Air Quality and Energy Interactions in South and Central Asia

NREL's investigations into South and Central Asian air quality reveal some interesting and challenging linkages between air pollution and power generation in the region.

The U.S. Department of State commissioned NREL to examine connections between electricity production and air quality in South and Central Asia. There were two aspects to this work: one was focused on identifying electricity-sector policies that can modulate the impact of fossil-fuel power generation on air quality and health; the other was focused on the impact of air pollution on solar power generation.

Policy Investigations

The electricity sector is a substantial source of air pollution and associated health problems in Asia and elsewhere. Fossil-fueled power plants emit a wide variety of harmful pollutants. Once released into the atmosphere, there is no practical way to remove air pollutants, which means that policies designed to improve air quality have to limit the pollutants before release. However, tackling such pollution is challenging because developing economies also need to provide electricity as a basic necessity for their citizens and as an engine of economic growth.

NREL studied the interactions between development and management of the electric sector and air quality in the South and Central regions within Asia, which provide examples of:

1. Policies that directly regulate air quality by limiting emissions from specific point sources (by restricting operating hours, for instance)
2. Indirect policies that incentivize or disincentivize polluting activities, such as policies to encourage fuel switching, for example.

Interactions of Air Pollution and Solar Power Output

Solar output in polluted areas can be reduced as a result of particulate matter (PM) air pollution. This is because particles in the air can block the sun's rays before they reach the ground or roofs where solar panels are placed. Studies indicate that areas with high ambient PM concentrations could experience a decrease of up to 25% in photovoltaic power output compared to pollution-free conditions. Yet project financial pro formas and solar resource assessments typically do not fully consider the impact of PM pollution on solar performance because prior-generation satellite imagery is too coarse to provide data at the required resolutions.

Taking advantage of advances in imagery from the latest generation of satellites, NREL developed spatially and temporally resolved data on the solar radiation attenuation properties of PM (called aerosol optical depth, or AOD) derived from current satellite coverage, which can be incorporated into a solar resource database for improved performance assessment of solar power projects. These methods, first developed for South Asia, are applicable to any global region.

Publications

An Overview of Policies Influencing Air Pollution from the Electricity Sector in South Asia, NREL Technical Report (2021)