The Storage of Sustainable Energy in the Built environment Exploratory research on increasing sustainability using Smart Grids

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TVVL, Platform for People and Technology, requested Royal Haskoning to investigate the subject of Energy storage and smart grids. Primary and secondary research questions were formulated jointly with TVVL, and then subsequently answered during the exploratory research. The primary issue is as follows:


Taking account of the solutions offered by smart grids, how desirable is the storage of energy at the domestic housing, building or district levels in both the short and long term, and which types of storage methods are the most feasible?


Several secondary questions were formulated to help answer the primary question. The secondary questions and their answers are handled below.

Secondary question 1: To what extent is there a need for the storage of electrical energy in the built environment, now and in the future?: The need for the storage of (sustainable) electrical energy in the built environment is quite low at present. In future the need for storage in the built environment will largely arise from the need for decentralised producers to be able to trade more effectively. Therefore the consumer/decentral producer with a storage medium will be able to charge up when electricity prices are low and discharge when they are high. Peak - valley compensation, supply and quality optimisation, and peak shaving are of minor importance at the level of the built environment. In addition it can be expected that policy at European and national levels will contribute to more development and use of decentralised electricity generation, which will consequently be an important driver for storage media in the built environment. Also trends such as multifunctional use of land, electrification, scale reduction and the trend towards the smart division of decentralised electricity production will provide stimulation, encourage the potential development and speed up the implementation of the storage of electrical energy. However, contrary to these developments that benefit the use of storage on a smaller-scale, the costs of realising large-scale flexibility are relatively low.


Secondary question 2: Which methods of electrical energy storage could be considered at the building and district levels?: Batteries and hydrogen are the storage methods with most potential when viewed from the perspectives of technical selection criteria, power discharge time, response time and energy capacity. Due to its extensive storage cycle hydrogen has the most disadvantages and its small-scale use will be complex. In the short term the system that is most suitable for the storage of electrical energy in the built environment is the battery. Batteries combine good energy density (stored energy per kilogram and stored energy per volume) with efficiency (small losses during the charging and discharging cycles). Large storage capacities using batteries are currently uneconomical due to the high costs of storage capacity (€/kWh). Battery systems are suitable for bridging the day/night cycle, but not for the seasonal cycle. Also battery-based systems can assist with the efficient use of energy by buffering between supply and demand. Extensive development is taking place in the field of battery technology. Lithium-sulphur and lithium-air batteries in particular appear to have considerable future potential.


Secondary question 3: To what extent is there an inhibiting or a facilitating link between the use of smart grids and the use of electrical energy in the built environment?  Imbalance between local generation and local consumption in the smart grid can be compensated by local solutions (storage or control of demand) or it can be left to higher-level networks. Aggregating at a higher level of imbalance can reduce the total risk of imbalance. This does involve costs for transmission and control power. Smart grids make this local balancing with the help of local storage technically possible and could thus be a stimulus. On the other hand because the smart grid is also linked to higher-level networks it makes the balancing possible at a higher level. The opposite also applies, as any potential imbalance at higher levels could be taken up by local smart grids.


Considering the stage of development of the current grid, its high operational reliability and the potential added value of information and communication technology, it is likely that in the short term most solutions will be found by further optimisation of the existing grid system into a smart grid. This does not mean that storage will not be used. When storage techniques have been further developed they will be a welcome extension of the smart grid concept, enabling practical applications that will primarily depend on the cost effectiveness of two scenarios: a rise in the use of storage and/or a rise in the amount of power being fed back into the grid. Due to the stage of development of smart grids, with the opportunities for feed-in and the lack of storage capacity, it is likely that in the short term increased feed-in will develop. Over the longer term the storage scenario will continue to develop and both could exist alongside each other.


Secondary question 4: What is the state of the playing field for the stakeholders in smart grids and electrical energy storage and what consequences does this have for the feasibility of the storage of electrical energy in the built environment?

What is the state of the playing field? Many stakeholders are involved with smart grids and the storage of energy. To some degree or another they all have an interest in the development of smart grids and any potential storage facilities within them. The playing field is characterised by the stakeholders involved having partly conflicting interests and goals. For example the traditional central producer who is not going to benefit from decentralised production, or the supplier who will benefit from smart grids (more trade) but will not benefit from decentralised storage. At the moment there appears to be no likelihood of fruitful cooperation or useful alignment of interests and goals.


What consequence does this have for the feasibility of the storage of electrical energy in the built environment? The current electricity grid (and certainly with the expected smart grid modifications) does not need decentralised storage for the power supply system in the Netherlands. Therefore it cannot be expected that mandatory policies and regulations governing storage will be introduced. However, one reason to go for storage could be economic. The cost effectiveness for the various stakeholders will therefore be a deciding factor. If decentralised storage does make progress then it is likely that the first party for whom storage becomes profitable will be the consumer/decentralised producer. A consequence is that shared (organised) storage will not take place for the time being for the ‘playing field’. It is most likely that one party will start on its own.


In the context of a number of sketched future scenarios it is probable that storage will go ahead, in the first instance the individualism scenario is likely to be at the forefront. Storage offers economies of scale, therefore when the smart grid, including storage, is further optimised, it can be expected that shared storage will eventually take place. Therefore we forecast a scenario such as Delayed Moderate Collectivism.

Energy storage, decentralised energy generation and smart grids are multi-faceted subjects offering a great deal of scope for research. To anyone who starts working in the field it soon becomes even clearer. It is not surprising that there are professors specialising in smart grids. The term ‘smart grid’ is sometimes considered to be a buzz-word or a hyped-up subject. It is an umbrella term for something that is difficult to define and as with every innovation or transition there is a lot involved. This is a subject of great interest to both Royal Haskoning and TVVL. Not to mention the subject ‘The storage of (sustainably generated) electricity in the built environment’, which forms just a part of this comprehensive and complex issue? Nevertheless we are of the opinion that in this report the correct questions have been asked and answered. But at the same time this report does nothing to reduce the complexity of this extensive subject.