Energy Storage Projects - DNV Kema

Energy
Storage

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Contents
n Energy Storage
Selecting best-fit energy storage technologies 3
Battery energy storage system for wind energy 5
Power to Gas: methanation of hydrogen 7
Zinc-Air flow batteries for power distribution networks 9
Test facilities for energy storage systems 11
Grid reliability and operability using flexible storage 13
Modular electricity storage system 15

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Selecting best-fit energy
storage technologies
Energy Storage Select
Many clients have come to DNV KEMA seeking a way to assess and choose the energy
storage technology that best performs a specific application or set of applications at the
best return on investment. Identifying the best storage technology for an application
requires careful analysis of many interrelated factors. Few standards or test procedures are
available to govern and help compare these devices. As such, many uncertainties surround
these business and technical factors, which impact investment decisions.
Energy storage technologies can vary widely from an electric battery to a flywheel to thermal
units. As a result, operational characteristics, including deliverable power, efficiency,
discharge time, and cycle life, differ across technologies. Business factors such as installed
cost, the number of applications the device can be applied to, and the ability to monetize the
intended benefits of the application, also add to the challenge of identifying a technology’s
cost-benefit ratio and developing the business case for investment.

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Project
DNV KEMA developed Energy Storage Select (ES-Select) as a sophisticated,
decision-support tool for end users and developers. Launched in June 2011, ES-Select
provides targeted, end-user defined analyses to help determine the return on investment of
energy storage technologies for the desired application.
ES-Select performs several core functions:
n Maps available and emerging technologies, from compressed air energy storage to
nickel-cadmium batteries and thermal storage
n Allows a user to choose a storage technology for multiple simultaneous applications, like
T&D upgrade deferral and area regulation, and considers the compatibility of
simultaneous applications in assessing the combined value
n Handles uncertainties in application value, storage cost, cycle life, efficiency, discharge
duration, and other parameters
n Uses MonteCarlo simulation to process and provide a graphical comparison of
probabilistic distributions for cost, payback, and other characteristics
n Offers presentation-ready reports for business case development, including charts and
tables to compare financial and technical characteristics of energy storage technologies
Objectives
DNV KEMA created this tool to help users and developers manage the
challenges and uncertainties in selecting feasible energy storage technology
options.
Benefits
ES-Select is a highly interactive model, which provides evaluation ease. Users can change all
recommended default values and add new storage technologies to the model database.
With ES-Select, users can carefully analyze the interrelated factors that influence storage
selection and the total cost of an energy storage system. It enables them to make more
informed, confident investment decisions to market and/or deploy energy storage and
progress to a smart energy future. The Sandia National Laboratories will soon offer ES-Select
on the Sandia website.
Project coordinator
n DNV KEMA, United States
Project details
n Duration July 2010 – June 2011

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Battery energy storage
system for wind energy
First Wind - Hawaii
First Wind is an independent company focused on the development, ownership and operation
of wind energy projects. First Wind planned to install wind farms throughout the islands of
Hawaii to produce clean, renewable power. However, the variable nature of renewable
generation can lead to difficulty in maintaining electricity grid operations; this problem can
become even more acute for island applications. Hence, the Hawaiian utilities established
requirements that renewable project developers must meet to qualify for interconnection.
First Wind had to meet requirements for ramp rates and potential power fluctuations, as
stipulated in the Hawaiian Electric Company’s (HECO) model power purchase agreement, to
interconnect a wind farm to the grid. First Wind examined the potential of integrating an
advanced energy storage device, since it offered characteristics that would allow the wind
farm to meet the requirements. First Wind targeted the Xtreme Power battery and sought
assistance to help confirm its evaluation of the technology, performance, and operation of the
battery storage system.

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Project
DNV KEMA’s work targeted the evaluation of the proposed battery solution to support First
Wind’s development on one of the Hawaiian Islands. DNV KEMA performed a series of tasks:
n Conducted a technology evaluation of Xtreme Power’s battery device
n Evaluated the proposed control algorithm that was being used to operate the battery
n Confirmed the sizing analysis to determine the optimal size of the battery for the project
n Reviewed factory acceptance test documents and observed actual testing at the battery
manufacturer’s site
n Confirmed the control algorithm’s ability to operate a 1MW-sized system at the First Wind
test site, located at an operational wind farm in Maui
Objectives
Due to limited availability of product performance data given the pre-commercialized state of
battery technologies, First Wind turned to DNV KEMA’s experts to help navigate it through
the process of evaluating, selecting, and sizing the battery, so it could commission operation
of the wind farm and meet requirements of HECO and project participants.
Key results
DNV KEMA’s work to support the development of a storage device enabled First Wind to
meet HECO’s requirements for grid connection. By confirming the appropriate battery size,
DNV KEMA helped First Wind to maximize wind energy storage capacity for the wind farm,
which will ensure efficient energy production. This 30-MW wind farm began operating in
March 2011. It is helping to decrease dependency on fossil fuels, thereby reducing
greenhouse gas emissions that would be harmful to the environment.
Client
n First Wind, United States
Project coordinator
n DNV KEMA, United States
Project partners
n Xtreme Power, United States
Project details
n Duration: January 2009 – October 2009

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Power to Gas:
methanation of hydrogen
The intermittent character of sustainable energy technologies, such as solar and wind
energy, affects the stability of the existing electricity infrastructure. As the installed capacity
of intermittent energy sources increases, the need for flexibility in electricity accommodation
and storage also increases. Interest has been expressed in the possible ways to use the gas
infrastructure for electricity storage, in which Europe’s extended gas infrastructure would
enable seasonal storage of electricity by the conversion of electricity into gas.
DNV KEMA acknowledges the value of the gas infrastructure to store excess electricity in
times of high production and low demand. By conversion of electricity into hydrogen (by
electrolysis), and subsequently into methane (by methanation), large amounts of energy can
be stored in the natural gas infrastructure. It enables electricity supply and demand
matching, seasonal energy storage and the production of sustainable methane without
dependence on biomass. It also enables CO 2
recycling.

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Project
In 2011 DNV KEMA started the development of a lab-scale methanation installation, in which
hydrogen (H2) and carbon monoxide/dioxide (CO/CO 2
) are converted into methane (CH4).
This process is driven by the catalytic Sabatier reaction. In the first phase of the project, tests
were performed with a nickel catalyst at temperatures of about 400°C – 500°C at ambient
pressure.
Further research will be performed with an optimized reactor with multiple methanation
reactors. Also, the pressure will be varied and temperature profiles fine tuned.
Objectives
n Identification of methanation process parameters
n Catalytic conversion of carbon dioxide and hydrogen into methane
n Carbon dioxide recycling
n Determination of catalyst performance
n Gas analysis of product gas
Project coordinator
n DNV KEMA, the Netherlands
Project details
n Duration: 2011 – Ongoing

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Zinc-Air flow batteries for
power distribution networks
POWAIR
Electricity storage systems could well be central to the future of our electricity supply.
Looking ahead, we may expect decentralized power generation to play a bigger role and the
volume of sustainable wind and solar energy to increase. The output from such power
sources is hard to control or to match with the demand, and this has implications for the
stability and quality of electricity networks.
Several technologies for local, small-scale storage are currently available or under
development. Conventional battery systems have a relatively short discharging time of about
2 hours. For storing renewable energy overnight, flow battery systems, such as Zinc-Air flow
batteries, are suitable since they can store relatively large amounts of energy and have low
self-discharge rates.

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Objectives
The project’s overall aim is to create a low-cost, modular and environmentally sustainable
electrical energy storage system with high energy density and fast response. To achieve
these aims, the project will radically extend the performance of zinc-air batteries from
small-scale single primary cells to rechargeable redox flow battery modules, which at
production scale can be stacked to give powers of 20 kW to several MW with several hours
of storage.
In tandem with the battery system, a novel distributed power converter will be developed to
enable ‘plug and play’ scale-up and hot swapping of battery modules (i.e. disconnection,
replacement and reconnection of a single battery performed without interrupting
performance of the energy storage system).
The electronics will also selectively load the battery modules to allow proactive balancing of
the batteries in a string during charge/discharge cycling and prevent any string from being
significantly limited by a single weak battery, as is the case with existing systems.
Benefits
The POWAIR technology allows large capacities of electrical energy to be stored indefinitely,
to be transmitted or distributed as and when required. The battery system can be charged
directly from the grid, for peak saving applications, or from renewable energy installations,
providing stability to the grid and eliminating the need for fossil-fuel-powered peaking plants.
Project coordinator
n C-Tech Innovation Ltd., United Kingdom
Project partners
n C-Tech Innovation Ltd., United Kingdom
n DNV KEMA, the Netherlands
n CEST Kompetenzzentrum für Elektrochemische
Oberflächentechnologie GmbH, Austria
n University of Southampton USTN, United Kingdom
Project details
n EU Seventh Framework Program
n Duration: November 2010 – November 2014
n University of Seville FIUS-GTE, Spain
n Green Power Technologies SL, Spain
n E.ON Engineering Ltd., United Kingdom
n Fumatech GmbH, Germany

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Test facilities for energy
storage systems
Matching the production of electricity to the fluctuating demand is complicated as more
renewable sources come on line. Small-scale or large-scale electricity storage creates
flexibility, thus allowing grid operation and market mechanisms to function effectively. Battery
powered (PH)EVs, e-bikes, utility-scale and ‘behind-the-meter’ energy storage will be
common place.
Project
Many of the energy storage applications do not have standardized tests. We help clients
determine the types of tests that should be performed and the right approach in designing
the actual tests for the devices and applications. DNV KEMA has a comprehensive range of
test facilities in Europe and the United States, which enables traditional and new equipment
to be qualified for permanent or flexible connection to the electricity grid. Our laboratories are
equipped to perform tests at any voltage level, including tests for PV storage systems,

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inverters and charge controllers. On top of that, we use simulating software to assess ESSs
for their specific applications.
Benefits
The successful introduction of any given system needs to ensure electrical and chemical
safety of the technology and product. Storage is utilizing new and potentially hazardous
materials and technologies. Impact, shock, short-circuit, and overcharge testing are often
applied at the cell- or stack-size level. For the different energy storage systems and battery
types, a number of standards exist for safety. Depending on the size, chemistry and
application, one of the IEC or UL standards apply. DNV KEMA, both in Netherlands and the
United States, has the capability to conduct AC and DC tests at different voltage levels
(LV-MV-HV) .
Performance tests typically examine how far a storage device can be pushed. This ultimately
determines which technology option and application to choose. DNV KEMA helps analyze
how wella storage device of thousands of individual cells is configured, engineered and
managed.Tests generally can be done at the manufacturer level, focusing on rated capacity,
cycletesting versus operating conditions, and efficiency.
To provide insights into the performance of a complete system, DNV KEMA can perform a
large variety of tests on any DC current energy source (storage system, PV, fuel cell, …).
We offer performance testing and simulation of user profiles at different voltage and current
levels. The DC cell and module test levels go up to 40 kW per testing circuit with current
ranging from 0.05 to 400 Ampere, and voltage levels from 0 to 100 Volt DC. The Flex Power
Grid Lab can go up to 1 MW(DC) or 2 MVAR(AC) of apparent power with voltage levels up to
10 kV.
DNV KEMA can also carry out field tests with its 2 MW AC field test facility. Our site
acceptancetesting (SAT) solutions help ensure energy storage systems meet performance
specificationsafter field installation. The increasing application and penetration of
grid-connected batterysystems inevitably raises the demand for testing of the behavior of
the equipment and itsinteraction with the power grid.
Project coordinator
n DNV KEMA, the Netherlands, United States
Project details
n Duration: 2008 – Ongoing

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Grid reliability and operability
using flexible storage
GROW-DERS
Connecting newly developed sustainable, dispersed energy resources to the electricity
distribution networks has significant implications for the management of these networks.
Problems are liable to arise with stability, security, supply and demand peaks, and overall
management.
Many technical and economic issues associated with the large-scale introduction of
distributed, sustainable energy sources can be solved by using electricity storage systems.
However, end users are not showing much interest in the deployment of storage
technologies. This can probably be attributed to a lack of familiarity with the technology, lack
of confidence, and uncertainty about the costs and benefits. Moreover, network components
are designed for a technical and economic service life of 40 years, and this also encourages
conservatism.

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Project
GROW-DERS offers a solution involving transportable and flexible storage based on newly
developed power electronics. The project demonstrates the technical feasibility and
economic viability of storage systems. At four sites, three different storage systems and a
combination set-up have been demonstrated. The benefits of storage systems in these
situations have been evaluated using a technical-economic assessment tool that
incorporates intelligent prediction software. This software tool (called PLATOS) was
developed within the GROW-DERS project and validated with the results of the field tests.
Objectives
The scientific and technological objectives of GROW-DERS are:
n To realize a transportable, flexible storage system
n To realize an assessment tool for optimum distribution-network management
n To formulate a description of concept directions for the EU regulatory framework
The consortium provided four different test sites for the project. Each of the storage systems
was tested at a minimum of two different sites, thus providing proof that storage systems
can be transported and operated in various locations. The project realized three
transportable, flexible storage systems and demonstrated the technical benefits of these
systems. Moreover, it realized an assessment tool for optimum distribution-network
management (PLATOS), and completed a description of concept directions for the EU
regulatory framework.
Project coordinator
n DNV KEMA, the Netherlands
Project partners
n Liander, the Netherlands
n SAFT, France
n IPE, Poland
n EAC, Cyprus
n Iberdrola, Spain
n MVV, Germany
n INES, France
n Exendis, the Netherlands
Project details
n EU Sixth Framework Program
n Duration: September 2007 – June 2011

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Modular electricity storage
system
Metal-air redox flow battery
Electricity storage systems are an important element in enabling our electricity supply’s
sustainable future. Looking ahead, we may expect decentralized power generation to play a
bigger role and the volume of wind and solar energy to increase. The output from such
renewable energy sources is hard to control or match with demand, and this has implications
for the stability and quality of electricity networks. Several technologies for local, small-scale
storage are currently available or under development. However, for large-scale systems
(more than 100 MWh) the only feasible options today are pumped storage and compressed
air energy storage (CEAS). Systems based on these technologies have a major geographical
impact. For medium- to large-scale electricity storage, the redox flow battery is an attractive
alternative.
Redox flow storage units of the first and second generation need a reactor with an expensive
membrane and two large vessels with electrolytes in an acidic environment. With all the

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controls and auxiliary equipment, the capital cost of such a system works out to about € 100
per kWh.
Objectives
The objectives of this metal-air redox flow project are to find a way to use oxygen from the
ambient air as the cathode-side reactant and to develop membranes that are easy and
cost-effective to produce on a large scale. If these objectives are realized, the resulting
third-generation redox flow systems should provide power at about € 50 per kWh – half the
cost of the current systems.
Project phases:
n Technology survey
n Membrane development
n Development of the electrode and catalyst
n Development of a membrane-electrode assembly
n Integration of the separately developed components into one operational system
n Management, communication and dissemination
Benefits
The use of electricity storage systems will enable more sustainable generating units to be
integrated into the distribution network without compromising the quality of the electricity
supply. Metal-air technology will decrease the volume and weight of redox flow batteries and
reduce their cost, thereby making them a more viable option for medium to large-scale
energy storage applications.
Project coordinator
n DVN KEMA, the Netherlands
Project partners
n University of Twente, European Membrane Institute (EMI), the Netherlands
n MAGNETO Special Anodes, the Netherlands
Project details
n EOS-LT Program
n Duration: January 2006 – December 2011