Solar-Plus-Storage Analysis

For solar-plus-storage—the pairing of solar photovoltaic (PV) and energy storage technologies—NREL researchers study and quantify the unique economic and grid benefits reaped by distributed and utility-scale systems.

Much of NREL's current energy storage research is informing solar-plus-storage analysis. Energy storage plays a key role in a resilient, flexible, and low-carbon power grid. Among other benefits, it can help maintain the stability of the electric grid, shift energy from times of peak production to peak consumption, and limit spikes in energy demand. Solar-plus-storage shifts some of the solar system's output to evening and night hours and provides other grid benefits.

NREL employs a variety of analysis approaches to understand the factors that influence solar-plus-storage deployment and how solar-plus-storage will affect energy systems. This work considers both current and future scenarios and can be broadly divided into two market segments—distributed (small-to-medium systems) and utility-scale (large systems).

Distributed Solar-Plus-Storage

Just as PV systems can be installed in small-to-medium-sized installations to serve residential and commercial buildings, so too can energy storage systems—often in the form of lithium-ion batteries. NREL researchers study the benefits of such systems to property owners, their impact on the electric grid, and the effects on how buildings use electricity.

NREL's publicly available System Advisor Model and the Renewable Energy Integration and Optimization Model inform this analytical work.

Two graphs display data captured gathered from home battery systems over 24 hours. The graphs show how the batteries charge during daylight hours, then discharge during a peak period in the evening with higher energy cost, reducing the home's demand on the electric grid during this time. — One NREL study of distributed solar-plus-storage gathered real data from a housing development equipped with solar-plus-storage and compared it with modeled results. This helped the researchers to identify ideal discharge schedules and battery sizes to optimize cost- and emissions savings.

Featured Publications

Savings in Action: Lessons Learned From a Vermont Community With Solar Plus Storage, NREL Technical Report (2024)

Nova Analysis: Holistically Valuing the Contributions of Residential Efficiency, Solar and Storage, NREL Technical Report (2024)

U.S. Solar Photovoltaic System and Energy Storage Cost Benchmarks, With Minimum Sustainable Price Analysis: Q1 2023, NREL Technical Report (2023)

Savings in Action: Lessons From Observed and Modeled Residential Solar Plus Storage Systems

Savings in Action NREL Technical Report (2022)

Savings in Action NREL Fact Sheet (2022)

Savings in Action NREL Presentation (2022)

Assessing the New Home Market Opportunity: Case Study and Cost Modeling for Solar and Storage in 2030

Assessing the New Home Market Opportunity NREL Technical Report (2022)

Assessing the New Home Market Opportunity NREL Fact Sheet (2022)

Assessing the New Home Market Opportunity NREL Presentation (2022)

Contact

Renewable Energy Policy and Market Analyst

Jeff.Cook@nrel.gov

Utility-Scale Solar-Plus-Storage

Energy storage has become an increasingly common component of utility-scale solar energy systems in the United States. Much of NREL's analysis for this market segment focuses on the grid impacts of solar-plus-storage systems, though costs and benefits are also frequently considered.

Two graphs show how energy can be charged and discharged, hour-by-hour, from a large battery and solar system over 24 hours. The left graph loses some energy to inverter clipping due to its configuration, which the right graph avoids. — NREL researchers developed an open-source model to optimize energy storage operation for utility-scale solar-plus-storage systems in both alternating-current-coupled (left) and direct-current-coupled (right) configurations. Here the model was able to demonstrate how the direct-current-coupled battery eliminated the clipping events, and thereby energy loss.

Featured Publications

U.S. Solar Photovoltaic System and Energy Storage Cost Benchmarks, With Minimum Sustainable Price Analysis: Q1 2023, NREL Technical Report (2023)

Exploring The Design Space of PV-Plus-Battery System Configurations Under Evolving Grid Conditions, Applied Energy (2022)

The Evolving Energy and Capacity Value of PV+Battery Hybrid System Architectures, Advances in Applied Energy (2021)

Contact

Principal Energy Analyst

Paul.Denholm@nrel.gov

Storage Futures Study

The Storage Futures Study considered when and where a range of storage technologies are cost-competitive, depending on how they're operated and what services they provide for the grid.