Saturday, February 26, 2011

Post # 28: Environmental Stewardship and Sustainable Energy

The spring flowers are just beginning to peep through the brown over-burden of Winter-killed vegetation here in East Tennessee.  Spring is a wonderful time of year to be out and about in the mountains and river valleys of this beautiful region of the country.  Seeing the awakenings of Spring always starts me to thinking about our responsibilities as stewards of God's Creation.  And being a good steward of the environment, while addressing the every-growing energy needs of a world seeking the quality of life enjoyed by those of us in the West is an ever-growing challenge.  That's one reason I'm such a strong supporter of nuclear power.

Nuclear power generates ~ 17% of the world's electrical energy while generating lower carbon dioxide emissions per MW-hr of energy than any other energy form except hydro power (and there are some estimates that indicate it's actually lower than everything except run-or-the-river or "kinetic" hydro power.)  If one is concerned about the amount of carbon emitted by energy production, one has to look positively on nuclear power.

Nuclear power is a frugal user of land - generating the highest energy production per acre of land used (or conversely using the least land per unit of energy produced) of any energy production resource - even when uranium mining is considered.  I recently ran across a fascinating paper from on this subject entitled   "Energy Sprawl or Energy Efficiency: Climate Policy Impacts on Natural Habitat for the United States of America," by Robert I. McDonald, Joseph Fargione, Joe Kiesecker,William M. Miller, Jimmie Powell.  It can be found at

Here's a quote from the paper relating to land-use intensity of energy production:

The land-use intensity of different energy production techniques (i.e., the inverse of power density [16],[17]), as measured in km2 of impacted land in 2030 per terawatt-hour per year, varies over three orders of magnitude (Fig. 3). Nuclear power (1.9–2.8 km2/TW hr/yr), coal (2.5–17.0 km2/TW hr/yr) and geothermal (1.0–13.9 km2/TW hr/yr) are the most compact by this metric. Conversely, biofuels (e.g., for corn ethanol 320–375 km2/TW hr/yr) and biomass burning of energy crops for electricity (433–654 km2/TW hr/yr) take the most space per unit power. Most renewable energy production techniques, like wind and solar power, have intermediate values of this metric.

So there you have it.  If one is concerned about land "consumed" in the production of electrical energy (along with associated issues such as human and biological population displacement and habitat destruction), one has to look positively on nuclear power.

An then there is water usage.  Water usage is a challenge for all large central generation power plants.  Presently, there are two dominant approaches to cooling both fossil and nuclear power plants.  The "once-through" cooling approach "borrows" water from the river or reservoir that serves as the cooling water source.  This water is heated as it cools the plant.  About 99% of the water is returned back to the river.  Federal and state regulations set limits on the allowable warming of the river or lake from which the water is drawn.  The second major approach to cooling power plants utilizes "wet cooling tower".  This approach consumes twice as much water as the once through cooling approach, and a larger volume of this water is actually "consumed" in the process (i.e. the net water lost from the river or reservoir is greater.)

According to the Nuclear Energy Institute, "Nuclear energy consumes 400 gallons/MWh with once-through cooling and 720 gallons/MWh with wet cooling towers.  Coal consumes less, ranging from about 300 gallons/MWh for plants with minimal pollution controls and once-thorough cooling to 714 gallons/MWh for plants with advanced pollution control systems and wet cooling towers.  Natural gas-fueld plants consume even less, at 100 gallons/MWh for once-through, 370 gallons/MWh for combined cycle plants with cooling towers, and non for dry cooling."  To put this in perspective, "a typical nulcear power plant supplies 740,000 homes with all of the electricity they use while consuming 13 gallons of water per day per household in a once-through cooling system, and 23 gallons per day per household in a wet cooling tower system.  By comparison, the average U.S. household of three people consumes about 94 gallons of water per day."   (Nuclear Energy Institute @ )

So,  water usage issue is actually one of the most complicated and challenging issues in energy production - especially for large nuclear and fossil-powered plants.  The reason for this complication is the numerous ways in which water is used at different points in the energy production supply chain for different energy production technologies (fossil, nuclear, solar, geothermal, etc.)  We can and we should do better.  New technology and new approaches to water management show promise for improving this picture.  This "energy – water nexus" will be subject of a future post.

Just thinking ...


Friday, February 18, 2011

Post # 27: Rare Earths, E-Waste, China, and Sustainability

China announced this past December it will curtail its 2011 export quota for rare earths by 35%.

See for example,

What are "rare earths", and why should the Sustainability Community care?

Rare earths are a group of seventeen elements that are essential in the production of a wide variety of electrical components and clean energy technologies.  They are found in Group 3 of the periodic table, and have names like gallium, europium, samarium, and thorium.  These rare earths are used in the manufacture of iPods, flat-screen TV's and computer monitors, high performance magnets, wind turbines, and a wide range of other consumer and industrial electronics.

China currently supplies 97% of the worlds annual rare earth demand.  The U.S. doesn't have a single active rare earth mine in production though we do have significant deposits that could be mined.  China's actions have some of the U.S.'s top strategic planners so worried, the U.S. has threatened action with the World Trade Organization to force China to loosen it's grip on this strategic material.

What's all this have to do with electronic waste or "e-waste"?

According to the U.S. Environmental Protection Agency, ( ), the U.S. discarded 1.5 – 1.8 million TONS of electronic waste in our landfills in 2005.  During that same year, we recycled less than 380,000 tons of surplus electronics.  The problem: as these discarded materials breakdown in the landfill, they release their stores of lead, mercury and other hazardous ingredients into the environment,

A typical personal computer contains economically recoverable quantities of gold, silver, copper, and palladium, and there are a number of firms that specialize in recovering these materials.  But what about the rare earths?  These electronics also contain significant quantities of rare earths – although at considerably lower concentrations that the aforementioned precious metals.  Well, it appears economically-competitive methods for recovering rare earths from e-waste are just becoming available.  According to press reports, Dowa, a Japanese mining company, recently began recovering rare earths from e-waste.  Research continues on many fronts, and major improvements are needed if these rare earth recovery technologies are to be widely deployed.  See for example: .

So here we see another strategic sustainability issue buried in today's headlines.  Rare earths are essential strategic materials for our national and energy security.  China has the world market cornered.  The U.S. (and the rest of the world) is annually discarding a mother-load of these materials and creating a significant environmental hazard in the process.  What's wrong with this picture?

Though I can't go into the details here, there are a variety of interesting options for improving this picture and a number of provocative questions one can ask.  Why isn't the U.S. mining our own resources?  What are the most promising avenues of research into improved rare earth recovery technologies?  How can we reduce our dependence on rare earths?  What can we do to move away from our "throw-away" consumer electronics culture?  How would massive "cloud computing" paradigms influence the production and generation of e-waste?

President Obama announced a new E-Waste Task Force in November to tackle some of the problems I mention here: ).

Let's wish them luck.  We all have a stake in their success.


Saturday, February 12, 2011

Post # 26: Building Energy Use - A Major Sustainable Energy Challenge

We recently replaced thirteen windows in our thirty year old home with high-efficiency Energy Star-rated windows.  Wow - what a difference over those thirty-year-old wood-sashed windows!  We actually saw a non-trival drop in our residential heating bill the first month despite it being the coldest month of the year.  This inspired me to revisit the data on building energy uses in the U.S.

Building energy usage is the single largest consumer of primary energy in the U.S.  According to the DOE 2009 Buildings Energy Book (found at ), residential and commercial buildings are responsible for ~ 40% (100 quads) of total U.S. primary energy consumption.  (The Industrial and Transportation Sectors consumed ~ 32% and 28% respectively.)  The DOE data also break down the 2006 building energy usage data to reveal the specific sources of this energy usage:
  • 19.8% Space Heating
  • 17.7% Lighting
  • 12.7% Space Cooling
  • 9.6% Water Heating
  • 7.8% Electronics
  • 5.8% Refrigeration
These six uses account for just over 73% of the total energy consumed by our residential and commercial buildings.

These statistics prompted me to wonder how difficult it will be to significantly reduce total building energy consumption.

The most convenient opportunity to positively impact residential and commercial energy consumption is in the construction of new buildings.  A new build offers the opportunity to integrate modern energy-efficient technologies in a way that simply isn't possible with an existing building.  I found an enlightening presentation by S. Shyam Sunder of the National Institute of Standards and Technology entitled, "Building Energy Efficiency – Net-Zero Energy, High-Performance Green Buildings" ( ) that addresses this issue.  Sunder points out that the replacement rate of building stock in the U.S. is only ~1% per year, and that the majority of current building energy efficiency retrofits target only the 5% of our buildings (commercial and residential) that are categorized as "large" buildings.  With only a 1% replacement rate in buildings,  I have to conclude we simply cannot look to new buildings as the solution to our building energy consumption challenge.

By the way, I also ran across a dandy little residential buildings fact sheet from the University of Michigan's Center for Sustainable Systems ( ) that indicates the average residential area per person grew from 292 sq. ft. in 1950, to 850 sq. ft. in 2000 – almost a factor of three!  Wow... that's something to think about.

Anyway, where do these facts leave us?  The answer: WE NEED A BREAKTHROUGH IN AFFORDABLE,  RETRO-FITTABLE ENERGY CONSERVATION TECHNOLOGIES FOR EXISTING BUILDINGS.  Otherwise it will be almost impossible to dramatically impact the total building energy usage in the U.S. in the lifetime of anyone reading these words.

The bad news is (going back to the building energy usage splits cited above),  there's no one "silver bullet" that will accomplish a transformational reduction in building energy usage given the diversity of building energy loads.  The good news is that even small improvements are magnified by the "law of large numbers" – the fact we have so many buildings to which any given improvement can be applied.

So..., as I've said in the past, I believe the recipe for a sustainable energy future has four key ingredients:
  1. Energy Conservation - everywhere and in everything, but especially in buildings
  2. Nuclear Power for central station electricity generation - supplemented as we can with all other clean energy sources
  3. A Fortified Electric Grid
  4. Electric Vehicles (private and mass transit).

Go to run for now...

Tuesday, February 8, 2011

Post # 25: Great Book on Nuclear Proliferation

Yesterday I introduced the topic of nuclear power and its relationship to nuclear proliferation.  For those of you who are interested in a great read on the history of nuclear proliferation, I highly recommend Thomas Reed's and Danny Stillman's book, "The Nuclear Express", published in 2009.  It's a rear page-turner.  Should be in the library of everyone who's interested in the subject...


Monday, February 7, 2011

Post # 24: Imperative 5 – Decoupling Nuclear Energy and Nuclear Proliferation

I apologize for the recent hiatus in my postings here.  I've been in a transition in my day job and it has definitely put a crimp in my blogging... Hopefully I'll be a little more consistent in the coming months...

My recent postings have focused on the Five Imperatives of Nuclear Power.  Now it's time for the Fifth Imperative:  Assure the deployment of nuclear power does not result in the proliferation of nuclear weapons.

This topic has been a subject of heated debate since the inception of commercial nuclear power in the 1950's and early 1960's.  President Eisenhower faced this challenge during his "Atoms For Peace" campaign.

It is widely understood there are three paths to attaining nuclear weapons.  The proliferating entity can either attain the uranium enrichment capability needed to produce weapons-grade uranium;  attain the nuclear fuel, reactor, and nuclear fuel reprocessing capability needed to produce weapons-grade plutonium; or simply steal the required uranium or plutonium.  History suggests both production paths have been successfully deployed by proliferating entities.  As far as we know, no one has stolen sufficient material to become a member of the nuclear weapons club.

I will have additional postings on this topic in the future.  The subject I want to address here is the often-used term "proliferation risk".  I don't like the term because I feel it is technically imprecise at best, and terribly mis-leading at worst.

The term "risk" has a precise engineering definition.  It is the sum, over all event paths and outcomes, of the product of the probability of a contributing event, and the consequence of that event.

Risk = Summation over all events of (Event Probability X Event Consequence).

We talk about the risk of smoking as "expected cancer deaths" or "expected cancers".  If someone wishes to discuss the "risk of an automobile accident", one must first define the term "automobile accident",  all of the accidents of interest, all of the events that lead to these accidents, and the probabilities of each of these events.

The first problem with apply this risk terminology to nuclear proliferation is that no on has ever been able to precisely define "proliferation" beyond simply "obtaining a nuclear weapon".  In order to usefully apply the risk equation, one must be able to deconvolve "proliferation" into its constitute chain of events.   Is enriching a gram of uranium "proliferation"?  Is losing a gram of uranium or plutonium "proliferation"?  Loosing 1 kg ?  Think about all of the events that must occur for uranium ore in the ground to become uranium in a weapon.  Get the point?

The second stumbling block in applying the risk equation to nuclear proliferation is the "probability" of "proliferation" is almost completely dominated by human will and intent.  Indeed, there are two components of this probability:  the probability someone will attempt to divert a technology, and the probability they will succeed in doing so.  In practice, advocates of the "proliferation risk" vocabulary typically assume the magnitude of the first "probability" is unity (1.0), and then move on to the rest of the story – often without any useful definition of the chain of events under consideration.

It is true some technologies are easier to divert for clandestine purposes that others. And it is possible to build technical barriers and "self-reporting" technologies into nuclear fuels, reactors, and reprocessing facilities.   But given an infinitely evil, infinitely rich, infinitely intelligent, and infinitely wealthy adversary, it's probably impossible to design a system that is "proliferation-proof".  (And of course, the other challenge is that many of the technologies that enhance the proliferation resistance of nuclear technologies also make them more expensive for legitimate energy production purposes.)

So, enough musings for this posting.  The topic of nuclear power and proliferation is very complicated, and men and women of good will can disagree strongly on many aspects of the debate.