Waste to energy efficiency improvements: Integration with solar thermal energy

2019 ◽  
Vol 37 (4) ◽  
pp. 419-434
Author(s):  
B Mendecka ◽  
L Lombardi ◽  
Pawel Gladysz

Hybridisation of waste to energy with solar facility can take competing energy technologies and make them complementary. However, realising the benefits of solar integration requires careful consideration of the technical feasibility as well as the economic and environmental benefits of a proposed system. In this work, a solar-integrated waste-to-energy plant scheme is proposed and analysed from an energy, environmental and economic point of view. The new system integrates a traditional waste-to-energy plant with a concentrated solar power plant, by superheating the steam produced by the waste-to-energy flue gas boiler in the solar facility. The original waste-to-energy plant – that is, the base case before introducing the integration with concentrated solar power – has a thermal power input of 50 MW and operates with superheated steam at 40 bar and 400 °C; net power output is 10.7 MW, and the net energy efficiency is equal to 21.65%. By combining waste-to-energy plant with the solar facility, the power plant could provide higher net efficiency (from 1.4 to 3.7 p.p. higher), lower specific CO2 emissions (from 69 to 180 kg MWh-1 lower) and lower levellised cost of electricity (from 13.4 to 42.3 EUR MWh-1 lower) comparing with the standalone waste to energy case. The study shows that: (i) in the integrated case and for the increasing steam parameters energy, economic and ecological performances are improved; (ii) increasing the solar contribution could be an efficient way to improve the process and system performances. In general, we can conclude that concentrated solar-power technology holds significant promise for extending and developing the waste to energy systems.

2020 ◽  
pp. 0958305X2092159
Author(s):  
Umish Srivastva ◽  
K Ravi Kumar ◽  
RK Malhotra ◽  
SC Kaushik

The paper presents energy–exergy–economic–environment–ethics analysis of a concentrated solar thermal power plant. Design basis of a concentrated solar power for 24 h operation on parabolic trough collector technology in best suited direct normal irradiation location and least capital cost analysis has been presented. An unconventional approach of reducing the capital cost is analyzed by intentionally designing the power plant for sub-critical conditions using a low-cost mineral oil with permissible operating temperature of 320°C in place of the conventional synthetic solar grade oil of 400°C. Using low pressure and temperature steam in the plant, it has been shown that while there is a reduction of 0.1% in energetic efficiency, there is a gain of 0.28% in the exergetic efficiency of the solar power plant conditions, gross thermal efficiency decreases by 1.18% and the net thermal efficiency decreases by 2.91%. However, the energetic and exergetic utilization factor for heat transfer fluid is increased by 0.84 and 5.58%, respectively. By suitably adjusting the solar field configuration and inlet oil temperature, energy savings to the tune of 45% is possible apart from 2.5 times of cost saving. An attempt has been made to quantifiably assess the ethics of switching to renewable electricity through shared responsibility as a novelty in the study. The payback period for the investment has also been shown to reduce from 20 years to 5 years assuming that the carbon price increases, concentrated solar power cost comes down by 25%, and cost at which electricity can be sold increases to US $0.14 (Rs. 10) per unit.


Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1063
Author(s):  
Catalina Hernández Moris ◽  
Maria Teresa Cerda Guevara ◽  
Alois Salmon ◽  
Alvaro Lorca

The energy sector in Chile demands a significant increase in renewable energy sources in the near future, and concentrated solar power (CSP) technologies are becoming increasingly competitive as compared to natural gas plants. Motivated by this, this paper presents a comparison between solar technologies such as hybrid plants and natural gas-based thermal technologies, as both technologies share several characteristics that are comparable and beneficial for the power grid. This comparison is made from an economic point of view using the Levelized Cost of Energy (LCOE) metric and in terms of the systemic benefits related to flexibility, which is very much required due to the current decarbonization scenario of Chile’s energy matrix. The results show that the LCOE of the four hybrid plant models studied is lower than the LCOE of the gas plant. A solar hybrid plant configuration composed of a photovoltaic and solar tower plant (STP) with 13 h of storage and without generation restrictions has an LCOE 53 USD/MWh, while the natural gas technology evaluated with an 85% plant factor and a variable fuel cost of 2.0 USD/MMBtu has an LCOE of 86 USD/MWh. Thus, solar hybrid plants under a particular set of conditions are shown to be more cost-effective than their closest competitor for the Chilean grid while still providing significant dispatchability and flexibility.


Author(s):  
Ben Xu ◽  
Peiwen Li ◽  
Cholik Chan

With a large capacity thermal storage system using phase change material (PCM), Concentrated Solar Power (CSP) is a promising technology for high efficiency of solar energy utilization. In a thermal storage system, a dual-media thermal storage tank is typically adopted in industry for the purpose of reducing the use of the heat transfer fluid (HTF). While the dual-media sensible heat storage system has been well studied, a dual-media latent heat storage system (LHSS) still needs more attention and study; particularly, the sizing of volumes of storage tanks considering actual operation conditions is of significance. In this paper, a strategy for LHSS volume sizing is proposed, which is based on computations using an enthalpy-based 1D model. One example of 60MW solar thermal power plant with 35% thermal efficiency is presented. In the study, potassium hydroxide (KOH) is adopted as PCM and Therminol VP-1 is used as HTF. The operational temperatures of the storage system are 390°C and 310°C, respectively for the high and low temperatures. The system is assumed to operate for 100 days with 6 hours charge and 6 hours discharge every day. From the study, the needed height of the thermal storage tank is calculated from using the strategy of tank sizing. The method for tank volume sizing is of significance to engineering application.


Sign in / Sign up

Export Citation Format

Share Document