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In 100% renewable energy systems, the requirements for flexibility will be greater than for traditional carbon-based energy systems. New technologies and system setups are needed to provide flexibility for balancing the system. Implementing electricity storages in the energy system could provide parts of the required flexible demand and production, though most of these storage solutions have been shown to have relatively high costs. So-called Carnot batteries have been shown to have a relatively lower cost than traditional batteries, but at a reduced electric efficiency. This paper investigates to what extent large-scale integration of Carnot batteries has a role in the transition to and the operation of 100% renewable energy systems. By implementing Carnot batteries in a 100% renewable energy scenario for Denmark, the energy system effects are identified. The results indicate that the potential economic benefit could be as high as 60.5–66.2 EUR/MWh e discharged, not including costs related to investment as well as operation and maintenance of the Carnot batteries. Thus, large-scale integration of Carnot batteries must perform below this economic threshold to be economic relevant. Existing concepts for stand-alone Carnot batteries are not able to achieve these costs today, therefore solutions for cost reductions should be investigated. • Electricity storages could provide parts of future required system flexibility. • Most of these storage solutions have been shown to have relatively high costs. • Carnot batteries have a relatively lower costs but at reduced electric efficiency. • Large-scale integration of Carnot batteries is tested in a renewable energy system. • Carnot battery concepts should aim for a cost lower than 60.5–66.2 EUR/MWh e. [ABSTRACT FROM AUTHOR]

Some benefits of spot electricity markets integration include the optimization of renewable power, increasing transmission grid security and the decreasing need for internal generation reserves. The high penetration of wind power is known to have a clear influence on price convergence between electricity markets joined by market splitting. However, in multiple interconnected markets, cross-border flows can also play a role in the market splitting behaviour. Denmark, with a high penetration of wind power, is clearly the ideal case study. This paper aims to assess the influence of high penetration of wind power on the market splitting behaviour between West and East Denmark, taking into account cross-border electricity flows. This is modelled through logit and non-parametric models, estimating the probability of market splitting occurrence between both Danish bidding areas. Market splitting probability is found to be sensitive to wind power, nevertheless with distinct behaviour according to interconnection congestion configuration. The highest availability of wind power in West Denmark, which can reach a generation share of 1.5 times the demand, requires strong cross-border interconnections to allow the export of the excess generation. Policies governing a joint assessment of the requirements for additional interconnection and wind power expansion plans, should be developed. [ABSTRACT FROM AUTHOR]

Abstract: Denmark’s long-term energy goal is to develop an energy system solely based on renewable energy sources by 2050. To reach this goal, energy savings in buildings is essential. Therefore, the focus on energy efficient measures in buildings and net zero energy buildings (NZEBs) has increased. Most buildings in Denmark are connected to electricity grids and around half are connected to district heating (DH) systems. Connecting buildings to larger energy systems enables them to send and receive energy from these systems. This paper’s objective is to examine how excess heat production from NZEBs influences different types of DH systems. In the analysis three different types of DH systems are analyzed, and three technology development scenarios for each are created. The examination is from a technical perspective and looks into how the overall heat production within DH areas is affected by the NZEBs excess heat production from solar thermal collectors. The main findings are that the excess heat from NZEBs can benefit DH systems by decreasing the production from production units utilizing combustible fuels. In DH areas where the heat demand in summer months is already covered by renewable energy, adding seasonal heat storage is essential to utilize the NZEB production. [Copyright &y& Elsevier]