The U.S. solar industry has seen significant shifts in recent years, with trends pointing toward larger system sizes, higher module efficiencies, and a steady rise in paired PV+ storage systems.

According to the “Tracking the Sun 2024” report by Lawrence Berkeley National Laboratory, the prices of residential solar systems have consistently dropped by approximately $0.1 to $0.2 per watt (W) annually, driven primarily by reductions in soft costs. In 2023, the median installed price for residential systems fell by around $0.1/W in real (inflation-adjusted) terms. This decline occurred despite inflationary pressures that have affected many other sectors of the economy.

In contrast, the report notes a significant shift in the non-residential sector, where median installed prices increased for the first time in 15 years, rising by $0.1 to $0.2/W. This increase is attributed to inflation and supply chain disruptions, which have had a delayed impact on non-residential projects, given their typically longer development timelines. The report suggests that while inflation has exerted upward pressure on costs, the PV sector has so far managed to mitigate these effects better than many other industries.

Rising System Sizes and Module Efficiencies

One of the most notable trends is the continuous increase in system sizes for residential PV installations. The median residential system size reached 7.4 kW in 2023, up from much smaller sizes seen two decades ago. This growth is largely due to declining costs, which have made larger systems more affordable, and improvements in module efficiency, which allow for greater energy generation within the same physical footprint.

The increase in module efficiencies is another key driver behind this trend. The report attributes efficiency gains to the growing dominance of mono-crystalline modules and ongoing innovations in cell architecture, such as Passivated Emitter and Rear Cell (PERC) technology and Tunnel Oxide Passivated Contact (TOPCon) technology. These advancements have not only increased the energy yield per square foot but have also enabled reductions in balance-of-system (BoS) costs, which include components like inverters and mounting structures.

The report points out that the correlation between rising system sizes and module efficiency since 2010 suggests that efficiency improvements are a primary factor driving the growth in system sizes, particularly in residential settings where roof space is often limited.

PV+Storage Systems

The adoption of paired PV+storage systems has been another significant development in the distributed solar market. The report reveals that storage attachment rates have been steadily increasing, with 12% of residential and 8% of non-residential systems installed in 2023 incorporating battery storage. Hawaii leads the nation in this trend, with nearly all new PV installations in the state, including storage, driven by regulatory changes that incentivize self-consumption over grid exports.

California’s recent shift from Net Energy Metering (NEM) to a Net Billing Tariff (NBT) structure has profoundly impacted storage adoption. The NBT structure, which offers lower compensation for electricity exported to the grid, has created a strong financial incentive for consumers to install battery storage to maximize self-consumption. As a result, storage attachment rates for residential systems under the NBT regime have surged to approximately 60%, compared to just 10% under the previous NEM structure. This trend indicates that policy changes can significantly influence market behavior and accelerate the adoption of new technologies like battery storage.

Customer Segmentation and Market Dynamics

The report provides a detailed analysis of customer segmentation in the U.S. solar market, revealing that residential PV systems are overwhelmingly installed on detached single-family homes. Other residential installations are found on small multi-family buildings, condos, townhomes, and mobile homes, representing a small fraction of the market.

The report identifies commercial buildings and agricultural properties as the primary sites for PV installations in the non-residential sector. Approximately half of non-residential systems are installed on commercial properties, while one-third are on agricultural land. The remaining installations are by tax-exempt customers, such as schools, government buildings, and houses of worship. The report highlights that system sizes vary significantly across these segments, with the largest installations typically found in school and government facilities. In contrast, agricultural systems are much smaller, often in the 10-20 kW range.

Third-Party Ownership Trends

Third-party ownership (TPO) models, which include leases and power purchase agreements (PPAs), have historically played a significant role in the U.S. solar market. However, the report notes a decline in TPO’s share of residential installations since its peak at around 60% in 2012. In 2023, TPO accounted for 27% of residential systems, a slight increase from previous years. This uptick is likely due to higher interest rates on solar loans, making TPO models more attractive to consumers. The report suggests that TPO shares may continue to rise, particularly as TPO systems become eligible for higher tax credits under the Inflation Reduction Act.

For non-residential systems, TPO shares have remained relatively stable. The report notes that TPO is more prevalent in states with high solar renewable energy certificate (SREC) prices or lucrative incentive programs, such as those in Washington D.C., Massachusetts, and New Jersey. However, some states limit TPO models or restrict eligibility for incentive programs to host-owned systems, leading to significant variability in TPO adoption across different markets.

Variability in Installed Prices

The report underscores the wide variability in installed prices across the U.S. market, driven by project characteristics, installer attributes, and local market conditions. For residential systems installed in 2023, the 20th to 80th percentile range for installed prices was $3.2/W to $5.5/W. For small non-residential systems, the range was $2.5/W to $4.3/W, while large non-residential systems saw prices between $1.7/W and $3.1/W.

Economies of scale play a significant role in this variability, particularly for larger systems. The report highlights that among residential systems, the largest installations are priced at approximately $1.0/W lower than the smallest systems, reflecting the cost efficiencies gained through larger installations. For non-residential systems, the price difference is even more pronounced, with systems larger than 1,000 kW priced $2.2/W lower than those 10 kW or smaller.

State-Level and Installer-Level Price Differences

The report also explores state-level differences in installed prices, noting that California, despite being the largest market, has residential prices near the national median. However, substantial price differences exist across states, reflecting variations in market size, policy environments, and local economic conditions. For example, states with smaller solar markets or specific policy drivers often exhibit higher prices due to less competition or unique market conditions.

At the installer level, the report finds significant variability in pricing practices. Among the top 100 residential installers in 2023, median prices ranged from $2.6/W to $5.9/W. This variability is attributed to differences in business models, vendor relationships, and local market conditions. The report suggests that while some installers offer lower prices due to efficiencies of scale or lower overhead, others may charge higher prices due to brand positioning or premium service offerings.

The report’s findings have important implications for the future of the U.S. solar market. The continued decline in residential PV prices, coupled with the rise in paired PV+storage systems, indicates a maturing market that is increasingly focused on energy independence and resilience.

However, the recent increase in non-residential prices and the wide variability in installed prices across states and installers suggest that challenges remain, particularly in managing costs and ensuring equitable access to solar energy.

Lawrence Berkeley National Laboratory found that new residential solar installations in the U.S. had a median size of 7.2 kW in 2022, a significant jump from the 2.4 kW seen in 2000, thanks to cost reductions and improved module efficiencies.

The energy storage market in the U.S., including grid-scale, residential and community, commercial, and industrial segments, experienced an 80% year-over-year growth in the second quarter of 2023, adding a total of 5,597 MWh, a report by Wood Mackenzie and American Clean Power Association said.