All backup combustion energy sources have environmental side effects. Which one is less harmful?
Editor’s note: The massive blackout in Texas in February 2021 left many people feeling insecure about reliable utility service. This is the third article in a series of five about the rapidly growing number of backup power systems being installed in Austin-area residences.
Ray Defroug, a retired technical coach for Applied Materials, just completed his generator installation in July. His all-electric home in the Austin suburb of Buda is being offered by Pedernales Electric Cooperative (PEC). Winter outages manifested differently for the Austin Energy Service Area. Instead of going days at a time without electricity, there was a decrease in energy consumption of about a week (usually six hours at a time) followed by several hours of energy consumption.
Fortunately, he had a wooden fireplace that allowed enough heat to survive. The lowest temperature inside his house during the outage was 48 degrees.
He’s dealt with shorter PEC outages before, and he doesn’t want to put up with that kind of uncertainty anymore. Its generator will enhance self-reliance. “For my convenience,” he said, “I don’t want to rely on a system that’s on the verge of collapse.”
While DeVreugd and many others are rushing to install standby generators, the environmental impacts of hundreds, or perhaps even thousands, of eventual standby generators in the greater Austin area have not been considered, to my knowledge, and will be addressed in this article.
All combustion engines and engines lose huge amounts of energy to waste heat loss, which is, to some extent, a proxy for carbon emissions. Natural gas steam turbines used at peak summer load, for example, are typically 31 percent efficient, after transmission and distribution (T&D) losses.
The best-in-class combined-cycle natural gas power plant is 60 percent efficient, after transportation and development losses.
It is estimated that during peak demand, T&D losses can be much higher.
However, a residential full load standby generator is generally 16 to 25 percent efficient. There are no T&D losses for on-site generated electricity. However, centralized power is more efficient than standby units.
However, in the context of emergency alternatives, standby generators often replace the need for portable gasoline and diesel generators, which may operate at an efficiency of 15 percent or less. In winter, they can replace stoves, which are 10 percent efficient or less.
The Environmental Protection Agency, in its National Ambient Air Quality Standards, identifies six common air pollutants as “critical air pollutants” that can harm human health and the environment and cause property damage. Utility-scale power plants emit significantly fewer emissions than portable on-site gasoline and diesel generators. Emergency generators are only designed to run a few hundred hours a year, but those hours combined can add up to significant pollution.
In California, for example, blackouts have become common in certain parts of the state due to the fire hazard from electrical lines. Since this dilemma would take many years to fix, about one in eight customers affected in this fire-prone area have portable gasoline and diesel generators.
A draft report by the California Air Resources Board estimated that 125,000 portable gasoline and diesel generators running for just 50 hours during October 2019 created an estimated 166.4 tons of nitrogen oxides (toxic gases) and 19.4 tons of particulates and microscopic particles of suspended solids or liquids. In air that can be inhaled into the lungs, causing adverse health effects.
By comparison, according to the Texas Environmental Quality Commission, 84 tons of nitrogen oxides and 45 tons of particulates were emitted by the 696-megawatt Austin Energy power plant in Sandhill during the whole of 2019.
However, the natural gas and propane backup generators discussed in this article run on inherently cleaner fuels, and their emissions are not as high.
One must also consider other alternatives that emergency standby natural gas and propane generators as well as portable gasoline and diesel generators replace: to use); And in extreme cases (contrary to all common sense), barbecue pits and non-ventilated propane heaters are brought indoors.
Stoves may keep you alive when the power goes out but they are ruthlessly polluted.
There is not a lot of publicly available data on the US market for portable generators besides the California estimate mentioned above. A New Jersey survey estimated that 30 percent of people over the age of 18 reported owning portable gasoline and diesel generators in 2016. Generac, which makes both portable and standby generators, estimated that 16 percent of U.S. homeowners had equipment portable.
Even more worrying is the use of portable generators in developing countries where central electrical systems are likely to operate poorly. A 2019 report by the World Bank Group’s International Finance Corporation estimated that these dirty diesel and gasoline standby generators (sarcastically referred to as “BUGS”) were likely installed at 20 million or 30 million sites in 167 developing countries.
The pollution from this fleet of BUGS was equivalent to the pollution of 700 to 1,000 coal plants, with fuel costs in the range of $28 billion to $50 billion annually. The machine is generally operated more often due to malfunctioning central electrical systems whose outages can reach thousands of hours per year.
In sub-Saharan Africa, BUGS accounted for most of the toxic gases nitrogen oxide and PM2.5, which are fine particles that can be inhaled into the lungs and can cause adverse health effects. These emissions are equivalent to 35 percent of the emissions from the entire transport fleet. Unlike vehicles, generators were more likely to be close to homes and buildings, and thus have a greater negative impact on people’s health.
Dangers of Portable Generators on Site
A report published by the US Consumer Product Safety Commission in 2020 estimated that between 2009 and 2019, at least 686 deaths were attributable to carbon monoxide (CO) poisoning from combustion engine generators. Another 40 deaths from carbon monoxide poisoning were attributed to combustion engine generators used with other combustion-driven products (eg, portable heaters). That’s an average of 66 deaths per year during this study period. Only six of these generator accident deaths were from standby generators; The rest resulted from portable equipment.
The Texas Department of Health counted at least 498 CO2-related injuries in Texas through mid-February 2021 and attributed 60 of them to generators.
Many new portable gasoline and diesel generators are now being built with one or two CO2 safety features.
One standard, ANSI/PGMA G300-2018 certified for safety and performance, applies to all portable generators of 15 kW or less. Requires carbon monoxide detector and auto shut-off feature if gas exceeds 800 ppm peak or 400 ppm within a 10-minute period.
A second, more stringent standard, ANSI/UL2201 certified for carbon monoxide safety, not only includes a shut-off feature but also cuts emissions from the engines themselves to 400ppm or 150ppm over a 10-minute period. Some Ryobi and Echo models are built to this more stringent standard.
While both standards are safer, they are not foolproof, especially if the equipment is operated in or near buildings.
Environmental impacts, both good and bad, will result from consumers’ purchase and use of standby generators.
This is the third in a five-part series on how and why Austinite buys backup power systems. I hope you’re interested in Part 4: Laws and Sausage: Has the Legislature Fixed the Texas Power Grid?
Confidence Indicators: Paul Robbins is an environmental activist and consumer advocate who has lived in Austin for nearly five decades. He is a newspaper editor Austin Environmental Guide, a reference book on environmental issues, products, services, and organizations in Central Texas. The publication has been made free to the public since 1995, and can be accessed free of charge online.