• Energy Research

AbstractEvaporation cooling systems are currently deployed in the majority of operating Concentrating Solar Power (CSP) plants. However, the fundamental drawback of this approach is that large quantities of water are used in the cooling tower, so that this solution will be not applicable for a large-scale CSP development in arid regions. In fact, in most of the sites suitable for CSP applications, ambient temperatures are typically high and water is scarcely available, or the cost of transporting water to these sites is prohibitive. For this reason, at these sites dry cooling will be the only viable option. This paper analyses the impact of dry cooling systems on technical and economic plant performances, considering several condenser layouts, different operation strategies and economic boundary conditions. In particular, the capacity and the operation of the thermal energy storage can be optimized in order to maximize power production, e.g. by preferential plant commitment at night hours. The analysis is carried out for three selected locations with real meteorological data by means of annual simulations with hourly time steps.

The introduction of Sustainable Aviation Fuel (SAF) is expected to play an important role in the decarbonisation of the aviation sector.

AbstractOne of the major difficulties in the assessment of costs of desalination projects is that key investment parameters and operation-related parameters are project-specific data. This information is commonly not in the public domain and is generally available only to the general contractor. In addition, the interpretation of published data is complicated by the fact that often plant boundaries are not clearly indicated (e.g. if the intake cost and the pipeline cost to and from the plant are included in the evaluation). Finally, the analysis involves an elevate number of design parameters, such as plant capacity and configuration, metal and other material prices, and very site-specific conditions (seawater quality, feed water intake, and brine discharge). In the end, these issues result in difficult comparability of data from different sources about the cost of the desalinated water. This paper deals with the implementation of a flexible techno-economic model for the assessment of desalination plants ...

Abstract The Liquid Solar Fuel (LSF) concept aims to provide renewable-energy-based fuels like synthetic Diesel and Kerosene for long-distance transport via trucks, ships and airplanes and for remote machinery. The purpose of this paper is to present a preliminary design and performance model of a small scale plant with a rated production capacity of 100 barrels per day. First technical and economic performance estimates suggest that an achievable process efficiency around 50% and a product cost of ca. 1 US$/liter for large scale units in the medium term future can be attractive when compared to similar processes like power-to-liquid or biomass-to-liquid. A key attribute of the LSF concept is to maximize efficiency of all physical and chemical processes involved by continuous full-load operation of the synthesis process avoiding any transients, and by integrating and recycling all involved energy and material flows. How to achieve this in an effective way in spite of mainly using variable renewable energy from sunshine and wind for power supply is a key finding of the analysis, significantly reducing the need for major storage facilities for hydrogen and other involved substances. A major implication of the study is that carbon-free production of synthetic liquid hydrocarbon fuels is possible with present state-of-the-art technologies and can be efficient and affordable under appropriate frame conditions that exist in many parts of the world. The analysis has been made in the frame of internal activities of the Department of Systems Analysis and Technology Assessment at the German Aerospace Center (DLR) in Stuttgart, Germany, since 2008, and had the goal to identify sustainable solutions for future long-distance transport fuels. The model analysis provides technical and economic performance estimates of a first prototype.

Synthetic fuels play an important role in the defossilization of future aviation transport. To reduce the ecological impact of remote airports due to the long-range transportation of kerosene, decentralized on-site production of synthetic paraffinic kerosene is applicable, preferably as a near-drop-in fuel or, alternatively, as a blend. One possible solution for such a production of synthetic kerosene is the power-to-liquid process. We describe the basic development of a simplified plant layout addressing the specific challenges of decentralized kerosene production that differs from most of the current approaches for infrastructural well-connected regions. The decisive influence of the Fischer–Tropsch synthesis on the power-to-liquid (PtL) process is shown by means of a steady-state reactor model, which was developed in Python and serves as a basis for the further development of a modular environment able to represent entire process chains. The reactor model is based on reaction kinetics according to the current literature. The effects of adjustments of the main operation parameters on the reactor behavior were evaluated, and the impacts on the up- and downstream processes are described. The results prove the governing influence of the Fischer–Tropsch reactor on the PtL process and show its flexibility regarding the desired product fraction output, which makes it an appropriate solution for decentralized kerosene production.

DLR developed the optimization model REMix-CEM (Renewable Energy Mix - Capacity Expansion Model). REMix CEM to generate a cost-effective expansion planning of thermal and renewable assets with respect to a use optimization (dispatch) of various types of power plants for the energy system. Working closely with the Moroccan Ministry of Energy energy scenarios are created to support Morocco in the medium to long-term energy planning to develop cost-effective, and technically feasible expansion plans for renewable energy and better coordinate the interaction between different forms of electricity generation.