Public Service of Colorado settles issues with solar, battery projects

Filed on Feb. 19 at the Colorado Public Utilities Commission was a settlement between the Public Service Co. of Colorado unit of Xcel Energy (NYSE: XEL) in a case involving a solar project and a battery storage project.

Public Service, Western Resource Advocates (WRA), the Colorado Energy Office (CEO) and the Energy Freedom Coalition of America (EFCA) filed the statement. The Public Service, the state Office of Consumer Counsel (OCC), commission staff, Western Resource Advocates (WRA), the Colorado Energy Office (CEO) and the Energy Freedom Coalition of America (EFCA) reached the agreement to settle the matters at issue in this proceeding. Public Service previously filed a motion to approve the settlement, and in this Feb. 19 statement, the parties recommend that the commission approve the proposed settlementwithout modification.

In its original application, Public Service proposed two Innovative Clean Technology (ICT) projects designed to expand its understanding of the benefits associated with microgrids and energy storage. The proposed Panasonic project will analyze the costs and benefits of solar generation and battery storage technology, including an associated microgrid at a commercial installation. The Panasonic Project was presented to Public Service as a complete package.

Panasonic and Denver International Airport (DIA) expect to complete construction of the parking structure with a 1.3-MW PV solar installation in or around May 2016. This timeline, and Public Service’s intent to comply with previous commission decisions regarding ICT project processing, informed Public Service’s request for an expedited schedule in this filing. The company said it will need to begin procurement and installation no later than mid March to meet the deadlines for the solar portion of the Panasonic project.

In the proposed Stapleton Project, the company and one or more project partners (to be determined) will deploy batteries on distribution feeders where the company is experiencing high penetrations of distributed solar generation. The project will consist of six distribution system-sited batteries and six customer-sited batteries designed to test performance, interaction with onsite solar, and load-shifting capabilities.

The cost estimates for both projects totaled approximately $10.7 million, which is $6.7 million for the Panasonic solar project and $4 million for the Stapleton battery project.

The agreement addresses four specific areas of settlement: reporting, accounting, Stapleton-specific, and intellectual property.

  • Within timelines specified in the agreement, Public Service will file courtesy copies of documents related to each agreed-upon project milestones. Due to the pending Request for Information (RFI) soliciting partners for the Stapleton Project, EFCA expressed great interest in ensuring that the subsequent Request for Proposals (RFP) was vetted and approved. To accommodate the interests of EFCA and other potentially interested stakeholders, the agreement proposes milestone reports and informational filings at three stages of the Stapleton Project: when Public Service issues the RFP, awards the RFP, and develops test protocols for the project.
  • Accounting and financial matters are usual and customary issues addressed in settlement agreements to provide clear expectations to applicants, customers, and other interested stakeholders regarding the cost and cost treatments associated with proposals.
  • EFCA raised concerns in its testimony about utility ownership of customer-sited batteries in the Stapleton test. Specifically, EFCA expressed concern that by concentrating on utility ownership, the demonstration would fail to identify best practices for integrating customer-sited batteries and would fail to put the company in a position to take advantage of customer and third party-owned distributed resources. The settlement allows Public Service to own the batteries for purposes of the project. However, as stated in the agreement, “Public Service expressly acknowledges that the purpose of this demonstration and proceeding is not to determine precedent for the future regarding the ownership of batteries on the customer side of the meter.” The agreement also clarifies that “a goal of this demonstration project will be to develop best practices for efficiently interconnecting and integrating customer-sited batteries, irrespective of the ownership of those batteries.” EFCA also raised concerns about the lack of smart inverter testing contemplated by either project, and proposed that smart inverters be incorporated into the Stapleton Project since the potential benefits of advanced inverter technology are similar to that of batteries at potentially lower costs. The utility acknowledges the benefit of testing this technology, but testing is currently infeasible until certain functionalities of advanced inverters are UL approved. Public Service will work with stakeholders, including parties to this proceeding, to develop and propose testing of advanced inverter technology within six months of the time that the UL1741 standard is approved and advanced inverters are commercially available.  Also, to resolve EFCA’s concerns regarding the lack of a draft RFP, the settling parties have developed a process whereby the company will develop and present its proposed RFP to stakeholders for review and input prior to filing it with the commission.
  • The settlement also addresses issues of intellectual property (IP) raised specifically by EFCA. As stated in the application, the company does not know whether there will be IP involved in the Stapleton Project, but rather than Public Service automatically retaining all ownership of any IP that may be developed through the course of the project, the settlement allows RFP respondents to include IP proposals in their responses. Public Service will evaluate any such proposals in determining both whether to award the RFP to that vendor and whether any particular IP arrangements should be made.

Public Service had applied last October at the commission for approval of these two projects. These would be the third and fourth Innovative Clean Technology (ICT) projects for the utility.

Rather than simply simulating an environment with high PV penetration, the Stapleton project will be deployed on distribution feeders where the company is experiencing high penetrations of distributed solar generation. In the case of the Panasonic project, the company will be analyzing the benefits of battery storage technology at a location where there is a large commercial installation of distributed solar generation and additionally has functionality as a microgrid.

The Panasonic project consists of three primary components:

  • a 1.3 MW (ac) solar installation;
  • a 1 MW – 2 MWh battery storage system; and
  • the power controls and balance of system.

The solar installation will be owned by Public Service and situated on the parking garage located near the Panasonic building and will be integrated with a high concentration of variable distributed generation within the demonstration area. The storage system will feature a lithium-ion chemical battery that has been sized to enable it to provide the capabilities described above for the benefit of both the company’s distribution system and the host site. A custom power control system designed to manage the battery’s state of charge in a manner which optimizes economic potential will be deployed. Finally, the battery storage system will be set up to enable it to be operated and tested as a microgrid to provide backup power to Panasonic Enterprise Solutions Co. (PESCO) in the event of a grid outage. All assets will be owned and operated by Public Service, with maintenance services being provided by PESCO.

The Stapleton project is expected to consist of utility-sited batteries of varying sizes installed at six different locations along a feeder that already has a significant amount of reverse power flow along with six customer-sited batteries. Battery locations for the utility-sited batteries were identified on either end of the circuit’s half loop and sized to match the entire loop’s reverse power flow. Public Service expects to deploy six utility-sited battery storage systems: two 25 kW – 100 kWh units, two 50 kW – 200 kWh units, and two 75 kW – 300 kWh units.

About Barry Cassell 20414 Articles
Barry Cassell is Chief Analyst for GenerationHub covering coal and emission controls issues, projects and policy. He has covered the coal and power generation industry for more than 24 years, beginning in November 2011 at GenerationHub and prior to that as editor of SNL Energy’s Coal Report. He was formerly with Coal Outlook for 15 years as the publication’s editor and contributing writer, and prior to that he was editor of Coal & Synfuels Technology and associate editor of The Energy Report. He has a bachelor’s degree from Central Michigan University.