25-08-2017, 09:32 PM
Wind Energy and Production of Hydrogen and Electricity — Opportunities for Renewable Hydrogen
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Executive Summary
Hydrogen can be produced from a variety of domestic, renewable sources of energy. An
assessment of options for wind/hydrogen/electricity systems at both central and distributed scales
provides insight into opportunities for renewable hydrogen as well as research priorities for this
hydrogen production pathway.
The analysis of the central production of hydrogen from wind was conducted. This technology
involves hydrogen production at the wind site with hydrogen delivered to the point of use. The
results of this study are that hydrogen can be produced at the wind site for prices ranging from
$5.55/kg in the near term to $2.27/kg in the long term. A research opportunity in this scenario is
the elimination of redundant controls and power electronics in a combined turbine/electrolysis
system.
A second analysis was completed in which wind power was used in a distributed fashion for
hydrogen production. The wind farm provides a signal to a remotely located electrolyzer, which
allows the electrolyzer to run only when the wind is blowing. An advantage of this scenario is
that signals from many different wind farms could be used, which would increase the capacity
factor and thus decrease the cost of the hydrogen production system. The results of this second
study are that hydrogen can be produced at the point of use for prices ranging from $4.03/kg in
the near term to $2.33/kg in the long term. This novel approach results in low production costs
and could minimize delivery costs if the electrolyzer was located at the filling station.
HOMER Model
For this study the HOMER® model (hereinafter “Model”) was used for the system optimization
and hydrogen price calculation. The Model was developed at NREL to allow users to optimize
electric systems and ease the evaluation of the many possible configurations that exist with such
systems.1 For example, when designing an electric system to meet a 30 kW load for an hour
every day, the Model can answer questions such as: should the system have enough turbines so
that hour always has 30 kW, or should battery storage be added, or a diesel engine, and which
option costs less? The ability to model hydrogen was added to the Model in 2004, and further
enhanced in 2005 for use in this study.
One of the advantages of using the HOMER® model is its ability to conduct analysis on an
hourly basis. For this study, system components, available energy resources, and loads are
modeled hour by hour for a single year. Energy flows and costs are constant over a given hour.
This type of model is ideal for showing intermittent renewable electricity producing hydrogen
for fluctuating hydrogen demands.
The Model requires inputs such as technology options, component costs, and resource
availability. The Model uses these inputs to simulate different system configurations, and
generates a list of feasible configurations sorted by net present cost (NPC). NPC can also be
referred to as lifecycle cost and is the present cost of installing and operating the system over the
lifetime of the project. Model results include a COE (cost of energy) or COH (cost of hydrogen)
for each feasible configuration. 2 The configuration with the lowest COE or COH is determined
to be the most economic solution.
Results
The purpose of this study was to determine if hydrogen can be produced economically from wind generated electricity. The Department of Energy Hydrogen, Fuel Cells and Infrastructure Technologies (DOE HFC&IT) program goal for delivered hydrogen in 2015 at the filling station is $2-3/kg,6 and the program goal for delivery and dispensing is $1/kg for delivery.7 This means that for Case 1, hydrogen needs to be produced for $1-$2/kg as the delivery cost is not included in this study. For Case 2, the hydrogen can be produced for roughly $2-3/kg, as the hydrogen can be produced at the point of use, eliminating the need for delivery.