Environment-Enhancing Energy (E²-Energy) technology is to produce hydrocarbon fuels and chemicals from biowaste (including those from animal, human and bioprocessing) and algae, and at the same time capture carbon, reuse nutrients and clean wastewater. Petroleum was formed from biomass buried underneath the ground and subjected to thermochemical conversion processes over geological time. Mimicking this natural process, we are focusing on technologies of hydrothermal liquefaction of biomass into crude oil and algal production using recycled nutrients in wastewater. A road map of the E²-Energy is shown in the following figure: First, volatile organic solids in biowaste is separated and converted into biocrude oil via hydrothermal liquefaction (HTL); Second, algae is grown in the resulting wastewaters to remove excess nutrients and capture carbon dioxide; Finally, the algae is fed back to the HTL reactor, as a sole feedstock or as an additive, to be converted into additional biocrude oil. This synergistic process is extremely advantageous because it brings two rivals - "Energy Production" and "Environment Protection" - together to complement rather than compete. It simultaneously improves water quality, captures carbon dioxide and increases biofuel yield.

This team has successfully developed a HTL technology that converts 70% of volatile solids in swine manure (dry mass basis) into biocrude oil with heating values between 32-38 MJ/kg, which is 75-90% of petroleum crude heating value. The energy recovery ratio - defined as the energy output of the HTL biocrude compared to the process energy input (E_out:E_in) - is 3:1 at laboratory scale, and 11:1 when heat exchangers are included in a pilot-scale HTL reactor. We have also performed HTL conversion of algae and cyanobacteria to biocrude oil without any catalysts. Our experiments have shown that both high-lipid algae (genera Chlamydomonas), and lower-lipid algae (genera Chlorella, Spirulina) can be converted efficiently (>40% of dry mass) into biocrude oil. This approach, converting low-lipid content algae into biocrude, can effectively break thorough the three bottle necks in the existing extracting-bio-oil-from-algal paradigm: high-lipid but slow growing, low resistance to contamination, and usually requiring drying.