Windpower: Can MISO Get Too Much of a Good Thing? VITO Perspective Karl Kohlrus P.E. City Water, Light & Power (CWLP) Springfield, IL 4 th Annual

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1 Windpower: Can MISO Get Too Much of a Good Thing? VITO Perspective Karl Kohlrus P.E. City Water, Light & Power (CWLP) Springfield, IL 4 th Annual MISO Stakeholders Meeting Renewable Resources Integration Challenges April 16, 2008

2 This presentation does not necessarily reflect the views of each of the individual Vertically Integrated Transmission Owners. 2

3 The Vertically Integrated Transmission Owners (VITOs) support the development of renewable resources, including wind, within MISO. CWLP, in particular, has already purchased 120 MW of wind starting in 2008, equivalent to about 25% of its peak demand. However, this development must be done in a manner that recognizes the challenges of integrating large amounts of variable output generation into the system. 3

4 1. The appropriate level of renewable resource integration in the region: a) 5 years b) 10 years or c) 20 years MISO should perform RTO-wide studies to examine the consequences of various levels of renewable resource development considering the following factors: Operational considerations such as generation dispatch issues State renewable mandates Necessary transmission infrastructure Constructing new EHV facilities These studies will allow policy makers and other stakeholders to make informed decisions related to the appropriate level of renewable resources. 4

5 2. Challenges for renewable resource integration relative to: a) Transmission Renewable resources can be sited and built much more quickly than transmission facilities. This could lead to congestion and curtailments of renewable production until the necessary transmission facilities are in place. MISO should provide information to stakeholders on the best locations on its transmission system to site generation including wind. Although these locations may not have the best wind conditions, they are locations where wind generation could be interconnected in a more timely manner. 5

6 2. Challenges for renewable resource integration relative to: a) Transmission Because it is difficult to predict very far into the future when wind farms will be producing, scheduling maintenance on transmission facilities used for wind outlet may be challenging. Transmission outages could lead to congestion and/or curtailment of wind generation. However, the existence of additional transmission facilities, built primarily to deliver wind power, could provide opportunities for maintenance at non-traditional times (summer or winter). 6

7 2. Challenges for renewable resource integration relative to: b) Unit commitment and dispatch Installing more wind generation than the system can accommodate could lead to generation curtailments, negative LMPs, and uneconomic use of both wind and conventional resources. Too much variable output generation could put a strain on regulation available from conventional resources even with the ASM in place. Conventional generation resources are needed to back up and provide regulation for wind farms. Allowing wind to be a dispatched down by throttling back and operating at less than full capability could add operating flexibility to the system. 7

8 2. Challenges for renewable resource integration relative to: b) Unit commitment and dispatch The problem of having enough regulating reserves from conventional fossil units to handle the variability of a large amount of variable output wind generation may be solved when MISO begins operating as a single balancing authority under the Ancillary Services Market. The diversity of wind farms spread over a large geographic area connected to the same large Balancing Authority causes the wind variability to be largely cancelled out. Still, there are operational concerns with large amounts of wind. For example, in Texas on February 26 th wind output went from 1700 MW to 300 MW during a 4000 MW load pickup. 8

9 2. Challenges for renewable resource integration relative to: b) Unit commitment and dispatch Because wind generation is not coincident with load, there is a maximum amount of wind generation that can be integrated into the system to maintain reliability during all periods of the year. Environmental equipment on fossil plants such as Selective Catalytic Reduction devices (SCRs) have significantly raised the minimum generation levels of these plants given them a smaller operating range and less room to regulate. 9

10 LOAD, GENERATION AND WIND CURVES Based on CWLP 8/1/2007 Actual Data with Nameplate Wind Equal to 25% of Annual Peak Load Combustion turbines needed here. MEGAWATTS Wind Curtailments needed here Wind SteamMin SteamMax Load Load - Wind HOUR 10

11 2. Challenges for renewable resource integration relative to: b) Unit commitment and dispatch We should not only use traditional approaches to address wind dispatch. Coupling wind with load management, energy storage, and/or wind curtailment strategies should be investigated. Before MISO designs a transmission system to deliver wind generation to load, MISO needs to answer the threshold question of how much connected wind capacity the MISO system can accommodate. MISO should require that wind generators provide forecasts to MISO for both the day ahead and real-time markets. Installing too much wind could result in reliability problems, negative LMPs, and increased curtailments of wind. Increased curtailments of wind could have a detrimental effect on wind farm economics and cause RPS goals to be missed. 11

12 2. Challenges for renewable resource integration relative to: c) Public Policy Renewable Portfolio Standards ( RPS ) and goals have been passed without detailed regional studies showing the impacts of large amounts of variable output generation on the system. MISO needs to perform wind integration studies to determine the maximum of wind the MISO system can accommodate as a percentage of peak load so policymakers can be advised about the real-world consequences of RPS goals. 12

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14 2. Challenges for renewable resource integration relative to: c) Public Policy The development of Plug-In Hybrid Electric Vehicles (PHEVs), and shifting other loads to off-peak times, may enable the MISO system to accommodate more wind capacity by increasing minimum loads. 14

15 2. Challenges for renewable resource integration relative to: d) Financial Equity Cost causation principles must be adhered to when allocating the transmission costs associated with renewable generation. If MISO must build more transmission than it needs itself to deliver wind power to the rest of the Eastern Interconnection, then the costs for such transmission must be appropriately borne by those outside of MISO who benefit from such facilities. 15

16 3. The proper role of MISO in the integration process MISO needs to perform the necessary production costing studies to determine the maximum amount of wind that can be accommodated from a MISO centric view. The initial study should incorporate a copper sheet transmission system. Then MISO, with the help of the TOs and other stakeholders, needs to determine the appropriate transmission facilities to accommodate the MISO centric wind and prepare cost estimates of such transmission. MISO should provide this information to policymakers. 16

17 3. The proper role of MISO in the integration process Investigation of where to locate wind should take into account market forces such as the trade off between the best wind locations and locations requiring little incremental transmission to be built. MISO should provide wind developers with more information about where the best sites for wind are located. These may be sites with lesser wind conditions but adequate transmission. The current MISO wind interconnection and deliverability procedures have the potential to lead to operational issues that can lead to curtailments, negative LMPs, and uneconomic use of both wind and conventional resources today. 17

18 3. The proper role of MISO in the integration process MISO identifies constraints for which mitigation is required based on two scenarios: either the wind is dispatched at 100% output with constraints identified based on a 20% Transmission Distribution Factor (TDF) cutoff (Energy Resource (ER) injection constraints) or the wind is dispatched at 20% output with constraints identified based on a 3% TDF cutoff (Network Resource (NR) deliverability constraints). 18

19 3. The proper role of MISO in the integration process This methodology leaves as unresolved any constraints for those conditions in which the wind is dispatched between 20% and 100% of rated capacity for constraints with TDF between 3% and 20%. Because the real time constrained economic dispatch process does not differentiate between NR and ER generation, these unresolved constraints will lead to real time congestion and negative LMP pressure. These in turn can lead to curtailments and/or uneconomic use of the installed resources. 19

20 3. The proper role of MISO in the integration process Much more transmission (91,000 MW) is needed for 20% RPS case in the Joint Coordinated System Plan (JCSP) to deliver wind power through and out of MISO than is needed for MISO alone (48,000 MW). Transmission facilities associated with the JCSP need to be determined with appropriate cost estimates. MISO loads should only be responsible for the transmission system needed for MISO. 20

21 3. The proper role of MISO in the integration process Presently there are only seven 345 kv lines that cross the Mississippi River into Wisconsin and Illinois. There is at most about 10,000 MW of transfer capability across the Mississippi in MISO. The JCSP calls for 91,000 MW in wind in MISO to reach a 20% RPS. This may require about 16 new 765 kv 5000 MW each. 21

22 4. Specific actions the Midwest ISO should (or should not) be taking to enable renewable resources in the region MISO needs to determine the current amount of renewable resources it can accommodate from a generation-load standpoint. It must consider real-world constraints of operating conventional generation and determine how much variable output generation can be accommodated before it performs transmission studies. MISO should perform studies to help inform policy makers on the costs and consequences of RPS standards, and operational impacts associated with implementation of renewable generation. 22

23 4. Specific actions the Midwest ISO should (or should not) be taking to enable renewable resources in the region MISO should provide information to stakeholders on the best locations on its system to site generation from a transmission standpoint. MISO should continue its efforts to streamline the Generation Interconnection Queuing process. The development of an EHV overlay with through and out transmission may allow more wind to be sited in MISO. MISO should provide wind developers information on the best locations on the transmission system to locate additional generation. Once specific areas have been saturated with wind, additional wind may have to be built in less desirable wind areas until new transmission is in place. 23