Integrating Renewable Energy into the Transmission and Distribution System of the U. S. Virgin Islands

Abstract

Executive SummaryLike 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. Source: NRELAs 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.vi 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 AnalysisThe National Renewable Energy Laboratory (NREL), in partnership with HOMER Energy LLC, developed two models using the Hybrid Optimization Model for Renewable Energy ( The results of the analysis demonstrate the following:• Wind is cost effective at...

U.S. Virgin Islands Energy Road Map: Analysis

“…Such conditions can greatly impact island costs, and hence, island-specific pricing. 21 Additional economic analysis on the relative cost differences between wind and solar PV is included in Burman et al (2011). Detailed power system analysis is also necessary as significant amounts of new variable-output renewable resources are considered. System integration and grid studies, in line with those highlighted in Figure 7, can assist in identifying the specific operational and infrastructure changes and system costs associated with integrating new generation into the USVI grid systems.…”

Information gap decision theory based OPF with HVDC connected wind farms

“…• Advantages : Black start capability [19], no requirement for reactive power compensation, more compact and lighter compared to LCC, no need for harmonic filter, can be operated in both capacitive or inductive modes [20], [21], VSC valves are independent of the zero crossings of the current and balanced operation of the linked AC system, ability to control the negative sequence current injection in the offshore wind power plant [22], shorter design and installation times [15], using IGBT switches enables the VSC-HVDC scheme to be switched on and off at higher rate [23] and needs no external voltage source for commutation [24].…”

“…• Disadvantages : Lower reliability, weak overload capability, higher cost by 10-15% due to high component count, less mature technology, higher converters power losses due to witching operations (1.0-1.5%), limited power capability, not able to suppress DC side fault currents [21]. Both of these HVDC technologies have their own cons and pros and choosing the best technology for HVDC link depends on the requirements of the planner, which is not the subject of this work.…”

Renewable Electricity Futures Study. Volume 1: Exploration of High-Penetration Renewable Electricity Futures

“…Rich with renewable potential (e.g., solar, wind, waste-to-energy), these islands are prime opportunities for renewable generation. Scenario analyses to assess renewable resource potential, similar to that described above for Hawaii, have been completed for the U.S. Virgin Islands, Guam, America Samoa, and the Commonwealth of Northern Mariana Islands (Lantz et al 2011, Davis et al 2011, Burman et al 2011, Baring-Gould et al 2011a, Busche et al 2011, Baring-Gould et al 2011b At such high levels of renewable electricity penetration, the unique characteristics of some renewable resources, specifically geographical distribution and variability and uncertainty in output, pose challenges to the operability of the U.S. electric system. The study focuses on some key technical implications of this environment, exploring whether the U.S. power system can supply electricity to meet customer demand with high levels of renewable electricity, including variable wind and solar generation.…”

“…Rich with renewable potential (e.g., solar, wind, waste-to-energy), these islands are prime opportunities for renewable generation. Scenario analyses to assess renewable resource potential, similar to that described above for Hawaii, have been completed for the U.S. Virgin Islands, Guam, America Samoa, and the Commonwealth of Northern Mariana Islands (Lantz et al 2011, Davis et al 2011, Burman et al 2011, Baring-Gould et al 2011a, Busche et al 2011, Baring-Gould et al 2011b. Detailed technical analyses to identify grid impacts and other potential barriers are required before strategies on high renewable penetration can be contemplated.…”