tag:blogger.com,1999:blog-3033288879708780106.post6426029679883811171..comments2023-04-07T05:19:44.951-04:00Comments on Yes Vermont Yankee: Renewables at 90% only IF grid-level storage comes firstMeredith Angwinhttp://www.blogger.com/profile/02737538041807740424noreply@blogger.comBlogger6125tag:blogger.com,1999:blog-3033288879708780106.post-18826321597196142192016-01-22T14:42:03.584-05:002016-01-22T14:42:03.584-05:00Thank you all for your comments.
Engineer-poet: y...Thank you all for your comments.<br /><br />Engineer-poet: your note on the "spikiness" of wind energy was very helpful. I was tying myself in knots trying to say that we could only balance wind-with-wind under quite limited circumstances. You provided a factual record that supported my claim. Thank you.<br /><br />Joris: thank you for the European perspective. This phenomenon exists in America also. The "price" of electricity supposedly goes down, but the "cost" to the consumer somehow goes up.<br /><br /> For example, wind can sell into the grid at a very low price or below zero, because wind also receives Production Tax Credits (PTCs) <i>and</i> wind sells Renewable Energy Credits (RECs) for several cents per kWh. So the grid price is low, but the wind turbines are collecting REC payments. <br /><br />But where are those REC payments coming from? They are coming from utilities who are required by law to buy RECs. Those utilities put the cost of the REC into the bill to the consumer (of course) but meanwhile, on the grid, electricity producers are facing low "prices" for their power. So the price of power goes down (on the grid) and the cost of power goes up (to the consumer)>Meredith Angwinhttps://www.blogger.com/profile/02737538041807740424noreply@blogger.comtag:blogger.com,1999:blog-3033288879708780106.post-1363753711396680032016-01-22T05:29:16.674-05:002016-01-22T05:29:16.674-05:00Great article and topic.
I'd like to weigh in...Great article and topic.<br /><br />I'd like to weigh in.<br /><br />Another way of looking at this problem is to look at the effect of large amounts of wind (or solar) on the price of electricity. This price will plummet whenever wind or solar is oversupplying the market. Prices can then even dip below zero, in which case consumers actually get paid to take the electricity. (this already happens in Germany during periods of high wind/solar, and/or in the weekend when demand is low) <br /><br />While low prices may seem nice, they are not, because it means that electricity producers all lose money, meaning they will go bankrupt sooner or later. Also, no new capacity will be built as long as the broken market conditions persists. This is the situation now in Europe in and around Germany. All producers are loosing money due to the broken electricity market, so all are clamoring for more subsidies. It's not just the wind/solar suppliers anymore, but everybody, including fossil fuel generation.<br /><br />This is what makes claims of some RE advocates that "wind and solar cause electricity prices to decline" so misleading.<br /><br /><br />Put another way: there is a difference between the *price* of electricity (set by the law of supply and demand) and the *cost* of electricity (set by the fixed and variable cost of all the installations and workers generating and distributing the electricity). Adding large amounts of solar or wind pushes down the *price* of electricity, but increases the *cost* of electricity. This situation is unsustainable. Either subsidies keep increasing to cover the increasing difference between price and cost of electricity (German market model), or electricity suppliers go bankrupt and black-outs occur (won't happen, politicians won't allow it for fear of getting lynched by angry mobs).Joris van Dorphttps://www.blogger.com/profile/04716028854724168266noreply@blogger.comtag:blogger.com,1999:blog-3033288879708780106.post-61293534670241618052016-01-21T21:48:32.076-05:002016-01-21T21:48:32.076-05:00If you look at time plots of wind generation in Te...If you look at <a href="http://ergosphere.blogspot.com/2015/10/how-unreliable-is-wind.html" rel="nofollow">time plots of wind generation in Texas</a>, the edges of the curves are very steep. It really does look like the wind is essentially "on or off", where the "on" value is maybe 80% of the peak of the current episode.Engineer-Poethttps://www.blogger.com/profile/06420685176098522332noreply@blogger.comtag:blogger.com,1999:blog-3033288879708780106.post-41580381982539561132016-01-21T10:31:41.357-05:002016-01-21T10:31:41.357-05:00Basically, you can't turn the wind on or off. ...Basically, you can't turn the wind on or off. So backing up wind with more wind would lower the capacity factor of all of the wind. You can think of the extra turbines as sometimes useful, but often "curtailed." If the wind is blowing strongly enough to be a high percentage of the grid...the new turbines cannot run In contrast, we don't "curtail" a gas turbine--we can turn it on when it is helpful, and turn it off when it is not needed. We can use gas when we need it, not just when it is available, like wind.<br /><br />The grid can't take more than 100% of what it needs (unless it has utility-level storage), so when the wind blows well, the new turbines won't be participating. Or if they do participate, the main turbines will have to back off. The financial viability of a wind turbine depends partially on its capacity factor, which is why they put them on ridge lines. So backing up wind with wind is not practical. It adds SOME more wind to the grid but causes ALL the wind to have lower capacity factors. As I said, the new turbines would be waiting around only for particular weather conditions, in order to be useful.Meredith Angwinhttps://www.blogger.com/profile/02737538041807740424noreply@blogger.comtag:blogger.com,1999:blog-3033288879708780106.post-85212791421657776072016-01-21T09:48:27.164-05:002016-01-21T09:48:27.164-05:00Excellent question!
Indeed, the turbines make les...Excellent question!<br /><br />Indeed, the turbines make less power on less windy days. So if you are willing to build more turbines to fill out when the "original" turbines are at half speed, you can add a little more wind to the grid. The new turbines will get very little utilization, however, because the 30% capacity factor for the "original' turbines already includes the times the turbines are going slowly, as well as the times they are going full out. So the extra added turbines would be waiting around for only a limited number of wind conditions. They would have very low capacity factors.<br /><br />I oversimplified in the post, and I said that frequently in the post. In general, you would not build the extra turbines that would have such limited usefulness. <br />Meredith Angwinhttps://www.blogger.com/profile/02737538041807740424noreply@blogger.comtag:blogger.com,1999:blog-3033288879708780106.post-55522651089806167872016-01-21T07:49:50.066-05:002016-01-21T07:49:50.066-05:00Your analysis seems to assume that the wind is eit...Your analysis seems to assume that the wind is either blowing, or not; that a given wind machine is either running at full capacity, or not. Is that really how the turbines work? If the wind is blowing at "half speed" can't the turbine make "half power"? In that case, building say, twice as many turbines would let you produce twice as much power on the "wind at half" days. Anonymousnoreply@blogger.com