The present invention relates generally to quantifying performance of a power generating system, and more specifically to determining a financial product for a power generating system with an uncontrollable input source.
Certain financial products are known or have been proposed for power generating systems, such as supply contracts between a buyer and a seller of electricity. Generally, a financial product is determined based upon a number of parameters that may affect, directly or indirectly, performance of the system. For example, the financial product for a controllable input energy source such as gas and coal may be based on an availability of a turbine driven by steam generated by combustion of those fuels. The financial product may specify, for example, an availability number of about 96% for a gas turbine. Accordingly, if the gas turbine is available for more than 96% of the time, then an appropriate bonus may be awarded to an owner or an operator of a power plant. Similarly, if the gas turbine is available for less than 96% of time then an appropriate penalty may be applied. More recent financial products focus on external parameters such as emissions or noise.
In case of power generation facilities with uncontrollable input energy sources such as, wind, solar energy, wave energy, and so forth, such financial products based only on availability may not be desirable, since the turbines may not operate continuously at rated power. For example, a 1.5 MW turbine may output only 1 MW at a wind speed less than a rated wind speed and may have to be disconnected from a grid if the wind speed is higher than a threshold wind speed. In such cases, variations in power generation capabilities over time, based upon the power curve for the resource (e.g., a curve relating power output to wind speed in the case of a wind turbine) are non-trivial. Such resources thus may be incapable of meeting the stringent requirements of “availability” type financial arrangements of more predictable and controllable resources. Similarly, factors such as lifetime, efficiency, and changes in environmental conditions, that may increase financial risk, need to be considered in determining the financial product that will work best in managing productivity of the resource.
Therefore, it would be desirable to determine a financial product that would address the foregoing issues.
In accordance with one exemplary embodiment of the present invention, a method for quantifying performance of a power generating system is provided. The method includes empirically determining an actual relationship between input of an uncontrollable resource and power output of the power generating system, determining a desired relationship between input of an uncontrollable resource and power output of the power generating system. The method further includes comparing the actual relationship to the desired relationship and determining a plurality of financial parameters for the power generating system based on the comparison.
In accordance with another embodiment of the present invention, a system for evaluating a power generating system is provided. The system includes at least one sensor configured to measure a plurality of input parameters and output power of the power generating system, the input parameters including a parameter representative of an uncontrollable resource. The system further includes a processing circuitry configured to compare an empirically determined actual relationship between input of the uncontrollable resource and power output of the power generating system to a desired relationship therebetween; and to determine a financial parameter based upon the comparison.
In accordance with yet another embodiment of the present invention, a method of monitoring a financial product designed for a power generating system is provided. The method comprises tracking fluctuation in one or more operating parameters of a power generating system that converts and uncontrollable natural resource to power output, the parameters including input of the uncontrollable natural resource; and correcting the financial product based upon the tracking.
In accordance with another embodiment of the present invention, a metering card for a power generating system is provided. The metering card is configured to maintain a database of a bonus or a penalty. The metering card is further configured to calculate a consolidated bonus or penalty based upon the database at a pre-determined interval.
These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
As discussed in detail below, embodiments of the present technique provides a method and a system to quantify performance of a power generating system. The technique also provides a financial product for power generating systems based on current performance. Although the present discussion focuses on wind power generating systems, it is applicable to any power generating system, such as a solar power generating systems, with uncontrollable input energy sources.
Referring now to the drawings,
Wind passing over blades 16 of the wind turbines 12 rotates a turbine rotor 18 about an axis 20 perpendicular to a plane of
Turbine transformers 26 coupled to the power electronics interface step up voltages of the generator 22. The electrical power is then further transmitted to a medium voltage distribution network 28. An electrical feeder 30 collects power from the turbine transformer 26 and transmits it to the medium voltage distribution network 28. In certain embodiments, switching devices (not shown) are generally employed to shut down power generation by one or more of the wind turbine generators during high wind conditions. A power station transformer 32 steps up voltage from the medium voltage distribution network and transmits it to the power grid 14. As will be appreciated by those skilled in the art, other components and circuitry may, of course, be provided for conditioning power produced by the generator, synchronizing phases of power to the grid, controlling power factor, and so forth.
Sensors 36 and 38 control operation of the wind turbine via a wind turbine controller (not shown). In one embodiment, controlling operation of the wind turbine includes starting and stopping of the wind turbine. In yet another embodiment, controlling operation of the wind turbine includes aligning the turbine rotor in the wind direction. Signals from sensors 36, 38, 40, 42 disposed on the meteorological mast and from sensors 45, 46 are transmitted via cables 48 and 50 respectively to a control room 52. One or more output sensors 54 measure output power from each of the turbines 12, which is further transmitted to the control room 52. As will be appreciated by those skilled in the art, such sensors may measure, for example, current and voltage, or may be included in a power monitor (considered for the present purposes as sensor 54) that measures and logs power output directly based upon current and voltage measurements.
Processing circuitry 56 in the control room 52 processes the input signals 58, 60 representing the respective input parameters from the input sensors and the output power signal 62 from the output power sensors. In particular, processing circuitry 56 determines an actual relationship between the input parameters 58, 60 and the output power 62. In one embodiment, this relationship is used to establish a power curve relating the input parameters to output of each generator, a group of generators, or the entire wind farm. The determined relationship is further compared to a desired relationship, such as the ideal, model, and reference or baseline output obtainable at the detected input parameter conditions. In one embodiment, the desired relationship is a relationship between input parameters and output parameters agreed in the contract by a buyer and a seller of the electricity.
The processing circuitry 56 further determines a financial parameter based upon the comparison. In a particular embodiment, the financial parameter includes bonus or a penalty depending upon a difference between the actual relationship and the desired relationship. In another embodiment, the bonus or penalty is attributed to deviations not caused by natural deviations in the input parameters. In yet another embodiment, the financial parameter comprises a warranty or an insurance plan, wherein an upfront fee or a premium based on difference between the actual relationship and the desired relationship is paid by the buyer of electricity. A monetary repayment or a non-monetary commitment such as, for example, to provide equivalent power, may be provided to the buyer based upon the difference. These financial parameters are called as financial products. In one embodiment, the processing circuitry generates a statement or a bill. In an exemplary embodiment, a metering card may be employed with the financial product, wherein the metering card maintains a database of the bonus or penalty and further calculates a consolidated bonus or penalty based upon the database at a pre-determined interval of time.
Power curve measurement is important from a point of view of a seller of electricity generated by the wind turbine. It provides an easy method to calculate the annual energy production of the turbine. The power curve, in turn, is often turbine-specific as well as site-specific. A “cut-in wind speed” 78 is a wind speed at which the wind turbine starts rotating and generates electrical power. In the exemplary power curve 72, the cut-in wind speed is approximately 10 MPH (16 KPH). The wind speed at which wind turbine generates rated power is called as “rated wind speed” represented by reference numeral 80. At this speed power conversion efficiency is generally at a maximum. Above the rated wind speed 80, power output of the wind turbine is maintained at a constant level (rated power output) by a mechanical controller or by an electrical controller. The wind turbine is programmed to shut down at a “cut-out wind speed” 82 to avoid damage to the turbine 12 and the generator 22. In the exemplary power curve 72, the cut-out wind speed 82 is 50 MPH (80 KPH).
A desired relationship between input of an uncontrollable resource parameters and power output of the power generating system is determined in step 114. In a particular embodiment, determining desired relationship includes determining desired power curve for finalizing the contract between the buyer and the seller of the electricity. A number of techniques may be used for such determinations, such as various curve fitting algorithms. It should also be noted that the relationship may be multi-dimensional, depending upon the factors agreed upon the by buyer and seller, and upon those factors or parameters that most affect the production of power. It should also be noted that the power curve (or more generally, the desired relationship) might be established during a commissioning phase of operation of the system, or during normal operation. Moreover, because certain combinations of input parameters may not be encountered as often as others, the relationship may be adjusted or updated as such new combinations of conditions occur.
Once this desired relationship has been established (and agreed upon), during normal operation, the actual relationship is compared to the desired relationship in step 116. In a particular embodiment this comparison includes comparing actual power output of a power generating system with the desired power output and determining whether the actual power exceeds or falls short of the desired power beyond a range. Further; multiple financial parameters for the power generating system are determined based on the comparison in step 118. In one embodiment, determining the financial parameters might include applying a bonus or a penalty depending upon a difference between the actual relationship and the desired relationship. In another embodiment, determining the financial parameters might include determining a monetary payment or an equivalent power depending upon a difference between the actual relationship and the desired relationship. These financial parameters may be part of the agreement or financial product established between the buyer and seller. It should be noted that the present invention also contemplates such financial products that are offered or established by third parties or even by markets that do not directly include the buyer and/or seller of power. Thus, the product may be similar to a hedge contract, insurance contract, supply/requirements contract, and so forth.
The financial product may be corrected based upon such tracking, as indicated in step 134. In an exemplary embodiment, correcting the financial product includes adjusting a bonus or adjusting a penalty. In another embodiment, an amount of power to be provided in case of deficiency is adjusted. In one embodiment, value at risk for the seller of the electricity is adjusted. The term ‘value at risk’ as used herein, is a measure of financial risk for the seller of electricity. In yet another embodiment, an empirically determined actual relationship between input of the uncontrollable natural resource and power output of the power generating system is compared to a desired relationship therebetween as discussed above. In one exemplary embodiment, the empirically determined actual relationship between input of the uncontrollable natural resource and power output of the power generating system is determined during actual operation of the system, as also discussed above.
While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.