Solar energy for residential electric vehicle charging in Northern Norway – a feasibility study

Source at https://mobilityintegrationsymposium.org/proceedings/.This paper presents a study of the potential for using photovoltaic (PV) solar energy systems for residential charging of electric vehicles (EVs) in Northern Norway. The objective is to investigate the load match between PV yield and uncontrolled EV charging, in terms of self-consumption and self-sufficiency. The load profile for EV charging is retrieved from a study by the Norwegian Water Resources and Energy Directorate (NVE), based on measurements and a survey sent to EV owners. An adjusted example EV profile that better represents a single household is also proposed. Other household loads are taken into account using measured data from ten single-family buildings in Tromsø, retrieved from local power company Troms Kraft. The PV yield is simulated for roof-mounted and façade-mounted 4.2 kWp system with different orientations, using PVsyst. The results show that the load match between PV yield and uncontrolled EV charging is poor, as PV power has a peak at noon and the EV charging is highest during afternoon and night-time. A design option for increased load-match (but lower total yield) is mount the PV system facing west, since the PV power peak is shifted towards the afternoon. Solutions for increasing the load match, provide autonomy and reduce negative impacts on the grid are discussed, for example the use of residential battery storage and controlled EV charging. Based on the results, the authors propose that more focus is given to workplace charging combined with solar energy, since this would increase the load match significantly

The pure PV-EV energy system – A conceptual study of a nationwide energy system based solely on photovoltaics and electric vehicles

The objective of this conceptual study is to reveal the substantial potential and synergy of solar energy and electric vehicles (EVs) working together. This potential is demonstrated by studying the feasibility of a nationwide energy system solely reliant on solar energy and EVs. Photovoltaic (PV) solar energy is already an important energy source globally, but due to its intermittency it requires energy storage to balance between times of high and low production. At the same time, a global drive is underway in the transport sector: the change from internal combustion engines to EVs. Cars are in fact stationary 95% of the time, and when the vehicle is connected to the grid, the EV battery can regulate the intermittent PV source using vehicle-to-grid (V2G) technology. This paper presents a conceptual study of a pure PV-EV based energy system, with Spain as a case study. Provided that Spain’s entire fleet of 29.4 million road going vehicles is switched to EVs, the study shows that 3.45 billion m2 of PV (73 m2 per capita) could give Spain a completely self-reliant energy system. The theoretical study is based on a combination of measured values, simulations, and assumptions. The conclusion of the analysis is undoubtedly extraordinary, namely that an entire country like Spain can power its complete energy system solely on PV, using EVs as the only energy storage resource

Narrowband Searches for Continuous and Long-duration Transient Gravitational Waves from Known Pulsars in the LIGO-Virgo Third Observing Run

Isolated neutron stars that are asymmetric with respect to their spin axis are possible sources of detectable continuous gravitational waves. This paper presents a fully coherent search for such signals from eighteen pulsars in data from LIGO and Virgo's third observing run (O3). For known pulsars, efficient and sensitive matched-filter searches can be carried out if one assumes the gravitational radiation is phase-locked to the electromagnetic emission. In the search presented here, we relax this assumption and allow both the frequency and the time derivative of the frequency of the gravitational waves to vary in a small range around those inferred from electromagnetic observations. We find no evidence for continuous gravitational waves, and set upper limits on the strain amplitude for each target. These limits are more constraining for seven of the targets than the spin-down limit defined by ascribing all rotational energy loss to gravitational radiation. In an additional search, we look in O3 data for long-duration (hours-months) transient gravitational waves in the aftermath of pulsar glitches for six targets with a total of nine glitches. We report two marginal outliers from this search, but find no clear evidence for such emission either. The resulting duration-dependent strain upper limits do not surpass indirect energy constraints for any of these targets. © 2022. The Author(s). Published by the American Astronomical Society

Photovoltaic-thermal systems for zero emission residential buildings

This thesis concerns the use of solar energy in energy efficient buildings. More precisely, the topic is photovoltaic-thermal (PV/T) solar energy systems, and how these can be used to provide renewable energy in zero emission buildings. PV/T modules are a hybrid between photovoltaic (PV) modules and solar thermal collectors, and therefore generate electricity and thermal energy simultaneously. The objective of the thesis was to investigate the potential of PV/T systems to minimize the life cycle greenhouse gas emissions of a residential building. The main research method in this thesis has been simulation of solar energy systems in buildings. Using simulations, PV/T systems have been compared to other solar energy systems with separate PV modules and solar thermal collectors. The simulation studies were performed in the simulation programs Polysun and PVsyst, and were based on commercial solar energy products available on the current market. The use of heat pumps, air-source and ground-source, in combination with solar energy systems was also studied. Two case buildings, the ZEB residential concept and the Living Lab, have been used in the simulation studies. The buildings are two of the pilot buildings of the Norwegian Research Centre for Zero Emission Buildings (the ZEB Centre). Both buildings are single family residential buildings located in Central or Southern Norway, and are designed to meet the Norwegian passive house requirements. The embodied emissions of the solar energy systems were determined using elements of life cycle assessments (LCA). A review of previous research found few studies of the environmental impact of PV/T modules, especially using industrially produced modules. The embodied emissions of such a PV/T module was therefore determined in this thesis, based on a combination of data from databases and information from module producers. The embodied emissions of the case buildings and the other solar energy systems studied were determined using a combination of databases and previously published research in the ZEB Centre. The results show that PV/T systems can be a good renewable energy solution for energy efficient buildings, but that their performance is highly dependent on how the system is designed and what control strategies are used. The simulations showed that the systems with PV/T modules typically had higher primary output per unit area than the systems with separate PV modules and solar energy collectors, but that this also depended on how the solar energy systems were designed. However, due to a higher use of electricity to run e.g. circulation pumps, the energy balance of the whole building was not improved compared to systems with separate solar technologies. The thermal output of PV/T systems are typically of a lower temperature than that of solar thermal collectors, and the technology should therefore be used in energy systems where low temperature heat is valuable. The combination of PV/T modules and ground source heat pumps showed potential to increase the efficiency of a building’s energy system compared to other solar energy technologies, especially when PV/T modules were installed on the source side of the heat pump. However, the studies also showed that it is a complex task to design such as system, and the energy demand required to operate it can easily be higher than the gains. No clear benefit from cooling of PV/T modules were found in the simulations in this thesis. In terms of emissions, no benefit of PV/T modules was found in the case studies. The generic PV/T module which was modelled had around 30% higher embodied emissions than a comparable PV module, and the increase in energy output from the PV/T module was not high enough to allow for this. It was in general found to be quite difficult to reach a net zero emission balance for a building, at least if embodied emissions of materials were included. A large solar energy installation was necessary to reach a balance, which sometimes resulted in non-optimal system designs. Nearly zero emission buildings, or zero emission neighbourhoods, might be a more feasible goal for new buildings. Even though all of the studied solar energy systems were found to be the source of a high share of the total embodied emissions of a building, they also contributed to a large reduction in greenhouse gas emissions over their lifetime. That is, solar energy installations, PV/T systems included, contribute to reduced emissions also in a Scandinavian climate

Electric Aviation: A review of concepts and enabling technologies

Electric aviation has become an important area of research following the rapid growth of the aviation industry, which directly corresponds to significant growth in aviation-related emissions. Despite the promising emission reduction potential of electric airplanes, several technological and regulatory challenges restrict the realization of this new regime of sustainable air transport. Significant advancements in enabling technologies, new certification standards, and infrastructural development are required to make commercial air transport viable. This review paper surveys scholarly and industrial literature to identify the main technological areas of electric aviation, including battery technology, electric machine technology, airframe, and propulsion technologies; where the technology currently stands, their future projections, and their challenges. Several electric aircraft design concepts, prototypes, and existing products are also surveyed in this study to identify the constraints of technological advancement and regulatory frameworks that could impede the realization and time to market the proposed electric airplanes