As the shadow of climate change looms ever larger, with greenhouse gasses driving rising temperatures and wreaking havoc on our planet, the calls for renewable energy to replace fossil fuels have intensified.
Among the energy alternatives being debated, solar energy has become one of the most widely touted primarily because the raw material that powers solar is essentially ‘free’: sunshine. But is this true? Can the world run on sunshine?
What’s The Evidence ?
A new study in Nature Communications, one of the leading peer-reviewed scientific journals in the world, reveals how solar energy is poised to reshape the global energy landscape, heralding a new era of dominance in renewable electricity generation within the next two decades.
The research, led by University of Exeter scientists, shows a rapid increase in productivity and technological advancement that positions solar to substantially displace coal, oil and gas, the nonrenewable energy sources responsible for the majority of greenhouse gas emissions which are accelerating climate change. Greenhouse gasses, such as carbon dioxide and methane, trap heat in the Earth’s atmosphere, causing the planet to warm and leading to devastating consequences like rising sea levels, more extreme weather events, and ecosystem disruption.
The study projects that solar energy will account for over half of global electricity generation by the year 2050, while the cost of solar is expected to decline by 60% over that same period.
“A single year of sunshine exceeds all known existing energy reserves of oil, coal, natural gas and uranium put together. The future is renewable.”
How does sunshine become energy?
Solar energy is converted into electricity using photovoltaic (PV) cells made from semiconductor materials like silicon. When sunlight hits these cells, it excites electrons in the semiconductor, creating free electrons and “holes” (areas where electrons are missing). This movement of electrons and the corresponding holes generate a flow of electricity in the form of direct current (DC).
These PV cells are grouped into modules, also known as panels, which can be assembled into larger modules called arrays.. The electricity generated in DC form is then converted to alternating current (AC) using an inverter, making it suitable for everyday use in homes and businesses.
One of the significant advantages of solar PV systems is their silent operation, and low maintenance, attributed to their lack of moving parts. Additionally, solar panels are designed to adapt to various environmental conditions, maintaining efficiency under different weather scenarios.
Beyond these operational benefits, it’s important to consider solar capacity — the measure of how much electricity a solar system can generate. Arrays can be scaled to fit different needs, from small residential systems on rooftops to extensive commercial solar farms. Each module functions as a small electricity generator, and when combined, they can produce a significant amount of power, solar capacity refers to the maximum electrical output a solar power installation can produce under ideal conditions.
What Determines Solar Capacity?
Solar capacity is determined by several factors, including the size of the solar array, the efficiency of the photovoltaic cells, and the amount of sunlight the system receives. Understanding solar capacity helps to evaluate how effectively a solar PV system can meet energy needs and contribute to overall energy goals.
Solar energy generation, which is the actual amount of energy created, not surprisingly followed a significant upward trajectory too. In 2023, the US generated 238,121 gigawatt-hours (a gigawatt is equal to 1 billion watts) of electricity from solar which represents an eight fold increase from the amount of electricity generated from solar just ten years earlier in 2014.
Total U.S. solar capacity is projected to grow to 673 gigawatts (GW) by 2034. With this capacity, and knowing that the average U.S. household in 2022 consumed the equivalent of 0.0108 gigawatt-hours (GWh) annually, it is estimated that solar energy could potentially power over 100 million homes in America in just ten years.
“If we put solar panels on half the world’s roof tops we could power the planet. Is it going to be easy? Nothing good is ever easy but that should not stop us. This is the world’s Moon Shot , yet we can and we will achieve this.”
Who Is Leading the Solar Race In The US?
In the US, California generates 68,816 gigawatt-hours and Texas generates 31,739 gigawatt-hours from solar. With the amount of solar-based electricity generated in one year, it is estimated that California could power San Francisco for 13 years, and Texas could power Austin for 2 and a half years. However, the development of solar power in these two states are facing vastly different political climates.
California has enthusiastically embraced solar energy to become the nation’s leader in solar production, perhaps due to its deeply rooted environmental policies and historical crises. Both of which have highlighted the need for renewable energy sources. The state’s journey toward solar supremacy began during the energy crises of the 1970s, which exposed the vulnerabilities of relying on fossil fuels. The state’s sunny climate, combined with its technological and economic capacity to support large-scale solar projects, further catalyzed the solar energy boom.
Leading with its ambitious Senate Bill 100 (SB 100) released in 2018, which mandated a transition to 100% zero-carbon and renewable energy by 2045, the Golden state has embraced comprehensive and structural changes to its energy system, emphasizing decarbonization through extensive investments in utility-scale solar and wind projects, alongside enhancing grid reliability and capacity. The framework is clearly designed to address environmental justice and equity, with an acute focus on solar energy.
In stark contrast, Texas appears to be retreating from its earlier welcoming stance towards renewables. Despite being the national leader in wind generation and second in solar power generation, 2023 legislative sessions have been fighting against the growth in renewable energy production. Attempting to introduce proposals that would increase the regulatory and financial burden on renewable energy projects.
These proposals, perceived by some critics as favoring the fossil fuel sector, include requiring additional state approvals for new renewable projects and imposing financial barriers that could drastically increase the cost of connecting renewable energy sources to the state grid. This legislative pushback reflects a broader political debate over the role of renewable energy in Texas’s future, suggesting a significant divergence from California’s proactive renewable energy policies.
According to the 13th National Solar Jobs Census released in 2022, there are 263,883 solar energy workers across the country, working to manufacture, install, distribute, and carry out maintenance, marking a 3.5% growth in solar jobs compared to 2021.
“One recent estimate found that renewables lowered the cost of electricity to Texans by $11 billion last year, or $423 for every customer served by the state’s predominant power grid. Over the past five years, Texas has added 2,800 jobs to support wind and solar power generation at the same time that the state has lost 44,000 oil and gas extraction jobs, in part because automation has allowed producers to drill more wells while employing fewer roughnecks.”
Globally How Is Solar Doing?
In other parts of the world, solar energy is also on the rise, experiencing a rise in capacity and popularity. China has set an ambitious target of reaching 1,200 gigawatts of renewable capacity by 2030—a goal it is poised to achieve by 2025, five years ahead of schedule. This rapid expansion is exemplified by China’s solar capacity, which is expected to reach nearly 1,000 gigawatts by the end of 2026.
This effort was boosted with the help of the national government through different legislations and programs providing subsidies for the PV sector since the early 2000s. While still using 63% of its energy from fossil fuels, solar energy has become 4% of the electricity grid. In 2022 alone, China installed as much solar capacity as the rest of the world combined and continued to double down on its solar initiatives in 2023.
Meanwhile, Europe is also making significant strides in the solar energy sector, driven by a sharp decrease in costs and an increasing awareness of the environmental benefits. Under the European Green Deal and the REPowerEU plan, the EU aims to dramatically increase its solar capacity, with a goal to reach nearly 600 gigawatts by 2030.
This increase represents a strategic move to reduce reliance on imported fossil fuels and enhance energy security. The EU has rolled out various initiatives such as the European Solar Rooftops Initiative and the EU Solar PV Industry Alliance to meet these ambitious targets. Additionally, solar energy jobs in the EU have surged, highlighting the sector’s role in boosting the economy and contributing to the job market.
Australia too is embracing solar power, with solar PV generating around 10% of the nation’s electricity by the end of 2021. Over 30% of Australian households have installed rooftop solar systems, and the capacity is growing. The Australian government has invested significantly in solar research and development, supporting projects that aim to increase solar module efficiency and reduce balance of system costs.
According to the Solar Energy Industries Association (SEIA), an industry trade association, the solar industry is poised for significant growth over the next decade, with projections showing that by 2030, one in eight American homes will use solar energy for electricity production, on track to quadruple its growth in 2020.
The Inflation Reduction Act
The Inflation Reduction Act of 2022, explicitly supports the development and manufacturing of renewable energy and made historic investments in clean energy. The Act earmarks $369 billion for climate and energy initiatives, a lot of which will go towards tax credits, both for the solar industry and for the individual homeowners, who want to install solar panels.
The Department of Energy’s Loan Programs Office (LPO), has an unprecedented $400 billion to lend towards clean energy innovation. The LPO, led by the winner of the 2024 Earth Day Climate Leadership Gala award winner Jigar Shah, provides vital financing to innovative renewable projects, including solar, and is expected to encourage more private sector investment. For homeowners, the federal solar tax credit allows homeowners to deduct 30% of their system’s cost from their federal tax bill.
Will Consumers Save Money Going Solar?
Installing solar panels also has become a major cost-saving measure in dealing with increasing utility bills. After the initial investment in equipment and installation, it typically takes 5 – 15 years for solar panels to generate effectively ‘free’ electricity. With the average household consuming 10.8 megawatts-hours of electricity annually and the national average electricity rate at $0.17 per kWh as of March 2024, families spend around $1,834 per year on electricity.
Considering the 2.8% annual increase in electricity prices over the past decade, the average homeowner can expect to save approximately $46,000 over 25 years after installing solar panels.
Although solar panel warranties typically last 25 years, most systems continue to perform well for 30 years or more, leading to even greater long-term savings for homeowners. Websites such as Google’s Project Sunroof will allow homeowners to type in their address, showcase the usable sunlight per year and square footage available to construct solar panels, and calculate the potential savings compared to regular electricity bills in the long run.
All of this too comes with the added bonus that this form of energy contributes no greenhouse gasses and therefore does not contribute to climate change.
“Every time you turn on a light bulb or get in a car, you are making decisions about what kind of world you want to live in.”
That’s The Good News, Here’s The Less Sunny.
Despite its many benefits, solar power is not without its challenges.
One of the primary concerns is the variable nature of sunlight! The amount of sunlight available for conversion into electricity can be affected by the time of day, the weather, the seasons and of course location. The Global Solar Atlas, reveals how sunshine radiation and density vary significantly depending on these factors.
The sun doesn’t shine anywhere 24 hours a day, 12 months of the year, so the intermittent nature of solar energy is always going to be an issue. Which means solar power has to come with efficient and reliable energy storage solutions to ensure that on high sunshine days enough electricity is generated enough to power low sunshine days.
Researchers are working on developing more efficient lithium-ion batteries but lithium mining does have its own set of environmental issues, as well as the dangers it poses to miners. The other solution being developed are faster-charging solid-state batteries which would create better storage solutions. Solid-state batteries aim to replace the liquid electrolyte in traditional batteries with a solid material. This would make these batteries charge more quickly and potentially offer longer life.
Finally ‘net metering’, is another way of managing battery storage issues. It allows homeowners to earn credits for the excess energy that their system makes when it is very sunny and sends it back to the network electricity grid. They can either cash these credits in or use them to buy electricity back from the grid in low sunshine periods, when their solar panels are not creating the electricity they need.
Sunshine to Electricity Conversion Efficiency
The other big issue is ‘conversion efficiency’ which is the percentage of the solar energy shining on a PV device that is converted into usable electricity. In layman’s terms it just means that not all the sunlight that hits solar panel arrays is turned into electricity, in fact most single sided solar panels have efficiencies of just 17-20%.
But solutions are coming. Firstly multi-junction PV cells, these panels are designed to capture more sunlight than traditional panels. Imagine stacking different types of solar panels on top of each other—each layer captures different types of sunlight. This makes these new panels up to 45% more efficient at generating electricity. Right now they are still expensive to make, so they aren’t widely available yet.
Secondly bifacial solar panels, are another innovation. These panels have cells on both the front and back. This allows them to catch sunlight that reflects off the ground or other surfaces, increasing their energy production. When paired with tracking systems that follow the sun’s path, bifacial panels can be 30-40% more efficient than regular, one-sided panels.
“For the first time in history, we can provide virtually unlimited, low-cost power to everyone. The impact on living standards worldwide will be profound. Improving the health outcomes of millions, if not billions, of people across the globe.”
Solar Uses A Lot of Land
Additionally, unlike oil fields or coal mines, solar panels need to cover a lot of space to collect enough energy to power cities.
The world’s most forbidding deserts, the Sahara in Africa, the Kubuqi Desert in China, and Mojave Desert in California, have emerged as prime locations for harvesting solar power. With vast, flat expanses, rich silicon (a key material to the production of solar panels) deposits, and perpetual sunlight, deserts are ideal for solar panel installations. As this trend continues, researchers envision transforming the Sahara into a massive solar farm capable of meeting four times the world’s current energy demand.
Wildlife Can Be Impacted
While the rapid deployment of solar panels is essential for sustainable energy development, it’s not without its ecological challenges. The expansion of solar farms, especially those that are ground-mounted, can lead to significant alterations in land use, potentially threatening local biodiversity.
According to a 2019 report by independent ecological consultancy firm BSG Ecology, these installations can disrupt habitats, change local flora and fauna dynamics, and may even act as ecological traps by attracting and affecting wildlife in ways that are detrimental. Large tracts of land are often cleared to accommodate solar farms, which can lead to a decrease in biodiversity.
In response to these ecological challenges, several innovative strategies are being explored. One promising approach involves integrating native vegetation and creating habitats within solar farms to support local wildlife and flora. This not only helps in preserving biodiversity but also enhances the ecological value of the area.
Additionally, some projects are adopting “agrivoltaic” systems, which combine solar energy production with agriculture, thereby supporting local communities and maintaining land productivity. Agrivoltaic systems have been widely used across the United States. Farmers use the solar panels to protect their crops, create shade and in turn save water, all while lowering their energy bills.
According to a newly published U.S. Department of Agriculture (USDA) report, solar farms occupy only 336,000 acres, or 0.04% of the entirety of all the farmland in the US. In many rural areas, such as Converse County, Wyoming, where the population density is only 3 people per square mile, local agrivoltaic projects such as the Dutchmen Project have become popular for their ability to generate general revenue and local jobs.
It Takes Energy To Make Solar Panels
While solar panels themselves do not emit greenhouse gasses the manufacturing of solar panels does require a significant amount of energy, particularly in the production of polysilicon, which involves heating giant furnaces to high temperatures.
The carbon footprint of this energy consumption varies depending on the electricity sources used by the solar panel manufacturer, for example every unit of electricity produced in China produces twice as much in carbon emissions, compared to the U.S. efforts to power photovoltaic-panel manufacturing with renewable energy sources like wind, solar, and geothermal is the most obvious solution to this.
The International Renewable Energy Agency (IRENA) predicts that there could be up to 78 million tons of solar panel waste by 2050, but this estimate assumes customers will keep their panels for the full 30-year life cycle. But with falling costs, researchers worry that consumers may choose to replace their panels much earlier, potentially leading to more waste. Current recycling infrastructure for solar panels is vastly inadequate and recycling is not financially incentivized, currently only one U.S. manufacturer (First Solar) has an active recycling initiative.
Here’s why – the cost of recycling a single solar panel is $20 – $30 which far exceeds the cost of $1 to send it to a landfill. New technology out of Australia’s School of Engineering at Macquarie University, are actively working on a solution by developing economically viable ways to delaminate solar panels more efficiently at the end of their lifespan as well as harvest the valuable materials that each panel contains, for example silver.
The Plastic Problem
Despite technological advances, the other issue that the manufacturing of solar panels is yet to solve is plastic.
Plastics are a form of petrochemical, which means it is made using fossil fuels, and it is not biodegradable in any meaningful sense, which has made it a serious environmental challenge due to the proliferation of microplastics and other harmful chemicals such as Bisphenol A and phthalates that leach out from plastics.
Currently, there are two different types of technologies used to manufacture solar panels, and both use plastic polymers, albeit in a relatively low proportion: a typical crystalline silicon PV panel includes about 10% polymer, while thin film technologies like cadmium telluride (CdTe) panels use 3-4% polymer, due to their higher glass content.
Currently, the plastic polymers in solar panel manufacturing are used primarily for encapsulating the solar cells inside the panels. This encapsulation provides a protective layer that safeguards the cells from environmental factors such as moisture, dust, and mechanical damage, ensuring the longevity and reliability of the solar panels.
In the name of cost-effectiveness, numerous leading solar panel manufacturers have shifted to incorporate more plastic in their new models which needs to be addressed. There needs to be a concerted effort by the solar industry to wean themselves off plastic and find ‘greener’ alternatives.
Hazardous Chemicals
Solar panels, particularly those using thin-film technology, also can contain hazardous materials like cadmium, selenium, gallium and indium, which pose environmental and health risks if not handled properly. Mining these materials can lead to significant soil, water and air pollution, and exposure to them can cause serious health issues.
Additionally, while silicone, the main component in most solar panels, is not toxic, the process of cutting silicon into wafers produces silica dust. This dust can be harmful if inhaled over long periods, potentially leading to silicosis, a permanent and irreversible lung disease.
Alternatives to silicon are being researched but in the meantime there should be stricter safety protocols protecting workers and better personal protective equipment (PPE), proper ventilation systems, dust extraction methods, and respiratory protection.
Global electricity generation technology expansion by technology (TWh), showing the time it has taken for key technologies to grow from 100TWh to 1,000TWh.
Source: Ember.
The Future Is Still Sunny
While there are challenges associated with solar energy, there are also viable solutions being developed every step of the way. In contrast, the fossil fuel industry lacks any effective methods for generating energy from oil, gas, or coal without producing greenhouse gasses, which are the primary driver of climate change.
As Denis Hayes, the organizer of the first Earth Day in 1970, noted solar energy has been the fastest growing energy source in the world for the last 19 years straight.
In the past three years, the use of large-scale batteries for energy storage has increased by 900 percent and a recent study by Lawrence Berkeley National Lab found that by the end of 2023, solar, wind, and battery projects accounted for 95 percent of all new electricity capacity planned for the national grid.
So solar may not be able to do it all alone, but in conjunction with other renewable energy sources, like wind, it pretty much can.
“Oil, coal and gas are finite. As long as the sun keeps rising, solar energy is infinite. That seems to present an obvious solution to our energy needs, literally staring us all in the face.”