Tag Archives: carbon-free energy

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.

Carbon and Taxes

There are a number of ways to raise money to pay for the various and sundry functions of government. Here in the United States we use many different taxes. At the local level, say county and city, the emphasis seems to be on real and personal property taxes and sales taxes. At the federal level income taxes predominate. There are many variations on these taxes such as luxury taxes, estate taxes, capital gains taxes and special exceptions, i.e, tax deductions, but a common theme runs through them all. In addition to raising money for the operation of the government, taxes are aimed a social policy.

Progressive income tax rates, dependent allowance for income taxes, sales tax exemptions for food and drugs, deductions for mortgage interest and child care to name just a few. The result of all this is a rather arcane web of taxes that keep certified public accounts and tax lawyers in the the tall cotton. It could be simpler, for example we could get rid of all deductions and exemptions.

Much of Europe uses a VAT or Value Added Tax. Basically this is a sales tax on the increased value of an item. Iron ore is minded to make steel, which is used to make pipe, which is used to lay an natural gas line. At each point the value of the product increases and that increased value is taxed. A similar tax has been proposed in the US called a “fair tax.” This is a 30 % tax on sales of goods and services. The rate is set to be revenue neutral, that is it would replace other taxes but neither increase or decrease net revenue.

The flaw with any tax is that it punishes some activity. Some are intentional such as sin taxes, those on the sale of tobacco and alcohol, but others aren’t meant to punish but do just the same. Income taxes punish income (work), sales taxes punish sales (business), and capital gains taxes punish savings.

We have to collect taxes and that collection inherently punishes some activity. An alternative promoted by environmentalists is a pollution tax. The tax rate could be calculated to be income neutral, and the tax rate of a polluting activity could be based on the importance of the pollutant. The most mature of these pollution taxes is called a carbon tax, actually a tax on Carbon Dioxide released on combustion of fossil fuels. Over ninety per cent of of fossil fuels go to the generation of energy (do work), the remainder being used for the manufacture of plastic bags and axle grease.

The carbon tax would embed an additional cost for heating your home, fueling your car (and the trucks and trains that move the goods across the country,) and keep the lights on in your home, as long as this work was done via fossil fuels.

An most important added value of this form of taxation is the favoring of clean energy production. Solar, wind, and geothermal processes do produce useful work but don’t pollute so wouldn’t be taxed. This would greatly stimulate the adoption of sustainable energy for our future.

Booming Solar

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Sustainable energy is currently the most rapidly expanding form of energy in the United States. The same is true here in Arkansas. Whereas we are not well set for wind as our neighbors are to the west, solar panels (PV) that generate electricity are effective, and getting cheaper by the day. Solar arrays now cost less than half of what they cost just 10 years ago.

The price is now so low as to be competitive with more conventional power sources such as coal and natural gas, and infinitely cleaner. Current solar capacity (as of 2015) is 20.1 megawatts (MW.) This is an unbelievable 640 % increase over all PV power installed up through 2014. The new power installed in 2015 is dominated by utility scale power, 15.4 MW. Commercial industries and businesses installed 0.24 MW and the residential sector 0.46 MW. This represents a 56 million dollar investment in clean energy and jobs.

Solar power has come of age, not just for people wanting a little power for an off-grid cabin in the woods, but residents tied to the grid, industries, and especially power companies. One real advantage of solar power is its scalability. If a power company needs to expand their energy supply a small amount, they can add a small solar field. If they need a lot of power, they install a bigger field. No alternative has this scalability. You just can’t build a (cost effective) small coal or nuclear plant. Not even natural gas fired turbines are as scalable.

The L’Oreal plant in North Little Rock will install several thousand PV panels, about 1 MW’s worth. In March 2016 a private-public consortium consisting of two Arkansas Electric Cooperative Corporations, and Aerojet Rocketdyne will install a 12 MW solar field near East Camden. The largest install this year will be an 81 MW solar farm to be installed by Entergy near Stuttgart.

Generally installs of home solar arrays are booming also. Most cost effective for the consumer is a grid-tied net metered array. This system allows the home owner to remain connected to the grid in addition to the solar panels. When the sun shines the panels provide energy to the house, but when the sun is not shining, the home can draw power from the grid just like any other home.

PV systems can be sized to provide all or any fraction of the power needed for the home. If a particular array actually produces more energy than can be consumed in a given month, the law allows the excess to be carried over to a month when energy is needed.

The consumers gain is however the power companies loss, and they don’t like it. They lose profits by not selling as much electricity and even worse net metering threatens the vertically integrated structure of the business. They are the power generators, the wholesalers, the distributors and the retailers, and they want to keep it that way. Other states, notably Arizona and Oklahoma, have instituted additional fees for home solar which will severely limit the development of truly distributed clean energy.

The Public Service Commission here in Arkansas is empowered by law to set rates and rate structures of electric utilities. Over the next year they will be conducting studies to determine if changes are needed (read additional costs to home solar users.) The utilities will be arguing that they have to claw back their profits to remain in business. Stay tuned.

Solar Based Solar Energy

A major drawback of most if not all sustainable sources of energy is the matter of intermittency. Power can’t be generated by wind turbines if the wind doesn’t blow, and solar panels don’t generate power when the sun doesn’t shine.

There are three ways to deal with this. One is to simply expect to use power when it is available. This is impractical for homes or hospitals or industries where power is necessary 24/7, but it is conceivable that certain industries could run their industrial processes when power is available. Sources such as wind and solar are intermittent, but reliably so. A major problem with this strategy is that expensive equipment can’t be used for sizable amounts of time, making the industry less efficient and therefore less competitive.

The obvious solution is energy storage for leveling the availability of power, and there are a number of different strategies. Pairing energy sources to level access to power may be possible in some cases. In some areas the wind blows more at night. This could be combined with daytime solar PV. Actually this is already occurring to some degree via our electrical grid that utilizes both wind and solar inputs.

The holy grail of sustainable but intermittent energy is inexpensive grid scale battery storage. This is a major forefront of sustainable energy research today. Some Japanese researchers are taking another tack however. What if you could find a place to put solar panels where the sun always shines, with no shadows or clouds, just sunlight 24/7. No problem, just head out into space about 20,000 miles. Solar panels are already hard at work powering hundreds, even thousands of satellites and of course the international space station.

The Japan Aerospace Exploration Agency (JAXA) has a 25 year plan to develop gigawatt scale solar panels in space and then beam that energy back to earth. For perspective the average nuclear power plant produces a little less than a gigawatt. The two reactors at Arkansas Nuclear one combined output is about 1.8 Gigawatts.

This will be a BIG project. To produce that kind of power requires an array of solar panels that weigh on the order of 10,000 tonnes and covers an area of a couple square miles, but this is the easy part. Getting that power back to earth is the really tricky part of the plan. The idea is to beam the power back from space via microwaves. Satellites in geosynchronous orbit would point a sending device towards an earthbound antenna which would absorb the microwave power, then convert it to electrical energy that could be sent to grid along with all the other energy sources.

We use microwave ovens to heat up cold cup of coffee, but in this application the power is sent only a few inches, not tens of thousands of miles. Microwaves are sent long distances in the form of radar, but the relative power level is extremely low. To beam relevant amounts of power tens of thousands of miles is the real challenge.

So far testing has only involved sending kilowatts of energy over a fraction of that distance. Stay tuned.

RIP David Bowie 1947-2016

pv2

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.

Don’t Buy Oil

The horrible terrorist attack in Paris has drawn a number of responses as to what to do. Both French and US forces have launched bombing raids against ISIS forces in Syria. Many are calling to again put “boots on the ground” – a euphemism for send sending more of our sons and daughters off to die. With irrational fear trumping compassion, many governors want to have nothing to do with refugees from Syria.

Nether war nor fearfulness will solve our problems. It is time for a different perspective. The chaos in the middle east cannot continue without money to pay the fighters and buy the weapons and ammunition. Much of the money to fund the terrorists comes from the sale of oil. A step was taken with the bombing raids recently when over a hundred oil tanker trucks were destroyed. These were tankers that ISIS used to sell oil on the black market. As long as they have access to the oil, ways will be found to sell it. Additionally cash from the Gulf States flows directly to ISIS. It is not the official positions of the governments of the Gulf States, but rather private donors, made rich through the sale of oil, who are contributing to ISIS.

If the terrorists will find a way to sell the oil they control, and the riches of the Gulf States donors will continue to flow to the terrorists, what is to be done? Starve the beast. Stop buying oil. Not just the black market oil or the oil produced by the Emirates, but all oil. If we don’t buy the black market oil, we go somewhere else to buy oil. But someone else will buy the oil. Same for the Gulf States oil. We buy instead from Venezuela or Nigeria. But then someone else buys the Gulf oil. The problem is that oil is a very fungible commodity. Within limits, oil is oil, no matter where it comes from.

The answer is to stop using and therefore stop buying, oil. If we completely withdraw from the market, we will effect a dramatic drop in the price of crude oil. It’s a simple matter of supply and demand. We in the United States constitute a scant 5 percent of the world population, we consume over 20 percent of the world’s resources including oil. The drop in prices means less revenue from the sale of the black market oil and lower revenues for the emirates, hence less money to fuel terror. Transitioning to an electric economy fueled with wind and solar has its costs, but so does waging war.

Transitioning away from the use of oil will happen eventually as oil on the planet runs out, why not start now and help to stabilize geopolitics in the process. Why not start now to reduce pressure on the climate that comes from burning the oil? Why not stop now to help clean the air to reduce health care costs. A final benefit would be that we could become world leaders in sustainable energy technology.

Fuel Cell Vehicles

Auto manufacturers, both here and abroad are scrambling to produce electric vehicles. The most successful out of the gun has been the high end Tesla model S. Others include the Nissan Leaf and BMW i3. Chevrolet will be introducing the Bolt in the near future. All these cars are whisper quite and perform well. They all however suffer the drawback of limited range on a charge and a rather long recharge time at least compared to the time to fill a tank of gasoline.

Notably missing from the cars listed above is the world’s largest car manufacturer – Toyota. They set the standard for hybrid cars with the introduction of the Prius in 2001. It is powered by a internal combustion engine (ICE) which is supported by a electric motor and battery that results in quite high mileage compared to other ICE powered cars.

Although Toyota has yet to produce an all-electric car, they seem to be hedging their bet on the development of an alternative to electric cars with batteries. In development is an electric car that runs off of a fuel cell that is powered by Hydrogen. The chemistry of the fuel cell is just the opposite of the high school CHEM class experiment called electrolysis. If you pass an electric current through water it cause the production of Hydrogen and Oxygen from the water. This process consumes electrical energy.

In a fuel cell powered vehicle, hydrogen gas is stored at high pressure in a tank. When electrical energy is needed, the gas is passed into the fuel cell where it combines with oxygen from the air to produce electrical energy. The principle is simple but in practice fuel cells are complex devices that require unique and often expensive catalysts to make the chemical reaction proceed at a sufficient rate to power a vehicle. The real advantage to this technology is the range of the vehicle between refills. It should be possible to store enough Hydrogen in a vehicle to get a lot more range than can be achieved with charging batteries.

A problem with the use of Hydrogen is one of thermodynamics. It takes more energy to produce Hydrogen than you can get back when used. Basically any time you do work, energy will be wasted. Thermodynamically work is the use of energy to drive a process, be it chemical , electrical or mechanical. In the case of Hydrogen energy losses occur when it is created from water by electrolysis, when it is compressed for transportation, when it is decompressed for use, and when it is used in a fuel cell. Each of these processes constitute an inefficiency where energy is lost.

Another problem is that Hydrogen is a gas and somewhat difficult to handle. Hydrogen stored in metal containers, or piped in metal pipes causes embrittlement. The metals become more fragile and likely to fail under pressure on exposure to Hydrogen. It is also problematic in that it has a low energy density by volume. It takes a lot of space to store a given weight of Hydrogen.

Toyota is betting that these difficulties with the production, storage and utilization of Hydrogen can be overcome.

Arkansas and the HVDC Power Line

Plains and Eastern Clean Line has proposed and are planning the construction of a 700 mile High Voltage Direct Current Power line stretching from the Oklahoma Panhandle to Memphis. The 600 kilovolt line will have the capacity to move 3.5 GigaWatts of power, equivalent to the output of 5 or 6 coal fired power plants. This represents a major move to deliver excess clean, wind-generated electricity out of the midwest to markets to the east.

wind turbine blade

wind turbine blade

Similar projects are in progress to our north, the Grain Belt Express Line will be passing through Missouri on the way to St. Louis and points east and the Rock Island Clean Line which will pass through Iowa and tie into several eastern states.

These projects are not so much about the here and now, but rather the there and then. Multimillion dollar projects take long lead times between inception and completion, usually several years, so they have to be planned with the future needs in mind. The recent requirement by the EPA to reduce our nations carbon emissions only hastens our need for clean renewable electrical energy to replace obsolescent coal fired power plants.

The lines have both supporters and detractors. Environmental groups usually favor the projects as a way to reduce carbon emissions and thus reduce the risk of the damaging effects of global warming. On the other side are land owners who see the power lines marching across their land as more big government intrusion into their lifestyles and even interfering with their livelihoods. Additional arguments against construction of the lines are possible health effects, and the fact that the entities proposing the construction are private companies.

It seems strange that an argument against private industry would be made. The United States to a very large degree operates that way, it’s capitalism, right? Rights of way (ROW) must be secured for these power line projects private or otherwise, just as any project in the public interest such as water lines or a railway. Fair market price must be paid for any property taken for the ROW.

Because these are direct current lines they have a relatively small footprint, at most about 200 feet wide.

Monopole_structure

Monopole_structure

The total area utilized by the Plains and Eastern Clean Line is about 8000 acres spread over the total roughly 300 miles in Arkansas. The actual land area taken out of service is much less than that as grazing land and hay fields are essentially undisturbed even within the ROW.

Health effects of the power lines relate to several phenomena – Induced magnetic fields, possible corona discharge, and ion production. There is no convincing evidence based on years of experience with power lines that any of the aforementioned causes have health effects.

The magnetic field induced by the proposed line is about the same as the earth’s magnetic field. A few meters from the edge of the right of way won’t even deflect a compass. Power transmission line operators design equipment to avoid corona discharge as it wastes power. With respect to the ions generated, if you worry about power lines, stay away from beaches and waterfalls as they produce even greater numbers of ions.

In the interest in full disclosure I am a member of the Arkansas Chapter of the Sierra Club which has endorsed the proposed power line.

Ivanpah tower

Solar Thermal Electricity Generation

After spending a near cloudless weekend on the Buffalo National River, my thoughts turned the considerable power of heat from the sun. When concentrated the sun’s heat can be used to do work, specifically generate electricity.

A new facility has begun operation near the Nevada border in the California desert. Ivanpah, CA in the Mojave desert is home to a solar thermal power plant covering a little over five square miles. The plant produces enough energy to power 140,000 homes (377 megaWatts.)

The plant consists of three towers each surrounded by thousands of mirrors.

Ivanpah plant

Ivanpah plant

Computers control where the mirrors are pointed such that they are always pointed at the top of the tower. There boiler tubes convert water to steam to at very high temperature and pressure. This is used to turn turbines for the generation of electricity. It works just like a conventional coal or nuclear power plant, but without the carbon emissions or radioactive waste. Clean sustainable energy.

Solar thermal power technology is not really all that new. A solar thermal power system was demonstrated at the the 1878 World’s Fair in Paris. A 20 square meter parabolic reflector, basically a light concentrating mirror, was used to make steam to run a printing press. Other solar thermal plants employing power towers have been built but the Ivanpah plant is by far the world’s largest and most efficient.

It is very efficient in multiple ways. Solar photovoltaic plants, usually seen on rooftops, are also configured in large numbers in fields to produce power for the grid and operate at about 15 per cent efficiency. The Ivanpah facility captures upwards of 20 per cent or more of the sun’s energy.

A unique feature of this solar thermal plant compared to other sustainable but intermittent power sources such as wind and solar PV is the ability to generate power around the clock. Some of the day time heat energy from the plant can be stored in special insulated reservoirs containing molten salt solutions. At night, generators can be run off of steam produced by water circulated through the heat storage reservoirs.

Another important variable in any thermal power plant is water use. This is especially important in the desert. When water is heated to make steam, it can only be used to do work if and when it is cooled back to water. Cooling the steam can use lots and lots of water. That’s why you see thermal plants like coal or nuclear fired plants located near large bodies of water – rivers, lakes, even sea coasts. The Ivanpah plant uses an air cooled system to condense the steam so it is particularly frugal when it comes to water use.

To complete the discussion I should mention downsides, two come to mind. First is land use, solar thermal plants of this type require relatively large areas in sunny climates. Luckily we have much desert land that with proper oversight to protect natural habitat can provide a significant amount of electricity production.

Finally there is the issue of bird kills. Some species of birds, especially fly catchers are being killed by flying into the heated air near the towers. Estimates are that about 30,000 birds are killed per year. That may sound like a lot but compare that with the number of birds killed annually by collisions with man made objects. A billion, yes that is a billion with a capital B, birds die from running into windows, and towers and what not.

CO2

Clean Air, Stable Climate

Section 202 of the Clean Air Act requires the EPA to regulate any pollutant which in their judgment may reasonably be anticipated to endanger public health or welfare. Previously this had been applied to acute respiratory toxins such as sulfur and nitrogen oxides or substances which contribute to their formation.

After an extended court battle the United States Supreme Court ruled in 2007 in favor of the EPA that regulating green house gases (GHG) is a requisite part of the EPA’s mandate. Greenhouse gases, principally Carbon Dioxide trap heat in the atmosphere and because of the threat of global warming endanger the public health and welfare.

Rule making took several more years but now the regulations have begun to roll. The first to feel regulation was new power plants which had to meet stringent emissions standards. Likewise emissions standards for new cars continue to rise.

auto_smog

auto_smog

The most recent regulations require a national average reduction of Carbon Dioxide Emissions of 30 % by 2030. The rule is actually 50 different rules, one for each state. And the mandate is not for any particular method to reduce emissions, just that they must be reduced.

Because Arkansas has above average reliance on coal fired power which emits the lion’s share of carbon, our required reduction amounts to 44 %. This may sound like a lot but remember we have 15 years to achieve this level of reduction.

Almost half this reduction can be achieved at little to no cost to the consumer. A study by the American Council for an Energy Efficient Economy found that nearly half that emission reduction can come about by increased energy efficiency. Whereas the reduced demand for power will mean a small loss of jobs as coal fired power plants close, many more jobs will be created for the necessary technology improvements to greater efficiency.

Wyoming coal

Wyoming coal

Generally the public is in agreement with the scientific community about threat of global warming. So how about the “ruling class?” Both the Republican and the Democrat, Asa Hutchinson and Mike Ross have spoken against the rule. Similarly an interim legislative committee, Insurance and Commerce, hase passed a resolution condemning the EPA rule as illegitimate. Cries of violation of “states rights” rang through the halls.

In reality the only serious argument is that clean air and a stable environment for the future MAY cost somewhat. Let it be noted that every regulatory action to clean our air and water has been met with cries that to do so will crash our economy. It hasn’t happened yet, not with removing lead from gasoline, nor with preventing acid rain, and now not with mitigating the risk of global warming.

So why the dire warnings from politicians? A 2014 study conducted by the Sierra Club and Oil Change International found that for every dollar the fossil fuel industry contributes to candidates, it reaps 59 dollars in subsidies. Follow the money.