Tag Archives: sustainable energy

wind turbine

Size Matters/Wind Turbines

Utilization of the wind for motive power has a long and rich history. Wind-powered sailing vessels were known to ply the Nile river somewhere between 3 and 5 thousand years before the common era (BCE.) Although there is no direct evidence, it is quite possible that sailing craft could have been employed 50 thousand years ago to populate Southeast Asia and Australia.

Stationary power production in the form of lifting water has been dated to a few centuries BCE. Similarly, the wind was used for motive power to grind grain. The use of wind turbines in the Netherlands is legendary. By the 14th century CE, the Dutch were making extensive use of wind turbines to pump water out of the Rhine river basin to recover and maintain dry land. There is a reason this part of Europe is referred to as the “Low Countries.”

The history of wind for the generation of electrical energy is of course much younger. In 1877 Professor James Blythe in Glasgow, Scotland erected a 10-meter tall cloth-sailed wind turbine connected to batteries to light his cottage. Small scale isolated wind-powered electrical production has been in use around the world, including early twentieth-century Midwestern United States. Centralized power delivered via rural electrification in the 30s replaced virtually all small systems.

The modern era of electrical power production began in the 70s following the formation of the Organization of Oil Exporting Countries (OPEC) and subsequent oil price shocks and embargoes. The price of crude oil skyrocketed and shortages of gasoline forced rationing. Later years saw the federal government subsidize wind power with grants and production credits. In 1990 less than one percent of total electrical energy in the United States came from wind. Currently is over seven percent.

The real change in wind power is the size of the turbines themselves. The earliest modern turbines averaged 50 kW, enough to power only a handful of homes. Also, these early turbines were erected on derricks which made for attractive roosting sites birds, especially raptors which led to unacceptable bird kills. The development of monocoque supporting towers have greatly reduced but not eliminated bird kills.

By the start of the twenty-first century, the average turbine size increased 30 fold. These giants produce about 2 MW. Simple calculations show that the midwestern United States could easily produce all the electrical needs of the country except for the distribution problem – most Americans live near the coasts far from the windy central United States.

The real expansion of wind power will occur with off-shore installations. Most off-shore wind is now located in shallow near-coastal areas, but plans for real behemoths on floating towers are in the works. Each of these 20+ MW plants, taller than the Eiffel Tower, can provide energy for tens of thousands of homes.

Both wind energy production and potential continue to grow. The cost of energy production continues to drop and with the advent of large off-shore plants comes more reliability and less intermittency.

Energy Plus Agriculture

All human endeavors have some impact on the environment be it good, bad, or otherwise. This is especially true when it come to power production. Relatively cheap and available power has transformed the human landscape. Life expectancy more than doubled since the advent of the industrial revolution begun late in the 18th century. The cheap power aided agriculture by greatly increasing productivity and reducing the threat of starvation. Less demand for agricultural labor freed the attention of others to expand an understanding of health care.

However, the negative impacts of the utilization of fossil fuels – coal, oil, and gas – are legendary. In December, 1952 a combination of weather conditions and pollutants from coal smoke killed thousands of Londoners. Oil slicks on the Cuyahoga River in Cleveland, Ohio frequently caught on fire throughout the 1960s. Re-injection of fracking wastes from the production of natural gas has been blamed for recent earthquakes. And then there is global warming and climate change which threaten the planet.

So, power is good, but power from fossil fuels is not so good. The obvious answer is power without the negative impacts imposed by fossil fuels. All the alternatives have some negative impacts but in aggregate, are an improvement.

An interesting combination of technologies is referred to as agrivoltaics, the pairing of agriculture with solar panels to increase farm income. The results from studies here in the United States and Australia are quite surprising.

At first blush one would think that putting solar panels on a pasture would produce energy from the solar panels but the shading would decrease forage production. A study in Australia found just the opposite. Properly spaced and elevated solar panels actually increased forage production. Partial shading was not a significant issue, but the presence of the solar panels reduced loss of soil moisture.

At the same time that the panels help agriculture, agriculture helps the panels. Transpiration of the biomass under the panels lowered the temperature around the panels and increased solar electric output.

An unanticipated benefit was found in a study in Oregon. Panels installed on a pasture on a sheep farm greatly reduced predation of lambs by eagles. The panels provided shelter from eagle strikes.

In a related vein, the marriage of solar panels and water bodies is synergistic. In arid lands evaporation from a reservoir is significant issue. Placing solar panels on pontoons close to the water’s surface reduces evaporation and as before, the cooling effect of the water increases energy production.

Even without the benefit of increased energy production, solar panels can be beneficial. Rooftop systems reduce exposure of homes to harsh weather. Or how about decking over asphalt parking lots? The shade provided will help cool the lot and at the same time provide electrical energy to perhaps charge electric vehicles while the owners shop.

With forethought, energy production from solar panels can be enhanced and simultaneously provide beneficial effects to land use.

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

Renewable Energy Milestone

Renewable energy achieved a significant milestone in April, surpassing coal as the greater source of power for electric generation in the United States. This record may not persist as April is a windy month and because of mild weather less energy is needed for heating or cooling. Regardless, it is a milestone that portends the future.

Electric power from burning coal has been in decline for over a decade. Nuclear power is flat and renewable energy is ascendant. Of the renewable energy sources, wind is the leader followed by solar. Hydropower, geothermal and biomass are relatively static.

Technological advances and economies of scale are responsible for the lower cost and therefore greater penetration of renewables in the electric power production marketplace. Wind turbines are getting larger and taller which makes them more cost-effective in both production costs and efficiency as taller turbines reach windier levels of the atmosphere. As for solar arrays, the advances are mainly in cost reductions due to economies of scale rather than greater efficiency at capturing sunlight.

About seventeen percent of the energy mix is now renewable, and that is dominated by hydroelectric dam generation. In absolute terms, wind produces about seven percent and solar a little under two percent. These numbers are small but the two sources have the greatest potential for growth. Wind energy production has increased a phenomenal thirty-fold since 2000. When it comes to growth, solar is the champ having grown one hundred times faster than wind; that is, a three thousand-fold increase in installed capacity between the year 2000 and today.
One of the beauties of solar is its scalability. Practical installations range from small home systems providing most if not all of an individual homeowners electric power needs up to utility-scale monsters that cover hundreds of acres. Slightly larger than home size installations are those for schools and churches. Even larger installations include power for businesses such as Walmart Supercenters. The real growth, however, is in utility-scale solar arrays.

Entergy, the main supplier for electricity in Arkansas is now producing power from a giant installation near Stuttgart. This facility has 350,000 panels covering 475 acres. It produces enough energy for 13,000 homes. Using this scale of production suggests that every home in Arkansas could be powered from an area less than ten percent of Lafayette County, the smallest county in Arkansas.
Wait just a minute you say, what about when the sun goes down? Not to worry, at least for a couple of decades. Power grid managers won’t worry until intermittent sources reach somewhere between thirty and fifty percent of the total load. Right now wind and solar represent less than ten percent. Two factors are important, source management and grid size. Although wind and solar are intermittent, they are also predictable, and increasingly so.

Utility grid managers have become quite good at wind and sun forecasting. They know about how much wind and solar power will be available in the short term and can effectively plan for alternate sources during those times. The total size of the US power grid adds to the stability. Power can be shipped for one region to another with the flip of a switch – well, that and a more robust national grid of transmission and distribution lines.

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

The Green New Deal

The Green New Deal is a proposal to address global warming and economic inequality. It is widely feared by conservatives as a proposal designed to take away freedom – and cars and money and hamburgers and airplanes. Nonsense.
What it is is a very broad brush plan to eliminate the use of fossil fuels and the release of other greenhouse gases in ten years. Although the timeline is unreasonable, the objective of necessity will be accomplished in the longer term.
Under the plan, sustainable energy sources will be expanded to eliminate the use of fossil fuels for electricity production. Wind and solar with battery backing can eliminate the need for any fossil fuel use for electricity production. This is already underway, as the use of coal has been cut in half in just the last two to three decades.
At the same time, grid-scale batteries are becoming a thing. The City of Fayetteville will soon begin utilizing a ten megawatt solar panel system with energy storage in batteries – intermittency is not an issue with battery backup. Entergy is planning to close two coal fired plants and is building its own solar farms.
In our economy, the transportation sector is the largest user of fossil fuels. Electrification of transportation is in its infancy but happening none the less. Tesla, the biggest manufacturer of electric cars, has sold over a half-million vehicles since they began in 2012. Electric long haul trucks, semis, are in development and will hit the highways in 2020. Electrification of the rails is a no-brainer, it exists already on a limited scale and can be expanded nation-wide.
A tougher nut is aviation. Jet fuel, essentially kerosene made from crude oil, is an ideal energy source as it is very energy dense. To eliminate the use of fossil fuels from aviation will require either of a couple of solutions. The most likely, especially in the short term is to manufacture fuel synthetically from renewable sources.
Biodiesel from oil crops like soybeans is a possibility but would compete with cropland for food production. Better would be the use of waste organic matter as a feedstock for fuel production. This is already happening but needs to be done more efficiently.
Electrification of aviation has already been achieved but is a long way from commercial airlines’ scale. A battery-powered single engine plane with a range of four hundred miles has been flown in England.
The cost of the total conversion to sustainable energy systems will require considerable investment in research and infrastructure, but at the same time it will create quality jobs in an increasingly automated economy. The increased tax revenues from these new jobs can offset some of the costs.
Then there is the issue of what is the cost of doing nothing. Hurricanes in the East, flooding in the Midwest, and wildfires in the West are already costing hundreds of billions of dollars a year and will only get worse from inaction. Our future depends on facing the reality of climate change. The sooner we address the issue the less costly it will be.

Favoring the Sun

Polling shows that a clear majority of Arkansans, 60 to 70 percent give or take, recognize that global warming is happening. Without any polling data, we can only guess the everybody given a choice would favor clean air over polluted air. One method to reduce the rate of global warming and clean the air is to generate electricity from solar panels. Keeping the lights on in a house at night or through a week or two of wintery overcast requires one of two options, a battery bank or buying power from a utility during those periods.

The latter is by far the most common as batteries, where utility power is available, are far more expensive. A common solution is a so-called grid-tied array. People with rooftop solar panels remain connected to the utility grid so that they can get power at night. During the day they can generate the power they need from the sun. To make solar power more attractive most states have some form of net metering.

Net metering is achieved via a bi-directional meter. At night when solar panels are inactive, the meter runs normally, but during sunny periods when the solar panels produce more power than is consumed in the home, the meter runs backward. The homeowner is at these times a net producer, essentially a little power company selling to the utility.

Act 464, 2019 addresses some issues with solar energy production. It allows for third-party leasing. Essentially this allows a homeowner to rent his roof space to another company for placement of solar panels. It also allows for larger net metered arrays so a business can take advantage of the sun to power their facility. A debate exists as to how the solar panel owner is rewarded for their excess production. The simplest and current method in Arkansas is that excess production is rewarded at the same rate as consumption. If in a given billing cycle there is an excess production, credit for that production is carried forward.

Utility executives say that this makes them buy power at a retail rate. Of course, they want to buy power at a wholesale rate, then sell at a retail rate to maintain profitability. But that is an oversimplification. Utilities pay different rates for power depending on demand, so there is no single wholesale rate. High demand times calls for the purchase of expensive “peaking” power. Conversely during low demand times equipment is idled which also has a cost.

Power demands vary by both season and time of day, but one thing is clear. Demand for electricity is always higher during the day than at night. Wouldn’t it be neat if there were a way of producing power during the day when it is needed but not at night so no utility equipment is idled? Solar generated electricity is nicely matched to demand which can serve to lower overall costs to the utility and at the same time clean the air and slow global warming.

The act has good and bad points, but overall it is supported by several environmental organizations.

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

Biofuel from Seaweed

A relatively new contender for a source for biofuels, ethanol from seaweed, has come to the fore. Ethanol is blended with gasoline, commonly a ten percent blend in gasoline or less frequently E-85, a blend of eighty-five percent ethanol with fifteen percent gasoline. The latter is used extensively in Brazil. First a little background on making ethanol by traditional means.

The most common method for making fuel ethanol is fermentation of sugar with yeast. The sugar itself can be had directly from sugar cane, sugar beets or various fruit juices or indirectly from any source of starch such as grains or potatoes. Enzymes obtained from malted barley convert the large polymeric starch into small molecules which the yeast can use as a substrate for fermentation. The process has been known for over five thousand years. The oldest evidence of writing is cuneiform tablets found in modern day Iraq, then known as Sumeria. Some of these ancient tablets have records for beer production and distribution.

Virtually all ethanol produced in the United States is derived from corn and that is a problem on several levels. First and foremost is the fact that the process of capturing energy from sunlight is very inefficient compared to solar panels or wind turbines. Large swathes of land must be dedicated to energy production which otherwise would be suitable for food production. Ethanol from corn also consumes large amounts of fresh water and degrades the soil over time.

Ethanol can hypothetically be produced from plant fiber (cellulose) rather than starch, hence waste plant matter such as grass clippings and leaves could be turned into fuel. Although cellulosic ethanol has been studied intensely for decades, no commercial production has yet been achieved.

Now back to ethanol from seaweed. It’s recently been reported that ethanol can be made from seaweed using a genetically engineered bacteria. This is possible because the chemistry of seaweed is fundamentally different from land plants. Seaweed is comprised of large alginate molecules rather than cellulose or starch.

E. Coli, a bacteria common in the intestines of mammals and birds has been modified so that it has the enzymes necessary to disassemble the seaweed. This releases small molecules similar to sugar just as barley malt releases sugar from starch. A second modification of the genes in the bacteria allow metabolic processes that convert the sugar equivalent to ethanol, hence acting like yeast.

There are a number of advantages to the use of seaweed for fuel production. There is no diversion of food crops to fuel production. Seaweed can be harvested as a perennial crop from coastal areas or salt marshes so there is no impact on freshwater or land erosion. Seaweed production could even have a positive effect in certain coastal areas. Fertilizer runoff from the grain belt ends up in the Mississippi and ultimately the Gulf of Mexico. This nutrient-laden water causes unwanted algae blooms which consume oxygen and create a “dead zone.” If seaweed were farmed in this location it could absorb the nutrients for its growth and then be harvested for fuel production- a win-win situation.

Next time you have a little sake (the ethanol portion ) with your sushi (the wrapper part) consider that it could be coming from the same seaweed, all the while cleaning the environment.

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

Trump Pulls Out

It is now clear now that the current administration has withdrawn from the Paris Agreement for specious reasons. Trump will take us off the world stage, away from 195 countries who do recognize the risks of ignoring global warming, ocean acidification, and climate change.

Global warming as a concept is not new. Svante Arrhenius, a Swedish chemist and Nobel laureate wrote in 1896 on the risks of continued burning of fossil fuels and the resultant accumulation of Carbon Dioxide (CO2)in the atmosphere. [On the Influence of Carbonic Acid in the Air upon the Temperature of the Ground] The concentration of CO2 in the atmosphere had been stable stable for hundreds of thousands of years – under 300 parts per million (PPM). In under 200 years we have raised the concentration to the current value of over 400 PPM, 150% of the value at the start of the industrial revolution.

Despite the relatively simple physical principals involved and despite the evidence from air and water temperatures, rising sea levels, and melting ice President Trump still thinks that global warming is a hoax. He seems fixated on the idea that developing sustainable energy supplies will drag our economy down. Is there evidence of such?

Very simply -No. Germany has installed more solar photovoltaic energy systems per capita than any other country, yet they are running a trade surplus with the United States. On a good day Denmark can produce 100 % of its energy from wind turbines and runs a considerable trade surplus with the United States. Ironically, much of their surplus involves selling wind turbine technology to us. We do have a small industry manufacturing wind turbine blades, but the company is Danish. China has leapt to the head of the pack for producing solar panels and we all know about their trade imbalance.

What do the captains of industry here think? Big fossil fuel producers such as Exxon-Mobil support the agreement. Even coal companies support the agreement. Walmart supports the agreement. Of course forward looking companies like Alphabet, the parent company of Google, Apple, Tesla support the agreement. Polls shows that the majority of Americans in every state, across the political spectrum support the agreement.

The agreement that we are walking away from is first and foremost voluntary. The agreement would in no way allow foreign influence of our laws or sovereignty. The agreement calls for international goals for reducing the rate of global warming by reducing the release of CO2 and other greenhouse gasses.

The US goal was a reduction of greenhouse gas emissions by 27 % of 2005 emissions by 2025. This is doable with a combination of energy efficiency, sustainable technologies such as wind and solar and switching from carbon intensive coal to natural gas. These changes to our economy are already underway and by participating in the agreement we show the world that we care about collective actions for all humanity, even for all life on this planet.

By not joining the agreement we turn away from 195 countries and join with Syria, torn by a violent civil war, and Nicaragua, who thinks the agreement doesn’t go far enough.

PV Primer, 2017

The cost of photovoltaic systems (panels and inverter) has dropped to about 1 to 2 dollars per watt. At this price, including the 30 % federal tax credit, systems have payback times in less than 7 years, regardless of size. This assumes a cost of about 10 cents a kilowatt hour (kW-hr) for electricity.

Here are a number of nuts and bolts issues for those interested in solar power. First and foremost you must have a location with southern exposure. Even a small amount of shade can seriously reduce energy production. For most this means a roof top location, but it needn’t be if you have the space to put the array on the ground. The simplest mounting puts the panels flat on the roof. The pitch of the roof is not all that important as long as it faces south.

The amount of space needed for an array of course varies as to how much total power you want to produce. Different manufacturers make panels in different sizes (watts) but the total space needed is the same because all PV panels have the same efficiency, about 15 %. Five 100 watt panels will take up the same space as one 500 watt panel. One kW requires about 80 square feet of space.

A big decision is whether the array is isolated or connected to the electrical grid. Grid-tied systems here in Arkansas can take advantage of net metering. This means that the power produced by the panels can actually make a meter run backwards if they are producing more power than the home is consuming at any time. About the only disadvantage of a grid-tied system is that when the line goes down, so does the solar power production. This is necessary to protect power line workers.

The alternative to grid-tied is to go entirely off line by buffering production with batteries. This avoids the aforementioned problem, but greatly increases the cost and “hassle factor” of the system. This is only practical when connection to the grid is cost prohibitive, as in remote locations.

The total amount of energy produced by a system is obtained by the total wattage of a system. For example a 1 kilowatt system can produce a maximum of one kilowatt hour only when the sun angle is ideal. Averaged over a year, a simple rule of thumb is that you can get 4 hours of net production per day. Hence a 1 kW system can be expected to produce 4 kW-hrs per day, more some days, less others.

Let’s use an average consumption of 1000 kW-hrs per month (close to the average in Arkansas) to determined a system sized to replace 100 % of electric needs. 1000 kW-hrs per month means 33 kw-hrs per day. Divide that by 4 to get a a little over 8 kW system. To allow for some inefficiencies say we use a 9 kW system. At 1.5 dollars a watt, the total cost would be 13,500 $. The 30% federal tax rebate brings the final cost down to 9,450 $. Sales taxes and installation will add to the cost, but these numbers can be used to approximate a cost if you are interested in going solar.

Wind Power Transmission Line

A federal decision on the Plains and Eastern Clean Line High Voltage Direct Current line is imminent. This proposed 700 plus mile long transmission line will extend from the panhandle of Oklahoma, through Pope County, and on to Memphis. If approved and built it will allow for the movement of large amounts of wind generated power from the midwest to parts east where it can be used to replace coal fired generating plants.

The route already approved by the National Environmental Policy Act (NEPA) will pass through central Pope county. A substation just north of Atkins will allow Arkansans a piece of the power from the line. For perspective the line will cross Big Piney Creek near where it crosses Highway 164.

The line and others like it are necessary to reduce our need for coal which fouls the atmosphere in multiple ways. There is a superabundance of clean, relatively inexpensive energy waiting to be tapped in the midwest, the only need being transmission.

The Line is not without its detractors however, especially those in the path of the powerline right-of-way (ROW.) It will require a couple of hundred foot wide ROW with 150 foot towers spaced about 5 to the mile. The land within the ROW can be used safely for any purpose with the exception of forestry – crops, hay fields, and pastures are acceptable uses for the area. Landowners will be compensated for the ROW but they complain that compensation is insufficient.

It really boils down to “Not In My Backyard” (NIMBY.) This is not surprising, nobody wants their view of a skyline marred by powerlines. But powerlines are a fact of modern life. Anyone who is connected to the electrical grid benefits from numerous folks having yielded a ROW to get that power to their home or business.

One suggestion to remove the negative visual impact would be to bury the line underground. It has been done locally on a very small scale. In some newer subdivisions the distribution lines are buried but not for far, as it is quite expensive compared to overhead lines.

The relative cost of burying high voltage transmission lines is assumed to be prohibitive as it is just not done with the exception of lines that cross large bodies of water where it is the only possible alternative.

To bury a transmission line requires serious disruption, trenching then back filling, not just pastures and hay fields but sidewalks, roadways, and even rivers and wet lands. For forest land, a clear cut ROW would be necessary to be able to bring in the heavy equipment necessary to excavate and lay the line.

One of the benefits of buried lines is that they are less susceptible to weather related outages. The other side of the coin is when an outage occurs in an underground line it is harder to locate and harder to access, changing repair times from hours for overhead lines to weeks for underground lines.

Cost estimates are in the range of 2 to 10 times more expensive than overhead lines. Power companies across the land, whether private like Entergy or public like the Arkansas Electric Coops, have made the decision to stay with overhead lines, wherever possible.

State Support for Sustainable Energy

The data are in and the numbers are crunched. 2015 is officially the hottest year for the planet in recorded history. Last year raced past the previous hottest year, 2014. In fact the 10 hottest years on record have occurred since 1998.

The science is clear, the heating is due in the main to burning fossil fuels. Governments around the world are developing strategies to decarbonize their economies. Here in the United States we have federal various tax credits which lower the cost for both individuals and businesses to be less reliant on fossil fuel combustion. Purchase tax credits are available for energy efficiency and sustainable energy production. Also, production tax credits for wind produced energy are available.

Variable levels of subsidization from the states for both purchase and production of sustainable energy is also available. These can come as purchase savings: income tax credits, income tax deductions, sales tax rebates, and cash rebates. Production of sustainable energy, for example solar photovoltaic systems or wind turbines are subsidized by feed-in tariffs or net metering. Levels of support also vary by sector such as homeowners, coops, or for profit businesses.

California is generally recognized as the nation’s leader in clean renewable energy because they have committed to a renewable portfolio of 50% by 2030. This means they expect 50% of energy production in the state to come from renewable energy. Their success thus far is driven by a combination of all the above, credits for efficiency, the purchase of equipment, and for energy produced.

An example of a production subsidy is a feed-in tariff. This is a rate structure for electricity where the producer of clean energy, say a homeowner with solar panels, signs a long term contract to produce energy to the grid at a premium price. In Michigan the average cost of electricity is about 11 cents a kilowatt hour (kWh). Producers with a feed-in tariff are paid 24 cents a kWh. Payback times at this rate could be less than five years!

Here in Arkansas we are about in the middle of the pack, renewable energy support-wise. There is essentially no state purchase support, but net metering provides some assistance for the production of clean, carbon free energy. Net metered systems in Arkansas use bidirectional meters. When the sun shines and production is in excess of consumption the meter runs backwards, at the same rate as it runs forwards when consuming energy. There no additional access charge or fee for net metered systems. What this means is that the home producer is paid retail cost for the power sent to the grid.

Less valuable but still of some help are net metered systems where the producer is only paid the power company’s avoided cost, the wholesale rate. This doesn’t reward the expense of providing clean power to the grid as the avoided cost is the cost of the oldest, cheapest, and usually coal fired power production. Nevada recently downgraded their net metered systems to pay only the wholesale price for production, rather than the retail price.

Only two states, Tennessee and South Dakota, have no production support for distributed clean energy.