June 12, 2015
Less traditional efforts to harness the power that fuels the sun are making progress.
In the most basic fusion reaction, molecules of hydrogen isotopes are smashed together under high temperature and pressure to create helium — with part of the hydrogen mass converted into energy, in accordance with E=mc² from Albert Einstein's theory of relativity. The energy payoff can be immense, as demonstrated by the sun's glare. But can the reaction be controlled on Earth?
Lawrence Livermore and University of Washington researchers say it’s possible. Their plan calls for scaling up the university's sheared-flow stabilized Z-pinch experiment — a device that could be built up into a commercial fusion reactor.
When it comes to the increase in energy use in the United States, natural gas is the winner.
The U.S. used more total energy in 2014 than in any year since the great recession, but a shifting mix of sources for that energy meant that carbon emissions were down from 2010 levels, according to a study and flow chart released recently by Lawrence Livermore National Laboratory.
A.J. Simon, the Laboratory's energy group leader, says that this reduction in carbon emissions can be attributed to a combination of the emergence of wind energy and a greater acceptance of natural gas for electricity generation and industrial applications. "It's mostly wind — and a little solar — that accounts for maybe one-third to half of the emission reductions that we've seen," says Simon, who notes that although solar is growing much more quickly, there is far more wind power.
"The other big [factor] is that the low price of natural gas has encouraged a lot of power producers to move away from burning coal to generate electricity [to using] natural gas to generate electricity. Natural gas, in the best of scenarios, releases about half the amount of carbon dioxide as coal when used to produce electricity," Simon notes.
When the National Nuclear Security Administration built the National Ignition Facility (NIF) at Lawrence Livermore, its major selling point to the public was to explore nuclear fusion reactions as a possible new energy source. The other reason was to perform experiments in another area: nuclear weapons research.
The U.S. stopped nuclear weapons testing in 1992. Since then, personnel charged with ensuring the safety and reliability of the U.S. stockpile have relied on old testing data, continued experiments that fall short of actual weapons conditions and computer modeling. NIF began to contribute to plutonium science this year, six years after the facility was completed.
“The focus of the experiments that we’re doing at NIF is to develop a better understanding of the material properties of plutonium in conditions that are relevant to nuclear weapons,” said Michael Dunning, principal deputy for Weapons and Complex Integration at LLNL.
The studies at NIF are necessary because plutonium has unique properties that can’t be predicted by comparisons with other elements.
Hui Chen, a physicist fromLawrence Livermore National Laboratory, and her colleagues are confident they could re-create galactic events such as gamma-ray bursts (GRB) and supernovae when the technology is available.
Using some of the most powerful lasers around, the team fired a laser beam at a sheet of gold foil and watched what popped out. The gold atoms produced a pair of particles when energized by the laser: one matter electron and one antimatter positron. Antimatter has similar properties to matter, but the electric charge is the opposite. So, a matter particle that is negative (e.g. electron) will have an antimatter partner particle that has the same mass but is positive (e.g. positron). A matter/antimatter collision creates so much energy that you can see high-energy gamma rays, and Chen's laboratory has created nearly a trillion particle pairs using this method.
The method that the laser beam uses to create matter/antimatter pairs is common to one of the universe’s most energetic events: a gamma-ray burst. GRBs are a powerful explosion of energy that is emitted from extremely massive, energetic stellar objects, like black holes or exploding stars.
Suzanne Singer works as an energy thermal fluids analyst at Lawrence Livermore National Laboratory. Her main passion is in solar forecasting, which helps predict how much energy the panels in a solar farm will produce.
Singer's other focus is using her research to reach out to Native American tribes around the country.
“One thing I'm passionate about is to help tribes become more sustainable using their own resources and intellectual capacity.” Singer said. “The interactions between culture and energy and the environment are very important.”
She also encourages students on tribal reservations to become involved in energy research and even follow a STEM career path.