Great question. It is easier to rely on existing transmission at Intermountain than it is to build a gas turbine in LA (along with whatever infra is needed to provide a reliable supply of fossil gas to the generator site). You can even add batteries, solar, wind etc in the future at that site; coal sites are being remediated and turned into battery storage colo in many situations to rely on that existing transmission infra.
Related:
https://en.wikipedia.org/wiki/Path_27 (first two paragraphs are relevant to total transmission capacity to LA from Intermountain, ~2.4GW at ±500kV)
https://en.wikipedia.org/wiki/Los_Angeles_Department_of_Wate...
https://www.eia.gov/todayinenergy/detail.php?id=64604
(consider the fungibility of electricity vs other energy mediums)
The problem is that coal plants are sprinkled with a whole bunch of radioactive fly ash, and normal radiation level for a coal plant would violate the hell out of regulations for a nuclear plant.
New nuke power is something like 5x more expensive than wind or solar — which buys a lot of storage. Existing nuke power is ~about the same cost as renewables so it’s obvious we should keep them running but the case for building new ones is really hard to make.
This is a giant issue with nuclear as you're going to be financing it for decades while solar/natural gas will be producing in a year or two.
Wikipedia says LADWP operates 4 natural gas power plants within city limits, so they do both. It might be hard to find a site for a new generator, and the Intermountain site had additional coal generators planned but not built; building a natural gas generator there makes a lot of sense.
Yes, in general, and especially if (as is the case here) the electrical transmission infrastructure is already in place and you are just switching powerplants at the generating end (its a whole lot cheaper to build nothing than gas supply infrastructure.) But also:
> or is it just more politically convenient to pollute Utah instead of LA?
Its both more politically convenient and less of an adverse impact on human life to pollute farther from dense population centers, yes.
I'd guess that a new coal powered power plant is close to the most impossible thing imaginable to try to build in California.
California Air Emission Regulatory which is already on the books cannot comply with the plants so it makes sense that they are being built outside the state.
Natural Gas has the benefit of being simple to start up and shut down the needed turbines, compressor, exchanger, 1st and secondary loops based on demand. There's still some pollution, but compared to coal the pollution is a few percent in comparison (afaik). It burns more cleanly. Newer plants usually use the most efficient equipment at that time (within the tradeoffs chosen) so costs are often less (though poor material choices may offset this when corruption/fraud is found).
I can’t find any support for your claim that natural gas is “a few percent” of the “pollution” of natural gas.
In GHG terms natural gas is still a fossil fuel that emits CO2. Web searches suggest the number is somewhere between 50% less GHG emissions to a few percent more GHG emissions for natural gas vs coal. This is because natural gas has the additional issue of widespread fugitive emissions across the supply chain which emit methane, an even more potent GHG which itself breaks down to CO2.
As with everything it’s complicated but it’s simply unbelievable that a natural gas plant is anywhere near a 90% improvement over a coal plant which is my arbitrarily generous standard for “a few percent”.
Ultimately there’s just no good way to burn fossil fuels.
I’m not sure what California Air Emission Regulatory is. Do you mean CARB?
Any potential engineer watches this as part of their assignments in Intro to Engineering. Lecture 12 iirc.
They referenced a study showing Natural gas power plants emit 0.2% Sulfur Dioxide, 7% NOx, 60% of CO2 compared to coal power plants, and the study only compared single cycle plants, where most are combined cycle that further lower pollution per kWH metrics.
The CO2 in most combined cycle plants is captured as a valuable feedstock for other industrial uses, or sale.
> I'm not sure what California Air Emission Regulatory is.
Its a generalization for the state of Regulatory in California with regards to air standards.
Specifically, I'm referencing the untenable and ever growing sprawl of ad-hoc legislation that is driving the last two refinery's (Chevron) out of California, as well as the bans on any use of certain chemicals like natural gas.
Last I checked there were at least 6-10 partially overlapping AB/SBs that have been passed and are awaiting implementation deadlines. The cost to do anything as a direct result of runaway regulatory is part of why California is having so many problems. The legislature's actions show they don't want people to be able to do business for certain things within California.
As someone who trained in chemical engineering in the 2000's, we never really discussed the fact that reactor waste streams were pollution, just another effluent to put somewhere. I'm pointing this out since I don't think that the relative performance profiles of petrochemical plants is going to be common knowledge.
> Specifically, I'm referencing the untenable and ever growing sprawl of ad-hoc legislation that is driving the last two refinery's (Chevron) out of California, as well as the bans on any use of certain chemicals like natural gas.
There are more than two remaining refineries in California. According to this there are 15 active in the state (with some certainly slated to close). https://www.energy.ca.gov/data-reports/energy-almanac/califo...
I don't disagree that the regulation in California is burdensome, but these refineries seem to have a really poor track record. I live in the bay area and it's a repeating story about excessive flaring or a gas leak from the east bay refineries and that communities should shelter in place. There was even a big fire at Chevron El Segundo this month that took several of their units offline. In the last 5 years that facility has had 46 air quality violations, and in the last 10 years 17 OSHA violations. https://calmatters.org/environment/2025/10/refinery-explosio...
Then let's not forget the Aliso Canyon gas leak in LA in 2015.
> It was widely reported to have been the worst single natural gas leak in U.S. history in terms of its environmental impact. https://en.wikipedia.org/wiki/Aliso_Canyon_gas_leak
I don't see a reason why we should linger on petrochemical technology if we don't have to. This isn't stuff you want in your backyard.
> Key to making that shift has been the Los Angeles Department of Water and Power, which has ordered less electricity from the Utah plant while simultaneously building a natural gas and hydrogen burning power station just across the street from Intermountain.
Does that mean that LA is building a plant in Utah?
Why not build the plant in LA? Is it more efficient to ship electricity instead of gas; or is it just more politically convenient to pollute Utah instead of LA?