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An Investigation Into Energy Storage Technologies For the University of British Columbia’s New Student… Baum, Travis; Grewal, Guggy; Heffernan, Dale 2010-11

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UBC Social Ecological Economic Development Studies (SEEDS) Student Report             An Investigation Into Energy Storage Technologies For the University of British Columbia’s New Student Union Building Travis Baum, Guggy Grewal, Dale Heffernan University of British Columbia APSC261 November 22, 2010         Disclaimer: “UBC SEEDS provides students with the opportunity to share the findings of their studies, as well as their opinions, conclusions and recommendations with the UBC community. The reader should bear in mind that this is a student project/report and is not an official document of UBC. Furthermore readers should bear in mind that these reports may not reflect the current status of activities at UBC. We urge you to contact the research persons mentioned in a report or the SEEDS Coordinator about the current status of the subject matter of a project/report”.  AN INVESTIGATION INTO ENERGY STORAGE TECHNOLOGIES FOR THE UNIVERSITY OF BRITISH COLUMBIA’S NEW STUDENT UNION BUILDING  By  Travis Baum Guggy Grewal Dale Heffernan    Report Prepared For: Dr. Paul Winkleman, Course Instructor  University of British Columbia Applied Science 261 November 22, 2010   ii ABSTRACT  “An Investigation into Energy Storage Technologies for the University of British Columbia’s New Student Union Building”  By                            Travis Baum                          Guggy Grewal                          Dale Heffernan   This report investigates the potential of flywheel energy storage (FES) and vanadium reduction-oxidation flow batteries (VRB) as methods of storing renewable energy generated at the new student union building (SUB). One of the long term design goals of the new SUB is that the building will be able to generate enough energy through the use of photovoltaic cells to supply its annual energy demand.  In order to assess the feasibility of the implementation of FES and VRB technologies in the new SUB, the assessment for each technology has been broken down into three parts: economic, social and environmental impacts.  After assessing the two energy storage technologies, this report recommends that energy conservation coupled with a relatively small amount of VRB installed storage is the most effective means of having the new SUB meet its goal of energy self sufficiency. In order for the SUB to meet its goal of “Net Zero Consumption” the planned renewable energy capacity would need to be drastically increased. VRB technology is a suitable candidate for storing energy because of its ease of scalability, relatively constant round trip efficiency, long life and small footprint. In addition, the technology has a relatively small impact on the environment and would help justify the increased renewable energy capacity by storing surplus energy to be used at later times to allow the renewable system meet peak energy demand.   iii TABLE OF CONTENTS ABSTRACT ................................................................................................... ii LIST OF ILLUSTRATIONS ........................................................................ iv GLOSSARY ................................................................................................... v LIST OF ABBREVIATIONS ....................................................................... vi 1.0  INTRODUCTION ............................................................................... 1 2.0 The NEW STUDENT UNION BUILDING ........................................ 2  2.1 Generation Supply Projections .................................................... 2  2.2 Load Demand Projections ........................................................... 4 3.0 FLYWHEEL ENERGY STORAGE ..................................................... 8  3.1 BACKGROUND AND HISTORY OF TECHNOLOGY ........... 8  3.2 ECONOMICAL FEASIBILITY ANALYSIS ........................... 10  3.3 SOCIAL IMPLICATIONS ........................................................ 10  3.4 ENVIRONMENTAL IMPACT ..................................................11 4.0 VANADIUM REDOX FLOW BATTERY STORAGE ..................... 12  4.1 BACKGROUND AND HISTORY OF TECHNOLOGY ......... 12  4.2 ECONOMICAL FEASIBILITY ANALYSIS ........................... 14  4.3 SOCIAL IMPLICATIONS ........................................................ 14  4.4 ENVIRONMENTAL IMPACT ................................................. 15 5.0 COMPARISON OF ENERGY STORAGE TECHNOLOGIES ........ 17 6.0 CONCLUSION AND RECOMMENDATIONS ................................ 19 REFERENCES ............................................................................................ 20 APPENDIX: FIGURE SOURCES .............................................................. 21   iv LIST OF ILLUSTRATIONS  Figure 1:  Average Daily Sunlight Duration And Bright Sunshine................... 3 Figure 2: Average Daily Energy and Power ........................................................ 4 Figure 3: Degree-Days For Vancouver Over The Course Of 30 Years ............ 5 Figure 4: Breakdown of Average Daily Energy Consumption .......................... 6 Figure 5: Average Daily Energy Production to Consumption Ratio ................ 7 Figure 6: Schematic Drawing Of A Typical Modern Day Flywheel ................ 8 Figure 7: Beacon Power Flywheel Unit  and Cutaway View Rendering ......... 9 Figure 8: Cost of Flywheel Energy Storage ......................................................... 10 Figure 9: Basic VRB System Schematic .............................................................. 12 Figure 10: VRB Half Cell And Overall Chemical Reactions ............................ 13 Figure 11: Cost of Vanadium Redox Battery Storage ......................................... 14    Table 1: Breakdown of Annual Energy Consumption and Generation ............ 2 Table 2: Monthly Weather Statistics ..................................................................... 5 Table 3: Material Prosperities for Flywheels ...................................................... 11 Table 4: Life-Cycle Energy Use and CO2 Production ........................................ 16 Table 5: Comparison of FES and VRB Technologies ........................................ 17  v GLOSSARY  Angular velocity:  The speed at which an object rotates around an axis. Building integrated photovoltaic:  Photovoltaic materials used to replace conventional building materials (ie. Skylights and roof) Catastrophic Failure:  Total failure in which the system is unable to recover. In the case of FES, this leads to the destruction of the unit and damage to the surrounding area. Degree-Days:  A measurement of heating or cooling. Kilo-Watt:  Unit of Power, 1kW = 1000W Kilo-Watt hour:  Unit of energy, 1kWh = 3.6M joules Load:  Anything that takes electricity to work. Load smoothing:  To shift the consumption of energy so that it is more uniform. Moment of Inertia:  The tendency of a body to resist angular acceleration. Net-Zero Energy Consumption:  Electricity consumption when over the duration of a year the total amount of energy consumed from the grid has at least been generated, effectively nullifying the grid power consumption. Peak shaving:   Using stored energy to supply any excess energy demand that exceeds base load. Production to consumption ratio:  The percentage of the building’s energy demand met by its renewable energy generation. Proton exchange membrane:  A semi-permeable membrane that conducts protons while being impermeable to gases such as hydrogen and oxygen. Ramp up:  The process of moving from basically no generation to rated generation. Reduction- Oxidation:  Chemical reactions in which the number of electrons (oxidation number) is either increased or decreased (as opposed to forming new molecule). Round Trip Efficiency:  The overall efficiency of a system from the time raw AC is converted to chemical/mechanical energy to the time the chemical/mechanical energy is converted back to AC power. Total bright hours of sunshine:  Sunshine that is intense enough to generate to use for power generation. This threshold is 100W/m2 Vanadium:  A Common metal widely distributed in nature. Photovoltaic Cell:  A silicon based device that generates a current when light is shone on it.  vi LIST OF ABBREVIATIONS  SUB Student Union Building LEED Leadership in Energy and Environmental Design THBS Total Hours of Bright Sunshine FES Flywheel Energy Storage BIVP Building integrated photovoltaic VRB Vanadium Reduction-Oxidation Battery PEM Proton Exchange Membrane VO5 Vanadium Pent-oxide PVC Polyvinyl Chloride SO4 Sulfuric Acid DHW Domestic Hot Water     1 1.0 INTRODUCTION The construction of a new, environmentally sustainable Student Union Building (SUB) was approved by the students of UBC in a referendum vote last year. Current designs of the new SUB building incorporate the use of photovoltaic cells* as a renewable energy source. Unfortunately, this kind of energy source is intermittent in nature. In order to improve reliability of the photovoltaic system and to help the SUB achieve net-zero energy consumption*, an energy storage system may be used to store excess energy when there is an energy surplus and then supply stored energy to the SUB when there is an energy deficit. This will reduce the amount of energy that the SUB requires from the distributed power grid since generated energy can be used over a longer period of time (as opposed to instantaneously) which will also help justify the cost of the expensive photovoltaic cells.  This report looks at two technologies as potential storage technologies to be used in the new SUB: flywheel energy storage (FES) and vanadium reduction-oxidation* flow batteries (VRB). Each technology will be assessed according to their economical, environmental and social impacts. Published papers and commercial websites focused on the two technologies will be examined as well as a document supplied by the new SUB’s design team (HBBH+BH and associates) regarding the renewable energy and building load* profile. The main section of the report include: The New Student Union Building, Flywheel Energy Storage and Vanadium Redox Flow Battery Storage.     *this term  as well as all subsequent terms can be found in the glossary p. V   2 2.0 THE NEW STUDENT UNION BUILDING UBC’s long-term goal for the new SUB building is to produce enough renewable energy to achieve net-zero energy consumption. In the short term, UBC is aiming build the new SUB so that it will be the most sustainable student union building in the world and to achieve LEED Platinum status  In order to achieve LEED certification, a minimum of 25% of the energy consumed by the SUB must be sourced from renewable energy generated within the foot-print of the building. Current, designs plan to implement solar panel arrays to produce this renewable energy [1]. In order to improve the reliability of the solar array as an energy source, an energy storage system may be installed.  An energy storage system would store surplus energy during times of low energy demand and high energy generation for use during subsequent periods of low energy generation and high energy demand. Sections 2.1 and 2.2 estimate the frequency and duration of the surplus energy periods in order to determine whether installing an energy storage is a feasible as well as to roughly estimate how much storage may be required for the SUB.  2.1 Generation Supply Projections Table 1 is a summary of the annual energy consumption/generation of the various components of the new SUB building based on energy consumption and production projections supplied by HBBH+BH Associated Architects [1].  Table 1: Breakdown of Annual Energy Consumption and Generation Load Component (MWh) Generator Component (MWh) Lighting 290 Solar Cell Array 320 Plug Load 486 Space Heating 253 Space Cooling 253 Pumps 260 Fans 155 DHW 400 Total : 1864  320    3 At the annual level, it is clear that the energy produced from solar panels (320MWh) is much less than the energy consumed (1864MWh) However, if this data is separated into periods of days or hours, instances when supply is greater than demand do exist.  Since things like weather, day light hours and student traffic vary throughout the year, energy consumption and power generation vary during different times of year and a surplus of power may occur.  It was assumed that solar power generation is proportional to the amount of bright sunshine in a year. Given that the solar panels are estimated to generate 320 MWh annually and that they generate power during times of bright sunshine, it is reasonable to distribute the annual generation over the months of the year based on the total hours bright sunshine* (THBS) in a given month. Figure 1 displays the average monthly sunlight and THBS based on historical data of the Vancouver area.  Figure 1: Average Daily Sunlight Duration and Bright Sunshine    4 The weighted daily energy generated was calculating by multiplying the annual energy generation by the proportion of the hours of daily sunlight divided by the annual amount of sunlight.  Figure 2 displays the estimated monthly power generation. This was calculated by adding the daily weighted average of power generation over each month. It can be observed that the power generated from month to month can vary by a large amount. Energy production can be as low as 306 kWh in December to as high as 1610 kWh in July.   Figure 2: Average Daily Energy and Power  2.2  Load Demand Projections Similar to the generation supply projections, approximations were made to determine the monthly distribution of energy consumption.  Table 2 contains the monthly heating degree-days, cooling degree-days and total hours of bright sunshine. Based on historical weather data, monthly energy consumption was estimated for lighting, space heating and cooling [2].   5 Table 2: Monthly Weather Statistics [] Month Total hours bright sunshine Above 18 °C (cooling Degree days) Below 18 °C (heating Degree days) Sept 199 3 85 Oct 125 0 215 Nov 64 0 330 Dec 56 0 408 Jan 60 0 413 Feb 85 0 344 Mar 134 0 326 Apr 182 0 242 May 231 1 151 Jun 229 8 70 Jul 295 28 26 Aug 268 32 21  THBS (refer to table 1) was used to calculate the amount of lighting energy would be required per month. It is assumed that there is an inverse relationship between THBS and total lighting energy required. In other words, less sunshine results in more energy being used for lighting the building.   Figure 3: Degree-Days For Vancouver Over The Course Of 30 Years   6 Degree-days* were useful in determining the monthly distribution of energy consumed in heating and cooling the building. The remaining portion of energy consumed (pumps, plug load, fan and DHW) was estimated based on a weighted average of expected daily traffic. It is estimated that 8,500 people use the SUB in some manner on a daily basis during the two terms of the winter session. During the summer session, human traffic is expected to be reduced by about one-third of the winter session. Approximations resulted in the projection are combined and summarized in figure 4.   Figure 4: Breakdown of Average Daily Energy Consumption  According to this figure 4, the average daily consumption is highest in December (6690 kWh) and the lowest in May (2244 kWh.)  It is worth noting that energy consumption in the summer months is not as low as one may expect. This is due to the incredible amounts of energy required to cool the building.   7  Figure 5: Average Daily Energy Production to Consumption Ratio*  Figure 5 compares the average daily energy production with the average daily energy consumption. When comparing the average daily production and consumption of energy, it can be observed that even on a daily level, there is never an energy surplus.  On average, the highest production to consumption ratio occurs in May (56.2%) and the lowest occurs in December (4.6 %.)  It is also worth mentioning that for one-third of the year (November, December, January and February), the production to consumption ratio is less than 8%.  In order to start generating a surplus on the daily scope (long-term storage), the annual energy generated by solar panels would have to be increased to a minimum of 570MWh (a 78% increase over the current projection).  Despite this drastic increase in energy production, for one-quarter of the year the production to consumption ratio would still be a single digit percentage. Based on an average hourly power load of ~200kW (refer to Appendix for average daily load) an energy storage system of 150kW, 150kWh rating will be used in the following two sections of the report. This size system would have the capacity to power 75% of the load for an hour which is thought to be reasonable for the relatively small amount of surplus generation expected to be available for storage.   8 3.0  FLYWHEEL ENERGY STORAGE Flywheels are mechanical devices that store rotational energy by rotating a mass at high velocity (refer to figure 6). Kinetic energy is generated via the inertia and speed of the rotating mass (which is driven by the motor) and is stored as rotational energy. Energy is removed from the system by using the rotation of the flywheel to either spin a motor or power a generator, or simply by the reserve process of charging the flywheel system.   Figure 6: Schematic Drawing of a Typical Modern Day Flywheel [3].  3.1 BACKGROUND AND HISTORY OF TECHNOLOGY Flywheels have existed and been used for the past two centuries. Their initial purpose was to smooth out mechanic systems by adding mass, thus momentum to the system. Flywheels were not considered as a means to store energy until the 1960’s and 1970’s when NASA began research into the their use for space missions [3,4].  In modern systems, the flywheel is housed inside a vacuum to reduce energy loss due to drag and is suspended by either steel or magnetic bearings to reduce contact friction. In addition, the vacuum chambers and magnetic bearing also reduce wear on parts (since there is less friction stress on the components) leading to reduced maintenance on the   9 systems. [3] The two governing principles in how much energy a flywheel can store are the moment of inertia* and angular velocity* of the flywheel. The simplest way to increase the power of a flywheel is increase its speed; however the inertial loads generated can overcome the tensile strength of the material used to construct the flywheel, leading to catastrophic failure* [3]. In order to prevent overstressing flywheel units,, researcher have experimented with both the shape of the flywheel and the material used in order to achieve high velocities safely. In new systems, composite material which perform well under high tensile loads are used.   Figure 7: Beacon Power Flywheel Unit and Cutaway View Rendering  Flywheel Energy Storage (FES) systems have been used in number of different applications from smoothing power output of intermittent energy generation sources (such as wind turbines) to extending load supply times for renewable energy generation. In 2001, a FES system was used in conjunction with a building integrated photovoltaic* (BIVP) in Hong Kong to increase the load supply time from 9 am – 3 pm to 8am – 6pm [3]. Beacon Power, Massachusetts USA, currently has two flywheel units used for voltage stability installed in the United States – one in Amsterdam, NY and the other in   10 San Ramon, CA. Figure 7 is a photo of one of Beacon Power’s flywheels next a 3D cut away view of a FES system [5]. In both systems, flywheels are used to either absorb or release energy according to the current frequency of the system. These systems consist of seven flywheels with 30kWh of collective energy storage. This is enough energy to supply a 5kW load for six hours. [5]  3.2 ECONOMICAL FEASIBILITY ANALYSIS Currently, FES systems are still quite high at about $700 to $800 per kWh and approximately $200 to $500 per kW [6,7]. In the foreseeable future, however, the cost of FES systems will decrease as the price of expensive materials needed for high efficiency, high energy density units decreases. One of the key selling features of FES systems is the high round trip efficiency of the units. A typical FES system, of about five kWh, has a round trip efficiency* of greater than 90% [8]. This is a much higher efficiency than most other systems such as hydrogen fuel cells which have a round trip efficiency as low as 40% [9]. Figure 8 shows a rough calculation for the cost of a FES system for the new SUB. It is estimate that a 150kW, 150kWh VRB unit will have an initial capital cost of approximately $165,000 with negligible maintenance and disposal costs.  Capital Cost = $750 x (kW rating) + $350 x (kWh rating) Figure 8: Cost of Flywheel Energy Storage [6]  3.3 SOCIAL IMPLICATIONS FES systems have very little social implications. FES systems require a small amount physical space due to the high energy densities that can be achieved. Figure 9 summaries the energy densities (Esp) that can be achieved in FES system depending on the material used for the flywheel.    11  Table 3: Material Prosperities for Flywheels [4]  The main social implication of a FES system is safety. Due to the nature of rotating a mass at high velocity the tensile strength the flywheel material can be overcome leading to failure. Such a failure could be catastrophic* so researchers and developers have optimized the shape of flywheels and materials used to construct them. σm in figure 9 represents the tensile strength of material used in flywheels, this is much higher than that of A36 Steel (structural steel) which has a σm of 0.4GPa [10] meaning that they can handle much higher rotational velocities and stress than regular building materials. In addition to using specialized flywheel materials, vacuum chambers are lined with thick steel and are usually located underground away from people in order to increase the safety of flywheel systems Storing these system underground has the added benefit of reducing the usable space taken up by the storage/leveling system.  3.4 ENVIRONMENTAL IMPACT FES systems do not directly produce any emissions while in use. However, during the production of steel for the vacuum chamber and the production of materials need for constructing the flywheel and the generator/motor, CO2 and other emissions are produced. The materials used in flywheel construction (such as copper, steel, and composite fibers) can all be sourced in North American, reducing the need for international shipment and thereby lowering the carbon footprint of the system.   12 4.0  VANADIUM REDOX FLOW BATTERY STORAGE Vanadium reduction-oxidation* flow battery storage (VRB) is a chemical energy storage system that stores power in the form of two electrolytic* solutions of vanadium oxide and vanadium ions. Flow batteries differ from traditional batteries in that they require at least two pumps to transport the charged electrolytic solutions across a proton exchange membrane* (PEM) in order to generate electricity. Figure 10 outlines the basic components of a VRB system.  Figure 9: Basic VRB System Schematic [11]  4.1  BACKGROUND AND HISTORY OF TECHNOLOGY Figure 11 expresses the two half cell equations as well as the overall chemical reaction for the cell. Since the battery only requires the use of one basic electrolyte (in different oxidation states), irreversible cross contamination (like in other flow battery technologies such as Zinc-Bromine) is impossible.    13  Negative Half Cell:   23 VeV  Positive Half Cell:    eHVOOHVO 2222  Overall Cell:   HVOVOHVOV 222223 Figure 10: VRB Half Cell and Overall Chemical Reactions [11]  VRB technology was first developed in the 1980s and was patent protected until the early 2000s. Since the patent expired, more and more companies have been entering the VRB market, marketing the batteries to be used for uninterrupted power supply, peak shaving* and load smoothing* devices for telecom, off-grid applications and renewable power generation. There have been numerous instances of VRBs being used to level the generation of intermittent renewable energy sources such as wind and solar. Examples include: 0.2MW, 0.9MWh unit in King Island Australia, 4MW, 6MWh unit in Sapporo Japan and 0.25MW, 2MWh unit in Castle Valley, Utah. [12]  Since batteries are an array of cells configured in parallel and series, VRB batteries can be scaled quite easily to supply rated power from kilowatts to megawatts. Capacity of the battery is directly proportional to the amount of charged electrolytic solution available so by adding additional storage tanks, the energy capacity of these systems can range from kilowatts to megawatts. The current energy density of VRBs are in the range of 20- 30Wh/L[13]. A 150kWh unit would require about 6000L of solution which would have a foot print of two square metres (if three metres in height) – easily fitting in any space in the SUB. The current AC round trip efficiency of VRB batteries is around 45% which is very competitive with other storage technologies. In addition, because there is virtually no discharge during storage, this technology is suited well for long term power storage.    14 4.2  ECONOMICAL FEASIBILTY ANALYSIS The majority of the life-cycle costs of a VRB system are contained within the upfront cost to purchase and install the system. Figure 12 calculates a very rough estimate on the cost of a unit based on rated power and energy capacity. It is estimate that a 150kW, 150kWh VRB unit will have an initial capital cost of approximately $182,000.  Capital Cost = $1,100 x (kW rating) + $110 x (kWh rating) Figure 11: Cost of Vanadium Redox Battery Storage (adapted from Tables 3 & 4 [14])  Regular maintenance on the VRB is minimal – consisting of visual inspections of VRB piping, HVAC and pumps every six months and bolt torque checked every year [13]. The pump bearings and O-rings may need replacement in five year intervals. The cell stacks are the limiting component of the life of the VRB system – estimated to last approximately 10-15 years. The stacks can be refurbished by replacing the PEM which wears with time. Replacement of the PEM in the stacks is estimated to be about 11% of the initial capital cost (~$20,000) [13].  If pumps and cell stacks are maintained and refurbished as necessary, a VRB has an expected life of easily more than 20 years. Disposal and recycling costs associated with the unit are also minimal since the electrolytic solution can be virtually reused indefinitely. For the Tanks, piping and cell stacks, standard commercial processes to dispose and recycle are available.  4.3  SOCIAL IMPLICATIONS The majority of the material and chemicals used in the manufacturing of these batteries will be produced or sourced in North America where human rights and health are seldom violated. Vanadium pent-oxide (VO5) (which is used to make the electrolyte solution) may originate from a region where ethnical practices may be suspect, however it would be very difficult to trace its origins since VO5 is a widely traded commodity in North   15 America (where it is primarily used in strengthening steel).  Since VRBs do not contain any heavy metals [11] and are designed to be fully closed systems, the batteries will not have any health implications on the student population of UBC. However, due to the nature of the product (dealing with large amounts of power and energy) a VRB system would best be isolated from the student population so the effectiveness of using a VRB storage system to demonstrate energy storage technology is quite small. However, a VRB system (similar to any reliable energy storage system) would have an indirect positive impact on the local student population by allowing intermittent, renewable energy sources such as wind and solar be a viable option for power generation. Most renewable generation (wind, solar, tidal, run of river hydro) ramp up* and down quite quickly and generally do not match power load demand. A battery would be able to store surplus energy and then release it on demand – making the system a slightly more reliable and reducing the need to switch back and forth between renewable and grid power during times of intermittent generation.  4.4  ENVIRONMENTAL IMPACT VRBs are much more environmentally friendly than other battery energy storage technologies [11]. VRB systems have a fairly low toxicity since they do not require heavy metals in their construction such as nickel, cadmium, lead or zinc. Heavy metals are generally toxic and will harm the surrounding environment if concentrations become large enough. However, similar to lead acid batteries, VRBs require sulfuric acid (SO4) to form the vanadium solutions. Concentration of SO4 in VRB batteries is approximately the same as that of lead-acid battery [13]. However, unlike lead-acid batteries, once the aqueous solution of vanadium ions is created it can virtually be used indefinitely [14] so there is minimal environmental impact on the environment once the solutions are produced. Sulfuric acid is one of the largest manufactured chemicals in the US and in the   16 world and is readily available for construction of VRB units. The storage tanks and piping are usually made with fiberglass or polyvinyl chloride (PVC) as they are very common materials and can withstand the acidic environment.  The most energy intensive components of the VRB system are the initial process of extraction to vanadium solutions and the production of the cell stacks. Vanadium is commonly found around the world in a variety of ores (bauxite, vandinite, camotite) and carbon containing deposits (shale, coal, crude oil) [13], however needs to be refined before being used. The power stack is the most complicated component of the VRB system containing parts that require specialized and energy intensive production techniques (such as the proton exchange membrane). Table 3 summarizes an estimate of the embodied energy and carbon dioxide used and produced for a 150kWh unit.  Table 4: Life-Cycle Energy Use and CO2 Production [15] Component GJ/MWh Tons CO2/MWh GJ/150kWh Tons CO2/150kWh Electrolyte materials and manufacturing 453 32.0 67.95 4.8 Power Stack materials and manufacturing 986 70.7 147.9 10.605 PCS 236 16.8 35.4 2.52 Balance of plant 435 30.9 65.25 4.635 Transportation 79 6.2 11.85 0.93 Decommissioning and recycling 64 4.7 9.6 0.705 Total 2253 161.3 338 GJ 24.195 Tons CO2  Based on table 3, the energy required and CO2 produced for a 150kWh VRB unit is in the range of 340GJ and 24 tons CO2. Based on an 11MWh annual energy consumption [16] and 11,450 pounds CO2 annual production from passenger vehicles [17], the construction of the VRB requires almost enough power to supply nine homes and produces enough CO2 to run five cars for a year.   17 5.0  COMPARISON OF ENERGY STORAGE TECHNOLGIES After assessing the economic, environmental and social impacts of FES and VRB technologies, the costs and social/environmental implications ofeach technology are very similar. Table 4 summarizes some of the key differences of the two technologies.  Table 5: Comparison of FES and VRB Technologies  FES VRB Energy Density 50-190Wh/kg 20-30Wh/L Short term round Trip Efficiency 90% 45% Long term round trip efficiency ~0%* ~45%** Up front Capital Costs for (150kW, 150kWh unit) $165,000 $185,000 Scalability Requires additional units Easily implemented retrofits available *Since the flywheel is constantly fighting some form of friction, most of the energy in a flywheel will be consumed in anything over a dozen hours **As long as the electrolytic solutions remain in storage tanks they will not discharge  Since one of the SUB’s goals is to achieve net-zero power consumption, the renewable energy sources are expected to be added after the building is first constructed. It is important that the technology is easily scalable, does not take up too large a space, can store energy for durations of days (instead of hours) and reasonability priced.  Energy density of FES is much higher than that of VRB, however the actual space required to house the two systems would be quite similar. Both systems require a dedicated basement or room to be housed as a safety precaution (and neither is too large that it would not fit in a reasonably sized storage space). Flywheels do excel in short term round trip efficiencies, however if the energy is ever to be stored for periods longer than a   18 few hours that efficiency decays to below that of VRB and eventually approaches 0% if enough time passes. Up front capital costs are similar, VRB has a larger maintenance cost due to cell refurbishment, however this is offsetting by the ease of increasing energy storage capacity (which would be required if the SUB were to become self sufficient in its energy production). In a FES system, additional flywheel units would be required to increase the energy capacity and to increase the power capacity the flywheels would need to rotate even faster – requiring more expensive materials in the system. VRB systems can easily increase energy capacity by retrofitting the unit with additional storage tanks and electrolyte. Power capacity can be increased by retrofitting VRB systems with additional PEM cells.    19 6.0  CONCLUSION AND RECOMMENDATIONS This report investigated two potential solutions for energy storage in the new SUB - flywheel energy storage and vanadium redox flow batteries. Initial analysis of the new SUB designs determined the amount of power and energy that would be required as well as the amount of power and energy that could potentially be produced using a solar panel array. Annual energy consumption is estimated to be 1864 MWh with a potential production of 320 MWh. Despite the net energy deficit energy storage will still be needed for the SUB to achieve LEED Platinum certification and for additional future generation capacity. A triple bottom line assessment of both FES and VRB systems with special attention to the scalability and practicality of each system was performed. This report’s findings conclude that that both FES and VRB systems are ideal for use in load leveling/power quality applications such as that of the new SUB. Each technology has a relatively small environmental footprint and an indirect positive social impact by encouraging the use of renewable power supplies.  However, the length of energy storage is quite short FES systems, on the scale of a few minutes to a few hours. Conversely, VRB systems can stored on the scale of hours to days.  Due to the short energy storage time for FES systems and difficulty in scaling the units (additional units must be installed if there is an increased need for energy storage) a VRB system would be recommended for meeting the storage requirements for the SUB. In addition, further research into reducing the building’s energy load (with focus on effective heating, cooling and domestic hot water) as well as the possible increase of renewable generation capacity is needed. If surplus energy is not available for storage for a reasonable proportion of the year, an energy storage system is not a worthwhile investment.   20 REFERENCES [1] Halsall Modeling, “UBC Student Union Building – Jenga Scheme & Strategies Review,” HBBH + BH. Vancouver, BC, Rep. 2010. [2] "Statistics: Vancouver Harbour, BC, Canada - The Weather Network," [Online document], [cited 2010 Oct 21], Available HTTP: http://www.theweathernetwork.com/statistics/summary/cl1108446 [3] Bolund et al. (2007). Flywheel energy and power storage systems, Renewable and Sustainable Energy Reviews, Volume 11, Issue 2, February 2007, Pages 235-258, from http://www.sciencedirect.com/science/article/B6VMY-4FM0MS3- 2/2/03c0a30f2ba4546721097bba928facf5. [4] Liu and Jiang. (2007). Flywheel energy storage--An upswing technology for energy sustainability, Energy and Buildings, Volume 39, Issue 5, May 2007, Pages 599-604, from http://www.sciencedirect.com/science/article/B6V2V-4MG6P8C- 1/2/8ddddc379cd90095999cafce02fe0e1b. [5] Vere. (2007). A Premire Technology: Not a lot of noise, but lost of buzz, from http://www.distributedenergy.com/may-june-2007/primer-flywheel-technology-2.aspx. [6] Collins et al. (2003). Flywheel Energy Storage: An Alternative For Uninterruptive Power Sully Systems, 2003. from http://www1.eere.energy.gov/femp/pdfs/fta_flywheel.pdf. [7] Ruddel. (2000). Investigation on Storage Technologies for Intermittent Renewable Energies: Evaluation and recommended R&D strategy, from http://www.itpower.co.uk/investire/pdfs/flywheelrep.pdf. [8] Werfel et al. (2007).  A Compact HTS 5 kWh/250 kW flywheel energy storage system, IEEE Transactions on Applied Superconductivity, v 17, n 2, p 2138-2141, June 2007, from http://www.engineeringvillage2.org/controller/servlet/Controller?SEARCHID= 153b2cb12bc2e81e2cM3c4cprod2data2&CID=expertSearchAbstractFormat&DOCIN DEX=56&database=2105345&format=expertSearchAbstractFormat. [9] Garcia et al. (2006). Round Trip Energy Efficiency of NASA Glenn Regenerative Fuel Cell System, 2006, from http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/ 20060008706_2006006323.pdf. [10] Steel Construction Manual, 8th Edition, second revised edition, American Institute of Steel Construction, 1986, ch. 1 pages 1–5. [11] Cellstrom l. (2010). FB10/100 Technical Description, Feb. 2009. Retrieved October 10th, 2010, from www.cellstrom.com. [12] Holzman. (2007). The Vanadium Advantage: Flow Batteries Put Wind Energy in the Bank, Environmental Health Perspectives, 2007 July, pp A358-A361. Retrieved October 10th, 2010, from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1913571/. [13] Eckroad. (2006). Redox Flow Batteries: An In-Depth Analysis. Electric Power Research Institute, from http://my.epri.com/portal/server.pt?space= CommunityPage&cached=true&parentname=ObjMgr&parentid=2&control=SetComm unity&CommunityID=405. [14] Joerissen Ludwig et al. (2004). Possible use of vanadium redox-flow batteries for   21 energy storage in small grids and stand-alone photovoltaic systems, Journal of Power Sources 127 March 10, 2004, 98-104, from http://www.sciencedirect.com/science/ article/B6TH1-4BKPT4B-1/2/e3eb393616490c3b5b74003149f5fbd0. [15] Denholm, Kulcinski. (2004). Life cycle energy requirements and greenhouse gas emissions from large scale energy storage systems. Energy Conversion & Management 45 2153-2172, http://www.sciencedirect.com/science/article/B6V2P-4B5B98S- 2/2/3957c37b835d0d3484b01c851e149f5e. [16] U.S. Energy Information Administration. (2010). Frequently asked question – Electricity. Retrieved October 10, 2010, from http://www.eia.doe.gov/ask/ electricity_faqs.asp. [17] U.S. Energy Information Administration. (2010). Frequently asked question – Electricity. Retrieved October 10, 2010, from http://www.eia.doe.gov/ask/ electricity_faqs.asp.    22 APPENDIX: Figure Sources Table A: Average Daily Energy and Power Month  Daily Energy  Production (kWh)  Daily Power  Production  Sept  1086 kWh  85.77 kW  Oct  682 kWh  63.21 kW  Nov  349 kWh  37.62 kW  Dec  306 kWh  36.67 kW  Jan  327 kWh  37.60 kW  Feb  464 kWh  46.50 kW  Mar  731 kWh  61.60 kW  Apr  993 kWh  72.25 kW  May  1261 kWh  82.86 kW  Jun  1250 kWh  77.61 kW  Jul  1610 kWh  102.26 kW  Aug  1462 kWh  102.15 kW   Table B: Breakdown of Average Daily Energy Consumption Month  Lighting  (kWh)  Plug  Load  (kWh)  Space  Heating  (kWh)  Space  Cooling  (kWh)  Pumps  (kWh)  Fans  (kWh)  DHW  (kWh)  Daily Energy  Demand  (kWh)  Sept  462.0  1711.9  268.7243 346.5753 91.58513 545.9883  1409.002 4836  Oct  735.4  1711.9  679.7145 0  91.58513 545.9883  1409.002 5174  Nov  1436.4  1711.9  1043.283 0  91.58513 545.9883  1409.002 6238  Dec  1641.6  1711.9  1289.877 0  91.58513 545.9883  1409.002 6690  Jan  1532.2  1711.9  1305.684 0  91.58513 545.9883  1409.002 6596  Feb  1081.5  1711.9  1087.543 0  91.58513 545.9883  1409.002 5928  Mar  686.0  1711.9  1030.637 0  91.58513 545.9883  1409.002 5475  Apr  505.1  1711.9  765.074  0  91.58513 545.9883  1409.002 5029  May  398.0  570.6  477.3809 115.5251 30.52838 181.9961  469.6673 2244  Jun  401.4  570.6  221.3024 924.2009 30.52838 181.9961  469.6673 2800  Jul  311.6  570.6  82.19803 3234.703 30.52838 181.9961  469.6673 4881  Aug  343.0  570.6  66.39072 3696.804 30.52838 181.9961  469.6673 5359  Average  794.5  1331.5  693.2  693.2  71.2  424.7  1095.9  5104.1     23 Table C: Average Daily Energy Production to Consumption Ratio and Average  Daily Power Usage Month  Daily Energy Production  (kWh)  Daily Energy  Demand (kWh)  Production/Demand (%)  Daily Power  (kW)  Sept  1086  4836  22.5%  201  Oct  682  5174  13.2%  216  Nov  349  6238  5.6%  260  Dec  306  6690  4.6%  279  Jan  327  6596  5.0%  275  Feb  464  5928  7.8%  247  Mar  731  5475  13.4%  228  Apr  993  5029  19.7%  210  May  1261  2244  56.2%  93  Jun  1250  2800  44.6%  117  Jul  1610  4881  33.0%  203  Aug  1462  5359  27.3%  223        Average Daily Power (kW)  213  

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