The Long Road to Community Microgrids

By Efraín O’Neill-Carrillo, Isaac Jordán, Agustín Irizarry-Rivera, and Rafael Cintrón

Adapting to the necessary icrogrids offer tremendous opportunities in isolated areas or developing changes for renewable countries that are unable to establish a tra- energy implementation. M ditional power infrastructure. However, microgrids face vast challenges in places where the dominant model is based on a centralized, hier- archical infrastructure with policies and institutions developed to support such infrastructure. Renewable ener- Digital Object Identifier 10.1109/MELE.2018.2871239 Date of publication: 16 November 2018 gy researchers at the University of Puerto Rico–Mayaguez

6 IEEE Electrification Magazine / December 2018 2325-5987/18©2018IEEE (UPRM) have traveled a long road advocating 2010. In 2008, researchers at UPRM quantified the poten- distributed energy resources (DERs) and com- tial for electricity generated from local renewable energy munity microgrids. sources. They found that the best renewable resource with commercially available technology in Puerto Rico is Overview of Electric the sun (Figure 2). Figure 3 shows the potential for gener- Energy in Puerto Rico ating solar electricity using photovoltaic (PV) panels on In 1941, the Puerto Rico Water Resources residential rooftops. All of the electric energy in Puerto Authority (AFF, its acronym in Spanish) was Rico could come from using PV systems in 65% of resi- created as a public power company to plan, dential rooftops once we obtain an efficient, cost-effec- design, construct, operate, and maintain tive, and environmentally sound technology to store Puerto Rico’s electric infrastructure. As part of electric energy for use at night. Figure 4 shows results a plan to take many Puerto Ricans out of the from another UPRM study [funded by the U.S. Depart- dire conditions they lived in the 1930s, Anto- ment of Energy (DOE)] proving that residential rooftop PV nio Lucchetti proposed to integrate all of the systems already had an average cost of between 11 and electric power systems in Puerto Rico. War- 12 cents per kWh in 2013 (assuming an installed cost of time circumstances enabled the final acquisi- US$3 per watt, net metering, and four hours of “peak tion of private power companies, which sun”). In contrast to most U.S. jurisdictions, rooftop PV helped the AFF complete its mission: the systems with net metering have been economically fea- electrification of Puerto Rico. sible in Puerto Rico since at least 2010, reaching grid pari- The AFF accomplished its founding mis- ty near that time. sion in the 1970s. While its name changed to A key challenge is to turn the potential for renewable the Puerto Rico Electric Power Authority energy into a reality through a safe and reliable grid con- (PREPA) in 1979, its mission stayed the same. nection. The differing opinions regarding this matter result As of December 2018, PREPA is a vertically from the fact that traditional power systems were built and integrated utility and is one of the largest operated based on the assumptions of that time. Conse- public power companies in the United States, quently many electric companies around the world (includ- and remains the only provider of retail elec- ing PREPA) have usually reacted negatively to renewable tricity on the island (Figure 1). It has more energy, believing that it complicates conventional power than 2,400 mi of transmission lines (230 and system operation. Despite these challenges, distributed

mountain: ©istockphoto.com/alejandrophotography, mountain: ingram publishing licensed by solar panels—image 115 kV), 51 115-kV transmission centers, 283 generation continues to grow in Puerto Rico, furthered by subtransmission substations (38 kV), and the passing of Act 133 in 2016, which permits solar commu- over 30,000 mi of distribution lines (13.2, 8.32, nities and microgrids on the island. 7.2, and 4.16 kV). New technologies, practices, and oppor- PREPA’s mission was finally updated in 2014 to reflect a tunities were missed because of the lack of a renewed new mandate toward a sustainable energy future. A new mission to face the challenges of the latter quarter of the regulator, the Puerto Rico Energy Commission, was created 20th century and begin an ordered and comprehensive transformation of the electric infrastructure, its business structure, and custom- 728 MW er service. On the other hand, 248 MW Dos Bocas 840 MW Caonillas Cambalache Palo Seco there was no holistic planning or San Juan integration of energy strategies and technologies in Puerto Rico, Rio Blanco 220 MW and changes in energy policy direc- Mayaguez tions (due to excessive partisan inter- ventions in PREPA) were an obstacle Garzas I and II for decades. Toro Negro I and II An area of disagreement in the Yauco I and II last 20 years between PREPA’s AES Costa Sur ecoEléctrica Aguirre management and electricity users 507 MW 454 MW 1,032 MW 1,534 MW has been the use of renewable Oil (6, 2, or Diesel) Not Shown: 386 MW from Smaller Units Distributed sources to produce electricity. In Hydro (100 MW) spite of PREPA’s narrow planning Coal Around the Island Installed Capacity: 5,839 MW (3,443 MW in the South) vision, a net-metering law was Natural Gas enacted in 2007, and a renewable portfolio standard became law in Figure 1. The installed generating capacity in Puerto Rico. (Image courtesy of Dr. Agustín Irizarry.)

IEEE Electrification Magazine / December 2018 7 Barceloneta Vega Baja Toa Baja Quebradillas Hatillo Carolina Manati Vega Alta Cataño Canovanas Dorado Aguadilla Rincón San Loiza Isabela Arecibo Moca Camuy Juan Aguada San Florida Toa Alta Trujillo Río Luquillo Morovis Sebastián Corozal Alto Grande Fajardo Bayamón Añasco Ciales Guaynabo Lares Utuado Naranjito Aguas Gurabo Ceiba Las Marías Orocovis Buenas Juncos Naguabo Mayagüez Comerio Jayuya Barranquitas Caguas Hormigueros Maricao Adjuntas Cidra San Villalba Aibonito Humacao San Lorenzo Coamo Cayey Germán Yauco Ponce Yabucoa Cabo Juana Las Rojo Lajas Díaz Santa Salinas Piedras Guánica Isabel Guayama Maunabo Sabana Guayanilla Peñuelas Patillas Grande Arroyo

1,495 → 3.4 h 1,952 → 4.5 h 2,408 → 5.5 h 1,343 → 3.1 h 1,800 → 4.1 h 2,256 → 5.2 h 1,191 → 2.7 h 1,648 → 3.8 h 2,104 → 4.8 h

Figure 2. The annual average insolation in kWh/m2 and peak sun hours.

in 2014. Also in that year, PREPA began a restructuring pro- 40 cess to address the financial problems that had been 35 evident since the early 2000s. The existing electric infra- 30 structure was built for an industrial economy, but the loss 25 of 1,000 industrial clients left Puerto Rico with a generation 20 overcapacity. The decade between 2007 and 2017 saw a 15 48% reduction in industrial demand (after its 2006 peak), a 10 13% loss in the residential sector (after its 2005 peak), and a

Annual GWh Generated 5 10% loss in commercial demand (after its 2007 peak). In 0 2017, PREPA filed for bankruptcy protection under Title III 0102030405060708090 100 of the Puerto Rico Oversight, Management, and Economic Available Rooftop Area (%) Stability Act, a U.S. law. One option for overcoming PREPA’s Figure 3. The potential for electricity production from residential roof- difficult circumstances is to facilitate the use of DERs, top PV systems. which present an opportunity for local socioeconomic development—if priority is given to renewable energy in a hybrid system that enables solar communities Levelized Cost of Energy (LCOE), US$/kWh and microgrids. (Net Metering, 20 Years, 1% Annual Degradation) US$0.25 0.22 0.19 Renewable-Driven Microgrids US$0.20 EI Yunque 0.18 0.16 In Puerto Rico, approximately 70% of US$0.15 0.15 0.13 0.17 0.13 0.12 0.11 the population lives in areas with an 0.15 0.13 US$0.10 excellent solar resource (Figure 2). 0.12 0.11

US$/kWh 0.10 0.09 Adjuntas, Canóvanas, 0.09 0.08 Hence, rooftop PV systems in Puerto US$0.05 Cabo Rojo Sur Mayaguez Norte Guánica Rico have greater potential when US$0.00 compared to other renewable re 2.5 3 3.5 4 4.5 5 5.5 sources. PV systems have some Peak Sun Hours drawbacks, however, such as the LCOE 4 US$/W LCOE 3 US$/W fluctuation of output power, which depends on weather conditions. One Figure 4. The cost per kilowatthour of residential rooftop PV systems. way to increase the penetration of

8 IEEE Electrification Magazine / December 2018 PV generation is to add energy storage One option for per group (12.8 kWh per house). Loads devices. With storage and a dedicated were simulated with one of three control system, PV generators can be overcoming PREPA’s demand profiles: 100 houses used transitioned to serve the role of an 834 kWh per day, 50 houses used active generator and provide more difficult circum 918 kWh per day, and 50 houses used flexibility for system operators and stances is to 627 kWh per day. Each grouping of users. This approach is limited by the houses had a different combination of economic and environmental issues facilitate the use profiles and was not uniformly dis- related to existing storage technolo- tributed. Load reductions represented gies. Another way to increase the use of DERs, which present DR actions. When load reduction was of rooftop PV systems is by managing an opportunity for triggered, the 834- and 918-kWh pro- the demand through demand-response files were reduced by 33%, while the (DR) strategies, which can be used to local socioeconomic 627-kWh profile was reduced by 25%. match load profiles to available renew- Demanding a constant block of able energy production. development—if electric energy from the utility mini- It is well known that many commu- priority is given to mizes the impact resulting from the nity-led efforts in Puerto Rico have interconnection of renewable sources. yielded better results when dealing renewable energy The goal is to overcome two main with local problems than top-down objections from utilities regarding the approaches. There are many well-orga- in a hybrid system penetration of renewable energy: fluc- nized communities in Puerto Rico that that enables solar tuation in power output and unbal- share a common, albeit local, vision of anced energy generation (mainly from their future and use this vision to communities and PV) that produces energy only during inspire the actions of many local volun- the day. At the transmission level, teers eager to improve their communi- microgrids. where the stability of the whole sys- ties. They put their community first, tem is at stake and varying power may ahead of other considerations such as cause a significant variable operation- political party bickering. Thus, combining these ongoing al cost, electric utilities often penalize connected clients if community-based efforts with DERs (including DR) could they violate the LF agreement in the service contract: enable local energy options in support of socioeconomic development and community well-being. In the near future, averageload LF = . this could lead to well-planned community microgrids in maximumloadingiven period Puerto Rico. LF in a solar-community microgrid would greatly Technical Feasibility Study depend on the mix of installed solar-generation capacity, of a Community Microgrid storage, and demand peaks. Moreover, without a good A zero or low-net-energy community microgrid is one that resource-management plan, achieving a high LF could be has sufficient resources to locally manage its demand, difficult and/or costly. Simulation scenarios were used to thereby minimizing its impact on the power grid. A study study the behavior of a microgrid with different levels of of the possibility for a community microgrid serving an PV capacity and weather conditions, indicating that differ- actual community in southern Puerto Rico divided the ent approaches to mitigate and improve LF should be pur- community into 20 groups of ten houses, each with PV sys- sued depending on the conditions and available resources. tems and energy storage. PV systems and energy storage On sunny days, the state of charge of the energy storage were simulated as aggregated systems for each grouping of could reach 100%; if this happens, the storage would be ten houses, as shown in Figure 5. The battery’s state of disconnected and the excess renewable energy injected charge was modeled by adding or subtracting the energy into the grid, thus drastically reducing the LF. One sent or received by the microgrid and obtaining output approach to mitigate the inevitable LF reduction is to decisions from a fuzzy logic controller. The microgrid was charge the battery at a slower rate and reduce the amount grid connected, and the power it delivered could not of energy coming from the grid. Of course, an LF near one exceed a certain amount using the highest possible load would be impossible because of the grid reduction that factor (LF) (i.e., near constant demand). The grid was mod- occurs from charging the battery more slowly; however, it eled as an infinite bus. is preferable to disconnecting the battery altogether, Each grouping of ten houses was connected to a which would send excess renewable energy production to 75-kVA distribution transformer. The aggregated PV sys- the grid, thereby drastically lowering the LF. tem varied from 10 to 20 kW per group (1 to 2 kW per Table 1 shows how the LF is affected when grid depen- house), and the aggregated battery storage was 128 kWh dence is decreased and the installed renewable-generation

IEEE Electrification Magazine / December 2018 9 IL4_8 Load4_I_8 IL CC Load CC House 3 IL3_8 Load3_I_8 House 2 IL2_8 IL 10_8 Load2_I_8 Load 10_I_8 House 1 IL1_8 IL 9_8 Load1_I_8 Load 9_I_8 y y_8 Batter y_I_8 Ibatter IL 8_8 Batter Load 8_I_8 Solar Panel Ipv_8 IL 7_8 Load 7_I_8 y_Ah1 PV_I_8 Batter V + – + Isec_8 Vsec_8 IL 6_8 Load 6_I_8 2 3 1 One group of houses on the microgrid. (Image modeling courtesy of Isaac Jordan using Simulink.) Transformer IL 5_8 Pole-Mounted Load 5_I_8 Figure 5.

10 IEEE Electrification Magazine / December 2018 capacity increased, while the amount During a good managing the energy demand coming of storage remains the same. However, from the grid by considering the mi the degree to which it is affected insolation day and crogrid’s resources, while the second varies tremendously according to focuses on managing internal demand. weather conditions; in sunny scenar- if the batteries are In a solar-community microgrid, man- ios, the LF is reduced as one moves charged or nearly aging the demand from the grid could toward more renewable-generation bring economic benefits; the microgrid capacity and/or less grid dependence charged, the operator could determine, based on the on zero net. Nevertheless, there are status of microgrid resources, the best exceptions, e.g., in cases 2 and 3, the microgrid operator strategy for operating the microgrid system has a slightly better LF when can demand less reliably and economically. For example, it has more solar-generation capaci- during a good insolation day and if the ty installed, which means that case 3 energy from the grid batteries are charged or nearly charged, is the desirable operating point for the microgrid operator can demand the microgrid. Case 3 has an LF simi- during times when less energy from the grid during times lar to case 1 (0.89 versus 0.91) and has the energy prices when the energy prices are high. more renewable-generation capacity Taking as an example the time-of- installed. In a cloudy scenario, LF is are high. use rate for its simplicity, cases 9 and more dependent on the mix, and one 10 with DR simulated a change in peak can see many variations that are demand, i.e., when energy prices are reduced significantly as zero net is approached. higher (see Table 1). In case 9, the microgrid needs In the scenarios, LF improves as more renewable capaci- 10 kW of power per group of ten houses from the grid off ty is installed, while requiring the same amount of energy peak. When the night peak is reached, the microgrid from the grid. When the required grid energy is reduced, reduces its demand to 8 kW per group; the same scenario cloudy days have a more severe impact than sunny days if occurs in case 10, but with their respective boundaries. the installed renewable capacity increases. The gap increase In contrast to a sunny day, for a cloudy-day scenarios, no between sunny days and cloudy days makes microgrid demand reduction is made because not enough energy is operation more difficult, especially in cloudy-day scenarios. produced to completely charge the battery; therefore, the LF It would be possible to require more energy from the grid on and renewable generation on cloudy days in Table 1 cor cloudy days and less on sunny days, but the microgrid oper- respond to a nondemand grid-reduction scenario. This ation cost will rise. Additionally, this solution moves in the demand-side management strategy can help tackle the big opposite direction of zero-net energy. Overall, the microgrid energy gap problem that exists between sunny days and operation maintains a good LF on sunny days and cloudy days when DR is used. On sunny days, Table 1. The LF and renewable generation for sunny and an LF improvement of more than cloudy days. 0.5 is easily achieved, as com- Secondary Installed Sunny/Cloudy pared to scenarios with no DR Case Demand Goal PV Capacity Sunny/ Renewable and no energy storage. Number per Group per Group Cloudy LF Generation (%) Going to net-zero is a real challenge because the LF is reduced 1 10 kW 10 kW 0.91 0.92 27 14 regardless of the scenario, as 2 7.5 kW 10 kW 0.86 0.38 27 14 shown in Table 1. Case 5 is the 3 7.5 kW 15 kW 0.89 0.67 40 22 only scenario in the community 4 6.5 kW 15 kW 0.81 0.33 40 22 microgrid that generated more than half its electric energy from 5 6.5 kW 20 kW 0.77 0.51 53 29 renewables when power from 6 No DR, no 10 kW 0.33 0.38 27 14 the grid was at its lowest (PV-in energy storage stallation capacity is the highest 7 No DR, no 15 kW 0.27 0.35 40 22 of all, and additional renew- energy storage able generation occurs only on a 8 No DR, no 20 kW 0.21 0.32 53 29 sunny day). energy storage There are essentially two per- spectives of demand-side man- 9 8–10 kW 10 kW 0.85 0.92 27 14 agement in a solar-community 10 7–8 kW 15 kW 0.85 0.85 40 22 microgrid. The first focuses on

IEEE Electrification Magazine / December 2018 11 cloudy days. From the perspective of the microgrid communities should make them lower; these findings are user, this is only a demand-side management strategy; summarized in Table 2. Solar PV panels, pure sine wave microgrid users did not respond to a price change (the inverters, charge controllers, and general materials (e.g., microgrid operator did), so, from the utility’s perspective, conductors, boxes, connectors, tubing, and screws) cost the client (the microgrid as a whole) responds to a price approximately US$0.71/W, US$0.18/W, US$0.07/W, and change during peak hours, thereby demanding less energy. US$0.45/W, respectively. The total cost of the materials and Thus, from a utility perspective, the microgrid is a DR user. equipment (not including batteries) is US$1.41/W. This same line of thought can be implemented for other Table 2 also shows a range of costs for design, installa- types of electric rates. This work motivated UPRM research- tion, and certification. These figures come from a set of ers to continue advocating for DERs and, eventually, actual quotes obtained over the same time period. Note microgrids in Puerto Rico. that the design and certification cost ranges US$1–2.20/W. The installation cost has an even wider range, US$0.40– Cost Estimates 1.50/W. The amount does include the installation cost of UPRM researchers studied the residential rooftop PV costs batteries. The capital cost of batteries is discussed later in up to October 2017. The analysis focused on buying equip- this article. The resulting cost is shown in Figure 6. ment and materials for a solar PV system in the range of The lower (green) curve in Figure 6 shows the cost of 1–5 kW. Because these are retail costs, bulk purchasing for the system were it to be installed by the owner. The mid- dle (red) curve is the installed cost of the system, with a low-end of US$1.40/W for design, installation, and certifi- Table 2. The actual cost for a residential cation. The upper (blue) curve is the installed cost of the rooftop PV system (1–5 kW). system, with a high end of US$3.70/W for design, installation, and certification. Many PV installers or companies Cost in Dollars follow the red curve (or even lower), proving the existence Component/Task per Watt (US$/W) of a very competitive local PV market in Puerto Rico, yield- PV panels 0.71 ing economic benefits that stay in the particular commu- Inverter 0.18 nity. In contrast, large power plants burn fossil fuels, which have an environmental impact and many fewer Charge controller 0.07 economic benefits. Figure 6 also shows the downward Balance of system 0.45 trend in rooftop PV costs when compared to the 2013 Subtotal (do it yourself) 1.41 costs presented in Figure 4. For stand-alone (and, eventually, microgrid) operations, Installation (estimate) 0.4 to 1.5 storage is needed. Lead-acid flooded batteries can be pur- Design, permitting (estimate) 1–2.2 chased for US$100/kWh. For the system size considered in Total 2.81 to 5.11 the analysis, a 10-kWh battery storage subsystem was selected; these batteries, operated at 50% discharge and

LCOE, US$/kWh (Net Metering, 20 Years, 1% Annual Degradation) 30 28.5 25 19.2 20 15.7 14 15 10.6 ¢/kWh 10 7.9 7.7 5.3 5 3.9 0 2.5 3 3.5 4 4.5 5 5.5 6 Peak Sun Hours

1.41 US$/W 2.81 US$/W 5.11 US$/W

Figure 6. The PV costs as a function of location in Puerto Rico, not including the cost of batteries.

12 IEEE Electrification Magazine / December 2018 have an estimated life of three years. Because most PV and financial issues. Every community is different; there- panels, inverters, and charge controllers have a warranty fore, the process of implementing microgrids can be cum- of at least 20 years, we assume that in 21 years seven bat- bersome for an electric industry accustomed to technical tery changes will be needed, resulting in a high-end cost standards and regulatory certainty. As part of social con- of US$7,000 over the life of the system. Battery cost is siderations, citizens must be engaged through community expected to continue declining, and assuming a “round- training and capacity building to help facilitate the transi- trip” efficiency of 90%, the cost of storing electric energy is tion to a more distributed electric sector. Furthermore, approximately US$0.18/kWh. there is a need within the utility industry for workforce Thus, the total cost of electricity in this stand-alone development that addresses not only technical matters, system ranges from lower than US$0.23 to US$0.29/kWh. At but also the broader social issues related to distributed US$75/bbl, oil electricity from the grid costs US$0.277/kWh. energy generation and microgrids. Note that this last amount was calculated using PREPA’s UPRM is a core member of the Center for Grid Engi- outdated basic tariff of US$0.05/kWh (residential), which neering Education (GridEd), a DOE-sponsored project led has not been evaluated since 1989. The actual basic tariff by the Electric Power Research Institute. GridEd spon- should range US$0.08–0.10/kWh, creating grid parity with sored two colloquia on solar communities held in April a stand-alone solar PV system that includes batteries. 2017, one in Ponce (Southern Puerto Rico) and another Furthermore, because these are purely cost estimates, in Bayamón (Northern Puerto Rico) (Figure 10). Roughly they do not include or account for sustainability or resiliency metrics/credits that would tilt the balance in favor of renewable-based systems. Puerto Rico is, therefore, ready to begin its transition to an electric infrastructure that favors local DERs, a move that would also support local socioeconomic activity and provide increased resil- Community iency in facing future natural disasters. Center

Transition to Community Microgrids Community microgrids could be established if only a few houses have rooftop PV systems; if those individuals agree to share the responsibilities and benefits, they could cre- ate a solar community (Figure 7). As this solar community grows, and if enough DERs are locally available, a community microgrid could be established. The flowchart in Fig- ure 8 illustrates one possible process. This process has been studied at UPRM since 2009, yielding three master’s theses and various undergraduate capstone design projects. During the spring 2018, four under- Figure 7. A three-house solar community and the community center graduate students further developed the community building. microgrid presented in the feasibility study discussed previously. They increased the number of houses to 238, updated distribution transform- As more people in the community ers with the actual capacity of each, Only a few houses install solar systems, the have PV installed. distribution system limit is and improved load profiles so that reached. they were closer to actual community-demand profiles. The students also completed initial work on protection and communication issues related to the microgrid. Figure 9 shows the updated system for the proposed community microgrid. Solar community: Existing Community microgrid: PV systems and aggregated more investment in Capacity Building and demand are coordinated to an energy storage and increase solar energy use. management system. Workforce Development The social dimensions of renewable energy and microgrids are even more difficult than the technical Figure 8. A diagram of the movement toward a community microgrid.

IEEE Electrification Magazine / December 2018 13 Substation Transformer EPS 1.3 mi

38–4.16 kV

578 ft 640 ft 177 ft T 2T 20 345 ft T 14 × 16 × 16 × 20 275.25 kWh 256 kWh 50 kVa 245.75 kWh 75 kVa 50 kVa 588 ft 319 ft T 17

T 4 T 8 393 ft × 8 × 10* × 12 131.25 kWh 209.5 kWh 209.5 kWh 25 kVa 75 kVa 75 kVa

T 1 626 ft T 18

T 10 325 ft × 14 × 5 432 ft × 8 128.5 kWh 223.25 kWh 75 kVa 107 kWh 50 kVa 50 kVa 571 ft 518 ft T 16

T 3 T 9 605 ft × 11 × 17 × 17 171.25 kWh 236 kWh 245.75 kWh 50 kVa 50 kVa 50 kVa 588 ft 352 ft T 19 T 11 819 ft T 15 × 10 × 11 × 5 244 kWh 187.5 kWh 76.5 kWh 75 kVa 75 kVa 75 kVa 679 ft 536 ft T 6 T 12 100 ft T 13 × 16 × 7 × 6 114.5 kWh 246 kWh 50 kVa 97.25 kWh 75 kVa 75 kVa

T 5 720 ft × 22

358.75 kWh 75 kVa

T 7 544 ft × 8

144.75 kWh 50 kVa

Figure 9. The updated system information for community microgrid analysis, including a connection to the electric power system (EPS).

(a) (b)

Figure 10. (a) An open discussion during the first colloquim and (b) a poster presentation during the second colloquim. (Photos courtesy of Efraín O’Neill-Carrillo.)

14 IEEE Electrification Magazine / December 2018 150 attendees participated in these community-engage- researchers have been collaborating with that community ment and outreach events. Participants were mostly in various capacity-building activities. These include semi- community leaders, although, for each meeting, key nars open to the community and two series of workshops expert collaborators (between 12 and 20) were also for community high schoolers and young adults. Through invited. The main purpose of the colloquia was to pres- that collaboration between an actual community and ent the concept of solar communities, its potential local UPRM, the process described in Figure 8 has been imple- socioeconomic benefits, and its technical challenges. mented, and the first PV system has been installed in the The work was structured around written assignments community’s common building (Figure 12). It serves not participants completed as members of groups. For the only as an electric energy source but also as an educa- final exercise, each group was asked to envision mem- tional tool and a step toward a solar community and bers’ ideal solar community and shared their thoughts in a written poster The most important question asked of participants 1% 1% concerned the management of the solar community. Figure 11 shows that community participants over- 7% whelmingly supported either themselves (39%) or the 13% community in collaboration with the utility (39%). Results from the expert collaborators participating in Ponce and Bayamón were also interesting; in Ponce, most of the col- 39% laborators favored a shared management between the community and utility (60%), while, in Bayamón, 43% of the collaborators favored the community as the sole 39% manager, and 29% favored a collaboration between community and developer. These results might reflect the regional nature of the collaborators’ experiences. One thing is certain: there is strong agreement on the central role the community must play in the establishment of a solar community. These findings are more important now Utility Private Developer than ever before, given the slow recovery of electric ser- Community Community and Utility vice in many rural, isolated communities following Hurri- Community and Community, Utility and cane María in 2017. Developer Academia, Developer The feasibility study described earlier was based on information obtained by undergraduate students in a Figure 11. The community leaders’ preferences regarding ownership capstone course during spring 2015. Since then, UPRM of solar-community systems.

(a) (b)

Figure 12. The beginning of a community microgrid: (a) the rooftop solar panels and (b) the rest of the rooftop PV system. (Photos courtesy of Efraín O’Neill-Carrillo.)

IEEE Electrification Magazine / December 2018 15 microgrid. In May 2018, the commu- As part of a Lessons Learned from nity secured funds to acquire more Hurricane María rooftop PV systems that will be man- university-based On 20 September 2017, Hurricane aged as a solar community. Support María, the most devastating hurricane from UPRM researchers was a vital workforce in the territory’s modern history, hit component in the community’s sus- development Puerto Rico and forever changed the tainability journey. lives of more than 3 million residents. As part of a university-based work program, Dr. Fabio The hurricane proved that the central- force development program, Dr. Fabio ized electric power model is insuffi- Andrade and his team developed a Andrade and his cient for facing natural disasters in the microgrid test bed at UPRM to teach team developed a Caribbean. The system failed for sever- students and communities about al reasons, e.g., a centralized electric the challenges and opportunities of microgrid test bed system, years of neglect in grid main- microgrids (Figure 13). The main tenance, and the sheer force from a components of the test bed are a hard at UPRM to teach hurricane that missed Category 5 sta- ware-in-the-loop interface, four 2.2-kW students and tus by one mile. The local prepared- inverters, and controllable loads. Some ness and response to disasters must of the experiments/demonstrations communities about change. The terrible aftermath of Maria performed include droop control and presents opportunities to further DERs, virtual impedance, control of islanded the challenges and solar communities, and microgrids in microgrids, and DR. The test bed is a opportunities of Puerto Rico, especially in rural and re practical tool for studying the issues mote areas that had no power for related to microgrid implementation in microgrids. months after the storm. Puerto Rico. UPRM researchers and students, with support from the IEEE (in particular the IEEE Engineering Projects in Community Service program) and projects such as GridEd, designed, tested, and deployed as part of an “Oasis of Light” effort at four locations in Puerto Rico that had no electricity after Hurri- cane María hit. Each oasis had roughly 1 kW of solar panels and approximately 4 kWh of storage (Figure 14), providing each community with enough power to charge small electronic devices and a small refrigerator for storing medicine. In addition to providing some relief, each oasis also served as an opportunity to educate Puerto Rico’s residents on renewable energy, DERs, and microgrids. Basic information about energy use and renewables was displayed at each oasis. Figure 13. A microgrid test bed at the UPRM. (Photo courtesy of The new reality of Puerto Rico’s electric sector is one Dr. Fabio Andrade.) based on diminished electric demand, an increased

(a) (b) (c)

Figure 14. (a)–(c) The Oasis of Light relief effort after Hurricane María. [Photo (a) courtesy of Jonathan Castillo, photo (b) courtesy of Efraín O’Neill-Carrillo, and photo (c) courtesy of Rafael Rosario.]

16 IEEE Electrification Magazine / December 2018 emphasis on efficiency, and a strong These findings are training the workforce and also new interest in using renewable energy. levels of user engagement. Partner- The existing model, based on large more important now ships among academia, industry, and fossil-fuel power plants and passive communities are essential in this new users, is insufficient for addressing than ever before, era and would further local initiatives the challenges facing Puerto Rico’s given the slow such as solar communities and com- electric infrastructure. The Oasis ini- munity microgrids in support of tiative showed that there is a better, recovery of electric increased sustainability and resilience. more resilient alternative to centralized power systems, i.e., a hybrid sys- service in many For Further Reading tem with DERs (which would yield a rural, isolated A. A. Irizarry, J. A. Colucci, and E. O’Neill- more sustainable and resilient elec- Carrillo. (2009). Achievable renewable energy targets for Puerto Rico’s renew- tric infrastructure) and, eventually, communities able energy portfolio standard. Energy microgrids. As of August 2018, the Affairs Administration. Puerto Rico. continuous efforts of advocates for following Hurricane [Online]. Available: https://bibliotecale DERs yielded the first two communi- María in 2017. galambiental.files.wordpress.com/2013/12/ ty microgrids and the first microgrid achievable-renewable-energy-targets- fo-p-r.pdf regulation published by the Puerto E. O’Neill-Carrillo, A. Figueroa, and A. Rico Energy Commission (the local regulator). Irizarry. (2013). Improved permitting and interconnection pro- cesses for rooftop PV systems. Energy Affairs Administra- Conclusions tion. Puerto Rico. [Online]. Available: http://prsolar.ece The road ahead will be difficult, and all of the stakehold- .uprm.edu/docs/Rooftop-PV-Systems-Book.pdf A. Skibell. (2016, May 2). How a stubborn utility and aging ers should recognize that renewable energy sources are grid added to island’s woes. E&E News. [Online]. Available: different from conventional electric power. If renewable http://www.eenews.net/stories/1060036577 energy use is to be maximized, the grid needs to change. E. O’Neill-Carrillo, R. Santiago, Z. Méndez, H. Vega, J. This change must encompass not only integrating Mussa, and J. Rentas, “Capstone design projects as foundation renewables (which assumes that the grid remains for a solar community,” in Proc. 47th ASEE/IEEE Frontiers in Edu- cation Conf., 2017, pp. 1–9. essentially the same) but also a new grid. This grid G. A. Carrión, R. A. Cintrón, M. A. Rodríguez, W. E. Sanabria, would provide the flexibility needed to use renewable R. Reyes, E. O’Neill-Carrillo “Community microgrids to in energy as the first option, combined with aggressive crease local resiliency,” in Proc. IEEE Int. Symp. Technology and conservation and efficiency initiatives as well as active Society (ISTAS), Nov. 2018. participation from users (e.g., through DR programs). R. Reyes and E. O’Neill-Carrillo, “Optimal use of distributed resources to control energy variances in microgrids,” in Thus, the business model of any organization that Proc. 7th World Conf. Photovoltaic Energy Conversion, June 2018. wants to be involved in electric energy in Puerto Rico [Online]. Available: https://peer.asee.org/27008. must be expanded from merely selling electricity to E. O’Neill-Carrillo, A. A. Irizarry-Rivera, C. Ortiz, M. Pérez- “providing energy services” in support of increased use Lugo. “The role of engineers as policy entrepreneurs toward of renewable energy. energy transformations,” in Proc. 123rd ASEE Annu. Conf., 2016. doi: 10.18260/p.27008. It took the destruction of half the transmission system E. O’Neill-Carrillo, “Energy policies in Puerto Rico and and most of the main distribution lines to reach consen- their impact on the likelihood of a resilient and sustainable sus that Puerto Rico needs a significant transformation of electric power infrastructure,” J. Center Puerto Rican Studies, vol. its electric infrastructure. This should be a lesson to the 30, no. 3, Nov. 2018. utility industry, in general, to not wait for extreme circum- M. Galluci, “Rebuilding Puerto Rico’s power grid,” IEEE Spectr., vol. 55, no. 5, pp. 30–38, 2018. stances (e.g., natural disasters or financial distress) to eval- uate resiliency options, embrace more aggressive customer engagement, and pursue alternative ways to plan, design, Biographies build, and operate the electric infrastructure. Efraín O’Neill-Carrillo ([email protected]) is with the The industry must look for a more holistic approach to University of Puerto Rico-Mayaguez. planning, with an understanding that the challenges go Isaac Jordán ([email protected]) is with the Univer- beyond technical and economic matters and are usually sity of Puerto Rico-Mayaguez. context dependent. If available, distributed energy options Agustín Irizarry-Rivera ([email protected]) is would bring about not only local socioeconomic develop- with the University of Puerto Rico-Mayaguez. ment but also a new “supporting” role for the central, large Rafael Cintrón ([email protected]) is with the Uni- power plants and a new “service provider” business model versity of Puerto Rico-Mayaguez. for utilities. These changes will require new procedures for

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