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Techno-Economic Assessment of Battery Systems for PV-Equipped Households with Dynamic Contracts:

Dynamic energy contracts, offering hourly varying day-ahead prices for electricity, create opportunities for a residential Battery Energy Storage System (BESS) to not just optimize the self-consumption of solar energy but also capitalize on price differences. This work examines the financial potential and impact on the self-consumption of a residential BESS that is controlled based on these dynamic energy prices for PV-equipped households in the Netherlands, where this novel type of contract is available. Currently, due to the Dutch Net Metering arrangement (NM) for PV panels, there is no financial incentive to increase self-consumption, but policy shifts are debated, affecting the potential profitability of a BESS. In the current situation, the recently proposed NM phase-out and the general case without NM are studied using linear programming to derive optimal control strategies for these scenarios. These are used to assess BESS profitability in the latter cases combined with 15 min smart meter data of 225 Dutch households to study variations in profitability between households. It follows that these variations are linked to annual electricity demand and feed-in pre-BESS-installation. A residential BESS that is controlled based on day-ahead prices is currently not generally profitable under any of these circumstances: Under NM, the maximum possible annual yield for a 5 kWh/3.68 kW BESS with day-ahead prices as in 2023 is EUR 190, while in the absence of NM, the annual yield per household ranges from EUR 93 to EUR 300. The proposed NM phase-out limits the BESS’s profitability compared to the removal of NM.

Veilig en autonoom regelend PV-laadplein met DC-distributie: vertrouwelijk rapport

Het veilig en autonoom regelend PV-laadplein met DC-distributie (VAP-DC) is een project waarin het ontwerpen, bouwen, testen en operationeel maken van een DC-netwerk (gelijkspanning) wordt aangetoond.Het systeem op het parkeerdek kan zonder AC (wisselspanning) opereren zoals het verzorgen van verlichting, het elektrische laden en ontladen van EV’s (Electrical Vehicles), waaronder het overbrengen van elektrische lading van de ene naar de andere(n). Het PV-(Photo Voltaic)systeem zorgt voor de energie, en kan het DC-microgrid ook zelf activeren, waardoor een autonoom systeem ontstaat.Het systeem werkt geheel autonoom (A) met een eigen zeer snel reagerend congestiemanagementmethode, modulaire Droop Rate Control strategie. In dit ontwerp is als extra veiligheid een safetywire voorzien, waar de AFE (Active Front End), laadvoorzieningen en PV-systeem op zijn aangesloten.Eventueel kan de AFE worden ingeschakeld, zodat er een bi-directionele vermogenstransfer kan plaatsvinden tussen de twee geïsoleerde AC- en DC-netten.Het TN-S stelsel met een PE-draad voor veiligheid en afvoer van hoogfrequente stromen, en een aparte aarde, is de beste methode om een veilig, autonoom, droop rate controlled grid te maken. Metingen met ingebouwde referentie-elektrode voor onderzoek naar mogelijke zwerfstromen, laat geen verband zien met het wel of niet actief zijn van de PV-panelen en/of de laadpalen. Een verklaring hiervoor kan zijn dat de lekstromen die ontstaan via de stalen constructie goed worden afgevoerd.Aangetoond is dat het DC-grid zowel zelfstandig als naast het AC-grid kan bestaan om energie te leveren voor DC-producten zoals bidirectionele EV-laadplaatsen en verlichting zodat er een nieuw instrument beschikbaar is om de energietransitie te realiseren. Dit onderzoek toont aan dat het mogelijk is om in Nederland gelijkstroominstallaties breed uit te rollen.Met leden van de normcommissie NEN TC 64 binnen het onderzoekteam en de commissie zelf is het ontwerp en de realisatie van de onderzoekinstallatie uitvoerig besproken. Deze pilot vormt daarmee een belangrijke basis voor verdere normering van DC-installaties in de NEN 1010 en NPR 9090. Verder onderzoek is nodig om deze norm en regelgeving breed in te passen.Dit onderzoek biedt onderbouwing bij de verdere ontwikkeling van actieve gelijkstroominstallaties.Er is grote interesse van diverse bedrijven en (overheids-)instanties naar de ervaringen en oplossingen die het onderzoek bracht. Hierdoor ervaarde het projectteam de nut en noodzaak dat er onderzoek gedaan wordt naar systemen die de huidige overbelastingsproblemen kunnen minimaliseren of om in ieder geval alternatieven aan te kunnen bieden.

Design of wind and solar energy supply, to match energy demand

Renewable energy sources have an intermittent character that does not necessarily match energy demand. Such imbalances tend to increase system cost as they require mitigation measures and this is undesirable when available resources should be focused on increasing renewable energy supply. Matching supply and demand should therefore be inherent to early stages of system design, to avoid mismatch costs to the greatest extent possible and we need guidelines for that. This paper delivers such guidelines by exploring design of hybrid wind and solar energy and unusual large solar installation angles. The hybrid wind and solar energy supply and energy demand is studied with an analytical analysis of average monthly energy yields in The Netherlands, Spain and Britain, capacity factor statistics and a dynamic energy supply simulation. The analytical focus in this paper differs from that found in literature, where analyses entirely rely on simulations. Additionally, the seasonal energy yield profile of solar energy at large installation angles is studied with the web application PVGIS and an hourly simulation of the energy yield, based on the Perez model. In Europe, the energy yield of solar PV peaks during the summer months and the energy yield of wind turbines is highest during the winter months. As a consequence, three basic hybrid supply profiles, based on three different mix ratios of wind to solar PV, can be differentiated: a heating profile with high monthly energy yield during the winter months, a flat or baseload profile and a cooling profile with high monthly energy yield during the summer months. It is shown that the baseload profile in The Netherlands is achieved at a ratio of wind to solar energy yield and power of respectively Ew/Es = 1.7 and Pw/Ps = 0.6. The baseload ratio for Spain and Britain is comparable because of similar seasonal weather patterns, so that this baseload ratio is likely comparable for other European countries too. In addition to the seasonal benefits, the hybrid mix is also ideal for the short-term as wind and solar PV adds up to a total that has fewer energy supply flaws and peaks than with each energy source individually and it is shown that they are seldom (3%) both at rated power. This allows them to share one cable, allowing “cable pooling”, with curtailment to -for example-manage cable capacity. A dynamic simulation with the baseload mix supply and a flat demand reveals that a 100% and 75% yearly energy match cause a curtailment loss of respectively 6% and 1%. Curtailment losses of the baseload mix are thereby shown to be small. Tuning of the energy supply of solar panels separately is also possible. Compared to standard 40◦ slope in The Netherlands, facade panels have smaller yield during the summer months, but almost equal yield during the rest of the year, so that the total yield adds up to 72% of standard 40◦ slope panels. Additionally, an hourly energy yield simulation reveals that: façade (90◦) and 60◦ slope panels with an inverter rated at respectively 50% and 65% Wp, produce 95% of the maximum energy yield at that slope. The flatter seasonal yield profile of “large slope panels” together with decreased peak power fits Dutch demand and grid capacity more effectively.

Soiling and cleaning solar parks at two locations in the Netherlands

Case: PV generation and Electricity demand at the Johan Cruijff Arena

PV systems are used more and more. Not always is it possible to install them in the optimal direction for maximum energy output over the year. At the Johan Cruijff ArenA the PV panels are placed all around the roof in all possible directions. Panels oriented to the north will have a lower energy gain than those oriented to the south. The 42 panel groups are connected to 8 electricity meters. Of these 8 energy meters monthly kWh produced are available. The first assignment is to calculate the energy gains of the 42 panel groups, and connect these in the correct way with the 8 energy meter readings, so simulated data is in accordance with measured data.Of the year 2017 there are also main electricity meter readings available for every quarter of an hour. A problem with these readings is that only absolute values are given. When electricity is taken of the grid this is a positive reading, but when there is a surplus of solar energy and electricity is delivered to the grid, this is also a positive reading. To see the effect on the electricity demand of future energy measures, and to use the Seev4-City detailed CO2 savings calculation with the electricity mix of the grid, it is necessary to know the real electricity demand of the building.The second assignment is to use the calculations of the first assignment to separate the 15 minute electricity meter readings in that for real building demand and for PV production.This document first gives information for teachers (learning goals, possible activities, time needed, further reading), followed by the assignment for students.

Outdoor performance of Infra integrated PV

The Netherlands is aiming for the roll-out of more solar PV. However like many densely populated countries, the country is running into issues of lack of space. Opportunities around infrastructural works like highways provide space without compromising the landscape. Examples of this double use are already developed and demonstrated, like for instance sound barriers and solar roads. New is the combination of solar PV with traffic barriers. This has a big potential since the Dutch main road network had 7.500 km of guiderail and the construction to put PV on is already there. In the MESH (Modular E cover for Solar Highways) project a consortium of knowledge institutes, a province and companies developed a prototype and tested it in a pilot. The consortium consists of TNO, Solliance (in which TNO is a partner, a high-end research institute for flexible thin film solar cells such as CIGS and Perovskite), Heijmans Infra (focusing mainly on the construction, improvement and maintenance of road infrastructure, including guiderails), DC Current (applying innovations with regard to power optimizers for the linear PV application), the Province of Noord-Holland (which acts as a leading customer) and the Amsterdam University of Applied Sciences (AUAS) as a knowledge institution that links education and research. In this project the theme Sustainable Energy Systems of AUAS is involved with both lecturers and student groups. In the project, Solliance investigated and developed the flexible thin film PV technology to be applied with a focus on shape and reliability. TNO and Heijmans developed a modular casing concept and a fastening system that allows quick installation on site. DC Current worked on the DC management with regard to voltage, electrical safety and minimizing failure in case of collision. At the end of the project, the partners in the consortium have validated knowledge about how to integrate PV into the guiderail and can start with the scaling up of the technology for commercial applications. In order to meet the various requirements for traffic safety on the one hand and generating electricity on the other hand, the Systems Engineering methodology was leading during the project. In the project we first built a small, but full scale prototype and invited safety experts to evaluate the design. With this feedback we made a redesign for the pilot. This pilot is placed on the highway as safety barrier and tested for a year. In a presentation at EU PVSEC18 [1] K.Sewalt reported on the design phase. This time we want to present the results of our test phase and give answers on our research questions.