A new study led by the University of Michigan suggests that climate change will cause the future value of residential rooftop solar panels in the United States to increase by as much as 19% by the end of the century.
The study measures the value of solar, or VOS, as the financial benefits for households including savings on electricity bills and income from selling extra electricity to the grid. This is then subtracted by the initial installation costs..
The authors of the study, to be published in the journal Nature Climate Change on April 19, predict that many U.S. households could see an increase in earnings from residential rooftop solar of up to hundreds of dollars per year by the end of the century. According to study senior author Michael Craig, a rooftop solar installation built today with an average 25-year lifespan will likely experience 2050 weather conditions. This makes it crucial for households to consider the potential long-term financial benefits of investing in solar energy.
The study suggests that it would be beneficial for households to consider the future value of solar when installing it. By doing so, the study indicates that they could potentially see even more benefits from solar and may be inclined to install more of it. This increased awareness of the long-term value of rooftop solar could lead to more widespread adoption of the technology, ultimately helping to reduce carbon emissions from power generation in the US and worldwide. The study also found that the expected financial gains from rooftop solar are primarily driven by the growing demand for residential air conditioning as the climate continues to warm. Another important factor that impacts the value of rooftop solar is the increasing demand for residential photovoltaic systems.The researchers have stated that the future performance of solar panels will be affected by climate change. Craig and his team conducted a study using data from 2,000 households in 17 U.S. cities to analyze air-conditioning demand and solar-panel performance under future climates using a moderate climate-warming scenario called RCP-4.5. The study found that the value of rooftop solar panels increased in almost all cities, both warm and cold. Miami experienced the largest increase in value, while Minneapolis was the only city to see a decrease in the financial benefits of rooftop solar for households. This is the first study to quantify the impact of future climates on solar-panel performance.The research lead author, Mai Shi, stated that the worth of rooftop solar in the face of climate change is significant. They found that households in the U.S. will experience more cost savings from rooftop solar in the future compared to the past due to changing weather patterns. As the demand for home-cooling increases, a larger portion of solar-generated electricity will be used to cool homes instead of being sold to the electrical grid. This will benefit owners of rooftop solar systems. In several states, using solar energy to power a home will lower the homeowner’s electricity bill.
Households are billed at the full retail cost for the electricity they use, but if they send electricity back to the grid, they are credited at a lower rate.
According to Craig, as the demand for cooling increases, more solar power is used within the household instead of being sent back to the grid. It is generally more beneficial for a rooftop solar panel owner to consume the power generated by their panels rather than exporting it to the grid.
Based on the moderate RCP-4.5 climate scenario, the study shows that residential space cooling demand is expected to rise in all 17 cities. The demand is projected to increase by an average of 35% by mid-century and by an average of 64% by the end of the century.The researchers suggest that there will be an increase in the installation of residential rooftop photovoltaics in cities across the U.S. in the future. They also point out that the performance of solar panels is affected by rising air temperatures and changes in cloud cover. Solar panels generate less electricity as the air temperature or cloud cover increases. Therefore, the future performance of solar panels will differ across the U.S. depending on the weather conditions in each city, such as Ann Arbor, Austin, Chicago, and Dallas., Detroit, Houston, Louisville, and Milwaukee may experience decreased solar panel efficiency due to rising air temperatures. However, the reduced cloud cover could potentially lead to an increase in the amount of sunlight reaching the panels. Researchers suggest that these two factors “are opposing but roughly comparable,” ultimately canceling each other out.
On the other hand, cities like Baltimore, Boston, Los Angeles, Minneapolis, New York City, and Phoenix are projected to become both warmer and cloudier as a result of climate change. This is expected to “significantly decrease” the electrical output of rooftop solar systems in these areas.
Overall, the increased cooling demand in all 17 cities is likely to outweigh the changes in solar panel efficiency.The study found that rooftop solar panels have led to financial gains for most owners due to increased electrical output, except for in Minneapolis where cooling demand is expected to decrease. The future financial benefits of rooftop solar will be primarily experienced by households that can afford to install panels, but there are programs in place to make it more accessible to lower-income individuals as well. These programs help offset the costs of solar, making it available to a wider range of people.Governments also have the option to set up rooftop solar systems on public buildings, such as subsidized housing, to handle the initial costs and provide solar benefits to residents. Community solar programs can also have a positive impact on entire communities, including households that may not have the resources or capability to access rooftop solar on their own.
Along with Craig and Shi, the Nature Climate Change paper was co-authored by Xi Lu from Tsinghua University.
The research received support from the National Key R&D Program of China, U.S. National Science Foundation, National Natural Science Foundation of China, and Carbon Neutrality and Energy System Transformation Project.</p rnrn
Journal Reference:
- Mai Shi, Xi Lu, Michael T. Craig. Climate change will impact the value and optimal adoption of residential rooftop solar. Nature Climate Change, 2024; DOI: 10.1038/s41558-024-01978-4