An Energy Lab Notebook

October / November 05 Volume 3 Number 5

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TRANSPORTATION

Finding Lighter Materials
Almost half of all new vehicles sold in the United States are pickups, sport utility vehicles and vans. On average, they weigh more than cars, are less fuel-efficient and present safety problems when they collide with lighter vehicles. Because these vehicles also consume the most fuel, the use of lightweight materials is expected to improve their fuel economy.
Lightweight materials and manufacturing technologies also may play an important role in President Bush's FreedomCAR program, which emphasizes a long-range shift from a fossil fuel-based transportation economy to a hydrogen-based transportation economy that uses fuel cells rather than combustion engines. But to maximize driving range and performance, hydrogen fuel-cell vehicles will have to be as light as possible.
"The new focus on hydrogen means an even stronger, more urgent need for lightweight vehicles. We are redoubling our efforts in the materials sector to lighten the load to maximize hydrogen's benefits," said Mark Smith, manager of PNNL's energy materials group.
Glass, which accounts for about 100 pounds on the average family sedan, is another focus. PNNL and its automotive and glass manufacturing partners have developed a prototype windshield that is 30 percent lighter than current windshields and retains key optical, thermal and safety properties. Additional glass research is focusing side and rear windows and on special coatings, such as those that reflect infrared rays.

Greater Engine Efficiency
Livermore engineers are exploring an innovative engine concept, Homogeneous Charge Compression Ignition (HCCI) that promises to operate at high efficiency (greater than 40 per cent) with low nitrogen oxide and particulate-matter emissions. In an HCCI engine, the fuel is premixed with air, as in a spark-ignited engine, but in a very "lean" mixture that has a high proportion of air to fuel. When the piston reaches its highest point, the fuel autoignites from compression, as in a diesel engine. The HCCI engine burns cooler than spark-ignited and diesel engines, and its lower combustion temperature considerably reduces the emissions of nitrogen oxide. In addition, premixed combustion in HCCI engines reduces particulate matter emissions to very low levels. An HCCI engine can operate using any fuel, so long as the fuel can be vaporized and mixed with air before ignition. The Livermore team projects that a stationary HCCI engine will be available for commercialization in the next five years.

Vehicle Aerodynamics
For every mile on the freeway, the average-size American car has to push 5.5 metric tons of air out of its way. Overcoming this aerodynamic drag takes a lot of energy. At 70 miles an hour, as much as 65 percent of the fuel the car uses goes to overcoming air resistance. The numbers are similar for big-rig tractor-trailers, despite their far greater weight, and even higher for high-speed trains. Livermore is leading a DOE project to examine possible ways to make heavy trucks more aerodynamic, reducing air resistance and thus increasing fuel efficiency. Engineers estimate that truck drag coefficients could be reduced by as much as 25 percent over the next 20 years. In the future, such a reduction would save billions of liters of diesel fuel annually—€”as much as 12 percent of the fuel used.

HYDROGEN AND FUEL CELLS

Vehicle Hydrogen Storage
Livermore researchers have developed a "hybrid" hydrogen fuel storage system that could ultimately replace gasoline-powered engines in cars and trucks. Hydrogen fueled vehicles are more efficient and cleaner than gasoline or diesel vehicles. In addition, production of hydrogen from carbon-free sources, such as nuclear or renewable energy, is one of the most efficient and economical ways to achieve deep cuts in carbon dioxide emissions. The team focused on overcoming one of the major barriers to practical hydrogen-fueled vehicles: onboard storage. The researchers have developed and are testing a safe, compact hydrogen storage tank that combines the around-town energy efficiency of conventional compressed hydrogen gas with the long-distance driving range of cryogenic (low-temperature) compressed gaseous and liquid hydrogen.
And at Sandia, there's a virtual Center of Excellence for the development of reversible metal hydrides materials. A key objective is the development of a class of materials capable of storing hydrogen safely and economically aboard a vehicle that can run for at least 300 miles before refueling. The center includes four other national laboratories, eight universities and three industrial companies. The center will undertake $30 million of R&D over the next five years.
In a collaboration independent of the center, Sandia and General Motors have launched a partnership to design and test an advanced method for storing hydrogen based on the metal hydrides. Metal hydrides—€”formed when metal alloys are combined with hydrogen—€”can absorb and store hydrogen within their structures. When subjected to heat, the hydrides release their hydrogen. In a fuel-cell system, the hydrogen can then be combined with oxygen to produce electricity. GM and Sandia have embarked on a 4-year, $10-million program to develop and test solid-state tanks that store more hydrogen onboard a fuel-cell vehicle than current conventional hydrogen storage methods.

Auxiliary Power Units
PNNL is working on lightweight materials, emission-reduction technologies and fuel-cell technologies, including developing solid oxide fuel cells for auxiliary power units in vehicles.
Fuel cells could provide exactly as much power as long-haul trucks need to sustain their "hotel load." With the help of a fuel cell, a truck's refrigeration unit, lights, heat or air conditioning for the cab, a power source for computers and cell phones, and other power devices could operate during rest stops without the engine running. Today, truckers run a 600-horsepower engine to provide the few kilowatts they need during stops. Due to concerns about truck emissions, there is pending legislation that would prohibit trucks from idling on the side of the road. Fuel cells could be a solution.
Researchers are working on ways to put fuel reformers onboard vehicles so various kinds of fuel, including diesel, could be converted into the hydrogen gas needed to operate a fuel cell.
Converting Methanol
Los Alamos recently added to its extensive fuel cell patent portfolio. In March of this year, inventors Mahlon Wilson and John Ramsey were awarded U.S. Patent 6,864,004 for their Direct Methanol Fuel Cell Stack. The Wilson-Ramsey fuel cell is a 12-cell stack design that provides a substantial increase in average cell current density over previous designs, with an overall power density of 80 watts per kg. Direct methanol fuel cells convert methanol into electricity, CO2 and water.

NUCLEAR

Energy and National Security
To regain U.S. leadership in the energy field, an integrated energy, nuclear leadership and national security policy must be developed, recognizing interrelationships among all aspects of nuclear energy and national security. The "Global Nuclear Future" is a Sandia vision, now shared by many others, about how nuclear energy can meet needs for domestic energy security, global national security, nonproliferation and nuclear materials management. In nuclear safety, Sandia's blend of modeling, analytical and experimental capabilities, combined with expertise in risk assessment for nuclear power plants, has it in a lead position with the Nuclear Regulatory Commission on a variety of projects in reactor safety, including fire risk, severe accident modeling, human factors analysis, risk assessment applications, analysis of containment and storage casks, spent nuclear fuel transport and vulnerability assessment for reactors, fuel cycle facilities and spent fuel.
In nuclear materials transportation Sandia demonstrated a wireless instrumentation system, which couples power and data, allowing instrumentation of sealed containment vessels for nuclear materials.
Producing Low-Enriched Uranium,
Tennessee Valley Authority and DOE accomplished a significant milestone this spring when fuel fabricated from down-blended surplus DOE weapons-grade materials was loaded into the Browns Ferry nuclear power plant in Athens, Ala.
The collaborative effort among TVA, DOE and public and private enterprise involves blending highly enriched uranium from DOE sources to produce blended low-enriched uranium, or "BLEU" fuel, for use in TVA's nuclear plants. Removal of the material located at Y‑12 is an important factor in Y‑12's modernization efforts.
"Converting this material to reactor fuel is, by far, the lowest-cost option for dealing with the material," said Dale Davis, manager of the Off-Specification Fuel Program for BWXT Y-12's Highly Enriched Uranium Disposition Office. "Storing it or disposing of it as waste are both very expensive options. Down blending it and burning it as fuel in power reactors eliminates its use for weapons, lowers costs and provides a benefit to the public."
This is the first of several BLEU reloads scheduled for Browns Ferry. The program will eliminate more than 39 metric tons of highly enriched uranium. When blended down to produce fuel for a commercial nuclear power reactor, this material could provide electricity to every household in the U.S. for approximately three months.

Spent Fuel Treatment
A nuclear power plant generates electricity primarily from the fission of uranium-235 and plutonium-239. As the fuel is consumed fissile isotopes deplete, and fission products that absorb neutrons build up. However, spent fuel contains substantial amounts of energy in the remaining "ashes." Los Alamos's goal is to separate the spent fuel into packages, thereby recovering energy economically and safely.
LANL has developed a crystallization process for recovering uranium, neptunium and plutonium from spent fuel dissolved in nitric acid. LANL is also evaluating an approach to separate actinides from fission products in spent fuel based on aqueous carbonate solutions.

CLIMATE CHANGE

Carbon Management
The deep ocean is the largest potential CO2 reservoir accessible from the Earth's surface. It is thought that engineering changes in micro-nutrient iron supply to oceanic plankton could significantly lower concentrations of atmospheric CO2. Implementing large-scale iron fertilization to alleviate greenhouse gas is fast approaching economic viability. To understand the potential rewards and risks, Los Alamos has been developing a detailed ocean biogeochemistry computer model. This model includes many nutrients, tracers and other metrics that influence the carbon cycle.

Reducing Diesel Emissions
While diesel engines are more efficient than gasoline engines, they pose different challenges. Diesel engines run lean, meaning there is excess air in the exhaust. In those conditions, different catalysts are needed to reduce oxides of nitrogen and particulate matter emissions. Almost every technology for reducing emissions decreases fuel efficiency, but the goal is to reduce emissions without a "fuel penalty." PNNL researchers are working with engine manufacturers and catalyst suppliers to develop new systems that will help industry meet future emission standards.

Carbon Sequestration
Carbon sequestration—€”also called CO2 capture and storage (CCS)—€”is an important way to significantly reduce greenhouse gas emissions. Livermore's research in carbon sequestration encompasses the four main approaches to CCS: geological storage, ocean storage, terrestrial storage and advanced concepts such as mineralization or biological mimicry (biomimetics). In geological storage, LLNL's efforts include programs to understand and predict the fate of subsurface CO2 injections using advanced, integrated reactive transport computer models, which have been used in the world's largest CO2 storage project, the mammoth Sleipner project in the Norwegian North Sea and are planned to be deployed at the Teapot Dome national carbon storage test center in Wyoming.

EFFICIENCY AND CONSERVATION

Reducing Energy in Computing
Energy consumption is the largest recurring cost in a typical computer datacenter. To help reduce energy use in high-performance computing, Los Alamos has recently made available its EnergyFit software. EnergyFit minimizes the energy produced by individual CPUs in a cluster or server farm and can dramatically reduce the overall energy consumption in a datacenter. On a high-end system, EnergyFit typically delivers system energy savings of 10 to 25 percent with a minimal performance reduction of less than 5 percent.

FOSSIL FUELS

Coal
Los Alamos has developed a process to improve the efficiency of power production by explicitly integrating the separation and capture of CO2. This process, the zero-emission coal process, reuses waste heat and includes a lime-CO2 separation step. LANL's zero-emission coal process has very high theoretical efficiencies (averaging 70 percent in one independent evaluation) in purifying CO2. Potential applications of LANL's work include coal-compatible fuel cells, novel trace-element clean-up cycles and CO2 mineralization.

Oil
At the average U.S. oil site, about 60 percent of the oil remains in the ground after primary production. Seismic stimulation—€”low-amplitude, low-frequency seismic stress waves—€”can improve oil flow dramatically. Before 1992, field tests in the Soviet Union indicated that seismic stimulation could increase oil production rates by 50 percent or more. While seismic stimulation has great potential, results have varied from field to field, and engineers cannot yet predict where seismic stimulation will work and where it will not. The mechanisms involved in seismic stimulation must be far better understood.
Los Alamos has designed and built a laboratory facility that allows the quantification of dynamic stress effects on multi-phase fluid flow during bench-top experiments on porous core samples. The capabilities of this facility are believed to be unique in the world. Via experiments performed at its Core Stimulation Facility, LANL is beginning to identify possible guidelines for where and how to apply seismic stimulation effectively.

As drilling reaches deeper and deeper to tap new gas and oil reserves, Sandia is borrowing from and improving upon high-temperature drilling technologies developed in the geothermal industry. This effort involves bit design improvements, down-hole electronics, diagnostics-while-drilling technologies and broadband borehole telemetry systems.
Sandia and petroleum explorationists in Southeast New Mexico and West Texas have teamed on a three-year project to develop geophysical mapping and computer simulation tools to identify new reserves on the Central Basin Platform. A Texas study estimates potential reserves in the area as high as five billion barrels. The relatively small and deeply buried reserves are not detectable by conventional seismic techniques.

Natural Gas
Over the last two decades ocean exploration has uncovered a new fuel source—€”methane hydrates. Methane hydrates are usually found in ocean sediments on the sea floor of continental shelves or slopes at a depth range of 350 m to 1200 m. The molecular structure is similar to ice except a methane molecule is trapped within the hexagon ice cage. When methane hydrates dissociate because of either lowering pressure or rising temperature, the methane gas escapes, and the ice cage melts. The chemical energy stored in methane hydrates is estimated to be twice that of all other fossil fuels combined. Los Alamos is working on a viable strategy to use methane hydrates as a fuel source. The general proprietary design is a "closed system" where no pollution byproducts will be emitted from the fuel cycle. The laboratory anticipates looking for partners interested in engineering design studies in the near future.

FUSION

Energy From the Sun
The sun and stars constantly generate magnetized plasmas. Solar flares, for example, are magnetized plasmas that separate from the sun and bombard the Earth and other planets with a magnetic field large enough to interfere with communication systems. The magnetized plasmas in Livermore's Sustained Spheromak Physics Experiment (SSPX) represent one possible route to a source of fusion energy—€”the virtually unlimited, non-polluting energy that powers the sun. The SSPX plasmas are much smaller and far shorter-lived than their celestial cousins, but the two varieties share many of the same properties. Magnetic fields pass through flowing plasma and eventually touch one another and reconnect. When a reconnection occurs, it generates more plasma current and changes the direction of the magnetic fields to confine the plasma. This "self-organizing" dynamo is a physical state that the plasma forms naturally. If a self-organizing plasma can be made hot enough and sustained for long enough to put out more energy than was required to create it, the plasma could prove to be a source of fusion energy.