{"id":120,"date":"2023-11-16T20:27:15","date_gmt":"2023-11-16T20:27:15","guid":{"rendered":"https:\/\/terrascope2027.wpenginepowered.com\/?page_id=120"},"modified":"2023-12-01T01:23:28","modified_gmt":"2023-12-01T01:23:28","slug":"solar","status":"publish","type":"page","link":"https:\/\/terrascope2027.mit.edu\/?page_id=120","title":{"rendered":"Solar Energy Overview"},"content":{"rendered":"\n
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Solar Energy<\/p>\n<\/div><\/div>\n\n\n\n

Image: Unsplash. \u201cPhoto by Andreas G\u00fccklhorn on Unsplash.\u201d Unsplash.com<\/em>, 14 June 2017, unsplash.com\/photos\/photo-of-three-solar-panels-7razCd-RUGs. Accessed 21 Nov. 2023.<\/p>\n\n\n\n

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What is Solar Energy?<\/p>\n\n\n\n

Creating solar electricity is the process by which solar panels convert the sun\u2019s radiation into usable electrical current. These panels are made of photovoltaic cells, or the small electronic devices which actually perform this conversion. Different types of solar cells have different efficiencies, or different ratios of power output for a given solar radiation input.<\/p>\n\n\n\n

Why Solar?<\/h2>\n\n\n\n

Solar panels provide a promising solution considering the situational requirements for Puerto Rico.\u00a0Solar panels are also very weather-resistant, especially if installed properly. This makes them resilient during natural disasters, which are prevalent in Puerto Rico. They can typically withstand winds of up to 140 miles per hour, which is in the range of a category four hurricane1<\/sup>. Panels are also tested for safety in the event of being struck by hail or a falling object and must be deemed non-hazardous given reasonable impact pressure. The type of rack a solar system is mounted onto can also impact its weather resistance; typically, steel racks and mounting brackets are recommended for areas that are at risk for high wind speeds. Having secure steel brackets and weather-rated bolt systems can greatly increase the stability of any system. Solar panels themselves are highly waterproof and are usually developed with every effort to withstand weather events. Even so, it may be beneficial to ask contractors about weather insurance or repair plans in areas where weather conditions and debris are a strong concern.<\/p>\n\n\n\n

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Power Considerations<\/p>\n\n\n\n

The amount of power produced with solar energy is dependent on the solar panel itself. Solar energy is affected by the maximum power rating, which represents the maximum amount of power a device can hold without damaging itself, of a given solar panel and the efficiency of the panel itself.<\/p>\n\n\n\n

The amount of power produced with solar energy is also dependent on the geographic characteristics of the area the solar panel is located in. This specifically is related to the average peak solar hours of the geographic location2<\/sup>. A peak sun hour is when the sun\u2019s intensity reaches an average of 1,000 watts of photovoltaic power per square meter3<\/sup>. Specifically, the average peak solar hours are affected by the amount of sunlight that can reach the panels. The factors affecting the amount of sunlight that reaches the panels are quantified in the data table<\/a>. These considerations include the cloud amount (in %)4<\/sup> and tree cover of each municipality (in hectares) which both provide obstacles to the sun\u2019s rays, the grade or slope of the city which affects the angle of sunlight contact (greater angle results in less concentration of sunlight), and all-sky insolation clearness index5<\/sup>. This index represents the ratio of the total solar radiation at the Earth\u2019s surface to the insolation6<\/sup>, or exposure to the sun\u2019s rays, available at the top of the atmosphere7<\/sup>.<\/p>\n\n\n\n

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Batteries for Photovoltaic Systems<\/h2>\n\n\n\n

As of now, about three percent<\/em> of Puerto Rico\u2019s electricity is generated from renewable sources. Three-fifths <\/strong>of that portion is generated from solar photovoltaics <\/strong>(PV)8<\/sup>.<\/p>\n\n\n\n

Since hurricane Maria (2017) hit Puerto Rico, over 45,000 solar panels have been installed, and most of the recent installations include batteries, the majority of which are lithium-ion<\/strong>9<\/sup>.<\/strong><\/p>\n\n\n\n

Lithium-Ion Batteries<\/h3>\n\n\n\n

As of now, lithium-ion batteries holds more than 90% of the global battery market, despite not <\/em>being a very affordable battery typ10<\/sup>.<\/p>\n\n\n\n

Lithium-ion batteries have higher gravimetric energy densities (measurement of energy stored per unit mass of a substance) and <\/em>higher volumetric energy densities compared to most other batteries. Lithium-ion type batteries are also lighter. These batteries also have relatively long average lifespans, capable of lasting a minimum of 3,000 discharge\/charge cycles (the life cycle of a battery \u2013the number of times it is discharged and recharged before losing performance).\u00a0 Lithium-ion batteries are very efficient and would pair well with solar-powered microgrids\u2014systems that rely on a source of energy that varies over time (eg. amount of sunlight in a given day)11<\/sup>.<\/p>\n\n\n\n

Technology<\/strong><\/td>Specific Energy (Wh\/kg)<\/strong><\/td>Specific Power (W\/kg) <\/strong><\/td>Efficiency of Energy Storage (%)<\/strong><\/td>Service life (yrs) <\/strong><\/td><\/tr>
Lithium-ion batteries<\/em><\/td>75-250<\/em><\/td>150-315<\/em><\/td>85-95<\/em><\/td>5-15<\/em><\/td><\/tr>
Lead Acid Batteries<\/td>30-50<\/td>75-300<\/td>70-80<\/td>5-15<\/td><\/tr>
Sodium Sulfur Batteries<\/td>150-240<\/td>150-230<\/td>80-90<\/td>15<\/td><\/tr>
Nickel Metal Hybrid Batteries<\/td>70-100<\/td>200-300<\/td>70<\/td>5-10<\/td><\/tr><\/tbody><\/table>
Figure 1- This figure looks at the technical characteristics of five commonly used batteries technologies utilized in microgrid systems. Some of these characteristics include <\/em>specific power, <\/em><\/strong>the power-to-weight ratio that measures the performance of a power source, and\u00a0 <\/em>specific energy<\/em><\/strong>, energy per unit of mass. In all these metrics, lithium-ion batteries have the most desirable characteristics \u2013 relatively high specific energy, high specific power, high efficiency in energy storage, and the potential of many years of service<\/em>11<\/sup>.\u00a0<\/em><\/figcaption><\/figure>\n\n\n\n

Case Study<\/h3>\n\n\n\n

Martin Garc\u00eea Middle School (MGMS), a school in Toa Baja (a municipality on the northern coast of Puerto Rico) collaborated with Blue Planet Energy,<\/a> an energy storage company, to implement a PV-system with a subtype <\/em>of lithium-ion batteries: a lithium iron phosphate battery<\/strong>12<\/sup>.<\/p>\n\n\n\n

Lithium iron phosphate (LFP) batteries do not rely on rare minerals (such as neodymium and dysprosium which are critical elements used in many modern technologies and are very difficult to extract from the Earth\u2019s crust), and remain stable under extreme climate conditions \u2013such as Puerto Rico\u2019s typical hot climate\u2013 thus LFP batteries can maintain a long lifecycle with little to no maintenance requirements13<\/sup>.\u00a0<\/p>\n\n\n\n

With such a battery in place, MGMS was able to act as the community\u2019s shelter for electricity during extreme weather periods. With clean energy backed up by a battery with a total capacity of 112 kWh, MGMS had kitchens available for use year-round to serve food for lower-income families. Students at the school were no longer missing out on class time due to the frequent outages in the region, which average around 30 outages per year12<\/sup>.<\/p>\n\n\n\n

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References<\/summary>\n
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  1. \u201cCan Solar Panels Withstand Hail and Hurricanes?\u201d\u00a0EnergySage<\/em>, 8 June 2017, www.energysage.com\/solar\/solar-panels-hail-hurricanes\/. Accessed 29 Nov. 2023.\u00a0<\/li>\n\n\n\n
  2. \u00a0\u201cHow to Calculate Solar Panel Output? (+ Kwh Calculator).\u201d The Green Watt, 21 Feb. 2023, http:\/\/thegreenwatt.com\/how-to-calculate-solar-panel-output\/. Accessed 28 Nov. 2023.<\/li>\n\n\n\n
  3. \u00a0Kielar, Hanna. \u201cGuide to Peak Sun Hours.\u201d GreenLancer<\/em>, GreenLancer, 29 Mar. 2023, www.greenlancer.com\/post\/peak-sun-hours. Accessed 28 Nov. 2023.<\/li>\n\n\n\n
  4. \u00a0\u201c2022 Deforestation Statistics for Puerto Rico.\u201d Deforestation Statistics for Puerto Rico, Mongabay, https:\/\/rainforests.mongabay.com\/deforestation\/archive\/Puerto_Rico.htm. Accessed 28 Nov. 2023.<\/li>\n\n\n\n
  5. \u00a0\u201cPower.\u201d Prediction of Worldwide Energy Resource (POWER) | Data Access Viewer Enhanced, NASA, https:\/\/power.larc.nasa.gov\/beta\/data-access-viewer\/. Accessed 28 Nov. 2023.<\/li>\n\n\n\n
  6. \u00a0\u201cInsolation.\u201d Insolation – an Overview | ScienceDirect Topics<\/em>, https:\/\/www.sciencedirect.com\/topics\/earth-and-planetary-sciences\/insolation. Accessed 28 Nov. 2023.\u00a0<\/li>\n\n\n\n
  7. \u00a0\u201cCenter for Satellite Applications and Research – NOAA \/ NESDIS \/ Star.\u201d NOAA \/ NESDIS \/ STAR Website<\/em>, www.star.nesdis.noaa.gov\/smcd\/emb\/radiation\/solar_resource_definitions.php. Accessed 28 Nov. 2023.\u00a0<\/li>\n\n\n\n
  8. \u00a0\u201cPuerto Rico Profile.\u201d Eia.gov, 2022, www.eia.gov\/state\/print.php?sid=RQ#:~:text=For%20fiscal%20year%202022%20(July%202021%E2%80%94June%202022)%20about,and%20landfill%20gas%2Dfueled%20facilities. Accessed 28 Nov. 2023.<\/li>\n\n\n\n
  9. \u201cMicrogrids in Puerto Rico Keep Rural Communities Connected | Article | EESI.\u201d Eesi.org, 2023, www.eesi.org\/articles\/view\/microgrids-in-puerto-rico-keep-rural-communities-connected. Accessed 21 Nov. 2023.<\/li>\n\n\n\n
  10. \u201cFact Sheet | Energy Storage (2019) | White Papers | EESI.\u201d Eesi.org, 2019, www.eesi.org\/papers\/view\/energy-storage-2019#:~:text=Lithium%2Dion%20batteries%20are%20by,energy%20density%20and%20are%20lightweight. Accessed 21 Nov. 2023.<\/li>\n\n\n\n
  11. \u00a0Zarate-Perez, Eliseo, et al. \u201cBattery Energy Storage Performance in Microgrids: A Scientific Mapping Perspective.\u201d Energy Reports, vol. 8, 1 Nov. 2022, pp. 259\u2013268, www.sciencedirect.com\/science\/article\/pii\/S2352484722012598#b35, https:\/\/doi.org\/10.1016\/j.egyr.2022.06.116. Accessed 28 Nov. 2023.<\/li>\n\n\n\n
  12. \u00a0\u201cBlue Planet Energy Creates Resilience Hubs at Puerto Rican Schools.\u201d SolRenew<\/em>, solrenew.com\/blue-planet-energy-battery-storage\/. Accessed 21 Nov. 2023.\u00a0<\/li>\n\n\n\n
  13. \u00a0Critical Minerals \u2013 Topics – IEA. \u201cCritical Minerals \u2013 Topics – IEA.\u201d IEA, 2023, www.iea.org\/topics\/critical-minerals. Accessed 21 Nov. 2023.<\/li>\n<\/ol>\n<\/details>\n","protected":false},"excerpt":{"rendered":"

    Image: Unsplash. \u201cPhoto by Andreas G\u00fccklhorn on Unsplash.\u201d Unsplash.com, 14 June 2017, unsplash.com\/photos\/photo-of-three-solar-panels-7razCd-RUGs. Accessed 21 Nov. 2023. What is Solar Energy? Creating solar electricity is the process by which solar panels convert the sun\u2019s radiation into usable electrical current. These panels are made of photovoltaic cells, or the small electronic devices which actually perform this […]<\/p>\n","protected":false},"author":8,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":"[]"},"class_list":["post-120","page","type-page","status-publish","hentry"],"featured_image_src":null,"featured_image_src_square":null,"_links":{"self":[{"href":"https:\/\/terrascope2027.mit.edu\/index.php?rest_route=\/wp\/v2\/pages\/120","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/terrascope2027.mit.edu\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/terrascope2027.mit.edu\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/terrascope2027.mit.edu\/index.php?rest_route=\/wp\/v2\/users\/8"}],"replies":[{"embeddable":true,"href":"https:\/\/terrascope2027.mit.edu\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=120"}],"version-history":[{"count":0,"href":"https:\/\/terrascope2027.mit.edu\/index.php?rest_route=\/wp\/v2\/pages\/120\/revisions"}],"wp:attachment":[{"href":"https:\/\/terrascope2027.mit.edu\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=120"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}