Self-consumption Of Electricity Research Articles

Social and Economic Value in Emerging Decentralized Energy Business Models: A Critical Review

In recent years, numerous studies have explored the opportunities and challenges for emerging decentralized energy systems and business models. However, few studies have focussed specifically on the economic and social value associated with three emerging models: peer-to-peer energy trading (P2P), community self-consumption (CSC) and transactive energy (TE). This article presents the findings of a systematic literature review to address this gap. The paper makes two main contributions to the literature. Firstly, it offers a synthesis of research on the social and economic value of P2P, CSC and TE systems, concluding that there is evidence for a variety of sources of social value (including energy independence, local benefits, social relationships, environmental responsibility and participation and purpose) and economic value (including via self-consumption of renewable electricity, reduced electricity import costs, and improved electricity export prices). Secondly, it identifies factors and conditions necessary for the success of these models, which include willingness to participate, participant engagement with technology, and project engagement of households and communities, among other factors. Finally, it discusses conflicts and trade-offs in the value propositions of the models, how the three models differ from one another in terms of the value they aim to deliver and some of the open challenges that require further attention by researchers and practitioners.

A New Methodology for Smoothing Power Peaks Produced by Electricity Demand and a Hydrokinetic Turbine for a Household Load on Grid Using Supercapacitors

The power fluctuations produced by electric vehicles represent a drawback in large-scale residential applications. In addition to that, short power peaks could pose a risk to the stability of the electrical grid. For this reason, this study presents a feasibility analysis for a residential system composed of electric vehicle chargers. The objective is focused on smoothing the power fluctuations produced by the charge by a supercapacitor through adequate energy control; in addition, self-consumption is analyzed. Data sampling intervals are also analyzed; the modeling was performed in Matlab software. The results show that there are errors of up to 9% if the data are measured at different sampling intervals. On the other hand, if the supercapacitor is considered, the system saves 59.87% of the energy purchased from the utility grid per day, and the self-consumption of electricity by prosumers can increase up to 73%. Finally, the hydrokinetic/supercapacitor/grid system would save up to 489.1 USD/year in the cost of purchasing electricity from the grid and would increase by 492.75 USD/year for the sale electricity.

Deep reinforcement learning control of electric vehicle charging in the presence of photovoltaic generation

In recent years, the importance of electric mobility has increased in response to climate change. The fast-growing deployment of electric vehicles (EVs) worldwide is expected to decrease transportation-related CO2 emissions, facilitate the integration of renewables, and support the grid through demand–response services. Simultaneously, inadequate EV charging patterns can lead to undesirable effects in grid operation, such as high peak-loads or low self-consumption of solar electricity, thus calling for novel methods of control. This work focuses on applying deep reinforcement learning (RL) to the EV charging control problem with the objectives to increase photovoltaic self-consumption and EV state of charge at departure. Particularly, we propose mathematical formulations of environments with discrete, continuous, and parametrized action spaces and respective deep RL algorithms to resolve them. The benchmarking of the deep RL control against naive, rule-based, deterministic optimization, and model-predictive control demonstrates that the suggested methodology can produce consistent and employable EV charging strategies, while its performance holds a great promise for real-time implementations.

Decarbonizing heat with PV-coupled heat pumps supported by electricity and heat storage: Impacts and trade-offs for prosumers and the grid

Heat pumps play an important role in decarbonizing the heating supply of buildings and they allow to increase the self-consumption of PV electricity, especially when supported by electricity or heat storage. In this study, we develop an open-source model to optimize PV-coupled heat pumps, with and without electricity and heat storage, and we compare their performance for three types of single-family houses with different thermal envelope quality paired with 549 electricity profiles. We analyze trade-offs between prosumer benefits and grid impacts, namely bill minimization, and maximum grid relief, depending on the type of storage and incentives for grid peak reduction (i.e., a capacity-based tariff). We conclude that the use of heat storage reduces the levelized cost of meeting the electricity demand between 13–26% compared to the baseline case without storage, in particular when heat pumps are used for both space heating and domestic hot water (DHW). Regarding total self-consumption rates, both storage technologies, namely batteries and hot water tanks (which supply both space heating and DHW) achieve similar rates ranging between 30–39%. In contrast, batteries are found to be very effective in reducing the peak demand (14–17% compared to the baseline scenario), but only if the retail tariff has a capacity-based component. Interestingly, the quality of the envelope plays a key role and heat pumps can double the power peak demand in poorly insulated houses, with thermal storage increasing the power peak demand further up to 8%, compared to the baseline, regardless of the storage technology. Thus, we conclude that policy makers should promote thermal retrofitting of the building stock to avoid the upgrading of the distribution grid.

Distributed photovoltaics with peer-to-peer electricity trading

Distributed electricity generation technologies, like solar photovoltaic (PV), have achieved rapid development in recent years, but are constrained by some problems such as low marketization and lag in public services. The peer-to-peer (P2P) electricity trading, which allows direct electricity transactions between local consumers and prosumers, has the potential to efficiently distribute the profits coming from self-consumption of PV electricity among all participants. This study proposes a three-layer P2P electricity trading system for communities with high penetration of household distributed PV. The trading system includes a physical layer based on the power grid, an information layer based on a virtual agent network, and a market layer based on a continuous double auction (CDA) mechanism combined with market clearing. By using simulation of trading experiments, a community with 60 houses and 50% PV occupancy is studied as a case. Results show that in one day, 62.5% of the surplus PV electricity of all prosumers actually can be consumed within the community. Through P2P electricity trading of this part of electricity, total incomes of prosumers can increase by 11.5%, and total expense of all users decrease by 7.5%, resulting in that the net expenses of the whole community decrease by 13.8%. It is concluded that P2P electricity trading can unite the whole PV community as a bigger prosumer, and make every residential house in the community share the profits from local PV consumption, which could promote the subsidy-free development and grid parity of household distributed PV in the future.

Identifying Challenges in Engaging Users to Increase Self-Consumption of Electricity in Microgrids

A microgrid’s self-consumption rate reflects its ability to retain its own energy and decrease its reliance on the synchronous grid. This paper investigates the empirical case of a microgrid equipped with photovoltaic (PV) panels and identifies challenges in engaging the microgrid’s users to increase their self-consumption. Accordingly, we explored both the physical and social dimensions of the microgrid. The former involved mapping the electricity consumption and production through an exploratory data analysis, and evaluating the associated price signals, while the latter involved the use of design interventions to explore users’ perceptions of the system. We highlight the problem of price signal impedance, the need for cost reflective pricing and the challenge in designing and extending internal price models in settings with various actors. We address the limitations of price signals, alongside alternative unidimensional signals, and emphasize the need for an integrated approach to a user engagement strategy as well as the challenges that this approach entails. Our results shed light on the complexity of energy communities such as microgrids, and why their implementation can introduce multidimensional challenges that demand cross-disciplinary approaches.

Photovoltaic self consumption analysis in a European low voltage feeder

Electricity self-consumption consists in consumers installing their own small generators, solar photovoltaics mainly. They attempt to save money in the electric bill by producing part of their electrical energy, consequently reducing dependency on the distribution grid. Consumers that simultaneously become producers are usually known as prosumers. This work shows the techno-economical implications, in terms of electric energy, cost savings and grid voltage impact, if self-consumption is deployed in a European low voltage feeder. In the case study, the IEEE European LV test feeder was used. Real data for solar irradiance from 1985 to 2017 were considered for Gijón, a city in the North of Spain. Conclusions may be extrapolated to different locations.

The choice of appropriate generator systems to enhance the renewable energy share in buildings. A comparison between PV-assisted heat pumps and biomass boilers

Low-energy buildings are generally equipped with generation systems driven by renewable sources. Regarding heating and DHW production, two choices appear appropriate: PV assisted heat pumps and biomass boilers. In this paper, by means of TRNSYS dynamic simulations, the non-renewable primary energy was determined for two buildings located in different climatic contexts by varying the PV size to consider the actual self-consumed electricity of commercial devices. Results showed that in cold climates biomass boilers are more suggested, especially in unfavourable climatic zones, whereas the COP of air-water heat pumps is strongly penalized by the outdoor temperatures and in many cases the self-consumed PV electricity does not limit the grid intervention adequately. However, in building with limited thermal energy demands and in favorable climates, suitable PV sizes make heat pumps more performant than biomass boilers. The same calculations were conducted with the quasi-steady approach, in accordance with the Italian building energy certification procedure, observing a favorable scenario in a heating plant equipped with a PV assisted heat pump because it assumes the renewable electricity entirely absorbed, while the accounting of the actual self-consumed share produces a greater demand of non-renewable energy.

Experimental Long-Term Investigation of Model Predictive Heat Pump Control in Residential Buildings with Photovoltaic Power Generation

This article presents a 125-day experiment to investigate model predictive heat pump control. The experiment was performed in two parallel operated systems with identical components during the heating season. One of the systems was operated by a standard controller and thus represented a reference to evaluate the model predictive control. Both test rigs were heated by an air-source heat pump which is influenced by real weather conditions. A single-family house model depending on weather measurement data ensured a realistic heat consumption in the test rigs. The adapted model predictive control algorithm aimed to minimize the operational costs of the heat pump. The evaluation of the measurement results showed that the electrical energy demand of the heat pump can be reduced and the coefficient of performance can be increased by applying the model predictive controller. Furthermore, the self-consumption of photovoltaic electricity, which is calculated by means of a photovoltaic model and global radiation measurement data, was more than doubled. Consequently, the energy costs of heat pump operation were reduced by 9.0% in comparison to the reference and assuming German energy prices. The results were further compared to the scientific literature and short-term measurements were performed with the same experimental setup. The dependence of the measurement results on the weather conditions and the weather forecasting quality are shown. It was found that the duration of experiments should be as long as possible for a comprehensive evaluation of the model predictive control potential.

Micro-economic assessment of residential PV and battery systems: The underrated role of financial and fiscal aspects

The German Federal Government, in order to achieve its renewable energy targets, has promoted the deployment of solar PV. Small residential PV installations coupled with battery energy storage systems are gaining momentum, as the appeal of self-consumption has grown. We conducted an economic analysis to assess the profitability and optimal configuration of these technologies from the perspective of heterogeneous households that are subject to the current German regulatory framework. In this regard, we consider heterogeneous potential for the self-consumption of electricity (e.g. household size, energy efficiency), as well as heterogeneous financial (i.e. metrics, parameters, sources of financing) and fiscal (i.e. tax treatment, tax rate) aspects. We find that the use of alternative financial metrics (i.e. payback period, real internal rate of return and net present value) as criteria for evaluating profitability has a significant impact on the rankings of system configurations. Furthermore, fiscal aspects are crucial to assessing profitability and marginally relevant for optimal system configuration, while financial aspects are of great importance for both. Our results on optimal battery coupling (as opposed to stand-alone PV) show that rates of adoption range between 0% and 94% of the analyzed load profiles, following the variation of such finance-related dimensions (e.g. discount rates, inflation, debt versus equity financing). We conclude that such findings on the impact of such factors are highly relevant in terms of designing cost-efficient and effective policies that aim to foster energy transitions, both in Germany and elsewhere, especially at a time of very low interest rates.

A framework for the study of householders’ engagement with low-carbon energy demand practices in dwellings with grid-connected photovoltaic energy systems

Introduction: This paper introduces a framework to assess householders’ interaction with grid-connected photovoltaic (PV) systems in domestic buildings, in an attempt to research the question To what extent the engagement of occupants in energy demand management practices is relevant for the operational CO 2 emissions reductions in dwellings with on-grid PV systems? The focus is placed on identifying the engagement with low-carbon operation practices and its relevance for final CO2 emissions from electricity consumption. Specifically, PV electricity Self-consumption and energy conservation practices are studied. To this extent, the research builds on i) the energy services approach and ii) the social practices approach to domestic energy demand. The context of owner-occupied houses which have been retrofitted with PV installations in South Wales, UK is taken as an example. Methods: After a brief conceptual review on domestic energy demand, a mixed-methods framework for the study of householders’ engagement with low-carbon energy demand practices is presented, comprising three key aspects: a) the conditions for the practices to occur, b) frequency with which householders enact the practices, and c) the estimation of final operational CO2 emissions performance. Results: As part of ongoing research work, a framework to study households’ engagement with low-carbon energy demand practices in buildings with grid-connected PV technology is proposed; focusing on the obtention of a socio-technical lecture to complement other sources of in-use assessment data. Conclusions: Besides single case-studies, the framework has potential applications in recognising and grouping households’ engagement profiles. In this way, it is suggested that the framework might facilitate the analysis when extensive assessments are needed; such as in public policy evaluation or demand response studies. Grant Support: This work is funded by CONICYT PFCHA/DOCTORADO BECAS CHILE/2018 - 72180375.

Photovoltaic self-consumption is now profitable in Spain: Effects of the new regulation on prosumers’ internal rate of return

Abstract: Whereas Spain used to have one of the most restrictive photovoltaic self-consumption (PVSC) regulations in the world, the new regulation (RD-L 15/2018 & RD 244/2019) improves the economic conditions of PVSC systems, simplifies administrative procedures and allows shared self-consumption. We analyze the impact of the new PVSC regulation on residential, commercial and industrial prosumers’ profitability (internal rate of return). We provide a wide range of results that allow us to explore future profitability depending on the evolution of installation costs, the opportunities of shared self-consumption or storage, and even the potential emergence of new business models. We find that all segments obtain now positive profitability in average conditions. Whereas the residential segment has the lowest profitability level, it has the highest potential by decreasing installation costs and increasing the share of self-consumption, given its higher retail prices. Finally, we identify potential new business models by exploiting the prices and costs differentials across segments and maximizing the share of self-consumed electricity. PVSC systems with industrial costs exploiting residential markets could achieve 35% profitability by reaching 75% self-consumption, and even higher than 40% when self-consumption exceeds 85%.

Integrating LCA with Process Modeling for the Energetic and Environmental Assessment of a CHP Biomass Gasification Plant: A Case Study in Thessaly, Greece

The energetic and environmental performance of a cogeneration biomass gasification plant, situated in Thessaly, Greece is evaluated via a methodology combining process simulation and Life Cycle Assessment (LCA). Initially, the gasification process of the most common agricultural residues found in the Thessaly region is simulated to establish the effect of technical parameters such as gasification temperature, equivalence ratio and raw biomass moisture content. It is shown that a maximum gasification efficiency of approximately 70% can be reached for all feedstock types. Lower efficiency values are associated with increased raw biomass moisture content. Next, the gasifier model is up-scaled, achieving the operation of a 1 MWel and 2.25 MWth cogeneration plant. The Life Cycle Assessment of the operation of the cogeneration unit is conducted using as input the performance data from the process simulation. Global Warming Potential and the Cumulative Demand of Non-Renewable Fossil Energy results suggest that the component which had the major share in both impact categories is the self-consumption of electricity of the plant. Finally, the key conclusion of the present study is the quantification of carbon dioxide mitigation and non-renewable energy savings by comparing the biomass cogeneration unit operation with conventional reference cases.

Impact of electricity market feedback on investments in solar photovoltaic and battery systems in Swedish single-family dwellings

The profitability of investments in photovoltaics (PVs) and batteries in private households depends on the market price of electricity, which in turn is affected by the investments made in and the usage of PVs and batteries. This creates a feedback mechanism between the centralised electricity generation system, and household investments in PVs and batteries. To investigate this feedback effect, we connect a local optimisation model for household investments with a European power generation dispatch model. The local optimisation is based on the consumption profiles measured for 2104 Swedish households. The modelling compares three different scenarios for the centralised electricity supply system in Year 2032, as well as several sensitivity cases. Our results show total investment levels of 5–20 GWp of PV and 0.01–10 GWh of battery storage capacity in Swedish households in the investigated cases. These levels are up to 33% lower than before market feedback is taken into account. The profitability of PV investments is affected most by the price of electricity and the assumptions made regarding grid tariffs and taxes. The value of investments in batteries depends on both the benefits of increased self-consumption of PV electricity and market arbitrage.

Techno-economic comparison of buildings acting as Single-Self Consumers or as energy community through multiple economic scenarios

The European Union has set ambitious targets to move towards a society with high penetration of renewable energy sources. In the forthcoming energy transition, Energy Communities (EC), i.e., legal entities where different actors, including citizens, cooperate in energy generation, storage and management, will play a crucial role. The present work simulates the energy flows and assesses the potential economic benefits of a cluster of buildings acting collectively as an energy community – a specific case study is set in northern Italy by comparing the EC performance with a configuration where customers act as Single Self-Consumers (SSCs). Pending the transposition of EU Directives to binding national laws, due by 2021, different supporting tariffs (economic scenarios) have been simulated in order to determine which scheme will support more effectively the integration of Energy Communities in the national energy market. Results show that ECs (i.e., customers acting collectively as energy prosumers) are able to accelerate the diffusion of building-integrated renewable energy sources (RES), resulting in higher overall self-consumption rates than SSCs. Self-consumed electricity generates savings on the energy bill of EC, and we calculated positive economic performance indicators for all the analysed economic scenarios. The sensitivity analysis carried out on system and transport charges of the electricity bill shows their remarkable impact on the economics making the EC less attractive for investors and citizens without proper supporting schemes.

Li-ion battery storage in private households with PV systems: Analyzing the economic impacts of battery aging and pooling

Abstract This paper investigates the economic viability of Li-ion battery storage for households, taking into account the economic costs of battery aging and the gains from battery pooling concepts. To this end, a techno-economic model is proposed that enables to quantify the increase in self-consumption of electricity from a solar photovoltaic system by means of a home battery storage system. Regarding battery aging, we find that the longest battery lifetimes can be achieved with the highest state-of-charge limit, which is, however, not economically preferable due to limited self-consumption. Three pooling concepts presently promoted in Germany are studied as well (Sonnen, Caterva, Fenecon). Although one of the three battery pooling concepts was identified as not being economical, namely the case of Sonnen, our evaluation shows that profitability can, in principle, be achieved with home battery pooling concepts. We find that the battery lifetime varies greatly from 11.6–26.5 years, depending on the state-of-charge limits set, with important economic implications on the overall cost effectiveness, and that the level of self-consumption of PV power is about 67.5% in the reference case, compared to 59.4–66.4% for the three battery pooling models analyzed.

On the Trade-Off Between Environmental and Economic Objectives in Community Energy Storage Operational Optimization

The need to limit climate change has led to policies that aim for the reduction of greenhouse gas emissions. Often, a trade-off exists between reducing emissions and associated costs. In this article, a multi-objective optimization framework is proposed to determine this trade-off when operating a Community Energy Storage (CES) system in a neighbourhood with high shares of photovoltaic (PV) electricity generation capacity. The Pareto frontier of costs and emissions objectives is established when the CES system would operate on the day-ahead spot market. The emission profile is constructed based on the marginal emissions. Results show that costs and emissions can simultaneously be decreased for a range of solutions compared to reference scenarios with no battery or a battery only focused on increasing self-consumption, for very attractive CO2 abatement costs and without hampering self-consumption of PV-generated electricity. Results are robust for battery degradation, whereas battery efficiency is found to be an important determining factor for simultaneously decreasing costs and emissions. The operational schedules are tested against violating transformer, line and voltage limits through a load flow analysis. The proposed framework can be extended to employ a wide range of objectives and/or location-specific circumstances.

Rising with the sun? Encouraging solar electricity self-consumption among apartment owners in Sweden

Studies suggest that householders who turn prosumers become more energy aware, change their pattern of electricity use and may even start to engage in other pro-environmental activities. However, few of these studies were equipped to investigate such causal relationships—mainly because most prosumers are inherently self-selected. However, as real estate companies and building owners have begun installing photovoltaics on their customers’ behalf, a new breed of non-self-selected prosumers is emerging, which presents new opportunities to address questions of causality and thus improve our understanding of the possible implications of a more prosumer-dense future. Using a sample of 54 apartment households with a shared rooftop PV installation, this article presents the first causal analysis on non-self-selected prosumers’ response to information about having become prosumers, what that means for themselves and the collective they are part of, how to self-consume solar electricity and why they should do so. Using a stepped wedge design and stratified randomization procedure we were able to design an experimental study with sufficient power. A panel regression model and various statistical analyses on pre and post treatment survey- and electricity use data were used to evaluate the intervention. In line with studies of self-selected prosumers, the self-reported measures suggest that householders have shifted the use of major appliances to increase their self-consumption. However, based on the electricity use data, we find no evidence of a such a shift and no indications of spillovers to other pro-environmental behaviours—highlighting the need to use multiple measures to assess behavioural change.

Photovoltaic Plant Optimization to Leverage Electric Self Consumption by Harnessing Building Thermal Mass

The self-consumption without surplus to the grid is one of the aspects of the new Spanish law for prosumers. Increasing the share of renewable energy sources into the grid inherently leads to several constraints. The mismatch between the energy demand and the renewable energy production, which is intermittent in nature, is one of those challenges. Storage offers the possibility to decouple demand and supply, and therefore, it adds flexibility to the electric system. This research evaluates expanding electricity self-consumption without surplus to the grid by harnessing thermal mass storage in the residential sector. The methodology is investigated by using a variable refrigerant flow air conditioner system. Because there is no option to export the excess capacity to the grid, this research proposes an approach to profiting from this surplus energy by activating structural thermal mass, which is quantified from the information acquired using a building energy model. For this purpose, an EnergyPlus model of a flat in Pamplona (Spain) was used. The optimization analysis was based on a set-point modulation control strategy. Results show that under adequate climatological circumstances, the proposed methodology can reduce the total electric energy from the grid between by 60– 80 % .

Report on a Plus-Energy District with Low-Temperature DHC Network, Novel Agrothermal Heat Source, and Applied Demand Response

District heating and cooling networks can pose the possibility of including a variety of renewable energy sources as well as waste heat into a district’s heat supply concept. Unfortunately, low demand densities as they increasingly occur through higher building energy standards and in rural areas render conventional heating and cooling networks inefficient. At the same time, power-to-heat is becoming more and more important to make use of a larger amount of renewable energy sources on the electrical side by providing more flexibility by means of demand response and demand-side management. Within this work, a rural Plus-Energy settlement is presented addressing those topics by a low-temperature district heating and cooling network connected to a novel agrothermal collector supplying 23 residential buildings with decentralized heat pumps and PV systems. The collector, the network, and six of the buildings are equipped with comprehensive monitoring equipment. Within those buildings, forecast and optimization algorithms are implemented to adapt their heat pump operation to enable an increase of self-consumption, to include flexible electricity tariffs, and also to participate in power markets. Thereby, for the low-temperature district heating and cooling network, it has been shown that the concept can operate in the future at competitive heat costs. On the building level, up to 50% of cost savings could be achieved under ideal conditions with the optimization of the self-consumption of PV electricity. However, to ensure optimal results, the individual system components have to be dimensioned for this task.