A Review of Hybrid Solar–Fossil Fuel Power Generation Systems and Performance Metrics

Abstract

A literature review of hybrid solar–fossil fuel power generation is given with an emphasis on system integration and evaluation. Hybrid systems are defined as those which use solar energy and fuel simultaneously, thus excluding the viable alternative of solar thermal plants which use fossil fuels as backup. The review is divided into three main sections: performance metrics, the different concentrated solar receiver technologies and their operating conditions, and the different hybridization schemes. In addition, a new linear combination metric for analysis of hybrid systems, which considers trade-off of different metrics at the fleet level, is presented. This metric is also compared to alternative metrics from multi-objective optimization. Some previous work only evaluates the hybrid cycle at a certain point in time, which can be misleading as this evaluation would not take into account certain aspects of hybrid cycle, such as fluctuating solar supply. Furthermore, almost all previous work designs the hybrid solar–fossil fuel systems for a certain point in time and then evaluates the performance of the system for an entire year. By not taking into account fluctuating solar supply and selling price of electricity in the design of the system, the best possible annual performance of the hybrid cycle may not be reached.

Redox reforming based, integrated solar-natural gas plants: Reforming and thermodynamic cycle efficiency

“…Typical design solar shares range between 10% and 30% [2]. Note that this input solar share is merely for a certain design hour, and the actual value changes throughout the day/year.…”

“…Within this concept of hybrid solar-fossil fuel power plants, there are three schemes: 1) solarized gas turbine, 2) solar steam integration, and 3) solar reforming [2]. A schematic of these schemes is shown in Figure 1.…”

“…The solar reforming approach involves using the solar energy to reform the fuel (natural gas) into syngas (which has a higher heating value) which is then used as a fuel for the gas turbine. The various hybridization schemes have been extensively reviewed in [2].…”

Dry redox reforming hybrid power cycle: Performance analysis and comparison to steam redox reforming

“…One potential solution for these problems is hybrid solarfossil fuel power generation. With the hybrid operation, intermittency concerns are eliminated as fuel can be used when solar is not available, and in particular, when solar reforming is used as the hybridization method, a viable storage option is obtained through the use of solar fuels [2]. Moreover, analysis of solar reforming hybrid cycles has shown that the hybridization can improve the solar energy system performance [3].…”

“…System level studies have also been performed for steam and redox reformer hybrid cycles [2,3,18]. Specifically for the redox reformer hybrid cycle, the previous analysis done was for a reformer utilizing steam in the oxidation step [18].…”