Future's So Bright ...

we gotta wear shades. The city of Palmdale is stuck between a rock and a hard place. On the one hand, it is home to an enormous airport that has never lived up to its 1968 billing of a destination for supersonic passenger jets. Indeed, Los Angeles World Airports (LAWA) reportedly gave up altogether on commercial operations when United recently canceled the last remaining commercial service to SFO because it had become unprofitable.

Although LA County voters seem to have narrowly rejected Measure B on March 3, it is still possible that the LA City Council may implement its conditions anyway and create a legal obligation to install 400MW of renewable electricity generation capacity in the county. LAWA is therefore proposing that a fraction of the 17,750 acres of land occupied by its Palmdale airport be used for a 100MW solar thermal power plant. For reference, LAX occupies around 3,500-4,500 acres (estimates vary by source).

On the face of it, this is excellent news for high speed rail, which is supposed to run entirely on renewable electricity. At full capacity - which won't be reached until 2030 at the very earliest - the fully built-out HSR network would require around 480MW or, approx. 1% of total installed generating capacity in California today (the vast majority based on fossil fuels).

However, the primary reason for the long detour via Palmdale and the Tehachapis was excellent access to a fully operational Palmdale airport to relieve LAX. Palmdale is the only existing airport in all of Southern California that could easily accommodate an additional long runway. Metrolink and the FlyAway bus evidently aren't fast enough to make it commercial viable, but HSR would take just 27 minutes to LA Union Station - a game changer. Ergo, HSR ought to be a huge shot in the arm for this struggling regional airport as well as maxed-out LAX.

The flip side is that HSR's short travel time also implies the risk of further population growth in the High Desert, already home to hundreds of thousands. Ever more growth would be problematic even if it were of the transit-oriented variety rather than traditional car-centric low-rise sprawl. That's because there is very little natural rainfall in the area, so any new residents would have to be supported at great expense to the state by pumping water up the San Joaquin Valley and uphill to the High Desert. The elevation data tells the story: Tracy ~400ft, downtown LA ~400ft, Palmdale ~2900ft. The High Desert is arguably the wrong place for California to grow in.

So, we now have three issues coming to a head - renewable power generation vs. high speed transportation vs. population growth - simply because LAWA happens to own a patch of temporarily unproductive land. It's not as if solar power plants could not be built anywhere else in the state. Complicating the issue is that LA took the airport land by eminent domain decades ago for the express purpose of commercial aviation, so it's not clear that the legal authority to re-purpose the land even exists at this time. Officials from the city of Palmdale complain they were not even consulted about plans to build a solar thermal power plant. From a practical point of view, the questions are if solar power generation would be temporary and/or have any impact on the resumption of commercial passenger flights a decade from now.

For that, we need to consider what a solar thermal power plant actually looks like. One indication is BrightSource's 400MW Ivanpah plant, located deep in the Mojave desert near I-15 and the Nevada border.



Covering 5 square miles, its ~200,000 heliostat mirrors will be computer-controlled to accurately track the path of the sun during the day and year. The reflected sunlight is concentrated in a small area, heating water (or other working fluid) flowing through pipes there to 550 degC (~1000 degF). The resulting steam is converted to electricity using a regular steam turbine and generator. The water is condensed by forced air convection to achieve closed-loop operation. Another emerging technology uses water-cooled high-temperature photovoltaic semiconductor panels that convert the power of sunlight concentrated 500 times directly into electricity. Either way, concentrated solar power plants are not the the sort of installations you can easily move to an alternate location after just a decade of operations.

In terms of airport operations, the risk inherent in a permitting a nearby solar thermal power plant is blinding glare for the pilots. The mirrors are not perfect reflectors and the boiler tower not a perfect absorber of sunlight. A significant amount of light scatters and could prove a threat to aviation safety. So far, FAA has not taken a position because there has been no formal submission to review. Considering that unhindered airport operations are the very reason for running HSR past Palmdale, I would argue that CHSRA should be treated as a stakeholder in any environmental review of siting a solar thermal power plant so close to the airport.

It's possible that glare turns out to be a non-issue and that a solar power plant and unfettered airport operations could coexist quite happily. My point is that no-one has actually verified that to date, so this potential problem should be nipped in the bud before too much effort is wasted on trying to secure ROW and viable tunneling solution for the planned HSR route. If a solar power plant is built and it permanently restricts commercial aviation at Palmdale airport, there's a good case for switching the HSR route to the I-5 Grapevine, cutting 12 minutes off the SF-LA line haul time. Those time savings might be sorely needed if CHSRA's preferred route through Pacheco Pass in Northern California proves impossible to implement for any reason.

The solar plant idea for Palmdale proves that once again, co-ordinated inter-agency planning appears to be in very short supply in the state of California.