Hire fast, fire slow: the employment benefits of energy transitions

The transition towards decarbonized and efficient energy systems has broad socio-economic implications. We estimate the potential impacts on employment from efforts in energy efficiency in industry, transport and buildings as well as substituting local renewable energy sources for fossil fuels. Both energy supply and demand are accounted for. We use a hybrid approach that combines national energy transition scenarios with input–output tables, adjusted for new energy and non-energy activities. We conclude that the transition has a net positive impact on employment as illustrated by the case of Switzerland. The local and decentralized nature of energy efficiency and renewables retains a greater share of value-added domestically than does a supply chain of fossil fuels. Moreover, we find that more jobs are created in demand-side activities, such as building renovation, than in renewable energy generation. Positive impacts on jobs from spillover effects in all non-energy activities are also found.

Experimental investigation of electrical domestic heat pumps equipped with a twin-stage oil-free radial compressor

Jean-Baptiste Carré

The world energy consumption has dramatically increased since the end of the World War II. The main share of this energy comes from fossil fuel combustion. The worldwide domestic sector consumes about 30% of the global energy supply and the biggest share of that is dedicated to space and water heating. In this context where sustainable energy consumption is required to limit our impact on the environment and the climate, energy efficiency is a key factor to successfully transition to energy sobriety. Electrically-driven heat pumps are known to be a key technology to increase our energy efficiency. More efficient, more compact, more silent heat pumps, built with less raw material, and using lower refrigerant charges are needed. In electrically-driven heat pumps, the compression process is responsible for most of the energy losses. However, for decades now, the heat pump performance has been stagnating, mainly because of the compression process efficiency which has not been increasing significantly. Consequently, the improvement of the compression process is indeed needed. A new single-stage compression unit design has been developed, built, and tested in a previous thesis work. This current thesis work uses a twin-stage successor of the initial single-stage compression unit and tests it into two oil-free domestic heat pump prototypes. This work aims at studying the integration of the radial compression units in domestic heat pumps and at demonstrating their feasibility and potential. The tested prototypes are a twin-stage Air/Water domestic heat pump and a twin-stage Brine/Water domestic heat pump. Both of them are equipped with a twin-stage oil-free radial compression unit rotating on gas bearings. By which, the maximum rotor speed of the compression units is 180 krpm. Six stable operating points have been documented with the Air/Water heat pump prototype. More notably so, the operating point A-7/W35 has been reached and demonstrates a coefficient of performance of 2.36 for a heating power of 10.7 kW. The Brine/Water heat pump prototype has been used to perform partial tests of circuit improvements, in order to solve some of the issues observed on the Air/Water prototype. The analysis of the experimental results uses a mass and energy balance modeling approach to improve the level of understanding of the internal and non measurable flows in the heat pump circuits. This model also propagates the uncertainties of the measurements through the equations. New improvements and innovative circuit layouts, notably at the level of the economizer, a key-component of the two-stage heat pump circuit, are offered to integrate further the compression unit in the heat pump circuits, and to make the whole system more efficient, more compact, more silent, less demanding in raw materials and reducing the refrigerant charge needed for the heat pump cycle.

EPFL2015

Rusty dinosaurs and the surviving species in the new energy system? Analysing urban utilities in the German and Swiss energy transition

Claudia Rebeca Binder Signer, Susan Marie Mühlemeier

After the nuclear accident in Fukushima, amongst others Germany and Switzerland decided to accelerate the sustainability transition of their energy systems not only by expanding the share of renewables actively but also by quitting nuclear power. Regarding this political level of ambition, energy companies´ strategies play a decisive role in terms of the implementation, progress and success of the energy supply system’s transition. So far scholars in sustainability transition research working on the role of energy companies for the transition process, mainly focused on two actor types: firstly, big energy utilities, the incumbents which often hinder the transition and secondly, the new entrants, small innovative businesses challenging the incumbents with new technologies or business models. However, hardly any scholarly work studies another important actor group, which lies in between: the municipal utilities (“Stadtwerke”). In Germany and Switzerland, some big municipal utilities are part of the ten most powerful energy providers and in Germany they are even seen as the fifth big power besides the “big four”. Hence, the municipal utilities form an important and powerful actor group in terms of the energy transitions’ progress, which need to be studied more in detail. In our work, we analyse i) the structural characteristics of four big municipal utilities in Germany and Switzerland, ii) their business strategies regarding the increase of renewables, iii) how these strategies are influenced by factors from the economic, socio-political and physical environment and iv) how the utilities strategically react to the various influence factors on different scales. We employ the triple embeddedness framework (TEF) by Frank Geels, which considers the interaction of firms with their economic and socio-political environment and facilitates an in-depth case study analysis. For empirical evidence, we conduct an explorative case study analysis with four big municipal utilities in Germany and Switzerland in the cities of Munich, Hannover, Geneva and Zurich. This allows not only for an in-depth analysis of the single municipal utilities, its business strategies and local environment but also for an inter-national comparison of different political settings, which are highly important for the municipal utilities. Methodologically, we firstly employ a document analysis on the utilities structural characteristics and business strategies – on the general firm level but also on the specific business area of renewables. Secondly, we conduct explorative expert interviews with researchers and members of associations in the field as well as the CEOs of the four selected utilities to further reveal the specifics of municipal utilities, obtain an improved knowledge on their business strategies and an overview on important influence factors. Thirdly, we conduct semi-structured expert interviews with different members of the four utilities’ strategic management board, the municipal supervisory board and the renewables department in order to validate and discuss the revealed results and analyse the causal interrelations between the influence factors and the utilities’ strategies. These empirical results will be mirrored with findings from scholarly and practical literature. Preliminarily, our studies show that the four chosen cases are the biggest and oldest municipal utilities in each country, established in the end of the 19th century and they are still mainly in the possession of the cities (min. 75%). The legal form of the utilities varies from being a dependent division of the municipal administration, an independent public enterprise, a private company with limited liability or a corporation. Therewith, the influence from the municipal supervisory board and the room for manoeuvre of the firm varies enormously. Regarding the business areas there is less variation, since all utilities offer a broad range of products in electricity, heat, water and energy consulting. In the area of business strategies, the targets for and the investment in renewables as well as the resources in use are again very divers: some have clear targets to become 100% renewable, others 100% Co2 neutral or there is no such target at all; Zurich and Munich invest intensively in renewables all over Europe whereas Geneva and Hannover focus on the regional and national level. Finally, our first analysis show, that the different relations to their communes and the national laws depict one important set of formal influence factors. In this merely political context, the market liberalisation also plays a fundamental role, since the municipal utilities have to compete in the liberalised energy supply market - since 1998 in Germany, and in Switzerland partly since 2009. As all other energy utilities, the municipal utilities struggle with the multiple uncertainties in the energy supply system, but additionally to the international competition, the municipal actors also need to fulfil their obligations as public service provider for their local urban system. These preliminary results show already, that municipal utilities are important and complex actors with very specific characteristics embedded in multi-scalar environments full of suspense. With our study, we contribute to a better understanding of this actor type, the important context factors and the utilities’ strategic answers in the context of the energy transition. By revealing the specifics in an international comparison, we enrich not only to the scholarly discussion on key actors in the sustainability transition of urban energy supply systems but also provides decision-makers in policy and economy valuable insights for the future design of sustainable and resilient energy governance systems.

2017

Optimal path to a high share of distributed PV in low-voltage distribution grids

Lionel Benjamin Bloch

To limit global warming, the energy transition from fossil fuels to renewables is one of the main challenges of this century. This transition will help decrease our CO2 emissions, create jobs, contribute to a broader revenues distribution, improve energy system efficiency, bring electricity to developing countries and contribute to improving water quality, health care and education. It is made possible thanks to the steady decline of renewable energy costs in particular for photovoltaics (PV) whose electricity cost has decreased by a factor 5 during the last decade. This technology is now cost-effective at different scales of deployment, from GW size power plants to a few kW rooftop systems for prosumers. In Switzerland, due to the free land scarcity, distributed PV systems is one the pillar of the energy transition. However, low-voltage distribution networks were built with centralized generation in mind and were therefore not designed to accommodate a high level of distributed generation. The grid operation requires to maintain, at all time, a balance between consumption and production. An excess of PV energy could require significant curtailment of the generation to cope with the network operating constraints. This technical challenge affects PV system profitability and adoption rate, which is critical to achieving objectives in terms of PV capacity. Moreover, current electricity tariff does not guarantee sustainable revenue for grid operation in the event of an increase in distributed generation and raises issues of equity between consumers and prosumers. Demand-side management can be used to limit PV injection peaks and to reduce the mismatch between production and consumption. By disaggregating households electricity load profiles into appliance categories, we can quantify the share of flexible loads. The electricity consumption flexibility from the behavioural change could have the potential to increase by 20% the PV hosting of a distribution grid. This measure by itself is not sufficient to achieve high PV penetration but should be considered together with technical measures such as PV curtailment or distributed storage. The current typical flat tariff does not take advantage of the flexibility that could be provided by these two measures. To harvest this flexibility, novel electricity pricing mechanisms are presented in this thesis, and their economic and operational performances are assessed using a combination of design and operation optimization, and power flow simulation. We show that unlike time-of-use tariffs which tend to increase the stress on the grid, capacity-based and block rate tariffs reduce the grid usage while ensuring low levelized cost of electricity for prosumers. To fully comply with the grid constraints, an operation regulation could be introduced, but this would lead to a less efficient system with high additional costs. However, a moderate feed-in limit is an efficient solution to reduce peak load on the transformer with only a little impact on system profitability. We finally present a possible path, from 2020 to 2050, toward high PV hosting in a low voltage grid, ensuring at the same time a safe grid operation without grid reinforcement thanks to a progressive feed-in limit, high profitability for the prosumers and constant revenues for grid operation and maintenance. This thesis ends on recommendations for distribution system operators to better anticipate and become part of the energy transition.

EPFL2020