Achieving a High Renewable Electricity Future

By Morgan Bazilian, Joint Institute for Strategic Energy Analysis, U.S. National Renewable Energy Laboratory
January 2014

As deployment of renewable sources of electricity gains traction, technical, economic, social, and environmental questions arise about renewable electricity’s role and integration in power systems and the wider energy sector.

The National Renewable Energy Laboratory’s (NREL) Renewable Electricity Futures Study presents a systematic analysis of a broad range of potential renewable electricity (RE) futures for the contiguous United States based on the most detailed consideration to date of geographic, temporal, and electric system operational aspects. The study finds that renewable energy resources, accessed with today’s commercially available renewable generation technologies, could supply 80% of total U.S. electricity generation in 2050 while balancing supply and demand at the hourly level. Figure 1 presents the estimated generation capacity in 2050 by technology for a suite of exploratory scenarios with renewable penetration levels ranging from 20% (baseline) to 90%.

Figure: Installed capacity in 2050
Figure1. Installed capacity in 2050

Beyond Technology: How to Get There?

Multiple technology pathways exist to achieve a high renewable electricity future. Several countries now have penetration levels of variable generation (wind and solar) in excess of 15% of their overall power generation mix, and many jurisdictions (e.g., Spain, Portugal, Ireland, Germany, Denmark, and the U.S. state of Colorado) have experienced instantaneous penetration levels of over 50% variable generation. With these higher penetration levels of variable RE, jurisdictions have begun modifying practices that evolved in an era of large, dispatchable, central-station conventional power plants.

Three categories of issues arise in meeting the types of RE pathways: policy and regulation, markets and operations, and research and development. No distinct boundaries separate these areas, and complex interactions exist among them.

Policy and Regulation

Policy and regulatory implications of such a transformation of the power sector are significant, and will be important in procuring new RE generation, extending and improving electricity grids, and promoting greater energy efficiency and responsive demand.

Markets and Operations

Both electricity market design and power system operations will impact the power system transformation in power plant economics, power system flexibility, and generation adequacy, among others. Market and operational issues are broad, ranging from physics and fundamental power engineering, to portfolio approaches to hedge risk, to new ways of improving resource mapping and forecasting.

Research and Development

The REF study notes, “Advancements in renewable technologies, reflected by cost and performance-improvement assumptions, had the greatest impact on reducing the incremental cost of high renewable generation scenarios.” Advancing our understanding and capabilities for system-level integration, forecasting and operations, as well as “traditional” research and development (R&D) focus areas of improving technologies will be important elements of realizing a high RE future. R&D in other emerging areas of energy includes tight coupling with IT systems, cyber security, and links to other sectors such as transport, fuels and chemicals, and improved life-cycle emissions analysis.

The REF study demonstrated the resource adequacy of a largely renewable energy-based power system to meet 80% of all loads at the hourly level in the contiguous United States in the coming three to four decades. Creating an enabling environment that is effective, efficient, and adaptive to achieve such a sustainable energy future for the United States will likely require collaboration between policymakers and scientists.

Much of the necessary innovation spans numerous domains. For instance, crosscutting innovation is not always aligned with current institutional structures. New ways of looking at multi-disciplinary research under headings such as “energy systems integration” may be one useful way to meet the needs of this changing landscape – both in terms of conducting research and training new researchers.

Source: Decision-Making for High Renewable Electricity Futures in the United States, Energy Strategy Reviews (22 November 2013).