Michael Idelchik is vice president of advanced technologies at GE Research, one of the world’s largest corporate research organizations. He oversees a wide range of projects, including ones aimed at improving conventional energy sources–with better coal and gas turbines, for example–as well as projects involving renewable energy, primarily wind turbines. At the EmTech@MIT 2009 conference, Technology Review spoke to Idelchik about some of GE’s most daring long-term research efforts.
Technology Review: What is the riskiest, most early-stage research going on at GE Research?
Michael Idelchik: We’re an industrial research lab, so early-stage is relative. But we have a number of projects that take years to develop. I’ll give you a couple. Pulse detonation technology, or supersonic combustion. With this one, rather than burning fuel at constant pressure, you let the pressure rise, so basically you generate a shock wave; you’re releasing heat in a detonation. An existing turbine burns at constant pressure. With detonation, pressure is rising, and the total energy available for the turbine increases. We see the potential of 30 percent fuel-efficiency improvement. Of course realization, including all the hardware around this process, would reduce this.
TR: In reality, the efficiency improvement in a power plant would be lower than 30 percent. How much would the improvement actually be?
MI: I think it will be anywhere from 5 percent to 10 percent. That’s percentage points–say from 59 to 60 percent efficient to 65 percent efficient. We have other technology that will get us close [to that] but no other technology that can get so much at once. It’s very revolutionary technology.
TR: How will this technology be used?
MI: The first application will definitely be land-based–it will be power generation at a natural-gas power plant.
TR: You will be detonating the fuel over and over again, something like an internal combustion engine?
MI: Basically you detonate anywhere from 50 to 80 hertz. Then you have unsteady flow going into the turbine. So you need to rethink how your turbine works. You don’t have a steady flow anymore.
TR: What are some of the challenges, in terms of materials or that sort of thing, to making that work?
MI: You have to look at the mechanical stability, vibrational analysis. You have to protect the compressor; detonation happens in both directions, so you have to close one end. So controls and synchronization of the detonation chambers become a really big challenge as well. You have to absorb the energy from detonation and convert it to shaft horsepower. That has to be done very well, otherwise you can lose everything in the turbine. What blade design and nozzle design will allow you to extract the most horsepower?
TR: What advances in materials or computation make this thinkable now?
MI: The ability to do multiscale models and simulations–you have from nanoseconds all the way up to 20 to 30 milliseconds. Evolution of valve technology and materials to go with that. Understanding how to design a robust detonation tube, how to produce detonation consistently and operate within the load range of the turbine, from idle to max power.
TR: Do you think it will be possible someday to apply this to aviation? Jet engines?
TR: What are the challenges?
MI: Weight. It will take a while. To stay in this business long-term, we have to take big bets. And that’s a big bet.
TR: This will make existing power plants more efficient, and so reduce carbon emissions. What about renewable energy?
MI: We’re going offshore, making large offshore wind turbines. Today offshore wind is much more expensive [than onshore wind] because the platform for the turbine is so expensive–basically you have to build an oil platform. [To bring down costs] you have to put together technologies that allow you to extract the most from wind.
TR: I’ve been told by some experts that wind turbines can’t be made much more efficient than they are now. Can you make them much more efficient?
MI: Yes, you can. If you look at a wind turbine, there are a couple of things. One is the blade. The blade has to get larger. It has to be much more aerodynamic. It has to be able to take twist-bend coupling. It has to look more like a wing, although it’s actually more complex than a wing, because your velocities vary from the hub to the tip. We believe there are a lot of opportunities in the next-generation wind blade. We are developing low-cost composites to be able to build a spar–the core of the blade–that handles the loads. And then we believe that the next generation of wind blades will have active flow control, to be able to shape the airfoil for the conditions, to get maximum power out of it.
TR: As in shapeshifting materials?
MI: There are many ways to get active flow control. One way is just to blow air from the leading and the trailing edge. We just need to find a way that will get us there at the lowest cost and the highest reliability, that can withstand lightning strikes and all the environmental considerations.
TR: So that’s the blades. What else could you do?
MI: The generator. Today you go through the gearbox, to the generator, into the inverter to get to the right voltage, the right frequency. We believe in going to direct drive [without a gearbox]. That can lead to very big generators, 8 meters in diameter. We are working on changing the paradigm, making these generators smaller, to be able to handle low speed with a high efficiency. We are also developing better power electronics to produce higher voltage for transmitting the power to shore. We are working with a number of technologies to make the wind turbine out in the sea economical.