NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable Energy, LLC.

The role of smarter grids in 

variable renewable resource 

integration

Mackay Miller, Research Analyst

National Renewable Energy Laboratory

World Renewable Energy Forum

May 13-17, 2012

Denver, Colorado

Mackay.Miller@nrel.gov

NREL/PR-6A20-55090
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This presentation contains material and 

findings from a forthcoming International 

Smart Grid Acton Network (ISGAN) white 

paper: Smart Grid Contributions to 

Variable Renewable Resource 

Integration, co-written by Mackay Miller 

(NREL) and David Beauvais (Natural 

Resources Canada), and currently in 

review. 

Smart Grids and VRR Integration

Disclaimer

The ISGAN white papers are meant as inputs into the broader ISGAN dialogue. The findings, 

analysis, and opinions expressed therein are those of the listed authors only. 

www.iea-isgan.org
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Mitigating Specific Integration Challenges 

 Transmission

 Magnitude of hourly overall ramping requirements

 Regulation capacity and intra-hour variability

 Overgeneration

 Large, near-instantaneous production ramps

System Integration

Demand- and delivery-side intelligence

Activating markets

Enabling distributed generation and microgrids

DSO and TSO intelligence and coordination

Control room improvements

Key SG Contributions to VRR Integration
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1: Ensure alignment between smart grid roadmaps and 

scenarios for future renewable energy supply

VRR generation targets; Projected geographical distribution; Mix 

of distributed vs. utility-scale; Efficiency targets 

2: Evaluate smart grid VRR integration solutions in the 

context of the full range of integration solutions

Other tools are context specific, and include market reforms, 

system operation changes, conventional generator cycling

Key Planning Concepts
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 Transmission

Wide-Area Situational Awareness; Phasor Measurement Units; High-Voltage 

DC Transmission; Flexible AC Transmission Systems

 Magnitude of hourly overall ramping requirements

Industrial & agricultural load resources -- e.g. agricultural water pumping; 

industrial refrigeration, wastewater storage pumping

 Regulation capacity and intra-hour variability

Fast or instantaneous industrial, commercial, and residential load resources –

e.g. lighting, HVAC, water pumping with storage

 Overgeneration

Industrial, commercial & residential load resources -- e.g. municipal water 

storage pumping, thermal mass pre-cooling, PHEV charging

 Large, near-instantaneous production ramps

Volt & var optimization systems, distribution automation, active power 

electronics

Mitigating Specific Integration Challenges

Sources: Kiliccote et al, 2010; Neal & Bravo, 2011
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 SG solutions may be cost-effective in many contexts

 The relative economics of the integration solution set is gridspecific, geography-specific, and seasonal

 The economics of the demand response “supply curve” is gridspecific and seasonal, and changes over time

 SG solutions may require complementary market- and/or system 

operation changes

 Projected characteristics of VRR capacity and generation should 

inform SG planning and investment

SG in the context of other integration tools