Published in September 2017, Renewable Energy Zone (REZ) Transmission Planning Process: A Guidebook for Practitioners is designed to help streamline efforts to scale up renewable energy deployment.

Renewable Energy Zone Transmission Planning: Connecting to a Clean Energy Future

By Climatelinks

USAID and the National Renewable Energy Laboratory have partnered to transfer lessons from Texas state's expansion into wind energy to improve transmission planning by integrating renewable energy deployment and transmission system expansion in developing countries. Energy sectors around the world are taking an increasingly strategic approach to identifying optimal renewable energy resources to overcome transmission and finance obstacles, and maximize development benefits.

For policy makers and planners focused on ramping up renewable energy deployment to meet their energy sector goals, transmission expansion can be one of the biggest obstacles.

Renewable energy expansion plans are often stymied by lack of existing transmission infrastructure. Traditional transmission planning processes tend to be cumbersome, with timelines that don’t align with fast-tracked renewable energy projects. Whereas developing and building wind and solar generation projects can take as little as one to two years, adding new transmission lines to reach the often remote, solar or wind-rich generation sites can take upwards of five to ten years.

This creates a dilemma for renewable energy deployment: developers need financing to develop and build their projects, but investors require proof of existing or planned transmission near generation sites to ensure the proposed plant will be connected to the grid, fully utilized, and profitable.

To streamline clean energy development, policymakers, planners and system operators are adopting a proactive renewable energy zone transmission planning process pioneered in Texas.

A renewable energy zone is a geographic area with high-quality renewable resources, suitable topography and demonstrated developer interest―all of which support cost-effective, grid-connected, renewable energy development. The renewable energy zone transmission planning process is an approach to plan, approve, and build transmission infrastructure that connects renewable energy zones to the transmission system.   


The Renewable Energy Zone Transmission Planning Process.

Published in September, Renewable Energy Zone (REZ) Transmission Planning Process: A Guidebook for Practitioners is a new resource from USAID and the National Renewable Energy Laboratory that presents a framework for integrating renewable energy deployment and transmission system expansion.

The planning process is designed to increase the share of solar, wind and other renewable energy resources in the power system while maximizing reliability and cost-effectiveness. Transmission system expansion and upgrades facilitated by this process enable the system to harness the best and most promising renewable energy resources at the lowest possible cost.

In addition to connecting high-capacity-factor renewable electricity generation sites, these transmission infrastructure enhancements can reduce potential curtailment resulting from congestion, helping system operators to load transmission lines more efficiently.

Focused on large-scale wind and solar resources that can be developed in zones with sufficient quantities to warrant transmission system expansion and upgrades, the six-step renewable energy zone transmission planning process is based on the Competitive Renewable Energy Zones initiative that Texas launched in 2005, which resulted in the addition of 2,400 line miles of new transmission and more than 18 gigawatts of interconnected wind power within a decade. This new transmission helped increase wind power’s share in the state’s generation mix from less than 1% in 2001 to 10% in 2015. In addition to lowering congestion and curtailment, the system upgrades also opened up the most productive wind areas for electricity generation in Texas.

The Texas experience and the Renewable Energy Zone Process were highlighted in the Transmission Planning for a High Renewable Energy Future: Lessons from the Texas Competitive Renewable Energy Zones Process webinar hosted by The Clean Energy Solutions Center in partnership with the Electric Reliability Council of Texas and the GreeningTheGrid toolkit, a USAID and National Renewable Energy Laboratory collaboration designed to support integrating renewable energy into countries’ power systems.


The Competitive Renewable Energy Zone Process identified mapped out new transmission infrastructure necessary to access each REZ.

Additional Resources

Greening the Grid Webinar: Implementing Renewable Energy Zones for Integrated Transmission and Generation Planning

Adaptation, Energy
Strategic Objective
Clean Energy, Grid Integration, Mitigation, Partnership



Climatelinks is a global knowledge portal for USAID staff, implementing partners, and the broader community working at the intersection of climate change and international development. The portal curates and archives technical guidance and knowledge related to USAID’s work to help countries mitigate and adapt to climate change. 

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