Reach for the sky — inspiring an appreciation for renewable energy (where it started…)
I want to re-publish an old article I wrote for North America Clean Energy in 2015, as it is where we started the journey on building a Solis Inverters brand.
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I received the latest issue of North America Clean Energy (Volume 9 Issue 3) and saw my article in print. I want to share this article here in my blog.
Reach for the sky — inspiring an appreciation for renewable energy
In February 2015, two wind turbines were installed on the Eiffel Tower as part of a high-profile renovation to the monument managed by the Société d’Exploitation de la tour Eiffel. This renewable energy system will offset the annual energy consumption of all commercial activity on the Eiffel Tower’s first floor.
At the heart of the wind turbines are two vital instruments, the controller that converts the ”wild” AC voltage from the turbines to DC voltage and protects the turbines in high winds; and the inverter that converts DC voltage back to AC voltage before feeding to the grid.
The inverter installed at the Eiffel Tower is a sophisticated, transformer-less grid-tied wind string inverter. It has come a long way since the first inverter of this type was certified to G83 standard in UK in 2006. The transformer-less technology has gained popularity due to its high efficiency and light weight in recent years. The installed inverter has ultra-wide input voltage range from 30V- 540V in order to take the variable inputs from the wind. It has the world’s first 40 points programmable, linearly extrapolated power curve design that optimizes the power output for these wind turbines. It uses the current controlled PWM (Pulse Width Modulation) inverter technology. With advanced precision MPPT (Maximum Power Point Tracking) algorithm and high efficiency, the inverter is able to respond very quickly to input voltage change and captures wind energy effectively for maximum power production. Typically operated in harsh environments, the wind inverter has a high standard for quality and reliability.
The solar inverter shares a similar platform with the wind inverter, but with a lesser degree of sophistication considering access to more stable input voltage inputs from solar panels. However, the solar inverter has a much bigger stage on which to perform. Per GTM Research, by the end of 2014, a cumulative total of 18.3GWdc solar PV plants were operating in the U.S.
The transformer-less grid-tied solar string inverter is a main player in the residential solar market where third party financing of solar PV is the predominant business model in the U.S. The large third party ownership (TPO) vendors such as SolarCity, SunRun, and Sungevity pioneered this business model and more followed. TPO vendors own the solar systems and the associated equipment risks, helping their customers enjoy low-cost energy with peace of mind. They have the resources and expertise to perform the bankability study of the inverter, especially on the new entrants into the U.S. market, in terms of the safety, performance, and reliability of the inverter and the financial health of the inverter manufacturer. These companies are also looking for inverter innovations which can give them design flexibility for different roof orientations and pitch, improved installation efficiency, and a lower total installed cost.
In recent years, transformer-less grid-tied solar string inverters have been favored over central inverters in the commercial solar market, driven by falling string inverter cost and technology improvements. This market is predicted to rebound in 2015. Commercial solar installations can run up to several megawatts (MW). A commercial installation using a low power, three-phase string inverter will have higher power production due to string-level optimization, potential lower upfront inverter and BOS costs, lower transportation and installation costs, ease of maintenance, as well as advanced monitoring functions.
Remembering what happened in the solar panel industry, there are some who predict the inverter will become a commodity, but some disagree. As the “green heart” of a renewable energy system, the inverter will not have a fate of becoming a commodity. The Eiffel Tower is structural art on a massive scale. “It is not only the art of the modern engineer, but also the century of Industry and Science in which we are living,” said engineer Gustave Eiffel in 1885. With hundreds of components inside of it, the inverter can be considered the mini electrical artwork of engineers.
The inverter has become more intelligent; “talking” and “interacting” with other solar equipment, smart grid, smart home, financial systems, and people directly. The inverter has enhanced safety responsibilities, such as Arc-Fault Circuit Interrupter (AFCI) and Rapid Shutdown Function. In Hawaii, the inverter functions as a junior grid regulator. The Load Rejection Transient Over Voltage (TrOV) function allows an inverter to protect the solar system and electrical equipment in the building from the damage of dangerous TrOV. The frequency and low voltage ride through (LVRT) function allows an inverter to operate more productively during grid instability due to high solar penetration.
Inverters have become smaller with advanced technology. From the perspective of an owner/operator, smaller inverters reduce the costs involved with product, transportation, storage, and installation. New innovations dramatically expand the reach of solar systems to everyone, those who may have tight budget, who may want to start with a small experiment, or who just want to shave off the peak high rate.
Soon, the image of the inverter will shift away from “ugly” industrial equipment to “elegant” home appliance with beauty of simplicity, blending well with both home and business environments.
Established in 1889, the Eiffel Tower was the tallest man-made structure in the world, inspiring the people to reach for the sky. On its official website, it is written, “The Eiffel Tower has weathered decades to establish itself as a symbol of modernity. Everyone’s commitment to the topic of sustainable development requires new symbols; the Eiffel Tower must play its role and carry the message of sustainable development.” Today, some of those 7 million visitors from around the world, will come away from the Eiffel Tower with a new appreciation for renewable energy. The Eiffel Tower now inspires more people to reach for the sky, to chase sun and harness the wind with green hearts.
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