Solid Oxide Fuel Cells for High Efficiency Domestic Combined Heat and Power
Submitting Institution
Imperial College LondonUnit of Assessment
Electrical and Electronic Engineering, Metallurgy and MaterialsSummary Impact Type
TechnologicalResearch Subject Area(s)
Chemical Sciences: Physical Chemistry (incl. Structural), Other Chemical Sciences
Engineering: Materials Engineering
Summary of the impact
Patents arising from EPSRC funded research by Kilner (PI) and Steele,
Atkinson and Brandon
(CoI's) resulted in the development of a unique metal-supported solid
oxide fuel cell and formation
of the spin out company Ceres Power in 2001. Ongoing development at Ceres
Power has been
supported by further underpinning research by the Fuel Cell group in the
Department of Materials
at Imperial and has produced a world-leading SOFC fuel cell module which
provides the core
component for a variety of applications and fuels, including: micro
combined heat and power
(mCHP); mobile auxiliary power units (APU); and remote power. Ceres Power
has developed a
mCHP unit containing the core module for residential applications powered
by natural gas in
collaboration with British Gas and Bord Gais (Ireland). The unit has an
electrical efficiency of 45%
and total efficiency of 90%. It reduces the energy bill by 25%, and saves
around 1.5 tonnes of CO2
per annum per household. The company is AIM listed and in 2011 had 160
employees, with a
technology centre in Crawley and a manufacturing plant in Horsham. Over
the period of the review
the company has directly provided approximately 600 man years of
employment in the UK.
Underpinning research
The Department of Materials at Imperial College London has a
long-established, world-leading
position in the general field of ion-conducting ceramics, with a
particular emphasis on their
application in SOFCs. A strategic theme in this research, which resulted
in the specific innovation
described here, was to reduce the SOFC operating temperature as much as
possible. In the early
1990's, there was a resurgence of interest in the solid oxide fuel cell
and the Department of
Materials (Steele, Kilner, Atkinson) began a program of research to
develop materials capable of
operating at much lower temperatures. Conventional cells operated at
between 700 and 1000ºC
and were, in the main, all ceramic devices employing brittle glass seals.
These devices were
costly and mechanically weak with durability problems caused by the high
temperatures of
operation. The goal of the research was to find a materials set that could
operate at temperatures
as low as 500ºC, where much cheaper stainless steels could be used for
support of the cell,
interconnects and for the balance of plant. Through a basic research
programme, this materials
set was identified based around an optimised ceria gadolinia electrolyte
(reference 1), a nickel-
ceria anode and doped lanthanum ferrite (LSCF) cathode (reference 2). The
core patent behind
Ceres arose out of research conducted through EPSRC grant GR/N04638/01
OPTIMISATION
AND EVALUATION OF INTERMEDIATE-TEMP (500 C)SOLID OXIDE FUEL CELL (IT-SOFC)
STACKS (J A Kilner (PI), N P Brandon, B C H Steele, A Atkinson, all of
Imperial College London)
1st October 2000 to 31st January 2004. This focussed
on developing; the anode and cathode
material for use with ceria electrolytes; the electrode, electrolyte and
cell fabrication processes that
enabled SOFC operation at 500-600ºC; and use of a metal support to produce
a robust device free
of the need for delicate glass ceramic seals (reference 3). At that time,
a metal-supported SOFC
was a radical new concept, as was the relatively low operating temperature
of 500-600ºC for a
SOFC, and this research was the first to demonstrate a working device. Now
several companies
and research groups worldwide are pursuing metal-supported SOFC
technology, and the reduction
of operating temperatures to 500ºC, or even lower.
Core patents behind Ceres Power fuel cell module technology were filed by
Atkinson, Kilner et al.,
over the period 2000 to 2004, and subsequently granted from 2003 to 2006
(reference 4).
Subsequent to the patent filing, papers were published by Atkinson, Kilner
et al over the period
2004 onwards which addressed issues such as the properties of the LSCF
cathode (reference 5)
and the development of new materials for ITSOFCs (reference 6).
Publication of some of this
material was not possible before the patents were filed, but contributed
to the patents. Other
research has contributed to the ongoing technology development at Ceres
Power. The core
underpinning research that supported Ceres Power was carried out through a
series of EPSRC
funded programmes which included a grant to transfer the technology for
the deposition of the cells
onto the stainless steel substrates, from the Department of Materials to
Ceres Power (Optimised
thick film electrolytes for IT-SOFC manufacture, GR/S81476/01, J.A Kilner
October 2003-October
2004).
References to the research
* References that best indicate quality of underpinning research.
1. *Steele, B.C.H. "Appraisal of Ce1-yGdyO2-y/2 electrolytes for IT-SOFC
operation at 500ºC",
Solid State Ionics Volume: 129 Issue: 1-4 Pages: 95-110 (2001) DOI:
10.1016/S0167-2738(99)00319-7.
2. *Dusastre, V.,Kilner, J.A. "Optimisation of composite cathodes for
intermediate temperature
SOFC applications", Solid State Ionics, 126 [1-2] 163-174 (1999) DOI:
10.1016/S0167-2738(99)00108-3.
3. Esquirol, A., Brandon, N. P., Kilner, J. A., Mogensen, M.
"Electrochemical characterization of
La0.6Sr0.4Co0.2Fe0.8O3 cathodes for intermediate-temperature SOFCs", Journal
of the
Electrochemical Society, 151 [11] A1847-A1855 (2004) DOI:
10.1149/1.1799391.
4. B.C.H., Atkinson, A., Kilner, J.A., Brandon, N.P., Rudkin, R.A. , Fuel
Cells Steele, US patent
US6794075(B2).
Sept 21 2004. The image of the patent is archived here.
5. *Oishi, N., Atkinson, A., Brandon, N.P., Kilner, J.A., Steele, B.C.H.
"Fabrication of an anode-
supported gadolinium-doped ceria solid oxide fuel cell and its operation
at 550ºC", Journal of
The American Ceramic Society Volume: 88 Issue: 6 Pages: 1394-1396
2005 DOI:10.1111/j.1551-2916.2005.00251.x.
6. Tarancon, A., Skinner, S.J., Chater, R.J., Hernandez-Ramirez, F.,
Kilner, J.A. "Layered
perovskites as promising cathodes for intermediate temperature solid oxide
fuel cells", Journal
of Materials Chemistry 2007, 17, (30), 3175-3181 DOI:
10.1039/B704320A.
Details of the impact
The underpinning research led to the invention and patenting of a new
class of fuel cell, namely a
metal-supported SOFC operating at 500-600ºC [A,B]. The core patent has
been granted on a
worldwide basis, and further patents have followed. The key commercial
impact of the invention
was the formation of a spin-out company, Ceres Power, in 2001 which has
provided continued
employment to over 100 people amounting to approximately 600 man years
since 2008 (the review
period). The new type of fuel cell invented by the Imperial team is
particularly well suited to
operation on hydrocarbon fuels (such as natural gas, LPG and diesel
reformate) and its robust
construction allows its application, as the core fuel cell module, in
several large volume consumer
applications. Ceres Power has developed a domestic mCHP unit around the 1
kWe core fuel cell
module which operates on mains natural gas and generates all of the
heating and hot water and
the majority of the electricity needs of a typical UK home. The
wall-mounted unit is designed to
replace a conventional central heating boiler and uses the same gas, water
and electricity
connections. The unit (Figure 1) has a high electrical efficiency of 45%,
and total efficiency of 90%,
which reduces the energy bill by 25%, and saves around 1.5 tonnes of CO2
per annum per
household, thereby reducing greenhouse gas emissions. This is being
developed with British Gas
[C] and Bord Gais based on a forward order for 37,500 units. The core SOFC
module is compact,
robust, cheap, fuel-flexible and has an output that makes it suitable for
non-UK markets and other
applications. These include auxiliary power units in large trucks or small
boats, operating on
reformed diesel, and off-grid power operating on LPG for use in remote
locations or for
uninterruptable electricity supply in collaboration with Calor.
On-going research in the Materials Fuel Cell group has continued to
inform the Ceres Power
development programme through sponsored research and technical meetings
with the founders.
Ceres Power listed on the London AIM market in 2005, and in 2011 employed
around 160
technical and commercial staff in its UK manufacturing facility in
Horsham, and its technology
centre in Crawley[D]. On 25th April 2012 Ceres signed an
agreement with the Itho-Daalderop
Group B.V. to distribute Ceres fuel cell CHP products into the residential
mass market within the
Benelux countries. [E]. On restructuring of the company in 2013, staff
numbers have been
reduced and the operating costs have also been reduced by 44% to £10.2M.
Development of SOFC systems is a very competitive field of research in
terms of fundamental
science, technology development, and commercialisation. Ceres was
nominated by the Institute of
Materials Mining and Minerals for the Queen Elizabeth Prize for
Engineering in 2013 and John
Kilner was awarded the platinum medal [F]. The Imperial /Ceres development
of metal-supported
cells has had a major impact on world development of SOFCs. This was
recognised in 2012 by an
independent review of the Ceres technology undertaken by an international
expert in SOFCs Dr
Nguyen Minh [G]. Some of his findings are:
"Unique cell/stack designs based on thin stainless steel foil
interconnect and laser drilled
substrate, imparting high levels of mechanical robustness and thermal
cyclability and creating
compact, lightweight sub-systems."; "Increased cell/stack
reliability due to durable and stable seals
formed by welding and compression (vs. delicate glass seals commonly
used in conventional
SOFCs)."; "Low-cost, volume manufacturability based on
conventional processes such as metal
forming and screen printing with ability for high levels of
automation."; "Patents and know-how
covering laser drilled foil substrate, cell configuration, stack design,
manufacturing procedures and
conditions provide significant protection against competition". [G]
Because of these major advantages many researchers and developers (e.g.
Topsoe Fuel Cells,
Denmark) are currently pursuing metal-supported cell technology operating
at approximately
600°C. Thus the research in this impact statement has led the field by
approximately 10 years and
there have been many imitators (e.g. a recent EU Project METSOFC,
2008-2011). However, no
other developer has yet succeeded in matching the performance of the Ceres
Power cells. As a
result of this world-leading performance Ceres is now moving to embrace a
global market for its
products and in July of this year announced a commercial and technical
partnership agreement
with South Korea's largest boiler manufacturer, KD Navien. The press
release states "KD Navien is
the dominant boiler manufacturer in South Korea with the largest market
share of all installed
boilers. It is also a major exporter to key markets around the world,
particularly the US". [H]
In summary Ceres Power is a UK based SME, with globally leading fuel cell
technology based on
research at Imperial College London, and a strong foothold in the
burgeoning market for low
carbon technologies such as mCHP.
Sources to corroborate the impact
A. "Development of Highly Robust, Volume-Manufacturable Metal-Supported
SOFCs for
Operation Below 600°C", R. Leah, A. Bone, A. Selcuk, D. Corcoran, M.
Lankin, Z. Dehaney-
Steven, M. Selby and P. Whalen, Electrochemical Society Transactions,
35 (1) 351-367
(2011). [ISBN: 978-1-60768-236-3]
B. EPSRC case study on the impact of its research which discusses Ceres
Power and the role
played by underpinning research at Imperial College funded by EPSRC
http://www.rcuk.ac.uk/documents/energy/fuelcells.pdf.
Archived here
on 28/10/2013
C. British Gas ordered 37,500 Ceres units for the UK market and made an
investment of around
£20 million. http://www.cerespower.com/store/files/12-BG%20development%20supply%20and%20distribution%20agreement.pdf
Archived
here on
28/10/1013
D. Ceres Power "employs more than 160 people with its operations based in
the UK, comprising
a Technology Centre in Crawley and a volume fuel cell manufacturing
facility in Horsham"
page 2 Ceres Power 2011 Annual Report http://www.cerespower.com/store/files/269-Ceres%20Power%20Annual%20Report%202011%20FINAL.pdf
Archived here
on 28/10/1013
E. Itho-Daalderop will distribute Ceres fuel cell CHP products into the
residential mass market
within the Benelux countries, the third largest boiler market in the
European Union with over
650,000 units sold annually http://www.cerespower.com/store/files/285-New%20strategic%20partner%20to%20access%20Benelux%20market%20.pdf
Archived
here
on 28/10/ 13
F. Prof John Kilner Awarded the Institute of Materials, Minerals and
Mining 2012 Platinum Medal
(...His company, AIM, founded in 2000 now has over 100 employees and is
recognised as a
world leader in SOFC...". http://www.iom3.org/content/award-winners-2012
(Archived at
https://www.imperial.ac.uk/ref/webarchive/8tf)
G. Independent assessment of the Company's core technology by an
international expert in fuel
cells and related technologies. http://www.cerespower.com/store/files/292-Ceres%20Power%20technical%20update%20and%20expert%20report%2018Sep12%20FINAL.pdf
Archived here
on 28/10/1013
H. Ceres signs commercial and technical partnership agreement with South
Korea's largest boiler
manufacturer, KD Navien. http://otp.investis.com/clients/uk/ceres-power/rns/regulatory-story.aspx?cid=142&newsid=352685
(Archived at
https://www.imperial.ac.uk/ref/webarchive/0tf)