NATIONAL HARBOR, Md.--The ARPA-E Summit, held earlier this week, is called an "energy innovation summit" to highlight some of the clean-energy technologies funded by the Advanced Research Projects Agency-Energy (ARPA-E). At the conference, several awardees and finalists for grants showed off research in many areas, including energy storage, solar, converting carbon dioxide into fuels, and wind power.
Seen here is prototype of an electrolyzer from Sun Catalytix which splits hydrogen from water. The company is already developing a relatively inexpensive catalyst for a traditional electrolyzer. An ARPA-E grant funded longer-term work to generate hydrogen gas--the bubbles floating up from the square--from a photovoltaic cell in water using its catalyst.
What's the best battery chemistry after lithium ion batteries? PolyPlus Battery is working on lithium air and lithium seawater batteries which could extend electric vehicles' driving range to 500 miles. In a demonstration, PolyPlus puts a battery in water to generate a current. If it proves out as hoped, it says the energy density of its technology will rival liquid hydrocarbons.
Advanced biotechnology and genetic engineering offers one of the paths to making biofuels. At the ARPA-E Summit there were a number of university research efforts around "electrofuels," or fuels made directly from micro-organisms that consume carbon dioxide and energy to create a fuel. The idea is that these electrofuels can work more efficiently than the photosythetic route of growing plants and then extracting fuel from the biomass.
This display was from the University of Massachusetts which is working with microorganisms that feed on electricity and carbon dioxide to make organic compounds. Those compounds could then be converted into liquid fuels or other products.
Another demonstration of electrofuels work was from Harvard University where researchers are genetically engineering e.coli bacteria to perform different functions en route to making a fuel. Here researcher Wade Hicks holds a model of a peptide, a type of molecule that the bacteria could make to carry electrons. With electrons and sunlight, the bacteria could take in carbon dioxide and make an organic molecule. The organic molecule could then be converted into a fuel.
Planar Energy from Florida is designing a solid-state battery made by essentially spraying materials onto a metal substrate. These large-format cells would allow for cheap production and small batteries which could be used for electronics or vehicles. This image shows the coating of a self-assembled anode (the bumpy layer on right) on the metal substrate (left).
Energy storage is a big focus of research at ARPA-E. Here is MIT professor Donald Sadoway showing a model of a liquid metal battery his group intends to make. The idea is to assemble a battery with two liquid metals which don't mix (like oil and water don't mix) and a molten salt electrolyte. Because the three materials are of different density, they will form three layers. The design promises simplicity and long life and very high energy density. A spinoff company, called Liquid Metal Battery, hopes to have utilities use it to store hours of solar and wind power, which is considered by many the holy grail of energy storage.
Here's another company pursuing materials science breakthroughs--Phononic Devices. The company is making thermoelectric modules, which it says will be more efficient than current materials (bismuth telluride is often used). The company intends to design the chips as a replacement to copper heat sinks for data center computers, refrigeration, and later using waste heat to generate electricity.
Waste heat is MTPV's friend. The company is developing chips which can convert infrared energy into electricity. Its manufacturing process is an improvement over existing technologies, making the chips more efficient, according to the company. One of its investors is French buildings giant Saint Gobain where these heat generators are being beta-tested in glass factories. Over time, MPTV wants to design chips that can work with lower temperatures. The photovoltaic chips would fit over the four squares seen here. Water flows through the two tubes under the copper heat sinks to remove the heat.
Makani Power is making an airborne wind turbine, which would be able to operate in higher altitudes and capture more wind energy. This pylon attaches to a wing that spins in a large circle while tethered to a platform. It takes essentially the same circular path of a tip of a wind turbine's blade but, because it's lighter and operates higher, it can deliver cheaper electricity, according to the company.
Altaeros showed off its concept--an inflatable wind turbine that would supply power to remote, off-grid areas. The idea is to build a helium-filled balloon around a traditional 100-kilowatt wind mill to capture higher wind.
Wave power company Oscilla Power is working on a wave power buoy that operates using a special material that will eliminate moving parts from the inner cylinder. The idea is to use magnetostrictive materials which, when stretched by the motion of waves, will create magnetic energy, which can be converted into electrical energy.
General Motors received a grant to pursue development of a technology that creates mechanical energy from a difference in temperature. It could be used to use the waste heat of cars into useful energy, the same way that people envision using thermoelectric chips, which convert heat to electricity. A spring made out of shape memory alloy would stretch or contract based on changes in heat. This machine shows a spring coil, fitted around the wheels, turning the wheels based on a flow of heat coming from the bottom of the enclosure.
Shown here is a model of a solar concentrator from Alternative Designs, part of a complex system to store several hours of solar energy. The company intends to build a concentrator similar to this which would be equipped with a Stirling engine, a type of piston engine which runs on heat. The engine would be fitted on the tip of the rod, collecting heat made by concentrating light.