Originally Posted By: Joshua_Skinner
Originally Posted By: JHZR2
There's a few things working against this though....
While GE claims an LM6000 GT is like 42% thermally efficient, at partial load the efficiency goes down (though not as bad as a single shaft system). The concept of bringing plants up and down quickly when a cloud goes behind the sun make them still very difficult to control. And, if you try to recuperate the GTs then you have a very large mass of metal which is not amenable to dispatching with shutdown in between due to thermal stresses... But without good recuperation or some other bottoming cycle approach, there still are plenty of losses.
The best approach, and one that Ive been working to develop over time, is the GT used as a bottoming cycle for a fuel cell plant. The waste heat and anode taigas from the FC plant (as well as any reformer off gas) can be used by a GT (waste heat via a recuperator and off gasses injected into the combustor). This way the GT doesn't thermal cycle other than variable turbine inlet temps when it is actively fired at a higher load, and that's normal. With developments in turbine barrier coatings and hot section corrosion protection, the longevity can be increased a good bit too. The GT also then supports transient loads with a reasonable time constant (as the FC does not like to respond very quickly), and supplemental storage can be coupled in to the FC's power electronics on its DC link to provide both fast transient ride-through and "hybridization" with renewables. It also fixes issues with "hydrogen", as you reform NG or liquids at the point of use, and we have plenty of infrastructure for these, plus know how to reform NG really well as it is a widely used industrial chemical process.
Distributed plants of this kind with MWh-level grid-dispatched storage (frequency regulation storage systems are being used more and more, so we know how to use and dispatch them) would support renewables penetration a good bit.
Thanks for this information. I do so enjoy knowing how things work.
Clouds going behind the sun aren't nearly the issue as clouds between the sun and solar collectors.
And even that isn't a big deal as individual cloud systems cause much less trouble to the grid than variable winds do. Or so I've been lead to believe based upon the differences in installed wind and PV capacity.
LOL, I read that and had a laugh. I was tired when writing.
Regardless of clouds, weather, wind, etc., the challenge is stochastic sources and loads which may have patterns but still can be variable due to a variety of factors.
I have to wonder if the differences in wind and PV are due to the cost of small scale power electronics, the dumping of PV from China and elsewhere on the market, and the way things are subsidized.
I think every roof should have a PV panel or a bunch, but Im not a fan of how the companies trying to sell them for net zero bills try to push these obscenely large systems. I think the model T version should be emphasized, which is an enphase type inverter, just inverting single panels, easily connected to a power panel because it just takes a single breaker, and let everyone start offsetting AC and refrigerator type loads during the hottest part of the day.
