Frequently Asked Questions
Green Carbon – What is it?
Green Carbon describes fuel sources that use carbon-based energy resources in an economically, environmentally and socially sustainable fashion. It recognizes that the true challenges with conventional and unconventional hydrocarbons are not in the fuels themselves, but in their collection, distribution, and use (e.g. combustion). It also looks just beyond petroleum and anticipates the emergence of carbon-based biological fuel sources. The pursuit of green carbon enables society to transition gradually away from fossil fuel combustion while using these resources for hydrogen generation in the near term, increasing use in the development of materials that fix the carbon and capitalization on carbon dioxide generated by turning it into a useful commodity.
Green Carbon technologies are not necessarily "carbon neutral" or "zero carbon”, but rather they reduce the carbon load in the aggregate. Green Carbon is an adaptive response to a moving target as we continue to improve our understanding of anthropogenic climate change and learn how long our fossil fuels will last at affordable prices. Green Carbon should adopt as it is prime directive the two words: "Be Prepared", where energy, sustainable fuel supply, and environmental impact are concerned.
What is the Green Carbon Center?
The Green Carbon Center is a research initiative at Rice University which develops the scholarship and technological innovations required to extract ever-increasing amounts of energy and value from carbon atoms while minimizing the deleterious impact of these technologies. We calculate this benefit not locally, but over the whole of Planet Earth.
Rice University is well-positioned to take on this challenge; indeed, our strong research core, history of multidisciplinary problem-solving, and our location in the energy capital of the world make us the ideal university for the task. Physical, chemical, biological, and catalytic processes can be brought to bear to get "more bang for the buck" from carbon-based fuels, and new materials and processes are developed to ensure continually diminishing environmental impacts. Central also to our activity is the education of the next generation of scientists and engineers. We envision scholars who are able to think holistically about the challenges of innovation given the natural constraints placed on energy resource development by societies, nations and the planet.
What are some examples of green carbon technologies?
Carbon sequestration and capture are often the immediate topics associated with managing the environmental impact of fossil fuel combustion. Many green carbon technologies are aligned with these existing areas, but include a more holistic view of the process that recognizes the need to do more than just control the carbon footprint. Commercialization proceeds in accordance with the most economically viable initiatives. For example, it is possible to create carbon sequestration methods driven by their economic value. Deep sequestration of carbon dioxide underground as a waste material is expensive and undesirable given its long-term storage and concerns with its possible hazards. Another example is the use of carbon dioxide as a refrigerant where it has positive economic value. In this context, it can replace a hydrofluorocarbon (HFC) that has 1000x greater global warming potential (GWP). Translated into other terms, it would take 1000 carbon dioxide refrigerators to equal the GWP of one HFC refrigerator, assuming equal loss rates. Likewise, carbon dioxide can be recycled as feedstock for carbonates and the food and beverage industries, and more abundantly used for enhanced oil recovery rather than using another dwindling resource: water. In all these cases, captured carbon dioxide can go to market with positive economic value rather than being sent up the smokestack as gaseous waste. And if, for example, the adverse consequences of atmospheric carbon dioxide emissions proves to align with the lowest warming models, these efforts are not wasted, as substantial positive economic value has been obtained, and the "stretching" of energy supply from carbon is still beneficial.
The production and availability of hydrogen is a central element in many green carbon examples. Hydrogen may be made in an inexhaustible supply from sunlight and water as technology improves to render this process economical. What other elemental primary fuel (not derived from any other fuel) will be available as long as the sun shines and the wind blows? There are a variety of ways, such as algae, photoelectochemical, photocatalytic, and catalytic solar thermal water cracking, not to mention nuclear-thermal cracking from plutonium-powered reactors. With ample hydrogen, it is possible to desulfur and hydrogenate sour crude, so one will be putting a bit of sunshine in every tank of gas. Hydrogen is also the ideal fuel source for cost-effective fuel cells, without platinum, that generates electricity efficiently. Further down the road, captured carbon dioxide is combined with renewable hydrogen (from sunlight-based water splitting, for example) to create renewable synthetic carbon-based liquid fuels or chemical feedstocks.
Green carbon fuels can also come from biological sources. Liquid fuel can be formed from cellulose by using hydrogen for the hydrogenation of cellulose, displacing the OH as water; this substance would have higher energy content per carbon atom than the original biofuel. This green carbon becomes even greener if it is used to produce biochar that sequesters carbon and can be used to improve soil capacity. Microbial systems can also be instrumental in managing and transforming diverse forms of carbon into useful fuel sources.
Finally, the vision of green carbon certainly encompasses a whole range of new capabilities for energy storage and generation. A better nanoengineered battery electrode, for example, would provide higher amounts of charge and more cycles before failure. It would also extract greater utility from fossil fuels that were consumed in making the battery and would allow longer intervals before recycling. Similarly, advances in catalyst development can enable highly efficient fuel cells to operate at lower temperatures from simple fuel stocks.