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Home My WebLink About2017 Energy Storage Published ArticleAn Alaska case study: Energy storage technologies Jeremy VanderMeer, Marc Mueller-Stoffels, and Erin Whitney Citation: Journal of Renewable and Sustainable Energy 9, 061708 (2017); View online: https://doi.org/10.1063/1.4986580 View Table of Contents: http://aip.scitation.org/toc/rse/9/6 Published by the American Institute of Physics Articles you may be interested in Preface: Technology and cost reviews for renewable energy in Alaska: Sharing our experience and know-how Journal of Renewable and Sustainable Energy 9, 061501 (2017); 10.1063/1.5017516 An Alaska case study: Solar photovoltaic technology in remote microgrids Journal of Renewable and Sustainable Energy 9, 061704 (2017); 10.1063/1.4986577 Wind power project size and component costs: An Alaska case study Journal of Renewable and Sustainable Energy 9, 061703 (2017); 10.1063/1.4986579 An Alaska case study: Diesel generator technologies Journal of Renewable and Sustainable Energy 9, 061701 (2017); 10.1063/1.4986585 An Alaska case study: Organic Rankine cycle technology Journal of Renewable and Sustainable Energy 9, 061707 (2017); 10.1063/1.4986583 An Alaska case study: Biomass technology Journal of Renewable and Sustainable Energy 9, 061705 (2017); 10.1063/1.4986578 An Alaska case study: Energy storage technologies Jeremy VanderMeer,Marc Mueller-Stoffels,and Erin Whitney Alaska Center for Energy and Power, University of Alaska Fairbanks, P.O. Box 755910, Fairbanks, Alaska 99775-5910, USA (Received 6 June 2017; accepted 14 September 2017; published online 21 December 2017) In the analysis of energy storage systems (ESSs) in Alaska, the most signiﬁcant trend in the data considered is the increased variance in costs with time. Thus, more options are now available for ESS with “low cost per kW/high cost per kWh” and vice versa, indicating a greater variety of specialized ESS for targeted applications. The data analyzed do not show any difference in the cost of energy storage in Alaska compared to such costs in the rest of the nation or world. Alaska has had relatively few energy storage technology failures, and most that occurred were caused by improper operation. It is often difﬁcult to justify energy storage economically based on fuel savings alone. Signiﬁcant work remains to quantify other possible cost savings afforded by energy storage, such as reduced fuel consumption and stress on a diesel generator by smoothing out the load. The lack of standardization and quantiﬁcation of costs and beneﬁts is the main barrier to determining the economic potential for implementation of energy storage in Alaska. In addition, communities in Alaska often wish to avoid ESS that uses hazardous materials since each community will eventually have to deal with disposal issues.Published by AIP Publishing.https://doi.org/10.1063/1.4986580 INTRODUCTION Since the discovery of electricity, humans have sought effective methods to store that energy for use on demand. Energy storage systems (ESSs) provide a technological approach to managing power supply to create a more resilient energy infrastructure. In this paper, ESS refers to systems that store electrical energy (either chemical, mechanical, or electrical) and later return it to the grid. There are 514 grid-connected ESS installations in the United States, totaling over 24GW of power capacity. According to the U.S. Department of Energy (U.S. DOE, 2017), 159 new ESS projects have been announced or contracted, which will increase grid-connected energy storage by 7.2GW. Remote microgrids are not connected to a larger electrical grid. This means that they must generate all electricity that is consumed within the grid. In Alaska, remote microgrids are small, which means there are relatively few electrical loads in a system and thus a high level of stochas- ticity in the total microgrid electrical load. Adding high penetrations of stochastic renewable energy makes it increasingly difﬁcult to match generation with demand. Energy storage systems offer an attractive solution to this challenge. Alaska currently has eight grid-connected ESS instal- lations totaling 61MW, with one project totaling 0.32MW currently contracted (U.S. DOE, 2017). Energy storage systems can be divided into the energy storage unit and the power condition- ing system, as shown in Fig.1. The energy storage unit determines the amount of energy that can be stored, or the energy capacity, in kilowatt-hours. The power conditioning system is the inter- face between the grid and the energy storage unit and controls charging and discharging. Thus, the power conditioning system is largely responsible for the power in kilowatts of ESS. This review of ESS in Alaska is a result of Alaska Senate Bill (SB) 138. In this bill, the Alaska State Legislature created an uncodiﬁed section of law entitled “Plan and Recommendations to the Legislature on Infrastructure Needed to Deliver Affordable Energy of the State to Areas That Do Not Have Direct Access to a [proposed] North Slope Natural Gas Pipeline.” To support the Alaska Energy Authority (AEA) in its development of an affordable energy strategy for Alaska, the Alaska Center for Energy and Power (ACEP) contracted with AEA to document technology development needs speciﬁc to the state with regard to renewable 1941-7012/2017/9(6)/061708/18/$30.00 Published by AIP Publishing.9, 061708-1 JOURNAL OF RENEWABLE AND SUSTAINABLE ENERGY 9, 061708 (2017) and sustainable energy technologies. The intention was to determine what targeted, energy tech- nology development solutions could be implemented in Alaska to make energy more affordable in the Alaska Affordable Energy Study area. While the focus was on technology research solu- tions, other factors such as logistics, labor, and training were also addressed. Drafts of technol- ogy reviews were vetted by expert roundtables in late February and early March 2016. These reviews are not meant to be exhaustive discussions of energy technologies in Alaska or proper designs for each technology, and they should not be used as guides for the choice and installation of speciﬁc systems. As such, not all possible issues with power production and each technology are addressed. Data for each technology were collected from surveys and pub- lically available databases. Only completed projects, or projects with clearly reported data, were included in each technology analysis. These distinctions and descriptions of data sources are included in each technology review. METHODS Deployment of ESS is still nascent in Alaska, with a few exceptions. Thus, the dataset developed from AEA Renewable Energy Fund (REF) applications has been supplemented with data from the U.S. DOE Global Energy Storage Database. The U.S. DOE database captures installation data worldwide from Sandia National Laboratory’s energy storage reports (several editions) and data collected by ACEP through personal communication with energy storage developers and utilities. Data sources are detailed in Appendix A. Lead-acid, advanced lead-acid (Xtreme Power), lithium-ion, ﬂow (vanadium redox and zinc-bromine), nickel-based (nickel cadmium) batteries, ﬂywheels, compressed air, and closed- loop pumped hydro and open-loop pumped hydro energy storage are the technologies repre- sented by the available data. Demonstration projects were removed from this paper since many of them had inexplicably high costs. Note that none of the ﬂow battery projects reported here are currently operational, includ- ing the vanadium redox ﬂow battery that Kotzebue had received a quote on from VRB before the company went out of business, the zinc-bromine ﬂow battery purchased by Kotzebue from Premium Power, which was decommissioned and two other batteries that are contracted/under construction. We are not certain, therefore, that the prices presented accurately reﬂect the cost of functioning systems. All costs have been converted to 2015 dollars based on the Consumer Price Index (CPI) (U.S. Bureau of Labor Statistics, 2016). DISCUSSION Capital costs by power and energy capacity Energy storage systems generally consist of the actual storage device (e.g., a battery or ﬂy- wheel), which deﬁnes the energy capacity and theoretical maximum power available, and power conversion systems, which determine the actual maximum power available for both charging and discharging. As the two systems—storage device and power conversion system—are sepa- rate units selected depending on a particular application, it makes sense to examine the capital cost of systems in relation to both energy storage capacity and power capacity, referred to herein as the Capacity and Power of an ESS. In the rest of this review, capital costs will be FIG. 1. A basic energy storage system contains an energy storage unit and a power conditioning system; in this case, the energy storage unit operates with a DC voltage and an inverter is used to convert the DC power into AC on the distribution or transmission grid. The inverter will also need to be able to act as a rectiﬁer and convert AC power into DC to charge the energy storage unit. 061708-2 VanderMeer, Mueller-Stoffels, and Whitney J. Renewable Sustainable Energy 9, 061708 (2017) referred to as CAPEX, which denotes the capital expenditures required to acquire the energy storage system, as opposed to later operating expenses (OPEX). Figures 2 and 3 show the cost per capacity ($/kWh) and rated power ($/kW) plotted against capacity and rated power for global and Alaska projects. The variation in CAPEX/capacity and CAPEX/power is wide, and no trends are obvious, both overall and within particular technologies. The wide variation in CAPEX/capacity and CAPEX/power can be partly explained by differ- ences in the infrastructure included in CAPEX. For example, one project simply involved replac- ing the batteries in an existing installation, while other projects required various infrastructures such as a building and interconnection. Cost breakdowns were not given for most of the data, and it was not always clear what was included in CAPEX. All costs from REF applications for projects in Alaska (labeled AK on the plots) include transport, hardware, and installation. The variation can also be partly explained by the ratio of capacity to rated power (or the duration in hours). CAPEX/power tends to be higher for ESS with a longer duration, while CAPEX/capacity tends to be lower. The plots of CAPEX/capacity and CAPEX/power versus duration can be seen in Figs.6 to 9 in Appendix A. The costs presented in Figs.2 and 3 are best understood in the context of what each data point represents. A short description of the different projects presented in these ﬁgures is given in Appendix B and helps to explain the variation seen in costs. Note that the cost data on ﬂow batteries are for installations that are not currently operational. FIG. 2. The plot of CAPEX/capacity versus capacity for non-hydro energy storage. The inset shows a scaled view of the y-axis for easier viewing of lower CAPEX/capacity values. Data are shown for both global and Alaska installations. Flywheels tend to be more expensive per capacity (kWh) than other forms of energy storage; they tend to be cheaper per rated power (see Fig.3). FIG. 3. The plot of CAPEX/power versus power for non-hydro energy storage. Data are shown for both global and Alaska installations. 061708-3 VanderMeer, Mueller-Stoffels, and Whitney J. Renewable Sustainable Energy 9, 061708 (2017) Table I shows mean values of CAPEX/power and CAPEX/capacity for global and Alaska data. Similar to Figs.2 and 3, these values are best understood in the context of the projects they represent. See Appendix B for an overview of the different projects. Operation and maintenance ($/kW) Data for global and Alaska operation and maintenance (O&M) costs were minimal. A report by Sandia (Schoenung and Hassanzahl, 2003) gives the estimates shown in Table II. The O&M values given for ﬂow batteries are low, based on the experience and knowledge of the authors. Expected life and efficiency The energy efﬁciency and expected number of cycles before replacement/overhaul, from a 2011 Sandia report (Schoenung, 2011), are shown in Table III. Electro-mechanical systems, like pumped hydro and ﬂywheels, typically can be overhauled at minimal cost, while electro- chemical systems typically need to be replaced. The replacement period in years is used for levelized cost of energy (LCOE) and levelized cost per cycle power (LCCP) calculations and corresponds to the end of the cycle life. The performance metrics listed for ﬂow batteries are much higher than what the authors have experienced or are aware of in actual installations. The expected efﬁciency of an ESS is highly technology and use dependent. Table III shows average values for the round trip efﬁciency of different ESS technologies. For a given ESS, the TABLE I. Mean CAPEX/power and CAPEX/capacity for global and Alaska data. Global Alaska Technology Mean CAPEX/power ($/kW) Mean CAPEX/capacity ($/kWh) Mean CAPEX/power ($/kW) Mean CAPEX/capacity ($/kWh) Flow battery 8401 2444 3758 1089 Lead-acid battery 1785 1785 3472 2480 Lead-acid battery (advanced) 1408 5634 1328 5311 Lithium-ion battery 2292 2115 2172 7797 Nickel-based battery 1668 6674 979 2650 Closed-loop pumped hydro 1438 141 Open-loop pumped hydro 995 77 Compressed air energy storage 1120 80 Flywheel 3026 261978 TABLE II. O&M costs for different energy storage technologies, from Sandia’s 2003 report (Schoenung and Hassanzahl, 2003); O&M is reported in $/kWyr. Note: Costs have been increased by 30% to update them to 2015 dollars based on the CPI. The costs for power generation are not as straightforward as the costs for energy storage, as O&M is inﬂuenced by more variables. Name O&M [$/(kWyr)] Lead-acid battery (ﬂooded cell)19.5 Lead-acid battery (advanced)6.5 Lithium-ion battery 32.5 Nickel cadmium battery 32.5 Zinc bromine ﬂow battery 26 Vanadium redox ﬂow battery 26 Flywheels (high speed)6.5 Compressed air energy storage (surface) 13 Pumped hydro 3.25 061708-4 VanderMeer, Mueller-Stoffels, and Whitney J. Renewable Sustainable Energy 9, 061708 (2017) round trip efﬁciency will vary depending on how it is operated. For example, a ﬂy wheel’s efﬁ- ciency will vary depending on its rotational speed (amount of stored energy) and its power out- put or input. The length of time between charge and discharge will also affect round trip efﬁ- ciency due to the rotational losses (friction) in the ﬂywheel. Thus, the method of operation will have a signiﬁcant impact on the round trip efﬁciency of a ﬂywheel. This is also true to varying degrees for other ESS technologies. See the section on Conditions for the Greatest Efﬁciency for a discussion of the different types of energy losses in an ESS. Capacity factor The capacity factor for energy storage technology is not applicable. Diesel offset General uses for ESS are peak shifting (charging during low load/high generation events and discharging during high load/low generation events), power quality support (balancing high ramp rates in the load or renewable generation), and supplying spinning reserve capacity (SRC: the ability to meet suddenly rising demand or replace suddenly dropping generation; this allows smaller generators or no diesel generators to run online). Peak shifting generally saves diesel by increasing the utilization of renewable energy. Providing power quality support reduces TABLE III. Performance characteristics of ESS technologies (Schoenung, 2011;Schoenung and Hassanzahl, 2003;Divya and Ostergaard, 2009;Butler et al., 2000;Viswanathan et al., 2013). Technology Round trip efficiency (%) Depth of discharge (%) Cycle life Replacement period (yr) Lead-acid battery (ﬂooded cell) 75 50 2000 6 Lead-acid battery (advanced) 80 50 2000 6 Lithium-ion battery 85 80 4000 10 Nickel cadmium battery 65 100 3000 10 Zinc bromine ﬂow battery 70 100 3000 8 Vanadium redox ﬂow battery 65 100 5000 10 Flywheels (high speed) 95 100 25000 20 Compressed air energy storage (surface) 70 100 25000 30 Pumped hydro 85 100 25000 30 FIG. 4. LCOE for energy storage applications. The inset shows a scaled view of the y-axis for easier viewing of lower LCOE values. LCOE values for energy storage only show the energy throughput of the storage device and not the increase in energy production from cheaper sources, such as renewable energy, that it enables. The LCOE and LCCP of energy stor- age must be understood in terms of how they affect the cost of energy in the entire system. 061708-5 VanderMeer, Mueller-Stoffels, and Whitney J. Renewable Sustainable Energy 9, 061708 (2017) stress on diesel generators, which increases their lifespan and efﬁciency. Providing SRC saves diesel by allowing a smaller or no diesel generator to run online, enabling a much higher use of renewable energy. Schaede et al.(2015)provided an example of possible diesel savings with energy storage. They modelled Nome’s grid with 959kW/58kWh ﬂywheel energy storage supplying SRC. Nome’s grid has an average load of 4MW and an installed wind power capacity of 2.7MW. The ﬂywheels supplied SRC (as well as load leveling), which allowed smaller diesels to run online and let wind power supply a higher fraction of the load when wind power was available, reducing diesel consumption. The energy storage reduced diesel consumption by 850gal/week during periods with high levels of wind power and by 450gal/week during periods with low levels of wind power. Cost per kWh For energy storage, the levelized cost of energy (LCOE) is deﬁned as the levelized cost of storing energy ($/kWh stored). However, this metric does not give the whole picture since it does not take into account the power at which energy storage is able to charge and discharge. A second metric called levelized cost per cycle power (LCCP) is used for this. The LCCP, which provides levelized cost per cycle per kW [$/(cyclekW)], does not take into account the duration of the discharge (charge) and is more relevant for applications, such as power quality, that need high power and not necessarily long duration. The equations for LCOE and LCCP are given in Appendix C. Both LCOE and LCCP were calculated assuming an inﬂation rate of 2%, an interest rate of 5%, and the typical depth of FIG. 5. LCCP for energy storage applications. TABLE IV. Mean LCOE and LCCP for global and Alaska data. Note that all data used in this paper for ﬂow batteries are from systems that are not currently operational. Global Alaska Technology Mean LCOE ($/kWh) Mean LCCP [$/(cyclekW)] Mean LCOE ($/kWh) Mean LCCP [$/(cyclekW)] Flow battery 1.0 2.2 0.45 1.0 Lead-acid battery 2.8 1.1 3.8 2.1 Lead-acid battery (advanced) 8.5 0.85 8.0 0.80 Lithium-ion battery 1.1 0.81 4.0 0.77 Nickel-based battery 5.0 0.81 5.0 0.81 Closed-loop pumped hydro 0.013 0.12 Open-loop pumped hydro 0.0075 0.081 Compressed air energy storage 0.010 0.10 Flywheel 18 0.20 061708-6 VanderMeer, Mueller-Stoffels, and Whitney J. Renewable Sustainable Energy 9, 061708 (2017) discharge (DOD), cycle life, year life, and efﬁciency shown in Table III. These values can vary widely depending on the system and how it is operated. Different energy storage technologies have different replacement costs, which affect LCOE and LCCP, but are not considered here. Figures 4 and 5 show a more detailed analysis on the cost of different ESS technologies and show the LCOE and LCCP for global and Alaska energy storage system installations. The mean values of LCOE and LCCP for global and Alaska data are shown in Table IV. Certain technologies have a lower LCOE, while others have a lower LCCP, indicating their feasibility for high energy or high power applications. Again, these values are best understood in the con- text of the projects they represent, described in Appendix B. Note that the values for ﬂow bat- teries have been calculated using cost data from non-operational projects and performance data from the literature that seem to be high based on the authors’ experience. Thus, these values may offer overly optimistic ﬁgures. Conditions for the greatest efficiency The efﬁciencies of ESS are largely inﬂuenced by the technology type (see the section on Expected Life and Efﬁciency) and usage. The three main forms of energy loss are charge/dis- charge (losses in energy storage medium and power electronics), storage (self-discharge), and parasitic due to balance of plant (e.g., cooling systems). An inefﬁciency is always associated with converting electrical energy into chemical or mechanical energy. Between technologies, levels of self-discharge vary, which results in losses during storage, with the more the losses, the longer the storage. Other factors such as temperature can play a signiﬁcant role as well. Thus, the conditions for the greatest efﬁciency are technology and use dependent. Cost curve over time The U.S. DOE, together with industry, has developed the near-term (present–2018) goals of under $250 per kWh of installed capacity for storage technologies and under $1750 per kW of rated power for power conditioning technologies. The long-term (2018–2023) goals are under $150/kWh for storage systems and under $1250/kW for power conditioning technologies (U.S. DOE, 2013). These numbers need to be converted into CAPEX for the entire energy storage TABLE V. Comparison of Sandia cost estimates with costs from global and Alaska data (2015 dollars) shows, on average, signiﬁcantly higher costs for Alaska. Sandia Global and Alaska Calculated from Sandia Global Alaska Tech1 Power conditioning cost ($/kW) Energy storage cost ($/kWh) Mean duration (h) Mean CAPEX/ power ($/kW) Mean CAPEX/ capacity ($/kWh) CAPEX/ power difference ($/kW) CAPEX/ capacity difference ($/kWh) CAPEX/ power difference ($/kW) CAPEX/ capacity difference ($/kWh) Flow battery 420 525 4.2 2625 625 5776 1819 1133 464 Lead-acid battery 420 346.5 1 766.5 766.5 1018.5 1018.5 2705.5 1713.5 Lead-acid battery (advanced) 420 346.5 0.25 506.625 2026.5 901.375 3607.5 821.375 3284.5 Lithium-ion battery 420 630 1.2 1176 980 1116 1135 996 6817 Nickel-based battery 292.5 780 0.31 534.3 1723.548 1133.7 4950.452 444.7 926.4516 Closed-loop pumped hydro storage 1260 78.75 10 2047.5 204.75 609.5 63.75 Open-loop pumped hydro storage 1260 78.75 13 2283.75 175.6731 1288.75 98.6731 Compressed air storage 735 5.25 18 829.5 46.08333 290.5 33.91667 Flywheel 630 1680 0.033 685.44 20770.91 2340.56 241207.1 061708-7 VanderMeer, Mueller-Stoffels, and Whitney J. Renewable Sustainable Energy 9, 061708 (2017) system and divided by capacity and power for comparison with the costs of the ESS presented in this paper. The total energy storage system costs (CAPEX) presented in this paper are an average of $591/kW, $6.6/kWh higher than the short-term goal (2018) and an average of $1213/kW and $860/kWh higher than the long-term goal (2023). Installed costs by major components Sandia’s reports include energy storage system costs by technology (Schoenung and Hassanzahl, 2003;Schoenung, 2011). The authors split the costs between the power condition- ing system, listed in $/kW, and the energy storage system, listed in $/kWh. The costs, updated to 2015 dollars, are shown in Table V. Sandia’s cost estimates have been converted to total CAPEX/capacity and CAPEX/power using the average duration of the different technologies. These costs have then been compared with the global and Alaska data. The difference between Sandia’s calculated costs and costs from the data is also shown in Table V. The data show, on average, signiﬁcantly higher costs except for pumped hydro storage, which is cheaper than Sandia’s costs. Transportation Only one data entry had an estimate for transportation costs: Kotzebue budgeted $40000 for the transport of a vanadium redox ﬂow battery from VRB (the project did not go through). Transportation costs are highly dependent on the weight, size, and shipping restrictions of the energy storage unit as well as the distance and available means of transportation to the end destination. Technology trends Recent material advances, especially in nanotechnology, have been signiﬁcant in the develop- ment of ESS: low-cost, long-life electrodes and membranes for ﬂow batteries, ﬂywheel design, increased surface area supercapacitors, and superconducting materials. New chemistries are the focus of research: different redox equations and electrolyte solutions for lower cost, higher perfor- mance, higher safety, and longer life of batteries and ﬂow batteries. Inverters and converters have been improving in performance and decreasing in price with advanced power electronics and new topologies. System design is a major part of bringing a technology out of the lab and into a prod- uct that is easy to use and maintain in the ﬁeld. The electric vehicle (EV) market is a major driver of ESS development, resulting in home and grid-connected batteries. Tech-specific storage systems Tech-speciﬁc storage systems (i.e., ultra-capacitors with wind) are not applicable to energy storage technology. Refurbishment/upgrade market For electro-mechanical ESS such as pumped hydro and ﬂywheels, refurbishment is often a cost-effective way to extend the life of the system. An example of a growing refurbishment market is old electric vehicle (EV) batteries. After the battery drops to 70%–80% of its initial capacity, it becomes insufﬁcient for automotive use. However, the battery is still useful for sta- tionary energy storage. Nissan is the ﬁrst EV manufacturer to launch a startup—Green Charge Networks—which resells old Nissan Leaf batteries as part of stationary storage systems (Neubauer and Pesaran, 2010;St. John, 2015). Realized cost savings Cost savings from integrating renewable power are difﬁcult to gauge due to technical and incentive impacts at the entire power system level. At the technical level, for example, effects of diminished losses of secondary services such as recovered waste heat and reductions in fuel efﬁciency are hard to gauge, as they depend not only on average reductions in load but also on 061708-8 VanderMeer, Mueller-Stoffels, and Whitney J. Renewable Sustainable Energy 9, 061708 (2017) speciﬁc operating schemes, such as minimum allowable loads on diesels and the spinning reserve kept. CONCLUSIONS Deployment of ESS is nascent in Alaska, with a few exceptions. Thus, the dataset devel- oped from AEA REF applications has been supplemented by data from the U.S. DOE Global Energy Storage Database, which captures installation data worldwide from Sandia National Laboratory’s energy storage reports (several editions) and data collected by ACEP through per- sonal communication with energy storage developers and utilities. Energy storage is hard to quantify in terms of performance, cost, and economic value. Costs and performance in the overall energy storage market have been evolving sporadically, and it is not easy to discern any clear trend. The most signiﬁcant trend in the data considered here is the increased variance in costs with time. Thus, more options for ESS with “low cost per kW/high costs per kWh” and vice versa are now available, indicating a greater variety of specialized ESS for targeted applications. It is often difﬁcult to justify energy storage economically based on fuel savings alone. Signiﬁcant work remains to quantify other possible cost savings afforded by energy storage, such as reduced fuel consumption and stress on a diesel generator by smoothing out the load. The data analyzed for this paper do not show any difference in the cost of energy storage in Alaska compared to the rest of the nation or world. Alaska has had relatively few energy storage technology failures, and most that occurred were caused by improper operation. Recent material advances, especially in nanotechnology, have been signiﬁcant in the devel- opment of ESS: low-cost, long-life electrodes and membranes for ﬂow batteries, ﬂywheel designs, and increased surface area supercapacitors and superconducting materials. New chem- istries are a focus of research with regard to different oxidation-reduction reactions and electro- lyte solutions for lower costs, higher performance, higher safety, and longer life of batteries and ﬂow batteries. Inverters and converters have been improving in performance and decreasing in price, with advanced power electronics and new topologies. The electric vehicle market is a major driver of energy storage system development, resulting in home and grid-connected bat- tery development. The lack of standardization and quantiﬁcation of costs and beneﬁts is the main barrier to determining the economic potential for implementation of energy storage in Alaska. In addition, communities in Alaska often wish to avoid ESS that uses hazardous materials since each com- munity will eventually have to deal with disposal issues. Energy efﬁciency grants could be leveraged for ESS. The development of standardized use scenarios for the operation of such systems would maximize the economic beneﬁts in Alaska. These scenarios would ideally include quantiﬁcation of economic savings, performance speciﬁ- cations for ESS manufacturers, and calculations of comparison metrics based on performance speciﬁcations. Guidance documents for determining needs, required speciﬁcations, and selection procedures for ESS would be extremely helpful. These documents should include information on how to protect an investment from technical failures by agreeing on performance and life- time guarantees as well as responsibility for failure. ACKNOWLEDGMENTS The authors wish tothank the Alaska Energy Authority for its funding tosupport this project. Many people have contributed information and insight to this study. We wish to thank Abbas Akhil and Ben Schenkman of Sandia National Laboratory, Tony Slatonbarker of Coffman Engineers, and Josh Craft and Neil McMahon of the Alaska Energy Authority for their review and comments. APPENDIX A: ADDITIONAL ANALYSIS AND PLOTS 061708-9 VanderMeer, Mueller-Stoffels, and Whitney J. Renewable Sustainable Energy 9, 061708 (2017) FIG. 6. Plot of CAPEX/capacity versus duration. The high cost per capacity of ﬂywheels and high duration of ﬂow batteries make this plot hard to read. FIG. 7. Plot of CAPEX/capacity versus duration with ﬂywheels and ﬂow batteries removed. FIG. 8. Plot of CAPEX/power versus duration. The high duration of ﬂow batteries makes this plot hard to read. FIG. 9. Plot of CAPEX/power versus duration with ﬂow batteries removed. 061708-10 VanderMeer, Mueller-Stoffels, and Whitney J. Renewable Sustainable Energy 9, 061708 (2017) TABLE VI. Lithium-ion battery.Project name Source Date State CountryPower(kW)Capacity(kWh)CAPEX/power($/kW)CAPEX/capacity($/kWh) NotesNICE GRID project inCarros (SouthernFrance): PrimarySubstation Battery(PSB)DOE 7/31/2013 Provence-Alpes-C^ote dAzurFrance 1000 450 817.62 1816.93 There are 3 “NICE GRID”data points, consistent CAPEX/capacitywith varying CAPEX/Power.Jake Energy StorageCenter: RES AmericasDOE 2/25/2015 Illinois United States 19800 7920 1022.66 2556.66 Relatively lowCAPEX/power andhigh CAPEX/capacity.Elwood Energy StorageCenter: RES AmericasDOE 2/25/2015 Illinois United States 19800 7920 1022.66 2556.66 Relatively lowCAPEX/power andhigh CAPEX/capacity.KIUC Anahola SolarArray and BatteryDOE 12/29/2014 Hawaii United States 6000 4980 1175.69 1416.49Anchorage AreaBattery Energy StorageSystemDOE and ARTEC 1/1/2016 Alaska United States 25000 14250 1208.00 2119.30 Data are from ARCTEC“2013 Railbelt Energy Priorities.”Stafford Hill SolarFarm and Microgrid:Lithium IonDOE 12/18/2014 Vermont United States 2000 2000 1259.67 1259.6710 MW/10 MWh—Feldheim RegionalRegulating PowerStation (RRKW)DOE 2/14/2015 Brandenburg Germany 10000 10800 1447.78 1340.545kWh LiFePO4DIY ESSDOE 11/3/2012 Ile de France France 2 4 1802.30 901.15APPENDIX B: REFERENCED ENERGY STORAGE PROJECTS AND SOURCESTablesVI–Xlist the energy storage projects studied in this paper and where they are sourced.REFrefers to the Renewable Energy Fund,DOErefers tothe DOE global energy storage database,EETFrefers to the emerging energy technology fund,ACEPrefers to the Alaska Center for Energy and Power, andARTECrefers to Alaska Railbelt Cooperative Transmission & Electrical Company. 061708-11 VanderMeer, Mueller-Stoffels, and Whitney J. Renewable Sustainable Energy 9, 061708 (2017) TABLE VI. (Continued.)Project name Source Date State CountryPower(kW)Capacity(kWh)CAPEX/power($/kW)CAPEX/capacity($/kWh) Notes2 MW/4.4 MWh PugetSound Energy—Glacier WADOE 12/17/2014 Washing-ton United States 2000 4400 1914.69 870.31Oncor Battery Storage DOE 6/23/2014 Texas United States 250 750 2006.43 668.81JuiceBox Residentialsolar energy storageSES—AC-coupledpeak-shifting andbackupDOE 5/10/2015 California United States 5 5.85 2009.11 1717.19Landing Mall DR DOE 5/21/2011 Washing-ton United States 75 39.75 2117.78 3995.80 Remotely controlled byutility for demand response.Tuntutuliak REF 1/1/2011 Alaska United States 250 62.5 2654.00 10617 Tuntutuliak and Kwigillingok areidentical REF applications.Both were declinedfunding due to control andintegration issues.Kwigillingok installed Chevy-voltbatteries withan ABB PCS-100 inverter,the same specs and price.The very highCAPEX/capacity is likely partly dueto the very low duration.Kwigillingok REF 1/1/2011 Alaska United States 250 62.5 2654.00 1061790 kW/180 kWh SantaCruz County BuildingGCNDOE 9/28/2015 California United States 90 180 2784.15 1392.08ZECO Energy DOE #N/A Victoria Australia 33 41.25 3030.30 2424.24 This installation is off-grid,which is likely the cause for therelatively high cost.NICE GRID project inCarros (SouthernFrance): SecondaryDOE 8/24/2013 Provence-Alpes-C^ote dAzur France 250 480 3672.46 1912.74 There are 3 “NICE GRID”data points, consistentCAPEX/capacity with 061708-12 VanderMeer, Mueller-Stoffels, and Whitney J. Renewable Sustainable Energy 9, 061708 (2017) TABLE VI. (Continued.)Project name Source Date State CountryPower(kW)Capacity(kWh)CAPEX/power($/kW)CAPEX/capacity($/kWh) NotesSubstation Battery(SSB)varying CAPEX/Power.Fort Hunter LiggettBattery Storage ProjectDOE 10/1/2013 California United States 1000 1000 4074.23 4074.23 This installation is on a military base.Perhaps higher building standardsresult in high cost.NICE GRID project inCarros (SouthernFrance): Low VoltageGrid Batteries (LVGB)DOE 8/23/2013 Provence-Alpes-C^ote dAzur France 33 84.81 4636.94 1804.26 There are 3 “NICE GRID”data points, consistent CAPEX/capacity withvarying CAPEX/Power.UBC ElectrochemicalEnergy Storage ProjectDOE 11/6/2012 British Columbia Canada 1000 1000 5252.40 5252.40 This was installed on auniversity campus andintended for researchas well as grid support, whichpossibly led to high costs. 061708-13 VanderMeer, Mueller-Stoffels, and Whitney J. Renewable Sustainable Energy 9, 061708 (2017) TABLE VII. Lead-acid battery.Project name Source Date State Country Power (kW)Capacity(kWh)CAPEX/power($/kW)CAPEX/capacity($/kWh) NotesPREPA BESS 2 DOE 4/21/2002 Puerto Rico United States 20000 13400 763.6019 1139.704 This is the cost of replacing the existing installa-tion “PREPA BESS 1.” Having existing infra-structure results in the lowest CAPEX/Power.Stafford Hill Solar Farm andMicrogrid: Lead AcidDOE 12/18/2014 Vermont United States 2000 2400 1259.665 1049.721Kodiak-Pillar Mountain REF 1/1/2012 Alaska United States 3000 750 1327.818 5311.273 This is an “advanced” lead acid battery, whichresults in a higher CAPEX/capacity.KIUC Koloa—Xtreme Power DPR DOE 7/15/2011 Hawaii United States 1500 375 1408.405 5633.622 This is an “advanced” lead acid battery, whichresults in a higher CAPEX/capacity.PREPA BESS 1 DOE 2/10/1992 Puerto Rico United States 21000 14070 1660.707 2478.667 The higher cost is likely due to the early instal-lation date.Metlakatla BESS DOE 2/3/1997 Alaska United States 1000 1400 3459.063 2470.759 The higher cost is likely due to the early instal-lation date as well as being installed in a remotemicrogrid.061708-14 VanderMeer, Mueller-Stoffels, and Whitney J. Renewable Sustainable Energy 9, 061708 (2017) TABLE VIII. Flow battery.Project name Source Date State Country Power (kW)Capacity(kWh) CAPEX/($/kW)CAPEX/Capacity($/kWh) NotesKotzebue PremiumPowerREF 1/1/2010 Alaska Unite States of America 500 3700 1655.345 223.6953 The cost of purchasing, transporting, andinstalling a Zinc-Bromine Flow Batteryfrom Premium Power. It did not perform torequired specs, was decommissioned.RedFlow 300 kWAdelaideDOE 4/17/2015 South Australia Australia 300 660 3363.406 1528.821 The cost of purchasing and transporting aZinc-Bromine Flow Battery from RedFlow.Under construction.Kotzebue VRB REF 1/1/2008 Alaska Unite States of America 600 1800 5860.927 1953.642 The price quoted to Kotzebue for aVanadium Redox Flow Battery before VRBwent out of business.Minami HayakitaSubstation VanadiumRedox Flow BatteryDOE 4/17/2014 Hokkaido Japan 15000 60000 13438.93 3359.733 Project cost of installing Vanadium RedoxFlow Batteries. These costs are much higherpossibly due to higher infrastructure costs.Contracted/under construction. 061708-15 VanderMeer, Mueller-Stoffels, and Whitney J. Renewable Sustainable Energy 9, 061708 (2017) TABLE IX. Flywheel.Project name Source Date State Country Power (kW)Capacity(kWh)CAPEX/power($/kW)CAPEX/capacity($/kWh) NotesChugach FESS EETF 5/26/2015 Alaska United States of America 200 25 2210 17680 The installed cost of Flywheel energy storagefor Chugach’s announced project.Kwigillingok FESS REF 1/1/2010 Alaska United States of America 500 5 3100 310010 Kwigillingok, Tuntutuliak, and Kongiganaksubmitted identical REF applications which were not funded.Kipnuk also was not granted funding throughREF. Kwigillingok installed Lithium-ion Batteries instead.The high CAPEX/Capacity is due to the low Capacity.Tuntutuliak FESS REF 1/1/2010 Alaska United States of America 500 5 3100 310010Kongiganak FESS REF 1/1/2010 Alaska United States of America 500 5 3100 310010Kipnuk high penetration REF 1/1/2010 Alaska United States of America 500 5 3622 362183 061708-16 VanderMeer, Mueller-Stoffels, and Whitney J. Renewable Sustainable Energy 9, 061708 (2017) APPENDIX C: EQUATIONS FOR LCOE AND LCCP Equations for LCOE: LCOE ¼NPVc CRF AnnualEnergyStored ; NPVc ¼CAPEX þ XN j¼1 1 þ i 1 þ r j OM; CRF ¼r 1 ð 1 þ rÞ N ; AnnualEnergyStored ¼Cap DOD g Cycles Years ; where NPVc is the net present value of the annual cost of the system,CRF is the capitol recovery factor (the ratio of a constant annual cost to the present value of that cost),CAPEX is the capital TABLE X. Pumped storage and compressed air energy storage. Project name Source Date State Country Power (MW) Capacity (MWh) CAPEX/ power ($/kW) CAPEX/ capacity ($/kWh) Notes Yards Creek Pumped Storage DOE #N/A New Jersey United States 400 2400 38 6 Open-loop pumped hydro Blenheim-Gilboa Pumped Storage Power Project DOE 7/1/1973 New York United States 1160 17400 659 44 Open-loop pumped hydro Northﬁeld Mountain Pumped Storage Hydroelectricity Facility DOE 12/31/1969 Massachusetts United States 1119 8482 790 104 Open-loop pumped hydro Raccoon Mountain Pumped Storage Plant DOE 1/1/1974 Tennessee United States 1652 36344 934 42 Open-loop pumped hydro Silver Creek Pumped Storage Project DOE 5/15/2012 Pennsylvania United States 300 2400 1041 130 Closed-loop pumped hydro McIntosh Compressed Air Energy Storage Plant DOE 1/1/1991 Alabama United States 110 2860 1048 40 Compressed air energy storage Paciﬁc Gas and Electric Company Advanced Underground Compressed Air Energy Storage DOE 1/1/2015 California United States 300 3000 1192 119 Compressed air energy storage Bath County Pumped Storage Station DOE 1/12/1985 Virginia United States 3003 30930.9 1200 117 Open-loop pumped hydro Lake Elsinore Advanced Pumped Storage DOE 8/6/2007 California United States 500 6000 1835 153 Closed-loop pumped hydro Ingula Pumped Storage Scheme DOE 11/1/2007 Kwa-Zulu Natal South Africa 1332 21312 2350 147 Open-loop pumped hydro open-loop pumped hydro 061708-17 VanderMeer, Mueller-Stoffels, and Whitney J. Renewable Sustainable Energy 9, 061708 (2017) expenditure,i is the inﬂation rate,r is the interest rate,N is the system lifetime in years,Cap is the capacity of the installation,DOD is the depth of discharge,g is the efﬁciency,Cycles is the number of cycles the system is rated for, and Years is the number of years the system is rated for. Equations for LCCP: LCCP ¼NPVc CRF Cycles Power=Years ; where Power is the rated power of the energy storage system. Butler, P., Grimes, P., Klassen, S., and Miles, R.http://www.sandia.gov/ess/publications/SAND2000-0893.pdf for “Zinc/ Bromine Batteries,” Sandia Report No. SAND2000-0893, 2000. Divya, K. and Ostergaard, J., “Battery energy storage technology for power systems—An overview,”Electr. Power Syst. Res.79(4), 511–520 (2009). Neubauer, J. and Pesaran, A.,http://www.nrel.gov/transportation/energystorage/pdfs/48018.pdf for “PHEV/EV Li-Ion Battery Second-Use Project,” NREL presentation, 2010. Schaede, H., Schneider, M., VanderMeer, J., Mueller-Stoffels, M., and Rinderknecht, S., “Development of kinetic energy storage systems for Island Grids,” in International Renewable Energy Symposium 2015, March (2015). Schoenung, S., “Energy storage systems cost update,” Sandia Report No. SAND2011-2730 (2011). Schoenung, S. and Hassanzahl W., “Long- vs. short-term energy storage technologies analysis,” Sandia Report No. SAND2003-2783 (2003). St. John, J.,http://www.greentechmedia.com/articles/read/nissan-green-charge-networks-turn-second-life-ev-batteries-into- grid-storag for “Nissan, green charge networks turn ‘Second-Life’ EV batteries into grid storage business,” Greentech Media article (2015). U.S. Bureau of Labor Statistics,https://research.stlouisfed.org/fred2/data/CPIAUCSL.txt for “Consumer price index for all urban consumers: All Items,” CPIAUCSL; accessed January 2016. U.S. Department of Energy,http://energy.gov/sites/prod/ﬁles/2014/09/f18/Grid%20Energy%20Storage%20December%20 2013.pdf for “Grid Energy Storage,” U.S. Department of Energy Report, December 2013. U.S. Department of Energy,www.energystorageexchange.org/projects for “Global Energy Storage Database” (retrieved in 2017). Viswanathan, V., Kintner-Meyer, M., Balducci, P., and Jin, C.,http://energyenvironment.pnnl.gov/pdf/National_ Assessment_Storage_PHASE_II_vol_2_ﬁnal.pdf for “National Assessment of Energy Storage for Grid Balancing and Arbitrage Phase II Volume 2: Cost and Performance Characterization,” Paciﬁc Northwest National Laboratory, PNNL-21388, 2013. 061708-18 VanderMeer, Mueller-Stoffels, and Whitney J. Renewable Sustainable Energy 9, 061708 (2017)