DEQ is considering whether Type II diesel generators, currently allowed for emergency use only, can be used during planned outage events. Until now, these generators could only be used in the case of “sudden and reasonably unforeseeable events” or maintenance. 

Type II diesel generators, one of the most polluting forms of energy generation, were only ever meant to serve as backup power in emergency situations.  They emit emissions that can be harmful to public health and contribute to the formation of ground level ozone, including fine particulate matter (PM10 and PM2.5), carbon monoxide (CO), nitrogen oxides (NOx), sulfur dioxide (SO2), and volatile organic compounds (VOC).

According to the latest State of Global Air 2024 Report, air pollution was responsible for 8.1 million deaths worldwide in 2021, making it the second leading risk factor for death globally, surpassing tobacco and poor diet. This includes 709,000 deaths among children under five years old, where it ranks as the second-leading risk factor after malnutrition. The health impacts are extensive, with noncommunicable diseases such as heart disease, stroke, diabetes, lung cancer, and chronic obstructive pulmonary disease (COPD) accounting for up to 90% of the disease burden from air pollution. Long-term exposure to pollutants like ozone and nitrogen dioxide contributes significantly to these deaths, with ozone alone linked to an estimated 489,000 deaths globally in 2021. 

Tier IV generators should have been installed for planned outages..  Since we now know about utility needs for more extensive use of the generators, consider installing only Tier IV generators for future data centers.  Different types of generators have different impacts and rules associated with them. The difference between Tier IV and Tier II generators is that Tier II generators are typically only used for short periods of time and have weak emission standards, whereas Tier IV generators can be used for much longer periods of time, even as the primary power source of a facility, and have significantly stricter hourly emissions standards.  Emergency generators only need to meet Tier II emission standards because of the limited amount of time that they are expected to be used. 

Because of the health threats to Virginians from running Type II generators, DEQ should continue to prohibit non-emergency use.  For planned outages Tier II generators can be replaced with Tier IV generators either temporary or permanently.  Only if it can be proven that Tier II generators can be retrofitted to Tier IV pollution standards should DEQ allow their non-emergency use.