Brendan Kirby

Using Standard Deviation as a Measure of Increased Operational Reserve Requirement for Wind Power

The variability inherent in wind power production will require increased flexibility in the power system, when a significant amount of load is covered with wind power. Standard deviation (σ) of variability in load and net load (load net of wind) has been used when estimating the effect of wind power on the short term reserves of the power system. This method is straightforward and easy to use when data on wind power and load exist. In this paper, the use of standard deviation as a measure of reserve requirement is studied. The confidence level given by ±3–6 times σ is compared to other means of deriving the extra reserve requirements over different operating time scales. Also taking into account the total variability of load and wind generation and only the unpredicted part of the variability of load and wind is compared. Using an exceedence level can provide an alternative approach to confidence level by standard deviation that provides the same level of risk. The results from US indicate that the number of σ that result in 99% exceedence in load following time scale is between 2.3–2.5 and the number of σ for 99.7% exceedence is 3.4. For regulation time scale the number of σ for 99.7 % exceedence is 5.6. The results from the Nordic countries indicate that the number of σ should be increased by 67–100% if better load predictability is taken into account (combining wind variability with load forecast errors).

Evolution of operating reserve determination in wind power integration studies

The growth of wind power as an electrical power generation resource has produced great benefits with reductions in emissions and the supply of zero cost fuel. It also has created challenges for the operation of power systems arising from the increased variability and uncertainty it has introduced. A number of studies have been performed over the past decade to analyze the operational impacts that can occur at high penetrations of wind. One of the most crucial impacts is the amount of incremental operating reserves required due to the variability and uncertainty of wind generation. This paper describes different assumptions and methods utilized to calculate the amount of different types of reserves carried, and how these methods have evolved as more studies have been performed.

Demand Response Spinning Reserve Demonstration

The Demand Response Spinning Reserve project is a pioneeringdemonstration of how existing utility load-management assets can providean important electricity system reliability resource known as spinningreserve. Using aggregated demand-side resources to provide spinningreserve will give grid operators at the California Independent SystemOperator (CAISO) and Southern California Edison (SCE) a powerful, newtool to improve system reliability, prevent rolling blackouts, and lowersystem operating costs.

Demand Response For Power System Reliability: FAQ

Demand response is the most underutilized power system reliability resource in North America. Technological advances now make it possible to tap this resource to both reduce costs and improve. Misconceptions concerning response capabilities tend to force loads to provide responses that they are less able to provide and often prohibit them from providing the most valuable reliability services. Fortunately this is beginning to change with some ISOs making more extensive use of load response. This report is structured as a series of short questions and answers that address load response capabilities and power system reliability needs. Its objective is to further the use of responsive load as a bulk power system reliability resource in providing the fastest and most valuable ancillary services.

Market Designs for the Primary Frequency Response Ancillary Service—Part I: Motivation and Design

The first part of this two-paper series discusses the motivation of implementing a primary frequency response (PFR) market in restructured pool-based power markets, as well as the market design that would create the right incentives to provide the response reliably. PFR is the immediate, autonomous response of generation and demand to system frequency deviations. It is the critical response required to avoid triggering under- and over- frequency relays or instability that could lead to machine damage, load-shedding, and in the extreme case, blackouts. Currently, in many restructured power systems throughout the world, ancillary services markets have been developed to incent technologies to provide the services to support power system reliability. However, few ancillary services markets include a market explicitly incentivizing the provision of PFR. Historically, PFR was an inherent feature available in conventional generating technologies, and in most systems, more was available than needed. Yet, recent trends in declining frequency response, the introduction of emerging technologies, and market behavior may soon require innovative market designs to incent resources to provide this valuable service.

Calculating Wind Integration Costs: Separating Wind Energy Value from Integration Cost Impacts

Accurately calculating integration costs is important so that wind generation can be fairly compared with alternative generation technologies.

ERCOT Event on February 26, 2008: Lessons Learned

The event analyzed in this paper is of special interest, and was widely reported on in the press, because wind generation played a partial role in the event.

Effective ancillary services market designs on high wind power penetration systems

Ancillary services markets have been developed in many of the restructured power system regions throughout the world. Ancillary services include the services that support the provision of energy to support power system reliability. The ancillary services markets are tied tightly to the design of the energy market and to the physics of the system and therefore careful consideration of power system economics and engineering must be considered in their design. This paper focuses on how the ancillary service market designs are implemented and how they may require changes on systems with greater penetrations of variable renewable energy suppliers, in particular wind power.

Separating and measuring the regulation and load-following ancillary services

Abstract Together, regulation and load-following address the temporal variations in load (and generation that does not accurately follow control signals). The key distinction between load-following and regulation is the time period over which these fluctuations occur. Regulation responds to rapid load fluctuations (on the order of one minute) and load following responds to slower changes (on the order of five to thirty minutes). Load-following is defined as the 30-minute rolling average of system load; regulation is then the difference between actual load for each 30-second interval and the rolling average. Hourly load-following is defined as the difference between the highest and lowest values of the rolling average within the hour. Regulation is defined as the standard deviation of the 120 regulation values for the hour. Finally, the implications of the current block-scheduling conventions on load following and regulation are discussed, as is the need for a new scheduling convention.

Market Designs for the Primary Frequency Response Ancillary Service—Part II: Case Studies

The second part of this two-paper series analyzes the primary frequency response (PFR) market design developed in its companion paper with several case studies. The simulations will show how the scheduling and pricing change depending on whether requirements for PFR are included as well as how the requirements are defined. We first perform simulations on the base case IEEE RTS and show differences in production costs, prices, and amount of PFR when incorporating the PFR constraints. We show how new market designs can affect other linked markets when performing co-optimization. We then test a system with a significant amount of wind power, which does not provide PFR or synchronous inertia, to see how the incorporation of PFR constraints may become more critical on future systems. We then show how pricing can reduce make-whole payments and ensure resources needed for reliability reasons are incentivized. Lastly, we show how resources that improve their capabilities can earn additional profit if the improvement is needed ensuring the incentives can work for innovation in PFR capabilities.