Wednesday, June 12, 2024

EV's, Virginia and Me

My husband is taking the Acura in for service. It is displaying a service and maintenance code, so it needs attention. The Acura is 17 years old, though it only has only about 95,000 miles. Still, the time is coming to replace the vehicle. The question is with what.

Last week Governor Youngkin announced the end of the California electric vehicle mandate in Virginia, effective at the end of 2024when California’s current regulations expire. An official opinion from Attorney General Jason Miyares was that under the existing law Virginia is not required to comply with the new mandates called Advanced Clean Cars II adopted by the California Air Resources Board (CARB) set to take effect January 1, 2025.  

Under Advanced Clean Cars II, beginning in Model Year 2026, 35% of the new cars sold are required to be electric vehicles, moving up to 100% in 2035. If an auto manufacturer sells a gas powered automobile, they may be required to pay a fine upwards of $20,000 per vehicle sold. Given that EVs were only 9% of vehicles sold in Virginia in 2023 this could have resulted in hundreds of million of dollars in penalties- that would have served to increase the costs of cars for Virginians.

Nonetheless, the Federal Government has set a goal to make half of all new vehicles sold in the U.S. in 2030 zero-emissions vehicles. So, is it time for us to consider an EV? Today, transportation is the largest source of energy-related CO2 emissions in the U.S.  It could make a big difference in my personal carbon emissions, but EV adoption has the potential to drastically impact our local power grid. The proliferation of data centers in our region. Dominion Energy in Virginia predicts that by 2035 the data center industry in Virginia will require 11,000 megawatts from them, nearly quadruple what it needed in 2022, or enough to power 8.8 million homes. Northern Virginia Electric Cooperative recently told PJM that the more than 50 data centers it serves account for 59% percent of its energy demand. It expects to need to serve about 110 more data centers by July 2028.

In their most recent IRP Dominion Energy forecast that EV adoption will have its greatest impact on summer peak load because EV owners are expected to be charging their vehicles at the end of the day when summer peaks occur. Dominion forecast that in 2037, the estimated contribution to summer peak from EV charging will be approximately 358 MW or 6.4% of peak summer demand. While the Virginia power mix has been migrating away from coal and towards natural gas, nuclear and renewables, Virginia does not generate enough power to supply our current and growing need for power. The shortfall in power is supplied by PJM generation coming predominantly from West Virginia and Pennsylvania which are generating this excess power by coal and gas. During peak periods there may not be enough power to charge an EV overnight. 


from Dominion IRP 2023 update


Charging and range anxiety are the big day to day issues. The most obvious is the problem of charging EVs. I am not willing to plan my life around finding a charging station and waiting around for the battery to top up. During the Arctic blast last winter, we all watch the images of EV’s taking much longer to get a full charge or failing to charge all together in Chicago. Despite the IRA mandate to build a “convenient and equitable network” of 500,000 chargers to help make EVs accessible for both local and long-distance trips, I apparently live in the EV charging desert and would need to install a level II charger in my home to use an EV.  The only charging stations I know of is 8 miles from home or at the County Complex 26 miles away.

from Alternative Fuels Data Center: Alternative Fueling Station Locator (energy.gov)

While bigger batteries allow drivers to travel farther between charges and that has been the trend, they also make the cars heavier, more dangerous, more expensive, and more expensive to insure.  EV batteries aren't cheap and the bigger the battery the more expensive, reportedly costing up to $20,000 to replace. So effectively, the life of the batter is the life of the vehicle. It is widely reported that most EV batteries last between 10 and 20 years. The problem is the Tesla debuted in 2010 as did the Nissan leaf, so there is not a lot of real-world experience with this number. The lifetime of the vehicle is important to us, since we tend to keep our vehicles for their full lifetime. The difference between 10 and 20 years in a battery’s lifetime is huge in our cost of driving.

Battery chemistry, driving habits, environmental conditions and maintenance practices all affect EV battery life. My experience with phone and computer batteries is only a handful of years before they no longer hold a charge long enough to be effective tools. That is how batteries fail- they loose a little bit of their capacity each year.  An EV would require me to be a nursemaid to my battery. Keeping the EV away from extreme temperatures and not over charging the battery. EV’s  generally allow you to set the extent of the charge; Tesla recommends not to regularly charge the battery beyond 80% of the battery's capacity to maximize battery lifespan. The phone repair shop told me the same thing. Tesla says that charging to 100% is okay for long trips and is more convenient in those situations.

Insurance rates for EV's are also higher. The Wall Street Journal reported that the average repairable insurance claim for an EV was 30% higher than an equivalent internal combustion engine vehicle. Insurance rates on automobiles have also more than doubled in recent years and that makes the situation worse. I called my insurance company to check the price to insure a new EV and was simply shocked, though insuring any new vehicle is rather shocking. 

Total  EV’s in the Commonwealth (as of June 2024) were 78,694 out of 8.4 million cars- less than 1%.  At least right now we do not have the infrastructure to support this transition outside of Fairfax and Loudoun Counties and Richmond. It is not just the lack of charging stations, but the additional cost of the vehicle and  higher insurance. Also, my husband is concerned about fire. He does not want a massive lithium ion battery in a garage attached to ur house.  He still wants a fuel cell vehicle, and there are no fuel cell stations in the Commonwealth. I am not making blue hydrogen in the backyard though he suggested that might be a nice hobby for me. This does not look like our EV moment. 


Work was done a couple of years ago to calculate the emissions vehicle manufacturing and then the operational carbon footprints. On average the groups found that it takes about 40% more carbon dioxide emissions to manufacture an EV rather than an internal combustion vehicle.  In addition the carbon the batteries contain rare earth metals like cobalt and lithium. The mining process is hazardous to the environment and the workers especially in other countries. The batteries also have a large water footprint.  EVs produce no tailpipe emissions when they are used. No smog, no NOx, nothing to pollute the air. Gas cars produce a lot of tailpipe emissions. Overall it was calculated. it takes about 20,000-23,000 miles of driving to make up for the manufacturing deficit. For us that would be about 4 years of driving before the purchase of an EV would have a positive impact on our planet. We do have a newer and lower milage vehicle driven mostly locally (except recently as I hesitate to drive long distances in our old Acura)- though 10 years old it has around 40,000. The smaller vehicle may be our EV in the future. We'll see. 


Sunday, June 9, 2024

Help Fairfax Water identify Lead Lines


In 2021 the U.S. EPA revised  the Lead and Copper Rule to mandate that all water utilities plan to test for lead more frequently at schools and childcares, develop an inventory of the water service lines within their system, and create a plan to replace lead service lines if they are found. This fall is the deadline for the lead service line inventory. Fairfax Water has developed the “Lead Free Fairfax program” to comply with these requirements and keep the Fairfax community safe from lead in drinking water.  

Lead service lines are typically owned by both the water utility and the property owner. It is common that utilities only own the portion of the service line until it reaches the property line. In most instances Fairfax Water owns the portion of the lateral service line up to and including the water meter which is usually at the property edge. The property owner owns the portion of the service line after the meter as well as the home’s internal plumbing. However, most houses in Fairfax County built between 1971 and 1980 were equipped with an inside water meter, which is connected to a remote register on the exterior of the house. For more information read the Fairfax Water Lead and Copper Rule fact sheet.Fairfax Water Lead and Copper Rule fact sheet. 

Fairfax Water is updating its inventory of service line materials and working to identify any lead service lines within its water system. The inventory will be complete by October 2024 as required by the Lead and Copper rule regulations. To ensure customer safety, Fairfax Water uses corrosion control treatments to prevent lead from leaching into water from any lead containing elements in the distribution system or property owner plumbing.  

Much of the data collected  by Fairfax Water about the materials in the distribution system is based on the historical records and not confirmed or may need to be updated. Since a portion of the service line is not owned by Fairfax Water, they are trying to reach out to their customers to identify and report their service line material for the inventory.

To  do your part, go to the Fairfax Water inventory map and enter your address. See what information they have. Then you can update the information, or simply go to the shut off valve and scan the QR code with your smart phone or you can follow this link to fill out the inventory online LSLI SELF-ASSESSESMENT PUBLIC APP V2 (arcgis.com). If you have neither a smart phone nor online access, then call them with an old fashioned phone.


This is an important regulation because lead can cause damage to the brain and kidneys, and can interfere with the production of red blood cells that carry oxygen to all parts of your body. The greatest risk of lead exposure is to infants, young children, and pregnant women. Scientists have linked the effects of lead on the brain with lowered IQ in children. I am amongst the many scientist who believe there is no safe level of lead exposure. If your home was built before 1990 the only way to know for sure if you have lead in your drinking water is to test. You can get your water tested for lead by Fairfax Water by contacting Customer Service at (703) 698-5800. Test kits cost $40 for the first kit and $20 for every following kit should you wish to do any additional sampling. Once your order is processed, you will receive a test kit with instructions for how to take the water sample and return it to Fairfax Water for testing. 


The U. S. EPA limit for lead in drinking water is currently 15 parts per billion (ppb), but only requires action if limited sample monitoring for lead has exceeded the 15 ppb action level in more than 10% of the homes tested. Cities are only required to test a very small number of homes monthly and the condition and age of the plumbing in the home really determines if lead levels will be elevated. EPA estimates that there are 9.2 million lead service lines nationally.  

Lead in drinking water is a national problem mostly associated with older urban areas.  Lead in drinking water predominately comes from the pipes. Lead does not exist in most groundwater, rivers and lakes- the source water for most municipal and private water supplies. Instead, lead in drinking water is picked up from the pipes on its journey into a home.

In the early years of public water supply the water service lines delivering water from the water main in the street into each home were commonly made of lead. This practice began to fade by the 1950’s but was legal until 1988. Lead was also used to solder copper pipes together before 1988 (when the 1986 ban on lead in paint and solder went into effect). Also, until very recently (2011 Reduction of Lead in Drinking Water Act) almost all drinking water fixtures (faucets and such) were made from brass containing up to 8% lead, even if they were sold as "lead-free." So even homes built with PVC piping in the 2000’s may have some lead in most of the faucets.

Wednesday, June 5, 2024

Replacing Peat media in Puraflo and Eco-Flo Systems

It is estimated that about a third of homes in Virginia have septic systems. There are many different types of septic system designs. The most common type used for single family homes is still the traditional septic system that consists of a single chamber septic tank that flows by gravity to a drain/leach field. However, due to regulatory changes, continued growth in housing Alternative Onsite Sewage Systems (AOSS) have become popular.

A typical AOSS in Virginia consist of a septic tank, treatment unit, pump chamber, conveyance line, distribution system, and an absorption field (trenches, pad, drip tubing, etc.). However, the exact set of components that make up the system are site and system specific. AOSSs allow homes to be built on land that “does not perk”- can neither pass the standard percolation test nor support a traditional septic system.

To protects public health, the waters of the state and the environment AOSS are regulated in Virginia under 12VAC5-613-140. This regulation requires all AOSS are designed, meet minimum performance standards and will be properly maintained and inspected at least once a year with newer systems required to be sampled regularly. The full text of the regulations can be read at this link.

These non-conventional septic systems include: aerobic tank or ATU’s, peat filter systems, coir filter systems, single and recirculation sand filters, mound systems, drip dispersal, spray and low pressure dispersal. Manufacturers of these systems have gotten their systems approved in the commonwealth so that they can be bought off the shelf. These systems include but are not limited to: Advantex, Clearstream, Puraflo, EcoFlo, EZ Treat, Fujiclean, Microfast Norweco, Bio Coir. All of these systems are approved for use in Virginia, but may not be optimal for all sites and are also expensive to build, maintain and replace.All of these systems are approved foruse in Virginia, but may not be optimal for all sites and are also expensive tobuild, maintain and replace.

None of these AOSS systems is ideal, but I’ve always liked the simplicity of the peat filter systems and the peat is a phenomenal media for absorption. The peat media filter system is a traditional septic tank with peat filtration system instead of a leach field. The filtration system is the aerobic portion of the treatment and is located in tanks which are filled with peat moss over a gravel base. The filtered septic tank effluent is collected in the pump tank. A timed dosing system pumps the effluent through an inlet manifold located at the base of the treatment modules. An orifice plate is located inside the top of each inlet manifold which allows the flows to be split equally and fed simultaneously to each biofilter module or modules. (The number of modules is based on the size or type of the system-the number of bedrooms is how these systems get sized.) The inlet manifold is connected to the base of the biofilter module and is fed upwards to a rectangular distribution grid located 6 inches below the top of lid. The effluent percolates laterally and vertically through the depth of the peat fiber treatment media and emerges as a clear, innocuous liquid from the base of the system. The treated effluent is then collected and dispersed. New systems are installed with a sample port.

from EcoFlo

From Anua

The peat is an excellent media for allowing the natural secondary treatment of the sewage waste to take place: Absorption and filtration of any impurities chemical adsorption, and microbial assimilation. As a result, these systems are typically capable of removing 90% or more of the polluted mater (characterized as BOD, SS, Coli forms and E. Coli). The life of these systems varies by manufacturer and origin of the peat. For Puraflo systems, peat moss replacement is recommended around every 14 years. For Ecoflo systems they recommend that the peat should be replaced approximately every 7 years. These number assume that the system is properly used and maintained (or less with improper use). The required annual inspection of the system will determine when to replace the peat, and when to pump the tanks.

The problem is that the peat used in these systems came from Canada, Ireland, or other overseas location (depending on if you have a Puraflo or Ecoflo), and extraction and removal of the peat can impact natural ecosystems of those locations. Peat is a limited natural resource and as such expensive. Recently, the cost of replacing the peat media is $2,250-$3,010  per module for the Puraflo system (depending on the number of modules) and $5,200-$6,000 for the Ecoflo system. This pricing includes disposal of the existing peat and labor, but does not include the pump-out of the tanks which is necessary. This has gone up significantly since I last checked pricing. The Puraflo prices are down somewhat since the end of the pandemic. Ecoflo pricing went up during the pandemic and have stayed up.

There is another option. Puraflo has a new media, coir, coconut fiber. While Anua has a Bio-Coir system that is generally approved in Virginia, you can also use a coir media as a direct substitute for peat. Unfortunately, since this substitution of media has not been generally approved, it would require five rounds of 180 day sampling to prove it’s functioning, new spray nozzles and an engineer’s stamp on the design. (see the VHD memo.)(see the VHD memo.)

 The costs to change the media would be about the same as the costs for replacing the peat listed above, the first time. Though coir, which is coconut fiber, is low-cost and a renewable resource that gets consumed over time, the change from peat media includes disposal of the existing peat and changing of the spray nozzles to the ones designed specifically for the coir. Going forward the system would only require the addition of coir as needed, but that is a long term cost savings and many do not keep their homes long enough to benefit. Coir is a by-product of coconut harvesting and is a renewable resource.

The AOSS market in Virginia is dynamic. Things change and it is likely that steps that need to be taken to replace peat media with coir will evolve and become simpler. However,  for now though costs are still high.

Sunday, June 2, 2024

Envirothon State Winners


Jamestown High School, of James City County Schools, placed first overall in Virginia’s 2024 Dominion Energy Envirothon State Competition, held at Radford University on May 19th-20th, 2024. Jamestown competed with teams representing 18 different high schools throughout Virginia to earn the title of State Champions.  The 2019 team from the same high school was the overall International winner that year, so clearly Jamestown High School must have a terrific coach and great program! In 2023 the Jamestown team also won the Virginia state championship and placed 13th overall.

Envirothon is an international environmental and natural resources high school competition held annually. This year 53 teams of students from across the United States, Canada and China in a week-long competition demonstrated their knowledge on soils and land use, aquatic ecology, forestry and wildlife management through written tests and hands on interactive stations. The teams also prepared oral presentations on this year’s current issue, “Renewable Energy for a Sustainable Future” and teams presented solutions to address a renewable energy scenario for the Hampton Roads area of Virginia.

In Virginia the Envirothon is run by the Virginia Association of Soil and Water Conservation Districts and Virginia’s 47 local Soil and Water Conservation Districts. Each spring there are a series of regional competitions held by the Soil and Water Conservation Districts with help from our volunteers. For the last 11 years Dominion Energy has been the primary sponsor of Virginia’s local, regional and statewide Envirothon with annual funding provided by its Dominion Energy Charitable Foundation.

“Protecting the environment and supporting local communities are key components of our mission.” said Hunter A. Applewhite, president of the Dominion Energy Charitable Foundation. “Envirothon proudly promotes both as these students will become future leaders of environmental sustainability.”

The Jamestown High School team is supported locally by the Colonial Soil & Water Conservation District. In second place was Louisa County High School- the Thomas Jefferson SWCD team. In Third place was Eastern View High School- the Culpeper SWCD team. All these schools have excellent programs and many competitive teams over the years.

The Jamestown team will travel to Geneva, New York on July 28th-August 3rd, 2024 to represent Virginia as they compete at the National Conservation Foundation’s International Envirothon. At the International Competition the teams are given a special environmental problem in the morning then have five hours to work out the solution as a team. Join me in wishing the Jamestown High School team good luck.


Wednesday, May 29, 2024

What You Should Know About Septic Before You Buy that House

 It is estimated that about a third of the homes in Virginia have septic systems. Virginia is a "buyer beware" state. Any well,  groundwater or septic problems not detected by the buyer during the sale process become the  home buyer's problem upon closing the sale. There is no legal recourse back to the seller. Period.

Before you purchase a house, Virginia Tech recommends that buyers should engage a licensed well contractor to assess the well and a licensed septic installer/service company to assess the septic system. As part of the assessment, the home buyer should obtain a copy of the "Water Well Completion Report" and the septic system (or AOSS) repair/permit history and the history of septic tank pump-outs. This information is on file at the local health department. Home inspections do not cover septic and well systems. The average lifespan of a septic system is 15 to 40 years, but it can last longer if properly maintained. A traditional septic system should be inspected every three to five years (and pumped out at that frequency) by a septic system service provider; and an alternative septic system (called an AOSS) must be inspected at least every year in Virginia.

There are two basic types of septic systems: a conventional septic system and an AOSS or Alternative septic system. AOSS stands for Alternative Onsite Sewage System.  A typical septic system has four main components: a pipe from the home, a septic tank, a gravity or pumped conveyance of the septic tank effluent to the drain field

conventional septic system from EPA

A typical AOSS in Virginia consist of a sewer line, septic tank, treatment unit, pump chamber, conveyance line, distribution system, and absorption field (trenches, pad, drip tubing, etc.). If there are a lot of mechanical components its probably an AOSS.


An AOSS ATU tank from EPA 

The septic tank is a buried, watertight container typically made of concrete, fiberglass, or polyethylene. It holds the wastewater long enough to allow solids to settle out (forming sludge) and oil and grease to float to the surface (as scum). The septic tank also allows partial decomposition (by natural bacterial action) of the solid fecal matter. Compartments and a T-shaped outlet in the septic tank are intended to prevent the sludge and scum from leaving the tank and traveling into the leach field area. Some newer systems have screens and filters to keep solids from entering the leach field, but older systems typically do not. These filters and screens can become clogged and need to be cleaned out regularly to prevent septic sludge from backing up into the house.

two chamber septic tank from EPA

When you look at a house, look for the septic tank. The tank should not be entirely buried and at least one port should be visible in the yard. If the tank is entirely buried- move on, do not buy the house because it is a safe bet that the tank has never been pumped, the system is old and the entire septic system will have to be replaced.  The solids, scum and grease that accumulate in the septic tank need to be pumped out and disposed of every few years. If not removed, these solids will eventually overflow the septic tank, accumulate in the drain field, and clog the pores in the soil and the openings in the pipes. While some clogging of soil pores occurs slowly even in a properly functioning system, excess solids from a poorly maintained tank or a tank where enzyme additives were used instead of pumping the tank can completely close all soil pores so that no wastewater can flow into the soil.

The sewage effluent will then either back up into the house, flow across the ground surface over the drain field, or find another area of release in the septic system. In some cases where the drain field has become clogged and no longer can adequately absorb the wastewater, the toilets and sinks might not drain freely. A black residue may remain at the bottom of the toilet.  If the drain field can absorb the effluent, but no longer treat it, the sewage may contaminate the groundwater or surface water with fecal coliform bacteria. On a dry day if there is a soggy area of the yard the drainfield may already be failing.

Since 2011 all AOSS in Virginia must be inspected at least once a year and the septic tank pumped as needed this is generally ever 2-5 years. In addition, “AOSS are required to be operated, maintained and inspected by a Licensed Professional. Licensed AOSS Operators are regulated by the Department of Professional and Occupational Regulation (DPOR).” This generally means that the homeowner will have a single year or multiple year contract with a licensed septic company and there will be annual notations of inspection at the County Department of Health.

Some counties in Virgina were better than others at keeping records in the early years, but these days, there is a statewide online system that licensed operators can access to enter the inspections. In 2022, the General Assembly approved legislation (HB 769) that took effect on July 1, 2023, and includes a requirement for maintenance providers to report pump-outs within the Eastern Shore and Three Rivers health districts using a web-based reporting system developed by VDH.  To implement this reporting tool, VDH made changes to the existing MyHD platform.  While the legislation specifically identifies the two health districts as a pilot program, the MyHD portal accepts pump-out reports and other maintenance information from licensed/permitted providers from across the Commonwealth and has become the default.

Virginia Department of Health (VDH) regulates onsite (septic) sewage treatment systems in Virginia. While only owners of AOSS are required to be inspected annually, VDH recommends that the more common conventional septic systems should be inspected and/or pumped every 3-5 years. This preventative maintenance can extend the life of the septic system and reduce nitrogen pollution into nearby waters. Below is a short video with all the EPA septic quick tips. It is under 3 minutes.



is 


Sunday, May 26, 2024

Green Infrastructure is not Preserving our Essential Watersheds

There seems to be a huge misunderstand in some department of Prince William County that “green infrastructure” can substitute for maintaining natural open space and not developing more than 5%-10% of the Occoquan Watershed to preserve our essential water resources and the source water for the Occoquan Reservoir. This is not true. Green infrastructure emphasizes design elements to manage stormwater and enhance urban environments. Natural open space is essential to preserve existing ecosystems-our essential Occoquan Watershed.

Traditional "gray" stormwater infrastructure is designed to move urban stormwater away from the built environment and includes curbs, gutters, drains, piping, and collection systems. Generally, traditional gray infrastructure collects and conveys stormwater from impervious surfaces, such as roadways, parking lots and rooftops, into a series of piping that ultimately discharges untreated stormwater into a local water body.  This would indeed be disastrous to our local drinking water supply. “Green" stormwater infrastructure is designed to mimic nature and slow stormwater movement. Trying to capture rainwater where it falls in stormwater ponds or slowing the velocity of stormwater with some natural elements. Green infrastructure reduces and somewhat treats stormwater to reduce localized flooding, reduce the costs of stormwater infrastructure, and improve aesthetics.  

Though, “green” infrastructure solutions can be applied on different scales. On the local level, green infrastructure practices include rain gardens, permeable pavements, green roofs, infiltration planters, trees, and tree boxes, and rainwater harvesting systems.  Generally, it does not reduce the impact of urban sprawl and impervious surfaces on the groundwater that is an essential element of our hydrology and  water supply. Changing the use of the land, covering it with buildings, driveways, roads, walkway will reduce groundwater recharge in the surrounding area increasing stormwater runoff velocity and quantity.

Only at the largest scale, the preservation and restoration of natural landscapes (such as forests, floodplains, and wetlands) is it possible to restore the function of the land. Prince William Forest Park which took over a hundred years to restore from monoculture agriculture to an Eastern Piedmont forest may be an example. There is a huge difference between letting a forest reclaim agricultural fields and trying to restore urbanized land. There is no example of restoration of land from urbanization back to forest.

Changing land use from open land either forest or agriculture can reduce the water supply over time. Many studies have found that an increase in impervious surface reduces base flow to our rivers and streams. This is because impervious surfaces prevent infiltration, thereby reducing groundwater recharge and base flow. As groundwater levels fall, perennial streams that feed the rivers become ephemeral. The groundwater becomes disconnected from the surface water network.

No study has found that green infrastructure prevents this from happening. The quantity of impervious surfaces, those surfaces that prohibit the infiltration of water from the land surface into the underlying soil, turns out to be the most critical indicator for analyzing impacts of urbanization on the water environment. Once the hydrology is destroyed by development, it cannot be restored. 

In the Water Infrastructure Improvement Act, of 2019,  green infrastructure is defined as "the range of measures that use plant or soil systems, permeable pavement or other permeable surfaces or substrates, stormwater harvest and reuse, or landscaping to store, infiltrate, or evapotranspirate stormwater and reduce flows to sewer systems or to surface waters." Though the principals are related to maintaining a functioning watershed, these steps are inadequate to preserved a functioning watershed as the impervious surfaces expand beyond 10%. Stream quality degrades and can only be slowed, but not stopped by green infrastructure.

Impervious surface increases the frequency and intensity of downstream runoff and decreases water quality. Increasing urbanization has resulted in increased amounts of impervious surfaces - roads, parking lots, roof tops, and so on - and a decrease in the amount of forested lands, wetlands, and other forms of open space that absorb and clean storm water in the natural system. This change in the impervious-pervious surface balance has caused significant changes to both the quality and quantity of the storm water runoff, leading to degraded stream and watershed systems.

Furthermore several studies have documented that the quantity of impervious surfaces is directly related to the water quality of a watershed- the drainage basin and it’s receiving streams, lakes, and ponds. Increase in impervious cover and runoff directly impact the transport of non-point source pollutants including pathogens, nutrients, toxic contaminants, and sediment. Impervious surfaces also collect and accumulate pollutants that are deposited on roadways and other impervious surfaces  from the atmosphere, leaked from vehicles or derived from other point sources. During storms, accumulated pollutants are quickly washed off these surfaces and rapidly delivered to aquatic systems. As the area under impervious cover increases, more water reaches the Chesapeake Bay and ocean as surface water run-off. Stormwater runoff picks up pollutants as it flows across land surfaces. Pollutants include sediment, pesticides, asphalt, fertilizers, bacteria and other disease-causing organisms from failing septic systems; petroleum products such as oil and grease.

Finally, the areal extent of impervious surfaces may significantly influence urban climate by altering the sensible and latent heat fluxes within the urban areas as was found in the study of temperature variation study in Westmoreland County . Areas with a large amount of impervious surfaces are also susceptible to  higher ambient air temperatures because the man made roads, parking lots, concrete surfaces and buildings absorb and trap more heat than natural environments. Plants use the energy of the sun while man made surfaces absorb and radiate the energy of the sun. These clustering of heat absorbing manmade surfaces and structures create Urban Heat Islands that can impact a community’s environment and quality of life increasing energy consumption for cooling, increase emissions of air pollutants and greenhouse gases, and impaired water quality.

Using 320 air temperature measurements at 20 sample sites on July 10, 2022 and the Random Forest model in ArcGIS Pro they were able to extrapolate temperatures across the region, ultimately identifying non-heat islands, heat islands, and urban heat islands. The data found that 3.57% of the landmass of the region (approximately 32,700 acres) was an EPA classified urban heat island.  The heat island results were clustered in Fredericksburg and surrounding areas. The variation was found to be a  17-degree Fahrenheit difference from forestland temperatures and heat island.

Wednesday, May 22, 2024

Direct and Indirect Use of Water in Data Center Industry

Data centers directly and indirectly use water; however, they also have significant impacts on watersheds and the hydrologic cycle replacing natural open space with 7-8 football fields of building surrounded by cleared, compacted and paved land. Data centers also deliver contaminants into our waters.

We all know that data centers use huge amounts of electricity to power their millions upon millions of chips. One data center can require 50 times the electricity of a typical office building, according to the U.S. Department of Energy. That electricity has a water footprint.

The electric power sector uses a large amount of water, primarily for cooling (though there is hydroelectric use. In Virginia we use hydroelectric for power storage. The Bath County Pumped Storage Station uses two reservoirs to create a hydroelectric power storage battery which is reportedly the largest battery in the world with a maximum generation capacity of 3,003 MW and a total storage capacity of 24,000 MWh.

The most significant use of water is in power generation. Thermoelectric power plants (including natural gas, nuclear, and coal plants) boil water to create steam, which spins a turbine to generate electricity. The steam leaving the turbine must be cooled back into water to be used to generate more electricity. Plants withdraw water from nearby rivers, lakes, or oceans and pass that water through the steam leaving the turbine. That process cools and condenses the steam back into water, but a certain amount evaporates. In 2021, 73% of the utility-scale electricity generated in the United States came from thermoelectric power plants.

The electric sector’s water-withdrawal intensity—the amount of water withdrawn per unit of electricity generated—depends on the power generation mix and technology used. It has been falling as we move away from coal since natural gas uses less water. Nationally, water used in power generation was 11,595 gal/MWh in 2021.

While the Virginia power mix has been migrating away from coal and towards natural gas, nuclear and renewables, Virginia does not generate enough power to supply our current and growing need for power. The shortfall in power is supplied by PJM generation coming predominantly from West Virginia and Pennsylvania. 

Dominion Energy in Virginia predicts that by 2035 the data center industry in Virginia will require 11,000 megawatts from them, nearly quadruple what it needed in 2022, or enough to power 8.8 million homes. Northern Virginia Electric Cooperative recently told PJM that the more than 50 data centers it serves account for 59% percent of its energy demand. It expects to need to serve about 110 more data centers by July 2028.

Data centers also use large amounts of water directly for cooling systems, which ensure that the heat produced by these massive facilities is controlled.Data Centers are cooled using either air conditioning (electricity) or evaporative cooling (water). Evaporative cooling is more efficient and effective. 

In a water-cooled system, water-cooled chillers and cooling towers located on top of the data center roofs produce chilled water, which is delivered to computer room air conditioners for cooling the entire building. Some of this water can be recycled through the system more than once.

So, how much water do data centers use,. The industry treats it as a trade secret. In 2021, when Prince William County looked at water consumption for its 25 operational data centers at the time it found that water use varied by season and ranged from about 0.2 to 0.5 gallons per square foot per day. Of course, the total square footage of the data centers was not disclosed. The data centers that Prince William looked at were all relatively small 100,00-250,000 square feet- nothing like the hyper centers being built now. Today, data centers seem to start at a million square feet and move up from there with multiple building campuses.  How water use scales up in multi-story data centers is unknown. The heat island effect is likely to increase water needs for cooling.

Loudoun County has a larger data set. Loudoun County built a reclaimed water system to supply data centers more cheaply with water. However the expansion of data centers required more than that system could provide. The water from the Broad Run Waste Water Treatment plant was inadequate to serve all data centers.


from Loudoun Water ICPRB presentation data centers that they know about

According to Loudoun County, Data center water use will have grown to an average 4 million gallons a day of potable water and 4 million gallons a day of reclaimed water by the end of this year- since in northern Virginia we drink the reclaimed water from UOSA and returned upstream to the Potomac, that is enough water to supply 100,000 people. 

As reflected in the Loudoun Water data, some of the data centers do reuse water by recirculating the same water through their cooling systems multiple times while replenishing what evaporates. According to Google, this practice saves up to 50% of water when compared with “once-through” cooling systems. However, eventually this reused water needs to be replaced with new water, due to mineral scale formation which could damage the cooling equipment or once the conductivity of the water is too high which could damage the IT equipment.

The need for new water results from the build-up of calcium, magnesium, iron, silica, and salt which become concentrated by evaporative cooling cycles. The amount of water data centers consume also fluctuates based on seasonal weather conditions. Facilities typically use less water during the winter months and more during the summer months as can be seen in the potable water data from Loudoun County.

Data center wastewater is largely comprised of blowdown; the portion of cooling water removed from circulation and replaced with freshwater to prevent excessive concentration of undesirable components like salt can the concentrated impurities. In general data centers recycle their water until the concentration of dissolved solids (which is essentially salts) is roughly five times the supplied water. This blowdown is sent to the waste water treatment plant which is not designed to remove salts. This exacerbates the problem of salinization that is a  growing problem in our region and water resources.

In Loudoun the reclaimed water distribution system in Ashburn receives reclaimed water from Loudoun Water helping to save money.  Purchasing  reclaimed water is cheaper than purchasing an equal amount of potable drinking water. To provide the reclaimed/ recycled water, Loudoun uses the effluent water from the Board Run wastewater treatment facility near Ashburn. That water is ultimately returned to the Potomac River, saltier than it started upstream from the Leesburg, Fairfax Water and Washington Aqueduct intakes for their drinking water treatment plants.

from Loudoun Water presentation to ICPRB

Loudoun Water tracking potable water use for data centers requires the data centers to self identify, which does not always happen. The reclaimed system needs a direct hookup, so that is easier to track. Overall, there is believe to be 51 million square feet of data centers operating in Northern Virginia at the end of 2023. Combining all the estimates and allowing for air cooled facilities, that is enough water for between 150,000-375,000 people.  CBRE estimates that 3-4 times that amount of data centers are currently under construction. 

Prince William county believes that most data center water comes from potable water supplies. Though Amazon has a permit to withdraw upto 2.5 million gallons of water a day from groundwater wells it has in Manassas, most data centers in Virginia are not required to permit and monitor their water use.  In Prince William County the treated sewage from UOSA is already used by Fairfax Water (upto 40 millions gallons a day) to supplement water supply to the Occoquan Reservoir for our drinking water supply.

Though we do not generally think of it that way, a data center is an industrial use, not a commercial use in its need for square footage and power with a very large carbon footprint, diesel generators and fuel storage tanks treated under regulations as separate sources of above ground fuel storage and potential release. The actual buildout of the physical properties of data canters is also impacting the availability of and quality of water. Impacting to future sustainability and availability of water for our region.