Front matter for Renewable Energy Technologies and Water Infrastructure

To gear up on renewables, subsidies on fossil-fuel energy applications must be significantly reduced and an immediate boost to RE funds should be provided; and this approach would help safeguard humankind from ongoing uncertain weather patterns and havoc. The federal agency efforts, such as by the Bureau of Land Management (BLM), Bureau of Ocean Energy Management (BOEM), and Federal Energy Regulatory Commission (FERC), based on the effective RE legislative actions, are appreciative (to date) in terms of the production and consumption of RE at more than 9.5 quintillion J (9.0 quadrillion Btu) and the resultant significant reduction of greenhouse gases (GHGs). Moreover, the Energy Independence and Security Act (EISA 2007) has been instrumental in the production of renewable fuels (Chapters 1 and 2).

Chapter 3 contributed by internationally renowned author highlights that the use of soybean oil (one of the vegetable oils) stood at 57% (in 2019) to produce biodiesel, and the market opportunity was rated at 6.8 billion L (1.8 billion gal.) per year. However, the long-term goal for clean renewable fuels was set (in 2007) at 136 billion L (36 billion gal.) per year.

Chapter 4 includes the following recommendations: the small-stream micro-hydropower generation technologies are “mature technologies,” facilitating distributed or decentralized RE technology and providing a positive environmental impact compared with that of large-dam hydropower; and they must follow the local, state, and national environmental and energy regulatory guidelines to accomplish potential success in micro-hydropower.

According to the current and historically well-known sources, Chapter 5 fortifies the effective use of municipal wastewater sludges (the by-product solids as generated from wastewater to clean water processing), fats–oils–grease (FOG) feedstocks, vegetable and food wastes, livestock manure(s), and other (highly) biodegradable municipal and industrial wastes to the successful operation of biogas-to-energy-distributed RE systems. Also, the economics of biogas-to-energy systems are proven worldwide and are a guaranteed positive cash flow (with a short payback time). Most importantly, biogas-to-energy systems also provide pathways to making environmentally friendly by-products and are globally required in the “circular economies.”

Fuel cell development and operation based on wastewater systems has been rapidly advancing, and current research results are highly utilized worldwide for effective and immediate applications. Chapter 6 addresses the key requirements of various fuel-cell technologies, including microbial fuel cells (MFCs). The challenges—production, storage, and supply—posed to biohydrogen infrastructure are elucidated, where there is rigorous research requirement for fermentation technologies, control of fouling, and the development of effective catalysts and electrode materials for fuel-cell operation(s). The authors emphasize on the use of MFCs for the potential NetZeroEnergy operation of wastewater infrastructure.

Desalination operations are witnessing an unprecedented growth globally because of increased freshwater demands. Specifically, RO processes or technologies that dominate this field help make freshwater from brackish, saline, and clean effluent (to name a few) water resources. In Chapter 7, the author clearly identifies the need for research on membrane distillation and adsorption desalination technologies for harvesting solar energy and waste heat for (fresh) water production. The author also outlines the priority for developing environmentally responsible and RE-integrated desalination systems.

Geothermal energy has been playing a significant role in HVAC systems globally. In Chapter 8, the scientist authors elucidate on geothermal energy and its commercial challenges, and the required improvements. It is vital to note that current improvements focus on implementing enhanced geothermal systems (EGSs) and binary power plants that will work based on “lower geothermal resource temperatures,” and the scientists are outspoken on “geothermal energy has the potential to solve many of the world's energy problems.”

The application of RE systems with resilience is now critical and is a case for the (immediate) future. This wind energy expert in Chapter 9 unequivocally states, “The capability to implement resilience in the built infrastructure to tolerate energy loss as well as the outcome of natural and man-made disasters including highly volatile aspects of climate change, is key to establishing criteria for resilience in critical water infrastructures.” The current advancements include hybrid wind energy systems that can well support microgrids and can also provide real-time data on water security and availability.

Need for developing significant level(s) of energy—to operate high standard water and wastewater treatment trains—owing to polluted resource water and spent water and the resultant unwanted GHG emissions of fossil-fuel firing for power generation is critical and needs a clear mandate. It is important to note the critical role of RE systems in the context of the current climate patterns, the loss of water due to the ever-increasing impervious areas in worldwide development activities, and the associated droughts. In Chapter 10, solar energy is detailed for applications to both water and wastewater systems and infrastructure.

Current need for environmental quality monitoring is seen to be enormous, and, so, Chapter 11 addresses the importance of water quality monitoring through the use of RE systems. It is not an easy task to list out the various requirements for such monitoring, and this is where the author's effort in writing such a chapter becomes commendable. The large wireless monitoring networks [operating the Internet of Things (IoT) for data collection and SCADA reporting] for water quality monitoring can make use of in situ RE sources, such as solar power and MFCs. The emphasis on the use of RE-based monitoring network systems also comes with a caution on security requirements.

Chapter 12 provides real-time project examples of water infrastructure integrated with solar and/or wind energy systems. It is clearly shown that RE systems can be used for both demand and supply side operations of water infrastructure. Based on the proven applications detailed in the chapter, the authors are insistent on RE integration with water infrastructure so as to remove the dependence on fossil-fuel-generated power.

Central State University, Wilberforce, OH

Electric Power Research Institute, Palo Alto, CA

Gannon University, Erie, PA

Green Water-Infrastructure Academy, Washington, DC

Louisville Parks and Recreation, Louisville, KY

Manhattan College, Riverdale, NY

Mississippi State University, Mississippi State, MS

National Renewable Energy Laboratory (NREL), Golden, CO

Portland State University, Portland, OR

RC-WEE Solutions LLC, Dublin, OH

Rensselaer Polytechnic Institute, Troy, NY

Ritter Engineering, Elkton, MD

Rose-Hulman Institute of Technology, Terre Haute, IN

South Dakota School of Mines and Technology, Rapid City, SD

Star Sailor Energy, Inc., Cincinnati, OH

University of Delaware, Newark, DE

University of Illinois at Urbana-Champaign, Urbana, IL