Close to the Metal Dense Area EVSE Network Considerations and - - PowerPoint PPT Presentation

Close to the Metal

Dense Area EVSE Network Considerations and Constraints

Dorrier Coleman TEQ Charging

• Smart charging interface for all chargers
• ”Time based multiplexing” optimization of charging
• Listening to user’s charging requirements and providing

decision making information and charging sessions seamlessly

Who We Are

Dorrier Coleman CTO, TEQ BSCmpE Georgia Tech

Intelligent EV Charging

Why This Is Useful

• Anecdotal traction in the MFH and Workplace spaces
• Result of significant cooperation with building managers, owners, and

electricians

• Multiple technologies in many kinds of buildings

Defining Dense Area for EV Network Design

Infrastructure

• Large structures
• High population densities
• Limited parking
• Many EV’s per parking area

Economics

• High land values
• Pressure on revenue performance for

space use and improvements Image source: Wikimedia Foundation

Pressing Issues to Address*

Apartment and Workplace Infrastructure Costs Reliability

Killing installations with high price tags and few means of control From is it available to is it broken, the status of a lot of infrastructure is unknown Unique challenges and unfulfilled stakeholders make for slow growth

*Shamelessly stolen from Jun 2018 EPRI Survey

Pilot Report

• 32 Pilots
• 3 phases
• Hotels, Apartments, Workplaces
• Access Control
• Payment
• Power Management
• Web based driver and owner interaction

Pilot Phase 1 example: Small Office

• 4 Story building
• Built in the 60’s
• Very short distance from power panel to chargers
• System able to use Wifi, Zigbee, Ethernet, CAN, Modbus
• Unable to get consistent wireless connection
• Forced to fall back on ethernet due to rf properties of walls and ceilings
• Cat 5e pulls very expensive

Pilot Phase 2 Example: B&B

• 3 Story building
• Built in the 1910’s
• Mixed brick and stonework, very thick wooden ceilings and floors
• System used cellular modem and controls transformers
• Avoiding penetrations and separate communication conduit successfully

controlled installation costs

• Very robust system, but very bulky

Pilot Phase 3 Example: Large Apartments

• 6 Story building, mixed use
• Built 2000’s
• Challenging cellular environment
• Substantial length and width to building
• System used cellular modem, CAN

communication

• Challenging RF environment overcome

with larger antennae

• Multiple cellular modems placed to avoid

very long control wire runs

The Building

• Difficult Penetrations
• Long Pulls
• Little Panel Space
• Poor RF environments

Notes on Sources of Cost

Two communications strategies: wireless and wired Key factors in common:

• Distance
• Number of Penetrations
• Construction Materials

Image Source: Wikimedia Foundation

A Microeconomics of EVSE Growth

• 1. Commercial property owners are motivated by payback period

(They probably don’t use discounted payback period)

PP = EVSE Price + Installation + Setup Charging Revenue - (Electricity costs + Operator fees)

• 2. PP <= 2 yrs

The Urban Market Distribution

Install Cost - 2* Annual Revenue Stream = 0 Or PP <=2 In other words, the harder installation is the fewer buildings will buy

Commercial Property

• Ugly Install Region
• Older buildings tend to

be harder to penetrate due to construction techniques.

New Construction Issues

• New construction

is getting larger

• This trend tends to

complicate costs

New Construction Issues

• Signal loss is higher in thermally efficient construction

“Experimental results, such as those collated in Report ITU-R P.2346, shows that, when characterised in terms of entry loss,

buildings fall into two distinct populations: where modern, thermally-efficient building methods are used (metallised glass, foil-backed panels) building entry loss is generally significantly higher than for ‘traditional’ buildings without such materials. The model therefore gives predictions for these two cases.” -ITU Rec. P. 2109-0 (06/2017)

• Thermal barriers likely to exist around interface between building interior and

parking

Multifamily Housing

• MFH also tends to be
• lder

Source: 2000 US Census

MFH New Construction

• MFH construction is

trending towards larger Buildings. Source: US Census Bureau

But is this relevant?

• Is cost just a manufacturer and installer concern?

○ There are path dependency and network effects that make guidance critical

• Stakeholder input is needed now.

○ Installations are cost intensive and therefore very “sticky” ○ (Economic) utility is distributed among many parties, not all of whom are involved in every buying decision ○ Marginal cost of additional utility is very low before install and very high after ○ Substantial danger of becoming locked into sub-optimal path dependent possibilities

• Standards need to be physical layer agnostic but physical layer considerate

Local Charger Network Model

Cellular Data The Internet Interfaces ISP’s Utility DR Networks Local Links EV Telematics User devices BMS Other automation (lights, etc.) Wifi <GHz radio EVSE proprietary Ethernet EVSE EV

Kinds of Communications and Constraints

Requirement Bandwidth requirement Latency requirement Equipment Status Reporting Low Medium Demand Response Low High Access control/payment Low High Charge Session Telemetry High Low

Site Local Network Resources

EVSE / Operator Site Infrastructure User

• Wifi
• Ethernet
• ModBus
• CAN
• Grid Demand

Response

• Sub-GHz Radio
• EV Telematics
• User cell phone
• Cellular Modems

(LTE-M especially)

• Sub-GHz Radio
• Bluetooth
• New Com. Wire

Potential Directions for Standards

• Differentiate between high bandwidth and low bandwidth interactions. Keep

high bandwidth interactions off the local charger network where bandwidth is expensive.

• Differentiate between time sensitive and time insensitive interactions. Allow

time insensitive interactions to take place over links that aren’t guaranteed to be connected.

• “Yes and” is critical. The cost effective way to implement a local charging

network is as diverse as the buildings themselves.