Date: Sep 12, 2011 Source: (
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What's old is new again as Terrajoule revives an old steam engine technology—stoked with solar power to drive farm and industrial power.
Eric Wesoff
September 12, 2011
Farmers in California's Central Valley grow the food that feeds this country by pumping enormous amounts of water from wells into the topsoil.
Those well pumps are powered by electricity. And in many cases that electricity comes from diesel gen-sets that run on, you guessed it, diesel. That diesel is polluting and comes with an expensive -- and volatile -- price. Diesel from truck and generators is responsible for a significant portion of the particulate pollution in the Central Valley.
And crucial to farmers, pumping water and paying for the diesel is an enormous part of the cost to run a farm.
Terrajoule, a five-employee, distributed energy generation startup in Redwood City, California is targeting this market as its first customer pool. There are 10,000 diesel irrigation pumps in California -- it's a niche, but a large niche. There are over 300,000 electric pumps and 50,000 diesel pumps in the Western U.S. The firm's energy system will work in other industrial energy applications, as well.
I met with Steve Bisset, CEO, David Henkel-Wallace, VP of Engineering, and Franklin, a mammoth-sized Irish wolfhound, in the firm's first conversation with the press.
Instead of a tank of diesel and a diesel generator, the firm employs a concentrated solar power (CSP) trough plant to generate super-heated water at 100 psi, which is stored in a 30,000-gallon tank. The steam from the tank drives an efficient steam engine, which turns a shaft and spins a generator. The farmer gets distributed, dispatchable renewable energy with no diesel and no pollution.
The very steam-punk steam engine is a resurrection of a vintage World War II design called the Skinner Universal Unaflow. The positive displacement engine was used in Navy ships, some of which were still running up to a few years ago. Bisset described it as "a very-well refined thread of steam engine technology" that has "little change in efficiency despite changes in output power." It's a viscerally impressive sight to see the system in action, one that's evocative of an earlier industrial age.
The re-invention of this old steam engine design is the brainchild of Robert Mierisch, Terrajoule's Chief Engineer and the former Research Director of Thermal Systems at Ausra. (Ausra is now part of Areva. Other Ausra alumni have formed renewable firms Agile Energy and Chromasun.)
Bisset, the CEO, sees the target customers -- factories and farms -- as "rational customers who understand the difference between capex and opex" and who will buy products based on realistic payback times. He adds that, "Straight solar power doesn't address the farmer's energy problem -- they want power when they want it."
Terrajoule's systems have a modular unit size of a 300 kilowatt peak/100 kilowatt flat output over the day. Customers need to use the system 1,000 to 2,000 hours per year and consume more than one megawatt-hours in order for the Terrajoule system to be economical. Most Western United States agriculture users fit this profile, according to Bisset. Most factories fit this profile, as well.
Because the system is CSP, it still needs a relatively high DNI, and "California's Central Valley is more than adequate," according to Henkel-Wallace, the VP of Engineering.
Henkel-Wallace provided some numbers on cost and efficiency:
Storage has a capital cost of $60 per kilowatt-hour of storage capacity, the typical configuration provides 12 hours of storage.
The firm foresees the levelized cost of energy (LCOE) as under 10 cents without government assistance with a five-year payback.
CSP troughs have an efficiency of approximately 70 percent and the steam cycle efficiency is above 30 percent for an overall system efficiency of 22 percent.
The entire system is made in the U.S.
The firm uses JKB Energy as their sales channel partner, EPC, and developer. According to Bisset, "They've sold to farmers in the valley for 30 years."
The small firm is working on its first full-scale system and still has to sell, install, and prove out the economics and reliability of this old-is-new invention.
Still, Terrajoule proves how far entrepreneurs can go -- fueled by a little cash, Australian engineering, and testosterone. Arno Penzias and Forrest Baskett of NEA are on Terrajoule's board and the startup is now on the hunt for a $7 million round A.
