Thursday, July 28, 2011

The Dead Zone






For the past few decades dead zones have become a yearly occurrence. Dead zones form in summers when higher temperatures reduce the oxygen holding capacity of the water, the air is still and especially in years of heavy rains that carry excess nutrient pollution from cities and farms. The excess nutrient pollution combined with mild weather encourages the explosive growth of phytoplankton, which is a single-celled algae. While the phytoplankton produces oxygen during photosynthesis, when there is excessive growth of algae the light is chocked out and the algae die and fall below the interface between the warmer fresh water and fall into the colder sea water. The phytoplankton is decomposed by bacteria, which consumes the already depleted oxygen in the lower salt level, leaving dead oysters, clams, fish and crabs in their wake.


In a wedge estuary such as Chesapeake Bay where the layers of fresh and salt water are not well mixed, there are several sources of dissolved oxygen. The most important is the atmosphere. At sea level, air contains about 21% oxygen, while the Bay’s waters contain only a small fraction of a percent. This large difference between the amount of oxygen results in oxygen naturally dissolving into the water. This process is further enhanced by the wind, which mixes the surface of the water. Scientists are just beginning to study the impact of the winds in delivering oxygen to various water layers. The other important sources of oxygen in the water are phytoplankton and aquatic grasses which produce oxygen during photosynthesis, but when they die consume oxygen during decomposition by bacteria. Finally, dissolved oxygen flows into the Bay with the water coming from streams, rivers, and the Atlantic Ocean. http://www.dailypress.com/news/science/dead-rise-blog/dp-scientists-say-wind-reduces-chesapeake-bay-dead-zones-20110725,0,7046457.story?track=rss

Water temperature and total river flow are linked to the size of the summer dead zone. The peak of oxygen depletion typically occurs in July or August. Water temperatures are highest during these months and the days are longest accelerating the growth of phytoplankton that ultimately consumes all the dissolved oxygen. The dead zone is typically gone by November. Cooler air temperatures at this time of year chill the surface waters, while the deeper water remains warm and allows more mixing of the layers during storms. Cooler water also will hold more oxygen. The size and shape of the dead zone is variable from month to month during the summer. Typically, the largest dead zones occur in years with the highest spring snow melts and rains. Though this year may surpass it, 1993 had the largest cumulative spring river flows of the past 22 years and the largest average summer dead zone with an average of 5.2% of the channel.

River flow volume is linked to increased size of the dead zone because the heavy rains and snow melt that create the river flow carry excess nutrients of nitrogen and phosphorus from agriculture, septic systems, overflows from sewage treatment plants and runoff from lawns, gardens and paved surfaces. These nutrients fuel the out of control grow of the phytoplankton that overwhelms the natural system. The decomposing phytoplankton, combined with higher water temperatures, can cause large areas of the deepest parts of the Chesapeake Bay's deep channel which is the ancient Susquehanna riverbed to have little or no oxygen to support marine life.

These excess nutrients are washed from agricultural fields and animal / feed lots as well as from suburban yards. The Chesapeake Bay Foundation has emphasized the importance of agricultural nutrient management plans and the Commonwealth is phasing out the use of phosphorus in ornamental lawns. However, an additional significant contribution to the excess nutrient contamination during storms is from waste water treatment plants and over taxed sewer systems. The sewer system in Baltimore (where the dead zone begins) still overflows with frightening regularity despite a consent order with the EPA signed in 2002. In a single storm in mid March of this year 4.7 million gallons of untreated but diluted sewer water overflowed from city sewer lines. That was just one of many spring storms. The Baltimore public works department is in the 8th year of a $1 billion rehabilitation of the city's aging, leaky sewer system, which won't be finished for several more years. In Washington DC one third of the sewer system is a combined system that is also subject to direct release of sewage during storms and snow melt. Combined sewer systems are sewers that are designed to collect rainwater runoff and domestic sewage, and industrial wastewater in the same pipe. http://cfpub.epa.gov/npdes/home.cfm?program_id=5
http://articles.baltimoresun.com/2011-03-14/features/bs-gr-sewage-overflows-20110314_1_overflows-sewer-lines-jones-falls

The combined efforts of state and local governments with conservation organizations have made much progress since 1978 in improving the health of the Bay, but are still short of the regional goal. According to the indices created by the Chesapeake Bay Foundation, The Chesapeake Bay Program and Chesapeake EcoCheck, there has been little if any progress in the past decade in the health of the estuary. The size of this summer’s dead zone puts a big exclamation point on the work that still needs to be done to restore the health of the Chesapeake Bay estuary. http://stateofthecoast.noaa.gov/hypoxia/dead_zone.html

The Chesapeake Bay is not the only estuary with a dead zone. Dead zones have become common summer events caused by man, human waste, and the waste and excess nutrients from agriculture necessary to feed us and ornamental gardens to please us. It has be predicted by Researchers from Texas A&M University that the Gulf of Mexico dead zone currently estimated at 3,300 square miles will exceed the typical summer average of 5,600 square miles. The scientists are predicting more than 9,400 square miles of dead zone in the coastal waters of the estuary due to the record flooding in the Mississippi valley that flooded fields and towns up and down the river during the spring carrying with the flood waters the excess nutrients from farms, yards, septic systems and sewage treatment plants in its wake. The Gulf of Mexico Dead Zone is not expected to peak until late August.

Monday, July 25, 2011

The Value of Solar Renewable Energy Certificates (SRECs)

Solar Renewable Energy Certificates, SRECs, are not real, they are environmental “commodities” created by regulation that was born in New Jersey in 2004-2005 as a way to encourage and support the growth of solar energy within the states that utilize them. SRECs are not physical entities, but merely a credit for having made power. Like most consumer solar arrays I use all the power produced by the panels in my own home, nonetheless, my system generates 10 SRECs a year. Because SRECs are not physical items their value depends entirely on regulation which can change over time and that is the inherent risk in making financial decisions based on regulations. There was always a risk that some (or all) SRECs could become worthless at any time if regulations change. Some SRECs were actually designed in a way that would decrease in value over time and state legislatures have stepped in to prevent that.

SRECs are created by state regulations. In order for SRECs to have any value, the states must have a mandated Renewable Portfolio Standard, RPS, the SRECs must be tradable and there must be a punitive financial penalty for not meeting a solar carve out portion of the RPS. A renewable portfolio standard (RPS) is a state legislative requirement for utilities to generate or sell a certain percentage of their electricity from renewable energy sources. The percentage requirements under RPS programs vary widely from state to state, but for SRECs to have any real value there must be a solar carve out and be tradable. http://www.epa.gov/chp/state-policy/renewable_fs.html

In some states with solar grant or rebate programs the utility company owns the SRECs so that the homeowner can not sell them. This has worked in states like California where electricity rates are high and tiered and the solar installation market has become is more competitive and utility payments effectively fund solar rebates. As of September 20, 2010, 36 states plus the District of Columbia and Puerto Rico have enacted an RPS or a renewable portfolio goal (RPG). Of these states, only New Jersey, Maryland, Washington DC, Delaware, Ohio, Pennsylvania, and Massachusetts have assigned a multiplier to Solar RECs and created a separate SREC market where the homeowner or facility owner maintains ownership of the SRECs.

The legislation creating SRECs and RPS in various markets is always in flux. In the District of Columbia, the RPS market has requirements of about 7.6 megawatts of installations for next year, but there are over 45.7 megawatts of solar photovoltaic systems currently registered and certified in DC that are eligible for the DC SREC market. Only 1.2 MW of the 45.7 megawatts are actually located within the District. In Pennsylvania the RPS requirement for next year is 44 megawatts and there are 104.8 megawatts of solar photovoltaic systems currently registered and certified in that state with only 36.3 are actually located in Pennsylvania.

Even in a market created by regulation, the relationship between supply and demand creates the price. A market that cannot attract the supply to meet the mandated demand will have above market SREC prices until the supply increases this is effectively what happened in New Jersey’s closed market with aggressive RPS requirements. An open market that attracts too much supply too quickly would face a collapse in SREC pricing. Virtually all states have more SRECs available for sale than mandated RPS at this time. Price collapse has occurred in the states with open markets and small RPS requirements. This situation creates the dynamics for legislatures to limit access to these open markets in the future to protect in-state generators or conversely to slow the development of solar projects in the eligible adjacent states. That is the problem in markets dependent on regulation for their existence a state legislature will determine the ultimate return I get on my investment in solar photovoltaic panels.

New Jersey, Maryland, Delaware and Massachusetts have SREC markets closed to out of state facilities. Ohio, Pennsylvania and Washington DC allow sale of SRECs of facilities in adjacent states. New Jersey and Massachusetts have additional mechanisms to protect the market SREC value and the instate market from significant oversupplies like those seen in Pennsylvania and DC. New Jersey pioneered the SREC program in their 2004 and launched in 2005. In the early years, in addition to closing its borders to out-of-state facilities, New Jersey placed a cap on the size of project eligible for the SREC market to protect the small generator. There is also a protection to the SREC value in the Solar Alternative Compliance Payment that is the punitive fee for failing to meet the solar carve out. Massachusetts has made a 10 year commitment to their program setting a floor price of $300.

Virginia where my solar panels are located does not have a mandated RPS, it is voluntary. In addition, Virginia does not have a solar carve out in their voluntary standard. All REC are priced the same in Virginia at about $15 a megawatt as I would be competing against the landfill gas generators such as the Prince William County landfill. In addition, my electric cooperative sells power at a very low cost (about 11.5 cents per kilowatt over 300). I am eligible to sell my SRECs in Pennsylvania and Washington DC. Currently both of these markets have and oversupply of SRECs and the price has collapsed. Two factors have created this dynamic; there is no cap on the size of eligible projects and the recent SREC prices, state rebates in several states and federal tax credits that had effectively reduced the cost of solar installations increasing both the return on investment and thus the supply of solar installations and SRECs. Large projects and small consumer projects responded to these incentives and anticipated SREC payments to overbuild solar installations. The time lag inherent in SREC generation feeds the market inefficiency.

This delay has created the price collapse in the market. Too much supply of SRECs entered the market over the past 18 months before SREC prices were able to indicate to the market that it needs to slow growth. At this point, one of two things is likely to happen, either growth of solar projects will slow in the markets where the SREC price has collapsed (Washington DC and Pennsylvania) or the states will incorporate a price support feature into their market. That price support could either come in the form of a floor price akin to that seen in the Massachusetts market, or a mechanism that triggers a requirement increase in the event of a price collapse. Often these price supports are accompanied by closing the market to avoid paying out of state generators with local rate payer money. On the other hand if more states create open SREC markets, the price support could come in the form of shifting supply from one state market to the next. If each facility is eligible in several states, the market becomes more diverse and subsequently more secure. However, regulators tend to choose to protect their own and their faith in open markets is not something I would bet on. At this point it appears that my investment in solar panels will return will be less than I hoped.

The total installation cost was $58,540. I obtained the Virginia Renewable Energy Rebate of $12,000 and the 30% tax credit of $13,962 and my total out of pocket cost for my solar system after the first year is $32,578. A rough estimate using the DOE model of my savings on electricity is $1,400 per year. This past year I earned $1,045.94 in SREC income for the partial year that my panels were installed. That is slightly over a 7.5% return on my investment last year. Now my future returns do not look as bright. My husband, an experienced investor, has reacted well to this lowering of anticipated return on investment reminding me that our own power generation savings is worth more than 4% each year at the current cost of electricity.

Thursday, July 21, 2011

Tree Deaths from Herbicide Use




This spring as usual I prepared my garden for summer, deadheaded some of perennials (which I promise to do more aggressively this year in early winter), cleanup the dead leaves and remove any dead plants. The incredibly harsh winter of 2009-2010 followed by the heat wave last summer killed off four shrubs and 6 evergreens. It was a sad and expensive loss. In preparation for planting the six replacements and one additional tree I purchased seven Treegator Pro Jr. watering bags to ensure that my hollies and Crytomeria would be watered for their first season. For extra insurance I planted them with seaweed and fish heads. Even after the 100 degree days in May and June and the return of heat in July my new trees are looking good.

However, I can not say that about my Japanese dogwood. It is withering. After four years of surviving the hot summers of Virginia it is withering and so I began my investigation when I noticed one more odd thing in my garden. In the stone garden around my septic controls the weeds had withered. In no other place in my garden had the weeds withered. I do not use herbicides or pesticides in my garden. The beds are weeded by hand. Weeding is the work of gardeners. So what had caused the weeds to die off in this little spot and was that related to my Dogwood? Despite my asking my septic service company and the company that cuts my lawn there seems to be no source of herbicides on my garden. However, while I was investigating my problem I came across the suspected Imprelis caused tree deaths.

University Extension websites from Kansas to Pennsylvania have reported injury to evergreens on lawns and golf courses treated with Imprelis. Homeowners, lawn service operators and others have observed browning of shoots and needles and twisting and stunting of shoots, especially near tops of trees. Symptoms are usually most severe on current year growth on tree tops and outer branches. Unlike insect and disease problems, Imprelis damage occurs quickly, within two to three weeks of application. The most commonly affected trees are Norway spruce, Colorado blue spruce and eastern white pine. Firs and yews may also be affected. My dogwood is a Cornus species and not reported to be impacted.
http://news.msue.msu.edu/uploads/files/122/Imprelis%20homeowner%20factsheet_Bert%20Cregg.pdf

Imprelis is a new herbicide from DuPont, approved for use in 48 states last fall. The U.S. Environmental Protection Agency approved Imprelis (aminocyclopyrochlor) last year for commercial use in controlling dandelions, ground ivy, violets, clover and other weeds in lawns. It’s not available for use by homeowners, so it is unlikely that my neighbors used it. In addition, the damage from Imprelis appears unlikely to be from pesticide drift. Imprelis was developed and marketed to control weeds in lawns and works by both direct uptake through the leaves as well as root uptake by interfering with a plant’s normal hormonal balance. It was designed to be long lasting and does not break down easily. Imprelis is not approved for use in New York and California because both states have separate review procedures for new herbicides. New York State officials identified a problem: the herbicide does not bind with soil, and may leach into groundwater. California has not completed its review.
http://www.nytimes.com/2011/07/15/science/earth/15herbicide.html?pagewanted=all

Reportedly, Imprelis went through about 400 trials, including tests on conifers, and reportedly performed without problems. The U.S. Environmental Protection Agency reviewed the herbicide for 23 months before granting its conditional approval, though all of the safety data was not yet in, the agency believed Imprelis to be a good product. Now, however, The EPA will begin an "expedited review" by the end of July into whether the weed-killer Imprelis is harming or killing some species of evergreens. Most Imprelis applications have not reported damage to spruce or pine, but cases of damage cause alarm when dealing with a newly released herbicide.

The reported cases from Indiana indicate that this may not be a simple herbicide drift issue, but rather from root uptake. Clippings from lawns treated with Imprelis should not be composted because the chemical survives the process and can kill flowers and vegetables that are treated with the compost. That warning is included on the Imprelis product label. The types of trees that are reported to be most commonly affected typically grow vigorously and are therefore good candidates for recovery from minor injury. Reduce drought stress by watering during dry periods. Avoid over-watering that causes water-logging. This is the same advice that the forest service and nursery gave me to try and save my dogwood.
http://news.msue.msu.edu/news/article/what_to_do_with_imprelis_affected_trees

I am reminded of my neighbor’s comment about how bad the dandelions were this spring. My own reaction was to embrace dandelions as pretty and anything green growing in what passes for a lawn around here is considered good- crab grass, clover and other weeds. We need to rethink the use of herbicides in ornamental gardens. Unintended consequences.

Monday, July 18, 2011

Recycling and Trash




If we are to live sustainably on this earth we need to think beyond our carbon footprint and try to reduce our wasting of the Earth’s natural resources and our own resources. In 2009, Americans generated about 243 million tons of trash and recycled and composted 33.8% of this trash (or 82 million tons) mostly through curb side recycling services. On average, Americans recycled and composted 1.46 pounds of our individual waste generation of 4.34 pounds per person per day. According to Scott MacDonald, Recycling Program Manager of the Prince William County Landfill, we in Prince William County Virginia generate 5.65 pounds of trash per person per day and only recycle about 32%. Much of this trash could have been reused or recycled or in many instances not purchased in the first place.

We need to reduce our waste. Our trash, or municipal solid waste as it is more properly called, is made up the things we buy and then throw away. Our household and commercial waste includes paper (magazines, newspapers, advertising, computer print outs) packaging, food scraps, grass clippings, sofas, computers, old tires, broken electronics and appliances, old clothes, broken dishes, and old appliances. Municipal solid waste does not include industrial, hazardous, or construction waste (except small builder or homeowner construction waste). As the population grows we have been generating more and more waste, but we have also increased the waste generated per person from an average of 2.68 pounds per person in 1960 to the current level of 4.34 pounds per person, a 61% increase. The peak average per person trash generation was in 2000 when the United States generated on average 4.72 pounds of trash per person. It is to be noted that the recycling rate went from 0% in 1960 to almost 34% in 2009. The EPA and lots of other groups has a list of suggestions to reduce the amount of trash that we produce, read it, some of the suggestions are simple painless steps, others will save you money. See what changes you can make.

The EPA estimates that residential waste (including waste from apartment houses) to be 55% to 65% of total trash generation. Waste from commercial and institutional locations, such as schools, hospitals, and businesses, accounted for 35% to 45% of total waste. Mr. MacDonald could only speculate why the trash generation per person in Prince William County exceeded the national averages. He thought it might be because we are an affluent community, but there could be demographic or cultural causes that produces the higher generation rate here. Whatever the reason, we need to improve both in total trash generation and the percentage of trash recycled. We need to move away from the disposable, single serving container behaviors and reduce, reuse and recycle. Really.

More than 77% of the typical waste can be recycled. According to the EPA the municipal solid waste typically consists of 28% Paper and paperboard, 28% is yard trimmings and food scraps (which can all be composed and really should not be buried in the landfill), 12% Plastics, 9% Metals; 8% rubber, leather, and textiles, 7% Wood, 5% glass and 4% Other miscellaneous wastes. Mr. MacDonald believes that the make up of the Prince William municipal solid waste is probably very similar to the national averages, but no analysis has ever been done.

The Prince William Landfill on Dumfries Road provides areas for depositing reusable items like clothing, furniture and functioning (and non functioning) appliances. In the front area of the landfill are Tire Recycling containers for disposing of used tires. These tires are ground up and used as cover for the land filling operation. There are also Scrap Metal Recycling containers for recycling metal items such as appliances, auto parts, bicycles, swing sets, mowers (with all the fluids removed), metal pipe, metal fixtures, metal siding, chain, microwave ovens, sheet metal, tire rims, chain link fencing, cable, and other similar metal items. Recovered metal is often sent overseas where the manufacturing of such items actually takes place. Refrigerators, freezers, air conditioners and other Freon containing appliances must be placed in a special designated area so that the Freon can be removed and properly disposed of or recycled depending on the age and type of the coolant fluid. There is an area for bottles and cans, mixed paper, newspapers, magazines, corrugated cardboard, and Special Waste Recycling for hazardous household waste requiring special handling (motor oil, oil filters, anti-freeze, car batteries, florescent light bulbs and household batteries). There is an area for Yard Waste/Brush containers for grass and leaves and brush recycling these materials will be turned into mulch or compost. Finally, there is a great place to leave items that still have usable life like used furniture, the Too Good to Waste Place. This is a great way to give away household items. Of course there is a regular Trash Disposal area with large containers for disposing of non-recyclable waste.

Many residents have trash pick up service with curb side recycling. The curb side recycling is also call single stream recycling because all recyclable waste is mixed together in one collection container at the curb. In some places the newspapers are separately recycled (and my husband still likes to separate the newspapers). The commingled recycling is then hauled away to a recycling center (not the landfill) that is equipped to process and separate recycling that is single streamed. The materials are then sorted by the type of recyclables. In Prince William, Fairfax, and Loudoun counties the recyclables are hauled from our curbs to a Waste Management single stream recycling facility in the region where the recyclables are separated and processed. As Waste Management has expanded its capabilities more and more types of materials are now acceptable. Waste Management has expanded it capabilities and shortly your trash collector will be able to collect newspapers, magazines and catalogs as well as other types of paper, paperboard packaging, cardboard, plastic containers #1 through #7 narrow neck and wide mouth containers and tubs, metal food and beverage cans, spray cans (no hazardous substances), aluminum foil wrap and pie pans with food residue removed and balled up. Milk, juice and soup cartons (without the plastic caps and straws) and glass bottles and jars. The expansion in items acceptable for recycling should be in place shortly and we can all expand our recycling.

Thursday, July 14, 2011

Landfills a History

Historically trash had just been “tossed” out of our living areas. In cities trash and human waste was simply thrown into the streets or outside the gates. As cities became more populated and disease spread mankind came to the realization that throwing waste into the streets was contributing to the spread of devastating disease outbreaks and making cities centers of filth and disease. Bubonic Plague, Cholera, and Typhoid fever were just a few of the diseases spread by filth that harbored rats, and contaminated water supplies. It was not uncommon for European city dwellers to throw their trash and human wastes out of the window to decompose in the street. During the 1800’s the connection between disease, sewage, trash and filth was discovered. Though there was tremendous resistance most famously in France, by the late 1800’s cities created garbage collection and disposal systems using horse-drawn carts to collect garbage and dispose of it in open dumps, incinerators, or at sea. In New York City in 1916 the garbage collection took in 4.6 pounds of garbage per person per day.

During the first half of the 20th century when garbage was routinely collected incineration was a common method of disposal. Many apartment buildings were constructed with garbage incinerators in the basements and trash shoot systems. In the 1920’s it was common for garbage, incinerator ash, and dirt to be used to fill in swamps near cities which allowed the contamination of groundwater. The precursor to the modern landfill was first tried in California in 1935. Trash was thrown into a hole in the ground that was periodically covered with dirt. In 1959 the American Society of Civil Engineers first published guidelines for a “sanitary landfill” that suggested compacting waste and covering it with a layer of soil each day to reduce odors and control rodents. Even at this point landfills were designed by excavating a hole or trench, filling the excavation with trash, and covering the trash with soil. In most instances, the waste was placed directly on the underlying soils without a barrier or containment layer (liner) that prevented water percolating through the waste and picking up contaminants know as leachate from moving out of the landfill and contaminating groundwater.

The first federal legislation addressing trash or more properly solid waste management was the Solid Waste Disposal Act of 1965 (SWDA) that created a national office of solid waste. In 1976, the Resource Conservation and Recovery Act (RCRA) expanded the federal government’s role in managing waste disposal. RCRA divided wastes into hazardous and solid waste categories, and began the process of developing standards for sanitary landfills and closing or upgrading existing dumps to meet the sanitary landfill standards. (The Office of Solid Waste was transferred to the US EPA in 1974. I met my husband when the Office of Hazardous Waste was combined with the Office of Solid Waste where I worked in shortly thereafter.)

In 1979, EPA developed the first set of criteria for sanitary landfills that included standards for locating new landfills and operational standards for existing landfills to reduce disease vectors and increase protection of surface and groundwater. RCRA was amended in 1984 to require EPA to assess and revise the sanitary landfill requirements. Finally, in 1991, EPA established new federal standards for municipal solid waste (MSW) landfills that updated location and operation standards and added design standards, groundwater monitoring requirements, corrective action requirements for known environmental releases, closure and post-closure care requirements, and financial assurance requirements to ensure that there would always be adequate funding to maintain closed landfills. During my environmental career, landfills changed from little more than holes in the ground to highly engineered, state-of the-art containment systems requiring large capital expenditures. http://www.epa.gov/osw/nonhaz/municipal/landfill.htm

Modern landfills are specifically designed to protect human health and the environment by controlling water and air emissions. Modern landfills are built as a series of cells. The cells include liners of plastic membranes and watertight clay on the bottom and the leachate collection systems to prevent groundwater contamination. Liners prevent leachate and methane and CO2 gas migration out of the landfill while directing liquids to the leachate collection system. Liner systems are typically constructed with layers of low permeability, natural materials (compacted clay) and/or synthetic materials (high-density polyethylene). The leachate collection system removes the liquid contained in the liner. A typical leachate collection system may consist of (from bottom to top) a perforated leachate collection pipe placed in a drainage layer (gravel). The leachate is collected, filtered, typically tested and sent on to waste water treatment either on or off site. At the end of each day, the waste is covered with six inches of soil or an alternative daily cover (foam, tarps, ground tires, incinerator ash, compost) to control the spread of disease through birds and rodents, odors, fires, and blowing litter.

Virginia has roughly 60 solid waste landfills still in operation there are closed landfills required to be monitored and maintained according to regulation. There are 134 counties and cities in Virginia, so solid waste management has become a regional operation. In 1993, the General Assembly mandated in a law known as "HB 1205" that existing landfills that did not meet the new regulations must be closed and could not maintain their grandfathered status. Old landfills would be permitted to continue accepting waste until their existing facilities were filled, but no horizontal expansion of old landfills would be permitted and the older landfills must then be caped and monitored. All new cells, at old or new landfills, would have to meet stricter requirements for liners, clay caps, leachate collection systems, gas release/collection systems, and monitoring. Older landfills would have to be stabilized to prevent contamination of groundwater.

Monday, July 11, 2011

Prince William County Landfill and Renewable Energy



On Friday, July 8th at the Potomac Watershed Roundtable meeting Thomas Smith, Solid Waste Division Chief of the Prince William County Public Works Department gave a presentation on Utilizing the Landfill Gas for Renewable Energy Production followed by a tour of the Prince William Landfill.

Prince William County residents pay a flat fee ($70) every year on their property taxes so there is no tippage fee at the landfill. This fixed fee that grows with population allows the landfill to have a steady cash flow to maintain their monitoring and remediation programs and plan smooth expansion and improvement programs. Trash generation in general grows with population, but it is surprisingly subject to the economy. The population of Prince William County was 281,287 in 2000 and grew more than 43% to 402,002 in 2010. In 2000 238 thousand tons of trash was disposed at the PW Landfill. The peak tons of trash disposed the PW Landfill was 367 thousand tons in 2007 in 2010 285 thousand tons of trash were disposed at the landfill. To put that in perspective, in 2007 it was estimated that Prince William Residents generated about 6 lbs of trash per day per person; today that number is less than 4 lbs of trash per day per person. Approximately, 32% of the trash is recycled, 10% is recovered as energy, and 58% is buried in the landfill. According to Mr. Smith much of the trash going to the landfill could have been recycled, but recycling and the recycling center at the landfill is a topic for another day.

Prince William Landfill is right off of Dumfries Road in Manassas, VA and has operated at this location since 1972. The oldest section of the landfill contained 57 acres that were closed in 1991 when the state law known as HB 1205 went into effect. That area is currently used for little league fields and have been undergoing retrofit with liners and leachate and landfill gas collection systems to protect the environment. Today Prince William County Landfill is engineered and built as a series of cells. The cells include liners of plastic membranes and watertight geosynthetic clay liner fabric on the bottom along with a leachate collection system. At the end of each day, earth covers the trash deposited in the cell, to keep animals away and improve aesthetics. When a cell if full it is capped to prevent (or at least limit) the rain that percolates through the landfill and covered in soil. Currently, the landfill is capping the Phase I section and opening up a newly lined cell in the Phase II area.

The PW Landfill has 48 groundwater monitoring wells that are observed and/or sampled quarterly to ensure that groundwater is not impacted or any impact is contained and 78 landfill gas extraction wells. Landfill gas is generated during the natural process of bacterial decomposition of organic material contained in the trash buried in the landfill. Landfill gas is approximately forty to sixty percent methane, with the remainder being mostly carbon dioxide. Landfill gas also contains varying amounts of nitrogen, oxygen, water vapor, sulfur, and other contaminants. The gases produced within the landfill are either collected and flared off or used to produce heat and electricity. The landfill gas cannot be allowed to build up in the landfill because of the explosive potential. PW Landfill has operated for almost 40 years and has more than 7 million tons of trash buried at the landfill. That trash currently generates 2,700 standard cubic feet per minute of landfill gas up from 1,600 scf/m in 1999.

Landfill gas can be used as a source of energy to create electricity or heat. It is classified as a medium-Btu gas with a heating value of 350 to 600 Btu per cubic foot, approximately half that of natural gas, and can be used in place of propane and natural gas in some application. It is a reliable source of energy because it is generated 24 hours a day, 7 days a week. Landfill gas is a renewable energy source. Landfill gas that is used to produce energy does not have to be flared and wasted to prevent explosive gas build up. Flaring of landfill gas at PW landfill is done in a candle flare an open air flame that you have probably seen at night. In 1998 the County formed a partnership with NEO Prince William to install a landfill gas collection system and a 1.9 MW energy recover facility which is a two engine turbine that burns the gas to make electricity that is sold to NOVEC, the local electric cooperative. The 1.9 MW energy recovery system was utilizing less than 25% of the currently available landfill gas for energy recovery.

NEO was acquired by Fortistar Methane Group. Fortistar has since obtained the VDEQ permits for four additional engine turbines. Negotiations with NOVEC were more difficult because Virginia has no renewable energy requirements, but 3 MW of additional engines will go on line this year for a total constant energy production of 5 MW. This will produce $40,000 annual revenue to the Solid Waste Fund and $20,000 in personal property tax revenue in the first year. Even after the new engines go online this year there will still be 200 scf/m excess landfill gas available. A new gas pipeline has been installed to provide landfill gas to heat the landfill’s Fleet Maintenance Building and extended to provide fuel to the County animal shelter cremation incinerator to replace propane. The payback for the pipeline installation is estimated to be 8-10 years. Propane use will be reduced 56% and the savings to the general fund will be $25,000-$35,000 annually.

As the landfill continues to operate, adding closed cells and opening new cells, more landfill gas will be produced for generations. Prince William County views the landfill as an under utilized resource and is studying options for creating a Prince William Renewable Energy Park. The PW Landfill has applied to EPA for technical assistance in performing feasibility studies for the potential options.

Thursday, July 7, 2011

Global Warming, Fuel Economy, and Uncertainty




According to the data in Steven F. Hayward’s 2011 Almanac of Environmental Trends which is the latest adaption of the former Index of Leading Environmental Indicators, global temperatures were flat or slightly declining between 2002-2008 before ticking up slightly in 2009. When data from 2010, an El Nino year, becomes available it is expected to challenge 1998 (also an El Nino year) for the warmest year on record. Without the El Nino years in the data; the long term upward trend of temperatures is more visible in the data, but more than two decades of data is necessary to see, let along understand global trends.

Global CO2 concentrations in the atmosphere as measured from the Mauna Loa Observatory in Hawaii where the level of ambient greenhouse gases are measured show an increase of 1.78 parts per million in 2009. The United States CO2 emission growth has been flattening out after the steep growth in the 1990’s and fell slightly during the recession. The CO2 emissions intensity in the United States has declined 28.8% since 1991. Emissions intensity is the measure of the amount of CO2 emitted per dollar of economic output. The key factors in CO2 intensity is the method and efficiency of electricity generation and automobile and truck mileage and emissions.

The climate of the earth is constantly changing on a geological time scale, but the geological record hints that sudden shifts can happen. The controversy over both the science and policy relating to climate change is far from over. Policy mandates to have the United States adopt constraints on fossil fuel energy consumption have changed forms. We now speak of energy independence and fuel efficiency to achieve these goals. According to the US EPA, transportation represents 27% of greenhouse gas emissions. Passenger cars, light trucks and motorcycles represent 62% of the transportation greenhouse gas emissions.

The U.S. Environmental Protection Agency (EPA) and the Department of Transportation’s National Highway Traffic Safety Administration (NHTSA) are currently finalizing the new millage and emission standards for automobiles and light trucks for model year 2012 through 2016. The EPA GHG standards require these vehicles to meet an estimated combined average emissions level of 250 grams of carbon dioxide (CO2) per mile in model year 2016, equivalent to 35.5 miles per gallon (mpg) if the automotive industry were to meet this CO2 level all through fuel economy improvements. http://www.epa.gov/oms/climate/regulations/420f10014.htm
However, the potential need to utilize coal fired electric plants to meet this requirement may negate the GHG benefits.


Now the administration is looking to continue this trend until 2025 requiring continued improvement of about a 5% per year in average fuel economy from 2016 when they are required to have at least a 35.5 mpg fleet average for vehicles sold in the U.S. Under the new proposals automakers that sell vehicles in the U.S. will have to boost car and light truck fuel economy to an average 56.2 miles per gallon by 2025 using regulation rather than a direct tax on gasoline to reduce the use of fuel.
http://www.cbo.gov/ftpdocs/49xx/doc4917/12-24-03_CAFE.pdf


Increasing fuel economy by the amount proposed could cost at least $2,100 per vehicle, according to a document prepared last year by the EPA and National Highway Traffic Safety Administration. Representatives of the auto industry claim that the additional costs will be closer to $6,000 per car. The differences are how that cost is estimated and the assumptions made and whether additional safety technology are included in the costs. It is assumed by all sides that this goal can be achieved which is quite frankly amazing. The questions is how much of the automobile fleet will depend on plug-in electric vehicles, the cost of charging equipment, how long we will own our cars in the future, what cost of gasoline will be in the future, how much will the average American drive, and what is the appropriate discount rate. All these factors are incorporated into the projections of the costs to achieve this millage goal. For a good discussion of the calculation see the Consumer Federation of America discussion. http://www.consumerfed.org/pdfs/CFA-56MPG-by-2025-June-28-2011.pdf

I’m impressed that neither side thinks the task is impossible. That is fairly impressive, the question is how much will it cost and what impact will that cost have on our economy. There seems to be no appreciation by either the EPA or other regulators of the law of dimishing returns and the tendency of ever smaller improvements in gas mileage to cost more and more. Many of the materials needed for fleets of ultra-high mileage vehicles are not produced in enough volume. I think it is fair to say that cars will cost more and we will be poorer, but our gasoline used per mile will decrease and maybe our total gasoline use will decrease while our CO2 intensity is also reduced.

Monday, July 4, 2011

Data and the Environment

















I have just finished reading Steven F. Hayward’s 2011 Almanac of Environmental Trends which is the latest adaption of the former Index of Leading Environmental Indicators. The book is a quick read because Dr. Hayward loves charts and data in this particular effort so that there are a limited number of words. This annual publication can be relied upon to reframe several environmental issues by simply looking at the data differently. Also, Dr. Hayward in examining the trends over the past several decades seems to mirror some of my own optimism when it comes to environment. I was working in the environmental field in the 1970’s so I always see the vast improvement in the environment everywhere I look despite the huge increase in population since that time.

The water quality section has been vastly expanded to examine the data relating to the adequacy of water supplies and the health of several estuaries including the Chesapeake Bay estuary. The good news about water is that “on average” the United States uses less than 8% of the water that falls as precipitation within our borders annually. The happy perspective of Dr. Hayward is that water like solar energy is a renewable resource and that is mostly true. Unfortunately, precipitation varies from the average significantly on a regional basis and thus, allocations and supply on a regional basis will remain a problem especially in locations where irrigations is the major water use (mostly the western states). In addition, it is unknown in most locations if we are using groundwater in a sustainable way. Comprehensive data on groundwater use for the nation is not available. There is no monitoring of groundwater basins.

For example, in California a significant portion of the water supply comes from groundwater. Typically, groundwater supplies about 30% of California’s urban and agricultural uses. In dry years, groundwater use increases to about 40% statewide and 60% or more in some agricultural regions. This rate of groundwater use is unsustainable; California is mining its groundwater, using it at a rate higher than can be recharged. When you withdraw the groundwater from fine-grained compressible confining beds of sediments and do not replace it, the land subsides. The incredibly fertile Central Valley has been identified as the location of maximum subsidence in the United States. Once the land subsides, it looses its water holding capacity and will never recover as an aquifer. The groundwater in California may be a relic of the last ice age and is not being replaced or likely to be replaced under the current climate conditions.

The three estuaries covered in this year’s edition of the Almanac of Environmental Trends are the Gulf Delta, the Long Island Sound and the Chesapeake Bay. Unfortunately, the environmental report card for the estuaries is mixed. The bottom line with the Gulf of Mexico is that hypoxia, oxygen depletion; detrimental to aquatic life has been increasing. Dr. Hayward attributes this in part to incentives in the “well-meaning but ill-designed subsidy and conservation programs…especially subsidies for ethanol related corn production.”
The data after the Gulf oil spill is not included in the series so that the hypoxia can not be attributed to that.


Long Island Sound has shown a steady progress in habitat restoration, increased wetlands and an early achievement of the 2011 fish passageway restoration goals. The combined efforts of state and local governments with conservation organizations have made much progress but are still short of the regional goal. As for the Chesapeake Bay, according to the indices created by the Chesapeake Bay Foundation, The Chesapeake Bay Program and Chesapeake EcoCheck, there has been little if any progress in the past decade after making excellent progress during the previous 22 years. Dr. Hayward, always the optimist points out that while the population in the region exploded in the past decade, the health of the Bay got no worse, still, the Chesapeake Bay Foundation judges the Bay to be “dangerously out of balance.” Hopefully the various Watershed Implementation Plans from the six states and Washington DC will show great progress in the next decade. An interesting correlation in nitrogen and phosphorus contamination in the Bay is with rainfall as seen above. I had not appreciated how much nutrient contamination was correlated with runoff volume. Riparian buffer restoration and nutrient management improvements may be our most effective methods of meeting the Chesapeake Bay TMDLs.