Smart opportunities range from smart irrigation controls that impact water to environmental sensing that help improve the lives of Mesa citizens. Mesa (and Maricopa County’s) commitment to improving air quality and reducing air pollution can be enhanced through multi sensor nodes that detect a wide variety of conditions that can inform city leadership of adverse events that affect the environment. Additionally, smart Infrastructure sensors that produce data that inform advanced control systems can impact green buildings and energy efficiency programs that protect the natural environment.
Food - to - Energy Anaerobic Waste Digester Pilot
Project The City conducted a feasibility study to determine the benefits of a a food to energy Pilot. Anaerobic digestion is a natural process where organic materials break down in the absence of oxygen producing a substance known as biogas, which is made up of methane and carbon dioxide. A waste digester stimulates this process on waste products and traps the methane so it can be converted into clean energy. Food waste, according to the EPA, is the second largest category of municipal solid waste (MSW) sent to landfills in the United States. Food waste is easily biodegradable and according to a study by East Bay Municipal Utility District, food waste has up to three times as much energy potential as biosolids.
Benefit to the City Converting biogas will allow the City to mitigate negative climate change while producing a clean energy source. The City will see a reduction in waste in our landfills and an economic benefit in reduced energy costs.
Current Status The feasibility study is complete. The final report to the City Council includes specific steps that must be taken to implement a biogas to renewable natural gas (RNG) system at Northwest Water Treatment Plant. Council will determine if the City will move forward with a phased approach.
Facility automation uses smart infrastructure to produce data that improves building operations, supports resiliency and realizes energy efficiency that supports Mesa’s goals to protect the natural environment.
Smart sensors, advanced controls and a robust energy management system (EMS) optimize equipment run times, temperature set points and performance. The EMS uses information it collects each day to make better decisions, actually using the data to “learn” how to run the equipment better! For example, based on the temperature outside and the history of how long it takes the building to cool to a comfortable temperature, the EMS selects the best time for the equipment to turn on each morning. Gone are the days of guesswork.
The EMS can monitor HVAC, lighting, security, life safety and other building functions. It also allows technicians to remotely check on equipment and manage performance so that problems can be diagnosed quickly. Engineers can analyze data in real-time to identify odd spikes in energy use and trends so they can implement energy conservation measures.
A lesson in savings
The cool air of the Red Mountain Branch Library's HVAC system,unbeknownst to most library guests, includes one of the key initiatives of the Mesa Smart City plan, building automation.
The library’s new Energy Management System (EMS) uses smart technology to improve energy efficiency and equipment performance. The system is demonstrating positive results, averaging about 22 percent saving. At about 0.085 cents per kWh (from SRP), the EMS at Red Mountain Library has saved more than $1,200 monthly. That trend only appears to be getting better!
To expand the savings, the library just completed its chiller system replacement project. Wasteful, inefficient chillers that used 100’s of gallons of water to cool the Library were replaced by new air-cooled units that require no water and use significantly less energy. The result in less electrical usage throughout the day when electrical rates are the highest and less water usage.
The estimated potential for annual utility bill savings from this project is in the range of $10,000 to $15,000 per year with an estimated annual energy usage savings in the range from 125,000 kWh to 170,000 kWh per year. This project has the potential to reduce greenhouse gas emissions from 87 to 119 metric tons annually, which is equivalent to removing 19 to 25 passenger vehicles from the road. Saving both water and energy, the new systems installed provide a comfortable environment for people of all ages enjoying the library.
The Red Mountain Library Project is just one step in this “smart” journey. The City will continue to expand these savings to additional buildings throughout the City to reduce costs and consumption, makings a smarter and more viable Mesa.
The City has partnered with Trane to have the HVAC in 60 City buildings automated. 17 buildings are online and/or in process as of 2020, including the Mesa Convention Center, City Council Chambers, Broadway Recreation Center and Mesa City Plaza.
Additional phases will expand the automation to include other cost saving items such as lighting, security and other life saving systems. The result will be City facilities that run more efficiently. cost less to operate and help reduce the City's carbon footprint to ensure a vibrant environment for generations of Mesa residents to come.