Intermittency Of Renewables?… Not So Much

July 21st, 2013 by Zachary Shahan

Below was a great summary (if a bit simplified in parts) comment from one of our readers on one of our posts last week. I thought it deserved a few more eyes. Also, I happened to go back to a roundtable discussion of utility CEOs today that supports the overall “the ‘intermittency’ of renewable energy issue is overhyped” argument. More on that below the reader comment.

Here’s the comment from Victor Provenzano (paragraph formatting and some links added):

To sum up the so-called “intermittency and storage” problem for renewables: Geothermal has no intermittency issues and experiences fewer ephemeral shut downs than coal, nuclear, and natural gas. Solar thermal — with molten salt as its storage medium — can be designed to have no intermittency issues. Offshore wind yields power more or less 24/7 with relatively limited intermittency compared with onshore wind. The two most common sources of renewable electricity, onshore wind and solar photovoltaics, are, of course, complementary: wind turbines (which, in the case of GE, already have built-in storage capacity) yield more power at night, while solar panels yield power during the day; hence, used in tandem, they can provide electricity 24/7 with “intermittency” being experienced only locally at each individual solar installation. The experience in Germany shows that the more wind and solar PV installations one has in the various regions of one’s country, the less the so-called intermittency problem is an issue because electricity is generated at varying wattages in the various locations more or less 24/7 and the actual total daily electric power levels become more and more stable and more and more foreseeable as the number of installations increases nationwide. At that point, the intermittency deficit is more easily and more predictably counterbalanced with reserve power (natural gas and hydro), storage (pumped hydro, compressed air, flywheels, grid storage batteries), and grid power from neighboring nations. The European experience shows that the “intermittency” issue is being widely and very inaccurately exaggerated by America’s energy specialists. What is more, if one has a mix of renewable energy sources online that includes the non-intermittent forms of renewable energy (hydro, geothermal, and solar thermal with molten salt), the far less intermittent sources (offshore wind), and the complementary locally “intermittent” sources (solar PV and onshore wind with its own built-in storage capacity), then the limited remaining “intermittency problem” can be far more easily overcome.

Well summarized.

In a utility company CEO roundtable at Solar Power International 2011 (video here), the General Manager of Austin Energy through up the same sort of anti-solar lob that the commenter above was addressing. What was great to see was that a couple of other utility company CEOs stood up very strongly to the (intentional or unintentional) propaganda and explained why integrating renewable energy into the grid was not an issue. (To watch the responses quoted below, jump to 1:25:29 in the video.)





Doyle Beneby, President & CEO of CPS Energy, backed him up. “Yeah, I would agree with Armando, I don’t worry about that at all…. Generally, if you’ve got automated meters, if you’ve got the means for a home area network, I think you can easily reduce demand to follow — I call it load-following — for solar. What we found, also, is that there are a very discreet set of customers out there who would volunteer to have their load reduced to follow the drop in output for solar…. So I think that’s a big opportunity out (there) for us. I really think concerns about the grid, so to speak, and even to a degree intermittency, should not at all impede the progress of solar.”

Robert Powers, President of AEP Utilities, also chimed in and said, “I agree with my colleague that near-term there’s no, no issue with grid stability with deploying solar.”

I thought that was all a great, serendipitous addendum to this reader comment. And I’m happy that after about two years I got around to transcribing that. I also transcribed much more back around the time of the conference and roundtable.

By the way, just following that discussion was some more fun discussion around the benefits of solar in protecting against cyber attacks, something two CEOs noted the military was well aware of that and already using solar and microgrids for security reasons. To watch to that section, jump to 1:27:53. And, if you want even more, a very interesting section on what these utility company CEOs and Presidents would wish for if they had one wish that could really help them ramp up solar started at 1:31:05. Or just watch the whole thing….









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