To deploy the energy storage systems needed to ensure grid reliability as renewable generation grows, operators of the California power system are working to improve their energy storage deployment models to facilitate market participation and increase incentives for storage providers. Pay the fee. The California Independent System Operator is also revising its model to ensure the deployment of large-scale battery storage projects specifically designed to help protect the grid operating at normal frequencies.
The California Independent System Operator's (CAISO) existing model, called the Non-Generating Resource (NGR) model, is primarily used to estimate the ability of large energy storage systems to participate in the wholesale electricity market in order to keep pace with grid operator schedules and dispatch directives .
The improvements aim to do this by better reflecting an energy storage project's ability to discharge -- supplying power to, or charging from, the grid at a given rate.
According to data released by the California Independent System Operator (CAISO), as of June 1, California had the most utility-scale battery storage systems in the U.S., with 3,163MW of installed capacity.
According to the California Independent System Operator (CAISO) and energy storage advocates, the company's non-generating resource (NGR) model, first developed in 2012, has a unique attribute of being able to charge a battery storage system or supply power to the grid. switch easily.
A key issue with the existing modelling parameters is the amount of compensation that the energy storage system owner gets when charging the battery storage system during periods of excess generation and discharging it to the grid when power system demand is high.
The proposed model revision, revised based on stakeholder input, was published on June 30. Key improvements are likely to be incorporated into the non-generating resource (NGR) model, as well as the introduction of a new energy storage resource (ESR) model.
Unlike the established non-generating resource (NGR) model, the energy storage resource (ESR) model is more complex because it reflects the dynamic state of charge of the battery energy storage system, i.e. the amount of charging and discharging and its rate. But the model is still in development.
Another troubling issue for energy storage providers participating in the wholesale market is that under the current non-generating resource (NGR) model, they have no control over the large-scale solar or other renewable power generation projects that go with them. charging method.
The economic viability of energy storage systems associated with renewable energy facilities is largely dependent on compliance with the U.S. federal Investment Tax Credit (ITC). And whether to get a huge tax credit of up to 30% depends on whether the battery storage system is charged with electricity from renewable energy generation facilities. And the electricity in the grid is not entirely 100 percent renewable.
For this reason, power purchase agreements signed by energy storage systems typically prohibit battery storage systems from charging from the grid. In addition, local property tax incentives depend on charging the energy storage system with electricity from 100 percent renewable sources.
Some energy storage operators are threatening to disconnect from the grid to avoid unnecessary charging in order to obtain the U.S. federal investment tax credit (ITC) and contracts, which can affect access to tax credits and the signing of electricity contracts.
Staff at grid operators are also trying to address the reasons why some storage system providers are not following regulatory instructions.
The grid operator requires the energy storage system to supply power to the grid, known as "up"; or to charge with electricity from the grid, known as "down." The California Independent System Operator (CAISO) does this by dispatching signals on a four-second basis, so energy storage projects can quickly help prevent grid frequencies from going out of acceptable ranges due to unexpected changes in demand and generation.
Some energy storage systems that provide these ancillary services are not responding as signaled by the California Independent System Operator (CAISO), but it is unclear whether this is happening with the energy storage system provider or the operator and is being determined by the grid. operator to investigate.
As a result, stakeholders want the California Independent System Operator (CAISO) to investigate the matter more fully before imposing issues it believes may be resolved.
In addition to protecting U.S. federal tax credits for co-located energy storage systems and improving energy storage systems' compliance with regulatory dispatch directives, the California Independent System Operator (CAISO) is currently trying to work out with energy storage owners and developers how to enable Energy storage systems to replace gas-fired power plants that provide power reliability, which are primarily affected by transmission constraints.
This is relevant to utility-scale energy storage systems in large urban centers, often charged with electricity delivered remotely from wind and solar power facilities.
At the heart of the stakeholder debate is whether there is enough transmission capacity to deliver cheap solar power to power a local energy storage system that would replace local gas-fired power plants.
The California Independent System Operator (CAISO) plans to release the final version of its proposed non-generating resource (NGR) enhancements next month.
