75 Green Businesses You Can Start to Make Money and Make a Difference. Glenn Croston
converting it to other forms. Plants take energy from the sun and convert it to chemical energy found in sugars, lipids, and proteins. Animals take the chemical energy of plants and convert it again to other forms like heat, sugars, and movement to survive. Microbes are exceedingly skilled at the energy game. These powerful microscopic critters do a variety of tricks with energy that “more evolved” organisms, such as humans, can’t. This allows microbes to live in just about every corner of the earth, and to produce energy from the tons of organic material we throw in dumps, burn in agricultural fields, wash into rivers, and flush down toilets. Instead of leading to poisoned rivers, overflowing landfills, and expensive waste-water treatment plants, this wasted chemical energy can be converted into useful energy.
Some of the energy in waste is captured by burning it and generating electricity using turbines. Another way to capture the wasted energy is to convert it to some other form that can be burned, just as microbes digest cow manure to produce methane and generate electricity (see Opportunity 72). Incineration is not always the answer though; in the case of solid waste from sewage, burning in incinerators is often out of the question. While a fire releases energy explosively and loses a lot of energy as heat into the surroundings, microbial fuel cells provide clean and efficient power generation without the pollution produced by incinerating waste. Microbial fuel cells produce energy directly by pushing electrons through a wire while eating waste.
Bacteria called “iron-eaters” eat organic compounds like acetic acid, pushing electrons to create an electrical current, generating power. Derek Lovley at the University of Massachusetts at Amherst has produced microbial fuel cells using iron-eating bacteria that are almost 80 percent efficient in capturing electrons to produce power, far more efficient than previous efforts to build microbial fuel cells or burning waste. Dr. Bruce Logan at Penn State has coaxed more garden-variety microbes into producing energy from wastewater and is working to demonstrate the process at larger scales. These academic breakthroughs may pave the way for businesses developing microbial fuel cells and applying them as a new form of renewable energy.
INFORMATION RESOURCE
For more about how microbial fuel cells work, see the websites of Dr. Bruce Logan (engr.psu.edu/ce/enve/logan.htm) and Dr. Derek Lovley (bio.umass.edu/micro/faculty/lovley.html).
One way to use microbial fuel cells is to generate electricity at wastewater treatment plants. We produce a lot of wastewater, and in the United States, getting rid of it consumes about $25 billion per year and 1.5 percent of our electricity (Mechanical Engineering magazine, 2004). The material contained in wastewater holds a lot of energy; it just needs to be unlocked and harvested safely. Waste treatment takes the organic matter in sewage and aerates, filters, and settles it to degrade organic material and remove dangerous microbes. Nothing useful is done with the energy in the waste. The process leaves behind a solid material called sludge that contains a lot of chemical energy but can be difficult to dispose of. One solution for sludge is to incinerate it, but sludge often contains pollutants such as heavy metals that can be released by burning. Microbial fuel cells could greatly improve the efficiency of water treatment, particularly where it is already costly.
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What other devices are there where users would not want to change batteries ? These are candidates to use fuel cells instead of batteries for power. They will still need some type of food for the microbes, but otherwise microbial fuel cells could have a wide range of applications.
The challenge of harnessing microbes to produce power for humans is often getting the microbes to convert energy into a form we can use, such as electricity. The next trick is making this process commercially viable. To build a microbe-power business, start by understanding the current state of research. Ask academic experts and their tech transfer offices at universities if intellectual property is available to license. Building electrodes with greater surface area is one field of practical research. According to Dr. Logan, the key challenge for commercialization of microbial fuel cells is “making it economical in terms of cost of materials and scaling it up.”
One niche application is for the creation of environmental sensors. Sediments in oceans, rivers, and lakes contain organic material that can fuel a microbial fuel cell. Dr. Leonard Tender at the Naval Research Laboratory has developed a Benthic Unattended Generator (BUG) that gets its power from a microbial fuel cell to gather and report data on water and air conditions at sea. As the technology continues to develop, eco-entrepreneurs may use microbial fuel cells to build self-powered municipal water-treatment systems, home septic tanks, or even self-powered portable toilets.
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Microbial fuel cells also can produce hydrogen from wastewater, helping to fuel the hydrogen economy from wastewater in the future (Bruce Logan, Penn State).
For eco-entrepreneurs who are not afraid to get their hands dirty and are ready for a challenge, microbial fuel cells might pay off. New strains of microbes, conditions for fuel cells, material for electrodes, electrode shapes, and food for microbes are areas where ongoing research may open new doors and applications. When it comes to the amazing microbes, anything is possible.
Summarizing microbial fuel cell opportunities:
OPPORTUNITY 8 Fuel Cell Backup Power
| The Market Need | Replace noisy, polluting diesel generators with better solutions for emergencies and remote locations |
| The Mission | Provide fuel cells for backup power, emergency power, and mobile power |
| Knowledge to Start | Business (to sell and distribute) |
| Capital Required | $$ |
| Timing to Start | Months to years |
| Special Challenges | Finding a product to sell and distribute, and targeting the right market |
Having a constant supply of electricity may once have been a luxury, but now it is an essential part of life. When our electricity fails, the consequences range from an inconvenience to life-threatening. When the power fails, it can mean lost work on the computer, lost food in the refrigerator, or a dangerous loss of power for medical equipment. Electricity has proven unreliable when weather, fires, and equipment failures strain an aging power-distribution grid. With the U.S. grid in desperate need of investment and power demand threatening to outstrip supply, the power supply will remain precarious for some time to come. Eco-entrepreneurs are addressing this need by providing clean backup power from fuel cells.
To avoid power interruption, businesses, hospitals, and many others have invested in backup generators. According to ABI Research, the market for generators in 2007 was more than $6 billion worldwide. Anxiety about an uncertain