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Frequently Asked Questions

Q:  What is the Power from the Prairie Project?


A:   Power from the Prairie (PftP) is a proposed, nominal 4,000 Megawatt (MW) high voltage direct current (HVDC) electric transmission line.  Its purposes are to facilitate the integration of massive quantities of new renewable energy (wind and solar) into the grid, to reliably and economically enable higher levels of renewable energy than would otherwise be possible, and to support jobs and economic development in the states it touches. See the “About PftP” tab for more details.


Q:  Why is high voltage direct current (HVDC) transmission involved, rather than alternating current (AC)?


A:   Compared to AC lines, HVDC lines:

  • Have lower losses when used over long distances (i.e., they are more efficient).

  • Can be used to interconnect asynchronous AC systems (such as crossing the seam between the Western and Eastern Interconnections of the national grid).

  • Enables the power flow on them to be throttled (compared to AC lines where the electricity flows over the path of least resistance, whatever that may be.).

  • Uses far less right of way land per MW of capacity.


Q:  Who will own the Power from the Prairie project?


A:  That remains to be determined.  Power from the Prairie LLC who is sponsoring the project will not be the owners.  PftP LLC is a source for objective, neutral due diligence on HVDC projects like PftP.  The eventual owners will likely come from private and public power investment; not the government.


Q:  What will the Power from the Prairie project cost?


A:   The PftP transmission line (600 miles) will cost about $3 Billion.  A Gregory County pumped hydro storage project (1200 MW, 25 hours duration), if found to be beneficial in additional to the line, would cost another $3 Billion.  The renewables enabled by PftP would represent about $3.5 Billion investment—some would be existing facilities, but much of them would be new.  The viability of all such investments and how to accomplish the project would be evaluated in the Concept Development Study (CDS).

Q:  What is the purpose of the Power from the Prairie Concept Development Study (CDS)?


 A:  The CDS will join, for the first time, a “coalition of the willing” of diverse utility, transmission developer, renewables developers, environmentalists and others to examine the strategic potential of using interregional high-voltage direct current (HVDC) electric transmission to lower customer electricity costs, achieve higher levels of renewable energy in multiple regions, and lower carbon emissions than could NOT be done otherwise.


       In the absence of a coherent federal energy policy, or initiative by the legacy utility industry, or cooperation between their wholesale electricity markets, the CDS is designed to be “productively disruptive” by showing the way toward a lower carbon future. In the meantime, it will enable utilities' states and corporations to achieve their 100% clean energy goals that cannot be done without such interregional initiatives.


Q:  How can a transmission study do this?


A:  Although the CDS will use the Power from the Prairie and other proposed and exiting HVDC lines as examples, the CDS is not a transmission study.  It is broader than that.  Instead, the CDS is a strategic business and policy initiative to demonstrate a New Way of viewing and operating the electric system for the future.  A New Way that is only enabled by interregional transmission.


       Accordingly, the CDS will not just include technical modeling of the transmission system.  Importantly, it will include considerations for technology, coordination with existing RTO/ISO markets, project organization, and regulatory affairs.  The result will be a repeatable road map for how to do such interregional projects nationwide.  A pathfinder, if you will.


Q:  What is the cost of the CDS?


A:   Total cost is $500k to $600k, to be syndicated among multiple participants.

Q:  Would my organization be expected to contribute staff resources to the CDS?


A:  That is optional.  The CDS will be performed by the PftP Team including its subcontractor, Hitachi ABB Power Grids.  CDS Participants are welcome and encouraged to be actively involved in the CDS Participants’ Review Committee.  They would contribute their staff internal resources to do that.  But a Participant does not have to be actively involved.  The CDS will be done turnkey and the Team would provide its results to the Participants whether they are actively involved or not.


Q:  Who owns the CDS?


A:   Power from the Prairie LLC has invested significant time and expense to bring the PftP project and its CDS to this point.  PftP LLC owns the CDS, and the CDS Participants would be subscribing to it.


       Via the CDS Participation Agreement, the CDS Participants will be provided the perpetual right to use the results of the CDS for their own business purposes.


       Copies of the CDS Participation Agreement, which is the consulting agreement between the CDS Team and the participants, are available for review by request via the Contacts page.

Q:  What is the detailed plan for performing the CDS?


A:  The detailed Statement of Work (SOW) for the CDS is available for review by request via the Contacts page.


Q:  Many utilities may be unfamiliar with high-voltage direct current (HVDC) transmission.  How will the PftP Concept Development Study (CDS) handle this?


A:  The CDS Participants may include a combination of utilities who have HVDC experience and those who do not.  Regardless, the CDS process will engage Subject Matter Experts (SME) from industry and national laboratories regarding HVDC and cybersecurity to advise and instruct the CDS Participants as may be appropriate to supplement the CDS Participants’ expertise.  In addition to their modeling services, CDS subcontractor Hitachi ABB is a supplier of HVDC transmission equipment and services.


       The PftP CDS would be a good opportunity for CDS Participants to familiarize themselves with HVDC.


Q:  Our utility would need more data and modeling to determine if there was a business case for a project like PftP?


A:  Providing such initial strategic planning information for decision-making at a relatively modest cost per CDS Participant while leveraging available resources is the goal of the CDS.


Q:  Who would manage the CDS process?


A:  The PftP LLC Team would manage day-to-day operation of the study.  But the CDS Participants’ Review Committee would provide input, assumptions, review and governance of the CDS activities.  The CDS Participants would receive the CDS results and deliverables.


Q:  If wind energy in Wyoming costs the same as wind energy in Illinois, what is the value of an HVDC transmission connection between them?


A:   Wyoming, Nebraska, the Dakotas and Iowa generally have higher wind speeds than Illinois.  But even if they were similar and cost the same, their wind speeds do not happen at the same time.  There is significant temporal (i.e., time) diversity between their outputs across the geographic distance of the PftP HVDC line and related HVDC developments to its West and East.  That means renewable wind energy would be available to PftP participants more often, at a higher total capacity factor, than looking at a single state alone. 


      Unlike a transmission line built to transmit wind energy from a single state, which is limited in its use to the capacity factor of the wind output there, an interregional HVDC line has the advantage of temporal (time) diversity between the outputs of multiple wind fields.


Q:  Wind energy and natural gas energy currently cost about the same in $/MWh.  What would be the advantage of an interregional HVDC line in such a situation?


A:  The PftP development would provide more, diversified and therefore higher capacity factor wind and solar energy to its participants.  Even if wind and natural gas prices stayed similar, it would be desirable to displace fossil fuels with additional clean energy if it is economically available. Consumers will expect that.


       Natural gas prices are currently low and projected to stay inexpensive.  But Utility Resource Planning “101” reminds us to keep a diversified energy portfolio, and not put all of our resource eggs in one basket.  What if the current natural gas price forecasts turn out to be wrong?  An investment in HVDC, renewables, and perhaps energy storage as well is a hedge against increasing natural gas prices and its associated carbon emissions.  In other words, this project would entail fixed costs based on investment today versus the risk of commodity price increases in the future.


Q:  Has PftP done initial research on the time diversity and long duration storage topics?


A:   Yes.  Our team has done extensive research on the topics of time diversity, interregional transmission and grid-level, long duration storage.  This “thought capital” has been baked into the design of the CDS.  See the Publications page for details.

Q:  How can the CDS capture time diversity in renewables output across large distances?


A:  PftP’s subcontractor, Hitachi ABB Power Grids whose facilities and capabilities the proposed CDS would use, has extensive time-domain data sets of renewable energy potential across the entire U.S.  This data from NREL and other sources captures the time diversity between wind speeds and solar insolation across distances.  ABB’s GridView modeling capability can capture the economic and operational outcomes of this diversity as part of the CDS.

Q:   Can interregional transmission act like long duration energy storage?


A:   Yes.  Storage is the act of sending energy to a medium when there is too much of it, and retrieving it back from the medium when it is needed at a later time.


       With interregional transmission, a utility that is over-generating with its own renewables compared to its load can export the over-generation to other areas.  Later, it can receive contractually-guaranteed renewable energy (not fossil energy) back.  Did actual physical storage happen?  Not necessarily.  The renewable energy coming back could be time-diversified renewable energy form another region. 


      We call this capability of interregional transmission “virtual storage”.  And it is not limited in duration to the size of a battery or a water reservoir.

Q:  Aren’t the potential renewable energy resources in the Upper Midwest too far from markets? 


A:   That is the perspective that has kept them underutilized to-date.  The Upper Midwest has more potential renewable energy production capability than can be used there.  The PftP project proposes to change that by enabling HVDC transmission from those underutilized resources to markets to the East and West that can use them.  This involves using similar existing and proposed HVDC transmission reaching from California to Chicago.


Q:  The draft CDS Statement of Work states that the Eastern end of the PftP line may be located in Northwest Iowa, or Sioux Falls, or Omaha.  Why these destinations, and who decides which will be examined?


A:  These location options were stated in the interest of potential CDS Participants, who will decide what option(s) they want.  A location in Northwest Iowa would directly connect the Iowa wind fields and allow integration with the proposed Rock Island Soo Green HVDC development from there eastward to Indiana.  An Omaha location would make the project primarily Nebraska-oriented.  A Sioux Falls or Brookings connection would facilitate integration of the recently-completed CapX2020 345 kV facilities in Minnesota, Wisconsin and the Dakotas. 


Q:  Is collecting renewable energy across a large geographic area the primary goal of a PftP development?


A:  It is one important goal.  Another goal is to take advantage of the time diversity between utility customer loads across regions to share generation capacity, which would potentially reduce installed capacity reserve requirements and result in cost savings.  Yet another goal is to provide a clean-energy based alternative to legacy fossil and nuclear generation facilities as they are retired.

Q:  The proposed CDS talks primarily about wind energy. Will solar be included in the study too?


A:   Yes.  While the Midwest is an outstanding wind resource, the modeling capabilities and data sources we plan to use are fully capable of including large solar developments in the Midwest in the study.  But that is up to the CDS Participants to decide.


Q:  Our utility is considering a goal of 100% renewable electric energy for our customers.  How would a PftP development relate to that?


A:  Accomplishment of such an aggressive goal cannot depend upon the use of a single state’s intermittent renewable energy resources alone.  They simply do not operate 100% of the time.  Such a goal would require access to diversified renewable energy sources over several states like a PftP development would provide, or large amounts of energy storage, or both.   The CDS would look at both; individually and together.

Q:  Our utility’s service area is some distance from the potential route of PftP.  Isn’t that a barrier to our participation?


A:  It is a consideration, but not a barrier.  A national HVDC transmission grid build-out means the potential reach of a PftP development as an element in the build-out is a wide geographic swath from Los Angeles to Chicago and farther East.  Additionally, there already are several individual HVDC facilities in the Upper Midwest that could eventually be part of such an interconnected build-out to the North and South—to the benefit of their current customers and utility participants.


       The CDS will examine the generic opportunities and challenges of interregional transmission.  The lessons-learned would apply to multiple HVDC projects located elsewhere in the country.


Q:  The CDS proposal includes examination of grid-level storage in South Dakota and Utah operating together with HVDC.  Are these storage projects real?  What is their status?


A:  Both projects are real and in the early stages of development.  The Gregory County pumped hydro storage project in South Dakota has a current FERC preliminary permit for development.  The PftP LLC Team is familiar with and has been involved in both projects.


Q:  If our utility chooses not to participate now, could we review the results of the CDS and potentially join later?


A:   CDS Participants would have the advantages of directly participating in the CDS process and thereby affecting the direction and content of the study and the PftP HVDC project.  While the PftP Team would disseminate and publicize the high-level results of the effort, the CDS Participants would also receive the detailed results and deliverables of the CDS.  It is expected that portions of the CDS will be proprietary, and such results are expected to only serve the interests of the CDS Participants.


      Further distribution of the CDS results or allowing additional participants to join them in a follow-on PftP effort, would be decisions for the CDS Participants to make.


Q:   Is CDS participation limited to utilities, or can wind or transmission investors participate?


A:   Utilities and their customers would stand to benefit from the reduced generation capacity reserves, diversified renewable energy sources, and access to markets across the seam between the Western and Eastern Interconnections that PftP would enable.


       In addition, renewable energy or transmission investors or developers and others would be welcome to participate. 


Q:   If a PftP transmission line were built as a result of the CDS, could an independent developer own the line or portions of it?


A:   Yes, subject to applicable state laws requiring public ownership or incumbent utility Rights of First Refusal (ROFR).


Q:  We now have a new Administration in Washington DC. What are the implications of that for projects like PftP?


A:   It remains to be seen how the new Administration will operate, although it will be favorable to addressing climate change.  PftP is a large infrastructure project that would cost-effectively provide electric energy to consumers and businesses, reducing their electricity costs.  And it would enable clean energy to provide a replacement for existing generation facilities as they continue to age-out and are retired.  And it will provide economic development and jobs for the states involved. That is a good project in any Administration. 


Q:  What are the potential products and benefits of the Concept Development Study (CDS) for the CDS Participants?


A:  The CDS will provide the Participants information in the following areas related to the PftP HVDC transmission line and the additional renewable energy it would enable:


      1.   Cost savings for the Participant utilities’ customers.  How a PftP development would provide additional, high capacity factor                            renewable energy to the Participants, as well as access to additional conventional generation sources from other markets.

      2.   Additional markets for Participant utilities’ generation.  How a PftP development would provide access to additional markets for the               Participants to beneficially sell their surplus generation output, including renewables, when it occurs.


      3.   Achieve higher levels of renewable energy.  The CDS will examine the use of widely-distributed renewable resources whose output               is diversified over time, thereby providing very high capacity factor renewables along the expanse of the PftP line.  And it will                         examine how grid-level storage combined with HVDC might further support additional renewable energy not otherwise possible.


      4.   Reduce carbon emissions.  Regardless of the federal government’s stance on such topics, utility customers now expect                                  reductions in carbon emissions—the kind that would be made possible by a PftP project.


      5.   Examine the potential for importing low-cost solar energy over-generation from California when it occurs.  Adding PftP will                               make HVDC transmission links bi-directional from Chicago to Los Angeles, enabling daily renewable energy swaps                                         between regions.


      6.   Enable retirement of legacy generation resources when it is time to do so.  Conventional generation capacity in the region is not

            getting any younger.  CDS will provide information on how high capacity factor renewable energy might be used to help enable its

            replacement when the time is right.


      7.   Identify other regional entities who would potentially benefit from such a project.  This is a first step in securing additional                  

            transmission line project participants and thereby achieve critical mass for such a project.


      8.   Economic Development.  Citizens and landowners in Nebraska, South Dakota and Wyoming stand to gain from the additional                       wind energy development that would be enabled by PftP.  These states could benefit from a national transition to clean energy.


      9.   Demonstrate leadership.  Involvement in the CDS will feature the Participants as forward-thinking leaders in grid development,                       including renewable energy.


See the CDS Products tab for more details.


Q:  What are the potential downsides of the CDS for the Participants?


A: From the PftP Team’s perspective, there are few potential downsides.  Worst case, even if the CDS determines that PftP development would not be economically beneficial, that is still useful information for the Participants.


Q:  What is the relationship between the CDS and the National Renewable Energy Laboratories (NREL) Interconnections Seam Study?


A:  The Seam Study was an important advancement in the discussion of a national HVDC electric transmission overlay.  It found that such a development would be cost-effective, enable large quantities of renewable energy, and help replace existing fossil-fired generation as it is retired.


      Encouraged by the results of the Seam Study, the CDS is designed to take the topic further toward reality.  The Seam Study was conceptual.  The CDS is project- and utility-specific.  The Seam Study was technical.  The CDS will examine not just technical issues, but organizational, market rules and regulatory as well.


      PftP and its CDS have been designed from the beginning to be the first practical and specific project instantiation of the Seam Study vision.  And to show the way for similar projects elsewhere.


Q:  Please describe the rationale for using GridView model, rather than PROMOD in the CDS.  Our utility uses PROMOD, and we have no experience running Grid View.


A: By definition, a study like CDS that crosses from one Balancing Authority or RTO to another requires selection of some common tools.  The Western Electricity Coordinating Council (WECC) including Wyoming uses GridView.  SPP uses PROMOD.  We have to call it a ball or a strike regarding which should be used for the entire span of the study.


   Our modeling vendor, ABB, is the purveyor of both GridView and PROMOD.  So the choice of CDS vendor does not affect the choice of model to be used.  According to ABB, the underlying structure of PROMOD cannot accommodate the very large dataset size or running time requirements for the CDS like GridView can.


   As part of the CDS effort, ABB will convert standard ABB/MISO PROMOD model datasets into GridView datasets.  So the underlying data will be from PROMOD—not a dataset unique to GridView.   GridView and PROMOD are just different security-constrained production cost models, or calculators.  The CDS Participants will not need to know how to run GridView themselves.  ABB and the PftP team will present changes in production costs, renewables output carbon emissions, conventional generation output, and other key measures when comparing the Base Case and the CDS Scenarios.  Participants who understand PROMOD will be easily able to review corresponding outputs from GridView.


Q:  Does the CDS Participant Agreement obligate the Participants to participate in a PftP transmission project?


A:  No.  It only addresses the process of accomplishing the CDS.  Individual CDS Participants can decide later whether they want to move on to a transmission project, based on results of the CDS.  That is a separate decision.


Q:  The CDS will examine the PftP transmission line in coordination with similar HVDC lines to the West and East of PftP.  How real are these additional lines?


A:  In addition to the PftP line, the CDS will examine the following HVDC lines, which are very real:


  • The Southern Transmission System (STS) HVDCline (2400 MW), which already exists.It extended from Southern California to Delta, Utah.


  • The TransWest Express HVDC line (3,000 MW), which has secured all of its right of way and permits.It extends from Delta, Utah to Southeastern Wyoming.


  • The Soo Green HVDC line (2300 MW) that is currently in the process of formal solicitations for shippers, customers and renewable developers.


Two-thirds of the planned CDS route from Southern California to Chicago is already existing or under advanced development.  The PftP line is the missing link to make these lines “bi-directional”.


Q:  How will Confidential Information be handled during the CDS?


A:  That is a topic addressed in the CDS Participant Agreement.  The CDS results for individual CDS Participants (i.e., economic benefits, generation changes, carbon emissions, etc.) will be held confidential to each Participant.   Individual Participants may, at their sole option, elect to share their own Confidential Information with others.


     Results that are not unique to individual CDS Participants, including aggregated total impacts and benefits to the region identified by the CDS will not be confidential.  In addition, CDS results of potential benefits for individual non-CDS Participant utilities will be shared with the CDS Participants in the interest of identifying potential partners for next steps in the PftP process to achieve critical mass, but would not be released publicly outside the PftP Team and CDS Participants.

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