Zukünftige Energie- und Industriesysteme
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(2012)
Technical summary
(2015)
At current primary steel production levels, the iron and steel industry will fail to meet the 80% emission reduction target without introduction of breakthrough technologies (Wörtler et al., 2013: 19). The current research analyses the technical and economical long-term potential of innovative primary steel production technologies in Germany throughout 2100. Techno-economic models are used to simulate three innovative ore-based steelmaking routes verses the reference blast furnace route (BF-BOF). The innovative routes in focus are blast furnace with CCS (BF-CCS), hydrogen direct reduction (H-DR), and iron ore electrolysis (EW). Energy and mass flows for the production of one tonne of crude steel (CS) are combined with hypothetical price, cost, and revenue data to evaluate the production routes economically, technically, and environmentally. This is a purely theoretical analysis and hence further external factors that may influence practical implementation or profitability are not considered.
Different future developments are considered by using three scenarios, representing an ambitious, a moderate, and a conservative transformation of the German energy sector. In general, looking into the future bares various uncertainties which should be reflected in a suitable manner.
According to the present scenario analysis, chances are that with rising prices for coal and CO2 allowances BF-BOF and even BF-CCS become unprofitable by mid-century. With a high share of renewable energy sources and high prices for CO2 allowances, H-DR and EW become economically attractive in the second half of the current century, when BF-based routes are long unprofitable. Energy and raw material efficiency is significantly higher for H-DR and EW and furthermore, the 80% reduction target by 2050 can be achieved in the ambitious scenario. However, high investment costs and high dependency on electricity prices prohibit a profitable implementation before 2030–2040 without further subsidies. EW is the most energy and resource efficient production route. Since continuous electricity is needed for the continuous operation, the electricity costs are 20–40% higher than for H-DR (with high-capacity hydrogen storage units). Even though hydrogen production implies efficiency losses compared to the EW route, the decoupling of hydrogen production from continuous operation of the steel plant through hydrogen storage offers the opportunity to use cheap excess renewable electricity. This makes the H-DR economically and environmentally the most attractive route and provides a crucial contribution to stabilize the grid and to store excess energy in a 100% renewable energy system.
Techno-economic feasibility study of solar and wind based irrigation systems in Northern Colombia
(2014)
Water pumping systems powered by solar and wind energy are a clean, decentralized and economic alternative for the irrigation of crops. The intense droughts experienced in the last years in Northern Colombia due to particularly strong Nino Phenomena have reactivated the need of reliable water pumping irrigation systems in that region. This study aims to assess the techno economic feasibility of solar and wind based pumping irrigation system, taking as case study the Municipality of Piojo in the Atlantico department. In the first stage of the study the irrigation water requirements were determined by using the software CROPWAT based on two different crop patterns that represent existing feasible alternatives for small farmers of the region: i) a common crop pattern, which represent the current average distribution of crops for subsistence farming and ii) a fruit cash crop pattern that comprises crops for which well established markets in the region exist. Solar wind and diesel based pumping systems were sized based on the crop water demands for 1 ha. The unit irrigation costs of the three technologies, the two crop patterns and the three irrigation methods (surface, sprinkler and drip) were calculated and compared. The economical analysis was complemented with a cost-benefit analysis over 20 years. Our results show that both renewable energy based pumping systems (wind and solar) can cover the irrigation water demands of small farmers in the region. The economical analysis shows that windmills are the most cost effective solution followed by the solar pumping system. Diesel pumping system was the less cost effective, even though it does not comprise investment in water storage tank. The cost benefit analysis demonstrates that any irrigation system is financially unfeasible when providing water to a common crop pattern. In case of the fruit cash crop scenario the highest dividends were obtained by the wind pumping system and the lowest dividends by the diesel pumping system. The lowest payback period was obtained by the windmill after 7 years and could be even feasible after the fifth year if the surplus water would be used to irrigate larger areas. Dividends obtained in a fruit cash crop scenario with irrigation after 20 years were in the range of EUR 5200 and EUR 11200 higher than dividends obtained by the same crop pattern but without irrigation.
Eine zukünftige Herausforderung der Energiewende wird darin bestehen, zunehmende Stromnetzeinspeisungen von fluktuierenden erneuerbaren Energien (FEE) in das Energiesystem zu integrieren. Neben den Flexibilitäten im Stromsystem sollten dabei auch die Möglichkeiten des Wärmemarktes zur Stabilisierung des Strommarktes berücksichtigt werden. So können Kraft-Wärme-Kopplungs-Anlagen (KWK), Elektroheizer und Wärmepumpen als Verbindungstechnologien zwischen Strom- und Wärmemarkt abhängig vom FEE-Dargebot und damit auch den Preissignalen des Strommarktes zu- bzw. abgeschaltet werden. Dazu werden Wärmespeicher benötigt, da die Flexibilisierung nur möglich ist, wenn die Produktion von der Wärmenutzung entkoppelt werden kann. Eine besonders aussichtsreiche Kopplung von Strom- und Wärmemarkt ist im Bereich der Fernwärmesysteme möglich, da sich hier große Energiemengen in Fernwärmespeichern im Vergleich zu dezentralen Lösungen kostengünstiger und effizienter speichern lassen.