MITEI postdoc Patrick Brown and Senior Lecturer Francis O’Sullivan analyzed utility-scale solar photovoltaic (PV) arrays. They found that they are an economic investment across most of the United States when climate and health benefits are taken into account. Their results firmly present the importance of giving precise price signals to consumers and generators. And perhaps the most important find was that different regions reap higher economic benefits than others. So, it would be ideal for governments to adopt policies that reward the installation of solar arrays where they’d bring the most benefit.
The researchers conducted this analysis because the cost of PV arrays may have fallen, but the value of PV power has as well, especially in areas that have installed a substantial PV generating capacity. As more PV generators come online, the price of electricity drops, meaning operators of utility-scale PV systems make less. However, since the PV arrays cost less, to begin with, the drops are balanced. Furthermore, taking into account the savings from health and climate improvements, the economic benefits increase. Improved public health and reduced emissions result in massive savings on medical care.
These factors were complicated to calculate, however, because many coal-fired power plants were required to install emissions-control systems in some regions but not others. Meaning, the decline in air pollution wasn’t equal nationally. Also, for the areas that had improved air quality, the potential health benefits of PVs from offsetting coal generation was diminished. So, what the researchers did to get an objective analysis was to calculate the would-be CO2 emissions if there were no emissions-control systems in place anywhere. That way, every region got the same interpretation of their PV arrays to offset fossil fuels.
The analysis assessed the annual benefits and costs of PV power from 2010 to 2017 across the US power grid. The team focused on six “independent system operators” in Texas, California, the Midwest, the Mid-Atlantic, New England, and New York. They calculated how much electricity each generated along with the revenue that created and the avoided climate change and health costs linked to the displacement of fossil fuel emissions.
The results revealed that the value of PV generation varied significantly from place to place and over time. For example, the public health benefits were higher in New York than in the Midwest, where there’s lots of coal generation, and it also declined over the study period overall as measures to reduce emissions were enacted. These findings underscore the importance of considering the climate and health benefits in addition to the market revenues.
Brown said:
If you’re going to add another megawatt of PV power, it’s best to put it where it’ll make the most difference, not only in terms of revenues but also health and CO2.
The researchers recommend policies that provide incentives for installing PV systems where they’ll be most valuable. To help with this, the analysis offers guidance by identifying “hot spots” where PV generation is especially relevant. They also made their database and computer code openly available because conditions are continually changing on power grids and electricity markets. This way, anyone can readily use them to calculate updated estimates of the net benefits of solar PV power.
