Category Archives: energy

Why Bioluminescence?

Heating a house with a wood stove does involve some tedium and even inconvenience. One is adding wood to the stove in the wee hours. A while back, at maybe four or so in the morning, I went down to stoke the stove. The wood at hand had loose bark which I always remove if possible. I removed the bark and to my surprise in the dark house, the bark glowed a pale green.

This is a good example of bioluminescence, a way of producing light without heat. It occurs across the living world – plants, animals, fungi, and bacteria. Light is produced when certain molecules (substrates) react with oxygen with a special catalyst. This releases energy but unlike all other energy-producing reactions, allows the energy to be released in the form of light. The different molecular substrates produce different colors.

In the deep ocean where most bioluminescent organisms live, the predominant color is blue as that is the color that is least absorbed by water. Other colors occur but are much less common. Some organisms don’t produce light themselves but rather keep bioluminescent bacteria in special organs. In the pitch-black darkness of the deep ocean, bioluminescence is used for all sorts of signaling.

Some toxic worms signal their status to avoid predators, other organisms avoid predation by flashing so brightly and colorfully as to dazzle predators. Some will actually lose a glowing appendage to distract. On the other hand, some predators use a bright flash to dazzle prey. Some predators can use their luminescence to act as a flashlight in the dark, illuminating prey.

There are luminescent organisms even at the surface of the oceans. Certain flagellates luminesce, turning the surface of the ocean into a pale green field, often sparkling when disturbed. And then there is sexual signaling.

There are thousands of species of fireflies and most of them are luminescent. Almost all these species use the light to signal species identification for sexual signaling. Often the flash rate or pattern of flashing is unique to a single species. This allows conspecifics to connect for mating.

A really unique firefly species is a sort of black widow or maybe femme fatale. The females of this species mimic the “flash code” of other species of fireflies. When the males of another species are attracted to the false signal, they are promptly eaten. They don’t even get that last hurrah as do the males of some spiders who at least get to have sex before they get their heads bitten off.

Even the fungi may have sex in mind. The wood rot fungus which glows faintly green, the one I observed, is thought to use the glow to attract insects which are useful for spore dispersal – OK not exactly sex, but propagation.

The value of light production is sufficiently important to have arisen evolutionarily over thirty times over hundreds of millions of years.

Dr. Bob Allen is Emeritus Professor of Chemistry, Arkansas Tech University. His website is Bob of the Ozarks,

Hydrogen as an Renewable Fuel

The future of transportation, at least the clean air kind of transportation, will be powered by electricity. Fully electric cars are being manufactured by some companies most notably Tesla and most manufacturers have plans for them. Even big trucks such as semis are being developed to run on electric motors. Plug-in hybrids and simple hybrids utilize a combination of electric motors and Internal Combustion Engines (ICE) for greater fuel efficiency than straight ICE-powered vehicles.

Vehicles that use electricity for at least part of their motive power use batteries for onboard energy storage. These batteries can be charged from the grid for plug-in hybrids. Hybrids such as the Toyota Prius are charged on the fly by regeneration from braking or alternatively by charging from the ICE.

Under certain circumstances such as rail traffic, the electricity can be provided through the tracks or overhead wires. Depending on the country most to all rail traffic in Europe is powered by motors charged by overhead electric lines.

An as yet exploited alternative to batteries or electric lines are fuel cells powered by hydrogen. A fuel cell is a device which uses hydrogen as the fuel to be converted directly to electricity. The only product of the process is water.

Hydrogen as a fuel has several advantages. As noted it is “clean burning” the only product being water. Important for transportation is its very high energy density. For a given weight Hydrogen has about three times as much energy as gasoline and over 100 times as much as that stored in a battery used in electric vehicles.

Under normal conditions, what chemists call Standard Temperature and Pressure, Hydrogen is a gas but it can be pressurized to decrease its volume. The biggest drawback to Hydrogen as compared say to a fossil fuel is that it can’t be pulled from the air or mined from the ground, it has to be created. Currently, the cheapest way is to strip the Hydrogen from natural gas. Alternately, it can be made from water via a process called electrolysis.

If the energy to make the electricity needed is from wind or solar, it is a way of making a storable form of renewable fuel. And that is a really big area of research. Of course one can always just use solar/wind-generated electrical energy to do electrolysis, but there are inefficiencies.

Two areas of research are microbial biomass conversion and direct photocatalytic production. Microbial production of Hydrogen comes from engineered bacteria that produce Hydrogen when fed. If the feed is something such as fructose made from corn, then the process is renewable.

Likely the best method is the latter, photocatalytic production. Some materials, Titanium Dioxide is one example, when placed in water and exposed to sunlight cleave the water releasing Hydrogen and Oxygen. The problem is low efficiency. Intense research is examining a welter of more exotic materials that are of much greater efficiency.

Currently, Toyota is the only manufacturer selling a Hydrogen fuel cell vehicle. In the United States, they are for sale only in California and Hawaii, and even in these locations, Hydrogen fueling facilities are few and far between.

Dr. Bob Allen is Emeritus Professor of Chemistry, Arkansas Tech University.

Scalability in Energy Production.

Scalability is the capacity to expand production as the need for additional power comes to the fore. A nuclear power plant can take years from the time of initial planning, permitting, and construction, whereas installation of solar panels for a home array will take only a couple of days. The material and labor costs during the construction or installation phase raise the cost of the power source over the cost to fuel and operate the facility once completed.

For necessarily large projects like nuclear or hydro-power facilities, long lead times are needed to bring power on line. This means that planning and construction must begin long before the power is available. This has considerable monetary cost because money is spent year after year before any money comes in from the sale of the power after completion.

An unpredictable risk inherent in the long term, big projects is that conditions may change. A steep drop in the economy during the recent “great recession” resulted in decreases in demand for energy world wide. Changes in technology, particularly with power sources which are more scalable may make a large project obsolete. Natural gas turbine technology is quite scalable. Turbines designed for jet aircraft can be used to generate electricity. The advent of directional drilling and fracking has greatly increased the availability and lowered the cost of natural gas which fuels scalable gas turbine facilities. Planning and construction of large scale coal plants are being canceled left and right.

Our economy is slowly recovering from the recession and new power sources are needed. Scalable power supplies are rapidly replacing large projects because they can reliably deliver power when and where it is needed and at a lower cost.

Solar power is booming across the country. Solar PV is growing 17 times as fast as the economy as a whole. This is due in large part to its scalability. If you need a little power, use just a few panels, such as what be need to charge the batteries on a remote cabin or an RV. To power the average home requires about 20 or 30 panels (10 kilowatt system which can produces 1100 kWh per month.)

For utility scale solar the numbers can get quite large. A one megawatt facility in Benton AR just went online. It employs 3,840 panels on a 5 acre site. The largest planned in Arkansas is an 81 MW, 500 acre facility with 350,000 panels. The country’s largest array not surprisingly is in California. At 550 MW, the array of over 2 million panels will power close to 100 million homes.

Wind is similarly scalable except at the lowest end of the spectrum. Modern wind turbines for utility scale facilities are 2 MW, however 8 MW turbines are being used in offshore locations. For perspective an average nuclear reactor is 1000 MW. Wind farms in the midwest vary in size but average around 200 turbines. A wind farm of this size could cover 50 square miles, but the actual footprint is minuscule as the land within the farm can still be used for forage/pasture.

Human Energy, Embodied Energy

Humans, as just about all living thing, have a capacity to do work. By subtracting the energy we need for basal metabolism from total caloric intake we get a measure of useful work. For an average American, we do about 500-1000 kilocalories of work daily. Converted to kilowatt-hours (kWh) it’s only 1.2 kWh.

We consume vast amounts of additional energy in the form of electricity and gasoline to name just two, and the indirect energy embodied in the goods and services we use in modern society. If we add it all up and convert it to a single unit, it comes to 220 kWh per day. It is as if we all employ over 200 slaves a day! How in the world did we get here?

One place to begin is with human control of fire. There is clear evidence of the control of fire 200 to 300 thousand years ago, which roughly corresponds with modern humans, Homo sapiens. However there is growing evidence of the use of fire goes as far back as a million years ago. Not only did fire provide warmth and protection but also increased nutrition.

Only a slight step up from burning wood was the use of charcoal. This was important for the advancement of the various metal ages. Copper and Tin were ores easily smelted using charcoal which provided both an energy source and a chemical reactant for making metals. The bronze age, bronze being made principally from Copper and Tin, dates to the dawn of civilization – about 6000 BCE, 8000 years ago. This begins the use of embodied energy, rather than direct energy use.

The next step was a giant one, the identification of fossil fuels as energy sources. The demarcation of modern life begins with the industrial revolution around 18th to 19th centuries. This is the age of coal and iron and mechanization. The steam engine powered by coal not only revolutionized manufacturing but also transportation via steam trains and ships.

The beginning of the age of oil is usually connected to Edwin Drake’s oil well near Titusville, PA. Crude oil and its refined products rapidly displaced other energy sources because of convenience. Our success in World War II was due in large part to our exploitation of fossil fuels for manufacturing and transportation.

World War II also ushered in the atomic age, first with bombs, then “atoms for peace.” The first civilian nuclear reactor in the US (the first in the world was in the Soviet Union) was in Shippingport, PA in 1958.

As our consumption of crude oil continued to increase, by 1969 our ability to produce oil peaked. Shortly thereafter the Organization of Petroleum States formed, began an embargo, and caused the US to realize that in terms of energy we are not be the masters of our fate.

Loss of control of the oil market, coupled with the increasing recognition of the harmful effects of the burning of fossil fuels ushered in the beginning of renewable, or better described sustainable energy sources, notably wind and solar.