By James Fair, PE, Scott Henriques, PE, LEED AP, CEM, Della Rae Donahue
For several years now, many municipalities have been facing the fact that their public works facilities have become outdated and sometimes undersized, inefficient, and out-of-code. The fact that many of these facilities need updating or replacement provides a perfect opportunity to take a fresh look at the Department of Public Works (DPW) and the facilities that they use for their day-to-day operations.
While public works departments are responsible for maintaining our communities, they have sometimes been associated with the negative aspects of an unsustainable community framework. This seems counterintuitive to the entity responsible for bringing its citizens clean drinking water, providing safe disposal of wastewater, properly managing waste and recycling materials, and maintaining our recreational parks and fields. This can create a disconnect between public works and our citizens.
Many forward-thinking DPWs, however, are trying to bridge this gap, but in today’s fiscal state, it can be like swimming upstream. Many communities are hesitant to support DPW initiatives because of a false narrative that they are simply a maintenance crew and do not need much more than a “barn” or a garage. In reality, DPWs manage the full range of town assets, but our society’s general misconception of this municipal agency can make it difficult to gain financial support.
The physical structures and site features of DPW facilities themselves though provide the raw material from which sustainable design initiatives can be implemented. There are extensive criteria that apply to buildings and site design, and while we could develop a whole seminar on the wide range of opportunities for DPWs to be more sustainable, we will focus here on one - the actions and tools to be considered when upgrading DPW facilities as municipalities electrify their vehicle fleet and their buildings.
How Will Fleet Electrification Impact DPW Facilities?
Fleet electrification is evolving rapidly as many communities are eliminating their fossil fuel-based fleets and replacing them with alternative fueled vehicles to reduce their impacts on the environment. Electric vehicles (EVs) are currently the most popular type of alternative fueled vehicle being used. There are other alternative fuels such as compressed natural gas (CNG) and hydrogen, but these technologies have not been adopted as quickly as EVs, and it is anticipated that EVs will remain the most common type of alternatively fueled vehicle for the foreseeable future.
Electric sedans, school buses, and transit buses are actively being used and becoming more popular, but the use of battery powered pick-up trucks and large trucks such as fire engines are also starting to be more prevalent. As battery technology improves, even larger vehicles and trucks are anticipated to be converted to EVs as well. As EVs gain an increasing foothold in the market, it is important for DPWs to start planning to redesign their facilities so that they have the necessary infrastructure to maintain EVs.
Because EVs do not have the same type of engine or equipment as fossil fuel-powered vehicles, their maintenance requirements are different, and these changes need to be addressed with the design of new or upgraded DPW facilities. Examples of new features to be considered include increased power requirements, EV charging stations, battery storage and maintenance space/equipment, maintenance fluid changes, and increased fire suppression requirements, along with other considerations. This deserves a closer look.
Because EVs do not have an internal combustion engine (ICE), they do not need traditional fuels (gasoline and diesel) or motor oil, which results in a significant reduction in the amount of fuel and maintenance fluids that need to be managed. Please note, however, that there are still some fluids that are required, such as gear oil, coolant, and windshield washer fluid, to name a few.
Fleet facilities switching to EVs will require charging stations in various locations such as the maintenance bays, vehicle and equipment storage areas, and parking areas for visitors and employees. The battery systems - or energy storage systems (ESS) as they are often called - also need to be managed and maintained. The batteries will need space for storage, cleaning, inspection, and maintenance inside the building. Separate storage space for damaged batteries, preferably in an area other than the main facility, will also be needed due to fire hazards. Batteries also require specialty equipment to move them throughout the facility and to store and properly inspect/maintain them.
It is anticipated that vehicle fleets will transition to EVs over a period of time and that the maintenance facility will need to accommodate both ICE-type vehicles and EVs in the interim. Direct and indirect exhaust capture systems will not be needed for EVs while indoors, which will reduce building energy needs, but will still be needed as fossil fuel vehicles are phased out. As discussed above, fuel and maintenance fluid needs will decrease as more EVs are brought into the fleet, however there will be a corresponding increase in electrical power requirements, EV chargers, and battery management space and maintenance equipment. The mechanics will also need to be trained to maintain the EVs.
Due to the significant electrical power needs, new or upgraded DPW maintenance facilities will need to have their electrical infrastructure carefully planned out to allow it to be upgraded in the future as the power demands increase with the use of EV vehicles. Of course, the increased use of EVs will help drive the potential for sourcing renewable energy, as will the increased use of electric heat for the facility, as described further below. These efforts will greatly increase the environmental sustainability of DPWs.
Doubling Down on Electrification
The push towards building electrification is being driven by electric grids becoming more renewable, ever more stringent building energy codes, mandated utility incentives, and a strong commitment by communities to have a carbon neutral footprint. Complete electrification of the actual public works building is being considered by many, and actual implementation is starting to gain traction.
Highly efficient, all-electric building HVAC and lighting systems, strategically implemented with proper energy management strategies, will minimize energy consumption while providing the required lighting, heating, cooling, and most importantly, ventilation systems that provide safe, comfortable, and productive environments.
Some example system types that are particularly suited to reducing energy use for public works facilities include:
- Radiant heating systems (floor and ceiling) that reduce the temperature required to maintain comfort. These are especially effective in large spaces such as the maintenance bays and vehicle storage areas which also have high ventilation requirements when fossil fuel vehicles are still present.
- Radiant cooling systems can be considered in warm, arid climates.
- Air-to-water heat pumps (AWHP) allow the use of highly efficient, low-temperature hot/chilled water for heating/cooling systems.
- Air-to-air, high efficiency, heat pumps (AHP), both traditional and variable refrigerant flow (VRF), are a less expensive capital expenditure than AWHPs. However, they are a slightly less efficient as they preclude the use of efficient electrically fueled radiant systems.
- Dedicated outside air systems (DOAS) with non-cross contaminating energy recovery mitigate the substantial exhaust requirements in maintenance bays servicing fossil fuel powered vehicles.
- Air curtains reduce energy losses when garage door bays are open.
- Heat recovery systems for electric battery chargers can replace some heating energy.
- High-volume low-speed (HVLS) fans in high bay areas are a highly efficient means of mitigating thermal stratification in winter months and enhance natural cooling in the summer months.
- LED lighting, occupancy sensors, and natural lighting minimize energy needs for lighting and reduce cooling energy needs in summer.
- Modern Building Management Systems (BMS) provide almost unlimited possibilities to implement energy reduction strategies for all building systems.
Alternative energy sources such as solar thermal, photovoltaics (PVs), Renewable Energy Certificates (RECs), wind, and even geothermal systems can be considered to eliminate the reliance on fossil fuel-generated electricity and provide a true carbon NetZero facility. The upfront capital costs associated with the design and construction of these systems can be substantial but will typically be amortized over time. Once paid off, the cost of energy needed for the building would be maintenance-related only, and the actual energy would be free.
With a resilient and sustainable DPW designed and built in a community, the positive impacts have the power to create a ripple effect throughout the various other municipal buildings and within the individual lives of each resident. A sustainable DPW will not only avoid being seen as part of the problem but could also be seen as part of the solution. With an example set, other community projects that embody the same values of sustainability may emerge and solidify true wellness and resiliency in which everyone (and everything) benefits.
For additional information on sustainable public works facilities, we kindly refer you to:
James Fair, PE can be reached at (978) 573-4063 or email@example.com
Scott Henriques, PE, LEED AP, CEM can be reached at (978) 587-1774 or firstname.lastname@example.org
Della Rae Donahue can be reached at (508) 203-4208 or email@example.com
This article was originally published in APWA Reporter, September 2022.