WACO TRIBUNE-HERALD COLUMN: How Virtual Power Plants (VPP) Work

In an August 23, 2023 press release, the Public Utilities Commission of Texas (PUCT), announced that two “virtual power plants (VPPs)” were certified to provide electricity to Texas.  Review of the necessity of this initiative, and details of implementation are warranted.     

Power Outage Risk.  The impetus for this program appears to be the fragility of the Texas grid. The danger of electric power outages in Texas was dramatically highlighted during Winter Storm Uri in February 2021. According to www.poweroutage.us, 4.4 million Texans suffered power outages during Uri, including up to 30% of McLennan County customers.  One hundred forty-six Texans died of hypothermia, with power outages a probable contributor to most of these deaths.

     The following year, a winter storm, December 23 to 25, 2022, produced blackouts impacting more than 87,000 Texans, with about 36 deaths nationally.  And during the current brutally hot Texas summer, more than 100,000 Texans reportedly lost power—a glaring risk for heat illness and death. Rolling blackouts were narrowly avoided, including in Bexar County in June. 

Aggregate Distributed Energy Resource (ADER).  To address Texas’ shaky power grid and avoid blackouts, the Public Utility Commission has directed development of pilot programs of Aggregate Distributed Energy Resources.  The term ADER basically refers to using large numbers of very small, scattered, consumer power sites, which add up to a significant amount of electricity.   (These small “distributed” power sources contrast with “utility scale” power, such as the familiar wind farms, solar farms, and natural gas power plants).   The ADERs will be created and operated by the numerous retail electricity providers, such as TXU Energy, HOT Electric Co-op, and Direct Energy.  The individual sites/devices in each ADER must be less than 1MW each and the cumulative power must be at least 100kW.  (As a point of reference, my Tesla home Powerwall battery is 13.5 kWh.)  The Public Utility Commission announced that the first two ADERs in Texas would derive from people with Tesla home batteries, residing in the Houston or Dallas areas.

     The primary sources for consumers to contribute power to the grid are from home batteries, EV batteries, and demand response appliances.      

Battery Storage. Since residences and businesses with photovoltaic systems cannot power their facility when the grid is down (a blackout), the addition of a home battery does allow the system to power its                                                                                                                                                                                                                         building during an outage.  In many cases, the battery is used only during blackout situations, thus considerable power is stored which could be used during times of grid insufficiency.  The result is termed a virtual powerplant (VPP), because new power is contributed to the grid, without a new, visible “plant.”  Consumers are reimbursed for the power they provide, as they improve grid reliability.  Some common home batteries include the Tesla Powerwall (13.5kWh), Generac PWRcell (9.0kWh), and Panasonic Evervolt (11.4kWh).

Electric Vehicle (EV) Chargers.  Unlike common unidirectional chargers that charge from the grid to the EV, bidirectional chargers also allow power to flow from the EV battery to the grid.  Since EV batteries may be very large, 100kWh or more, they can provide an enormous source of power that can assist the grid.  The German EcoG and Wallbox Quasar are bidirectional chargers currently available.  Reportedly, the F-150 Lightning, Nissan Leaf, Hyundai Ioniq5, and Kia EV6 are compatible with bidirectional charging.  However, this technology requires synchrony between EV, charger, and grid, and is not yet operational in Texas to my knowledge.  The PUC press release suggests pilot programs are developing this source of power for the grid as well.    

Demand Response Appliances.  These communicative water heaters, smart thermostats, and HVAC systems allow utilities to lower the device’s electricity use during times of peak demand, thus helping to stabilize the grid.  Home comfort will be minimally impacted, but the decreased consumption by thousands of devices may significantly improve grid resilience. Rheem, for example, manufactures electric water heaters that are demand response -ready. Further, by acting on the consumption side of electricity balance, GHG emissions are lowered—because the cleanest power is the power that is not used.

Backup Generators.  Although this modality is mentioned in the press release, these devices burn fossil fuels, produce GHGs, and are not an acceptable power source, in my view.

Status.  The Public Utility Commission of Texas announced that there are currently eight pilot ADER projects, totaling 7.2mW, and that two of these are in full operation, both Tesla Powerwall virtual power plants, in the Houston and Dallas areas.  Since the State of Texas has its own isolated grid, the formation of these VPPs may have increased the reliability of the grid for Wacoans.   As the pilot programs spread to smaller cities, Waco citizens may have the opportunity to participate, if they have rooftop solar with a Tesla home battery.  Purchasing an EV with bidirectional charging capability may also provide eligibility to participate in selling EV battery power to the grid in the future.

     By installing rooftop solar with battery storage, and transitioning to an EV, one powerfully combats the climate crisis.  In addition, with this announcement by the Public Utility Commission, one may also contribute to improving the reliability and resilience of the Texas power grid.      

 

Alan D. Northcutt, M.D.

August 29, 2023

Alan D. Northcutt is a retired Waco physician and Director of the grassroots climate action and education group, Waco  Friends of the Climate.  For free “Climate Crisis is Here” yard signs, email anorthc@aol.com.

 

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