Generating electricity using fossil fuels emits carbon dioxide (CO2) as well as toxic air pollutants such as sulfur dioxide (SO2), nitrogen oxides (NOx), and fine particulate matter (PM2.5). As a greenhouse gas, CO2 contributes toward climate effects and global warming. SO2 and NOx have many negative respiratory effects, and also contribute to haze and acid rain. US electrical generation was responsible for 68% of SO2 emissions, 12% of NOx emissions, and 3.4% of PM2.5 emissions in 2014.1 How do we prevent the environmental and human health problems caused by these dangerous emissions? One way to combat these emissions, which were responsible for health issues that led to 31,000 deaths in the US in 2010,2 is to reduce our electricity consumption. Another is through the development and installation of renewable energy technology.
Converting Renewable Energy to Climate and Health Benefits
A recent study by Jonathan J. Buonocore and a team of researchers from Harvard and Carnegie Mellon Universities used a simulation tool to analyze the benefits to climate and human health that could be gained by increasing the deployment of renewable energy in the US. How did the research team determine these benefits? By looking at the ability of these renewable technologies to replace current fossil fuel electricity generation.
Because the fossil fuels industry is well-established, the amount of emissions per unit of electricity generated is fairly well known. For example, here is some information on emission amounts from coal electricity generation. Therefore, the team of researchers could determine the amount of emissions avoided by replacing a portion of existing fossil fuel plants with renewable electricity generation. These emissions are central to climate (CO2) and health (SO2, NOx, and PM2.5) impacts, so by determining the emissions that would be offset by renewable energy, the team could calculate the resulting climate and health benefits. The researchers then used previously calculated values relating emissions to benefits to determine a monetary amount associated with each unit of pollution emitted. For example, reducing CO2 emissions was valued at $41.80/ton, which considered impacts of climate change on human health, agricultural productivity, property damage, and ecosystems. This might not sound like much, but electricity generation released almost 2000 million metric tons of greenhouse gases in the United States in 2017.3 Health benefits were similarly assigned monetary value, reflecting the predicted transport of pollutants downwind of power plants and the likelihood of populations downwind coming in contact with heightened concentrations of pollutants associated with electricity generation.
Location Impact of Renewables
The research team divided the continental US into 10 regions, pictured in Figure 1, and evaluated the benefits per installed Megawatt-hours (MWh) of wind, rooftop solar, and utility solar electricity generation. The bar graphs in Figure 1 show that location plays a bigger role than type of renewable technology in determining the amount of benefits. Replacing existing technology with renewables would provide significantly more health benefits (blue, green, and orange bars) to the eastern half of the US, whiles climate benefits (red bars) are less location dependent.
This makes sense, given that the benefits are largely determined by the type and amount of primary electricity generation technology that would be displaced, as well as the population density. Benefits are reported on a per MWh basis, so they reflect the benefits that each unit of renewable energy generation can bring, rather than the total amount of renewable energy that can be employed in a region. Figure 2 illustrates how the regions with the largest health benefits to be gained are those using large amounts of coal or those with highest population density. For example, the Northeast uses much more gas than coal, its higher population density downwind of power plants increases its benefits to be gained.
What does this mean for us?
Location matters when it comes to installing renewable energy. While climate effects are largely averaged globally, health impacts of air pollution are very location-dependent. This explains the difference in these benefits in Figure 1. The installation of renewable electricity generation has the ability to offset harmful emissions by replacing fossil-fuel driven generation, but the health benefits will chiefly affect the surrounding areas.
The biggest positive health benefits stand to be gained in regions of the US that rely primarily on fossil fuel (and particularly coal) electricity generation.
So, the biggest impact in overall health can be made by advancing renewables in those areas, rather than in areas (like California and the Southwest) where renewables have already made a sizable impact. That’s not to say that we shouldn’t seek to broadly increase renewable energy generation… but certain areas, like the Upper Midwest and the Great Lakes Mid-Atlantic will feel the benefits of each MWh much more!
Source Article: J. J. Bounocore, E. J. Hughes, D. R. Michanowicz, J. Heo, J. G. Allen, & A. Williams. Climate and health benefits of increasing renewable energy deployment in the United States. Environ. Res. Lett. 14 (2019) 114010. Link
- US Environmental Protection Agency. National Emissions Inventory
- Lelieveld J, Evans J S, Fnais M, Giannadaki D and Pozzer A 2015 The contribution of outdoor air pollution sources to premature mortality on a global scale Nature 525 367–71
- US EPAOCCD2019 Inventory ofUSGreenhouseGas Emissions and Sinks: 1990–2017 Report Inventory ofUS Greenhouse Gas Emissions and Sinks: 1990–2017 (Washington, DC:US EPA) pp 1–675