Memorandum 59
Submission from the Royal Society of Chemistry
The Royal Society of Chemistry (RSC) greatly
welcomes the opportunity to comment on the Select Committee on
Innovation, Universities and Skills inquiry into renewable electricity-generation
technologies. This submission has been written from the perspective
of the Royal Society of Chemistry and consequently our comments
relate to only parts of the consultation document.
The RSC is the largest organisation in Europe
for advancing the chemical sciences. Supported by a network of
43,000 members worldwide and an internationally acclaimed publishing
business, our activities span education and training, conferences
and science policy, and the promotion of the chemical sciences
to the public.
This document represents the views of the RSC.
The RSC's Royal Charter obliges it "to serve the public interest"
by acting in an independent advisory capacity, and we would therefore
be very happy for this submission to be put into the public domain.
EXECUTIVE SUMMARY
1. Solar power has the potential to provide
a significant proportion of the UK electricity needs, but current
shortcomings have to be addressed. The chemical sciences will
be crucial in reducing the cost and increasing the efficiency
of solar technology through improvements to current design and
manufacture and through the development of the next generation
of technology. Ideally it will become routine to integrate solar
power into buildings through the use of specialised construction
materials.
2. Biofuels have great potential for reducing
carbon emissions but it is vital that energy used in their production
is minimised or derived from renewable resources. Bioethanol from
lignocellulosic biomass (such as wheat straw) could improve the
economics and reduce land use for biofuels in the medium term.
However significant research and development challenges remain
for chemists, biochemists and engineers. The chemical sciences
and engineering disciplines are critical in developing efficient
catalysts, separation processes, high throughput systems and additives
to maximise the effectiveness and efficiency of biofuels.
3. In order for hydrogen to become a commercial
energy vector in the future many technical barriers will have
to be overcome. In the short term it is important to develop materials
that allow safe storage and distribution of hydrogen. As demand
grows for hydrogen, it is important to develop an efficient way
of producing hydrogen that is carbon neutral in itself. Since
it is expected that steam reforming of methane with subsequent
release of CO2 is likely to be the predominant production
route in the medium-term, the development and deployment of carbon
capture and storage is vital.
4. With wider use of renewables, the need
for energy storage will increase significantly. Research into
batteries is very important, especially into cheaper and safer
electrode and electrolyte materials with better performance. Additionally,
batteries for hybrid vehicles need to become smaller, lightweight
and have a higher energy density.
5. It is important that there are sufficiently
trained and committed scientists and engineers to carry out the
research, development, demonstration and deployment of renewable
energy-generating technologies. It is also important that the
Research Councils, Technology Strategy Board, Energy Technologies
Institute and BERR work together to ensure that there are collaborative
funding mechanisms throughout the technology development pathway
that allow scientists, engineers and technologists to work together
to bring basic research through to developed products.
6. Two alternative technologies for future
energy generation could be artificial photosynthesis and blue
energy (salinity-gradient energy). This requires a long-term research
and development effort beginning now before a commercial process
can be envisaged. The technology for blue energy needs to be produced
much more cheaply for it to be competitive with existing energy
sources.
RECOMMENDATIONS FOR
GOVERNMENT
7. Long-term funding is required for fundamental
and application specific chemistry to stimulate and encourage
energy related research. Chemical sciences can play a major role
in delivering cost effective and highly efficient renewable energy
sources. Research into more efficient and less expensive materials
to construct systems for solar energy conversion into heat and
electricity are needed as well as research into improved feedstock
conversion and lightweight, durable materials and coatings for
turbines. Basic research needs to be undertaken into materials
that can be used for fuel-cells and on-board storage of hydrogen
in vehicles.
8. Additional government support (bank loans,
tax reduction, etc) is needed to help end-users transfer to low
carbon energy. Important areas of applications could be the installation
of domestic solar power devices, the replacement of obsolete domestic
electrical equipments. The government should also introduce policies
that allow net metering, by which consumers can sell surplus electricity
back to the grid.
9. It is important that there are sufficiently
trained and committed scientists and engineers to carry out research,
development, demonstration and deployment of renewable energy-generating
technologies. This could be achieved through incentives to recruit
and maintain outstanding, internationally competitive scientists
to work on energy related research in the UK. It is also important
that the Research Councils ensure that there are collaborative
funding mechanisms throughout the technology development pathway
that allow scientists, engineers and technologists to work together
to bring basic research through to developed products.
The current state of UK research and development
in, and the deployment of, renewable energy-generation technologies
including: offshore wind; photovoltaics; hydrogen and fuel cell
technologies; wave; tidal; bioenergy; ground source heat pumps:
and intelligent grid management and energy storage
Photovoltaics (solar power)
10. Solar power has the potential to provide
a significant proportion of the UK electricity needs. The chemical
sciences will be crucial in reducing the cost and increasing the
efficiency of solar technology through improvements to current
design and manufacture and through the development of the next
generation of technology, such as technology that takes advantage
of biological methods of harvesting and storing energy from light.
The UK has a strong research base in areas including understanding
and mimicking photosynthesis systems and also in dye-sensitised
and organic solar cells. Ideally it will become routine to integrate
solar power into buildings through the use of specialised construction
materials (for example roof tiles and windows) coupled to energy
storage and low energy demand devices.
11. Photovoltaic (PV) devices consist of
a semi-conducting material, currently most commonly silicon, which
convert photons into electrical current by means of the photoelectric
effect. They were developed in the 1950s to power space satellites,
but their potential for providing remote power for telecommunications,
water pumping and refrigeration rapidly increased demand for terrestrial
applications. The drawbacks of early photovoltaic technology also
became obvious, namely cost, low power density and intermittency
of operation.
12. Although prices are coming down PV systems
currently cost around 55 pence/kWh which is more than a factor
of 10 greater than current gas, coal and nuclear power plants.
A number of different technologies are at various stages of development
to both reduce the cost of solar modules and to increase their
efficiency. Over 80% of modules are currently based on crystalline
silicon. Silicon is an excellent material for solar cell production
since its technology has become highly developed as a result of
the global semiconductor market. In addition, its supply is virtually
inexhaustible and it is non-toxic, although its manufacture is
currently highly coupled to semiconductor demand. In the late
1970s and early 1980s thin films of inorganic semiconductors made
from indium tin oxide (ITO), cadmium selenide (CdSe), copper indium
diselenide (CuInSe2), amorphous silicon, thin film silicon and
titanium oxide (TiO2) were developed as potentially cheaper PV
materials. Innovative research on very thin (less than 20 atomic
layers), high efficiency silicon devices is now in progress.
13. One of the factors that keeps system
costs high for these technologies is the requirement of high temperature
processing of the semiconductor material. This, and the rapid
growth of the organic light emitting diode market, have resulted
in considerable research on PV materials based on molecular, polymeric
and nanocomposite materials. Although commercially viable efficiencies
have yet to be demonstrated, progress is rapid. In 2004 at least
two manufacturers claimed efficiencies of 5% for organic PV materials
that can be printed or sprayed on to a thin support, flexible
backing film, potentially offering considerable production cost
reductions.
14. Dye sensitised solar cells (DSCs) offer
a near market alterative system to silicon cells. These cells
were invented by Michael Grätzel and Brian O'Regan at the
École Polytechnique Fédérale de Lausanne
in the 1990s. DSCs currently have a sunlight conversion efficiency
of 11%, which is lower than that of silicon based solar cells,
however, they have a lower cost base which allows them to compete.
There is significant potential to improve the efficiency and further
reduce the cost of DSCs.
15. The growing number of uses for photovoltaic
devices, and the considerable improvements in reliability and
price have generated a market that is growing at about 25% per
annum. Although PV began by providing power to remote locations
that had no grid connection, over 50% of today's world market
is for building integrated photovoltaic (BIPV) devices that are
incorporated into the roofs and structures of buildings. Providing
governments continue to support the installation of BIPV and introduce
policies that allow net metering, by which consumers can sell
surplus electricity back to the grid, it is likely that the demand
for PV will continue to grow. As a result, many independent studies
suggest that the costs of PV will continue to fall and that it
is plausible to reduce module costs by a factor of seven or greater
by 2020—this would allow BIPV to provide electricity below
today's retail price in sunny areas of the world.
16. Useful amounts of electricity can also
be generated directly from infrared radiation using a process
called thermophotovoltaics. It is unlikely that the power of the
sun will be harnessed directly using this technology, but it is
theoretically possible. It is more likely that thermophotovoltaics
will be used to generate electricity from waste heat to boost
the efficiency of conventional thermal power generation technologies.
Hydrogen and fuel cell technologies
17. The hydrogen economy is the name given
to an economy based on hydrogen rather than carbon based fuels.
The transition to the hydrogen economy represents the biggest
infrastructure project of the 21st Century. A sustainable hydrogen
economy would offer enormous economic, social and environmental
benefits and this justifies the significant investment of resources
and capital.
18. When hydrogen (H2) is burned or used
as fuel to generate electricity in a fuel cell, the major by-product
is water. Whilst hydrogen is abundant on Earth, it is not abundant
in the form H2 and must be produced in a way that uses energy.
Therefore, H2 is potentially a significant fuel source and the
key challenges are to minimise the energy used in producing H2
and ultimately to produce H2 from sustainable sources.
19. There are technical barriers throughout
the supply chain of the hydrogen economy, and the key challenges
for the chemical sciences are highlighted in the following sections.
Hydrogen production
20. Energy is required to produce hydrogen
and therefore as a fuel it is only as clean as the process that
produced it in the first place. Currently the most common method
is steam reforming of natural gas in two-step catalytic process,
producing a mixture of H2 and CO2. There are concerns over the
economics of the process and over the release of CO2. In the future
it will be possible to employ carbon capture and storage (CCS)
technology to safely store the CO2, however, this will add to
the cost of the hydrogen production and the energy required. There
are a number of medium and long-term options for producing hydrogen:
(a) Coal and oil residues or biomass gasification.
The high temperature of the process and the need to separate nitrogen
from air (presumably cryogenically) are barriers which add to
the cost of this process.
(b) Using electricity (preferably from renewables)
to split water via electrolysis can be seen a method of storing
(renewable) power. Further work is still needed to develop improved
electrode surfaces for electrolysers and also the materials of
construction. Uses for the by-product O2 also need to found.
(c) Thermochemical splitting of water in
the next generation of high temperature nuclear reactors or concentrating
solar power plants. There is a need for new materials and an understanding
of the fundamental high temperature kinetics and thermodynamics
in order to achieve this.
(d) Biochemical hydrogen generation. Green
algae and cyanobacteria utilise light to split water, producing
both H2 and O2. Currently O2 concentration in the system and the
rate of reaction are limiting factors. New natural microorganisms
and genetically modified organisms may hold to key to increased
efficiency.
(e) Photocatalytic water electrolysis is
where the energy of sunlight is used to split water into H2 and
O2. The system, and current R&D priorities, are focused on
two basic principles. Firstly, the light harvesting system must
have suitable energetics to drive the electrolysis. Secondly the
system must be stable in an aqueous environment.
Hydrogen storage and distribution
21. Hydrogen is the lightest element and
occupies a larger volume than other fuels. Currently, in prototype
vehicles, compressed hydrogen is used, but this is relatively
bulky. Liquid hydrogen would be a more efficient way to store
H2 (850 times denser than gaseous H2) but with a boiling point
of -253°C it is very energy intensive to maintain the very
low temperature required to store hydrogen in this form. Finding
mechanisms to store hydrogen in a form that is safe, suitable
for intended use and regenerable (if applicable) is therefore
a key research priority that the chemical sciences must rise to
meet. Some of the key technologies and issues are summarised below:
(a) High surface area nanostructured materials,
such as carbon nanotubes, have been shown to be able to store
and release significant quantities of H2. Such materials are as
yet unproven and much scientific endeavour is required to fully
assess their potential.
(b) Certain metal complexes absorb H2 reversibly
to form metal hydrides. Numerous compounds have been and continue
to be studied. Key requirements of a suitable metal hydride include,
high H2 content, low cost, favourable kinetics, resistance to
poisoning and the materials should not ignite in air.
(c) There are a number of options for chemical
carriers of H2; this means that the H2 is bound into the chemical
structure of the carrier. Organic liquids, such as cyclohexane
and methanol, inorganic complex hydrides such as 3Na[AlH6] and
chemical hydrides such as NaBH4 all have potential to carry H2.
Key challenges include the mechanism of releasing H2, recharging
the materials, H2 density and cost. R&D programmes continue
to explore these issues.
22. There are a number of worldwide examples
of pipeline networks for safely moving pressurised hydrogen, thus
demonstrating that a larger scale network is possible. However,
there is an issue of compatibility of H2 with existing natural
gas infrastructures both in terms of the materials employed (potential
for leakage) and the need for a faster flow rate (requiring more
energy). The chemical sciences have a key role to play in material
design for hydrogen carrying infrastructures.
23. Hydrogen may potentially be stored in
large quantities in depleted oil and gas fields and aquifers.
There is a significant parallel here with work being carried in
the field of carbon capture and storage.
24. There have been concerns over release
of molecular hydrogen into the lower atmosphere, for example through
leakage. The presence of H2 may lead to a reduction in the levels
of hydroxy radicals ( OH). Since OH is a sink of methane (CH4)
this may lead to an increased level of CH4 in the atmosphere.
Clearly it is important that the role of H2 in the atmosphere
is better understood.
Hydrogen use
25. Aside from direct combustion, fuels
cells are the main method for obtaining energy from hydrogen.
Fuel cells (FCs) fall broadly into three categories:
— Low Temperature (50-150°C):
alkaline (AFC), proton-exchange membrane (PEMFC) and direct methanol
(DMFC) fuel cells;
— Medium Temperature (around 200°C):
phosphoric acid fuels cell (PAFC);
— High temperature (600-1,000°C):
molten carbonate (MCFC) and solid oxide (SOFC) fuel cells.
26. The DMFC differs from the other FCs
because it uses methanol as fuel, rather than H2. Each of the
six systems has preferred uses (for example stationary and mobile
power generation), advantages and disadvantages and specific research
priorities that need to be addressed. For chemical scientists
there are numerous technical challenges to be overcome including:
— Materials for construction.
— Understanding the fundamental thermodynamics
and kinetics.
— Tolerance to impurities.
— Electrocatalyst design.
27. On-board storage of hydrogen is posing
significant obstacles to delivering hydrogen-powered vehicles.
The development of materials for hydrogen storage is a key challenge
for chemical scientists.
28. The cost of fuel cells versus that of
the internal combustion engine is also a problem, with the latter
typically costing $50 for each kilowatt of power it produces while
fuel cells cost a hundred times more. Technical challenges such
as making fuel cells rugged enough to withstand the stress of
driving, reducing their size and weight while increasing power
density, fuel flexibility and fuel cell poisoning still exist.
29. The RSC believes that for the hydrogen
economy to become a reality, major scientific and engineering
challenges need to be addressed in terms of the generation of
hydrogen on a large scale, storage, cost-effective safe transportation
and the next generation of materials and technology for hydrogen
fuel cells. We recommend that the Government supports the science
and engineering research that will ultimately deliver a sustainable
hydrogen economy at a level where the UK is in competitive position
in a world perspective.
Bioenergy
30. First generation biofuels, that is those
derived from starch or sugar crops (bioethanol) or those derived
from vegetable or animal oils (biodiesel) are already a mature
technology. There are certain technological advances, for example
pervaporation membranes for bioethanol purification and high throughput
continuous reactors for biodiesel production, that could improve
the efficiency of their production.
31. It is the belief of the RSC that second
generation biofuels (eg bioethanol, biobutanol and fuels produced
from synthesis gas such as gasoline and diesel) that are derived
from lignocellulosic biomass (such as cereal straw, trees, waste
paper, etc) offer far greater potential for reducing cost and
environmental impact compared to first generation biofuels. Furthermore,
second generation biofuels do not necessarily compete with food
production unlike first generation biofuels. There are a number
of key technological barriers that must be overcome before second
generation biofuels are realised and these are addressed in our
response. The chemical sciences and engineering disciplines are
critical in developing efficient catalysts, separation processes,
high throughput systems and additives to maximise the effectiveness
and efficiency of biofuels.
32. There are currently many options for
the generation of energy from potential materials. The best of
these, including the biorefinery approach, not only produces matter
for power generation but also potentially valuable co-products.
Given the restriction of available land area, there is great potential
in exploiting the extensive marine resources at the disposal of
the UK for biomass production, a process which serves multiple
beneficial roles beyond that served by the end product.
33. Carbon emissions from the use of biomass
or derived products should ideally be equal to that sequestered
during the growth of the source material making the process carbon
neutral. However, this depends crucially upon the energy used
in processing and production, and the logistics and efficiency
of agricultural, chemical, biochemical and engineering practices
employed. Biomass is most effective in reducing CO2
when the supply chain distance is minimal. This means that importing
biomass should be considered carefully in this respect in addition
to the ethical and security implications involved. Furthermore,
achieving sustainability during production would be greatly helped
by the publication of best practice guidelines for agriculture.
34. Economic factors will drive the success
of bioenergy so making this option competitive is essential. Research
into the practicalities of scale, efficiency and logistics as
well as the creation of an appropriate long-term policy and finance
framework based upon this research to support bioenergy in the
UK is clearly needed. The potentials for bioenergy are unlikely
to be exploited under prevailing economic conditions and sectorial
approaches. There must be strong links between all those involved
including academic research, agricultural production, industrial
refining and end users be they public retailers or power companies.
35. The RSC has recently submitted evidence
to two relevant inquiries, the EFRA Committee inquiry into bioenergy
(appendix A (not printed)) and the Royal Society inquiry into
biofuels (Appendix B (not printed)). Both documents are attached
to this submission as appendices.
Energy Storage—Batteries
36. Rechargeable batteries offer the most
direct means of storing electrical energy and as a result are
highly efficient.
37. Lithium-ion batteries represent the
most important development in rechargeable battery technology
for a hundred years. They have three times the energy density
of conventional rechargeable batteries and have had a major impact
in consumer electronics. A lithium-ion battery occupying some
10 m3 could store 4.5 MWh of energy and with a charge/discharge
efficiency of over 99.9%. This technology is already the storage
solution of choice in a number of energy research centres around
the world.
38. Lithium-ion technology presents one
of the greatest challenges for chemists. Scale up to larger batteries
requires:
— fundamental advances in new cheaper,
safer electrode and solid polymer electrolyte materials with better
performance; and
— new non-flammable liquid electrolytes
or ionic liquids.
39. Moreover, Li-ion batteries for vehicles
are comprised of hundreds of cells, if any of these fails the
whole system is compromised.
40. Cobalt oxide is a key material for producing
lithium ion batteries. The world estimated cobalt reserves are
relatively small; less than a tenth of that of nickel and just
over a hundredth of that of copper. Cobalt accounts for a quarter
of the mass of lithium ion batteries. If 30 million battery packs
capable of powering electric vehicles were made annually the world
cobalt reserves would be depleted in six years (provided the global
estimates are accurate). The majority of cobalt reserves are located
in politically unstable regions—the top three sources of
cobalt are Congo, Cuba and Zambia. This could raise a major security
of supply issue. To address this electrodes based on cheaper more
abundant materials must be synthesised.
41. A further possible driver for the development
of novel battery technology at the smaller scale end of battery
technology is regulation. In the EU, measures have already been
taken to limit the mercury content of batteries. Further regulation
will aim to reduce other heavy metals, including cadmium, nickel
and lead. Also options for disposal of batteries will be limited
to encourage collection and recycling.
Energy Storage—Superconductors
42. In superconducting magnetic energy storage
devices (SMES), energy is stored in the magnetic field of a coil
within which a current flows. The device consists of a superconducting
coil, typically made of niobium with titanium or tin, in a copper
matrix, a power conditioning system (PCS), a refrigeration system
for cooling the coil and a cryostat vacuum vessel. Efficiency
losses are mainly due to the cryogenic system, which has to keep
the coil below the critical superconducting temperature of around
-268°C.
43. Chemists are needed to address the identification
and development of new superconducting materials with higher critical
temperatures, preferably room temperature, and with suitable mechanical
properties for processing into coils and wires.
Wind, tidal and wave power
44. Advances in materials science to develop
high strength, lightweight materials for turbine blades and towers
are required in order to facilitate the construction and continued
operation of large wind and tidal power turbines. Long lasting
protective coatings will also be required to reduce maintenance
costs and prolong the operating life of wave and tidal energy
devices.
The feasibility, costs, timescales and progress
in commercialising renewable technologies as well as their reliability
and associated carbon footprints
45. No comment.
The UK Government's role in funding research and
development for renewable energy-generation technologies and providing
incentives for technology transfer and industrial research and
development
46. It is important that there are sufficient
trained and committed scientists and engineers to carry out the
research, development, demonstration and deployment of renewable
energy-generating technologies. It is also important that the
Research Councils, Technology Strategy Board, Energy Technologies
Institute and BERR work together to ensure that there are collaborative
funding mechanisms throughout the technology development pathway
that allow scientists, engineers and technologists to work together
to bring basic research through to developed products.
47. The relatively short timescales (three
years) of research council funding is seen as a major weakness
in the context of the long-term challenge of sustainable energy
research. It leads to a lack of continuity in academic research
and a short term attitude. In terms of funding, responsive mode
funding is viewed as being of vital importance to foster new discoveries
and support high quality research. Such responsive mode funding
needs to be long term five to eight years rather than two to three
years. However, responsive mode funding alone cannot address the
strategic imperatives in research for sustainable energy technologies.
It is felt that responsive mode funding must be complemented with
more targeted, focused funding and especially long term support
to stimulate more materials research for sustainable energy technologies.
48. There is a real need to bridge the "development"
gap between academic research and prototyping. Large-scale collaboration
is required to drive breakthroughs. As well as the cultural divide,
the "development gap" is linked to a lack of funding
for development. Whilst the decline in large-scale corporate R&D
investment reflects a global trend, this decline is felt particularly
acutely in the UK where large-scale industrial research was previously
very strong. Opportunities to collaborate with industry and the
availability of additional industry funding are no longer as widely
and readily available. Funding is required to support research
as it moves from the laboratory into technology development. Tax
breaks and other financial incentives should be offered to encourage
industry to invest in sustainable energy technologies.
49. The RSC has recently submitted responses,
relevant to this inquiry, to the Sainsbury review of science and
technology consultation (Appendix C (not printed)) and the EPSRC
knowledge transfer and economic impact consultation (Appendix
D (not printed))—these are attached as appendices.
Other possible technologies for renewable energy-generation
Artificial photosynthesis
50. Artificial photosynthesis is a research
field that attempts to replicate the natural process of photosynthesis,
converting sunlight, water and carbon dioxide into carbohydrates
and oxygen. The process essentially comprises two steps one involving
a light reaction and other a dark reaction. In the first step
light is captured and the energy used to split water into oxygen
and hydrogen. In the second "dark" step hydrogen is
combined with carbon dioxide to make carbohydrates (or possibly
other products). The potential of artificial photosynthesis is
huge as it offers a route to sustainable hydrogen production and
also potentially to a process that removes carbon dioxide from
the atmosphere and creates useful products. The scientific and
technical challenges, however, are equally large—in essence
this is because the natural process is incredibly complex and
comprises of numerous interlinked processes. Artificial photosynthesis
will require a number of years of research and development before
a commercial process is envisaged.
Blue energy
51. A significant potential to obtain clean
energy exists from mixing water streams with different salt concentrations.
This salinity-gradient energy, also called blue energy, is available
worldwide at estuaries where fresh water streams flow into the
sea. The global energy output from estuaries is estimated at 2.6TW,
which represents approximately 20% of the present worldwide energy
demand. Large amounts of blue energy can also be made available
from natural or industrial salt brines.
52. Blue energy can work either on the principle
of osmosis (the movement of water from a low salt concentration
to a high salt concentration) or electrodialysis (the movement
of salt from a highly concentrated solution to a low concentrated
solution) where the saline water and fresh water be separated
by a selectively permeable membrane. In the osmosis process water
pressure is created that can drive a turbine. In the electrodialysis
case the movement of ions creates the electricity. The by-product
of blue energy is brackish water. Brackish water is simply a combination
of fresh and salt water which naturally occurs in an estuary.
53. Though the technology of blue energy
has been understood for quite sometime, manufacturing the membranes
was far too expensive for this to become a practical energy alternative.
Recently, more economical membranes have been developed which
will allow blue energy technology to begin being implemented in
suitable environments. Further developments that reduced the cost
or improved the efficiency of membranes would significantly improve
the economics of this process. Currently blue energy is being
used successfully in the Netherlands.
January 2008
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