Direct Solar Energy
CSP Lifecycle GHG Emissions by Technology
Lifecycle GHG Emissions [g CO eq / kWh]
75th Percentile Median
25th Percentile Minimum
Figure 3.15 | Lifecycle GHG emissions of CSP technologies (unmodified literature values, after quality screen). See Annex II for details of literature search and citations of literature contributing to the estimates displayed.
of as-published estimates of lifecycle GHG emissions. The majority of estimates fall between 14 and 32 g CO2eq/kWh for trough, tower, Stirling and Fresnel systems, and no great difference between technolo- gies emerges from the available literature. Less literature is available to evaluate CSP systems than for some PV designs; however, the current state of knowledge of lifecycle GHG emissions for these technologies appears fairly consistent, although augmentation with additional LCAs is recommended.
In solar fuel production, solar thermal processes use concentrated solar irradiance as the main or sole source of high-temperature process heat. Such a plant consists of a central-receiver system comprising a heliostat field focusing direct solar irradiance on a receiver mounted on a tower. The receiver comprises a chemical reactor or a heat-exchanging device. Direct CO2 emissions released by the thermochemical processes are negligible or significantly lower than from current processes (Pregger et al., 2009). All other possible effects are comparable to the conventional processes or can be prevented by safety measures and equipment that are common practice in the chemical industry.
Solar energy has the potential to meet rising energy demands and decrease GHG emissions, but solar technologies have faced resistance due to public concerns among some groups. The land area requirements for centralized CSP and PV plants raise concerns about visual impacts,
which can be minimized during the siting phase by choosing locations in areas with low population density, although this will usually be the case for suitable solar sites anyway. Visual concerns also exist for distributed solar systems in built-up areas, which may find greater resis- tance for applications on historical or cultural buildings versus modern construction. By avoiding conservation areas and incorporating solar technologies into building design, these conflicts can be minimized. Noise impacts may be of concern in the construction phase, but impacts can be mitigated in the site-selection phase and by adopting good work practices (Tsoutsos et al., 2005). Community engagement through- out the planning process of renewable projects can also significantly increase public acceptance of projects (Zoellner et al., 2008).
Increased deployment of consumer-purchased systems still faces bar- riers with respect to costs, subsidy structures that may be confusing, and misunderstandings about reliability and maintenance requirements (Faiers and Neame, 2006). Effective marketing of solar technologies— including publicizing impacts relative to traditional power generation facilities, environmental benefits and contribution to a secure energy supply—have helped to accelerate social acceptance and increase willingness to pay (Batley et al., 2001). Government spending on solar technologies through fiscal incentives and R&D could garner increased public support through increased quantification and dissemination of the economic impacts associated with those programs. A recent study comparing job impacts across energy technologies showed that solar PV had the greatest job-generating potential at an average of 0.87 job- years per GWh, whereas CSP yielded an average of 0.23 job-years per GWh, both of which exceeded estimated job creation for fossil tech- nologies (Wei et al., 2010). Section 9.3.1 discusses qualifications and limitations of assessing the job market impact of RE.
Solar technologies can also improve the health and livelihood opportu- nities for many of the world’s poorest populations. Solar technologies have the potential to address some of the gap in availability of mod- ern energy services for the roughly 1.4 billion people who do not have access to electricity and the more than 2.7 billion people who rely on traditional biomass for home cooking and heating needs (IEA, 2010d; see Section 9.3.2).
Solar home systems and PV-powered community grids can provide eco- nomically favourable electricity to many areas for which connection to a main grid is impractical, such as in remote, mountainous and delta regions. Electric lights are the most frequently owned and operated household appliance in electrified households,and access to electric light- ing is widely accepted as the principal benefit of electrification programs (Barnes, 1988). Electric lighting may replace light supplied by kerosene lanterns, which are generally associated with poor-quality light and high household fuel expenditures, and which pose fire and poisoning risks. The improved quality of light allows for increased reading by household members, study by children, and home-based enterprise activities after dark, resulting in increased education and income opportunities for the