Positive balancing service by solar virtual power plants

During the past years, a large amount of photovoltaic (PV) capacity has been installed in Belgium. The main driver for this was the abundant government support (GreenPower Certicates). However, during the last few years, the support for new installations has been withdrawn and new PV capacity ceased. In previous research, it has been proven that selling PV energy of existing plants directly on the wholesale market is not feasible due to the large share of green power certicates awarded to these plants. However, the price of green power certicates has dropped signicantly and hence the balance between certicate and commodity revenue is restored. This paper investigates the possibility of providing positive balancing services to the transmission system operator by aggregating solar power in a technical Virtual Power Plant. The paper concludes that it seems not interesting, neither economically nor energetically, to keep solar plants solely for positive balancing purposes. Combination of solar power with other sources or consumers can however be profitable, as solar power is quickly switched in case it is needed to react fast

Smart microgrids and virtual power plants in a hierarchical control structure

In order to achieve a coordinated integration of distributed energy resources in the electrical network, an aggregation of these resources is required. Microgrids and virtual power plants (VPPs) address this issue. Opposed to VPPs, microgrids have the functionality of islanding, for which specific control strategies have been developed. These control strategies are classified under the primary control strategies. Microgrid secondary control deals with other aspects such as resource allocation, economic optimization and voltage profile improvements. When focussing on the control-aspects of DER, VPP coordination is similar with the microgrid secondary control strategy, and thus, operates at a slower time frame as compared to the primary control and can take full advantage of the available communication provided by the overlaying smart grid. Therefore, the feasibility of the microgrid secondary control for application in VPPs is discussed in this paper. A hierarchical control structure is presented in which, firstly, smart microgrids deal with local issues in a primary and secondary control. Secondly, these microgrids are aggregated in a VPP that enables the tertiary control, forming the link with the electricity markets and dealing with issues on a larger scale

Renewable energy balancing with thermal grid support

Waste heat valorisation in process industry is a common strategy today. The residual heat is converted to electricity by using steam turbines or organic Rankine cycles. As this energy conversion is likely constructed as an integral cooling capacity for the primary process, loss of electricity production will result in reduced process cooling and hence production capacity loss. This restriction prevents these generators to deliver supporting services to the electrical grid. In this paper, it is proven that coupling waste heat recovery with a district heating network provides flexibility to the electricity generation while ensuring cooling capacity to the process. This flexibility can be utilised by a Virtual Power Plant (VPP), e. g., to compensate for the variable output of renewable energy sources. Today, the power fluctuations are only compensated by traditional power plants (gas, coal) due to the scale and flexibility of these power plants. In this paper, a strategy is defined to balance variable (renewable) production with industrial waste heat. As such, some grid support tasks can be transferred from the central power plants to decentralised generation units. The backup of the variable sources is provided by utilising the local available capacity, while maintaining or improving energy efficiency of exothermal industrial processes. Operational boundaries are defined and new challenges identified. In this paper, firstly, the heat sources available for this concept are identified. Secondly, the properties of the different conversion technologies are described. Thirdly, the benefits of a virtual power plant utilising waste heat are determined. Finally, this VPP concept is verified by means of a case study in Belgium, Ostend Energy port. Available heat from biomass, chemical processing and waste incineration is used as primary energy source to balance local renewable production

Virtual sector profiles for innovation sharing in process industry : sector 01: chemicals

Production data in process industry are proprietary to a company since they are key to the process design and technology expertise. However, data confidentiality restrains industry from sharing results and advancing developments in and across process sectors. Using virtual profiles that simulate the typical operating modes of a given process industry offers an elegant solution for a company to share information with the outside world. This paper proposes a generic methodology to create sector blueprints and applies it to the chemicals industry. It details the profile of a typical chemical site based on essential units and realistic data gathered from existing refineries and chemical plants

Microgrids en virtual power plants: hoe beter gebruik maken van hernieuwbare energie

De introductie van hernieuwbare energiebronnen loopt niet van een leien dakje. De aanwezige netinfrastructuur is niet altijd en overal geschikt om naast verbruikers ook producenten te verbinden. Door de vele, vaak tegenstrijdige, belangen en hoge kosten zijn nieuwe interconnectielijnen bovendien projecten van lange adem. Beter omgaan met de bestaande netcapaciteit is dus een must. Dit kan door gebruik te maken van intelligente integratiestrategieën zoals microgrids en Virtual Power Plants (VPP)