Researchers at Columbia University Law School Addressed this well in their paper: “Rebutting 33 False Claims About Solar, Wind, and Electric Vehicles“. Here’s what they had to say:
There is overwhelming evidence that the lifecycle emissions of solar energy are far lower than those of all fossil fuel sources, including natural gas. On average, it takes only three years after installation for a solar panel to offset emissions from its production and transportation. Modern solar panels have a functional lifecycle of 30–35 years, allowing more than enough time to achieve carbon neutrality and generate new emissions-free energy.
A National Renewable Energy Laboratory (NREL) report released in 2021 examined “approximately 3,000 published life cycle assessment studies on utility-scale electricity generation from wind, solar photovoltaics, concentrating solar power, biopower, geothermal, ocean energy, hydropower, nuclear, natural gas, and coal technologies, as well as lithium-ion battery, pumped storage hydropower, and hydrogen storage technologies.” The report found widespread agreement that all modes of solar power have total lifecycle emissions significantly below those of all fossil fuels.
The report found specifically that the total lifecycle emissions for solar photovoltaic (PV) and concentrating solar power (CSP) panels were 43 and 28 grams of CO2-eq/KWh (carbon dioxide-equivalents per kilowatt-hour), respectively. Coal, by contrast, generated lifecycle emissions of 1,001 grams of CO2-eq/KWh, and natural gas generated lifecycle emissions of 486 grams of CO2-eq/KWh.
To be fair, there are some outlier studies. For example, one study examined a worst-case scenario in which the coal-powered manufacture of inefficiently sized solar PV cells may contribute to greater lifecycle emissions than the cleanest and most efficient fossil fuel plants. However, the conclusion that solar is worse for the climate than fossil fuels is not backed up by NREL’s more extensive survey.
In addition to having smaller greenhouse gas emissions, solar power likewise outperforms fossil fuels in minimizing direct heat emissions. A 2019 Stanford publication notes that, for solar PV and CSP, net heat emissions are in fact negative, because these technologies “reduce sunlight to the surface by converting it to electricity,” ultimately cooling “the ground or a building below the PV panels.” The study found that rooftop and utility-scale solar PV have heat emissions equivalent to negative 2.2 g-CO2e/kWh-electricity, compared to the positive heat emissions associated with natural gas, nuclear, coal, and biomass.
| Technology | Anthropogenic Heat Emissions |
| Solar PV – Rooftop | -2.2 |
| Solar PV – Utility Scale | -2.2 |
| Concentrated Solar | -2.2 |
| Offshore Wind | -1.7 to -0.7 |
| Onshore Wind | -1.7 to -0.7 |
| Geothermal | 0 |
| Hydroelectric | 0 |
| Wave Energy | 0 |
| Tidal Energy | 0 |
| Nuclear | 1.6 |
| Biomass | 3.4 |
| Natural Gas – CCS/U | 0.61 |
| Coal – CCS/U | 1.5 |
Looking at academic scholarship from outside of the United States, a 2022 analysis from India’s Hirwal Education Trust’s College of Computer Science and Information Technology describes the global impact of solar panel heat emissions as “relatively small.”
Resources
Steffen Schlömer et al., 2014: Annex III: Technology-specific Cost and Performance Parameters , CLIMATE CHANGE 2014: MITIGATION OF CLIMATE CHANGE 1329, 1335 (2014), https://www.ipcc.ch/site/assets/uploads/2018/02/ipcc_wg3_ar5_annex-
iii.pdf.
Carbon Footprint of Solar Panel Manufacturing , COOL EFFECT (June 1, 2021), https://www.cooleffect.org/solar-carbon-footprint.
What Is End -of -Life Management for Photovoltaics? , U.S. DEP’T OF ENERGY SOLAR ENERGY TECH. OFFICE, https://www.energy.gov/eere/solar/end-life-management-solar-photovoltaics.
Jaime Fernández Torres & Fontina Petrakopoulou, A Closer Look at the Environmental Impact of Solar and Wind Energy , GLOBAL CHALLENGES, June 22, 2022, https://onlinelibrary.wiley.com/doi/10.1002/gch2.202200016.
Mark Z. Jacobson, Evaluation of Nuclear Power as a Proposed Solution to Global Warming, Air Pollution, and Energy Security, Dec. 22, 2019, https://web.stanford.edu/group/efmh/jacobson/Articles/I/NuclearVsWWS.pdf.
Sudesh Nagu Kadam et. al, Solar Panel Heat Emission and Its Environmental Impact , 2 INT’L J. ADVANCED RSCH. SCI. COMMC’N TECH. 3 (Dec. 2022), 113, 116, https://ijarsct.co.in/Paper13924.pdf.