This paper introduces a new technique called species conservation for evolving paral-lel subpopulations. The technique is based on the concept of dividing the population into several species according to their similarity. Each of these species is built around a dominating individual called the species seed. Species seeds found in the current gen-eration are saved (conserved) by moving them into the next generation. Our technique has proved to be very effective in finding multiple solutions of multimodal optimiza-tion problems. We demonstrate this by applying it to a set of test problems, including some problems known to be deceptive to genetic algorithms.

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As required by the U.S. Department of Energy contract with the Independent Review Panel, these are the panel's unanimous technical conclusions, arrived at from data collection, document reviews, interviews with industry experts, and panel deliberations from November 2012 through March 2014. All reported compression, storage, and dispensing (CSD) contributions to the cost of hydrogen dispensed at the forecourt include a real 10% internal rate of return on investments and are expressed in 2007 reference-year dollars (2007$). For the central production pipeline scenario, the hydrogen is delivered to the refueling station via pipeline providing an average annual rate of production of 1,000 kg/d. For distributed generation, the hydrogen is produced by steam reforming of natural gas at the forecourt refueling station at a design capacity of 1,330 kg/d annual average rate of production. For the tube-trailer scenario, the hydrogen is delivered as compressed gas at 500 bar via overland tractor trailer to a forecourt refueling station with a design capacity of 850 kg/d annual average rate of delivery. The central production pipeline and forecourt stations sizes (1,000 kg/d and 1,330 kg/d, respectively) were chosen for this analysis because they reflect the station sizes modeled in the U.S. Department of Energy's publicly available cost-evaluation tools: the H2A Forecourt Hydrogen Production Model (H2A) and the Hydrogen Delivery Scenario Analysis Model (HDSAM). The high-pressure tube-trailer station size (850 kg/d) evaluated was the result of the Independent Review Panel's cost-optimization analysis. The Independent Review Panel found that for a high-pressure tube-trailer delivery scenario, an 850-kg/d dispensing station resulted in the lowest cost of dispensed hydrogen based on the delivery technologies most likely to be available and thus represented the best approach toward achieving the U.S. Department of Energy's 2020 dispensed hydrogen cost target for centrally produced hydrogen. The costs reviewed in this report include only those costs contributing to the selling price of hydrogen by the forecourt CSD portion of the hydrogen station and do not include the costs of production or delivery to the station. Conclusions• The current cost of CSD at the forecourt, projected in 2007$ for a mature market (15% penetration of fuel cell vehicles) ranges from $2.00/kg of hydrogen to $2.80/kg of hydrogen for the central production case with delivery via pipeline with a base case 1 of ~$2.40/kg of hydrogen. The wide variance is a result of uncertainties in the cost and 1 The base case, defined in the Panel Results section of this report, is the cost/value that the Independent Review Panel determined is most likely. iv efficiency of the compressor, the cycle life of the vessels used in the high-pressure cascade system, and the station installation costs. These costs were evaluated using the Current Hydrogen Delivery Scenario Analysis Model Version 2.3 (released October 2011).

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