Current developments in the renewable energy field, and the trend toward self-production and self-consumption of energy, has led to increased interest in the means of storing electrical energy; a key element of sustainable development.
This book provides an in-depth view of the environmentally responsible energy solutions currently available for use in the building sector. It highlights the importance of storing electrical energy, demonstrates the many services that the storage of electrical energy can bring, and discusses the important socio-economic factors related to the emergence of smart buildings and smart grids. Finally, it presents the methodological tools needed to build a system of storage-based energy management, illustrated by concrete, pedagogic examples.
In France, in 2016, residential and tertiary sector buildings represented 45% of total final energy use. The proportion of electrical energy continues to increase, currently representing approximately 37% [MIN 17]. There is thus much to be gained by increasing energy efficiency in this area, equipping buildings to produce and store energy and establishing intelligent energy management systems, interacting with the distribution grid.
Current developments in the sphere of renewable energy and the trend toward self-production and self-consumption of electrical energy produced onsite have led to increased interest in the means of storing electrical energy, a key element of sustainable development. Self-consumption provides a stimulus for better mastery of energy consumption and leads to a reduction in electric bills (reducing costs associated with connection to the main distribution grid, subscribed power and, potentially, taxes). Collective self-consumption can result in additional optimizations, grouping together buildings with different consumption profiles in terms of time. Considerable gains may also be made through load management, modulating consumption by adjusting loads or through local production and self-consumption, with or without a storage system. Finally, in addition to these financial aspects, collectives may benefit from using renewable forms of self-consumption (one of the main aims in such cases), as there are several potential sources of production (notably solar panels on roofs). The consumption of locally produced energy also prevents or limits losses associated with the transportation of energy over long distances.
The increase in popularity of electricity as an energy carrier for buildings can be attributed to the flexibility which it offers, as well as to the potential to avoid pollution at the usage site. In the coming years, an increasing proportion of these buildings will be equipped with storage systems, providing emergency backup, compensating for natural variations in renewable energy supplies, and will also be able to provide services for the wider electric system. Storage systems are expensive, and shared usage offers a means of spreading the cost, while contributing to the management of system aging. At the time of writing, studies are being carried out with regard to using the storage capacity of electric vehicles to provide services to the electric distribution grid or to the buildings where they recharge: these solutions are known as Vehicle to Grid (V2G) and Vehicle to Home (V2H). Similar solutions would be possible for integrated storage in commercial and tertiary (with offices) buildings, or, indeed, whole residential neighborhoods.
The aim of this book is to increase awareness of the potential offered by these developing technologies, in the context of buildings, groups of buildings and/or neighborhoods, integrated into large "smart grids" or forming smaller "micro grids", particularly with regard to their management and valorization.
Storage will form an essential element of future smart grids, but these networks will be unable to attain their full "smart" potential without collecting large amounts of data, via connected meters, among other things. The installation of these meters raises ethical questions with regard to the protection of the data which they generate, which should give a precise indication of the energy usage habits of consumers, but is also affected by questions of cybersecurity.
The development of self-consumption of locally produced energy raises other ethical questions of a fundamental nature: energy, particularly electricity, has become essential to maintaining the lifestyles of industrialized societies, for comfort, sanitation, security, education and more. Self-consumption challenges the current electrical supply model, which is highly centralized in terms of both production and management. We are effectively facing an energy revolution. In extreme cases of self-consumption, in which public network management entities are left out of the picture altogether, this could be compared to the "uberization" (an exchange of services between private individuals to the exclusion of larger companies, enabled through the use of Internet applications) recently seen in the contexts of urban automobile transport and short-term lets. However, access to electricity is essential to the operation of our societies, which are highly dependent on this energy supply. Self-consumption could also undermine the French principles of energy solidarity and equal access to energy (in terms of cost). These last points raise further ethical questions, particularly with regard to an increased risk of energy poverty and even energy-based communitarianism. There is a danger that self-consumption may simply benefit those consumers who are already in a strong position - for example wealthier households with the financial capacity to install solar panels on the roofs of their houses.
Furthermore, self-consumption is largely based on the use of "new" renewable energy sources (essentially solar, as well as wind power), which are, by their very nature, variable and weather-dependent, fluctuating significantly with the seasons and from day to night. This being so, climate change is a source of additional uncertainty with regard to the future behavior of these new technological solutions.
For these reasons, we would do well to adopt an ethical rule set out in [GIO 18]: "Do not leave your children to solve problems which you yourself voluntarily created, which are of vital importance for your descendants, and for which you are not sure that a realistic solution exists or will be found in the future. Furthermore, any advances resulting from the scientific discoveries and/or technological developments in question should support the common good and promote the restoration of original ecosystems, if these systems created balance and harmony, wherever possible".
This does not mean that we should limit research into the development of smart grids and self-consumption; instead, these projects should be subject to regular ethical review in connection with the questions set out above (even though the risks seem smaller and of a different nature to those associated with the development of nuclear power). An interdisciplinary approach to these questions is necessary, connecting science and sociology, economics, ethics and even, where applicable, legal considerations. Law-makers have a key part to play in providing an "ethical buttress" [GIO 18] for new methods of energy production and consumption.
In Europe, Germany leads the way in terms of electrical self-consumption, with 500,000 installations in 2018, compared to 20,000 in France, where a regulatory framework has yet to be fully defined. Debate centers on the notion of locality as it relates to self-consumption, a notion that may be defined in various ways. It may be limited to part of the distribution grid (e.g. downstream of a medium-voltage to low-voltage transformer substation [CRE 18] serving part of a residential neighborhood) or to a distance, for example a one-kilometer radius around a production facility [MIN 18] enabling energy exchanges between large-scale service buildings in addition to homes. There are also questions regarding taxation: for example, in France, a tax is levied to support the development of renewable energy, and self-supply installations of under 9 kW [CRE 18] or 1 MW [MIN 18] may be exonerated. Finally, the charges for use of the public distribution grid by collective self-consumption, which only use a small portion of this network, need to be determined; these entities must remain connected to the grid to ensure that supply is maintained even though their renewable systems are not producing electricity and there is no power stored on-site.
The aims of this book are:
- - to highlight the importance of storing electrical energy in the context of sustainable development, smart buildings, smart grids and smart cities;
- - to demonstrate the variety of services which electrical energy storage may provide;
- - to consider the socio-economic questions associated with changes stemming from the emergence of smart buildings and smart grids, providing elements of response;
- - to present methodological tools for the design of a management system for stored energy, following a generic and pedagogical approach. These tools are based on causal approach, artificial intelligence and explicit optimization techniques. They will be presented throughout the book, in the context of real-world case studies;
- - to illustrate these methodological approaches through the use of various real-world examples, used as a basis for clearly explaining the integration of renewable energy and electric vehicles into our environment (buildings, energy sharing between residential and tertiary buildings, urban neighborhoods and rail energy hubs).
In Chapter 1, we will describe the issues surrounding electrical energy storage in buildings, blocks and neighborhoods, whether integrated into a large smart grid or forming their own micro grid. We will highlight the storage requirements for these applications, alongside the services which they may provide. The socio-economic aspects of these developments will be touched on briefly; a more detailed discussion of these elements is provided in Chapter 5. We will also introduce a methodology for designing a management system for energy storage systems. This system is particularly suitable for the management of complex systems, featuring elements of uncertainty...