Proton Ventures and Delft University of Technology (TU Delft), both of the Netherlands, announced in early February the formation of a new company, Battolyser B.V. The company’s initial goal is to build and demonstrate a pilot version of the eponymous technology that stores electricity and produces hydrogen. Hans Vrijenhoef, who will direct the new company, indicated that a fully realized system would include an ammonia production train so that the hydrogen could be stored and transported at low cost. Vrijenhoef is already the Director of Proton Ventures B.V., a member of the NH3 Fuel Association’s Global Federation Advisory Board, and the originator of the NH3 Event power-to-ammonia conference.
The battolyser first came to light in a paper published by Fokko Mulder, Professor of Materials for Energy Conversion & Storage at TU Delft, and four co-authors in Energy & Environmental Science in December 2016. At the heart of the system is a nickel-iron battery. By definition the battery functions as an electricity storage device. The twist is that when the battery is fully charged, any additional electricity that comes in electrolyzes the water present in the cell to produce hydrogen. A more detailed discussion of the technology can be found in a contemporaneous Ammonia Energy post. Still more detail can be found in Mulder’s Energy & Environmental Science paper, Efficient electricity storage with a battolyser, an integrated Ni–Fe battery and electrolyser.
The new company has not shared details on its path to full validation of the technology, but John Nijenhuis, TU Delft’s Technology Transfer Officer, said in a December 20, 2016 press release that “the battolyser needs to be scaled up to the size of a shipping container to prove that the technology is also suitable at the scale of the power produced by a large wind turbine.” He indicated that “the aim is to have the large battolyser ready and tested within eighteen months.”
The battolyser’s energy storage and hydrogen-producing capabilities place it in a category of dual-use assets. The economics of such assets can be attractive when the two uses produce distinct revenue streams. Whereas hydrogen and/or ammonia can clearly be sold into industrial, agricultural, and/or energy markets, the battolyser’s energy storage face could produce the more important mid-term cash flow. According to a Navigant Research report, large-scale battery-based energy storage systems (ESS) are “emerging as one of the attractive new sources of the ancillary services required to maintain stable and efficient grid operation.” Navigant projects that 8.6 GW of new ESS capacity will be deployed in Western Europe through 2026 in conjunction with the increasing proportion of renewable electricity generation. This translates to an order-of-magnitude capital cost of $30 billion.
The economics of dual-use assets will be superior to those dedicated to a single use only if neither use is deeply suboptimzed by the combination. Certain of the battolyser’s basic characteristics point to a favorable prognosis in this regard. According to Mulder’s Energy & Environmental Science paper, the battolyser’s chemistry permits a relatively low cost per unit of energy stored; its overall energy conversion efficiency is rated at “up to 90%;” and its robust durability under stressful charge and discharge conditions will produce a long useful life.
The most vivid depiction so far of the battolyser’s potential comes from “Power to Ammonia,” a study released in March 2017 by a team under the leadership of Dutch research agency ISPT. (A detailed description of the study was provided in an April 2017 Ammonia Energy post.) The study’s main conclusion is that “CO2 neutral NH3 produced in an electrochemical way from sustainable electricity will be a feasible alternative for NH3 produced from natural gas in the longer term.”
The heart of the study is a benchmarking exercise “to compare state of the art NH3 production from SMR [natural-gas-based steam methane reforming] combined with Haber Bosch NH3 synthesis on the one hand with electrochemical production technologies using electrochemical H2 production with Haber Bosch synthesis or direct electrochemical NH3 synthesis on the other hand.”
The study evaluated the battolyser and four other alternative methods of ammonia synthesis: solid oxide electrolytic cell (SOEC), low-temperature solid state ammonia synthesis (SSAS), proton exchange membrane, and high temperature SSAS. The battolyser ranked third in energy conversion efficiency. When overall economics were considered, however, the battolyser was seen as one of the two most promising technologies. By the year 2030, according to the report, “only SOEC and battolyser are able to achieve lower costs than the SMR in the high renewable energy scenario. These can be explained by the high efficiency of SOEC and the additional revenues generated by the battolyser by acting also as a battery.”
Mulder commented in the Proton Ventures press release that he envisions the battolyser in use “on a global scale in many GW / GWh plants where green power generation capacity is realized of such a size.” Vrijenhoef said that “great interest has already been shown in this new technology” from multiple multinational corporations.