Microgrids and Integration of Clean Energy

Transcription

1 Microgrids and Integration of Clean Energy University of Pittsburgh Electric Power Industry Conference November 12, 2012 Presented by Bruce G. Campbell, P.E.

2 Microgrid Definitions A microgrid is any portion of the larger utility grid that can be intentionally isolated/islanded from the larger grid and continue supplying customer loads. Panel discussion, 2011 IEEE ISGT Conference A microgrid is a group of interconnected loads and distributed energy resources within clearly defined electrical boundaries that acts as a single controllable entity with respect to the grid. A microgrid can connect and disconnect from the grid to enable it to operate in both grid-connected or island mode. Microgrid Exchange Group, October 2010 The fundamental concept of a microgrid can be summed up this way: an integrated energy system consisting of distributed energy resources and multiple electrical loads operating as a single, autonomous grid either in parallel to or islanded from the existing utility power grid. Pike Research 2

3 Key Elements of a Microgrid Must Have Electrical Sources (*)Capable of island operation and/or parallel with grid Sources > * Electrical < Sources OR intelligence & load control* Defined PCC Isolating means* Intelligence / integrated purpose May Have Heat Sources & Heat Energy Storage Other Criteria Continuous duty (not an emergency power system) < 10 MW (?) Operated for the benefit of the customer and/or utility 3

4 Key Elements of a Microgrid 4

5 Key Elements of a Microgrid GC GC Distributed Residential LC GC GC R Customer LC BATTERY STORAGE Customer PV LC Utility Substation Islanding Breaker Microgrid Control Customer 5

6 Architecture Community/Utility Urban or rural communities Connected to utility grid Utility distribution incorporated into microgrid Variety of DER over large area Relieve demand in dense load areas Reduce blackout duration (operate in Island mode) Encourage use of Renewable Generation Defer Utility infrastructure costs Institutional/Campus 1.3 GW by 2016 CAGR = 20.3% Commercial/Industrial, Institutional/Campus, Military (Grid-Tied) High level of power quality and reliability Single facility or multi-facility site such as a shopping center or university campus. Relatively compact (geographically) Real-time power generation controls that can take advantage of price signals Demand-side management Reduce blackout duration (operate in Island mode) Remote Off-Grid, including Military Off-Grid Military Base 0.46 GW by 2016 CAGR = 35.4% Stand-alone facility, campus, or community Typically geographically isolated May be temporary / portable Source and load control coordination essential Storage can be key Source: Pike Research 6

7 Architecture Institutional/Campus 1.3 GW by 2016 CAGR = 20.3% Military Base 0.46 GW by 2016 CAGR = 35.4% Source: IEEE 7

8 Source & Load Control Islanded Isoch + Base Load ENGINE ENGINE ENGINE Storage Inverter PV Inverter NEGATIVE LOAD Advantages: Dispatch P, Q at slow speed Unsophisticated / slow communication is adequate Base Load Unit efficiency optimized Disadvantages Base Loading complex for CHP Isoch unit > short-term load (and PV & Wind) variability Requires communication and overall control(not autonomous) 8

9 Source & Load Control f (per unit) 1.0 % droop f (per unit) P (per unit) f (per unit) Droop Control 1.0 Load 1 f min Load 1 Operating Region Load 2 f min Load 2 Operating Region 1.0 P 1 +P 2 =P load Increasing Load / Decreasing Generation 0.9 Droop Control Applied to 0 P 1 P 1max P 2 P max2 P (kw) Droop Control 2 unmatched sources 9

10 Control Architecture Autonomous Simplified installation Does not rely on communications No / limited cyber security concerns Lower cost Likely relies on droop control, passive synchronization Cannot maximize economic dispatch Individual sources, protection, etc. is unaware of system status (generators, islanded or not, etc.) Master Control Allows efficient dispatch Flexible control Points in system are aware of status switch protection settings, etc. Allow reclosing only under certain conditions More complex and expensive Increased vulnerability 10

11 Summary - Opportunities / Obstacles Potential Benefits Modular - Install generation rapidly to meet load growth Capital / Infrastructure deferment Address renewables (wind, solar) Increased energy efficiency / Reduced losses Increased reliability Enhanced power quality Local energy visibility / Consumer awareness Microgrid becomes active distribution system Potential Obstacles Standards development and acceptance Policies, Regulatory Environment Engineering & design costs / lack of Plug & Play Equipment costs Equipment / technology availability Security 11

12 Microgrid Example 12

13 Utility Feeder Microgrid Residential Demand Response OR Military DSG Commercial Distributed Gen & Demand Response State Data Ctr. DSG AFRC DSG Kettle Foods Solar Actual location of Sectionalizing Breaker Original proposed location of Sectionalizing Breaker 13

14 Utility Feeder Microgrid Feeder is approximately 2.5 miles total length; distributed residential, commercial, and light industrial loads. PLC PLC PLC WAN EXISTING Distributed Generation Utility dispatched 3 customers with DG: 6 total generators totaling 5.7 MW Utility Substation Customer Islanding Breaker Distributed Residential 15 kv Feeder WAN Customer Central Control / Dispatching Customer Customer PV WAN BATTERY / INVERTER SYSTEM PLC WAN 14

15 Utility Feeder Microgrid PGE Substation Other feeders 15 kv Feeder Islanding Breaker 15kV Breaker 1000kVA 12.47kV-480V Other Transformers TOTAL OF 5 1 MVA INVERTER BLOCKS 250kVA B-Max Inverter 250kVA B-Max Inverter 250kVA B-Max Inverter 250kVA B-Max Inverter 125kW 32.25kWh Battery 125kW 32.25kWh Battery 125kW 32.25kWh Battery 125kW 32.25kWh Battery 125kW 32.25kWh Battery 125kW 32.25kWh Battery 125kW 32.25kWh Battery 125kW 32.25kWh Battery 15

16 16