Thursday, May 29, 2014

Buying a CSA Farm Share


 The harsh winter just devastated my garden, what the deer didn’t eat the freezing and thaw cycle did in. While trying to herd my contractor through the repairs on my home, I was overwhelmed by having to replant the garden. In April I was hanging around the extension office waiting for a meeting to begin, when Thomas Bolles the Environmental Educator for the Prince William Extension commented in sympathy that for many this year would be a lost year in the garden. I mulled it over all afternoon, finally embracing the idea that I only need to cleanup, replant the perennials and replace the lost trees. I would hire some professional help and buy a farm share. Done.

Jay Yankey in addition to being the Director of the Prince William Soil and Water Conservation District, runs Yankey Farms, a direct to consumer farming operation. In addition to his farm stands and pick your own berry and pumpkin patch he had in the past operated a community supported agricultural, CSA, program. This year he happened to be restarting the program and on that April afternoon still had a couple of farm shares to sell. A CSA or farm share from Yankey Farms is a 16 week subscription program where you receive a share of whatever produce is being harvested on the farm that week. Yankey Farms offers half bushel and full bushel shares. I bought a half bushel share, but it’s gone in 4 days. The CSA program had been successful and profitable for Yankey Farms; however last year in an attempt to streamline his farming operation he did not run the program. Fortunately for me, this year he jumped back in.

The produce from the farm share follows the planting and growing season. There are 4 weeks of spring produce then a couple-three weeks off before the summer harvest begins. The summer harvest lasts for about 6 weeks followed by another 2-3 week break before starting the fall harvest, which will lasts for another 6 weeks. The weekly share is picked up at the farm in Nokesville and if you arrive mid-afternoon this time of year you can see Jay’s Dad on a tractor out in the field. So far, the spring share has included strawberries, lettuce (all kinds), broccoli, cabbage, spring onions, cauliflower, kale, , and bok choi. I’m still hoping for cherries, summer squash, cucumbers, peas, beets, spinach, but that last snow and short spring might impact the crops.

In the summer we are promised peaches, tomatoes, onions, potatoes, green beans, peppers, eggplant, plums, melons, sweet corn, cucumbers, blueberries, blackberries, summer squash, and okra. While I’m not fond of okra and really how much bok choi do you want to eat (grill it brushed with olive oil and sea salt), I love Yankey Farm’s berries. For the fall they expect to have winter squash, cauliflower, sweet potatoes, pears, cabbage, collard greens, raspberries, broccoli, Brussels sprouts, apples, green beans, onions, and pumpkins. Yankey Farms CSA is not organic; I am very comfortable with Jay’s farming practices and the quality of the produce and fruit I get with my farm share.

Yankey Farms grows about 15-20 acres of produce and 50 acres of small grain based on a model of conservation agriculture, which is an integrated model of lest toxic, cost effective farming, utilizing crop rotation, field borders, cover crops and low till or no-till to reduce erosion. Yankey Farms leaves a permanent cover crop and drills through the upper layers to plant the seeds, always working to minimize erosion. Yankey Farms has about 5 acres of irrigation ponds used in a sustainable irrigation model. These ponds are filled by rainfall and are used to ensure that the crops get at least one and a half inches of rain a week. Though it varies from year to year depending on weather, the vegetable crops required 15,000 gallons per acre per week and the grains 40,000 gallons per acre per week.

Conservation agriculture uses herbicides (the least toxic) and active manipulation of organic matter in the soil to deal with weeds. No till farming, reduces sediment, nitrogen and phosphorus runoff that is responsible for contamination of our watershed, the Chesapeake Bay. Leaving the soil intact also increases its ability to hold onto carbon dioxide, which means less carbon dioxide is released into the atmosphere. Instead of plowing up the ground to plant the crops, Yankey Farms uses a machine that punches the seeds or plant into the ground. No till farming can reduce erosion up to 90%, and reduces reliance on fertilizers as compared to “conventional industrial” farming.

Organic farming requires that farmers till the land, churning up the crop land, pulling up weeds and mixing them into the soil and does not use chemical herbicides. Disturbing the soil cover, loosening it so it's no longer tightly packed, leaves it more susceptible to being washed away by rain and wind and potentially finding its way into streams and rivers. Conservation agriculture and organic farming both strive to achieve balance between people and the land so that the land can continue to feed people without damaging the earth. Conservation agriculture emphasizes sustainability of the farming operation and maintaining soil by minimizing soil disturbance, maintaining a permanent soil cover and utilizing crop rotations to retain soil nutrients. Conservation agriculture is a proven method of sustainable land management.

While buying a farm share limits your choice of produce, what you receive is wonderfully fresh and delicious. The broccoli and strawberries have been fantastic. Also, it is important to me to know my farmer and his practices-not only for the quality of his food, but also for his impact on the earth.

Monday, May 26, 2014

The Kemper Plant and Carbon Sequestration

from Mississippi Power
Last September the U.S. Environmental Protection Agency (EPA) revised their proposed Clean Air Act standards to cut carbon pollution from new power plants. Under the revised proposal, new coal-fired electrical generation turbines would need to meet a limit of 1,100 pounds of CO2 per megawatt-hour. Existing coal –fired electrical generation turbines emit about 2,080-2,180 pounds of CO2 per megawatt-hour of power produced. All existing plants would be grandfathered and exempt from this rule for a period of time, but the EPA was expected to propose CO2 limitations for existing power plants next month. Increased regulation on existing plants was to occur after demonstration of the commercial use of a kind of carbons capture and sequestration (CCS) technology called Transport Integrated Gasification (TRIG™) technology at a newly built power plant in Kemper County, Mississippi. This TRIG technology was developed by Southern Company (the parent of Mississippi Power) and KBR in conjunction with the Department of Energy (DOE).

TRIG is a coal-gasification method designed to be cleaner (capturing 65% of CO2), cheaper and to work with lower rank coals like the Mississippi Lignite. However, the construction of this new technology plant has been besieged with problems and cost and timing overruns as details such as pipe thickness and metallurgy were miscalculated in the initial design. Originally, the project was estimated to cost $2.4 billion to build the 582,000 kilowatts plant that translated to $4,123 per kilowatt (before DOE grants and tax credits). Now, however, the Kemper plant is projected to be delayed another year until May 2015 and to cost $5.5 billion or $9,450 per kilowatt, and the technology has not even been demonstrated to work on an industrial scale, yet.
from Mississippi Power


Mississippi Power, the smallest utility subsidiary of Southern Company, owns the plant and can only recover up to $3.8 billion for the Kemper costs through customer rates and the sale of securitized bonds. Customers began paying 22% higher utility rates for their power to Mississippi Power after the Kemper plant was allowed into the cost base last year after a lengthy regulatory battle. Meanwhile, Southern Company/ Mississippi Power has taken a $1,037,000,000 charge (so far) against earnings to write off costs overruns that cannot be recovered. The EPA has described carbon capture and sequestration as an available technology that will increase the capital cost of every new coal plant built in the United States by only 35%, but the cost overruns at Kemper have more than doubled the cost of the plant and brought the cost of building a coal fired electrical turbine to about nine times the cost of a gas fired turbine.

Regulating CO2 emissions from power plants are all part of the President’s Climate Action Plan that directs all federal agencies to address climate change using existing executive authorities. The EPA is the lead regulator of the plan to cut carbon pollution. The Plan has three key pillars: cutting carbon pollution in the United States; preparing the country for the impacts of climate change; and leading international efforts to combat global climate change. Power plants are the largest concentrated source of emissions in the United States, accounting for roughly one-third of all domestic greenhouse gas emissions. The Energy Information Agency (EIA) most recent preliminary data through March 2013 show coal has generated 40% or more of the nation's electricity each month since November 2012, with natural gas fueling about 25% of generation during the same period. In 2012 natural gas had accounted for a larger share of power generation than in 2013, but fuel costs and power demand during the recent harsh winter increased the power generated by coal fired power plants.
from EIA
The Kemper plant will not be abandoned; it will be completed and will be operated. Southern Company or Mississippi Power, the operating subsidiary, (and possibly bond holders) will have to write off an additional $700 million or more, but the Kemper plant once it’s completed and running will have operational cost advantages. The plant is adjacent to a new coal mine with over 4 billion tons of lignite and near to old Mississippi oil fields. Lignite coal after drying out for three days is fine for the type of plant Southern is building and can supply the plant for centuries. The old oil fields offer an opportunity to sell the CO2 for enhanced oil recovery. Kemper’s pressurized and liquefied carbon dioxide will be used to enhance oil recovery and is estimated to increase oil production by 2 million barrels a year. Liquefied CO2 is valued at around $40 a ton right now and Kemper is projected to capture about 3-3.5 million tons a year.

The Kemper plant when it is finally completed will have a base coal-fired capacity of 524,000 kilowatts and natural gas capacity 58,000 kilowatts. The plant will capture 65% of total CO2 emissions resulting in 3-3.5 million tons per year of captured CO2 and reducing the CO2 emissions per megawatt to under 800 pounds if the plant performs as designed. The Kemper plant will also have fewer particulate, sulfur dioxide and mercury emissions than traditional pulverized coal plants making it the cleanest coal plant ever built.

The utility rate payers and shareholder will both share in the high cost of this project. You and I threw in a little bit, too. Mississippi Power received a $270 million grant from the Department of Energy for the project and $133 million in investment tax credits approved by the Internal Revenue Service. Although by missing its projected deadline it will loses some of the tax benefits.
from Mississippi Power


Thursday, May 22, 2014

World Carbon Emissions


Recently, President Obama has been focusing on climate change. So, I decided to take a look at the “Trends in Global Emissions 2013 Report” the latest report from the Netherlands Environmental Assessment Agency and the European Commission’s Joint Research Centre (JRC). Using data collected from various sources and the computer model called EDGAR (Emission Database for Global Atmospheric Research) they compile the world estimates of CO2 emissions data.

In 2012, total world emissions of CO2 increased by 1.4% (corrected for leap year it was 1.1%) over 2011, to reach a total of 34.5 billion tonnes of CO2. In 2012 the top five world generators of CO2 emission from fossil fuels were (once again) in descending order China, the United States, the European Union, India and the Russian Federation.

The rate of increase in CO2 emissions has slowed. The average annual increase in world CO2 emissions was 2.9% per year since 2000. This growth was driven primarily by the growth in China, India and other developing countries as those economies emerged. India’s GDP growth at around 4% in 2012 was the lowest in a decade. India’s CO2 emissions in 2012 continued to increase by 6.8% to about 2.0 billion tonnes. China with the largest population is the largest CO2 emitter on earth. They increased CO2 emissions by 3% in 2012, compared to an average rate of increase in CO2 emissions of around 10% per year during the last decade.


In the United States CO2 emissions decreased by 4% in 2012. The United States which represents 16% of total world emissions has decreased total CO2 emissions each year since 2005. In 2012, with GDP (gross domestic product) growth of 2%, their CO2 emissions decreased by 4%, mainly because of a fuel shift from coal to gas in the power generation. Natural gas produces about half the CO2 as coal for the same amount of electricity. In recent years, the United States expanded shale gas fracturing and has now become the largest natural gas producer in the world.

In the European Union CO2 emissions decreased 1.6% in 2012. The European Union, as a whole, was in a recession in 2012. The European Union’s GDP declined by 0.3%, compared to 2011, and CO2 emissions declined by 1.3%. The European Union reported a decrease in consumption of oil and gas, by 4% and 2% respectively, a decrease in freight transported of 4%, and a decrease of 2% in total emissions from power generation and manufacturing installations. However, the use of coal for power generation increased in the European Union in 2012. Relative pricing for coal and gas and a decrease in the use of nuclear energy to generate power in the aftermath of the Fukushima accident are responsible for the increase in coal use in other parts of the world.

Renewable energy power generation has increased worldwide. The use of hydropower has accelerated and its output increased by 4.3%, between 2011 and 2012. The share of the ‘new’ renewable energy from solar, wind and biofuel also increased to 2.4% in 2012. In 2012 there appeared to be a ‘decoupling’ of the increase in CO2 emissions from global GDP growth. This may be an anomaly or indicate a shift towards less fossil-fuel intensive activities or fuel switch to less CO2 intense fuels, more use of renewable energy and increased energy saving.

Nonetheless, the worldwide level of CO2 emissions is higher than the worst-case scenario outlined by climate experts just six years ago, but fortunately temperatures have not (yet) risen as projected by the climate models. The relationship of climate change to worldwide CO2 levels may not be the one previously assumed as research continues and time lags and other factors are studied and climate prediction models are modified to reflect ongoing research. The developed world no longer drives or controls CO2 emissions, and there is little we can do to change the future. What is going to happen will happen. Though we should still strive to reduce our personal energy use and efficiency.

Monday, May 19, 2014

Oil Imports from Canada Continue to Grow

In mid-April 2014 the U.S. Department of State announced that it will delay with no definite period of time cited a decision on the Keystone XL Pipeline. At this point it seems unlikely that any decision will be made in 2014 and unlikely that this pipeline and route will obtain a Presidential permit from this Administration. Though the Keystone XL pipeline seems to have become a symbol to protestors, in truth Keystone XL is unlikely to impact the rate of extraction of the Canadian oil sands or the demand for heavy crude oil at the six Gulf coast refineries. No matter what action the Administration chooses to take on this portion of the pipeline-approve, reject, or stall- the oil sands are not staying in the ground in Canada. There is world demand for heavy crude oil and it will be met. The Texas refineries are optimized for heavy crude either from South America or Canada. The crude oil will come by pipeline, boat, truck or rail road.

As you can see in the charts below Canadian imports of oil continue to grow while overall U.S. oil imports (and consumption) have fallen. According to the U.S Energy Information Administration total U.S. consumption of petroleum products has fallen 11% since 2007 to 6.748 billion barrels a year. Imports of petroleum products fell by almost 21% over the same period with the difference made up by domestic oil production. In addition, between 20012 and 2013 petroleum imports fell by an additional 7.5%. Overall, as a nation, we are using less petroleum products and producing more of what we use.

Canadian crude is flowing into the United States by truck, rail and pipeline. Back in July 2013 the Minnesota Public Utilities Commission approved plans for Enbridge Energy to increase the capacity of the United States portion of their Line 67 (formerly the Alberta Clipper Pipeline) in Minnesota. Though construction is to be completed on this Phase I expansion in July 2014 Enbridge still requires a Presidential Permit to expand their oil shipment across the U.S.-Canadian border and the US State Department is conducting an environmental review of the expansion plan potentially delaying or stalling the pipeline project. This request differs from the Keystone XL request because the pipeline in question is already in place and the request is to increase the capacity by upgrading the pumping stations.

Oil sands production and development will slow or accelerate depending on oil price trends, regulations, and technological developments. The Canadian oil sands have been known for decades, but until oil prices rose and technology improved these oil deposits were too expensive to exploit beyond the limited scope of surface mining. Advances in technology in both oil sand extraction and refining techniques and rising oil prices altered the economics and have made the extraction of oil sand possible. While the advances in extraction techniques have quadrupled recoverable oil reserves and moved Canada into second place in proved world oil reserves, it requires more energy to produce the oil and increases the carbon footprint of the crude as compared to fracked light sweet crude from Texas or Montana. I believe that opponents to the pipeline projects object primarily on concerns for increasing greenhouse gases in the environment. Opponents contend that extracting Canada’s heavy crude oil releases between 10-17% more greenhouse gases than conventionally extracted oil. I have not reviewed the studies that are the basis of that claim so I hold no opinion.

Nonetheless, the Canadian oil is flowing into the U.S. and the Oklahoma to Texas Seaway pipeline that opened in January completing the crude oil pipeline from Canada to the Gulf Coast and has alleviated the bottleneck in Oklahoma. Canadian crude prices have recovered from their depressed levels last year and Canadian imports continue to increase.

Thursday, May 15, 2014

What's in the Water Wells of Prince William County

The Virginia Cooperative Extension (VCE) Offices in Virginia occasionally holds drinking water clinics for well, spring and cistern owners as part of the Virginia Household Water Quality Program. The VCE subsidizes the analysis cost for these clinics. Currently, samples are analyzed for: iron, manganese, nitrate, lead, arsenic, fluoride, sulfate, pH, total dissolved solids, hardness, sodium, copper, total coliform bacteria and E. Coli bacteria at a cost of $49 to the well owner. This is far from an exhaustive list of potential contaminants, but with one or two exceptions these are the most common contaminants that effect drinking water wells. These are mostly the naturally occurring contaminants and common sources of contamination: a poorly sealed well or a nearby leaking septic system, or indications of plumbing system corrosion. The above chart shows what we found in the private wells tested in Prince William County in 2014.

There are other contaminants that have be found in groundwater in many parts of the country, but this clinic only tested for the most common water quality problems in Prince William County and Virginia. There are also nuisance contaminants which are fairly common, but lack an approved EPA methodology for testing, iron bacteria is an example. Wells should be tested annually for bacteria and every 1-3 years for other common contaminants and at least once have a full analysis . If you install a treatment system to address a problem, testing should be more frequent. Groundwater is dynamic and can change over time, and it is important to make sure that any treatment is still appropriate and effective. Water treatment systems are not an install and forget piece of equipment, they are more systems to maintain, adjust and control to keep the water within ideal parameters. Improperly treated water can be as problematic as not treating water.

In order to determine if treatment is necessary, water test results should be compared to a standard. The standard we use is the U.S.EPA Safe Drinking Water Act , SDW, though that regulation does not apply to private well owners. The SDW act has primary and secondary drinking water standards. Primary standards are ones that can impact health and from the our tested substances include: coliform bacteria, E. coli bacteria, nitrate, lead, and arsenic.

The 2014 Prince William County water clinic, like most of the clinics in the Virginia Rural Household Water Quality Program, found that a third of the wells tested found coliform bacteria present in the water samples. Coliform bacteria are not a health threat itself, it is used to indicate other bacteria that may be present and identify that a well is not properly sealed from surface bacteria. The federal standard for coliform bacteria is zero, but the federal standard allows that up to 5% of samples can test positive for coliform during a month. Fecal coliform and E. coli are bacteria whose presence indicates that the water is contaminated with human or animal wastes. Disease-causing microbes (pathogens) in these wastes can cause diarrhea, cramps, nausea, headaches, or other symptoms. These pathogens may pose a special health risk for infants, young children, and those with compromised immune systems. However, people can drink water contaminated with fecal bacteria and not notice. If your water is contaminated with coliform but not fecal coliform or E. coli, then you have a nuisance bacteria problem and the source may be infiltration from the surface from rain or snow melt. Typical causes are improperly sealed well cap, failed grouting or surface drainage to the well. Shock chlorinate the well, repack the soil around the well pipe to flow away from the well and replace the well cap. Then after the next big rainstorm retest the well for coliform. If it is still present then a long-term treatment should be implemented: using UV light, ozonation, or chlorine for continuous disinfection.

If you have fecal coliform in the well or E. coli, your well is being impacted by human or animal waste and you are drinking dilute sewage. If there is not a nearby animal waste composting facility, then you are probably drinking water from a failed septic system- yours or your nearest neighbors. To solve this problem you need to either fix or replace the septic system that is causing the contamination, replace the well or install a disinfection and filtration system. Disinfection does not kill Giardia or Cryptosporidium, two microscopic parasites that can be found in groundwater that has been impacted by surface water or sewage. Both parasites produce cysts that cause illness and sometimes death.

Membrane filtration is the usual treatment for these parasites- a one micron membrane is required after disinfection and can be accomplished at home with a reverse osmosis system. The failing septic systems can often be identified by using tracer dyes. While continuous disinfection will work to protect you from fecal bacteria and E. coli, be aware that if your well is being impacted by a septic system, then the well water might also have present traces of all the chemicals and substances that get poured down the drain. Long term treatment for disinfection, and micro-filtration should be implemented: using UV light, ozonation, or chlorine for continuous disinfection, carbon filtration, and anything that is used for drinking should be further treated with a reverse osmosis systems or micro membrane system that work by using pressure to force water through a semi-permeable membrane. Large quantities of wastewater are produced by reverse osmosis systems and need to bypass the septic system or they will overwhelm that system creating more groundwater problems. Reverse osmosis systems produce water very slowly, a pressurized storage tank and special faucet needs to be installed so that water is available to meet the demand for drinking and cooking.

Nitrate can contaminate well water from fertilizer use; leaking from septic tanks, sewage and erosion of natural deposits. Only one well in our group had nitrate levels above the MCL. The MCL for nitrate is 10 mg/L the one well that tested above that level tested at 10.5 mg/L. Infants below the age of six months who drink water containing nitrate in excess of the MCL could become seriously ill from blue-baby syndrome and, if untreated, may die. Symptoms include shortness of breath and a blue ting to the skin common in blue-baby syndrome. The NO3 dissolves and moves easily through soil which varies seasonally and over time as plants use up the nitrate over the summer. Testing in the spring will usually produce the highest levels. Nitrate may indicate contamination from septic tanks, but do not boil the water- boiling water reduces the water and actually INCREASES the concentration of nitrates. Reverse osmosis, or ion exchange is necessary to control the nitrate.

Iron and manganese are naturally occurring elements commonly found in groundwater in this part of the country. Several of the wells tested exceeded the secondary standard, 5.1% of the wells tested exceed the iron standard and 7.7% exceeded the manganese standard. At naturally occurring levels iron and manganese do not present a health hazard. However, their presence in well water can cause unpleasant taste, staining and accumulation of mineral solids that can clog water treatment equipment and plumbing. The standard Secondary Maximum Contaminant Level (SMCL) for iron is 0.3 milligrams per liter (mg/L or ppm) and 0.05 mg/L for manganese. This level of iron and manganese are easily detected by taste, smell or appearance. In addition, some types of bacteria react with soluble forms of iron and manganese and form persistent bacterial contamination in a well, water system and any treatment systems. These organisms change the iron and manganese from a soluble form into a less soluble form, thus causing precipitation and accumulation of black or reddish brown gelatinous material (slime). Masses of mucous, iron, and/or manganese can clog plumbing and water treatment equipment.

All systems of removing iron and manganese essentially involve oxidation of the soluble form or killing and removal of the iron bacteria. When the total combined iron and manganese concentration is less than 15 mg/l, an oxidizing filter is the recommended solution. An oxidizing filter supplies oxygen to convert ferrous iron into a solid form which can be filtered out of the water. Higher concentrations of iron and manganese can be treated with an aeration and filtration system. This system is not effective on water with iron/ manganese bacteria, but is very effective on soluble iron and manganese. Chemical oxidation can be used to remove high levels of dissolved or oxidized iron and manganese as well as treat the presence of iron/manganese (or even sulfur) bacteria. The system consists of a small pump that puts an oxidizing agent into the water before the pressure tank. The water will need about 20 minutes for oxidation to take place so treating before a holding tank or pressure tank is a must. After the solid particles have formed the water is filtered. The best oxidizing agents are chlorine or hydrogen peroxide. If chlorine is used, an activated carbon filter is often used to finish the water and remove the chlorine taste. The holding tank or pressure tank will have to be cleaned regularly to remove any settled particles.

The pH of water is a measure of the acidity or alkalinity. The pH is a logarithmic scale from 0 – 14 with 1 being very acidic and 14 very alkaline. Drinking water should be between 6.5 and 7.5. For reference and to put this into perspective, coffee has a pH of around 5 and salt water has a pH of around 9. Corrosive water, sometimes also called aggressive water is typically water with a low pH. (Alkaline water can also be corrosive.) Low pH water can corrode metal plumbing fixtures causing lead and copper to leach into the water and causing pitting and leaks in the plumbing system. The presence of lead or copper in water is most commonly leaching from the plumbing system rather than the groundwater. Acidic water is easily treated using an acid neutralizing filter. Typically these neutralizing filters use a granular marble, calcium carbonate or lime. If the water is very acidic a mixing tank using soda ash, sodium carbonate or sodium hydroxide can be used. The acid neutralizing filters will increase the hardness of the water because of the addition of calcium carbonate. The sodium based systems will increase the salt content in the water. Though 20.5% of the wells tested were found to have acidic water, only one well tested had a pH above 8.5 and that well also had high levels of sodium. The well owner emailed me with that information because I had stated in the clinic that high pH and elevated sodium levels were possible indications of salt water intrusion.

Water that contains high levels of dissolved minerals is commonly referred to as hard. Groundwater very slowly wears away at the rocks and minerals picking up small amounts of calcium and magnesium ions. Water containing approximately 125 mg/L can begin to have a noticeable impact and is considered hard. Concentration above 180 mg/L are considered very hard. As the mineral level climbs, bath soap combines with the minerals and forms a pasty scum that accumulates on bathtubs and sinks. You either must use more soap and detergent in washing or use specially formulated hard water soap solutions. Hard water can be just a minor annoyance with spotting and the buildup of lime scale, but once water reaches the very hard level 180 mg/L or 10.5 grains per gallon, it can become problematic, 18% of the wells had hard water exceeding that level. Hard water spots appear on everything that is washed in and around the home from dishes and silverware to the floor tiles and cars. When heated calcium carbonate and magnesium carbonate are removed from the water and form a scale (lime scale) in cookware, hot water pipes, and water heaters.

Water softening systems are used to address the problem are basically an ion exchange system. The water softening system consists of a mineral tank and a brine tank. The water supply pipe is connected to the mineral tank so that water coming into the house must pass through the tank before it can be used. The mineral tank holds small beads of resin that have a negative electrical charge. The calcium and magnesium ions are positively charged and are attracted to the negatively charged beads. This attraction makes the minerals stick to the beads as the hard water passes through the mineral tank. Sodium is often used to charge the resin beads. As the water is softened, the sodium ions are replaced and small quantities of sodium are released into the softened water, thus the salty taste of softened water. When the water softening system is recharged the excess sodium solution carrying the calcium and magnesium is flushed to the septic system which may shorten the life of the drain field.

At the present time the EPA guidance level for sodium in drinking water is 20 mg/L. This level was developed for those restricted to a total sodium intake of 500 mg/day and does not necessarily represent a necessary level for the rest of the population. Based on taste of the water levels of sodium should be below 30 to 60 mg/L based on individual taste. Water softening systems add sodium. Reverse osmosis systems and distillation systems remove sodium and are safe for household use, but addressing hard water by using vinegar to descale pots and dishwashers, regularly draining hot water heaters, and using detergents formulated for hard water might be a better solution for you.

Monday, May 12, 2014

New Solar Panels for the White House

Last Friday, the Obama Administration finally installed the long promised solar panels on the roof of the residential section of the White House timed to correspond with the President’s Climate Action push. At the time of the installation the President was in California laying out a list of clean energy objectives he can accomplish without congress. The White House has not specified how many panels they installed or how much they cost, but reportedly, the solar installations on the White House is the size of the “typical” residential installation and will pay for itself in energy savings and Solar Renewable Energy Certificates, SRECs, in eight years. I do not know if the White House installation qualified for a federal tax credit.

At today’s costs solar panels can have a payback of eight years only with the “help” of tax rebates and Solar Renewable Energy Certificates, SRECs, which are available to residents of Washington DC and a few other states. Currently, SRECs in Washington DC are the most valuable in the nation, but it is an artificial market that will fall as more solar systems are installed and the price supports are decreased in the next few years. If you live in the District you can see what the cost and return of a solar system on your building’s roof top would be using the Mapdwell Project mapper. This assumes the SREC market remains viable. The solar system size used is based on the size of the roof and is effectively the maximum size solar array you could install. You of course could install a smaller array. To those of you not old enough to remember, this is the second time that solar panels have been installed on the White House. President Jimmy Carter spent $30,000 on a solar water-heating system for West Wing offices in the late 1970's that were subsequently removed by President Ronald Reagan.

As I watched the U-tube video of the White House installation I was a little envious of how smoothly it all seemed to go. This was not the case with my installation. On the back of my house is a roof mounted 7.36 KW solar array consisting of 32 Sharp 230 watt solar photovoltaic panels and 32 Enphase micro-inverters, somewhat larger than the “typical” home installation, but not much larger than what I imagine the White House installed. When I purchased my solar panels I choose the Enphase micro inverter system so the power cables running down the side of my house, albeit inside a pipe, are 120 current instead of 240 and the energy production of each individual panel can be checked on the internet. The solar array consists of panels the racks that hold them, micro inverters and wiring and plugs. My installation did not go smoothly, and surprisingly to me, maintenance has turned out to be an issue.

I check my solar panels production numbers every month when I get my power bill. I am on net metering with my power cooperative to sell my SRECs into the Washington DC SREC market where my system was grandfathered when it was closed to out of city systems. My installation web page allows me to see the current energy produced by each of my 32 panels every minute, every hour, daily, weekly, monthly and the cumulative total power output. I only spot check the solar panel midday on the day when my power bill arrives or after storms to make sure all the panels are performing optimally. The reason I chose Enphase was to be able to easily identify a problem with the system. Little did I know that barely three years after the installation I would be facing repair issues.
my solar array with the failed panels
About 14 months ago, less than three years into their expected 25-year life span, one of my solar panels appeared to fail. My first attempt to have my system repaired was emails, letters and phone calls to the company that installed my system. The company I hired to install the system was no longer in the solar business- without renewable energy rebates and a viable solar renewable energy certificate market; there was not enough business to sustain a solar installation operation in Virginia. They were focusing instead on energy audits, but they finally referred me to a Maryland and Washington DC based installer, Lighthouse Solar.

It took a while for them to come out. They looked into my system and spoke to Enphase and determined that the problem was probably the micro inverter so they ordered a new inverter from Enphase. By the time they had scheduled my repair a second inverter had failed. I was delighted when they were able to replace both inverters on the same day. According to Lighthouse Solar, they have replaced many Enphase inverters. The good news is that the inverters had a 10 year warrantee and it cost me nothing. The bad news is that the new inverters did not fix the problem, though for a brief period of time it appeared to fix one of the two panels. After some back and forth between Enphase, Lighthouse Solar and me, I appeared to have a solar panel failure. Sharp was not as cooperative as Enphase with replacing the panels which were guaranteed for 25 years.

Ultimately, I think that the original installer paid for a new panel and when this spring arrived, Lighthouse Solar made a second attempt at repairing the system and replaced a solar panel. Once more Lighthouse Solar came through for me and got the repair done at no cost to me. Unfortunately, after replacing the solar panel I now have one failed panel and one panel working at partial capacity. After speaking once more to Enphase Energy, Lighthouse Solar now says that they will try new inverters. There are a limited number of components that could have failed, but unfortunately since Lighthouse Solar has to fight to obtain each component for me under warrantee, they have been unable to simply replace everything at once and get the problem solved. The actual cost of buying and replacing all the potentially failed portions of the system would cost more than a year’s worth of power production of the entire system.

All solar PV panels degrade and slowly over time produce less power, however based on news report there appears to be a cluster of failures after a couple three years. Solar photovoltaic panels have no moving parts so that the operating life of the solar panels is largely determined by the stability of the coating film, the quality of finish and fit of the panels and the proper sealing of the edging and connectors. Quality control in manufacturing is essential to have a solar panel that wills last 25 years in sun, rain, sleet and snow. The quality and life span of these rapidly produced solar panels is about to be tested in the next few years.

Without micro inverters a failure of one panel in an array like mine is a 3% reduction in power production and might not be noticed, it could be attributed to decreasing efficiency of the panels or weather variations. In Ed Begley, Jr.’s “Guide to Sustainable Living,” he said that over the years he had four solar panels fail, his storage batteries were replaced after 15 years and the wiring for the panels were damaged and needed to be replaced at 18 years. So, these systems are not trouble free even in sunny warm California, you cannot just install them and forget it. The President is only going to be living with the White House solar array for less than three years so he will not have to worry about maintenance, but as a nation we need to maintain our clean energy infrastructure. In my calculations of cost and return I was conservative on SREC value, but I did not consider maintenance costs or loss of power production due to equipment failure. I am on net metering and still connected to the grid so I continue to get all the power I need from the grid. I have spent a lot of time and effort on trying to get my solar panel array repaired without yet succeeding. Nothing magically maintains itself, consider maintenance and repairs whenever buying equipment.
map dwell example of cost and return

Thursday, May 8, 2014

E. coli in Your Water What Are Your Options

If your water comes from a well, you need, at a minimum, to test your well each year for bacteria. Even if you have a treatment system in place you need to test to make sure the water you drink, brush your teeth with and cook with is safe.  Though human senses cannot detect many contaminants, if you detect a change in the appearance, taste or smell of your water, test it immediately. If you (or your spouse) become pregnant you should test the water. I you have a new infant in the house you should test the water. A bacteria test is the most basic test to see if your water is potable, if your well tests positive for any bacteria, it is an indication that your well is being impacted by either surface contamination, an animal compost or a failing septic system and you need to do further testing.

Coliform bacteria are not a health threat itself, it is used to indicate other bacteria that may be present and identify that a well is not properly sealed from surface bacteria. The federal standard for coliform bacteria for public drinking water supplies has been recently revised to reflect this, requiring public water suppliers to conduct an assessment to determine if any sanitary defects exist and correct them.  Fecal coliform and E. coli are bacteria whose presence indicates that the water is contaminated with human or animal wastes or as we like to call it in our house, poopy water. Disease-causing microbes (pathogens) in these wastes can cause diarrhea, cramps, nausea, headaches, or other symptoms. These pathogens may pose a special health risk for infants, young children, and those with compromised immune systems. However, people can drink water contaminated with fecal bacteria and not notice.

 If your water is contaminated with coliform but not fecal coliform or E. coli, then you have a nuisance bacteria problem and the source may be infiltration from the surface from rain or snow melt. Typical causes are improperly sealed well cap, failed grouting or surface drainage to the well. Shock chlorinate the well, repack the soil around the well pipe to flow away from the well and replace the well cap. Then after the next big rainstorm retest the well for coliform.  If coliform bacteria are still present then a long-term treatment should be implemented: using UV light, ozonation (less available for home use), or chlorine for continuous disinfection.

If you have fecal coliform in the well or E. coli, your well is being impacted by human or animal waste. If there is not a nearby animal waste composting facility, then you are probably drinking water from a failed septic system- yours or your nearest neighbors. To solve this problem you need to fix or replace the septic system that is causing the contamination, replace the well or implement and properly maintain the right water treatment system. The failing septic systems can often be identified by using tracer dyes. Ideally, you should identify and repair the failing septic system. If it is not your system, you will have to work with the Department of Health and your neighbors to address this problem and it will take time. Even if a failing septic system is repaired, it can take days or years for the contaminated water to dissipate.

In the meantime, you need to treat your water.  Do not be grossed out by the thought of treating and then drinking what is essentially diluted and partially treated waste water. All the water that ever was or will be on earth is here right now. It is not being created or destroyed. The water on earth never rests, it is constantly moving within the hydrologic cycle along various complex pathways and over a wide variety of time scales, days, years, decades, centuries, or more. Even in generally water rich areas there are limits to the availability of water and United States has slowly and quietly begun to address the availability of water by recycling the water. Direct water recycling, using treated wastewater for beneficial purposes such as agricultural and landscape irrigation, industrial processes, toilet flushing, and replenishing a ground water basin (referred to as ground water recharge) and less commonly returning the water directly to reservoirs is expanding. Since 1978, the upper Occoquan Sewage Authority has been discharging recycled water into a stream above Occoquan Reservoir that flows right into the reservoir, one of the two potable water supply sources for Fairfax County, Virginia. Recycled water has been part of the Occoquan supply for 34 years and chances are if you lived or worked in Fairfax, parts of Prince William and Loudoun counties you have been regularly drinking recycled water.

While continuous disinfection will work to protect you from fecal bacteria and E. coli, be aware that if your well is being impacted by a septic system, then the well water might also have present traces of all the chemicals and substances that get poured down the drain. In addition, ultra violet or chlorine disinfection does not kill Giardia or Cryptosporidium, two microscopic parasites that can be found in surface water and groundwater that has been impacted by surface water or sewage. Both parasites produce cysts that cause illness and sometimes death. Giardia are often found in human, beaver, muskrat, and dog feces. Cattle feces appear to be the primary source of Cryptosporidium, although these parasites have also been found in humans and other animals. Membrane filtration is the usual treatment for these parasites- a one micron membrane is required and can be accomplished at home with a reverse osmosis system. 

Long term treatment for disinfection, and micro-filtration using reverse osmosis should be implemented to address E coli or fecal coliform contamination:  using UV light, ozonation, or chlorine for continuous disinfection, carbon filtration, and anything that is used for drinking should be further treated with a reverse osmosis systems or micro membrane system that work by using pressure to force water through a semi-permeable membrane. Large quantities of wastewater are produced by reverse osmosis systems and need to bypass the septic system or they will overwhelm that system creating more groundwater problems. Reverse osmosis systems produce water very slowly, a pressurized storage tank and special faucet needs to be installed so that water is available to meet the demand for drinking and cooking.

Nitrate can contaminate well water from fertilizer use and erosion of natural deposits but also is a contaminant from human waste and rising nitrate levels are sometimes seen before E. coli contamination.  The MCL for nitrate is 10 mg/L. Infants below the age of six months who drink water containing nitrate in excess of the MCL could become seriously ill from blue-baby syndrome and, if untreated, may die. Symptoms include shortness of breath and a blue ting to the skin common in blue-baby syndrome. The NO3 dissolves and moves easily through soil which varies seasonally and over time as plants use up the nitrate over the summer. Testing in the spring will usually produce the highest levels. Nitrate is associated with contamination from septic tanks, but do not boil the water- boiling water reduces the water and actually INCREASES the concentration of nitrates. So if your water is being impacted by a septic system, you need to treat the water to remove the nitrate. Disinfection does not treat for nitrate. The appropriate treatment is for nitrate is; distillation, reverse osmosis, or ion exchange. Generally speaking, I would recommend staying away from iron exchange (water softeners) they can create as many problems as they solve and they are very expensive. Though there are situations where softening the water is really necessary do not do it as a default, softened water is believed to shorten the life of septic leach fields and cause the clogging of piping (though only limited research exists).

To properly treat well water that has been impacted by E. coli or fecal contamination, you need to disinfect the water using either a UV light or continuous chlorination. Your choice of systems should be based on personal preference and what other contaminants are present in your water. Both UV light and continuous chlorination do a good job of killing coliform bacteria including fecal coliform and E coli. However, chlorine treatment will control nuisance organisms such as iron, manganese, iron and manganese reducing bacteria and sulfate-reducing bacteria. Chlorine in water at the concentrations used for treatment is not poisonous to humans or animals. However, chlorine can impact the smell and/or taste of water even in very low concentrations. Household chlorination systems often use higher chlorine concentration than the typical 0.3 - 0.5 ppm (parts per million) concentration used for chlorination of public water supplies because the contact time is much shorter in home systems.

The typical home system uses 1-2 ppm. This elevated level of chlorine can result in the swimming pool smell and can impact the taste of food and my beloved cup of coffee. This smell can be removed using an activated carbon or charcoal filter. Trihalomethanes (THMs) are organic chemicals that may form when chlorine is used to treat water supplies that contain humic compounds. This is often the concern in large water systems that use surface water for their supply. Humic compounds form as a part of the decomposition of organic materials such as leaves, grass, wood or animal wastes. Because THMs are very seldom associated with groundwater, they are primarily a concern where surface water supplies are used. THMs can be removed from drinking water through use of an activated carbon filter. 

When installing a continuous chlorination system a chemical feed pump chlorinator is installed before the pressure tank in the basement and wired to water pump pressure switch. A fixed amount of chlorine solution is delivered with each pump discharge stroke. The chlorination system should be tested for free chlorine with test strips to adjust the dose. When the filter is in line the residual free chlorine should be under 1 ppm. You adjust the amount of chlorine by changing the length of the discharge stroke, the speed of the pump, or the running time of the pump to optimize performance of the system. Keeping a supply of good chlorine test strips and monitoring your water will allow you to optimize your system.

A contact tank for additional contact time, and a carbon media filter, for de-chlorination and removal of precipitated contaminants should be installed after the pressure tank. It might be necessary to install a larger pressure tank since to operate optimally a garnet media filter typically requires 50 pounds of pressure and small pressure tanks typically operate in 40-60 pound range. A larger pressure tank might eliminate the need for a contact tank, but be aware that the rubberized bladder can be oxidized by the chlorine over time. If you are removing large quantities of particulates from oxidized iron, manganese and sulfate a media filter that uses a graded from coarse to fine media to trap the suspended particles is necessary followed by activated carbon will deliver the best tasting water. Monitoring chlorine levels in the finished water (at the tap) assures you a supply of disinfected, water free from iron and manganese staining and hydrogen sulfide.

A UV light does not require a contact tank to kill bacteria, but since your water is being contaminated by septic waste, you might want also to have a carbon filtration system or a media filter followed by activated carbon to remove other impurities. The activated carbon filtration system will not remove iron or manganese, but can remove volatile organic chemicals, certain pesticide residues, radon, and odor and taste problems other than hydrogen sulfide (the rotten egg smell). Both disinfections systems require that you have a reverse osmosis system with a one micron membrane for removal of Giardia or Cryptosporidium. Remember that your reverse osmosis system should by-pass the septic system for its waste water discharge. A final note that very hard water will quickly clog the membrane in a reverse osmosis system. Water softeners are often recommended to solve this problem, but more frequent flushing and membrane replacement can also solve the problem. A water softener alone can cost almost $4,000 to install.  

Remember that a water treatment system in the home needs to be maintained and monitored continually. In the March 2012 Good Housekeeping magazine they evaluated home water testing kits. To test the home contaminant-detection kits, the Good Housekeeping Research Institute worked with the Water Sciences Laboratory at the University of Nebraska at Lincoln. Lab researchers spiked water samples with measured concentrations of contaminants the kits claimed to be able to detect, including two herbicides, nitrate, copper, lead, and bacteria. Then after following the kit's instructions, evaluated its performance at detecting the known contaminants. They found the PurTest kit to be the most accurate and easiest to use, but the second ranked First Alert test kit and was also good and significantly cheaper. These kits can be a good way to monitor the effectiveness or your water treatment system on an ongoing basis. 

Monday, May 5, 2014

The Rural Crescent

The long awaited “Prince William County Rural Preservation Study Report” was posted on the Department of Planning web site. I treasure the quiet and rural character of my home and I am a strong supporter for maintaining the Rural Crescent for ecological and water quality reasons as well as for quality of life for the entire community, so I was anxious to read the report. I attended a couple of the community outreach meeting and was left discouraged by the challenges that we face.

When the County Supervisors created the Rural Crescent in 1998 they slowed the loss of rural land in Prince William County. Limiting development density to one house per 10 acres combined with the limit on sewer extensions, creating one of the most protective zonings in Virginia, was a first step to preserve agricultural land. However, according to the consultants and based on the experience of the past 16 years, unless the zoning is very protective (one home per 30 to 50 acres, zoning alone will not preserve agriculture in the county and we are doomed to see the Rural Crescent cut up into 10 acre lots.

The Prince William County Rural Preservation Study found a broad support among stakeholders (community groups and residents) that it is important to maintain a Rural Area within the County. Another point of general consensus was that current preservation policies (primarily 10-acre zoning) is a one-size fits all approach that is not working very well across the large Rural Crescent area, which varies greatly in character from one end to the other. More tools are needed in the County’s Rural Crescent preservation toolbox to preserve a rural area. Furthermore, the consultants argue that mindful use of a series of tools can advance both Rural Crescent preservation areas and development goals.

According to the consultants, the County has a narrow window of opportunity to develop additional programs to maintain the character of the Rural Crescent. The 20,000 to 30,000-acre pool of farmland is fairly small and has been shrinking. Subdivision of the remaining farmland continues. The Study makes a series of recommendations that the consultants believe if fully adopted would result in a net increase of approximately 1,150 houses in the Rural Crescent and an increase of approximately 10,700 acres of permanently preserved land.

This 10,700 acres is far less than the County’s master plan stated goal of 39% protected open space, but almost 39,000 additional acres would be needed to meet that goal, and the pool of land still available to achieve this is less than 30,000 acres. Without policy changes, the Rural Crescent will likely continue to develop dominated by large lot residential development, with little contiguous open space and significant loss of agricultural lands, losing the open space for the county and the rural character of the area. So, the consultants recommend that the Supervisors adopt within the Comprehensive Plan a vision that describes what the County wants the Rural Area to be and use that vision as the basis for setting policy. They suggest:

“The Rural Area is a landscape dominated by agriculture, woodland, open space and other undeveloped land. The Rural Area allows for low-density residential development that is planned and designed to not dominate the landscape. The Rural Area accommodates a variety of activities and lifestyles associated with rural areas including farming of all types, low density residential living, rural businesses, cultural heritage, recreation, and preservation and enjoyment of the natural environment.”

The more I thought about it, the more I liked that vision for the Rural Crescent (which the consultants always call the “Rural Area.”) The consultants go on to recommend that each development proposal should be reviewed on a case by case basis to consider whether it would further the vision and policies for the Rural Area and limiting maximum gross density of one unit per two to three acres and a minimum 50 % open space requirement.

Tools that the County needs to develop for maintaining the Rural Crescent are adopting a Purchase of Development Rights (PDR) program. A Purchase of Development Rights is a voluntary program in which a landowner agrees to sell his or her development rights to a government (local, state, or federal) in return for a cash payment. A reasonable, though aggressive, goal according to the consultants would be to preserve 8,000 acres through a PDR program. This level of preservation would maintain the largely rural character of the agricultural parts of the Rural Crescent. The consultants recommend that the County appropriate $5 million to begin funding the program using local and non-local revenue sources that are further outlined in the report (see section 4). Five million dollars could preserve at least 1,000 acres using a cap of $5,000 per acre and with additional acreage possible through leveraging state and federal matching funds and partnering with preservation-oriented organizations. There are several existing programs for matching.

The consultants also recommend that the County explore the creation of a Transfer of Development Rights (TDR) program. A transfer of development rights (TDR) program creates a market in development credits through the county government. The County would give development credits to landowners in a designated preservation area. A system of TDRs allows ownership of the development rights on a privately owned parcel of land to be separated from ownership of the parcel itself. These rights can then be transferred from that property to another property in a different location that has been designated as a receiving area and that the county will allow higher density development if TDRs are purchased. Having transferred the development rights, the original landowner and all future owners of that property are restricted from developing the land by a conservation easement or deed restriction. The buyer of the development rights uses them to develop another piece of property with more density than allowed by its comprehensive plan zoning.

Protected areas, the sending areas, should be the highest value agricultural, scenic, and culturally significant parts of the Rural Area. Receiving areas would be: appropriate locations in the Comprehensive Plan’s Development Area; what the consultants calls Nokesville Village, Sector Plan Core Area; and areas within the Transitional Ribbon (see diagram below) where higher density development would be more protective of environmental resources and rural character than development of the sending areas.
the proposed Rural Character Areas

Thursday, May 1, 2014

Supreme Court Revives EPA Rule Targeting Coal Power Plants

EPA's breakdown of power plant pollution
On Tuesday the U.S. Supreme Court ruled (6-2) that the U.S. Environmental Protection Agency (EPA) can reinstate the  Cross State Air Pollution Rule, CSAPR, which allows EPA’s "cost-effective allocation of emissionsreductions among upwind states”  by requiring some state to clean up more than their fair share of pollution. CSAPR dictates each State’s emissions reduction goals and the Federal Implementation Plans to obtain those goals at the State level. However, the EPA had used computer modeling to generate emissions “budgets” for each upwind State without regard for the amount of pollution each state was contributing to a downwind problem, but based instead on the cost of remediation. Now the Supreme Court has confirmed requiring the level of cleanup to be based on cost and requiring more work to be done where the cost of capturing a ton of sulfur-dioxide and nitrogen-oxide was the lowest creating a pollution trading system.

Back in  August 2012 the U.S. Court of Appeals for the District of Columbia ruled (2-1) that the Cross State Air Pollution Rule, CSAPR, exceeded the U.S. Environmental Protection Agency’s authority by requiring some state to clean up more than their fair share of pollution. The Supreme Court has overruled that decision. CASPR was intended to prevent pollution from one state from moving into other states and preventing them from meeting their air quality goals. CSAPR, when implemented will reduce SO2 emissions by 73% from 2005 levels and NOx emissions by 54% at the approximately 1,000 coal fired electrical generation plants in the eastern half of the country. The industry has indicated that many of these plants may be forced to close. This rule is intended to help downwind states unfairly impacted by upwind states attain their 24-Hour and/or Annual particulate pollution of 2.5 micrometers or less called PM2.5 National Ambient Air Quality Standards (NAAQS) and the 1997 8-Hour Ozone NAAQS. CSAPR will replace EPA's 2005 Clean Air Interstate Rule (CAIR). 

The earth’s atmosphere is interconnected. That is accepted when it comes to carbon dioxide, but it also applies to industrial pollutants and soot. The EPA has estimated that just one-quarter of U.S. measured pollution emissions from coal-burning power plants are deposited within the contiguous U.S. The remainder enters the global cycle. Conversely, current estimates are that less than half of all measured coal pollution emissions deposited within the United States comes from American sources. According to the Mount Bachelor Observatory, Chinese exports include acid rain that falls in China, Korea, and Japan, and pollutants that enter the air stream including sulfates, NOx, black carbon, soot produced by cars, stoves, factories, and crop burning. EPA can now address these pollutants based on the cost of remediation instead of based on contribution by a state.

However, as a president, CSAPR may do much more. In the next two months the EPA is expected to propose a new sweeping set of Clean Air Act regulations to cut emission of carbon dioxide to fight global warming. According to the EPA the largest source of carbon dioxide is coal fired power plants, this decision will mark the end of the era of using coal to generate electricity in power plants. This era began with the oil crisis in 1972 and will end with CSAPR. However, using this decision EPA can allocate carbon dioxide “budgets” based on costs to meet the budget and potentially creates a national carbon trading market for carbon dioxide. In addition, it could create interstate trade and tariff  issues when allocating carbon dioxide and methane “budgets” in a world of greenhouse gas caps and trade markets.
from EIA