Prevedere per ridurre i costi di produzione



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SOLUZIONE SISTEMI IBRIDI E STOCCAGGIO

L’ibridazione del solare con gruppi diesel, dello stoccaggio o di un’altra fonte rinnovabile, è in pieno sviluppo, in quanto consente di fornire un kWh competitivo in zone lontane dalla rete elettrica. L’obiettivo del gestore consiste appunto nel gestire al meglio queste diverse fonti, consentendogli così di ridurre il costo del MWh prodotto. Ciò necessita ovviamente di un migliore utilizzo della produzione solare e quindi di una previsione della produzione eccellente, e questo in diversi orizzonti temporali.

La nostra soluzione consiste da un lato nell’apportare una previsione dal giorno prima all’indomani di ottima qualità, in quanto adattata alle specificità del sito e, dall’altro, nel prevedere dettagliatamente la produzione della mezz’ora successiva. Quest’ultimo punto è essenziale per poter ottimizzare il controllo del sistema. In base a queste situazioni, verrà implementato SteadySat (previsioni utilizzando immagini satellitari) o SteadyEye (previsioni a partire da immagini scattate dalla centrale), a complemento di SteadyMet (previsioni basate su modelli meteorologici). Con alcuni dei nostri clienti, abbiamo implementato tutti i nostri fondamenti tecnologici, soprattutto in siti che associano produzione fotovoltaica e stoccaggio.

Hybrid Systems

An hybrid energy system is generally constituted by classic energy sources (a fuel generator for example), by renewable energy sources (such as solar energy, biomass or wind turbines), a storage solution and an energy management system (EMS).They may be grid connected or not. These systems address perfectly the needs in energy of poorly connected areas such as islands, micro-grids, even completely off-grid areas like rural areas or some mining sites for instance. The largest possible PV implementation allows a significant drop of the average cost of the energy produced by such systems.

 

Variability

Solar energy, because of its meteorological dependency, may generate significant production variations. Storing the energy can partially tackle this issue but storage technology costs remain very high. As a consequence, an efficient forecasting solution is today the most economical solution to predict and manage these energy production variations. In the case of an hybrid system, the use of a ground based sky imager is the most suitable instrument to forecast at a high update rate on a very short term time horizon the expected power drops. This forecast is then taken into account by the EMS which will drive the associated resources (storage or fuel generator for example). This very short term forecasting solution allows to include more PV power in an hybrid system, to reduce the use of other more expensive resources (gensets) while maintaining and guaranteeing the stability of the whole system.

 

SteadyEye Solution

The SW-02 sky imager, deployed on site, is taking hemispherical photos of the sky up to every minute. These images are then processed with a forecasting algorithm developed by Steadysun, which predict the possible impact of the clouds on the PV production. This algorithm will generate very short term solar production forecasts (from 1 minute to 1 hour) which are transmitted to the management software of the hybrid system. The SteadyEye service solution allows, thereby, to obtain on the chosen time horizon a production forecast for one or several PV installations on a 10 km2 area. This forecast can be updated every minutes.

 

Off-Grid Sites

The issue is quite similar in the case of an off-grid site, like a rural area or mining site, but the solution must in addition operate taking into account the lack of telecommunications network as well. In this case, the steadyEye forecasting service may operate using a local PC which will run the forecasting software on-site and will send the forecast files to the site energy management system (EMS). A simple integration with a logic programmable controller or a SCADA system can be implemented. Besides operational cost-cutting (maintenance and fuel costs), SteadyEye solution allows an increase in the installed PV power and the share of the solar energy in the energetic mix of the system.

Further reading: Sky Imaging – A Competition for Storage in Solar-Diesel-Hybrid Applications?

Application Use Case: Juergen Zimmermann – ABB Australia Pty Ltd – Offgrid Hybrid Power Systems – Can Solar Forecasting reduce LCOE?