Tag Archives: wind power

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.

Intermittency Need Not Be a Problem

There is no question that the future of power will be from the sun. Wind generation and solar panels are the predominant contenders. The president has wrongheadedly bragged about bringing back coal as an energy source. It hasn’t nor will it happen for simple economic reasons. Natural gas generation of electricity is cheaper and wind and solar are rapidly approaching parity in cost. Burning coal has the additional unaccounted burden of fouling our air and water.

The only advantage that fossil fuels have is that once extracted, they are available for power production near continuously. Sustainable sources such as wind and solar are available only intermittently. The relative availability is referred to capacity factor (CF), the fraction of time when a power source is available. Generally fossil fuel consuming power sources have higher capacity factors than intermittent sustainable sources, but are by no means constant.

The point of this is that all our electric generation sources are intermittent to a degree but power demands are continuous. At times less power is needed such as at night, or during the spring and fall when less heating or cooling is needed. Interconnected grid systems match power production and demand by balancing the various sources. Sustainability experts estimate that we can introduce intermittent power sources into the gird up to about 30 % of our total production without changing anything. After that we will need to add storage or change the way we utilize available intermittent power production.

Most think of batteries when considering electricity storage, but it is not the electricity necessarily that needs to be stored but rather the potential. Pumped storage is an example of the latter. In several locations, excess power at night can be used to pump water up a hill into a storage reservoir. During the day when demand increases water can be released to generate power.

Another strategy is to match jobs and/or lifestyle to the availability of electrical power just like we do for other traditional activities. We don’t grow corn and beans in the winter. We don’t go downhill skiing in the summer. In some locales power consumption is managed on a small scale with time of day pricing of electricity. Generally there is less demand for electricity at night, so power companies lower the price at night. This influences people to shift power consuming activities to later hours.

Larger scale operations could be shifted to times when energy is more available. The upper midwest has abundant wind energy available. It is available intermittently but predictably. Manufacturing schedules could be matched with the availability of lower cost power.

Solar power could easily be matched with power needs which themselves are only intermittent. Huckleberry Creek north of Russellville, Arkansas is a 500 acre man-made impoundment. It provides drinking water and in most years is sufficient. On occasion water is pumped from the Illinois Bayou uphill into the impoundment. Pontoon mounted solar panels could be floated on the lake to provide pumping power. There are a couple additional advantages here. Evaporation would be reduced by panel coverage and the solar panels themselves would be more efficient due to cooling from the water.

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.

Pipelines and Electric Lines

Over the coming months two major public service transmission lines will be installed across Pope county. One is a high voltage direct current (HVDC) electric transmission line from the panhandle of Oklahoma to Memphis, Tennessee. The other is a pipeline to move oil from Cushing, Oklahoma to Memphis. One will contribute to a clean energy future, the other will contribute to global warming. Both will, to the point of law suits, incense landowners along the rights of way.

Cushing Oklahoma, because of location and historical precedent, is the major hub for oil pipelines in the United States. It also happens to have the largest oil storage tank farm in the world. The Diamond pipeline will move 200 thousand barrels of light sweet crude per day to a Valero refinery in Memphis. To get a sense of just how much oil that is, if the pipeline were diverted it could fill the Dallas Cowboys stadium in less than a day. If the oil were all converted to gasoline, it could fill the tanks of half a million cars a day.

Opposition to this 900 million dollar project comes from landowners who would rather not have a 25 to 150 foot wide strip of land which must be maintained as an open space – no forestation or permanent structures in the right of way. The pipeline is also opposed by environmental groups who would rather not have more crude oil turned in to fuel which ultimately contributes to global warming.

The panhandle region of both Texas and Oklahoma have some of the best wind resources in the country. Wind speeds average near 20 miles per hour. It is a problem however as there is no market for all the potential wind energy in the area, hence the need for transmission lines to take what energy could be generated elsewhere. Most practical is transmission to the east across Arkansas to a distribution hub in Memphis. This will allow for clean renewable energy to replace energy from coal fired power plants across the Tennessee Valley Authority power grid. It also will require a 150 or so foot right of way.

The HVDC transmission line will carry 4,000 Megawatts of direct current electricity about 700 miles start to finish. Power poles are 150 feet tall and spaced 5 to the mile. This power line is like a super highway for electrons with very limited access. The only “drop-off” point planned currently is an off ramp near Atkins. This will allow 500 Megawatts of power to flow into the local grid.

Like the oil pipeline, land owners are opposing the HVDC line. The nation’s preeminent environmental group, the Sierra Club, is supporting it.

Both project require regulatory oversight which allows the use of eminent domain to secure the rights of way. The process is different for the projects. The oil pipeline has been approved by the Arkansas Public Service Commission (APSC) even though the Pipeline will provide no direct benefit to Arkansas. Apparently pipelines get a legal pass, not afforded to the electric transmission lines.

Because the initial HVDC line had no direct benefit to Arkansas, it was denied legal status by the APSC and therefore is seeking federal oversight. By partnering with the Department of Energy Clean line will gain federal right of eminent domain.

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.

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Alternative Energy Alternatives

So you want to be green, or at least greener, when it comes to your electricity use. There are a welter of options available. Here in Arkansas we are not blessed with sufficient wind resources to make homeowner wind very cost effective, so going green means solar photovoltaic systems (solar PV) are the best game going. But with this restriction there are still several different approaches to decarbonize your electricity.

In remote areas without grid connections, the only reasonable green electricity is with a solar PV system and batteries. The batteries are necessary not only to tide you over for when the sun doesn’t shine but also to stabilize the power to your home or cabin. Imagine on an otherwise sunny day a solar array is providing nicely for the home, but a cloud passes over. This would temporarily reduce the current, possibly to the point of damaging electronics, Hence batteries are essential. Just how many batteries needed is a function of how long will the sun not keep up with demand. On occasion in this area we can go for a week or two without much sun due to rain and clouds. The point is that this is the most expensive option due to the costs associated with the batteries.

Much more practical are so called “grid tied” solar arrays which essentially use the electrical grid as a battery. If you buy electricity from Entergy, SWEPCO, or AVEC for example, and you add solar panels to your home, the power company is your battery. When the sun shines your meter will slow down or actually run backwards sending power to the grid. At night or on rainy or cloudy days power is drawn back from the grid. Because Arkansas is a net metering state, when producing you are paid the same price as when you buy. Depending on how many panels you have you can replace some or all of your electrical needs. Currently costs are such that the payback period is about half the rated lifetime of the panels. You will recoup your initial investment in about a dozen years, and the panels will continue to produce for at least that many years to come.

All homes don’t have access to the southern sky on their property due to shading from trees or the terrain. That said you can still participate via community solar farms. The first community solar farm has begun near Little Rock. A developer is constructing a solar farm tied to Entergy’s grid. Any Entergy customer can basically buy a piece of the solar production. The buyer has their own meter which is aggregated with their home meter, just as if the solar panels were on their roof. Entergy deducts any power costs produced by the solar panels from the power costs at the home. The cost for this approach is somewhat higher as because of the costs for site development and land acquisition.

Yet one more option exists to green up your electricity. The green power costs for the aforementioned approaches all require some significant start up costs. Another alternative is to buy “green tickets” or participate in the purchase of Renewable Energy Credits. There are companies that will for a nominal charge on top of your actual electric bill, buy green energy. The additional charge is used to buy power from green sources and send that electricity to the grid, which offsets electricity from fossil fueled sources. Basically you are subsidizing clean energy. You don’t own any equipment but your dollars go to green the environment.

Private Sector must be the Answer

In Al Gore’s award winning movie “An Inconvenient Truth” he used the old saw to depict a real problem with global warming. If you put a frog in hot water it will immediately jump out. Put a frog in cold water but very slowly warm it up and the frog will stay until it is too late and be boiled alive.

That is a nice analogy for the dilemma we face with with global warming. The process is slow. Another analogy would be to call it glacially slow, but glaciers are moving, and melting, at a fairly rapid pace these days. Humans and a number of animals evolved to react to rapidly occurring threats – the snap of a twig in the brush, the glint of light from an eye, and we are ready to fight or flee.

Global warming is a decades to centuries change that threatens us now, and many just don’t see the threat, a threat not to us individually, but to our future. Some are so insensitive to the risk that even if they believe it to be true, won’t react because it doesn’t matter to them personally. If the majority of us hold this opinion, we are doomed as a species.

Some governments are beginning to react with policies that favor carbon free energy strategies, but the steps are often small and can be more costly than simple business as usual burning of fossil fuels. Hey, it’s on face value cheaper and we know how it works.

On a more hopeful note is the fact that technology got us into this problem, but technology and the private sector, hold the potential to get us out. Obviously we need to stop burning fossil fuels, especially coal and oil. Natural Gas, essentially methane, is does not produce as much pollution as the others, but ultimately its use must be curtailed also.

There two ways to replace the fossil fuels, use less through efficiency and replace energy production with non-carbon sources such as wind, solar and geothermal. Of the three, wind is the most developed. We currently get about 4 % of our electric energy production from wind, entirely land based. The potential for off shore wind, especially on the east coast affords considerable potential but currently is more expensive to exploit than wind resources in the midwest. Currently the cost of wind generated power is as cheap as that from a modern coal fired plant. And the costs continue to decline, the opposite of the cost for producing power from coal.

Solar Photovoltaic systems (solar panels) are sprouting up everywhere, especially since the price has dropped by half in just the last few years. Not only are homeowners adding panels to their roofs but utility scale systems are being installed. Entergy recently announced that they intend to build a 500 acre solar farm near Stuttgart. For perspective, a square mile covers 640 acres.

Until the intermittent energy sources of wind and solar penetrate to about 30% of total production, no additional back up power is needed. Essentially there is enough existing reserve power to keep the lights on after dark when the wind isn’t blowing. Beyond that, battery backup will be needed. Development and deployment of utility scale battery production will surely follow the demand.

World Wide Wind

We will at some point cease to produce electrical energy by burning fossil fuels, either (sooner) because we realize the harmful effects of using the atmosphere as a toilet, or (later) because we simply use them all up. These fuels can be replaced with sustainable sources, principally wind and solar. Where are we now and where are we going?

In the United States we currently get 13 per cent of our electrical power from renewables. The majority of that from hydropower, followed by wind biomass and solar power as a distant fourth. There seems to be limited potential for growth in hydropower or biomass but the sky the limit for wind and solar, assuming that the issue of intermittency can be overcome.

Although we have no national policy for the country, president Obama has mandated that the federal government get 20% of its electrical energy from renewables by 2020. Various states have renewable portfolios that range from trivial to ambitious: The old south, a couple of coal states in the Appalachians, a few midwest to rocky mountain states have none. Hawaii has the most ambitious, with a target of 40% by 2030.

Internationally, it’s a mixed bag. Mountainous Costa Rica, with a population of about 5 million, gets from 90 to 100% of its electrical energy from renewables, mainly hydro and geothermal. Similarly Norway with twice the population of Costa Rica produces very close to 100% of their electric power from hydropower plants.

Because of availability of cheap electric power they have developed energy intensive industries such as the production high grade Silicon for solar cells. Interestingly a focus of World War II was on Norway. Germany invaded Norway to gain access to energy intensive production of heavy water for their experimental nuclear reactor program.

The real potential for expansion of renewable power is in the wind, especially in countries with lots of coastline. At one point last week, Denmark was producing 140 % of its electrical energy, exporting the excess to Sweden and Germany. Their current average wind produced electricity is approaching 40%, and they are still building out.

Germany is an interesting study. They have a vigorous low carbon energy transition plan (Energiewende.) Their target is an astounding 80% renewable by 2050! They are currently installing wind and solar PV faster than anybody on the planet. Currently they are around 27% with very little hydropower, twice the US average.

The biggest player of course is China. They are the current world leader in carbon emissions, having surpassed the US a few years ago. China’s air pollution problems are legendary. Smog from from eastern China can be tracked across the pacific to our west coast. They recognize they have a problem and are aggressively addressing it by moving away from fossil fuels and toward efficiency and renewables. In 2014 they installed three quarters of the new solar capacity on the planet.