Remarks by
Dr. Raymond L. Orbach
Director, Office of Science
U.S. Department of Energy

Science and Technology for Human Security Panel
102-E1
Second Annual Science and Technology in Society (STS) Forum
Kyoto, Japan
September 11, 2005

The world’s energy appetite will at least double by the end of this century (some claim it will triple). For most constrained CO2 concentration scenarios (550 – 650 oom), the amount of carbon-free energy required at the end of this century will more or less equal the earth’s total energy consumption at the beginning of this century.

Estimated total primary world energy consumption (terawatts), needed new non-CO2-emitting power to stabilize three atmospheric concentrations, and a conservative estimate of fusion power, as a function of time from the year 2000 to 2200.

The world therefore has a two-fold problem: where will this new energy come from, and how can it be net carbon-free? The most optimistic estimates of carbon-free renewable energy capability are a maximum of 17% of today’s energy consumption. Even with this very optimistic estimate, where will the remaining 83% come from?

There are other consequences of an energy hungry world. The hunger is of a different origin than in the 1970’s. Then it was energy supply – today it is energy demand (private communication, Jack Jacometti, Shell International Gas). We are already seeing the precursors of energy conflict. Consternation in the U.S. greeted a Chinese bid for UNOCAL. Japan has challenged China in gas exploration efforts in the East China sea. India and China, as their economies mature and expand, are already competing for energy sources for their billion people populations.

A global search for massive amounts of carbon-free energy will require transformational changes and disruptive technologies in order to provide clean reliable economic solutions.1 We cannot fulfill the world’s energy appetite with current prospects or incremental improvement to existing technologies.

What are the approaches that lead to these transformational technologies? How can they be made global so as to satisfy the new major energy consumers?

There are three points of departure:

1. Increase conservation, largely through increased efficiency.
2. Greatly diversify energy sources and create infrastructures for them.
3. Create and implement long-term (decades to century) energy visions and strategies.

More simply, increase conservation/efficiency and increase production. We must use less energy and produce more of it.

1. Increase conservation, largely through increased efficiency.

The United States is a prime example. Electricity production uses about 40% of primary energy, and of this amount, about 70% is waste or rejected energy. Overall, about 60% of United States primary energy is lost in waste or rejected heat. With less than 5% of the world’s population, the United States consumes about 25% of the world’s energy (but produces only about 18%). Even if the United States were to be 100% efficient in the use of energy, this would amount to but 15% of world energy consumption, not negligible, but far less than the doubling to tripling of the world’s energy generation required by the end of this century. Nevertheless, when amplified globally, more efficient use of energy can play a major role as part of a scenario to avoid energy conflict.

2. Greatly diversify energy sources and create infrastructures for them.

There are at least four transformational technologies that possess the potential for significant amounts of clean reliable economic energy: a. solar energy utilization; b. advanced proliferation-resisitant nuclear energy systems; c. fusion power; and d. biologically derived fuels.

a. The first is solar energy utilization: i. solar-to-electric, ii. Solar-to-fuels, and iii. Solar-to-thermal conversions.2 Sunlight provides by far the largest of all carbon-neutral energy sources. More energy from sunlight strikes the earth in one hour than all the energy consumed on our planet in a year. Yet solar electricity provides less than 0.1% of the total electricity supply, and renewable biomass (sustainably grown) provides thas than 0.1% of total energy consumed.

i. Solar-to-electric. Novel approaches exploiting new technologies (thin films, organic semiconductors, dye sensitization, and quantum dots) offer fascinating opportunities for cheaper, more efficient, longer lasting systems.

ii. Solar-to-fuels. Application of revolutionary advances in biology and biotechnology to the design of plants and organisms can lead to more efficient energy conversion “machines”. Designs of highly efficient, artificial, molecular- level energy conversion machines, exploiting the principles of natural photosynthesis, promise substantial energy production opportunities.

iii. Solar-to-thermal. Solar radiation as a source of heat, using high-efficiency thermoelectric and thermal photovoltaic converters coupled to solar concentrators, have the potential to generate electricity at converter efficiencies of 25% to 35%. Chemical conversion sequences can convert focused solar thermal energy into chemical fuel.

b. The second is advanced, proliferation resistant, nuclear energy systems. Current “once through” nuclear reactor policy leaves spent fuel rods with long term heat loads and radioactive decay. Disposal of light water reactor waste must be included as a cost factor for energy generation from nuclear fission sources. Once-through spent fuel, subjected to chemical separation, offers many potential options for managing its constituent parts:
i. Transmutation of radionuclide in fast-spectrum reactors;
ii. Recycling plutonium in existing light-water reactors or advanced thermal reactors;
iii. Stabilization of fission products in robust waste forms;
iv. Transmutation of long-lived fission products.
This concept leads to a closed fuel cycle “park” of four to five light water reactor generators, chemical separation and treatment of spent fuel rods, and a fast reactor for burning and transmutation of treated waste. The output from the park would be about 1% of spent fuel rod waste with heat loads and radioactive decay of the order of 3,000 to 4,000 years instead of large amounts of waste for storage and hundreds of thousands of years for heat load and radioactive decay peaks.

These reductions sharply reduce repository requirements, allowing expansion of nuclear energy generation sufficient to meet a significant percentage of world energy requirements. The closed fuel cycle of the parks diminishes proliferation concerns.

c. The third transformational technology is fusion power. As we speak, the six parties3 to the International Thermonuclear Experimental Reactor (ITER) are meeting at its future site in Cadarache, France, to draft the international agreement that will guide fusion energy research for the next two decades. Fusion energy uses deuterium from water, and lithium to create tritium, fusing deuterium and tritium into helium and a fast (14 MeV) neutron.4 Deuterium and lithium are abundant and cheap, the helium will escape from the earth’s gravity, and the energy of the neutron will generate electricity or produce hydrogen.

The fusion process is the same as that which powers our sun, and promises unlimited safe clean energy for the world. The Figure shows that a conservative estimate of about a third of today’s global energy usage can be generated with fusion power reactors by the end of this century, making a significant contribution to reduction of energy conflict.

d. The fourth transformational technology is biologically derived fuels. Two examples are: i. biofuels derived from plant cell walls (cellulosic ethanol), and ii. hydrogen produced from water using energy from the sun (biophotolytic hydrogen).

i. Cellulosic ethanol. The long term goal would integrate bioprocessing, now three steps (breakdown of raw biomass using heat and chemicals, use of enzymes to break down plant cell wall materials into simple sugars, and fermentation of the sugars into ethanol using microbes), into one. This requires the development of genetically modified, multidimensional microbes or a stable mixed culture of microbes capable of carrying out all biologically mediated transformation needed for complete conversion of biomass to ethanol. The necessary program of research would focus on three areas:
(1) Improved feed stocks. Increase biomass yield and characteristics; minimize crown and root systems; increase growth rate; and increase ratio of cellulose and hemicellulose to lignin.
(2) Improve pretreatment: optimize and exploit biological catalysts; reduce thermochemical treatments and resulting wastes; and raise yields of simple sugars for fermentation.
(3) Simplify conversion: eliminate the solid-liquid separation step; combine enzyme production, saccharification hydrolysis, and fermentation steps into one reactor.

ii. Biophotolytic hydrogen. Under certain conditions, green algae and cyanobacteria can use energy from the sun to split water and generate hydrogen. Research to understand and develop predictive models of hydrogenase (the enzyme that cleaves water to produce hydrogen) structure and function, genetic regulatory and biochemical networks, and eventually entire microbes, can lead to an “ideal” microbe to use in hydrogen bioreactors, or the “ideal” enzyme-catalyst to use in bio-inspired nanostructures for hydrogen production.

These four examples of transformational change and disruptive technologies, if successful, will reduce the gap between world energy demand and production, while at the same time stabilizing atmospheric CO2 at levels the earth can live with. The combination of conservation and clean reliable energy production can reduce the prospects of energy conflict, leading to a sustainable abundant energy future for our world.

References

1. “Basic Research Needs To Assure A Secure Energy Future”. U.S. Department of Energy, Office of Science, Basic Energy Sciences. Available from website: www.science.doe.gov. This report is based upon a Basic Energy Sciences Advisory Committee workshop that was held in October 2002 to assess the basic research needs for energy technologies to assure a reliable, economic, and environmentally sound energy supply for the future. The workshop discussions produced a total of 37 proposed research directions.

2. “Basic Research Needs for Solar Energy Utilization”. Available from website: www.science.doe.gov. This report is based on a BES Workshop on Solar Energy Utilization on April, 2005, to examine the challenges and opportunities for the development of solar energy as a competitive energy source and to identify the technical barriers to large-scale implementation of solar energy and the basic research directions showing promise to overcome them.

3. China, European Union, Japan, Russian Federation, South Korea, and the United States.

4. The fast neutron transmutes the abundant lithium-7 nucleus into helium and tritium, the source of tritium for fusion of deuterium and tritium in a commercial power plant.