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UTAH’S ONE-STOP-SHOP FOR SOLAR INFORMATIONSolar energy is here to stay: more U.S. consumers and businesses are investing in solar energy than everbefore. The US has over 22,700 MW of cumulative installed solar electric capacity, which is enough topower more than 4.6 million average American homes!SolarSimplified.org provides comprehensive solar information and tools for homeowners, businesses,contractors, local governments, and utilities to help expand Utah’s solar market and streamline the solarinstallation process.SALT LAKE SOLAR MAPUse the Solar Map to review your roof’s solar potentialSOLAR-FRIENDLY ZONING TOOLBOXSOLAR ZONINGGUIDELINESSOLAR-READYDEVELOPMENTMODEL ZONINGORDINANCERESOURCES FORZONING OFFICIALSReview best practices for solar zoning and planningRETURN ON INVESTMENT CALCULATOREstimate your return on investment with solarSTREAMLINED PERMITTING TOOLBOXSave time and money with the model expeditedsolar permit for UtahSolar Simplified was made possible with support from the U.S. Department of Energy SunShot Initiative's Rooftop Solar Challenge and the Wasatch Solar Challenge a partnership of Utah Clean Energy, Salt Lake City Corporation, Salt Lake County, West Valley City, Midvale, Summit County, and Park City. Utah Clean Energy developed all website content and the solar mapping analysis was conducted by GIS Analysts at Salt Lake City's Information Management Services Division and the UtahAutomated Geographic Reference Center (AGRC), with support from Salt Lake County's GIS division. Partners would like to give a special thanks to all of the involvedpartners and organizations for their support and contributions to the development of the website.
SOLAR AND STORAGEFOR ENERGY ANDRESILIENCYA guide for considerationUtah Clean EnergyWith support from:U.S. Department ofEnergy SunShot Initiative
SOLAR AND STORAGE FOR ENERGY AND RESILIENCY:A guide for considerationUtah Clean Energy, March 2016Table of ContentsINTRODUCTION .2CONSIDERATIONS FOR SOLAR AND STORAGE OR STORAGE-READY SYSTEMS .3TECHNICAL OPTIONS .4Solar Panels . 4Batteries. 4Charge Controllers . 5Inverters. 5SOLAR, STORAGE AND MICROGRIDS .7IMPLEMENTATION MODELS .8CASE STUDIES .9BARRIERS TO IMPLEMENTATION . 10APPENDIX A – Battery Types and Specifications . 11ADDITIONAL RESOURCES . 12Acknowledgement:The information, data, or work presented herein was funded in part by the Office of Energy Efficiency andRenewable Energy (EERE), U.S. Department of Energy, under Award Number DE-EE0006903.Disclaimer:The information, data, or work presented herein was funded in part 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 ofany information, apparatus, product, or process disclosed, or represents that its use would not infringe privatelyowned 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 favoringby the United States Government or any agency thereof. The views and opinions of authors expressed herein do notnecessarily state or reflect those of the United States Government or any agency thereof.Cover Photo Source: Salt Lake City Public Safety Building, Utah Adventure Journal, November 2015 hot-in-here .Page 1
SOLAR AND STORAGE FOR ENERGY AND RESILIENCY:A guide for considerationUtah Clean Energy, March 2016INTRODUCTIONThe growing frequency of extreme weather eventsand the very real threat of a significant earthquakein Utah drives the need for resilient backup powersystems. A self-generation power systemcomprised of solar photovoltaics coupled withbattery storage not only provides robust backuppower in the event of an emergency but also helpsmanage day-to-day energy usage. The versatilityand scalability of solar and storage and the abilityto combine a solar and storage system withtraditional backup generators makes solar andstorage an ideal solution for critical facilities thatrequire uninterrupted power supply such ashospitals, communication centers, radio stations,and community emergency shelters.A 330 kilowatt solar installation at the Natural History Museumof Utah. Utah’s solar capacity has grown rapidly in recent years.Retrofitting existing solar installations with battery storage canprovide resilient backup power in the event of a grid outage.1The cost to install solar has fallen about 75% since 2006,2 and solar installations are an increasinglypopular way to save money on utility bills. Battery storage costs have undergone similar price declines,falling by more than 50% since 2010, making solar with storage an increasingly viable solution for energymanagement in addition to emergency power.3 Future cost declines are expected to make commercialand industrial use of batteries for energy storage a cost-effective choice in certain markets within 3-5years, amplifying the advantages of solar energy and making solar and storage systems an attractiveeconomic offering in these markets.4As the solar market continues to grow in Utah, planning for storage by building storage-ready projectsopens the door for future cost savings. Understanding best practices for solar and storage systems willprepare facilities to incorporate solar and storage into new construction, scheduled renovations, or evenretrofits as storage costs continue to fall and technology improves.As you consider solar for your facility, this guide will help you understand how you can incorporatestorage into your project or make your project ‘storage-ready’ such that storage can be incorporatedcost-effectively in the future.1Utah Natural History Museum, https://newsdesk.nhmu.utah.edu/?q media/572 .GTM Research & Solar Energy Industries Association, U.S. Solar Market Insight 2015 Year-in-Review, March 2016. try-data .3 Moody’s Investor Service, “Declining battery prices could lead to commercial and industrial customer adoption in 3-5 years,” Sept2015 ial--PR 335274 .4 Ibid.2Page 2
SOLAR AND STORAGE FOR ENERGY AND RESILIENCY:A guide for considerationUtah Clean Energy, March 2016CONSIDERATIONS FOR SOLAR AND STORAGE OR STORAGE-READY SYSTEMS1. Determine your backup power goals:Solar and storage systems can be used to provide backup power for key critical loads, to providepower to an entire facility, or to provide supplementary power to extend the life of a backupgenerator. Decisions about battery technologies will be guided by your backup power goals2. Isolate critical loads on the same circuit:In order for solar and storage to provide power to critical loads in the event of a grid failure, thosecritical loads must be isolated on the same circuit. Isolating critical loads during construction orrenovation will prepare your facility to add solar and storage at a later date.3. When installing solar, choose a battery-ready solar inverterExisting solar installations can be retrofitted with battery storage more easily if they includeinverters that have the additional functionalities required to integrate battery storage. For moreinformation, refer to the Technical Options section below.4. Identify a location for the batteries which is of sufficient size and well ventilatedBatteries must be located onsite and must be directly connected to the solar installation. The sizeof the batteries will depend on the battery technology and the anticipated power needs of thebuilding. Electrical code requirements for batteries address safety concerns and require batteriesto be kept on appropriate racking in a well ventilated location.5 Anticipate the location of batterystorage and make accommodations during construction or renovations to prepare for the additionof storage.5. Refer to Clean Energy Group’s “Solar Storage Project Checklist,” which is designed to helpbuilding owners and developers assess whether solar and storage battery systems make sense fortheir buildings.65National Fire Protection Association National Electric Code 70, Article 480 Storage Batteries formation-pages?mode code&code 70 .6 Clean Energy Group, “Solar Storage Project Checklist,” solar-storage-projectchecklist/ .Page 3
SOLAR AND STORAGE FOR ENERGY AND RESILIENCY:A guide for considerationUtah Clean Energy, March 2016TECHNICAL OPTIONSSolar PanelsSolar panels provide power for a solar and storagesystem. Solar panels generate direct current (DC)power which must be converted to alternating current(AC) power to provide usable power for a building.Solar panels can be located on rooftops, carports,other structures, or even stand alone in open areas.BatteriesThere are several factors to consider when selecting abattery for a solar and storage system, including cost,energy density, expected lifespan, and safety. Allbatteries store DC power. Lead acid batteries are the oldest rechargeablebattery technology and are commonly found inautomobile engines. Whereas car batteries aredesigned to remain near full charge, lead acidbatteries designed for storage are able to bedischarged to 45% - 75% of their rated capacity sothat they can withstand repeated charging anddischarging. They have a low energy density, thusoccupying more space, and have a shorter lifespanthan lithium ion batteries. Lithium ion batteries are commonly used inlaptops and electric vehicles. They have a highenergy density thus making them lighter andsmaller. There are several types of lithium ionbatteries currently on the market, each made froma different lithium compound. Lithium ion batterieshave a longer lifespan than lead acid batteriesbecause they can be charged and discharged morefrequently. Proper installation, maintenance, anduse of lithium ion batteries is important to avoidoverheating, which can create a fire hazard.787Figure 1: The cost of solar energy has fallen more than 75%since 2006.7Figure 2: The cost of lithium ion batteries is expected to declinerapidly.8Solar Energy Industries Association Q2 2015 Solar Market Insight Fact Sheet, trydata .8 Rocky Mountain Institute, The Economics of Grid Defection, http://www.rmi.org/electricity grid defection .Page 4
SOLAR AND STORAGE FOR ENERGY AND RESILIENCY:A guide for considerationUtah Clean Energy, March 2016 Flow Batteries are a new type of rechargeable battery.Flow batteries consist of two liquid electrolytecompounds which are pumped across a membrane in onedirection to produce electricity and in the oppositedirection to charge the battery. Flow batteries are verysafe because the electrolytes are stored in separate tanks.They can be cycled 10,000 or more times, making themsuperior to lead acid and li-ion batteries. However, at thistime, their relatively high cost, low efficiency and lowenergy density is still a disadvantage.Advances in battery technology have broughtdown the cost and the size of batteries.9Recycling batteriesSome of the batteries used for storage contain toxic metals, and proper recycling is important to preventpollution and avoid environmental impacts. Lead acid batteries are recycled more than any other consumer product in the country. Disposal oflead acid batteries into landfills is illegal in most states.10 During the recycling process, lead can beeasily extracted and reused multiple times. Recycling centers must first remove combustiblematerial using a gas-fired thermal oxidizer and must mitigate pollution created by the process ofburning using scrubbers.11 Lithium ion batteries do not pose as significant an environmental concern but there are benefits torecycling them. Lithium ion batteries are composed of metals that have little or no recycling valuesuch a cobalt, nickel, and manganese, so the economics of recycling these batteries isn’t favorable.12However, as increasing numbers of lithium ion batteries enter the market, recycling of lithium ionbatteries is expected to be one of the main sources of future lithium supply.Charge ControllersA battery charge controller regulates the DC power produced by the solar array to prevent overchargingthe batteries. If the power input to the battery is not controlled it can result in damage to the batteriesand poses a safety hazard.InvertersSolar inverters are used to convert DC power produced by solar panels (or the DC power that is stored inbatteries) to AC power. A grid-connected solar and storage system must have a specific kind of inverterif it is to provide backup power in the event of a grid failure. A standard solar inverter is designed onlyfor converting DC power to AC power, and it will shut off in the event of a grid failure to protect linemanworking on the power lines.9PV Magazine, “Strong potential growth for storage, distributed generation and microgrids,” November 28 2012, ration-andmicrogrids 100009373/#ixzz44M7zdxJ8 .10 Waste Management World, “The Lithium Battery Recycling Challenge,” battery-recycling-challenge11 Battery University, “How to Recycle Batteries,” ng batteries 12 Waste Management World Op. Cit.Page 5
SOLAR AND STORAGE FOR ENERGY AND RESILIENCY:A guide for considerationUtah Clean Energy, March 2016In order for a solar and storage project to function both on and off the grid, the inverter must be able toprovide several functions. It must be able to monitor and communicate grid status, convert DCelectricity produced by solar panels to AC electricity, provide DC electricity to charge the battery,convert DC electricity stored in the battery to AC electricity for onsite use, and curtail power productionfrom the solar panels as needed to prevent damaging the battery Dual inverters are used in a DC-coupled solar and storage system and can accomplish all thesefunctions with a single inverter. A DC-coupled battery stores the DC power produced by solar panelswithout conversion and can also convert the power to AC for use in a building. Some dual inverters,known as Grid Forming Inverters, can also regulate voltage and frequency when the solar andstorage system is isolated from the grid. When installing a solar project, choosing a Dual Inverter orGrid Forming Inverter for the solar installation will allow for the future addition of storage at a lowercost. See Figure 3, below. Grid-tied inverters are used for grid-tied solar systems, and cannot provide islanding or backupfunctionality. Grid-tied inverters can be used to convert DC battery power to AC power for use inhomes or buildings as long as they remain grid connected. Stand-alone inverters are used for off-grid applications. These convert the DC power from the solarpanels and battery to AC power for use in homes or buildings that are not connected to the grid.An existing solar installation that does not have a Dual Inverter must be retrofitted to accommodatestorage by either replacing the existing inverter with a Dual Inverter or adding AC-coupled batteries. ACcoupled batteries store power after it has been converted to AC power by a standard solar inverter. Asecond battery inverter is required to convert the AC power back to DC in order to charge the battery,and to reverse the conversion when the battery power is needed to charge the building.13Figure 3: DC-Coupled Solar and Storage SystemA single battery inverter converts energy to charge batteries andpower the building.1313Figure 4: AC-Coupled Solar and Storage SystemA grid-tied inverter converts DC energy to AC energy. A secondbattery inverter converts AC power to DC to charge thebattery.13Source: Clean Energy Group, Solar Storage 101: An Introductory Guide to Resilient Solar Power Systems” nt-solar-power-systems/ .Page 6
SOLAR AND STORAGE FOR ENERGY AND RESILIENCY:A guide for considerationUtah Clean Energy, March 2016While this configuration is necessary to retrofit a grid-tied inverter with storage, an AC-coupled systemis less efficient than a DC-coupled system. For this reason, it is recommended that all inverter optionsare evaluated when installing solar. If battery storage capability is desired in the future then a storageready Dual Inverter is likely more cost effective in the long term.SOLAR, STORAGE AND MICROGRIDSIf protecting a facility from grid outagesis a priority and an objective, thenhaving a system that can isolate fromthe grid and operate autonomously iscritical. A microgrid is an energy systemof interconnected loads that consists ofone or more form of distributedgeneration and may also include energystorage that can function whileconnected to the grid and can alsofunction during grid outages byproviding resiliency benefits/emergencypower.14 Microgrids can be utilized topower critical loads on a single circuit, ina single building, or across an entirecampus. A microgrid can act as a singlecontrollable entity and can operate ineither grid-connected or islanded mode.15Figure 5: A microgrid is scalable to serve a single customer or alarger section of the distribution system.16Solar and storage can be integrated with generators to extend the life of existing backup power sources.In this case, to maintain generator reliability during a grid outage and to control system voltage andfrequency, at least one generator must run at all times, at a minimum of 30% of its rated capacity.17Additional generators can be ramped up or down in accordance with changes in load and solar energyoutput.Additional information about resilient solar hardware components and systems can be found in the NYSolar Smart DG Hub Hardware Factsheet.1814CUNY, NY Solar Smart DG Hub, “Glossary,” /SmartDGHubEmergencyPower/DG Hub Glossary.pdf .15 U.S. Department of Energy Office of Electricity Delivery & Energy Reliability on-s-energy-system .16 Ibid.17 CUNY, NY Solar Smart DG Hub, “Hardware Fact Sheet.” /SmartDGHubEmergencyPower/DecHardwareFactSheet.pdf .18 Ibid.Page 7
SOLAR AND STORAGE FOR ENERGY AND RESILIENCY:A guide for considerationUtah Clean Energy, March 2016IMPLEMENTATION MODELSSolar energy systems are an increasingly popular choice for electricity customers who want to reducetheir monthly utility bill and generate clean energy on site. When paired with battery storage, thebenefits of solar are multiplied. Solar and storage systems can provide a variety of services, fromresiliency benefits like emergency power to economic benefits like utility bill savings. The design of asolar and storage system will depend on the intended function (or functions) of the system. Solar andstorage systems can be broadly grouped into those designed to provide off-grid power and thosedesigned to provide grid-connected power. Grid-connected solar and storage installations can access awide variety of resiliency and economic benefits.Page 8
SOLAR AND STORAGE FOR ENERGY AND RESILIENCY:A guide for considerationUtah Clean Energy, March 2016CASE STUDIES1920OFF-GRID SOLAR AND STORAGE:The City of Houston purchased 17 solar powered shipping containersthat can be dispatched as needed in the event of an emergency, such asa hurricane, that disrupts the power grid. The containers function asmobile microgrids that can be used to provide emergency power forcharging critical devices or keeping medications cool. During nonemergency times, the containers will be used to provide mobile powerfor the Houston Parks Department or for special events.19GRID-CONNECTED SOLAR AND STORAGE:Florida’s SunSmart Emergency Shelter program equipped more than100 public schools with solar storage microgrid systems that canpower lighting and electrical outlets at the schools if the grid isdisrupted by a storm. Each school can provide emergency shelter for100 – 500 people. During normal operations, the schools are able touse the solar panels to offset daily electricity usage and save 1,500 1,600 annually.2019Source: Houston Public Media, “Houston Gets Emergency Solar-Powered Generation Units,” April 18, 2011 d-generation-units/ .Photo: Examiner.com, “Woodrow Wilson Montessori School is into solar-powered energy,” September 3 2012, tessori-school-is-into-solar-powered-energy .20 Source: Clean Energy Group, “SunSmart Emergency Shelters Program,” ency-shelters-program/ Photo: Florida Solar Energy Center x.html .Page 9
SOLAR AND STORAGE FOR ENERGY AND RESILIENCY:A guide for considerationUtah Clean Energy, March 2016BARRIERS TO IMPLEMENTATIONAlthough solar and storage systems offer significant resiliency benefits, barriers remain that limitimplementation of solar and storage systems.1. Cost of storage:Although the cost of storage has fallen rapidly, solar and storage systems still entail a long paybackperiod in Utah. Projections indicate that the cost of solar and storage installations will continue tofall and solar systems with storage will be cost-competitive with grid power in some locations by2020.21 Facility managers who consider best practices for installing solar and storage (or buildingsolar and storage-ready) will be prepared to take advantage of the benefits of solar and storagewhen the technologies are cost-competitive.2. A value for ancillary benefits:Currently, Utah utilities do not offer payment for ancillary services that solar and storage couldprovide to the utility. Potential ancillary services include demand response and frequencyregulation services that reduce could reduce utility costs and create a more responsive and resilientgrid. Although Utah customers are not currently compensated for these services, new ratestructures could create additional value for solar and storage installations while also reducing utilitycosts for all customers.3. Lack of clarity in Federal Investment Tax CreditThe IRS does not explicitly list energy storage as an approved technology that is eligible for theFederal renewable energy tax credit. The IRS has requested feedback regarding the ITC and itsapplicability to storage and is projected to issue proposed regulations in spring 2017 and issue finalregulations in fall 2018.224. Low cost of electricity in UtahWithout compensation for ancillary services, the economic benefit of battery storage comes fromenergy and demand charge reductions. The relatively low cost of electricity in Utah creates a longpayback period for solar and storage installations in Utah. As the cost of battery technologiescontinues to fall, the value proposition for solar and storage systems will improve.21Rocky Mountain Institute, op. cit., P7Deloitte, “Financing Energy Storage with Tax Credits,” September 28, 2015 http://www2.deloitte.com/us/en/misc/search.html#qr investment%20tax%20credit .22Page 10
SOLAR AND STORAGE FOR ENERGY AND RESILIENCY:A guide for considerationUtah Clean Energy, March 2016APPENDIX A – Battery Types and SpecificationsThis table is adapted from the CUNY NY Solar Smart DG Hub, Resilient Photovoltaic (PV) Systems Hardware Factsheet, available dfSpecificationsBattery TypesLead AcidValve RegulatedUsageEnergy Density(Wh/kg)Lifetime cycles(80% depth ofdischarge)Efficiency (%)Resiliency, GridSupport, Peakloadshifting,Intermittentenergysmoothing, UPS30-50200-30023Lithium IonLithium keltitanatemanganesemanganese cobaltoxidecobaltaluminumoxideoxideResiliency, Grid Support, Peak load shifting, Intermittent energysmoothing, 00050030007000300-70010000 80-90%90-95%8-16hrs2-4hrsCost 150-300/kWh 400/kWhThermalRunaway Tempand Stability24Consideredthermally safeAdvantagesWell-known,reliabletechnology, canwithstand deepdischarges,relativelylowcost, ease ofmanufacturingRelatively lownumber of lifecycles and lowerenergy density270 CAmong thesafest typeofli-ionbatteryHigh energycycle lives23RedoxResiliency,GridSupport, Peak loadshifting, Intermittentenergy smoothing,UPS, Bulk powermanagement10-20Charge RateDisadvantagesFlow Batteries2-4hrs2-4hrs65-85%1-2hrs1-2hrs 428 240 2000/k 250750/kWh380/kWhWh300/kWh210 C150 CAmong250 CLess stable Leastthe safest Mediumthanstabletype of li- stabilitylithium ironionphosphatebatterydensity, able to withstand deep discharges, and longMore expensive than lead acid systems and may become thermallyunstable. Overheating or short circuits in Li-ion cells may causethermal run-away—a phenomenon where the internal heatgeneration in a battery increases faster than it can dissipate. Thisheat can damage or destroy the cells and is a potential source forfires. Electronic protection circuits are added to the battery pack toprevent thermal run-awayDepends on size ofthe tank and cellstack 680-800/kWhVerysafesincestorage of electrolyteis separate frompowergenerationunitWell suited for bulkstorage, long cyclelife, and easy to scaleup the amount ofenergy stored bysimply making thetanks largerRelatively high cost,low efficiency andlow energy density;highmaintenancewith pumps thatoftenleakandprecipitate outManaging the depth of discharge for lead acid batteries increases the lifespan of these batteriesBattery University, “Types of Lithium Ion,” http://batteryuniversity.com/learn/article/types of lithium ion , accessed on 15March 2016. Note that the battery technology is rapidly changing with their growth in the market.24Page 11
SOLAR AND STORAGE FOR ENERGY AND RESILIENCY:A guide for considerationUtah Clean Energy, March 2016ADDITIONAL RESOURCES1. Clean Energy Group. Solar Storage Project Checklist. January /Solar-Storage-Checklist.pdf2. Clean Energy Group. Solar Storage 101: An Introductory Guide to Resilient Power Systems. March2015. gy-Storage-101.pdf3. The City University of New York, Smart Distributed Generation Hub – Resilient Solar Project.Hardware Factsheet. October t.pdf4. The City University of New York, Smart Distributed Generation Hub – Resilient Solar Project. FinanceFactsheet – Economics and Finance of Solar Storage. September .pdf5. Houston Public Media, Houston gets Emergency Solar-powered Generation Units. April wered-generation-units/6. Clean Energy Group, SunSmart Emergency Shelters Program. ency-shelters-program/7. Clean Energy Group, Stafford Hills Solar Farm and Microgrid. 8. Green Mountain Power, Green Mountain Power to Offer Tesla Home Battery. May ery?feed d51ec270-a483-4f6c-a55e-8e5fbe2238c2About Utah Clean Energy: Utah Clean Energy is a non-profit, non-partisan public interest organizationpartnering to build the clean energy economy. We are committed to creating a future that ensures healthy,thriving communities for all, empowered and sustained by clean energy.About the SunShot Initiative: The U.S. Department of Energy SunShot Initiative is a collaborative nationaleffort that aggressively dri
Review best practices for solar zoning and planning solar permit for Utah SOLAR-FRIENDLY ZONING TOOLBOX SOLAR ZONING GUIDELINES MODEL ZONING ORDINANCE SOLAR-READY DEVELOPMENT RESOURCES FOR . 2 GTM Research & Solar Energy Industries Association, U.
