Limitations on transmission and energy storage in Texas led to a loss of renewable energy last year.
The U.S. Energy Information Administration (EIA) reported that the Electric Reliability Council of Texas (ERCOT) curtailed 5 percent of its wind generation and 9 percent of its solar generation in 2022.
Power curtailment is a deliberate reduction of production that could otherwise have been produced. It typically happens when supply exceeds demand and wholesale electricity prices drop to zero or even negative. It is a common phenomenon in solar and wind energy, because these technologies have intermittent production cycles, which requires different technical solutions to support them.
Two main constraints in Texas lead to high limits: transmission and lack of energy storage. Solar power plants in Texas are often built in the western part of the state, where land is cheaper and solar radiation is higher. Much of this a huge number of generations is transmitted to the cities of the east and passes through the bottlenecks of the network along the way.
Transfer restrictions can be relaxed in four ways. First, more transmission can be built in, reducing network bottlenecks. However, this task is not cheap. At the moment there are $7.46 billion for future transmission improvement projects which are expected to be operational between 2022 and the end of 2027, according to ERCOT. These costs are passed on to home and business owners in the form of increases in utility bills.
Another strategy for easing restrictions and cutting restrictions is to install energy storage. Storage can “time shift,” or store low-cost, off-peak energy and discharge it during times of high demand. Battery energy storage can provide additional support to power grids to manage demand by means of ancillary services, load, congestion and sustainability services. At the RE+ Conference 2022 in San Antonio, solar and storage developer 8minute Energy shared that 95% of the two-hour battery’s revenue is generated in the first hour of discharge in Texas.
A third way, less talked about in the booming state of Texas, is making more informed choices about where to place projects and how to size them for maximum benefit. Instead of building massive low-cost solar plants that generate discounted value and require billions in transmission upgrades, solar projects can be installed in a distributed manner, bringing them closer to energy demand.
This makes it possible to install the production on the distribution level, which sends electricity over shorter distances and reduces line losses. It also eases congested transmission and creates a more dynamic network. This is especially true when distributed sun is installed with shared energy storage, enabling revenue-generating demand management services and virtual power plants.
As a fourth strategy, during the “surplus” of renewable energy Customers with flexible electricity demand can use more electricity which would otherwise be limited.
In a grid the size of Texas, flexible demand for 15 percent renewable generation could generate $3.3 billion in annual net savings for all consumers, including those with inelastic demand, Michael Hogan’s ESIG report of the Pacific Northwest National Laboratory notes. study.
About 80% of the cost savings that generate annual savings would come from the necessary costs of investing in infrastructure – generation capacity, transmission and distribution equipment.
As the adoption of “inherently flexible loads” such as electric cars and heat pumps increases, the potential for price-sensitive demand increases, according to the report. To avoid unnecessary infrastructure investments and achieve cost savings, ESIG calls for a gradual assessment and incorporation of expected demand flexibility into long-term capacity planning and procurement at both the mass system and distribution levels, among other measures.
The Texas capping problem will likely need to be solved by a combination of all three strategies. The EIA predicts that if no improvements are made to the ERCOT grid, wind curtailment could increase to 15 percent and solar curtailment could increase to 19 percent.
About 64% of wind and solar curtailments in the EIA analysis occurred when energy from large wind and solar resources exceeded the system’s low electricity demand. An increase in demand, such as through battery charging, could potentially reduce these types of restrictions, said the EIA.
Read more about EIA case study on transfer limits on the growth of renewable energy sources in Texas.