Tag Archives: energy

Electric Vehicles – Nuts and Bolts

One of the biggest advantages of electric cars is that there are fewer of those nuts and bolts. Also no oil, coolants, belts, transmissions et al. The fewer moving parts in the drive train, the longer it will last, other things being equal. Although electric cars are now more costly on the front end, the much lower maintenance and fuel cost result in lower cost over the long run.

The cost to own and operate a vehicle is the ultimate determinant for a lot of folks, but after that are a few other things about electric cars, one being fueling and the storage of the fuel. We’re talking about charging batteries. The unit of energy for electric cars is kiloWatt-hour (kWhr.) A fully charged battery pack will hold a certain number of kWhrs, (a Chevy Bolt battery pack will hold 60 kWhr) the more the battery pack will hold, the farther you can travel, just like a bigger fuel tank gets you farther.

How efficient the electric propulsion is in miles per kwhr is important A small to medium electric sedan can be expected to get about four miles per kWhr with all the caveats which influence an internal combustion engine (ICE.) Generally, the faster you drive, the poorer is your mileage. Colder weather and strong headwinds affect electric and ICE-powered cars alike. The United States EPA has made it easier to compare the efficiency of gas and electric cars. For electric vehicles, the EPA provides a number, miles per gallon equivalent (MPGe) which allows a direct fuel efficiency comparison. For mid-sized electric sedans, the mileage is greater than100+ MPGe.

With a mileage that is three to four times better for an electric vehicle over an ICE, it will cost you one-third to one-quarter of the cost of buying gasoline for a given distance. One of the few drawbacks of electric cars is charging time, which varies depending on the charging technology.
The simplest way to charge an electric car is to plug it into a wall outlet. This will charge slowly because 110-volt outlets run at a minimal current. To fully charge an average electric vehicle will take a day or more at a wall outlet. For topping off a battery or for short errands around town this is sufficient. For longer trips, it is better to install a 220-watt charge station. This is referred to as a level II charger. These will fully charge a battery overnight.

If you’re ready for that two-week vacation with the family you will need to find level III chargers, just like you need to find gas stations along the way. Now it gets a little messier. Different vehicles have different connector plugs so you have to be sure you find the right kind of charger station. A small to mid-sized electric sedan can fully recharge in about one half an hour. A road trip in an electric vehicle will necessitate stopping every three to four hours for one half an hour. Enough time to stretch your legs, go to the restroom and get a bag of chips and a cold drink. As battery technology continues to improve, the distance you can go will increase, and the charging time decrease. Bon Voyage.

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

A Natural Reaction

Uranium is, of course, the stuff of nuclear reactors and atomic weapons, but it is also part of an intriguing detective story from 1972 that traces back to events two billion years ago – actually 4.5 billion years but at that age who’s counting.

First a little background. For either nuclear reactors or bombs, Uranium 235 is required. This isotope of Uranium has fewer neutrons in the nucleus and is present in small concentrations with U238, the most common isotope. U235 with a natural concentration of 0.72 %, must be concentrated further to make a fissile material that is used in reactors and weapons.

In the early seventies, there was something of a panic in France. France, then as now provides the lion’s share of their electricity from nuclear reactors. At the time France was buying Uranium ore called yellow cake from a mining region in the Oklo River basin in Gabon, Africa. Assays of some shipments showed that the ore was unnaturally low in U235, sometimes by as much as half the expected concentration.

During this period there was much civil unrest as the continent slowly emerged from under the yoke of colonialism. It was feared that Uranium was being stolen by a local tribe with the intention of making a crude bomb. It turns out that the problem was a rather unnatural event in nature. When scientists looked at an analysis of the shipments low in U235 they found several unnatural elements such as Americium, Curium, and Polonium.

These so-called transuranic elements were not known to exist in nature until this discovery. The only place they had been observed was as part of the waste from nuclear reactions, both controlled reactors and bombs. The French had discovered an extremely rare event, a natural nuclear reactor.

When the U235 atoms draw too close together a chain reaction occurs which produces heat. That heat is used to produce steam in nuclear reactors. In the process, the U235 reacts to turn in to other elements. Exactly the same process occurred in the Oklo River basin.

Over two billion years ago there was scant free Oxygen in the air, then along came cyanobacteria. Gradually the atmosphere changed and many minerals reacted with Oxygen. All the rusty looking soil across the planet is due to Iron Oxide which formed during this period.

In the case of Uranium, it became more water-soluble as it oxidized. In locations with rich Uranium deposits such as the Oklo River basin, this allowed for the dissolved Uranium to accumulate in shallow lakes. Over time some of these lakes became isolated and as the lakes evaporated the Uranium was concentrated. Another bacteria capable of taking the Oxygen away from the Uranium Oxide reduced the solubility even further.

When the Uranium in these pools reached critical mass – the concentration necessary for a chain reaction – the U235 fissioned producing heat and forming the transuranic elements. As the reactions proceeded the U235 was depleted. Altogether sixteen different sites in the river basin have been found to have undergone fission reactions. To date this is the only known place on earth where a natural fission reaction has occurred.

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

Energy Storage Efficiency

There are those who constantly dismiss wind and especially solar as impractical energy sources because it is not available all the time, hence standby power must be available – fair enough. Right now Unit One of Arkansas Nuclear One is offline for refueling.

So is anybody sitting in the dark for a month or two? Of course not. Must there be another nuclear reactor standing idle waiting for Unit One to go down for refueling? Again the answer is no. There is sufficient excess capacity in our electrical grid to make up the difference in electrical energy needs during the outage. The same is true today for our intermittent energy sources, wind and solar. It is estimated that no additional backup will be needed until we reach about thirty percent contribution of these renewable sources to our total electric production.

Right now wind turbines to our west and the solar panels at my home use the grid as storage, just like Unit One. When the wind isn’t blowing, the sun isn’t shining, or Unit one is offline to refuel, the other power sources in the grid make up the shortfall. Electrical energy transmission and storage are hot research topics in science and technology. Numerous ways exist already for grid-scale energy storage, the ongoing research is to find ways to store energy efficiently and affordably.

One option being explored by as Swiss company is a cuckoo clock writ large. Excess energy is used to raise concrete blocks up, just like the weights on a clock. To recover the stored energy simply allow the weight to go down, turning a generator as they come down. This type of energy storage is not very efficient, maybe sixty to seventy percent, but is inexpensive.

At the other end of the spectrum is a high-cost, high-efficiency strategy such as a rechargeable Lithium-ion battery. The efficiency here is about ninety percent. Although expensive, Lithium-ion batteries are quite lightweight so they have value to power portable devices, from hearing aids to electric cars.

One energy storage medium that most don’t recognize as such is Hydrogen. Hydrogen gas is very energy-dense, meaning a small amount of it will store a lot of energy. Hydrogen can be generated by electrolysis of water. The hydrogen can be stored until energy is needed, then the hydrogen can be burned to make steam to turn a turbine to generate electricity. But, burning anything to produce heat to turn a turbine is a quite inefficient process. Because of the laws of thermodynamics, you can only get back about a third of the energy put in.

Better than burning to make heat is another technology known as a fuel cell. Fuel cells convert Hydrogen back to water without as much waste heat. Hydrogen generation via electrolysis, then conversion back to electricity has a “round-trip” efficiency of about fifty percent.

The science and technology of grid-scale electrical energy storage will mature as we expand our reliance on wind and solar, ultimately eliminating the use of fossil fuels.

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

Exxon valdez cleanup

Trump, the Environment, and the Cabinet

It would appear that president-elect Trump thinks our air and our water are too clean and If he is successful we are likely to have less of both (and there is no reason to assume he won’t be successful due to the republican majorities in both houses of congress.)

Oddly, in 2009 he signed a letter along with numerous business leaders to President Obama encouraging him act. “”We support your effort to ensure meaningful and effective measures to control climate change, an immediate challenge facing the United States and the world today” … and further “If we fail to act now, it is scientifically irrefutable that there will be catastrophic and irreversible consequences for humanity and our planet.”

Now his pronouncements are just the opposite. In 2010 he said that Al Gore should have his Nobel peace prize revoked because he decided that global warming was a hoax. His evidence du jour was the fact that it was winter and snowing. Later still he expanded on the hoax idea claiming that not only were the world’s scientists conspiring to promote a hoax but apparently doing so at the bidding of the Chinese who invented the hoax in the first place.

So when Trump takes office in January which one will show up ? Will it be the Trump of “catastrophic and irreversible consequences for humanity …” or the more contemporary Trump of 2015: “it’s a hoax, it’s a hoax. I mean, it’s a money-making industry, okay? It’s a hoax.” Some how it is not surprising that Trump sees money as the only motivation.

Based on a few cabinet nominations it looks like the recent Trump will show. Scott Pruitt, nominee to head the Environmental Protection Agency is currently the Attorney General of the state of Oklahoma, the politics of which are dominated by the oil and gas industry. In this position he has sued the EPA numerous times to block the EPA from enforcing regulations aimed to protect our air and water. If the Senate approves the nomination, it will mark a sea change at EPA. Every previous administrator at EPA has worked to protect the environment and relied on sound science.

Another critical cabinet position is the Secretary of Energy, currently headed by a theoretical physicist with a PhD, Ernest Moniz. The Energy Department oversees not only our overall energy policy but also controls our nuclear armaments. Trump’s pick is Rick Perry former Governor of Texas and a friend of the fossil fuel industry. In 2008 Perry ran for president. One of his planks was the elimination of the Energy Department. With no small irony, during a debate he was asked to name the departments he intended to eliminate. He only had to remember the names of three departments, but he remembered only two – Energy was not one of them.

Although the mission of the state department is only tangentially related to the environment, Trump’s selection speaks volumes. Nominated for Secretary of State is none other than the CEO of Exxon-Mobile, the world’s largest player in the fossil fuel industry. Rex Tillerson as head of Exxon-Mobile had planned a 500 billion dollar deal with Russia to drill for oil and gas in the Arctic. When Russia annexed Crimea and was implicated in shooting down a commercial airliner over Ukraine, sanctions from the US and other western powers made the artic drilling deal null and void. Mr. Tillerson noted at a news conference in 2015 that he looked forward to lifting the sanctions on Russia. Drill baby Drill.

Crude Movements

It seems that oil pipelines are in the news of late. Some of the new pipelines are to deal with the expanded production of crude oil here in the US. New and better technology – hydraulic fracturing (fracking) and directional drilling have resulted in the need for transportation of that oil, pipelines generally being the cheapest.

We produce about 10 million barrels of crude oil per day and import another 10 million barrels from sources all over the world. Most of this is turned into fuels such as gasoline and diesel fuel and only a pittance for non-fuel petrochemicals.

But are pipelines the best way to go? Other methods to move the crude oil from where it is produced to where it is refined include barges, rail cars and tank trucks. What is the best way to do it? It depends entirely on what metric you use to measure “best.”

If you simply want to compare the least oil spilled when normalized for amount of total oil transported per distance moved (ton/mile) the ranking is barges and tankers are better than rail is better than pipeline is better than truck.

If your metric is human deaths and property destruction we get a different rank: barge is better than pipeline is better than rail is better than truck. How about environmental damage? Because aquatic environments are more sensitive the ordering becomes: Rail is better than truck is better than pipeline is better than barge.

Oh but it gets more confusing, because so much of the crude oil moves by pipeline, about 70%. Another 23% by barge and tanker, trucking 4% and rail transport a mere 3%.

If a decision were made to go to more trucking for example the change for the better (or worse) would not necessarily be linear. More trucking would mean more congestion, hence an increased risk of untoward events even after adjusting for total oil moved.

There is already some evidence of the non-linearity of change. From 1975 to 2012 trains were much shorter and had very few spills, but the recent oil boom means a higher proportion of oil moving by train. Because of longer trains and more frequent crashes, more oil was spilled in 2013 alone than the previous 37 years.

It is just not a simple “what is the best.” This conundrum is reminiscent of a senate hearing back in the 1970s. Ed Muskie was conducting a hearing as to the risks of the supersonic Concorde flying over the United States. The committee’s chief scientist said, “Senator, we’re ready to testify,” and Muskie responded, “Okay, tell me what the answer is. Is this going to be a danger?” The scientist responded “I’ve got these papers here that definitely tell us this is going to be a danger.” Muskie was ready to conclude right there, but then the NAS scientist interjected, “On the other hand, I have another set of papers over here that says these papers aren’t good enough to know the answer.” Incredulous, the senator looked up and yelled, “Will somebody find me a one-handed scientist?!”

A one-handed scientist may produce a simple answer, but it won’t necessarily be the only or best answer.

Go Solar

The amount of solar energy available to the United States is overwhelming. With today’s Photovoltaic technology, 16 per cent efficient PV panels, the total energy needs of the country could be met using a land area of only 8,000 square miles. This is an incredibly small area compared to the 3.8 million square miles of total land area. All the solar panels we need to power the country could fit in a fraction of Elko County in Northeast Nevada.

Just imagine, miners don’t need to die underground to extract coal. Mountain tops don’t need to be blown off and pushed into valleys to get at a coal seam. We wouldn’t need to worry about whether fracking wastes pollute our ground water, or bust up the foundations of homes to access natural gas. We don’t need parking lots full of high level radioactive waste from nuclear power plants. Yes, you read that right. Our only plan for the storage of high level radioactive wastes, hot for tens of thousands of years, is to store the waste in concrete containers around the sites of nuclear plants.

The health of the public would be improved and incidentally the cost of healthcare lowered as we no longer would have have all the untoward things in the air that cause problems. Not burning any fossil fuels means less lung irritants such as fine particulates. Less heavy metals that cause nerve damage, less acid rain, less ozone, and the list goes on and on.

Rather than produce all the energy in a fraction of one county in Nevada, we could spread it out to the individual states. The US uses a total of about 4 trillion kWh per year. Closer to home, Arkansas uses about 50 billion kWh per year. To meet that need we would only use about 100 square miles, less than a tenth of the area of Arkansas County in the southeast part of the state. Or let’s make each county generate their share. For Pope County we need a scant 2 square miles out of 831. It’s easy to see that we have plenty of free, sustainable sunlight and the land foot print needed is not even an issue. We will also need to upgrade our transmission network, but still that’s doable. The real fly in the ointment is storage.

The aforementioned calculations of land area needed are for full power, 24/7 year around, assuming we have storage for when the sun doesn’t shine due to time of day, season or weather. This a problem but not an insurmountable one. Elon Musk, the manufacturer of the Tesla electric car, and Space X reusable rockets is building a huge battery factory in Sparks, Nevada. The battery factory will occupy a building covering an area equal to 95 football fields.

The factory will be powered exclusively by solar electric power, with energy to spare. The batteries built in this factory are lithium based and are intended for his fleet of electric cars, but it shows that really large scale production of all aspects of sustainable energy are not just something in the distant future but are close at hand.

Fracking Yeas and Nays

Fracking, short for hydraulic fracturing, is a process which has been around for over 60 years but because of recent technological changes is being used to increase production of oil and gas. Basically a fluid is pumped underground under high pressure causing the substrate to fracture which allows oil and gas to move more readily through the fissures created into the well and up to the surface.

The historical precedent goes back to the post civil war era. Civil war veteran Col Roberts received a patent for a method to increase production in oil wells that involved dropping a nitroglycerin filled “torpedo” down the well shaft. The explosion would fracture the formation, increasing oil production.

Hydraulic fracturing began about 1950. The recent fracking boom is the result of a combination of advances to the technology including directional drilling and the use of “proppants” like sand and glass beads which prop open the fractures. The technique was pioneered here in the US but its use is rapidly expanding around the world.

There is no question that it is a hot button issue. Some claim that it is a useful, even necessary way to produce fuels for a growing economy. Others suggest the the environmental problems associated with the technique are so untoward as to require banning its use.

Natural gas, regardless of its source, has been called the Prince of Fuels. Among fossil fuels it is by far and away the cleanest burning. It has essentially none of the noxious impurities like sulfur and heavy metals that occur in both coal and oil. It also has a considerable advantage in that it produces more energy for the amount of carbon dioxide produced. Older coal fired power plants have been closing across the country, due in part to it replacement by natural gas plants. Natural gas could even replace liquid fuels for transportation as compressed natural gas (CNG) or by catalytic conversion to a liquid fuel.

Natural gas can be burned in turbines to generate electricity. Gas turbines are ideal as a source of rapidly dispatchable energy that combines well with intermittent renewable energy sources such as wind and solar panels. If the wind blows hard, you idle the turbines, light wind, power up just a few, no wind, turn ’em all on. Over half the natural gas produced in the US comes from fracking.

There are however serious downsides. Fracturing requires a toxic witches brew of hydraulic fluids and some suggest that these pollutants in the fluids have found their way into groundwater. Although it is not hard to imagine how this could happen, the evidence of it actually happening is scant. A more clearly defined problem is the cluster of shallow earthquakes that correlate well with spent fracking fluid reinjection sites. Once the fluid has been used it is disposed of by permanent injection into wells. This fluid under pressure lubricates the subterranean rock layers allowing them to move, hence earthquakes.

Natural gas, essentially methane, is itself a potent contributor to global warming. A final negative is the growing evidence that fugitive emissions from gas production and transmission facilities is a serious contributor to global warming.

These negatives are not insurmountable. Better well casing and location limitations can minimize the risk of ground water pollution. Reprocessing of used fluids, rather than injection will end the earthquake issue, and simply “tightening up” the production and transmission facilities will lessen the fugitive emissions.

Cars and Cold Weather

Anyone who pays even passing attention to their fuel economy know that regardless of the vehicle driven, colder weather means poorer performance for a myriad of reasons. Important to all vehicles is inefficiency due to rolling resistance and wind resistance. Electric cars have additional inefficiencies due to battery issues.

In cold weather lubricants, which keep parts which move with respect to each other moving, are more viscous and therefore more resistant to movement causing drag. Another source of resistance to motion comes from the lower tire pressure in cold weather. Students in introductory chemistry classes learn Guy-Lussac’s Law: Pressure is directly proportional to temperature. Lower temperatures mean lower tire pressures.

Both friction due to viscous lubricants and lower tire pressure are overcome because both cause friction and friction generates heat. Depending on how cold it is, and how long the vehicle is driven, parts warm up lowering lubricant viscosity and tires gain pressure as they heat up.

Even the air itself conspires in cold weather. Vehicle designers pay careful attention to “slipperiness,” as wind resistance is a big factor especially for a fast moving car or truck. Wind resistance is a function of the density of air and air density is inversely proportional to temperature. Colder air is denser air and provides more resistance.

Internal combustion engines (ICEs) have to be tuned to run rich to get started in cold weather. This means that more fuel is used to get the engine started and up to operating temperature. Additionally, in the winter people tend to start up their engines to warm up the interior of the car before it even hits the road.

Hybrids, plug-in hybrids, and pure electric vehicles suffer an additional problem, because they all are powered to some degree by a battery and batteries in cold weather are a problem. A hybrid electric vehicle like a Toyota Prius has a traditional ICE connected to the drive wheels, with an electric motor which supplements the ICE. Plug-in hybrids are a little different. They have an electric drive train with an ICE used exclusively as a generator to charge the battery when it is discharged. Of course all electric vehicles have only the electric motor and a comparatively large battery to extend the range on a charge.

Two factors contribute to cold weather reduced range in battery powered cars. The colder a battery is the less charge in will accept, thus lowering the vehicles range until the next charge. A factor called internal resistance increases as the temperature decreases. This means you don’t have as much energy stored from the outset. Further reducing range is the process which converts chemical to electrical energy. The distance you can travel on a unit of energy is lowered in colder weather.

Electric cars have reduced range on a given charge in cold weather, but overall are still cheaper to operate than an ICE vehicle. Basically the cost of electricity for a given amount of travel is much less than the cost of gasoline for an ICE vehicle, even at today’s greatly reduced cost for gas.

Transportation Resistance

From Galileo to Elon

Over 400 years ago as the story goes, circa 1590, Galileo performed a scientific experiment which has been reproduced in schools across the planet to this day. Galileo went to the iconic leaning tower of Piza and dropped two balls, one larger and heavy than the other. As everyone knows, they hit the ground about the same time. This disproved Aristotle’s hypothesis that heavier objects fall faster.

What both Galileo and Aristotle were not considering was an aspect of fluid dynamics – air resistance. Basically air is a fluid and it gets in the way of movement. Anyone who rides a bike or paddles a canoe knows it’s a lot harder with the wind at your face; that is, greater air (or wind) resistance. Even if the air is standing still, it still gets in the way and slows things down. The faster you go, the more important the wind resistance becomes.

A bicyclist can make about 15 to 20 mph without too much difficulty but more than that is a problem due to drag. Get rid of the drag and the sky is the limit. Cyclists have attained well over 100 mph riding behind vehicles outfitted with a fairing to shield the cyclist from wind resistance.

In years past when fuel costs were low, the extra energy expended to overcome wind resistance was not important in motorized vehicles. It is today and will continue to become more important as fuel costs rise. Nowhere is wind resistance, that is aerodynamic drag, more important than in the trucking industry.

The first effort in the industry was the addition of fairings over the cabs of 18-wheelers which resulted in a 15% increase in fuel efficiency. A more recent innovation is the addition of side skirts on each side and between the wheels of big rigs, which have been shown to improve fuel efficiency by 5 to 15 percent depending on design. Finally “trailer tails” are being added to extend the saving another 5%. All together this add up to over 30% fuel savings, with payback times of a about a year for fleet vehicles.

Small steps to save fuel or increase speed result from reducing drag, but what if you could completely eliminate drag by eliminating the air itself? Listen up. Elon Musk is the billionaire savant who produces the wildly successful Tesla electric car. He also pioneered private industry space flight with his SpaceX company, which is regularly delivering supplies to the International Space Station orbiting above earth.

Mr. Musk has proposed building giant evacuated tubes into which transportation vehicles could attain speeds in excess of a thousand mph. These tubes would work just like the little canisters that deliver your checks and cash back and forth from the bank window to the remote drive-up station. The only difference is that people or bulk goods would go in the canisters, and travel thousands of miles at thousands of miles per hour. He has suggested that eventually an underground transportation network could transport people from New York to Los Angles in 45 minutes! That requires a speed of about 4,000 mph.

Why Electric Cars?

At the dawn of the automotive age electric cars were, in proportion, more numerous than today. With cheap gasoline and the much greater range the internal combustion engine (ICE) came to dominate the market and continues to do so to this day.

The tide is beginning to turn, slowly, but it is turning. First fuel is not so cheap anymore. In 1970 the price of a barrel of oil was about 3 dollars. This was the last time the US was a net exporter of oil and therefore had some control of the price. Adjusted for inflation that would be about 18 dollars currently. Even at the recently depressed price of around 50 dollars a barrel, it is several times more expensive than in 1970. A car getting 25 miles per gallon will cost the driver of an ICE powered car about 2.50 $ to cover 25 miles.

How does that compare with an electric powered vehicle? Modern vehicles running on electricity, whether they are hybrids, plug-in hybrids, or pure electric get around 4 miles per kiloWatt-hour (kWh). Locally electricity costs are around 9 cents a kWh. To cover that same 25 miles in this comparison means that the fuel cost for an electric car is 75 cents, less than a third the cost for gasoline.

An important feature of electric cars is their ability to recapture some of the energy consumed after accelerating up to speed – when you take your foot off the accelerator in an electric car the motor acts like a generator sending power back to the battery. It’s immensely important in stop and go traffic. This is a principle reason why hybrid cars such as the Prius get such good mileage, even thought they have only a small supplemental electric motor/battery for an otherwise gas powered car.

Gasoline engines have hundreds of moving parts. The parts need lubrication, and cooling and exhausting, and on and on. It is interesting to note that Forbes magazine has described the maintenance shop at new car dealerships as the principle profit center. You may negotiate a lower price for a new car but I doubt any negotiating room to lower the cost for labor and parts in the shop.

For an electric engine there is essentially one moving part, the rotor. No significant lubricants are needed, no coolants to maintain, no exhaust system, you don’t even need a transmission except to go forwards or backwards. Hence maintenance of an an electric car is significantly cheaper than ICE powered cars.

There are a couple of current drawbacks. Modern electric cars are produced as yet in small numbers and therefore don’t benefit from economies of scale. As they become more popular costs will fall. The biggest limiter right now is range and charging time. The high end Tesla with a 120 kWh battery has a range of over 250 miles. The charging time with one of their “superchargers” is about an hour.

The Chevrolet Volt, at half the price of the Tesla model S, has a 40 mile range on electric but the range is extended by an on board ICE that serves only to charge the battery on the fly.