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LBL Says There Is More To Flexible Demand

With proper tools, load can be shifted, shaped, shed and more

 

Anatomy of the California Duck

Source: California Demand Response Potential Study Phase 3: The Potential for Shift Through 2030, Lawrence Berkeley National Laboratory. Feb 2020

Everybody, it seems, is looking at flexible demand as the best solution to the rising penetration of variable renewable generation, now a part of life in many parts of the world, where more renewables are challenging the grid operators’ ability to maintain system reliability. This newsletter and countless others are full of ideas and proposals on making more customer demand to respond to price signals and other incentives.

Among several noteworthy studies that has come to our attention is one by researchers at the Lawrence Berkeley National Laboratory (LBL) titled California Demand Response Potential Study Phase 3: The Potential for Shift Through 2030. Published in Feb 2020, the study is focused on the critical situation in California with its famous “Duck Curve,” where the belly is getting deeper while the neck is getting sharper as it moves into late evening hours once the solar energy generation is gone.

The study begins with a statement of the problem, or rather four related problems as illustrated in the above visual. While California’s problem is indeed grave, similar challenges face grid operators nearly everywhere, some more pressing than others.

 

Renewable curtailment: Wasted energy

Source: California Demand Response Potential Study Phase 3, LBL, Feb 2020

 

Lots of variable generation, of course, leads to other issues, including renewable curtailment where significant amounts of renewable generation are wasted because they cannot be used, shared with neighboring regions or stored (visual on right).

Not surprisingly, the LBL study wants to know how much flexible demand exists to use some of that extra generation during the sunny mid-day hours and, more important, how much of the evening hour peak demand can be shifted to other times. The 3 key questions are:

  • How big is the Shift resource?
  • Where is the Shift resource and when is it available? And
  • How can we get more Shift?

 

Shape, shift, shed & shimmy

Source: California Demand Response Potential Study Phase 3, LBL, Feb 2020

The authors explore 4 major ways of moving, shaping or shifting demand as illustrated in the visual on left. Each works within a time span from years to seconds – and some overlap during parts of the time.

To address California’s Duck Curve problem, demand shifting within the daily cycles is most useful, hence the focus of the study. As illustrated in the accompanying visuals, shifting demand within a 2-4-hour window can go a long way to alleviate many of the pressing issues.

The latest phase of the LBL study provides estimates of how big the potential “shift” resource is and how much of the flexible demand can be shifted within the daily cycle. LBL researches looked at various behind-the meter (BTM) assets, storage options, by sector, by end-use and across utilities.

Batteries, as everyone knows, are one obvious answer. The LBL team says that at around $150/kWh-yr., BTM batteries become affordable with potential to shift as much as 5 GWh of load, far exceeding all other options. That much shift in demand, they say, could offset the bulk of the 9 GWh average daily curtailment on a typical May in 2019 on CAISO system.

 

Another typical day at CAISO

Source: California Demand Response Potential Study Phase 3, LBL, Feb 2020

With sophisticated tools and using the available and projected data, the LBL team generates a supply curve for shift for 2030 for California identified by end use and economic sector (visual on page 13). Clearly there is scope for shifting load if the proper tools and incentives can be applied.

The main results of the phase 3 research are summarized in the LBL report as follows:

1. Today’s potential Shift resource could eliminate the average daily renewable curtailment encountered recently, at a lower cost than BTM battery storage. In 2020, the resource that is available at or below the battery threshold amounts to 5.3 GWh of Shift resource, primarily provided by industrial process and pumping loads, as well as commercial HVAC. A single dispatch of this entire resource would be enough, in principle, to eliminate much or all the curtailment.

CA shift supply curve for 2030

Source: California Demand Response Potential Study Phase 3, LBL, Feb 2020

2. Today’s readily accessible Shift resource will need augmentation to meet future grid needs. Although we found above that the Shift resource that is less costly than BTM batteries can potentially address average recent curtailment levels, there is a large tightknit-to-day variation in renewable curtailment levels. The most severe curtailment day in spring 2019 saw 39 GWh of curtailed renewable generation on the CAISO grid, which is far more than could be absorbed by a 5.3 GWh Shift resource, even if all of it could be dispatched twice daily. Moreover, our analysis shows a substantial seasonal variation in both the size of the Shift resource and in the need for Shift, with the largest resource available in the summer, when the need is smallest.

3. New loads from electrification are important potential sources of Shift, but their current enablement costs are prohibitive. Our analysis shows that introducing electrified residential space and water heating can both grow the overall Shift resource and significantly reduce the seasonal variation in availability by boosting the wintertime resource. However, the estimated costs to enable these sites with current technology deployment through retrofits may currently be more expensive than investing in similarly sized battery storage.

4. There are numerous pathways to expand the size of the Shift resource and lower its cost.

How can we get more demand shift more quickly and cheaply? One obvious answer is to have more customers on time-of-use (TOU) tariffs and more pilot project to determine how well they work in practice. Not surprisingly the LBL researches are now embarking on the phase 4 of the study with more results expected in late 2021.


The LBL team consists of a large group with veteran DR expert May Ann Piette as the principal investigator. She can be reached at mapiette@lbl.gov. n

https://drrc.lbl.gov/sites/default/files/draft_final_report_stakeholder_...

This article originally appeared in the April 2020 issue of EEnergy Informer, a monthly newsletter edited by Fereidoon Sioshansi who may be reached at fpsioshansi@aol.com

Fereidoon P. Sioshansi, Ph.D.'s picture

Thank Fereidoon P. for the Post!

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Discussions

Matt Chester's picture
Matt Chester on Mar 30, 2020 9:32 pm GMT

Thanks for sharing these compelling developments, Fereidoon. When it comes to flexible demand and flattening the duck curve, I'm always interested in how AI/ML might be able to play a role. Do you have any thoughts on that?

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