Energy research at Berkeley Lab

At Berkeley Lab, the energy challenge has captured the imagination of some of our very best scientists. We are mounting a major, multidisciplinary initiative to create sustainable, carbon-neutral sources of energy. This effort seeks to understand the fundamental mechanisms in organic and inorganic energy conversion that will serve as the foundation for technology developments in the environmentally responsible production and conversion of renewable resources for fuels, chemicals, and other energy-enriched products. Berkeley Lab brings a unique combination of research strengths to bear on the energy problem.

Helios: A new facility proposal for solar energy research

A future cornerstone of the Berkeley Lab energy initiative is The Helios Project, a new energy/nano research building that would be central to one of our major scientific initiatives: The conversion of solar energy into carbon-neutral form of energy that could sustain our world in an environmentally friendly manner. Named after the Greek god of the sun, Helios is poised to address one of the most important societal problems that science and technology can help solve. Berkeley Lab, with its broad spectrum of expertise and its history of team collaborations, is ideally positioned to address this challenge.

The Helios Project proposal, led by Laboratory Associate Director Paul Alivisatos and Physical Biosciences Director Jay Keasling, will cut across divisions and programs in profound ways to produce transforming technologies in synthetic biology and nanotechnology, and will fuse our core strengths in biological, chemical, and physical sciences in the search for a sustainable carbon-neutral source of energy. Now is the time to consider how new research at the interface of basic energy sciences and applied fields of energy technology can increase our future energy options. A well-conceived program put in place now has the potential to provide the people of the United States with renewable energy security and economic growth in the decades to come. 

Synthetic biology: Biologically inspired systems for biomass-to-fuel and solar-to-chemical solutions

Biomass, mankind’s long-standing energy source, has the potential of supplying
significant amounts of renewable energy if efficiencies for the conversion to fuels can be
substantially improved. Corn-to-ethanol is perhaps the most touted biomass energy solution, but it the current conversion process actually consumes more fossil energy than it creates, while creating substantial water and air pollution. Meanwhile, cellulose, the largest available biomass, resource remains untapped. A more direct photosynthetic biomass solution - direct solar hydrogen from cyanobacteria and green algae - is currently limited by the low light-to-fuel efficiency of these natural systems. To address these problems, synthetic biologists are now looking at these research areas:

• Engineering organisms to produce fertilizers on-site, especially photosynthetic nitrogen fixation in the form of ammonia. This will improve the energy balance for corn to fuel by avoiding the large fossil fuel consumption by conventional manufacturing processes and fertilizer transportation. More sustainable sources of phosphorous would have to be found.
  
  
• Engineering novel metabolic pathways for the conversion of cellulose to fuel (ethanol, methanol, methane, hydrogen). Possible approaches include the design of an organism with an artificial chromosome that incorporates the relevant features of the cellulose degrading machinery.
  
  
• Engineering of green algae and cyanobacteria with improved photosynthesis rates, and on-site coupling of hydrogen production to catalytic conversion to carbon-based fuels are important targets.
  
  
• Biologically-inspired synthetic catalysts for key bond forming and breaking steps for fuel formation and interconversion of various forms of fuels. Enhancement of the stability and increase of the rates compared to natural catalysts through synthetic modification and use of nanostructured catalyst supports is an important goal. Development of efficient methods for coupling of catalysts to electron or hole source, and embedding in robust nanostructured supports for enhanced stability are crucial tasks.

Engineered systems: Hybrid nanomaterials and biomimetic systems for solar-to-fuel conversion

Artificial photosynthetic devices for solar-to-fuel conversion offer the potential of robust and
efficient systems not limited by the constraints of living organisms. Two major challenges need to be met in order to achieve this goal. One area is biomimetic catalysts that accomplish organism-like multi-electron transformations (such as H2O oxidation to O2 or CO2 reduction to a carbon-based liquid fuel) but at much higher, robust rates compared to natural systems. Of the few existing engineered catalysts that accomplish such transformations, some require noble metals whose insufficient abundance precludes their use in a large scale energy economy, and almost all are driven by stoichiometric reagents rather than by visible light. Progress is hindered by a lack of understanding of the bond making/breaking steps and coupled proton and electron transfer events at catalytic sites. A second major challenge is bio-inspired supramolecular assemblies that afford optimum coupling of light-harvesting, charge migration, and catalytic components for efficient fuel formation. With these two challenges in mind, Berkeley Lab scientists are considering these primary research areas:

• Development of synthetic catalysts with abundant low Z metals (Mn, Fe, Co, Ni, Cu, Zn) for the splitting of water, reduction of CO2 to formic acid and ultimately to methanol, or for the formation of halogens from hydrogen halides. Key aspects are multi-electron transfer capability and control of proton and electron transfer, the design of which will benefit greatly from insights gained by structural and mechanistic studies of biological catalysts.
  
  
• Exploration of methods for increasing the durability of biomimetic catalysts, such as encapsulation or anchoring on inorganic supports and establishing mechanisms for self repair.
  
  
• Exploration of organic or biological/organic 3-D hybrid structures for integration and optimal organization of the photoactive and catalytic moieties, taking architectural design principles of nature as a guide.
  
  
• Exploration of light-driven generation of ion gradients across membranes as a solar energy storage mode that can be exploited in such bio-inspired supramolecular assemblies, requiring the development of synthetic proton pumps.

Nanomaterials and nanostructured assemblies for photochemical conversion
(solar-to-electric and solar-to-fuel conversion)

The emergence of nanotechnology and the rapid advances in the development of novel
nanoscale and nanostructured materials has opened up unprecedented opportunities to
overcome long-standing obstacles toward efficient conversion of solar light to electricity
and fuels. However, major obstacles include: the efficient absorption of photons from the full solar spectrum; the durability of light harvesting and fuel forming sites, and of supports for the
vectorial arrangement of the various components; efficient contacts between photoactive
charge-transfer components and catalytic sites; spatial separation of the chemical products generated at oxidizing and reducing sites to prevent efficiencydegrading back or cross reactions; and materials suitable for inexpensive fabrication and processing of solar to electric or solar to fuel assemblies on a very large scale.

Berkeley Lab recognizes the need to launch a concerted effort advance nanoscience and technology in solving these challenges. In particular, novel approaches by nanostructured materials should be explored to control the fundamental processes such as absorption of light and the density of photon, electron and phonon states to maximize the use of solar radiation. New types of nanomaterials need to be engineered that minimize the loss of charge, particularly in the promising area of metal oxide and metal sulfide semiconductor systems. 3-D inorganic or organic/inorganic hybrid nanostructures should be explored to control the transport of chemicals in photosynthetic systems to avoid loss by cross reactions, and to achieve integration of the functional components with precise arrangement for optimal coupling. Such materials might offer strategies that will enhance robustness through recycling of degraded organic components during operation.

Nanoscale engineering needs to be developed for improved charge contacts at interfaces and between surfaces and molecular components, including biological functionalities on inorganic supports. This is an important prerequisite for the integration of multi-electron transfer catalysts into nanoscale materials. Effort should focus on exploiting nanotechnology for designing solar to electric or fuel device fabrication that resembles plastic manufacturing.

Photoelectrochemistry

The lack of efficient multi-electron transfer catalysts for water oxidation and proton or CO2 reduction is the single most critical challenge of efficient photoelectrochemical fuels generation (methanol, methane, hydrogen). Whether considering photovoltaic coupled to electrochemical devices or photoactive electrodes of photoelectrochemical cells, the performance of all existing
systems is limited by the inefficiency of the fuel forming transformations at the electrodes. There is a need for the design of engineered enzymes that catalyze the above redox reactions at the appropriate potential and at substantially higher turnover rates compared to natural catalysts. Another important engineering aspect is improved stability over the biological systems. The effort requires a close collaboration between chemical biologists and inorganic and materials chemists.

Berkeley Lab - a unique blend of research strengths

Led by Berkeley Lab Director Steve Chu's conviction that we can and need to tackle this problem now, our unique combination of strengths in many of these areas positions it to mount the kind of large-scale, interdisciplinary research effort that the energy problem calls for. Our hope is that some of the most rapidly advancing areas in science, such as nanotechnology and synthetic biology, will transform industries, enabled by world-class facilities like Berkeley Lab's Molecular Foundry, now under construction, and the new Berkeley West Biocenter. Government and industry investment -- as well as immense public support -- is needed to drive the nationwide quest to secure our energy future.