Coal-fired power plants are the single largest source of electricity in the Philippines, but their impact extends beyond the grid. A growing body of research shows that the pollution from these plants is actively reducing the country’s solar power output, creating a paradox where the fuel used to keep the lights on is simultaneously dimming the potential of a cleaner energy source. In 2023, for example, over a quarter of potential global solar production was lost to atmospheric conditions, with aerosols — tiny particles largely from coal burning — accounting for a significant slice of that loss. For the Philippines, a nation with immense solar potential, this means that every new coal plant may be undercutting the performance of every solar panel it was meant to complement.
This isn’t just a global abstraction. The Philippines has become Southeast Asia’s most coal-reliant nation, with coal’s share of the power supply climbing from 27% in 2006 to 63% in 2023. That shift has made electricity generation the country’s largest contributor to carbon dioxide emissions, overtaking even the diesel-powered transportation sector. Understanding how coal pollution directly sabotages solar energy — and what that means for the country’s energy transition — is essential for anyone following the debate over the Philippines’ energy future.
How Coal Pollution Dims Solar Power
The mechanism is straightforward but often overlooked. Coal combustion releases sulfur dioxide, which forms sulfate aerosols in the atmosphere. These tiny particles, along with nitrous oxides and carbon-rich material from fossil fuels, scatter and absorb incoming sunlight. For solar panels, which depend on direct and diffuse light, this means less energy reaches the photovoltaic cells. The researchers behind the 2026 Nature Sustainability study estimated that sulfur dioxide aerosols account for nearly half of all aerosol-related solar losses globally, with carbon-rich material from fossil fuels adding another 18%.
The scale of the effect is substantial. In 2023, global solar power lost about 6% of its potential output to aerosols — equivalent to over 500 terawatt-hours, or the full annual output of 84 coal plants each with a 1 GW capacity. For context, the Philippines’ entire coal fleet has a combined capacity of about 9.88 GW. The study also found that in China, where coal plants and solar farms are often geographically aligned, aerosols reduced solar production by 7.7% overall and offset anywhere from a third to half of annual solar growth. The researchers noted that “the spatial distribution of photovoltaic losses in China mirrors that of its coal-fired power capacity,” and that 30% of those losses could be attributed directly to coal burning. This geographic overlap is a pattern the Philippines, with its growing solar ambitions and entrenched coal infrastructure, should watch closely.
The Philippines’ Coal Dependency and Its Human Cost
The Philippines now operates 28 coal-fired plants with a combined capacity of 9.88 gigawatts, and coal’s share of electricity generation rose to 61.9% in 2023, up from 59.1% the previous year. This increase pushed the country ahead of major coal users like China, Poland, and even Indonesia, making it the most coal-dependent nation in Southeast Asia. Meanwhile, renewables contribute just 22% of the power mix, and the country’s wind and solar potential, as noted by energy think tank Ember, “remains almost entirely untapped.”
The human toll is not theoretical. A 2020 study by the Centre for Research on Energy and Clean Air (CREA) found that existing coal plants were responsible for 630 air-pollution deaths in the Philippines in 2019, with 68% of those occurring in Luzon. The study projected that Bataan, where several new coal projects are planned, could see a 103% increase in premature deaths if those plants are built. In the small Mindanao town of Villanueva, residents have voiced similar concerns. Ma. Teresa “Baby Yap” Calion, who moved to the area four years ago, told PCIJ that she blames the nearby coal plants for her asthmatic father’s worsening condition and repeated hospital trips. SPI Power Inc., which operates one of the plants, told PCIJ it “has not received official complaints nor have any health-related concerns been escalated” to the company.
The economic cost is also mounting. Energy Secretary Raphael Lotilla has said the government needs up to USD 500 billion in investments to retrofit or phase out fossil fuel plants. Meanwhile, nine coal-fired power projects totaling 2,255 MW — approved before the 2020 moratorium — are expected to come online by 2028, with five of those in Bataan. These new plants will lock in coal dependency for decades, even as the country’s own targets call for 35% renewable energy by 2030 and 50% by 2040.
What Gets Missed in the Solar vs. Coal Debate
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| Region | Solar Loss from Aerosols | Coal Attribution | Key Factor |
|---|---|---|---|
| China | 7.7% | 30% of losses from coal | Solar farms and coal plants overlap geographically |
| United States | ~3% | Lower | Solar in south/west; coal in east/northeast |
| Global Average | ~6% | ~50% from sulfur dioxide | Coal is the dominant source of sulfate aerosols |
The most significant nuance in this debate is the geographic alignment of coal plants and solar farms. In China, where the two are often built in the same regions, the penalty is severe. In the United States, where solar is concentrated in the south and west while coal plants are in the east and northeast, the annual losses were less than half of China’s — about 3%. For the Philippines, this matters because the country’s solar potential is strongest in areas that may also host coal infrastructure. If new solar farms are built near existing coal plants — or near the nine new coal projects expected by 2028 — their output could be systematically reduced by the very pollution those plants produce.
The Timing Problem
Another overlooked factor is timing. Aerosol concentrations are not uniform throughout the year. In many regions, pollution peaks during dry months when solar irradiance is also highest. This means the worst solar losses occur precisely when panels would otherwise be most productive. For a country like the Philippines, which experiences distinct wet and dry seasons, this seasonal penalty could significantly affect the economics of solar investments. A solar farm that looks viable based on annual averages may underperform during the dry season when demand for air conditioning — and therefore electricity — is at its peak.
The Growth Offset
Perhaps the most frustrating finding from the research is that new solar capacity is being partially negated by existing coal pollution. Globally, between 2018 and 2023, the world installed enough solar capacity to produce an average of 250 TWh of additional power per year. But aerosols were eating 75 TWh of that — nearly a third. In the Philippines, where solar and wind generation increased to 3.7 TWh in 2023 from less than 1 TWh in 2015, the same dynamic is likely at play. Every new solar panel installed in a polluted area delivers less than its rated capacity, and the gap is filled by — you guessed it — more coal.
What Can Be Done About the Coal-Solar Conflict
The path forward involves three distinct but interconnected actions: retiring coal plants early, strategically siting new solar farms, and addressing the pollution that already exists. Each comes with its own tradeoffs and timelines.
Early Retirement of Coal Plants
The most direct solution is to retire coal plants before the end of their operational lives. An analysis by TransitionZero found that early retirement of Philippine coal plants by just five years could prevent around 290 million tonnes of carbon dioxide emissions — almost double the country’s annual emissions. Without early retirement, the current coal fleet is projected to operate until between 2047 and 2051. The STEAG plant in Villanueva, Mindanao, is a test case: a 210 MW facility scheduled for transfer to the Power Sector Assets and Liabilities Management Corp. (PSALM) in 2031 under a Build-Operate-Transfer agreement. Under an early proposal from the Asian Development Bank’s Energy Transition Mechanism (ETM), the plant was supposed to be retired five years early — which would be next year. That timeline has not been confirmed, but it illustrates the kind of accelerated retirement needed across the fleet.
Strategic Solar Siting
Not all locations in the Philippines suffer equally from aerosol pollution. Solar farms should be sited where coal pollution is lowest — ideally upwind of major coal plants or in regions with cleaner air. This requires detailed mapping of aerosol concentrations and wind patterns, data that the Department of Energy and the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) could develop. The payoff is significant: a solar farm in a low-aerosol area could produce 6% to 8% more electricity than an identical farm near a coal plant, without any additional investment in panels or technology.
Addressing Existing Pollution
Even without retiring coal plants, reducing their emissions can improve solar output. Installing flue-gas desulfurization systems to capture sulfur dioxide, for example, would reduce the formation of sulfate aerosols. This is not a hypothetical fix — it is standard technology in many countries. The cost is significant, but it would simultaneously improve public health and boost solar performance. The CREA study’s estimate of 630 annual deaths from coal pollution provides a powerful cost-benefit argument for such investments.
Frequently Asked Questions
Does this mean solar panels are useless near coal plants? ▾
Can’t we just clean the solar panels more often? ▾
Is the Philippines’ solar potential still worth pursuing? ▾
How does the Philippines compare to other countries on coal reliance? ▾
What is the Energy Transition Mechanism (ETM)? ▾
Moving Beyond the Coal Trap
The evidence is clear: coal pollution does not just harm lungs and warm the planet — it directly reduces the output of the solar panels that are supposed to replace it. For the Philippines, which has become Southeast Asia’s most coal-dependent nation while sitting on enormous solar potential, this is not a minor technical footnote. It is a structural problem that demands a coordinated response. Retiring coal plants early, siting solar farms strategically, and cleaning up existing emissions are not separate goals — they are parts of the same solution. If this was useful, you might also want to read how communities are fighting pollution on the front lines.
Sources
Metro Manila’s air quality crisis — A closer look at how urban air pollution affects health and daily life in the capital.
Tech solutions for pollution in the Philippines — An overview of technologies being deployed to monitor and reduce pollution across the country.
Solar power production undercut by coal pollution. Ars Technica, 2026.
Small Philippines town, coal plant key to dirty energy exit. Philippine Center for Investigative Journalism, 2025.
Philippines struggles to end coal despite renewables pledge. Dialogue Earth, 2024.
