is now undergoing performance testing in our Bend, Oregon R&D facility. Once this product is shipping in China, we will evaluate the potential to modify it for other emerging markets, initially, India, during the second half of 2013.

We also remain excited about the North American market as it continues to be an area of strong growth. We were pleased to open our own manufacturing facility in Ontario, Canada last year, as we see Ontario as a strong, growth-oriented market.

The utility business, where AE Solar Energy currently has a solid presence, is definitely expanding and we intend to continue our efforts to innovate and expand there. We have solid relationships with a number of strong players—developers, EPCs and also the end customer, the utility.  We believe the utility market will be a strong one for us going forward.

Even with its ups and downs with some policy changes, the commercial market is also strong. Thanks to a strong presence in commercial-focused regions, AE Solar Energy will likely be able to capitalize on those new markets as they continue to grow.

 

Tucker Ruberti, Director of Segment Marketing, Advanced Energy, Solar Energy

Tucker Ruberti has worked for Advanced Energy, Solar Energy in Bend, Ore. since 2007 and is currently director of strategic product marketing. He has worked in the energy technology space since 1993, working for a broad range of companies including Westinghouse, General Electric, the New York State Energy Research and Development Authority and IdaTech. Tucker has worked on a variety of technologies throughout his career including solar electric systems, fuel cells, and hybrid electric vehicles.

Tucker received his Bachelor of Science in industrial engineering from Cornell University, and his Master of Science in environmental management and policy from Rensselaer Polytechnic Institute.


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