Senator Harry Reid - first Hybrid Solar-Geothermal Power Plant - Las Vegas National Clean Energy Sum

Re: Senator Harry Reid - first Hybrid Solar-Geothermal Power Plant - Las Vegas National Clean Energy

This is someting that makes a lot of sense. Except for the heating element, a CSP plant and an NG plant are basically the same thing. Storage of heat in molten salts is fairly inexpensive and very efficient so why not combine more and more power plants in the SW? Simply adding collectors to an existing plant (where feasible obviously) seems like it would be a good way to go. Plow the collected heat into storage and then use it however makes the most sense. Coal plants can't spin up like NG plants can, so perhaps it's not so useful there. do not know. Nukes would be in the same situation I would think.

 

Re: Senator Harry Reid - first Hybrid Solar-Geothermal Power Plant - Las Vegas National Clean Energy

I don't really understand the synergy, other than the synergy of Reid, a powerfull politician to get energy dollars to his state.

PV + Geothermal both may be good to add to the grid, but you don't get any extra energy or better timing than separate plants. Geo may be able to preheat CSP, but I don't quite understand any advantage in this versus CC natural gas.

Tripp, there is a large synergy here. The NG turbines can fire before the solar comes on line. This does make the gas less efficient, but the solar more efficient. It allows you to use more of the sun. With the quick turn on and off of CC gas, turbines can quickly fire up when clouds reduce solar intensity.

One of the justifications of solar is it is timed more for peak demand. Adding CSP means extending the thermal part of the plant. I don't think salt will have much impact until solar is much more widespead.

CSP can help coal, but not the really old inefficient plants. Adding it to CC gas is cheaper. Nukes don't really have any good way to hook up.

 

Re: Senator Harry Reid - first Hybrid Solar-Geothermal Power Plant - Las Vegas National Clean Energy

Chu's smarts probably cancels out Reid's meanderings. Nevada is a good site for solar. It makes great sense when you look at the legal limitations of power plants....they are required to generate X amount of Megawatts with XX% availability. Follow that up with the need to do it while generating very low cost electricity with those numbers and the POSSIBLE synergy is clear. The conventional part provides the reliability and full capacity when needed while the solar part provides the lowest fuel cost when the sun is available. The limitation with other plants has been that coal and nuclear plants are very challenging to make dynamic to handle the solar cycles, passing clouds, and rainy days. Natural Gas Turbines are better, but still not designed from the bottom up to be very dynamic. Geothermal is probably great....if engineered right.

 

Re: Senator Harry Reid - first Hybrid Solar-Geothermal Power Plant - Las Vegas National Clean Energy

Nevada is probably good for solar. I just don't see how PV goes with geothermal other than they both are green. In Nevada solar probably corresponds with peak demand, but geothermal doesn't ebb and flow to provide more of a demand following curve. Wind plus solar makes sense as wind is cheaper and solar fills in more for higher demand air conditioning. This only works in places with the proper grid in place and good sources of solar and wind.

CSP solves many of these problems, but must be built at a huge scale. Rainy days don't matter as much in the southwest as typically air conditioning demand goes down so not as much electricity is needed. Coal does not play well with sun or wind though, so as we add more renewables the amount of coal needs to go down, not that that is a bad thing.

Newer CC quick cycling gas turbines combined with steam turbines can quickly and efficiently fill in demand. FPL has retrofited or is in the process of a CSP solar feeding into the steam turbine of a CC gas plant. That seems to have the best synergies, but still uses fossil fuel combined with the renewable. I can see biogas/CSP being great in the few locations that can support it. Geothermal holds great promise, but here it is more economic for HVAC than electricity. Other places should have better geothermal electricity, it just doesn't seem to fit the combination with PV.

 

Re: Senator Harry Reid - first Hybrid Solar-Geothermal Power Plant - Las Vegas National Clean Energy

The engineering advantage of geothermal is that is can be dynamically regulated. Basically, you can throttle the steam up and down quite fast to the geothermal turbines based on solar PV contribution for a total plant sustained electric output. No real cost penalty results. The heat in the earth is not affected by these dynamics whereas a Many MW nuclear or coal plant cannot be dynamically changed at all. Those plants are usually designed to have two operating conditions; 0% and 100%. My point has nothing to do with each being "green", but just with being two different technologies where the advantages complement each other.

Now the number of places with good solar and good geothermal is rather limited, but where it does exist it may provide the best power (and environmental) bang for the buck. Time will tell.

For a few decades, having solar operating as peaking plants is the most cost effect plant. But the next generation needs very significant storage technologies. My present favorite would be very, very efficient H20 to Hydrogen electrolysis with Hydrogen storage and export. Besides being a solar power plant, it would also be a fuel plant. This would incentivize running all out when the solar conditions permit, regardless of electric demand. However, what the market picks may be quite different than my favorite.

There are so many factors that go into the cost of a kWh. PV can be quickly regulated and works better in clouds, but cannot reach the present CSP efficiencies. CSP is cyclic, but not very flexible during the solar day. (Those turbines like constant load with constant steam.) The list goes on. Where the best tradeoff occurs is a real involved calculation, since a few percent is the difference between plant success and failure. We will get to see if the calculations for this plants was good enough or not. I can see the PV advantages over CSP when combining with geothermal. I cannot see the outcome vs. all other plant architectures.

 

Re: Senator Harry Reid - first Hybrid Solar-Geothermal Power Plant - Las Vegas National Clean Energy

Not really true - the vast majority of costs of a renewable plant are borne up front. To throttle output without being compensated represents lost revenue. Contrast to a fossil fuel burning plant where throttled output will result in a drastic reduction in operating cost.

For this reason you'll see geothermal plants run as close to 100% as possible just as you see solar/wind doing.

 

Re: Senator Harry Reid - first Hybrid Solar-Geothermal Power Plant - Las Vegas National Clean Energy

keep in mind that geothermal peak and avg are not the same, you can use down time to build up well temperature and reservoir pressure.

 

Re: Senator Harry Reid - first Hybrid Solar-Geothermal Power Plant - Las Vegas National Clean Energy

I will be the first to admit that I'm not an expert on the different limitations of geothermal, so any and all detailed knowledge is welcome. However, there has to be some reason for the hybrid nature of this plant, if not the complementary nature of the two power sources.

 

Re: Senator Harry Reid - first Hybrid Solar-Geothermal Power Plant - Las Vegas National Clean Energy

Nevada belongs to the small number of US states blessed with the abundance of renewable energy resources. When talking about renewable energy in Nevada many would first point finger in solar energy as the renewable energy source with the largest potential because Nevada has in average 270 days of sunshine per year, which translated in numbers means that the Silver state could generate between four and six kilowatt hours of solar power per square meter every day. Nevada is currently one of the nation’s leaders in renewable energy race, and in years to come, if current trends continue, I wouldn’t be surprised if Nevada becomes sole leader of the pack.