1. Introduction

Two Quotes:

“The best way to predict the future is to create it.” - Abraham Lincoln

“With continued technology improvements and cost declines, we expect that without incentives, wind is going to be a $0.02 to $0.025 per kilowatt hour product, and solar is going to be a $0.025 to $0.03 per kilowatt hour product early in the next decade. Combining these extremely low costs with a $0.005 to $0.0075 adder for a four-hour storage system will create a nearly firm renewable generation resource that is cheaper than the operating cost of coal, nuclear, and less fuel-efficient oil and gas-fired generation units. We continue to believe that this will be massively disruptive to the nation's generation fleet and create significant opportunities for renewable growth well into the next decade.”

- NextEra CEO James Robo

Lincoln said the first quote well over a century ago, and it is eternally true.

Mr. Robo said the second quote more than a year ago, and he was being too conservative. I posted a paper a few weeks ago (linked below) that reviewed future photovoltaic projects, including those with storage. One of these projects was 8minute Eland Solar & Storage Center (section 2.2): This facility will deliver up to 400MW of clean energy to the grid, with the additional capability of storing up to 300MW/1200 MWh via an integrated BESS (battery energy storage system)… Due to the project’s scale, 8minute is able to provide LADWP with the lowest solar energy prices on record in the U.S.: less than 2 cents per kWh.

https://energycentral.com/c/cp/2020-large-pv-and-pv-storage-update

The Eland project will start operations in 2022, and reach full operational capabilities in 2023.[1]

Clearly the future is renewable power, and the grid needs to deal with renewable variability today. This short post will deal with this challenge, and a few others that grid managers are currently responding to. This response involves modernizing grid components and systems to push beyond traditional boundaries.

2. First

“First do no harm” – Modern Hippocratic Oath[2]

The Hippocratic Oath is an oath of ethics historically taken by physicians. However, the above words could be used for many professions, including engineers (like me), grid managers, and, as recent events have shown, law enforcement officers. I have written frequently on PG&E, and the failure to take this advice seriously almost destroyed them (and still might).

Also climate change is throwing many challenges at grid managers all over the world and these will continue to surprise us. They should pay close attention to climate modeling and be prepared to respond.

The need to mitigate climate change has driven the subject of the next section.

3. Renewable Variability

The primary variable renewables are currently photovoltaics (PV) and wind generation.

The good news is, at least for my state (California), PV projects are adding battery energy storage systems (BESS) with the ability to charge during the “duck curve” peak PV output (late morning to early afternoon) and discharge during summer peak demand (late afternoon into early evening). BESS can also help with short-term variability like that caused by partly cloudy days. Short-term variability can also be predicted several minutes before it occurs using sky-imaging systems. This doesn’t mean that this issue has been totally resolved, but the tools are there to seriously mitigate PV variability.

The bad news is windpower. Wind energy is even more variable than PV, and much less predictable. Ideally, long-term storage is needed to mitigate long-term variability, and this has not been widely deployed. Also, better modeling of short–term variability is required.

I have posted a paper on long-term storage on 6/16, and have linked it below.

https://energycentral.com/c/cp/long-term-storage

See the post linked below for information on modeling windpower.

https://energycentral.com/c/cp/2020-wind-energy-update

There is one mitigating factor for wind variability that has started to come on-line: wider geographic diversity. Weather changes drive windpower’s long-term variability, and wide geographic diversity generally averages out most of the low-wind periods. The western Energy Imbalance Market greatly improves energy trading which averages wind power over the western grid. See the two links below for details.

https://www.energycentral.com/c/iu/caiso-part-6a-%E2%80%93-expansion-update

https://www.energycentral.com/c/pip/california-independent-system-operator-part-6-%E2%80%93-expansion

4. Opportunity/Threat

What utility CEO wouldn’t love to increase energy sales? For several decades, there has been a push from regulators and other governing bodies to reduce energy demand, mainly via conservation measures. But now we have an entirely new market: electric vehicles (EVs). Replacing all of the energy currently used by on-highway hydrocarbon-fueled vehicles with electric energy is certainly a great opportunity, but then there is the threat: EVs will be charged per the owners’ needs, not the utilities preference. The good news is that this will probably be mostly OK.

For commuting vehicle owners that can park in their driveways or garages, most will charge at night. This also applies to fleet owners of vehicles (like e-busses) that mostly run during the day. There will be some daytime-chargers (at work, while traveling, etc.) but these will be a minority. Many facilities will use on-site PV + storage to avoid upgrades to their electric distribution system. However, any steadily increasing EV charging loads should be modeled by simulation software used for long-term grid planning in order to mitigate the resulting impacts to the grid.

The other good news is that these changes will happen over several decades, giving utilities time to understand their impact and define the best way to deal with it. Since the impact from renewables variability will mostly be occurring before EVs, there will probably be opportunities to respond

[1] 8minute press release, “Capital Dynamics and 8minute Solar Energy Partner on Breakthrough 400MWac Eland Solar & Storage Center”, Jan 22, 2020, https://www.8minute.com/2020/01/capital-dynamics-and-8minute-solar-energy-partner-on-breakthrough-400mwac-eland-solar-storage-center/

[2] Original Hippocratic Oath actually said “I will use treatment to help the sick according to my ability and judgment, but never with a view to injury and wrong-doing…”, The “First do no harm” is believed to have been added in the 17th century.