Earth Day has promoted environmental awareness on April 22 every year since 1970. The theme of this year’s celebration is “Our Power, Our Planet,” a call to action to triple the amount of renewable energy and clean electricity available worldwide by 2030.

California is a national leader in renewable energy, and the state has set ambitious goals, including 60% renewable energy by 2030 and 100% by 2045. Renewable sources such as wind, solar and hydroelectric power are increasingly being integrated into the state’s energy generation.

The World Economic Forum estimates the transition to clean energy will generate 10.3 million new jobs worldwide by 2030, offsetting the 2.7 million jobs that are anticipated to be lost in the fossil fuel industry.

USC News asked several of the university’s leading experts about the future of energy sources that help reduce our dependence on fossil fuels and lower greenhouse gas emissions.

How can renewable energy systems be made more efficient?

“The efficiency of renewable energy sources, such as wind and solar power, is gradually improving due to advancements in technology,” said Shon Hiatt, associate professor of management and organization at the USC Marshall School of Business and director of the Business of Energy Transition initiative.

“Notably, the efficiency of wind turbines has increased with the development of larger turbines, primarily used for offshore applications (35%-40%). Similarly, solar panel efficiency has reached a maximum of approximately 29% for high-end models. However, the ability of renewable energy sources to meet global demand is limited. Non-baseload power sources, such as wind and solar, face challenges in providing consistent energy supply due to their dependence on unpredictable weather conditions. As intermittent energy sources increase their presence in the grid, energy costs rise due to the difficulties in meeting demand requirements, putting a burden on consumers and businesses.

“In contrast, geothermal energy offers a promising alternative as a baseload renewable energy source. The cost of developing geothermal energy is decreasing, driven by the adoption of horizontal drilling technologies borrowed from hydraulic fracturing. This has resulted in a reduction of one-third in drilling costs. Additionally, regulatory costs for geothermal energy are substantially lower than those for nuclear energy, and the United States possesses considerable untapped geothermal potential.

“Looking ahead to the next five to 10 years, it is likely that the primary sources of electricity to support the growing demand from AI data centers in the United States will be combined-cycle natural gas and geothermal energy with nuclear power expected to emerge as a viable option in the 2030s.”

How can we scale up renewable energy to meet global demands?

“Over the past decade, the levelized cost of renewable electricity sources like wind and solar has plummeted. In many regions, these technologies are now more cost-effective than generating electricity with traditional fossil fuels,” said Kelly Sanders, associate professor of civil and environmental engineering at the USC Viterbi School of Engineering.

“Additionally, the cost of utility-scale batteries has plummeted sharply, helping to address concerns about solar and wind intermittency when coupled with storage technologies. Looking ahead, we anticipate further enhancements that will lower the costs of components and boost both the efficiency and longevity of these systems, making wind and solar even more economical. However, to expedite the transition to renewable energy, targeted policies and regulations that streamline the development of the transmission and distribution infrastructure necessary for connecting renewable resources to load centers are crucial.”

What policies and regulations are necessary to accelerate the renewable energy transition?

“The current energy and environmental policies and regulations, which include incentive programs and mandated goals, have achieved a great deal of renewable energy development in the U.S. in the last 20 years,” said Mohammed Beshir, professor of electrical engineering-systems practice at USC Viterbi. “Chief among these incentives and policies include: the investment tax credit (ITC) and the production tax credit (PTC) that are provided by the U.S. federal program, and the renewable portfolio standard (RPS) and the net-metering (NM) programs run by the states. These are often coupled with local governments’ and utility companies’ rebate and other incentive programs.

“Collectively, these policies and programs have allowed great deployment of solar and wind power resources in the U.S. the last several years, reaching over 180 gigawatts of solar and 150 gigawatts of wind in 2024. This is translating to a level of electric power demand being met by renewable energy. This trend is expected to continue in the future to the extent that we have the above-mentioned policies and programs continue in the future. Any new energy policy that undermines the above-mentioned programs will greatly hamper the future growth of renewable systems.”

What role will nuclear energy play in the future?

“Nuclear energy stands poised to serve as a cornerstone of the global transition to a low-carbon future,” said Najmedin Meshkati, professor of civil and environmental engineering, industrial systems engineering and international relations at USC Viterbi.

“Unlike intermittent renewable sources such as wind and solar, nuclear power provides reliable, large-scale baseload electricity that can stabilize energy grids and complement clean energy portfolios. Recent policy and industry developments underscore this renewed momentum. By 2050, nuclear energy capacity is expected to triple globally to meet net-zero emissions targets, as pledged by 22 countries at COP28 in Dubai in December 2023.”

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Who will benefit from renewable energy?

“The shift to renewable energy isn’t just about advancing technology; it’s about transforming who benefits from it,” said Manuel Pastor, director of the USC Equity Research Institute at the USC Dornsife College of Letters, Arts and Sciences. “My book, Charging Forward, about California’s Lithium Valley highlights this issue: Can we extract lithium for electric vehicles in a way that protects the environment, empowers local residents and creates good jobs?

“We need to move away from a reliance on fossil fuels, but the transition to a clean energy economy must be green and just, so that the shift to EVs results in shared prosperity for all.”

What is the environmental impact of renewable energy technologies?

“Renewable energy, such as wind and solar, are what are called defused energy sources, because of the energy densities of the sources,” Beshir said. “That means, it requires a large amount of land to collect the amount of energy required to generate electricity as compared to fossil power generation. Thus, land-use and associated environmental issues are key considerations. Displacement of agricultural land for renewable energy production is an utmost issue in many regions of the world. Furthermore, the biological and animal and plant natural habitat impacts are key issues. Other impacts such as visual, noise and avian are most critical for wind energy plants. Other renewable resources such as biomass and ocean-based generation also have major environmental concerns, regarding visual [impact] and impact to the animal and plant habitat.”