Terrajoule has closed an $11.5 million round of funding from several investors, including Air Liquide, a French multinational corporation and a world leader in the industrial gases business. NEA and two individual investors are also on board to help the Redwood City, CA solar and waste-heat energy storage start-up.
Terrajoule’s technology employs a steam engine design that has been used in American Navy ships. Using a steam engine might seem anachronistic, but parabolic solar troughs are utilized for generating the steam, which drives the engine in order spin a shaft to make a generator produce electricity.
The storage part of this energy production equation is a 30,000-gallon tank of hot water that is pressurized. This water can be turned rapidly into steam, which re-starts the electricity production when there is demand. No diesel fuel is used to run any part of their process
so there is no air pollution, and reciprocating steam engines have been described as much more efficient than steam turbines.
The California start-up was created to make solar power available at any time,
“Terrajoule was founded in 2009 to resolve the fundamental barrier to the widespread adoption of solar power as the most practical and economic source of new electricity generation for the 21st century. That barrier is intermittency, and the solution is to build energy storage into the systems that convert solar energy into electric power.” (Source: Terrajoule)
They say their approach to storing energy costs less than 20% of any form of battery storage.
Distributed power is what they envision for the future, so their systems range from 100 kW to 10 MW, with some larger ones as well. Modest investments for customers and and wide scalability are keys to their business model.
They say avoided expenses such as diesel fuel and electricity will result in a capital payback time of 2 to 5 years, and system life has been pegged at 25 years minimum. Their systems have zero emissions and are made of non-toxic materials.
The use of parabolic troughs combined with a steam engine and energy storage has been done before. In 1981 Australia’s White Cliffs Solar Power Station used 14 troughs and one steam engine.
Image Credit: Terrajoule