Wind Power Transmission Project Would Save Natural Resources

Guest Blog | March 3, 2015 | Energy Policy, Wind
Plains and Eastern Clean Line Land Usage estimates, based on conservative estimates from the Department of Energy Environmental Impact Statement

This blog is part of a series reviewing the proposed Plains and Eastern Clean Line project. Other blogs in the series are available here.

The Plains and Eastern Clean Line, a newly proposed high voltage direct current (HVDC) transmission project that would provide about 4,000 megawatts of high-quality Oklahoma/Texas wind power to Arkansas and Tennessee, is currently undergoing federal environmental review. As part of the federal process, the U.S. Department of Energy has drafted an Environmental Impact Statement to evaluate potential environmental harm and benefits for the project.

The project spans over 720 miles from western Oklahoma, across Arkansas and to its end point in Shelby County, Tennessee. Any project that large is bound to have an impact on the environment, so the real question is how big is the environmental impact, and do its environmental benefits outweigh the impacts? Perhaps the biggest negative impact the project would have is associated with its terrestrial impacts; however, these impacts are relatively small compared to the project benefits and other sources of power.

In order to determine impacts to the land, the Department of Energy evaluated agricultural resourcesgeology, soils and mineralsvegetation communities and land use. The majority of the acreage affected by Clean Line will be affected in the construction phase, and later returned to other uses. For example, wind turbines only use about 1% of the land that wind farms occupy – leaving 99% of the land for farming or other usage. Clean Line will compensate land owners for land use by the HVDC project. In total, the HVDC project is anticipated to disturb up to 2,670 acres, split between Oklahoma, Arkansas, and Tennessee (approximately 90% from access roads), while the corresponding wind farms would disturb between 2,164 and 3,246 acres split between Oklahoma and Texas. In the Department of Energy’s terms, “There would be no irreversible or irretrievable commitment of agricultural resources,” indicating many of the “used” acres could be eventually returned to production.

To be sure, these quantities of land sound substantial; however, the numbers need to be put into context. Listed below are individual parts of the Plains and Eastern Clean Line project, with the quantity of acres disturbed associated with each part, as well as some more commonplace comparisons.

Fiber Regeneration – 2 acres – Less than two football fields

AC Collector System – Between 1.8 to 7.8 acres – Less than a small elementary school complex

Each Converter Station – Between 40 to 60 acres – Roughly the size of two Wal-Mart stores

HVDC Towers – Between 5 to 86 acres – About the size of Memorial Park in Bentonville, Arkansas. The range is based on a best case scenario using monopoles (5 acres), or a worst case scenario using lattice towers (86 acres).

Access Roads – 2,394 acres – Slightly larger than the Northwest Arkansas Regional Airport (XNA)

Wind Farms – Between 2,164 to 3,246 acres – Two to three average farms in Texas County, Oklahoma (where one of the converter stations will be located)

In total, the 5,916 acres associated with the Plains and Eastern Clean Line project, and affiliated wind farms, represents a maximum of 9.25 square miles, or about the size of the city of Grove in Northeastern Oklahoma. Grove is located next to the 46,500 acre, man-made Grand Lake O’ the Cherokees. The Grand River Dam Authority (GRDA) built a 120 megawatt hydroelectric dam on Grand River to create the lake. The lake is currently inundating approximately 7.8 times more land, with a nameplate power capacity of only 3% of the proposed Clean Line project.

Compared to other threats to land use, the Clean Line project uses a relatively small amount of land. According to the Farmland Information Center, nearly 2.5 million acres of rural land was lost to development nationwide from 2007-2010. That’s a loss of about 0.2% out of the nearly 1.4 billion acres of rural land. According to the National Resources Inventory by the U.S. Department of Agriculture, the United States loses about an acre of agricultural land every minute.  Additionally, every year, about 7-11 million acres of cropland fails or is abandoned. That’s about 3-5% of all cropland. Specifically in Arkansas, Oklahoma, Tennessee and Texas, about 122,000 acres of agricultural land are lost annually across the four states due to development.

While the Plains and Eastern Clean Line project will use land (indeed, any manmade structure does), this project may actually help reduce natural resource usage overall. As noted in the EIS, the project would likely displace other forms of energy usage, like coal or natural gas powered generation. Over the 80 year lifespan of the project, it is estimated that Clean Line will help deliver about 1.6 billion megawatt hours of wind power. In order to generate an equivalent amount of power, coal-fired power plants would consume a total of about 92,143 acres (144 square miles) of coal-filled railroad cars (not including required track, engines, coal mines, coal-fired power plants, coal ash ponds, surface water, transmission or other associated infrastructure). Natural gas power plants would need about 12.6 trillion cubic feet of natural gas to generate an equivalent amount of power of the Clean Line project. That quantity of natural gas, if liquified (condensed) and placed in liquid natural gas (LNG) rail tank cars, would result in 99,360 acres (155 square miles) of LNG-filled rail tank cars (not including required track, engines, gas wells and pads, gas-fired power plants, transmission or other associated infrastructure). And while wind power would use substantially less land than fossil fuels, wind energy also has none of the associated harmful air emissions, water consumption or other negative environmental impacts.

These figures are not academic.

The Bureau of Land Management, a federal agency that oversees the nation’s forests, is planning on leasing some 6,000 acres of national forest for the Green Hollow coal mine in Utah. The mine could extract some 56.6 million tons of coal over its lifetime, which could theoretically generate about 104 million megawatt hours of electricity. That’s about 93% less electricity than wind turbines connected to the Plains and Eastern Clean Line – for a similar amount of land area. Given the option between a wind power transmission line and a coal mine, it’s clear which option is sustainable, and which is not.

Given that Clean Line’s one-time-use of 5,916 acres is a very small portion of rural land development, many of the acres used can ultimately be returned to production, the project footprint is smaller than other forms of existing power generation, and that the clean wind power produced can offset the negative effects that other energy resources have on natural resources and public health, it’s clear the Plains and Eastern Clean Line project is a net benefit to land and natural resource conservation.

The Department of Energy is taking public comment on the Plains and Eastern Clean Line project until March 19th, 2015. If, after reading this blog, you would like to submit a public comment supporting the project, click here.

This blog is part of a series reviewing the proposed Plains and Eastern Clean Line project (PECLseries).

Coal Equations

1 ton = 1,842 kilowatt hours (1.842 megawatt hours)

Clean Line generation = 4,550 MW * 50% CF * 8,765.8 hours/yr * 80 years = 1,595,375,600 megawatt hours

1,595,375,600 MWh (Clean Line) / 1.842 MWh (coal) = 866,110,532 tons of coal to replace Clean Line

866,110,532 tons of coal / 121 tons per train car * 53 feet per car = 379,370,728 feet / 5,280 feet per mile = 71,850 miles

379,370,728 feet * 10.58 feet train width = 4,013,742,311 square feet of coal railroad cars / 43,560 square feet per acre = 92,143 acres of coal railroad cars / 80 years = 1,152 acres of coal railroad cars annually

Gas Equations

1,000 cubic feet gas = 127 kilowatt hours (0.127 megawatt hours)

1,595,375,600 MWh (Clean Line) / 0.127 MWh (gas) = 12,562,012,598 MCF (gas) * 1,000 cf per MCf = 12,562,012,598,000 cubic feet of gas to replace Clean Line

12,562,012,598,000 cubic feet of gas / 2,534,168 cf per rail tank car, liquid natural gas = 4,957,056 LNG rail tank cars

LNG Rail Tank Car square feet, area = 873.1 sq. feet (Length = 81.83 feet; Width = 10.67 feet)

4,957,056 LNG rail tank cars * 873.1 sq. feet / 43,560 sq. ft. per acre = 99,360 acres / 640 acre per sq. mile = 155 sq. miles

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