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District heating is a network of pipes through which heat is delivered from a centralised source. It is expected to play an important role in the decarbonisation of the energy sector in the coming years. In district heating, heat is traditionally generated through fossil fuels, often with combined heat and power (CHP) units. However, increasingly, waste heat is being used as a low carbon alternative, either directly or, for low temperature sources, via a heat pump. The design of district heating often has competing objectives: the need for inexpensive energy and meeting low carbon targets. In addition, the planning of district heating schemes is subject to multiple sources of uncertainty such as variability in heat demand and energy prices. This paper proposes a decision support tool to analyse and compare system designs for district heating under uncertainty using stochastic ordering (dominance). Contrary to traditional uncertainty metrics that provide statistical summaries and impose total ordering, stochastic ordering is a partial ordering and operates with full probability distributions. In our analysis, we apply the orderings in the mean and dispersion to the waste heat recovery problem in Brunswick, Germany.

Abstract Important aspects of electricity system planning are overall yearly electricity consumption and information about variations in consumption. These variations will influence the capacity that has to be installed, as well as the type and quantity of fuel that will be used. Using only economic, socio-economic, technical and meteorological indicators, we have developed a model that can predict the hourly load shape. This model is based on a division of the total electricity-consumption into 60 economic sectors and electrical appliances. For each of these sectors, a load shape is formed. Summation over sectors then gives the total hourly electricity consumption pattern. To test this model, the hour-to-hour load shape of the Dutch public grid for 1980 was formulated and compared with the actual load shape. The root-mean-square difference between the estimated and actual load shapes is 5% of the mean hourly load. The accuracy of the estimated maximum load for every week is of the same magnitude as that used for electricity-supply system planning over the short term. We conclude that our model can be used for long-term load shape forecasting.

Heating and cooling using aquifer thermal energy storage (ATES) has hardly been applied outside the Netherlands, even though it could make a valuable contribution to the energy transition. The Climate-KIC project "Europe-wide Use of Energy from aquifers" - E-USE(aq) - aimed to pave the way for Europe-wide application of ATES, through the realization and monitoring of six ATES pilot plants across five different EU countries. In a preceding paper, based on preliminary results of E-USE(aq), conclusions were already drawn, demonstrating how the barriers for this form of shallow geothermal energy can be overcome, and sometimes even leveraged as opportunities. Based on final pilot project results, key economic and environmental outcomes are now presented. This paper starts with the analysis of specific technological barriers: unfamiliarity with the subsurface, presumed limited compatibility with existing energy provision systems (especially district heating), energy imbalances and groundwater contamination. The paper then shows how these barriers have been tackled, using improved site investigation and monitoring technologies to map heterogeneous subsoils. In this way ATES can cost-efficiently be included in smart grids and combined with other sources of renewable (especially solar) energy, while at the same time achieving groundwater remediation. A comparative assessment of economic and environmental impacts of the pilots is included, to demonstrate the sustainability of ATES system with different renewables and renewable-based technologies. The paper concludes with an assessment of the market application potential of ATES, including in areas with water scarcity, and a review of climate beneficial impact.

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We consider the problem of dispatching a fleet of distributed energy reserve devices to collectively meet a sequence of power requests over time. Under the restriction that reserves cannot be replenished, we aim to maximise the survival time of an energy-constrained islanded electrical system; and we discuss realistic scenarios in which this might be the ultimate goal of the grid operator. We present a policy that achieves this optimality, and generalise this into a set-theoretic result that implies there is no better policy available, regardless of the realised energy requirement scenario. Accepted for publication to the 2018 Power Systems Computation Conference (PSCC)

UNAFLOW(UNsteady Aerodynamics for FloatingWind) is a joint EU-IRPWIND founded experiment on wind turbine rotor unsteady aerodynamics. It brings together four different academic contributors: Energy research Centre of the Netherlands (ECN), DTU Wind Energy, University of Stuttgart (USTUTT) and Politecnico di Milano (PoliMi) sharing knowledge both in numerical modelling and in experimental tests design, allowing direct numerical and experimental comparison. The experimental tests carried out for UNAFLOW are of the same type of the ones carried out during the ongoing EU H2020 project LIFES50+ [1], regarding both the unsteady behaviour of the 2d blade section and the entire turbine rotor, although with improved setup and wider test matrix. The project partners are already currently jointly collaborating in the AVATAR project [2], developing and validating numerical models of different accuracy level. The numerical models used in the UNALFOW project range from engineering tool (eg. BEM) to high fidelity CFD methods. Numerical simulations are used both in the design of experiment phase and in the results analysis allowing for an in depth understanding of the experimental findings through advanced modelling approach. The UNAFLOW project, together with a new understanding of the unsteady behaviour of the turbine rotor aerodynamics, will provide also an open database to be shared among the scientific community for future analysis and new models validation.

Population growth, increasing energy demand and the depletion of fossil fuel reserves necessitate a search for sustainable alternatives for electricity generation. Hydropower could replace a large part of the contribution of gas and oil to the present energy mix. However, previous high-resolution estimates of hydropower potential have been local, and have yet to be applied on a global scale. This study is the first to formally present a detailed evaluation of the hydropower potential of each location, based on slope and discharge of each river in the world. The gross theoretical hydropower potential is approximately 52 PWh/year divided over 11.8 million locations. This 52 PWh/year is equal to 33% of the annually required energy, while the present energy production by hydropower plants is just 3% of the annually required energy. The results of this study: all potentially interesting locations for hydroelectric power plants, are available online.