Where is the Power Going

In this episode, Where is the Power Going? . . .

Have you ever wondered where the electricity generated by a PhotoVoltaic (PV) Solar system goes when the system is shut down? Stay tuned for the answer.

On Thursday, February 16, 2023, about 22 attendees from the Cenergy Power staff attended a carport system project tour of a One MegaWatt-DC (1MW-DC) PV solar array at Long Beach Memorial Hospital, in Long Beach, CA. hosted by Eilroma Sarkis, Cenergy's Project Manager. For many, this was the first time visiting a commercial solar installation. As expected, there were a lot of questions from the guests.

To get an idea of the scale of this project, each carport section spans about 45 feet in width and is 200 feet long. There are five such arrays. The tour lasted about one hour; our host explained every aspect of system construction; module layout, system orientation, electrical components, wiring, inverters, shutdown panel boards, interconnection to the hospitals' main electrical service, system monitoring, electrical grounding, and much more. Click the YouTube link to view a few attendees' photos, reactions, and comments.

However, one nagging question kept coming to my mind: "We are standing under a connected 648.72 kW-DC PV Solar Array that is generating DC Power. The system is turned off. Where is the electricity being generated by the modules going?

After discussions with one of our electrical engineers and studying a few physics videos on YouTube, I was reminded that PV solar modules are passive devices. This means the over 1,224 - 530 Watt PV modules only produce a current (electrical flow) when connected to a load. Translation; A load occurs when Power is requested by lighting in the hospital, air conditioning, possible battery storage, or any other on-demand electricity requirements.

Since this system's inverters were turned off, this is considered an open circuit. The 10-50kW string inverters were not fulfilling the demand for a load. Therefore no power (voltage x current) was generated by the system.

However, another fundamental principle applies, the "Conservation of Energy." During a shutdown, the modules will continue to convert sunlight into DC electricity. The electricity generated by the PV modules will dissipate as heat.

The system will simply "idle" until turned on, then the inverters convert the DC electricity into AC electricity that can be used or stored. It's important to note that even when a PV solar system is turned off, there can still be some residual voltage, which can be dangerous. Therefore, it's necessary to follow proper safety procedures when working on or around a PV solar system, even when it is turned off.

Now you know the rest of the story!

I'm Patrick Ball; thanks for listening. See you in the next episode.

Comments

Practiced Hands: The 50-Year Warranty

What Doc Burch Taught Me About Staying Active. We talk a lot about "life hacks" these days, but most of them don’t have a very long shelf life. Usually, they’re forgotten by the next app update. But back in 1972, I received a piece of advice that came with a 50-year warranty. It’s the reason I’m still on my bike today, still chasing a golf ball around Carlsbad, and still—mostly—in one piece. The Kick That Changed Everything It started with a literal kick in the pants. A kid at school in Cuba, Illinois, was joking around and caught me just right. By the next morning, my lower back was screaming. My mom didn’t reach for the Tylenol; she reached for her car keys. "Let’s go see Doc Burch," she said. "He’ll fix you right up." Harry E. Burch, D.C., was a fixture in Lewistown. He’d graduated from Palmer College in ’59 and had been our family’s go-to for years. He was a man of practiced hands and steady eyes. After a quick exam and an X-ray, the mood in the room s...

Stop Buying Rory’s Ball

⛳️ In this episode, why your Ego is costing you 5 strokes a round. I spent last weekend watching the Pebble Beach Pro-Am from the comfort of my La-Z-Boy recliner. It’s a beautiful spectacle. The cliffs, the ocean, the guys whose swing speeds sound like a fighter jet breaking the sound barrier. And during every commercial break, a very serious voiceover tells me that to play like a pro, I need to buy the ball the pros play. They make a compelling argument. They show slick slow-motion footage of a golf ball compressing against a clubface like a stress ball in a vise grip, then exploding down the fairway. Here is the uncomfortable truth that gravity whispered in my ear somewhere around my 65th birthday: I’m not Rory McIlroy. And if you are reading this, statistically speaking, neither are you. The Physics of the Squish When a pro hits a “Tour-level” ball, they swing upwards of 115+ mph (Rory 123 mph). They possess the violence necessary to squish that incredibly hard little sph...

The Miller Effect

In this episode - The Miller Effect . . . The sun hung high in the sky, casting shadows across the desolate landscape of Huron, California. Dr. Vo, a brilliant yet witty electrical engineer, stood before the main breaker box of a massive 1.4 MW-DC solar array that had confounded everyone who had dared to diagnose its persistent issue. It had been six long months of head-scratching and ten failed attempts by others before the desperate call came into Dr. Vo's office. As the sun's rays bathed the vast array in an orange glow, Dr. Vo stepped up to the Main breaker box, his sharp eyes shaded by his green Cenergy cap. He wore his North Face jacket that billowed in the light breeze, and his presence exuded an air of mystery and intrigue that was as pervasive as the problem at hand. The solar array was a colossal assemblage of panels, wires, and inverters, but the main breaker kept tripping, sending the entire operation into chaos. The workers at the site were on edge, muttering, “We’...

The Art of the Annoying Question

In this episode, why "Cool" is the Enemy of Growth Last night, Lori and I joined our friends (team #1) in a professional kitchen at Sur La Table in Carlsbad, CA., for a "Date Night in Southern Italy." On the menu: Steak Tagliata, Sautéed Shrimp with Fried Capers, and handmade Garganelli. The experience was amazing, delectable food and an exceptional highlight: the Amalfi Lemon Gelato, complemented by the barrage of questions. When I’m with someone like Chef Gaetano, who’s incredibly patient, I tend to ask a lot of questions quickly. “Why use a fork to whisk the eggs and not a whisker?” “What exactly is the chemical transformation of a fried caper?” “If I roll this Garganelli a half-inch wider, does the sauce-to-pasta ratio collapse?” I could see the look on a few other students' faces: Is this guy for real? Just eat the shrimp, Patrick. But here’s the wisdom I’ve gathered after nearly six decades of being the annoying guy in the front row: The quality of your l...

On The Fly

Search This Blog