Making high-quality, high-power solar cells and modules using U.S.-based technology at affordable costs to address the world s energy needs DC MICROGRIDS A SOLAR BACK TO THE FUTURE SOL HAROON, LEAD SYSTEMS ENGINEER, SOL@SUNIVA.COM DECEMBER 2012
AGENDA 1. Overview of Suniva 2. Overview of PV Distributed Energy System Types 3. What is a Microgrid? 4. The Current Wars 5. What is a DC Microgrid? 6. Savings from a DC Microgrid 7. Examples of DC Microgrid 8. Case study of a Residential DC Microgrid 9. References 2 Confidential & Proprietary Suniva, Inc. 2012
SUNIVA -OVERVIEW Manufacturer of high-efficiency crystalline silicon PV cells and modules High-Efficiency Cells: 19% in production now; over 20% in laboratory; roadmap to over 22% by 2014 High-Power Modules: Up to 16+% in production; modules ranging from 235-315 watt Buy American Compliant: Our Buy American compliant modules are one of the highest U.S.-content modules on the market Market focus: Commercial and utility applications in the U.S., Asia and Europe Top-Tier Customers: Solar City, Pro Logis, Sunetric, Fonroche, Reliance, Inman Solar, Orion, AGT, UPS Manufacturing Capacity: 170 MW in the U.S.; 400 MW in Asia Cost Competitiveness: Cost competitive with top-tier Asian manufacturers Headquarters: Norcross, Georgia (suburb of Atlanta) Incorporated: 2007; Spun-out from Georgia Tech s UCEP PV Center Employees: Approximately 200 3 Confidential & Proprietary Suniva, Inc. 2012
1985: PV Program Established at Georgia Tech Department of Energy provided funding 1992: University Center of Excellence Established 2007: Suniva Founded 90 kw rooftop installation on Georgia Tech s Clough Center, Atlanta, Georgia Deep Roots, Continued Collaboration 4 Confidential & Proprietary Suniva, Inc. 2012
SUNIVA INNOVATION IN THE VALUE CHAIN The solar cell is the DNA of any PV system, and hence the key driver of value Silicon Ingot Wafer Cells Modules Balance of System Solutions Systems Integrators Unique Partnerships 5 Confidential & Proprietary Suniva, Inc. 2012
BALANCE OF SYSTEMS SOLUTIONS Suniva partners with the best-in-class inverter, mounting and battery storage/charge controller companies to streamline the balance of system selection process. Mounting Inverters Improve overall PV system performance Maximize kilowatt hours produced 6 Batteries (Storage) Reduce cost of PV ownership ARRA compliant Confidential & Proprietary Suniva, Inc. 2012
DISTRIBUTED ENERGY: PV SYSTEM TYPES FOUR TYPES of SYSTEMS Standard Gridtie System [1] Grid-tie ( on-grid ) direct-power [2] Off-grid battery-based [3] Grid-tie ( on-grid ) battery back up [4] Off-grid direct-power 7
DISTRIBUTED ENERGY: PV SYSTEM TYPES Standard Off-Grid System Courtesy of Home Power Magazine 8 Confidential & Proprietary Suniva, Inc. 2012
DISTRIBUTED ENERGY: PV SYSTEM TYPES Gridtie with Battery Backup Courtesy of Home Power Magazine 9
SO JUSTWHATISAMICROGRID? A microgrid is a localized grouping of electricity sources and loads that normally operates connected to and synchronous with the traditional centralized grid (macrogrid), but can disconnect and function autonomously as physical and/or economic conditions dictate. A microgrid offers independence and profitability 10
TYPE OF DC MICROGRIDS 11
MICROGRIDS AND SMART GRIDS 1 Generation 2 Distribution 3 Storage 4 Loads 5 Control, management, and monitoring 12
TYPES OF MICROGRIDS 13
THE CURRENT WARS Courtesy of Emerge Alliance 14
THE CASE FOR A DC MICROGRID Many smart loads today are DC. Most renewable distributed power generation today is DC. Ergo use a DC backbone to connect the two. Potential energy savings between 10% to 30%. Energy Secretary Steven Chu: America cannot build a 21st Century energy economy with a mid-20 th century electricity system 15
A DC MICROGRID CONSORTIUM 16
THE CASE FOR A DC MICROGRID A DC microgrid is a microgrid that can co-exist with an AC power network but is based on DC power. Such a microgrid enables smart DC loads and enables the feed-in of distributed renewable energy running natively in DC. Advantages: Enables smart DC loads to run with native power. Synchronization of distributed generators are not necessary. Ability to use distributed renewable energy sources that natively generated DC such as PV. The ability to use Class 2 NEC (National Electric Code) loads at non-lethal voltages (e.g. 24V). No power factor losses. Loads are not affected by voltage sag, voltage swell, three-phase voltage unbalance, and voltage harmonics. No inverter or transformer losses DC-DC switching regulators can hit high efficiencies if required for certain loads Higher efficiency than AC microgrids also resulting in less thermal/heat wastage 17
DC MICROGRIDS WITHIN BUILDINGS 18
DC AND EFFICIENCY Yale School of Forestry and Environmental Studies Reference: http://www.reilproject.org/05-dc-microgrids%20%281%29.pdf 19
DC AND EFFICIENCY 20
DC MICROGRID STANDARDS 21
DC MICROGRIDBUILDING DISTRIBUTION 22
WORLDWIDE EXAMPLES OF DC MICROGRIDS 23 Courtesy of EPRI (electric power research institute)
EXAMPLE: DUKE ENERGY 380VDC DATA CENTER 24 Courtesy of EPRI (electric power research institute)
EXAMPLE: DUKE ENERGY 380VDC DATA CENTER 25 Courtesy of EPRI (electric power research institute)
WHY 380V 26 Courtesy of EPRI (electric power research institute)
24V DC DISTRIBUTION NexTek Power and other companies are creating smart 24V DC distribution systems. NEC Class 2 recognized. Under the 50V threshold. Individual loads/devices typically consume 100W or less power yet deliver the same performance as older traditional devices 27
CASE STUDY: RESIDENTIAL DC MICROGRID A ~2000 square foot house Currently 6 Suniva 255 panels for around 1500W of PV. Expanding to 2000W and then to 4000W of PV 12,000 WH of storage (4 GS Battery 246 AH 12V batteries arranged as 2S/2P for 24V) All lighting to be replaced with solid state lighting 28
CASE STUDY: RESIDENTIAL DC MICROGRID Type of lighting: Lighting by Lighting Energy Depot http://www.lightingenergydepot.com/ 29
CASE STUDY: RESIDENTIAL DC MICROGRID Around 50W per room (15 x 20 feet room size) was needed to provide abundant illumination. Efficiency around 90 lumens per W Smart loads such as laptops and entertainment systems on DC Further studies are being done to log energy usage and generation 30
FURTHER DEVELOPMENTS Standards continue to evolve as more vendors offer product and services Smarter Grids, More Distributed Energy, Smarter Loads Questions? 31
REFERENCES >EmergeAlliance: http://www.emergealliance.org/resources/presentations.aspx >NexTek Power Design Guide: http://www.nextekpower.com/support/design_guide_06-16-11.pdf >Rebus specification: http://rebuspower.com/rebus%20microgrid%20specification%20v0_ 14.pdf >REIL: DC Microgrids: Benefits and Barriers http://www.reilproject.org/05-dc-microgrids%20%281%29.pdf >EPRI Microgrids in General: http://disgen.epri.com/downloads/15-definingmicrogrids.pdf 32
THANK YOU! I'd put my money on the sun and solar energy. What a source of power! I hope we don't have to wait until oil and coal run out before we tackle that. -Edison 33