The Impacts of Wholesale Market Rules and Policies on Clean Energy Goals

A Primer for Local Governments

Appendix C. Barriers to and Opportunities for Solar in ERCOT

Characteristics

ERCOT covers about 90 percent of the electric load in Texas (Figure C1). The transmission of electricity in ERCOT is not subject to FERC jurisdiction because its transmission system is located entirely within the state of Texas, although it is subject to FERC jurisdiction for questions of reliability. Instead, the Public Utility Commission of Texas (PUCT) has jurisdiction over ERCOT, and PUCT approval is required for all ERCOT rule changes. As a result, FERC initiatives that can provide additional opportunities for solar, such as Order No. 2222, do not apply to ERCOT.

Figure C1 | ERCOT’s Footprint

Source: ERCOT 2021c.

Texas implemented retail choice and restructured the investor-owned utilities in 2002, but public power and cooperative utilities continue to operate as vertically integrated utilities that own or purchase power to serve their retail customers.

Significant amounts of renewable energy, especially wind power, have been developed in Texas, which, as of 2020, ranked highest among the states for total renewable power installations (ACP 2021) and second for solar (SEIA 2021b). Total solar capacity in ERCOT reached 6 GW by the third quarter of 2021, and wind totaled 27.5 GW (ERCOT 2021d). Solar development is likely to continue to accelerate; it represents over 53 percent of the MW in the ERCOT interconnection queue as of February 2022 (ERCOT 2022).

Renewable power development in Texas is not driven by a state requirement. Although the Texas legislature established a Renewable Portfolio Standard in 1999 and increased it in 2005, the state surpassed the standard’s goal of 10,000 MW of renewable energy by 2025 in 2009 (NC Clean Energy Technology Center n.d.). Renewable development since that time has continued to expand because of actions taken by corporations, public power and cooperative utilities, and independent generation owners.

Winter 2021 Outages and Subsequent Actions

Changes to ERCOT market rules are likely to result from the response of the state legislature and the PUCT to the power outages that occurred during the second week of February 2021, when Texas experienced a period of extreme cold temperatures and millions of customers lost power. At the highest level of outages, over 26 GW of thermal generation were on forced outages, and wind generated about 3 GW below what was expected (King et al. 2021). Solar outages were generally below 1 GW (ERCOT 2021e).

These events spurred several pieces of legislation in the state, most notably Senate Bills 2 and 3. The former makes a number of changes to the ERCOT board and requires the PUCT to exercise oversight more frequently and thoroughly. The latter includes requirements aimed at preparing for, preventing, and responding to weather emergencies and power outages, including creating requirements for the weatherization of generation and transmission facilities. It also required the PUCT to modify the design, procurement, and cost allocation of ancillary services for the ERCOT region in a manner consistent with cost-causation principles and on a nondiscriminatory basis (Texas Legislature Online 2021).

After signing these two bills, Governor Greg Abbott asked the PUCT to take a number of actions, including the following, which favor conventional resources over renewable energy (Office of the Texas Governor 2021):

  • Redesigning the market to create incentives that “foster the development and maintenance of adequate and reliable sources of power, like natural gas, coal and nuclear power.”
  • “Allocate reliability costs to generation resources that cannot guarantee their own availability, such as wind or solar power.”
  • Accelerating the development of transmission to connect “dispatchable generation,” which the governor defines as “natural gas, coal, and nuclear power plants.”

The PUCT has since opened several dockets and filed orders pertaining to weatherization and market design, with the latter addressing the governor’s cost allocation proposal, among other items. Several stakeholders filing in the PUCT market redesign docket opposed the assignment of ancillary services costs to renewable energy, with some pointing out that renewable energy providers can self-provide or hedge these services (Jewell 2021) and that many solar developers already have a requirement for the provision of replacement power built into their contracts (Hemmeline 2021). Moreover, there is no evidence that ancillary services costs result from renewable energy (Hemmeline 2021; Stoff 2021), and the allocation of these costs could deter future renewable energy development (Stoff 2021).

On December 16, 2021, the PUCT approved some initial changes to the energy market, including steps to avoid extreme price spikes and to implement new ancillary services, but without assigning those costs to renewables. The PUCT is also pursuing a second phase of actions, including the development of “a load-side reliability mechanism that will serve the purpose of ensuring the supply of dispatchable generation is sufficient to meet system demand” (Haguewood 2021, 4). The creation of such a mechanism for capacity payments has caused some concerns among stakeholders, including renewable energy supporters, that it creates additional costs and discriminates against solar and other resources (SEIA and TSPA 2021).

Transmission

Aside from the potential for the PUCT to create new barriers through the allocation of ancillary services costs, a key to continuing the growth of solar and other renewables in ERCOT is having sufficient transmission.

Transmission within Texas was expanded following the state legislature’s passage of a bill in 2005 requiring the PUCT to designate Competitive Renewable Energy Zones (CREZs), which were areas with high levels of planned wind development and where new transmission would be constructed. The CREZ transmission was completed in 2014 and designed to serve 18.5 GW of wind capacity. Yet because transmission cannot be restricted to a single resource type, the CREZ lines benefit multiple resources within the state (Lasher 2014).

But with greater levels of renewables, more transmission will be needed. To alleviate existing transmission constraints, the PUCT recently approved additional transmission in the Rio Grande Valley (PUCT 2021). ERCOT issues an annual regional transmission plan, produced with stakeholder input, that identifies transmission investments needed to address reliability and economic needs over a six-year horizon. As part of this plan, ERCOT conducts several sensitivity analyses to determine transmission needs under alternative assumptions, including a high renewable penetration scenario (ERCOT 2020c).

ERCOT is also required under state statute to conduct LRTP over both 10- and 15-year planning horizons under multiple scenarios and to report the results to the legislature every other year. The LRTP also serves as a guide to the annual transmission plan. The most recent LRTP included the following findings (ERCOT 2020b):

  • Significant renewable energy growth was included in all scenarios because the projected capital cost of wind and solar generation is expected to be recovered by energy prices.
  • Since wind and solar resources have different diurnal generation patterns, they complement each other.
  • Transmission limitations could reduce the construction of wind and solar generation and could also shift new wind and solar development away from more resource-rich regions to sites closer to major urban demand centers, which, in turn, could reduce the amount of demand that can be served by renewable resources.

Capacity

Although renewable energy supporters are seeking to ensure that any market changes that emerge from the PUCT proceedings described above do not disadvantage renewables, there are currently no MOPR or capacity valuation concerns because ERCOT does not have a capacity market or a reserve margin requirement. Instead, ERCOT uses a scarcity pricing mechanism that causes energy prices to rise when operating reserves fall below a certain level,12 reaching as high as $9,000 per megawatt hour, much greater than levels at other RTOs/ISOs. The theory behind scarcity pricing is that if capacity reserve margins are low, energy prices will spike to high levels and attract investment in new resources, which will continue until increases in capacity lead to lower prices (ERCOT 2020a).

The events of February 2021 showed that there are some limitations to this approach. Prices spiked to extreme levels while customers experienced widespread power outages, and about half of the generation capacity was unavailable. The PUCT approved in late 2021 a reduction of the price cap to $5,000 per megawatt hour.

Decision-Making and Stakeholder Processes

ERCOT’s governance process is transparent and allows for the public to comment on proposals. However, there is not a separate voting sector for environmental interests. The primary committee for decision-making is the Technical Advisory Committee, which makes policy recommendations to the Board of Directors (ERCOT n.d.).

The Technical Advisory Committee comprises representatives from retail providers, generation owners, power marketers, utilities, and consumers (ERCOT 2021b). Each sector has four representatives, each of whom has one vote; the exception is the Consumer Sector, which has six representatives (two representatives for residential, consumer, and industrial consumers; ERCOT 2021a).

Table C1 | Relevant Issues in ERCOT and Implications for Local Governments

Issue

Definition/Brief Explanation

Implications for Local Governments

ERCOT Status

Transmission planning

High build-out of transmission for renewables undertaken under CREZs; LRTP required

Large amount of transmission construction provides greater access to lower-cost renewable resources

More transmission is needed to meet the significant growth of renewable resources in the state

Capacity accreditation and markets

No reliability requirement or capacity market

Not an area of concern at present, depending upon outcome of PUCT actions; creation of a nonrenewable capacity obligation could increase costs

PUCT discussions of a reliability requirement for utilities have created concerns that it may result in greater procurement of nonrenewable resources

Energy and ancillary services markets

ERCOT uses high scarcity pricing to incentivize resource development, but at levels that can be harmful to consumers

High scarcity prices may be more harmful to consumers than useful in providing an incentive for renewable resources

Price cap reduced in light of extreme pricing that occurred in 2021

Stakeholder processes

Open and transparent process with opportunity for public comment

Easier to participate in and have knowledge of ERCOT discussions than in other RTOs

No changes are planned for the ERCOT stakeholder process

Notes: CREZ = Competitive Renewable Energy Zone; ERCOT = Electric Reliability Council of Texas; LRTP = Long-Range Transmission Planning; PUCT = Public Utility Commission of Texas.

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