Integrating Renewable Energy into the Transmission and Distribution System of the U.S. Virgin Islands Kari Burman, Dan Olis, Vahan Gevorgian, Adam Warren, and Robert Butt National Renewable Energy Laboratory Peter Lilienthal and John Glassmire HOMER Energy LLC NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency & Renewable Energy, operated by the Alliance for Sustainable Energy, LLC. Technical Report NREL/TP-7A20-51294 September 2011 Contract No. DE-AC36-08GO28308 Integrating Renewable Energy into the Transmission and Distribution System of the U.S. Virgin Islands Kari Burman, Dan Olis, Vahan Gevorgian, Adam Warren, and Robert Butt National Renewable Energy Laboratory Peter Lilienthal and John Glassmire HOMER Energy LLC Prepared under Task No(s). IDVI.0040 and DE-OE0000111 NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency & Renewable Energy, operated by the Alliance for Sustainable Energy, LLC. National Renewable Energy Laboratory Technical Report 1617 Cole Boulevard NREL/TP-7A20-51294 Golden, Colorado 80401 September 2011 303-275-3000 • www.nrel.gov Contract No. DE-AC36-08GO28308 NOTICE This report was prepared as an account of work sponsored by an agency of the United States government. Neither the United States government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States government or any agency thereof. Available electronically at http://www.osti.gov/bridge Available for a processing fee to U.S. Department of Energy and its contractors, in paper, from: U.S. Department of Energy Office of Scientific and Technical Information P.O. Box 62 Oak Ridge, TN 37831-0062 phone: 865.576.8401 fax: 865.576.5728 email: mailto:[email protected] Available for sale to the public, in paper, from: U.S. Department of Commerce National Technical Information Service 5285 Port Royal Road Springfield, VA 22161 phone: 800.553.6847 fax: 703.605.6900 email: [email protected] online ordering: http://www.ntis.gov/help/ordermethods.aspx Cover Photos: (left to right) PIX 16416, PIX 17423, PIX 16560, PIX 17613, PIX 17436, PIX 17721 Printed on paper containing at least 50% wastepaper, including 10% post consumer waste. Contacts U.S. Department of Energy (DOE) HOMER Energy LLC Dan Birns John Glassmire 202-586-8767 Energy Systems Engineer [email protected] 720-565-4046 [email protected] Steve Lindenberg 202-586-2783 Peter Lilienthal, PhD [email protected] President & CEO, HOMER Energy 2334 Broadway, Suite B National Renewable Energy Laboratory Boulder, CO, 80302 (NREL) 720-565-4046 office 303-447-1392 fax Kari Burman [email protected] 303-384-7558 www.homerenergy.com [email protected] Robert Butt 303-384-7455 [email protected] Vahan Gevorgian, PhD 303-384-6940 [email protected] Dan Olis 303-384-7398 [email protected] Adam Warren, PhD 303-275-4346 [email protected] iii Acknowledgments We would like to acknowledge the U.S. Department of Energy (DOE) for its funding of the Energy Development in Island Nations (EDIN) program and of the island interconnection study, awarded under contract DE-OE0000111. Dan Birns and Steve Lindenberg of DOE provided leadership for our efforts in the U.S. Virgin Islands (USVI). We wish to express our thanks and gratitude to Hugo V. Hodge Jr., executive director (CEO) of the Virgin Islands Water Power Authority (WAPA), and to the WAPA staff on St. Thomas and St. Croix, including Clinton Hedrington, Allyson Gregory, Julio Fung, Kevin Smalls, and Dwight Nicholson. In addition, we wish to thank Juanita Young and Gerry Groner (WAPA Board of Directors) for their invaluable assistance on this project. We would also like to thank the Virgin Islands Energy Office (VIEO), including Director Karl Knight, former Director Bevan Smith, and Miguel Quiñones, for their support of the EDIN- USVI project. The U.S. Department of the Interior’s Basil Ottley was also instrumental in supporting EDIN-USVI work in the territory. The tables and figures in this report are limited to use in this report only and are not to be further disseminated or used without the permission of the sources cited. iv Executive Summary Like many island communities, the U.S. Virgin Islands (USVI) is almost 100% dependent on fossil fuels for electricity and transportation. This total reliance on oil leaves the territory vulnerable to global oil price fluctuations that can have devastating economic effects on individuals and businesses. USVI electricity costs are over four times the U.S. average, making energy price spikes extremely difficult for ratepayers to absorb. And like other island communities around the world, the U.S. Virgin Islands are among the first to feel the impact of the environmental threats associated with fossil fuel-based energy sources—rising sea levels, intense hurricanes, and widespread loss of coral reefs due to ocean acidification. Such risks and hardships incurred by islands offer mounting evidence that the status quo is unsustainable. In the USVI and other island communities, this has created a sense of urgency around the need to dramatically transform the way energy is sourced, generated, and used. In response, islands around the globe have adopted some of the most aggressive clean energy goals. The USVI’s goal is to reduce fossil fuel use 60% from business as usual by 2025. Figure ES-1-1. Comparison of two possible courses for the USVI: the status quo vs. a 60% reduction in fossil fuel use by 2025. Source: NREL As islands reduce their fossil fuel usage, they have an opportunity to lead the rest of the world in transforming our shared energy future. This report describes one area in which islands may lead: integrating a high percentage of renewable energy resources into an isolated grid. In addition, it explores the challenges, feasibility, and potential benefits of interconnecting the USVI grids with the much larger Puerto Rican grid. v The overall objective of the interconnection study is to explore the most economical mix of fossil fuel-based and renewable power generation technologies that can be deployed to enable the USVI to reach its goal. This report focuses on the economic and technical feasibility of integrating renewable energy technologies into the USVI transmission and distribution systems. The report includes three main areas of analysis: • The first area of analysis (Sections 3 and 4 of the report) examines the economics of deploying utility-scale renewable energy technologies, such as photovoltaics (PV) and wind turbines, on the islands of St. Thomas and St. Croix. • The second (Sections 5, 6, and 7) focuses on the potential sites for installing roof- and ground-mount PV systems and wind turbines and investigates the impact renewable generation will have on the electrical subtransmission and distribution infrastructure. • The third (Section 8) summarizes the results of a study to determine the feasibility of a 100–200 megawatt (MW) power interconnection of the Puerto Rico, USVI, and British Virgin Islands (BVI) utility grids via a submarine cable system. Economic Analysis The National Renewable Energy Laboratory (NREL), in partnership with HOMER Energy LLC, developed two models using the Hybrid Optimization Model for Renewable Energy (HOMER) software tool to analyze the electrical generation on St. Thomas/St. John and St. Croix. The models were used to determine the optimal hybrid mix of conventional generation and renewables and the most cost-effective way to meet the island demand loads. The models used solar and wind resource data specific to the region along with 2009–2010 generation and fuel use data provided by the Virgin Islands Water and Power Authority (WAPA) for St. Thomas and St. Croix. The models examined the economic impact of putting 5.5 MW of PV and 15 MW of wind on each island. The model for St. Croix also included a 16.5 MW waste-to-energy (WTE) plant planned for 2012. The results of the analysis demonstrate the following: • Wind is cost effective at fuel prices as low as $58.66$/barrel. • 15 MW of wind can reduce fuel usage by 9% on St. Thomas and 14% on St. Croix. • PV becomes cost effective when installed costs drop below $5.50/watt (W) on St. Thomas and below $5.00/W on St. Croix, or when fuel prices exceed $99/barrel. • Under the proposed power purchase agreement (PPA), modeling indicates the 16.5 MW WTE plant is cost effective. WTE is also cost effective when combined with PV and wind. The high-level economic results suggest that the recently released solar request for proposals (RFPs) will garner acceptable responses. More detailed financial models are currently under way to understand the variables that affect PV costs in the USVI. Overall, wind turbines appear to be the most economically feasible alternative energy technology, even with very conservative assumptions. Further detailed studies should be done to obtain quality wind resource data at identified sites. vi Site Selection and Impacts on the Electrical Power System In preparation for WAPA to release an RFP for PV, NREL worked with WAPA personnel to identify rooftops and/or cleared areas that were suitable for PV deployment. A number of criteria were included in this analysis, including potential site shading, geography, proximity to the feeders, and site ownership.