One of the largest sources of carbon, CO2, is emitted as a pollutant and is attributing to the rising climate temperatures. So then why are we not using CO2 as a feedstock? Well, for one thing is it very very difficult. CO2 is incredibly stable as it is a thermodynamic sink. Therefore, It requires even more energy to convert it into something else, and where does all of energy come from? Fossil fuels. Thereby generating even more CO2 to convert CO2 into something useful. But if we can find a means for converting or reducing CO2 into a commodity through a less energy intensive pathway, then there is potential to generate revenue from “waste” and reduce emissions.
Currently, the US generates 5,500 million metric tons/yr of CO2. Industries are currently capturing and using CO2, approximately 200 million metric tons/yr in the food industry and oil and gas industry, but a majority of this is released back into the atmosphere. Only about 0.5% of the CO2 that is captured is sequestered and not released.
We can think about carbon/CO2 utilization in two categories, 1.) carbon sequestration (burying in deep geological formations) and 2.) carbon as a useful feedstock. I am focusing on the second categories because investigations into into using CO2 as a freely available and abundant feedstock to develop commercial chemicals, plastics, and building materials has the potential to be an economically viable industry. Additionally, carbon sequestration has its limitations, and although it is being heavily federally funded, it’s large scale deployment has estimates in the range of $30-70/ton attributed to the new CO2 transmission lines that will need to be built. There are instances where CO2 cannot be transported to sequestration sites.
One of my favorite examples being investigated for CO2 utilization to generate commercial chemicals is the oxidative coupling of CO2 with ethylene to generate acrylic acid with molybdenum catalysts. This is work done at Brown University in the lab of Dr. Bernskoetter.
Acrylic acid is used heavily as the raw material for polymers, coatings and adhesives. Global production of acrylic acid is 3.4 million metric tons/yr and with 60% by weight CO2, that is over 2 million metric tons/yr of CO2 that could be resold and prevented from entering the atmosphere. The production of acrylic acid through a more economically viable method would be advantageous, so much so that Dow has begun similar efforts to generate acrylic acid through the generation of 3-hydroxypropionic acid with the use of a biocatalyst. They claim that their process is 25% cheaper and 75% less greenhouse gas intensive.
The current process for acrylic acid production is the oxidation of propene and is incredibly energy intensive because it not only requires reaction temperatures of 200 – 300 C but also multiple distillations to remove impurities. Dr. Bernskoetter’s catalysts can oxidatively add CO2 and ethylene slightly above, if not close to, room temperature. However, at the moment, the biggest challenge is the reductive elimination of the hydroxide to release acrylic acid from the metal. But once that can be done, unlike the use of catalytic microbes, organometallic catalysts can more easily (and usually cheaply) be modified to improve upon turnover rates and efficiency. I am especially excited and looking forward to Dr. Bernskoetter’s next publication on this catalyst.
In talking to many people, very few were as excited about the President’s budget rollout as I was. This is probably due to the dim prospects of it actually getting passed this year it being an election year. Well, without going into a debate about whether or not it will fly in Congress, I do want to write a post about it as I think that it clearly showcases the importance that President Obama places on a clean energy economy. And because of this, I also think that congress should at least consider (at least the R&D side) the budget because if some of the clean energy investments are passed, the benefits will trickle down to their substituents and create more jobs and industries in their own states. The rest of the world is on board with investing in clean energy, why are we not? Although, according to Bloomberg, in 2011, we finally surpassed China in our investments in clean energy with 55.9 billion dollars when China invested 47.4 billion dollars in clean energy. Lets increase this!
I was excited to read that the Department of Energy’s proposed R&D budget for FY 2013 is 11.9 billion, an $884 million increase (8% of 2012 enacted). Within this budget request, specifically for R&D, there is (nearly a) 30% increase ($2.3 million) in the budget for Energy Efficiency and Renewable Energy (EERE) Programs, as well as (almost a) 30% increase ($350 million) in the budget for Advance Research Projects Agency in Energy (ARPA-e). I am proud of these increases because energy efficiency programs and efforts are some of the most important things that we can do now to reduce our emissions and save on energy. It it amazing how much economic sense improvements in efficiency can have and yet we consistently under invest in these types of efforts. But, there is a great piece by psychologist Brandon Hofmeister, that perhaps describes the cognitive barrier between knowing that something that makes economic sense and actually doing what makes economic sense. Nonetheless, more efforts to encourage consumers to be energy efficient and for utilities to reward their consumers when they are energy efficient is a very good thing.