Photovoltaic solar power seems to get most of the attention when it comes to solar (for good reason), but global solar thermal electricity from concentrating solar power plants has also improved a lot in the last five years. The technology is diversifying, costs are dropping, and new markets have begun to open up. At the same time, greater uncertainty has begun to dog nuclear power and carbon capture and sequestration schemes.
The International Energy Agency has thus reassessed the roles of both solar energy sources and published its findings in a new Technology Roadmap (for) Solar Thermal Electricity released last month.
One of a series, the roadmap identifies steps government, industry, and financial partners can take to accelerate the technology changes in global solar thermal electricity. While the agency predicts reduced medium-term prospects for solar thermal electricity, its estimates for long-term prospects remain about the same as those published in 2009.
The agency looks at the rationale for solar thermal electricity in the overall global context of energy. Built-in storage capabilities make CSP plants uniquely able to supply electricity on demand. Emerging economies with growing capacity needs when demand peaks after sunset have already tapped into concentrating solar. It will attain further importance in the future as PV and wind, both variable renewable sources, increase their slices of the electricity pie. And perhaps most important of all, it preserves climate because it emits no post-installation greenhouse gases.
IEA’s global solar thermal electric roadmap reads well and is replete with explanatory exhibits: 15 figures, 6 tables, and 6 sidebars. It has also undergone international review. IEA structures the presentation in five major sections:
- The current state of the solar thermal electricity industry and progress since 2009, including the IEA’s Energy Technology Perspectives CO2 reduction targets.
- A vision for solar thermal electricity deployment between 2015 and 2050 and including information on CSP regional distribution, associated investment needs, and potential for cost reductions.
- Approaches to addressing challenges to large-scale solar thermal electricity deployment.
- Policy frameworks for development, public engagement, and international collaboration.
- Steps and actions in the next five years for policymakers, industry, power system participants, and financing organizations.
Technology improvements and development explored for global solar thermal electricity include linear systems, solar towers, thermal storage, and backup and hybridization.
Removing noneconomic barriers is another subject explored in detail.
To reach a share of global solar thermal electric power of as much as 11% in 2050, IEA geared the 35-year analysis on these milestones:
- Governments establish or update targets for CSP deployment and implement stable regulatory and market frameworks to ensure predictable financing and remuneration that reflects the value of solar thermal electricity at time of delivery.
- Industry further reduces solar thermal electricity costs through technology improvements.
- Industry and research institutions make research and development efforts commensurate with the potential of solar thermal electricity and CSP technologies to create a climate-friendly energy future.
Here’s a look at the results.
Countries must establish stable policy frameworks for investments in CSP plants to take place. Like most renewables or energy efficiency improvements, STE is very capital intensive: almost all expenditures are made upfront. Lowering the cost of capital is thus of primary importance for achieving the vision of this roadmap. Clear and credible signals from policy makers lower risks and inspire confidence. By contrast, where there is a record of policy incoherence, confusing signals or stop‐and‐go policy cycles, investors end up paying more for their investment, consumers pay more for their energy, and some projects that are needed simply will not go ahead.
Summary of near-term actions for STE stakeholders
Policymakers at international, national, regional and local levels will be involved. Their functions:
- Remove deployment barriers,
- Establish frameworks that promote close collaboration between the CSP industry and the wider power sector, and
- Encourage private sector and increased public investment.
Governments should take the lead on these actions:
- Set or update long-term targets for CSP deployment, including short-term milestones consistent with national energy strategies and with expected contributions to global climate mitigation.
- Address existing or potential barriers to deployment, in particular from permitting and connecting procedures.
- Ensure a stable, predictable financing environment. Where market arrangements and cost competitiveness do not provide sufficient incentives for investors, make sure that predictable, long-term support mechanisms exist; the level of support should, however, be progressively reduced.
- Ensure that the remuneration structure reflects the current and foreseeable structure of overall power system costs, so that developers adjust the size of solar fields, thermal storage and turbines to each country’s needs for dispatchable power in the coming decades.
- Do not arbitrarily limit the size of individual plants.
- Do not arbitrarily set the level of fossil fuel backup or solar hybridisation in fossil fuel plants, but provide STE remuneration to all – and only – solar sourced kWh for new-built plants.
- Avoid retroactive changes in legislation and support frameworks.
- Identify and provide a suitable level of public funding for CSP R&D, including STE, high-temperature solar heat for industrial processes, and solar fuels, proportionate to the cost reduction targets and potential of the technology in terms of electricity production and CO2 abatement targets.
- Enable increasing international R&D collaboration to make best use of national competencies.
- Strengthen international collaboration on best practices, and the development of resource databases open to the public.
The CSP industry includes technology providers, manufacturers, developers, engineering, procurement, and construction contractors. With support from research institutions, CSP industry action in the short term should focus on these areas:
- Develop new light-weight low-cost reflector optics.
- Demonstrate large-scale use of molten salts as HTF in linear systems.
- Further develop and optimize solar tower concepts.
- Introduce supercritical steam turbines in CSP plants.
- Market CSP technologies for high-temperature process heat.