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June 10, 2020   |   Diesel Technology Forum

Policy Insider

DTF's Comments to the California PUC Regarding Legislation on Emergency Backup Power

California PUC has proposed a proven and reasonable option to incorporate diesel generators into microgrids established to operate during grid outages.

We wanted to share our final submitted comment to the California Public Utilities Commission (PUC) regarding the proposed decision of adopting short-term actions to accelerate microgrid deployment and related resiliency solutions in California - Order Instituting Rulemaking Regarding Microgrids Pursuant to Senate Bill 1339 and Resiliency Strategies, Rulemaking 19-09-009 (Filed September 12, 2019).

Download DTF Comment to California Public Utilities Commission on Microgrid Policy

On behalf of the Diesel Technology Forum, we submit these comments concerning efforts on the part of the California Public Utility Commission (PUC) to develop short term actions to accelerate the deployment of microgrids in the above-captioned action. In summary:

I. Introduction
By way of background, the Diesel Technology Forum is a not-for-profit educational organization whose members include leaders in diesel engines and equipment, vehicle manufacturers and fuel producers. Our organization serves a primary role of education along with the collection and commission of research to raise awareness of the environmental performance of the newest generation of diesel technology, including those that power commercial vehicles and buses, off-road equipment and stationary engines and electrical generating units. More information is available at www.dieselforum.org.

II. Diesel Technology is a Widely Available, Mobile and Proven Technology to Provide Backup Power for Microgrid or Standalone Applications
Communities and businesses proactively seeking backup power capabilities have many options to choose, and diesel offers a variety of unique benefits. Unlike other technology choices, diesel backup units are available as mobile and can be delivered, along with fuel which is widely and readily available, to any location, even those in remote regions. Given other alternatives, mobile generators also provide customers with a cost-effective solution to deliver critical services. These units may be sized for any application while the upfront cost of installing the necessary electrical switchgear to accept a mobile unit is a fraction of the purchase price of any standalone system.
Diesel generators are also one of the only mobile technology choices capable of providing full electrical load and load following capabilities for extended periods of time as envisioned by California’s Public Safety Power Shutoff (PSPS) protocols. This is a key attribute for mission critical facilities that depend on uninterrupted power, and those with life safety requirements such as health care facilities.

III. New Generation of Diesel-Powered Generator Units are Lower in Emissions and Quieter than Previous Generations
Newest models of diesel generators manufactured since 2014 achieve new lower levels of CARB established emissions performance compared to previous generations. The PUC could specify the use of these newer low-emissions diesel units. Since 2018, new technology diesel engines used in mobile electrical power units 15-47 kw meet EPA and CARB low emissions standards for both oxides of nitrogen (NOx) and particulate matter (PM). Depending on horsepower, diesel technologies developed to meet Tier 4 standards can reduce emissions of NOx and PM upwards of 80 percent relative to older generations of equipment manufactured before any emission controls were required.

IV. Diesel Technology Can Provide Effective Backup Power to Sustainable Microgrid Solutions
Over the past decade, the concept of microgrids has been gaining attention. Many municipalities and critical infrastructure owners have been installing sources of power generation that may not rely on grid supplied electricity. Often, these off-grid sources of power generation rely entirely or in part on renewables to provide sustainable sources of power.
In order to be truly resilient, microgrids should still rely on varied sources of power and diesel generators can prove to be a key technology to provide power to critical facilities when renewables are off-line. Natural gas supply can sometimes be curtailed in the event of natural disaster such as fire conditions or major seismic events and battery backup solutions can run out of power without adequate renewable generation for charging. Diesel technology is ready and available today with self-contained portable fueling to maximize portability and provide uninterrupted power to critical facilities.

Communities across the country looking to install microgrids are also relying on diesel technology to provide emergency backup power, often relying on existing backup units. For example, the waste water treatment facility in McKinleyville, CA is relying on existing diesel emergency generators to backstop a battery-backup microgrid. Another wastewater facility in New Jersey recently installed capabilities to draw power from biogas generated on site while relying on the existing bank of diesel generators to provide emergency power. Because sources of biogas may be intermittent, the diesel standby capability is mission critical to make sure the treatment is operating as intended for this New Jersey community and Tier 4 non-emergency generators are selected over customary Tier 2 generators due to longer anticipated outages when they do occur. 

After decades of innovation, the latest near-zero emissions diesel technologies may be integrated into standby units. The Tier 4 emissions standards results in significant emission reductions of fine particles and ground level ozone forming compounds and innovations in diesel aftertreatment technologies are shown to be effective in reducing these emissions. While not specifically required by regulation, customers looking to enhance the environmental performance of their microgrid application have integrated Tier 4 diesel standby generators. Below are a few case studies of integration of Tier 4 standby units in microgrid applications for critical and not-so-critical facilities:

No single source of renewable power can guarantee supply of continuous uninterrupted electricity through a microgrid. A smart solution takes advantage of unique capabilities of ready and available fuels and technologies and integrates those together. Wind and solar can be combined with near-zero emissions capabilities of proven diesel generators to make sure critical and not-so-critical assets keep functioning in the event of a severe weather event or power disruption.

V. Use of Renewable Fuels in Diesel Units Can Deliver Further Benefits in Emissions and Carbon Reduction
The original diesel engine patented by Rudolph Diesel over a century ago was designed to operate on biofuels. Today, that still holds true as diesel engines can operate on 100 percent renewable diesel fuel and blends of high-quality biodiesel.
Diesel generators may also operate using these renewable fuels to deliver significant greenhouse gas reductions. Biodiesel and renewable diesel fuel are considered advanced renewable fuels by the U.S. Environmental Protection Agency and as such, they reduce greenhouse gas emissions by at least 50 percent. Renewable diesel fuel that is currently available and in widespread use in public and private fleet applications in California is demonstrated to reduce greenhouse gas emissions by upwards of 80 percent. As shown in the figure below, the California Air Resources Board estimates that biodiesel and renewable diesel fuel have reduced far more greenhouse gas emissions than the fleet of electrified cars, trucks and buses. The switch to these fuels does not require the purchase of new engines or the installation of costly charging or refueling infrastructure.

Municipalities across California are taking advantage of these low-cost options to reduce greenhouse gas emissions from the fleet of standby diesel generators. The City of Oakland is fueling the city’s fleet of heavy-duty trucks, equipment and standby diesel generators exclusively with renewable diesel fuel. This includes large standby units located in police stations including the City’s 911 call center and also the fleet of mobile diesel generators.

V. Conclusions
Selective grid outages as a risk management strategy during fire season, while inconvenient, is a proven strategy to protect the greater good of life and property. The electric utility has proposed a proven and reasonable option to incorporate diesel generators into microgrids established to operate during grid outages.

Any emissions from the intermittent use of these diesel-powered units will be incidental in the scheme of the emissions inventory and emissions from massive wildfires like those that have occurred in past years, particularly when weighed against the economic and life-protection value of having continuous electrical power.

The utility can take steps to further mitigate the environmental impact from the use of diesel generators that will operate for extended outages, by specifying conditions that prescribe the use of only the most current generation of near zero emissions diesel technology and also through the use of renewable biodiesel fuels.

Microgrids integrate the “best of both worlds; renewable energy sources that we want, with the reliability that we need." Diesel technology is a prudent choice to provide critical standby power to microgrid applications across California and should be approved for this application. Diesel is a trusted technology that has demonstrated effectiveness for generations, and diesel technology is well suited to backstop future sustainable microgrids. The latest near zero emissions Tier 4 diesel technologies along with advanced biofuels, such as renewable diesel fuel and blends of high-quality biodiesel, may play an important role in boosting the sustainability credentials of future microgrid applications.

Thank you for the opportunity to provide these comments concerning the capability.

Allen R. Schaeffer Executive Director


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Allen Schaeffer
Executive Director

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