By Peter Montague, Environmental Research Foundation

The PurGen application to the New Jersey Department of Environmental Protection (DEP) for an air permit offer us some valuable insights into the proposed coal plant. (A PDF copy of the air permit can be found here: page numbers within this memo refer to pages in that PDF document.)

The 750 megawatt power plant will send “up to 450 MW [megawatts] of electrical power to the PJM Interconnect* market.” (pg. 9) (PJM Interconnection is an electricity wholesaler that serves New Jersey but not New York.) This means that 300 megawatts (or 40%) of PurGen’s 750 megawatts will be doing something besides generating electricity.

The 300 megawatts will be doing two things: powering the carbon sequestration apparatus, and making nitrogen fertilizer (urea) for sale.
“Purgen will use 2.55 million tons of coal per year. Of this, 40% will be mined, shipped and processed each year for purposes other than making electricity … powering the carbon sequestration apparatus and making nitrogen fertilizer for sale.”

Purgen will use 7000 tons of coal per day (pg. 9). (Pg. 10 says Purgen will use 40,000 tons of coal every 5 days, which is 8000 tons per day. In this memo, I’ll use the lower figure, 7000 tons per day.)

At 7000 tons per day, Purgen will use 2.55 million tons of coal per year. Of this, 40%, or one million tons of coal (in round numbers), will be mined, shipped and processed each year for purposes other than making electricity.

On pg. 17 we learn that Purgen will produce 40,000 tons of urea every 11 days, or 1.3 million tons per year. Urea is the most nitrogen-rich fertilizer in common use (it’s 46.7% nitrogen), and it currently sells for about $500 per ton, thus bringing Purgen $650 million per year. (See Table 7 at http://goo.gl/3blT)

According to U.S. Department of Agriculture, the U.S. used 5.7 million tons of urea in 2007 (see Table 4 at http://goo.gl/3blT). So PurGen’s annual urea production will be large — 23% of annual U.S. urea use.

Nitrogen is an unusual element. It makes up 78% of the atmosphere, yet in the air it is inert, meaning that is does not combine chemically with other substances. Two natural agents “fix” atmospheric nitrogen into chemically reactive forms — lightning and bacteria in soils. See http://goo.gl/zRxB

Plants and animals require chemically-reactive nitrogen for their metabolism, eventually returning it to the atmosphere. As early as 1970 scientists expressed concern that humans were interfering with the global nitrogen cycle on a massive scale[1] — humans were fixing the same amount as natural processes — thus doubling the amount of reactive nitrogen cycling through the biosphere.
“Nitrogen is creating “dead zones” in the world’s oceans, and killing corals, among other negative effects.”

Since 1970, human production of reactive nitrogen has continued to grow, and scientific concern about the consequences has grown apace. In September 2009, a group of European scientists described nine ecological “boundaries” that they believe humans must not transgress. Of the nine, three have been transgessed already — and one of these three is human use of nitrogen fertilizers. See http://goo.gl/NGeN and http://goo.gl/8iwK and http://goo.gl/l9NF.

This group of scientists calculated that human use of reactive nitrogen must be cut to one-quarter of where it is today, in order to achieve a sustainable level of use. http://goo.gl/8iwK

Thus the PurGen coal plant will be manufacturing 1.3 million tons of a fertilizer that ecologists tell us is already ruining the biosphere (the parts of the planet that inhabited by living things). Nitrogen is creating “dead zones” in the world’s oceans, and killing corals, among other negative effects.

One might argue that making more electricity is a good thing, but it is hard to argue that making more reactive nitrogen fertilizer is a good thing. The biosphere is already being degraded by reactive nitrogen fertilizer and cannot tolerate more.

Urea has the chemical formula CH4N2O. After it is spread onto agricultural land, urea hydrolyses into ammonia and carbon dioxide — thus reducing PurGen’s overall carbon capture and sequestration efficiency. We need quantify this aspect of Purgen’s urea production to learn the extent to which it will prevent Purgen from achieving its goal of capturing 90% of its CO2 emissions.

Economically, Purgen is really a fertilizer factory that also produces some electricity, rather than an electric power plant that also produces some fertilizer.

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[1] Carroll L. Wilson and others. Man’s Impact on the Global Environment; Assessment and Recommendations for Action. Cambridge, Mass.: MIT Press, 1970. See, for example, Table 2.3 on pg. 116.

This article was first published on March 15, 2010.