Tapping into Nature: Guiding light for energy storage
This is an excerpt from the Tapping into Nature report by Terrapin Bright Green.
Energy conversion allows us to leverage energy sources for useful work. Whether it is converting stored chemical energy (fossil fuels) to thermal energy or transforming photons (sunlight) to electrical energy, the energy industry hinges on the efficient storage and conversion of energy.
In nature, entire ecosystems are structured around variable and limited energy sources, forcing organisms to optimize energy conversion and storage to ensure their survival. Consequently, nature has evolved many energy strategies barely explored by today’s businesses.
Ecosystems are driven by readily available, distributed and renewable energy sources. Individual organisms make use of solar, chemical, wind and gravitational potential energy — all uncentralized sources — to move, sense, migrate and otherwise accomplish tasks. Maple tree seeds disperse using the wind; plant roots orient using gravity, which guides root tips downward; living things use the energy flows that surround them. Many businesses have adopted similar strategies, relying on distributed renewable energy sources to power their operations, thus reducing long-term costs. Products inspired by the use of readily available energy flows include BioPower Systems’ wave- and tide-powered electric generators.
Organisms rely on transient, distributed energy sources, which force them to store captured energy in the form of long-lasting chemical fuel. Unlike our current electrical grid that produces energy for immediate consumption, organisms capture energy, store it in chemical bonds and expend these fuels as needed. As we transition to using transient, renewable energy sources, our energy infrastructure will require a similar storage strategy. In development today, solar fuels produced from artificial photosynthesis could be integrated into our current infrastructure and boast the same beneficial properties of biological fuels.
Most of our cars, engines and power plants run on a narrow range of fossil fuels. In contrast, animals metabolize a variety of fuel sources such as fats, proteins and carbohydrates. Some microbes consume an even greater range of "fuels," metabolizing cellulose, iron, sulfur compounds and ammonia. Using the mechanisms of microbes, researchers are attempting to modify engines and other power generation devices to consume a greater variety of readily available, renewable fuels. One example is the Pilus Cell, which harnesses the metabolic activities of specialized bacteria to break down organic compounds in wastewater, producing electricity, valuable chemicals and clean water.
Ocean waves carry a large amount of energy, but this resource remains largely untapped due to the power delivery and lifespan challenges facing the current generation of wave energy capture devices. BioPower Systems, an Australia-based renewable energy technology company, addressed these issues by observing how aquatic plants and algae sway in ocean swells without suffering much damage.
They developed the bioWAVE system, which features a unique "frond" structure consisting of three air-filled paddles fixed to a submerged lever that pivots back and forth with the waves, generating electrical power. The self-regulated O-Drive, a hydraulic power converter in the base, delivers consistent power despite fluctuations in wave intensity. When wave intensity is too high, the paddles automatically fill with fluid, sinking the structure into its "safe" position on the seafloor. A $15 million demonstration project is underway in Port Fairy, Australia, to test the 250kW bioWAVE, paving the way for future 1MW commercial installations and wave energy farms.
Researchers at University of Leeds and Cornell University have developed the μMist Platform Technology, a spray system inspired by the defense mechanism of bombardier beetles. Using a unique valve system, the 2 cm/0.78 inch-long beetles are capable of spraying pulses of boiling liquid distances of up to 10 times the length of their bodies. The team studied the valve to develop μMist, which can spray small vapor droplets using lower injection pressures than other systems.
The capability to reliably deliver uniformly small droplets of fuel allows internal combustion engines to convert chemical energy to thermal energy more efficiently, resulting in a more efficient combustion cycle and decreased GHG emissions. Swedish Biomimetics 3000, the sole licensee of μMist, has collaborated with Lotus and Cosworth, both U.K.-based automobile companies, to develop new fuel injection systems. The technology also has applications in personal care, drug delivery and fire protection.
Products in development
The "waste" in wastewater from manufacturing, food processing and sanitation contains about 10 times more energy than the amount used to treat it, and wastewater treatment is an energy-intensive process.The Pilus Cell, a microbial fuel cell in development by the Ohio-based synthetic biology company Pilus Energy, generates electricity, clean water and valuable chemical products from wastewater.
Pilus Energy’s technology uses genetically modified bacteria to break down the organic molecules in wastewater, generating molecules such as methane and isoprene. The Pilus Cell has been approved for pilot testing at the EPA Test & Evaluation Facility to demonstrate its potential use in industrial sewage treatment plants. Pilus Energy was recently acquired by Tauriga Sciences, a diversified life sciences company.