The landscape for alternative energy technologies is rapidly changing. More and more consumers and businesses are turning to alternative energy sources and technologies. Developments in the field are proliferating at an ever-increasing rate, raising new questions about safety and reliability.
These new applications are introducing different challenges for fire protection professionals that require a higher level of attention. New approaches are emerging for handling society's energy supplies such as distributed energy resources and power isolation/shutdown requirements. These are causing a reevaluation of the relevant codes and standards.
These applications are manifesting themselves in all types of settings. For example, within the built infrastructure these include multiple types of occupancies (e.g.,commercial, industrial, residential) and include non-building applications such as transportation, as well as combinations thereof, such as an electric vehicle connected to a charging station in a commercial parking structure.
UNDERSTANDING ALTERNATIVE ENERGY AND ALTERNATIVE FUELS
Alternative energy is a relatively broad concept whose precise definition partly depends on the specific context in which it is used. This includes recognition of baseline energy sources from which "alternatives" are measured. The predominant use of fossil fuels for many applications provides the de facto baseline from which today's alternatives are typically compared.
The various definitions of alternative energy in mainstream literature are often rooted in renewable energy sources. For example, the concept of alternative energy includes: "energy that is derived from sources that do not use up natural resources or harm the environment",1 or "energy sources that have no undesired consequences"2 (such as fossil fuels or nuclear energy), are renewable, and considered to be 'free' energy sources. The sources of energy that are normally considered to be "alternative,"and which are the most commonly found among information sources addressing this topic, include the following: biopower, geothermal, hydropower, wind, and solar.
Sometimes specific alternatives are precisely defined in various public policy programs. This may contribute to the perceived confusion on the use of the term "alternative" when talking about alternative energy.
An example of the use of legislative requirements to define "alternative fuels" is the classification system used for motor vehicles that utilize gasoline or diesel fuel. This is set by the U.S. Environmental Protection Agency through the Clean Air Act Amendment of 1990 and Energy Policy Act of 1992, which recognize the following 10 classes of alternative fuels: (1) electricity; (2) hydrogen; (3) natural gas; (4) propane; (5) methanol; (6) ethanol; (7) reformulated gasoline; (8) clean diesel; (9) coal-derived liquids; and (10) biologicalmaterials.3,4 In this case, some of the alternatives are fossil-based fuels that are not recognized as renewable sources.
TRADITIONAL SOURCES OF ALTERNATIVE ENERGY
In today's society, alternative energy sources are most often considered to include: biopower, geothermal, hydropower, wind, and solar.
Biopower is the derivation of energy from bio-products. This approach is not new, and historically includes the use of wood, peat, and other bio-materials. In modern society, biomass includes pulp and paper, municipal solid waste, landfill gas, corn-based ethanol, and similar fuels. The latest technological focus with biomass is on feedstock logistics, fuel sustainability, flue gas clean-up, and integration with other biomass applications such as integrated bio-refineries.
Biopower involves bio-based materials that might stand alone or be blended with conventional fuels, such as ethanol blended gasoline used with today's motor vehicles. Different fuels have different physical characteristics and present different fire protection challenges. For example, the water solubility of some liquid biomass fuels requires modified protection methods such as specialized fire fighting foams.
Geothermal is an alternative energy source that utilizes natural heat within the earth for power generation. This is typically accomplished through the use of injection and production wells set into and out of the earth as a closed circuit steam generation loop.
A typical geothermal power plant involves capturing steam (or other media) from beneath the surface of the earth and channeling it through turbines or other machinery for the generation of power, such as electricity. These plants would have hazards similar to conventional electrical power generating plants (e.g., lube oil system), but without the combustion process and its related hazards.
Hydropower is an alternative energy source with noteworthy historical roots. The great industrial mills of the industrial era, for example, were typically built on rivers and other natural waterways to capitalize on mechanical and electrical power generation. Today, hydro electricity is a direct contributor to the overall energy supply.
This is expanding beyond conventional applications of river ways, and involves tidal flows and other marine and hydrokinetic applications. Like geothermal, the fire protection challenges of hydropower tend to be less than that with other power generation facilities that require a combustion component as part of their power generation process.
Wind provides a clean and renewable power generation source that has been increasing in use through the proliferation of localized wind turbines. In their simplest form, these are electrical generators mounted on top of a tall structural support tower and equipped with large wind propellers. Larger wind turbines can exceed 2 MW per unit, and they are found both in separate installations and in groups within a wind farm facility.
The wind turbine unit itself presents the same fire protection challenges as an electrical generator in other installations, albeit at an elevated and less accessible location. Wind turbines do, however, present appreciable structural load considerations when installed on or near a building. Structural integrity is a serious consideration among other factors during building design or retrofit. These wind turbines are typically located on top of a tall structural tower and well removed from exposures if a serious fire occurs, though outdoor fires and similar exposure concerns are a possibility during a serious fire involving a wind turbine.
Solar power is an other technology that has proliferated in recent years, in part because of improved manufacturing methods that are making this approach realistically affordable and readily available. The three basic means of capturing the sun's energy are: passive solar (i.e., capturing the sun's energy in building design and construction); solar thermal (i.e., sunlight converted to heat); and photovoltaic (sunlight converted to electricity).5
Of particular interest from a fire protection engineering perspective are solar thermal and photovoltaic systems. Solar thermal systems involve the heating of fluids in a circulating loop system, and they can add appreciable weight load to a structure. They can also introduce possible hazards to emergency responders such as roof top tripping and scalds from hot liquids.
On the other hand, photovoltaic systems that convert sunlight into electrical energy present certain inherent hazards beyond the concerns with solar thermal systems. A critical consideration for emergency responders and others is that photovoltaic panels are electrically "on" when exposed to sunshine and other light. Power isolation is a technical challenge during an emergency, and complete power shutdown is normally not an option when exposed to sunshine.6
For all types of solar systems, consideration needs to be given to maintaining full access by fire fighters on rooftops and on other sections of a building where firefighters operate during an emergency situation. Advancing solar technologies now include devices beyond traditional panels, such as photovoltaic fabrics and films that can be installed in any orientation (e.g., on a vertical surface) and that can introduce questions concerning flame spread. New products also include building components such as photovoltaic roofing shingles and tiles, which present hazards to firefighters and others that are not readily obvious.
THE BIG PICTURE
The societal advantages of alternative energy sources such as biopower, geothermal, hydropower, wind, and solar are appreciable, and any inherent hazards of these technologies can be readily managed. The use of these technologies follows two general tracks: smaller individual applications, and large-scale power generation facilities.
Wind and solar are the predominant technologies that are proliferating with smaller individual applications on separate buildings. This is creating challenges on the electrical grid as a result of distributed power supplies. Some systems, such as photovoltaic installations on the roofs of large mercantile stores, can create significant power generation equal to a small power generating facility. These require special attention by fire protection engineers and emergency responders alike.
When alternative energy approaches are used in a centralized manner for large-scale power generation, they present fire protection challenges that are similar to conventional large-scale power plants for engineers and emergency responders. For example, emergency responders might approach a wind farm or concentrated solar installation with significant pre-planning and in close coordination with the site owner and/or utility, similar to how they would approach a conventional power plant in their jurisdiction.
Interestingly, certain alternative energy applications are the power source of choice for some emergency management and emergency response applications. For instance, the use of solar power for emergency preparedness and disaster planning is an obvious application of alternative energy independent of the electrical power grid. An intriguing approach used in California is the installation of fire apparatus roof-top photovoltaic systems to accommodate deployment overlong periods of time (e.g., a wildfire event), providing a dependable electrical power supply for radio operation and other critical electrical equipment.7
NEW APPROACHES AND THEIR CHALLENGES
Other approaches that modify or work in conjunction with primary sources of energy are a natural part of any discussion of alternative energy. This includes technology and programs that address the following: new power systems (e.g., fuel cells); energy storage (e.g., batteries); power supply enhancements (e.g., concentrated solar power); energy management (e.g., smart grid), and energy conservation (e.g., LEED).
One new type of power system that is satisfying today's energy needs is fuel cell technology. These units create electrical energy through membrane interaction and have no moving components. They often use hydrogen as an energy carrier in a process that leaves no adverse byproducts or residue, and they can use other carbon-based fuels, including bio fuels.
Fuel cells show great promise for the future, and the up-front higher equipment costs can be offset by minimal maintenance and clean and quiet operation. Hydrogen fuel cells have become the power source of choice for certain emergency power supply applications, such as remote telephone communication sites. One recent noteworthy application is a set of 12 fuel cells providing 4. 8 megawatts of power for the new Freedom Tower and related towers at the World Trade Tower site in lower Manhattan.8
Energy storage is not a new concept, as exemplified by Article 480 of the National Electrical Code®9 on battery storage, which first appeared in the 1897 edition. Today, battery systems are being taken to new dimensions, including large battery storage systems that are intended to boost access to distributed alternative energy sources such as wind and solar power supplementing the electrical grid. One example is a new storage cell unit used by a New England utility to coordinate peak energy loads, composed of a collection of 82,000 individual lithium-ion battery cells housed in a shipping container.10
Power supply enhancements are also appearing more often in the built infrastructure. One example is an approach referred to as "concentrated solar power," with large-scale photovoltaic systems that utilize additional features such as moveable panels that follow the sunshine or mirrors to enhance the energy yield of the panels. Some of these systems are not stand-alone facilities, but are appearing on the roof tops of large commercial or mercantile buildings.11
Energy management is another concept that has far-reaching consequences for how electrical power is used in today's world. Perhaps the most noteworthy example of an emerging concept with sweeping implications is the "smart grid" concept. This is a complete revision of how the electrical power supply is managed.12
Instead of a continual one-way feed of electrical power from generation sites to the consumer, smart grid enables bidirectional flows of energy and two-way communication and control capabilities through the use of digital computing and communication technologies within the power delivery infrastructure.13
Energy conservation is an important partner to alternative energy approaches, despite its relative passive nature. This discussion would not be complete without mention of energy conservation approaches that are sweeping the built infrastructure. Fire protection professionals are continually facing new and unusual characteristics, as they balance safety with green building design concepts such as Leadership in Energy and Environmental Design (LEED).14
HORIZONS OF TOMORROW
For all new alternative energy applications, fire protection engineers and other safety professionals are working diligently to maintain expected levels of safety for consumers, emergency responders, operators, maintainers, regulators, and others. The technological advances of tomorrow are making possible a wide spectrum of alternative energy sources. Some emerging technologies such as fuel cells are already showing great advantages, while others such as nano technology for enhanced battery design suggest significant promise for the future. The alternative energy applications of today and tomorrow are making the world a better place, and mitigating any hazards they pose is an important part of assuring their successful implementation.
Casey C. Grant is with the Fire Protection Research Foundation.
- Princeton WordNet, Princeton University, Princeton, NJ, website: wordnet.princeton.edu, accessed: 7 Dec 2011.
- Alternative Energy, website: www.altenergy.org, accessed: 7 Dec 2011.
- "Energy Policy Act of 1992," H.R. 776, 1992.
- Clean Air Act Amendments of 1990, S. 1630, 1990.
- "Solar Hot Water Heating," Solar Evolution, California Solar Center, website: www.californiasolarcenter.org/history_solarthermal.html, accessed: 30 Dec 2009.
- Backstrom, R. and Dini, D., "Firefighter Safety and Photovoltaic Installations Research Project," Underwriters Laboratories, Northbrook, IL, 29 Nov 2011.
- Markley R., "Electricity On The Go," Fire Chief, May 2008, Pgs 64 – 67.
- "Largest Fuel Cell in U. S. Goes Live," Building Safety Journal, International Code Council, Jan-Feb 2009, pg. 35.
- NFPA 70, National Electrical Code, National Fire Protection Association, Quincy, MA, 2011.
- Ailworth, E., "NStar to Test A123's Storage Cell: Would Boost Access to Wind, Solar Energy," Boston Globe, 19 Dec 2011, pg. B-5.
- Grant, C., "Fire Fighter Safety and Emergency Response for Solar Power Systems," Fire Protection Research Foundation, Quincy, MA, May 2010.
- Simonian, L., et al, "Smart Grid and NFPA Electrical Safety Codes and Standards," Fire Protection Research Foundation, Quincy, MA, July 2011.
- "Smart Grid and Standards," Standards Engineering, SES Standards Engineering Society, Jan/Feb 2010, pg. 14.
- Tidwell J. and Murphy J., "Bridging the Gap – Fire Safety and Green Buildings," National Association of State Fire Marshals, August 2010.