There are several low-carbon technologies available for generating electricity. But are these alternatives better than fossil fuels and nuclear power? To address this question, we need to evaluate not only the emissions from different energy sources but also the health benefits and ecological impacts of green energy. Electricity production accounts for roughly a quarter of global greenhouse gas emissions, and as more populations gain access to electricity and the use of electronics and electric vehicles increases, this demand is expected to grow. Thus, combating global warming will require a transformation in how electricity is produced.
However, in this transition, it is crucial to avoid environmental pitfalls like ecosystem disruption, wildlife threats, or air pollution. In a research study, we explored the impacts of electricity generation from renewable sources, nuclear, and fossil fuels, with and without the technology to capture and store CO₂ underground. Our analysis considered the environmental effects related to building, operating, and dismantling power plants, as well as the production, transportation, and burning of fuels. We compared a baseline scenario with a low-carbon electricity scenario designed to keep global temperatures from rising more than two degrees Celsius above preindustrial levels by 2050, a threshold climate scientists say could prevent dangerous climate change.
Our findings strongly indicate that fossil fuels, especially coal, significantly harm the environment, whereas most renewable power projects have lesser pollution-related impacts on ecosystems and human health. Despite this, no energy source is entirely free from negative environmental effects. The location of power plants, the design of projects, and the choice of technology are critical factors that investors and governments must carefully evaluate. Switching from fossil fuels to renewable energy sources like solar, wind, hydropower, and geothermal power can reduce various pollution types. The pollution difference between fossil fuels and some renewable options is striking. For instance, the entire process of creating, installing, and using photovoltaic panels produces less pollution than just the fuel delivery to a coal power plant, including mining.
Concerning the environmental impact of producing renewable energy systems, photovoltaics (PV) perform very well in our analysis. The energy required to produce PV cells today is significantly lower than it was before. The carbon emissions for each unit of PV electricity are a tenth or less compared to even the most efficient natural gas plants. Health issues like respiratory diseases from particulate matter are about one-tenth of those from modern coal plants equipped with advanced pollution control. We observed similar results for water and soil pollution effects on ecosystems. However, solar panels need much more space to generate the same power as fossil or nuclear plants. Does the large area required for solar panels pose a problem? Not necessarily. The land needed to generate a kilowatt-hour from PV is similar to that of coal power when accounting for mining-related land. Moreover, around half of the PV installations in our 2050 scenario could be set on rooftops.
Making PV panels does demand various metals, many sourced from limited locations, some of which are highly toxic. Waste treatment and recycling, which we didn’t include in our study, are important considerations. PV only generates power when the sun shines, but another solar technology, concentrating solar-thermal power (CSP), which focuses light to produce heat, may be a promising path forward. It has similar pollution reduction performance and offers the possibility to store heat, thus providing power in the evening. We projected that CSP, which is currently much less common than PV, would account for a quarter of solar electricity in our low-emissions scenario.
Hydropower’s environmental impacts vary widely. Some dams have significant climate effects due to methane emissions from decomposing biomass in reservoirs, while others cause severe ecological harm through habitat destruction, blocking aquatic species migrations, and impeding sediment and nutrient flow affecting floodplains and deltas. Conversely, reservoirs can create new habitats for birds and other species. Site selection and project design are crucial in hydropower. Some projects may be economically feasible but should be avoided if they result in substantial environmental degradation. For others, impacts can be reduced by strategies like ensuring environmental streamflows and installing fish ladders to assist migrating species.
Similar principles apply to wind power. Minimizing habitat destruction during construction and adapting operations can lower collisions with birds and bats. Wind resources also vary greatly by location, suggesting a need for choosing areas with ample wind resources. Biomass energy, which involves burning plant materials for power, is essential in most plans to keep global warming below two degrees Celsius above preindustrial levels. Unlike PV and wind, biomass offers on-demand renewable energy.
When combined with CO₂ capture and storage, biomass energy can remove carbon from the atmosphere and bury it. Burning quick-growing plants such as willow and miscanthus for energy can also lower biopower’s greenhouse gas emissions. This can reduce the health effects associated with burning biomass. However, the land required for these fast-growing plants is far greater than for other power sources, with significant ecological impacts. Our study found that biomass’s ecological damage per kilowatt-hour, as measured by species lost, is similar to coal and gas. Hence, while biomass energy reduces greenhouse gases, it is more beneficial for ecosystems only when used with carbon capture and storage.
Efforts to mitigate climate change represent a unique chance to not only cut carbon emissions but also tackle various environmental problems. Nonetheless, to maximize these technologies’ environmental benefits without causing unforeseen harm, low-carbon technologies should be implemented without encroaching on sensitive habitats. While many understand that solar and wind are low-carbon energy options, bioenergy and carbon capture and storage are crucial in nearly all scenarios for rapidly cutting carbon emissions. Our results highlight the need for finding ways to use these technologies while minimizing their negative impacts on ecosystems. It’s not only about using clean energy but also about carefully considering the technology choices, their locations, and implementation methods.