After the major Texas Blackouts last week, Texans are rightfully questioning the reliability and sources of their power in a search for answers about their devastating loss of electricity and water. There are no new answers as to the root cause of this event since our last post (The Texas Blackout: All You need To Know).

We decided to investigate the planned renewable energy generation buildout within the ERCOT system to determine what sort of growth Texans can expect on this front and how that may impact their power conditions going forward.

The findings were revealing to say the least….Texas is preparing for one of the largest solar energy buildouts in the history of the state, to go alongside its already dominant wind energy capacity. While we will leave the reliability question to be addressed fully in a later post, it is worth carefully considering the natural limitations non-dispatchable renewable energy will face in the State.

The current renewable energy grid limits are not immutable…utility-scale energy storage (which is growing, as discussed below), HVDC interconnections and more active ‘smart grid’ demand management initiatives CAN push the theoretical limit of grid penetration for these non-dispatchable sources, as discussed in more depth by members of the Texas A&M Energy Institute (What Went Wrong With Texas’ Power Failure). However, ERCOT and the Texas Public Utility Commission must augment the huge push for renewables with an equally concerted effort focused on grid reliability – or risk further trouble in the future.

For context, we provide a look at ERCOT’s generation mix over the last year:

ERCOT Texas Generation by Source
ERCOT Generation by Source, by Day (Source: EIA)

Texas relies more on natural gas during the summer when power demand is highest. The seasonal generation mix breaks down as follows (in megawatt-hours or MWh):

Generation of energy in Summer by ERCOT TEXAS

Winter generation for 2020-2021 is reflected below:

Generation of energy in Winter by ERCOT TEXAS

While there is a lot more consistency than you’d perhaps expect, we can tell generation resourcesshift with the season.

For example, wind contributes the more in winter and less in summer. The ERCOT solar generation statistics, while skewed by rapid growth in installations over the last year, reflect higher output during sunnier summer weather.

So what about future ERCOT plans?

Providing significant detail about planned renewable generation ERCOT interconnection queue installations within their data repositories. We examined the data to provide clues as to what sort of projects are on tap – with a focus on future wind, solar and battery projects.

First, we dive into the wind generation data…

From an existing base installed capacity of 28.2 GW as of January 2021, ERCOT expects wind generation capacity will grow 7.9 GW (+28%) to reach 36.1 GW over the course of a year. It’s worth noting that some of these projects may not be built, but the plans are instructive.

ERCOT TEXAS Wind Energy by Year

ERCOT Anticipated Wind Capacity Changes by Month (Forward-looking, Source: ERCOT Grid Info)

  • Total Currently Scheduled Installations: 73 (through Sept. 2023)
  • Average Wind Installation Size: 185 MW
  • Total Scheduled Capacity Additions: 13.5 GW

These are significant additions planned for the Texas grid infrastructure; however wind has become a mature grid resource relative to other, faster growing technologies…

Next, we will have a look at the ERCOT Solar generation infrastructure projection, and this is where things get interesting

Solar generation nameplate capacity is expected to grow from a smaller base of 4.6 GW in January 2021 to 14.6 GW in January 2022, an astounding 10 GW addition translating to a massive 320%(!!) increase year-over-year (assuming all projects in ERCOT interconnection queue get built).

At an average of $1.13/Watt of installed capacity, this equates to a remarkable ~$11.3 billion dollars of planned investment into the Solar infrastructure in Texas over the course of the coming year (Source: NREL, Utility-Scale PV, 100MW, 2018, One-Axis Tracker, NREL Solar Installed System Costs).

ERCOT Texas renewable solar generation energy by year

ERCOT Anticipated Solar Capacity Changes by Month (Forward-looking, Source: ERCOT Grid Info)

  • Total Currently Scheduled Installations: 102 (through Sept. 2023)
  • Average Wind Installation Size: 213 MW
  • Total Scheduled Capacity Additions: 21.7 GW (~6.51 GWe avg)

And finally, we arrive at the anticipated battery additions…

These projects tend to range from 50 to 200 MWe, with many planned for installation at mid-year 2021 in North, West and Central Texas. Many storage projects seem to be near isolated energy sources or major population centers.

ERCOT TEXAS renewable battery energy by year

ERCOT Anticipated Battery Capacity Changes by Month (Forward-looking, Source: ERCOT Grid Info)

Texas appears poised for a large ~1.4 GW expansion in utility-scale storage projects over the course of 2021, but will it be enough to add reliability to a grid with max wintertime demand of > 69 GW? When considered alongside the scale of new wind and solar installations, the new energy storage simply does not stack up.

While Texas is in it’s infancy as a player in the energy storage space, the utility and power generation industries in this state will have to focus an outsized amount of attention on this segment as more non-dispatchable power installations are nearing completion.

Andrew Schaper is a professional engineer and principal of Schaper Energy Consulting.  His practice focuses on advisory in oil and gas, sustainable energy and carbon strategies.

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