DC Microgrids
The economic case for adoption
SECURE ENERGY SOLUTIONS
Copyright 2016 Positive Energies, LLC
The New Electron Economy
Future of Civilized Progress is Based on Use of Electrons
Source: ABB – Innovations in DC Technology
EMerge Alliance © 2013
Electron Use Climbs
Of All Electricity Ever Generated – ½ Used in Last 15 Yrs.
Source: ABB – Innovations in DC Technology
EMerge Alliance © 2013
Power Conversions Take Their Toll
Efficiency, Complexity, Reliability, Cost
Source: ABB – Innovations
EMerge Alliance © 2013
DC Technology
Sources & Loads Continue Moving To DC
Power Electronics & Electronic Equip. Drive Power Architecture
Source: ABB – Innovations in DC Technology
EMerge Alliance © 2013
Current Grid Architecture
Why
Microgrids?
What is a
Microgrid?
From Smart Grid to Microgrids
Balancing the Renewable PowerEquation
Generation
Transmission
Distribution
Smart
Meters
Smart Buildings
Closing the Loop with Microgrids
Smart Homes
• Why Microgrid Energy?
• Increase renewable energy availability
• Improve, reliability & independence / security
• Improve availability in underserved markets
• Create open environment for energy innovation
Local Energy Storage
Local Generation
© 2011 EMerge Alliance
Slide Courtesy of Intel Research Labs
Zero Energy Buildings (ZEB)
Regional Grid
Public Utilities
Entire Power Network
Community
Room/Floor Layer
Sensors
Computation
Distribution Grid
Generation
Storage
Communications
Sensors
Computation
Campus
Building Layer
Generation
Storage
Communications
Building Microgrid
Generation
Storage
Communications
Sensors
Computation
MICROGRIDS
Smart Building
ENERNET
National Grid
MACROGRIDS
Smart Grid
A ZEB driven network will look much like the Internet
Room
Microgrid
Generation
Storage
Communications
Sensors & Devices
Bi‐directional power exchange
Electrical Devices
EMerge Alliance
© 201‐3
Smart Grid
Smart Building
Internet: Information Technology Convergence
A Standardized Common Platform Was Key
Words
Languages
Images
Video
Ink
Paper
Photo
Chemical
Electronic
Digital
Data Base
Mechanical
Registers
Math
Accounting
EMerge Alliance © 2013
Magnetic
Tape
Voice
Sounds
Power Technology Convergence
Solar
Fuel Cell
Non
Synchronous
DC
Non
Synchronous
DC
DC STORAGE
&
DISTRIBUTION
Non
Synchronous
AC or DC
Wind
EMerge Alliance © 2013
Synchronous
AC or DC
Turbine
Water Transport: On Board Local DC Grid
• 1000 VOLT DC Power
• 20 MW
• 20% Energy Saving
• 30% Foot Print and Weight
Reduction
http://www05.abb.com/global/scot/scot293.nsf/verity
display/b4f3f099e9d21360c1257a8a003beac2/$file/AB
B%20Generations_20%20Onboard%20DC%20grid.pdf
14
Status Quo
Common Building
Loads (80%DC)
V
DC
F
D
DC
AC
AC
DC
4% to
8% Loss
AC
4% - 8%
Typical
Conversion
Loss
2% to 10%
loss
DC
AC
12% to
20% loss
DC
AC
AC
15% to
20% loss
DC
AC Bus
AC
4% to
8% Loss
DC
AC
3% to 10%
loss
DC storage
AC
DC
4% to
8% Loss
AC Grid
DC Microgrid Technology
A Better Way
DC / Semiconductor
Based Loads
DC
V
F
DC
2% to 5%
loss
0% loss
D
DC
AC
2% to 5%
loss
DC
3% to 6%
loss
DC Bus
3% to 5%
loss
DC
DC
AC
DC
3% to 6%
loss
DC
AC
1% to 5%
DC
DC
loss
DC storage
0% to 2%
loss
AC Grid
• Higher Efficiency
• Minimal Conversion Loss
• Lower Operating Expense
• Safer
• Fewer Components
• More Reliable
• Less Real Estate
• Reduced Carbon Footprint
380V DC as Microgrid Backbone
• 380V DC power bus as the common aggregation for multiple energy
sources
• Grid AC power converted to 380V DC
• Input from larger solar arrays at 380V DC
• Potentially energy storage at 380V DC
• Distribute 380V DC across
distances, reducing cabling required
• Convert from 380V DC to 24V
DC near point-of-use
• Some major building loads, such
as lighting, can be powered by
380V DC directly
EnergySources
Solar
PV
Wind
MPPT
Wind
Cont.
Battery
Storage
Gen
Set
Fuel Cell
Other
Utility
Meter
380VDC
Converter
Facility Power Server and Common Distribution / Collector (380VDC) Bus
Lighting
Loads
24V/
380VDC
Plug
Loads
24VDC
EV
Charger
380VDC
HVAC
Loads
380VDC
Electrical Loads
Electronic
Loads
380/24VDC
Telecom
-48V /
380VDC
Data
Center
380VDC
The Eco-System for DC is rapidly Building
A
Systems
Power
Infrastructure
Peripherals
Controls
Power Servers
Cabling
Ceiling Grids
Bus Bars
Light Fixtures
A/V Equipment
Security Cameras
Window Shades
VAV Actuators
Wireless Repeaters
Motion Sensors
Occ. Sensors
Photo Sensors
Dimmers
Lighting Controls
Room Controls
Thermostats
MPPTs
Solar Arrays
Wind Turbines
Electric Generation
Electric Storage
Powered Ceiling Grid
Plug Strips
Connectors
Basic System Components
Portfolio
DC for Building Services
AC Motor applications are moving to AC/DC Variable Speed Drives
DC DRIVES MAY BE BETTER BECAUSE.
• DC drives are less complex with a
single power conversion from AC
to DC.
• DC drives are normally less
expensive for most horsepower
ratings.
• DC motors have a long tradition of
use as adjustable speed machines
and a wide range of options have
evolved for this purpose:
•Can provide a wide speed range at constant torque.
• Accessory mounting flanges & kits for feedback tachometers and encoders.
•DC regenerative drives are available for continuous regeneration for
overhauling loads. Similar AC drives are more complex and expensive.
• Properly applied brush and commutator maintenance is minimal.
• DC can provide starting & accelerating torques in excess of 400% of rating.
• AC drives may produce undesirable audible noise in some applications.
Photos courtesy of
BLDC motor use is up: higher efficiency & torque, better articulation, increasing availability.
EMerge Alliance © 2013
20
PV Manufacturer : 25 years Warranty
http://us.sunpower.com/sites/sunpower/files/media-library/data-sheets/ds-x21-series-335-345-residential-solar-panelsdatasheet.pdf
• Sun Power: 40 Years Useful Life (99 % of Modules will provide 70 % Power)
• Inverters: 10-15 years warranty
http://us.sunpower.com/sites/sunpower/files/media-library/white-papers/wp-sunpower-module-40-year-useful-life.pdf
PV and Battery Cost Reduction Leading to DC Networks
21
http://www.greentechmedia.com/articles/read/why-moores-law-doesnt-apply-to-clean-technologies?utm_source=Solar&utm_medium=Picture&utm_campaign=GTMDaily
Customer value of DC Micro/Nanogrid
• Creates a Mesh Network Power System
• Low Voltage DC is inherently safer
• Power delivery is highly distribute
• Renewable Generation feeds storage and loads allowing for optimization of size
• Stabilizes long term cost of power
• Immediate reduction in energy usage use of 20% or more
Additional Cost Considerations of Local DC Power
• More than 50% of the cost of an LED light is in the inverter
• Elimination of Power Factor
• Inverters add cost and system losses while reducing system reliability
• Based on DC, PV system cost is reduced by about 20%
• In addition to cost savings, PV systems based on DC are more reliable
• Batteries, and capacitors, store dc power. AC power increase the cost of batteries (as much
as 50% in some cases)
• DC use increases the competitiveness of manufacturing industry and saves jobs Energy cost
is as great as 33% of the operating cost of a manufacturing plant
23
Standards Organizations working to Advance DC
EMerge Alliance
© 2013
Applications of DC Microgrids
Devil’s Thumb Ranch Ecovillage
• DC Microgrid with solar, batteries, and DC transition
of loads
• Operational guest ranch in Winter Park, Colorado
• Islanded operation
Ernesto Cortissoz International Airport (BAQ)
• 2.5MM customers per year international airport in
Barranquilla, Colombia
• No grid connection because of economics
• 4MW, 3MWh battery storage
• MEGs on critical loads
C-PACE as an Enabler of DC Microgrids
• Federally supported financing program
• Assesses the potential for a cash positive energy
upgrade at a commercial facility
• No cap ex to the business owner
• Stays with the building
• Verified by an independent third party
(technically, financially)
• What can you do?