Solar roadmap

Concentrating solar power holds significant potential for the Australian energy industry. Energy Source & Distribution looks at the latest International Energy Agency solar report and the consortiums shortlisted for the Federal Government’s Solar Flagships program.

Eight projects were shortlisted in May for the second stage of assessment under the Federal Government’s $1.5 billion Solar Flagships program.

The Government intends to announce two final successful applicants – one solar thermal and one solar photovoltaic – in the first half of 2011.

The Solar Flagships program is part of the Australian Government’s $5.1 billion expanded Clean Energy Initiative. The Government’s aim is to establish up to 1000 MWs of solar power generation capacity.

Fifty-two proposals were received under round one of the program. Government funding for feasibility studies will enable these companies to develop project proposals for final assessment and project selection by the Solar Flagships Council. Of these 52 proposals, the independent Solar Flagships Council recommended eight projects after a rigorous assessment against the Solar Flagships eligibility and merit criteria.

Stage two of the application process will involve more detailed work by each of the applicants for their shortlisted projects. This will include final selection of sites; community consultation and site approvals; evaluation of solar radiation data; network connections; and finalisation of financial information – including electricity off-take agreements; engineering, procurement and construction (EPC) contracts; and project financing.

Although the projects propose different technologies, they are each capable of providing the foundation for large-scale, grid-connected, solar power to play a significant role in Australia’s electricity supply and operate within a competitive electricity market.

The International Energy Agency (IEA) recently indicated solar electricity could represent up to 20 per cent to 25 per cent of global electricity production by 2050. According to the IEA’s roadmaps, concentrated solar power (CSP) can be expected to become a competitive source of bulk power in peak and intermediate loads by 2020, and of base-load power by 2025 to 2030.

“The possibility of integrated thermal storage is an important feature of CSP plants, and virtually all of them have fuel-power backup capacity. Thus, CSP offers firm, flexible electrical production capacity to utilities and grid operators while also enabling effective management of a greater share of variable energy from other renewable sources (e.g. photovoltaic and wind power),” the roadmap states.

The IEA states concerted action by all stakeholders and government leadership is critical in order to create a favourable climate for industry and utilities and stimulate investment on the scale required to support research, development, demonstration and deployment.

The IEA believes it is necessary for governments to undertake long-term funding for additional RD&D in all main CSP technologies and component parts, including mirrors/heliostats, receivers, heat transfer and/or working fluids, storage, power blocks, cooling, control and integration, applications and at all scales (bulk power and decentralized applications).

Other necessary initiatives include facilitating the development of ground and satellite measurement of global solar resources and supporting CSP development through long-term oriented, predictable solar-specific incentives. These could include any combination of feed-in tariffs or premiums, binding renewable energy portfolio standards with solar targets, capacity payments and fiscal incentives. The roadmap also recommends streamlining procedures for obtaining permits for CSP plants and access lines.

Where appropriate, the IEA suggests state-controlled utilities should be required to bid for CSP capacities. It will also be necessary to avoid establishing arbitrary limitations on plant size and ratios, and procedures should be developed to reward only the electricity deriving from the solar energy captured by the plant, not the portion produced by burning backup fuels.


 

Shortlisted Solar Flagships programconsortiums

AGL

AGL, in collaboration with First Solar and Bovis Lend Lease, is developing up to five solar photovoltaic (PV) projects with a total capacity of up to 200 MW AC in up to five different states and territories. AGL has not yet finalised specific locations for the projects, but expects to site plants based on a combination of land availability, transmission capacity and connectivity, solar resource and state and local support. AGL will utilise First Solar’s thin film PV technology and Bovis Lend Lease will provide design and construction services for the projects, with support from First Solar.
AGL is the largest private owner, operator and developer of renewable generation in Australia and has invested well over $2 billion in renewable energy. First Solar is the world’s largest and lowest cost manufacturer of thin film PV modules, with an annual manufacturing capacity of over 1200 MW (expanding to 2100 MW by the end of 2012). Over 1500 MW of First Solar PV modules have been installed worldwide, including a 53 MW AC plant at Lieberose in Germany.

Parsons Brinckerhoff

Parsons Brinckerhoff (PB) is leading the Solar Flair Alliance, which is preparing a detailed proposal for its solar thermal power project. The Alliance’s vision is to use Australia’s abundant solar resource to provide affordable, secure and reliable electricity for all Australians. Their proposal is to develop a 150 MW solar thermal parabolic trough power plant, expected to be located near the existing Kogan Creek power station, close to Chinchilla in Queensland.

The Solar Flair Alliance, a consortium championing parabolic trough technology, is comprised of PB, CS Energy, Siemens, John Holland, Infrastructure Capital Group, the Queensland University of Technology and Curtin University.

PB and its consortium partners will receive federal funding for further studies for the Kogan Creek solar thermal power project as part of the program.

PB managing director, Dr Jim Mantle said the consortium team will conduct the feasibility and design study for the next stage of the program.

“Our task now is to prepare a detailed proposal for a 150 MW solar parabolic trough power plant at Kogan Creek, Queensland. The Solar Flair Alliance proposal has three major advantages. First, the team has extensive global experience and a local track record with their work at Kogan Creek power station. Second, the Kogan Creek site provides capital cost savings with its location next to the existing power station where it can share the established infrastructure. Third, we are recommending proven Siemens technology, currently used in Europe and the United States but new to Australia.

“Our aim is also to broaden Australia’s solar industry capacity and help position Queensland as a global leader in solar thermal energy,” Dr Mantle said.

Wind Prospect CWP

Wind Prospect CWP has formed a consortium with CS Energy, AREVA Solar and Mitsui & Co (Australia) to develop, build and operate a stand alone, 250 MW solar thermal power plant at Kogan Creek, near Chinchilla in Queensland. The power plant will incorporate AREVA Solar’s compact linear fresnel reflector (CLFR) technology, originally developed in Australia by Ausra.

Wind Prospect CWP, CS Energy, AREVA Solar and Mitsui & Co are to form a joint venture to develop, construct, own and operate the project. Wind Prospect CWP will have the lead role in project development, project permitting, solar resource assessment and financial advisory services. Mitsui will have a lead role in the design, procurement and delivery of the electricity generation part of the plant, as well as providing significant input to achieve the most optimal commercial and financial structure for the delivery of the consortium’s bid. CS Energy’s contribution to the consortium will include operating and maintaining the project in the long term. The University of Queensland will be the EIF research partner in the project.

Infigen Suntech

Infigen Energy, an Australian specialist renewable energy business, and Suntech Power Holdings, a leading producer of crystalline silicon solar photovoltaic modules, have formed a consortium to build solar power plants with a capacity of between 150 MW and 195 MW AC at up to three sites in Victoria or NSW. The photovoltaic (PV) project will incorporate solar panels that utilise Suntech’s latest-generation solar cell technology, developed in collaboration with the University of New South Wales (UNSW). Phoenix Solar and Tenix have been identified as the EPC contractors for the project and UNSW will be the research partner.

Infigen Energy is a leading specialist renewable energy business. Infigen Energy has five wind farms in Australia with a total capacity of 508 MW and also owns and operates wind farms in the US and Germany, taking its global wind energy business interests to 35 wind farms with a total capacity of 2194 MW. Suntech is the world’s largest crystalline silicon PV manufacturer. Suntech’s Pluto solar panels are based on technology that was developed at UNSW. Phoenix Solar is a German-based PV systems integrator and Tenix is an Australian-based power asset services provider offering turnkey solutions for network connection assets.

BP Solar

BP Solar is leading a consortium of experienced and established corporations to develop, construct, own and operate a 150 MW photovoltaic (PV) facility in the NSW Tablelands. The facility will use crystalline silicon technology optimised on trackers to maximise capacity factor. This technology platform, using industry-proven low degradation modules, will deliver a dependable power generation asset.

BP Solar, part of BP – one of the largest energy companies in Australia and globally – designs, manufactures and installs complex, utility-scale energy solutions and currently has major PV plants operating in the US, Europe and Asia. For Solar Flagships, BP Solar together with Fotowatio, will act as investor, developer, EPC contractor and O&M service provider, leveraging global utility plant knowledge coupled with significant Australian experience and presence. BP Solar will be working closely with the NSW Government and its research partner to develop this landmark project.

ACCIONA Energy

ACCIONA Energy proposes to generate 200 MW using solar thermal parabolic trough technology at a single site in either Queensland or South Australia. The proposed Queensland site (Capricorn Solar) is situated in the Lilyvale region, north-east of Emerald in central Queensland. The proposed South Australian site (Frontier Solar) is located in the region of Roxby Downs and the Olympic Dam mine.
ACCIONA Energy leads a project consortium with demonstrated strong capabilities in design, construction, project financing, operations and maintenance. The consortium comprises ACCIONA Energy and its subsidiaries, Mitsubishi Corporation, ACCIONA Infrastructures, Australia’s BMD Constructions and Australian engineering firm, GHD. The application of local research and development expertise will be realised through a research team lead by CSIRO.

Transfield

A consortium consisting of Transfield Holdings, Novatec (a subsidiary of Transfield Holdings), Transfield Services and the Transfield Services Infrastructure Fund plan to convert the existing coal-fired Collinsville power station in north Queensland to a 150 MW solar thermal station.

Collinsville power station has been owned and operated by members of the Transfield consortium since 1996. The converted power station will produce power using steam generated from Novatec’s award winning Nova-1 linear fresnel solar field, superheated using natural gas. Fabrication of the solar boiler, including manufacture of over one million square metres of primary reflectors, will be done locally.
Novatec’s Linear Fresnel Solar Field is a direct steam generator consisting of banks of parallel rows of flat mirrors (primary reflectors), each bank reflecting and focussing solar radiation onto a focal line. Along this line a receiver is installed, which consists of a secondary reflector and absorber pipe. Water, flowing through the absorbers, turns into steam, which is collected in a steam drum and dispatched to a steam turbine/generator. By comparison, conventional solar thermal power plants use oil as a heat transfer medium.


 

Solar technologies for power production

According to the International Energy Agency’s concentrating solar power (CSP) technology roadmap released in May, at present there are four main CSP technology families, categorised by the way they focus the sun’s rays and the technology used to receive the sun’s energy. The technologies discussed in the roadmap – parabolic troughs, linear fresnel reflectors, solar towers and parabolic dishes – are shown below.

Parabolic troughs (line focus, mobile receiver)

Parabolic trough systems consist of parallel rows of mirrors (reflectors) curved in one dimension to focus the sun’s rays. The mirror arrays can be more than 100 m long with the curved surface 5 to 6 m across. Stainless steel pipes (absorber tubes) with a selective coating serve as the heat collectors. The coating is designed to allow pipes to absorb high levels of solar radiation while emitting very little infra-red radiation. The pipes are insulated in an evacuated glass envelope. The reflectors and the absorber tubes move in tandem with the sun as it crosses the sky.

Linear Fresnel reflectors(line focus, fixed receiver)

Linear fresnel reflectors (LFRs) approximate the parabolic shape of trough systems but by using long rows of flat or slightly curved mirrors to reflect the sun’s rays onto a downward-facing linear, fixed receiver. A more recent design, known as compact linear fresnel reflectors (CLFRs), uses two parallel receivers for each row of mirrors and thus needs less land than parabolic troughs to produce a given output.

The main advantage of LFR systems is that their simple design of flexibly bent mirrors and fixed receivers requires lower investment costs and facilitates direct steam generation (DSG), thereby eliminating the need for – and cost of – heat transfer fluids and heat exchangers. LFR plants are, however, less efficient than troughs in converting solar energy to electricity and it is more difficult to incorporate storage capacity into their design.

Solar towers (point focus, fixed receiver)

Solar towers, also known as central receiver systems (CRS), use hundreds or thousands of small reflectors (called heliostats) to concentrate the sun’s rays on a central receiver placed atop a fixed tower. Some commercial tower plants now in operation use DSG in the receiver; others use molten salts as both the heat transfer fluid and storage medium.

The concentrating power of the tower concept achieves very high temperatures, thereby increasing the efficiency at which heat is converted into electricity and reducing the cost of thermal storage. In addition, the concept is highly flexible; designers can choose from a wide variety of heliostats, receivers, transfer fluids and power blocks. Some plants have several towers that feed one power block.

Parabolic dishes (point focus, mobile receiver)

Parabolic dishes concentrate the sun’s rays at a focal point propped above the centre of the dish. The entire apparatus tracks the sun, with the dish and receiver moving in tandem. Most dishes have an independent engine/generator (such as a Stirling machine or a micro-turbine) at the focal point. This design eliminates the need for a heat transfer fluid and for cooling water.

Dishes offer the highest solar-to-electric conversion performance of any CSP system. Several features – the compact size, absence of cooling water, and low compatibility with thermal storage and hybridisation – put parabolic dishes in competition with PV modules, especially concentrating photovoltaics (CPV), as much as with other CSP technologies. Very large dishes, which have been proven compatible to thermal storage and fuel backup, are the exception. Promoters claim that mass production will allow dishes to compete with larger solar thermal systems.