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sunlightfuture

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  1. Hi, We have had some concerns with the accuracy of financial modelling when using the time-controlled charging but today we have inadvertently stumbled on a test case where it demonstrates that this aspect of the modelling does not appear to be working correctly. We are modelling a site for a client and we had intended on suggesting the client uses off-peak charging to increase the battery utility. When I reviewed the project I found we had made a mistake in the tariff configuration and had used a single rate tariff From-grid tariff (so there was no off-peak period). The Feed-In tariff rate and the From-grid tariff were set at the same rate. This means that if we activated the Time-control to set the SOC target value to charge overnight to 100% the battery would get used more (incuring increased losses) but not generate much of a change in the rate of return (savings) as the increase in power pulled from the grid would be offset by the increase in Feed-In Tariff, both at the same rate. However, we instead saw that the more forced charging we applied the results improved considerably: No Time-control charging: Time-controlled charge to 100% between 01:00-04:00: We set off-peak rates correctly with an off-peak rate 75% lower than the peak rate and had a result broadly similar result: Digging down into the data it seemed that the difference suggested that PV Sol was not accounting for the cost of electricity used to charge the battery in the time-controlled period. We checked the losses due to charging/discharging and these were higher in the Forced charge scenario, as expected. The resultant difference in financial projections was troubling. In this example the amortization period dropped from 11.5 to approx 7 years (regardless of low we set the off-peak rate). This cannot be correct. For reference, this is the Time-controlled charging schedule we used is below. We would be very grateful for some input into this. I fear we have misled many customers with our reports when we applied these settings in previous projects. Kind regards, Oliver
  2. Dear Martin, Many thanks for such a positive reply! Yes, I think you've distilled it down to what we would hope to see. Exactly. I have attached the technical notes from SMA and SolarEdge which give examples of how manufacturers are allowing this functionality to be configured. Whilst we don't expect PVSol to replicate this functionality fully, initially having a facility to at least load shift from the defined peak hours would be fantastic. Yes - the from-grid tariff in PV Sol already gives us the ability to set the From-grid Tariff periods, so I would expect we should be able to simply assign from-grid charging hours to these and schedule which months in the year this mode should apply. Normally we would never program from-grid charging during the sunnier months as it would significantly reduce the battery's capacity for storing the surplus energy from the solar PV array. Kind regards, Oliver SMA SmartHome_Time-of-use-TI-en-10.pdf storedge_charge_discharge_profile_programming.pdf
  3. Is there any chance you are working on further developing the battery discharge/utilisation modes? When we simulate systems with a time-of-use tariff we would like to "program" the battery to discharge over expensive tariff periods as a priority in order to best capitalise on the stored electricity. Also, are there plans to improve the charging strategies to enable from-grid (AC) charging? Most battery systems we install have this feature and we would like to set AC charging in the winter during the off-peak tariff in the software simulation. Many thanks!
  4. The from-grid tariff facility in new PV*SOL Premium 2016 is too simple to be truly useful. It is becoming increasingly important when we model PV systems to calculate the potential savings on customer's billed usage. Most of our commercial customers are on time-of-use metering and in the previous PV*SOL Expert we could easily input these tariffs. I feel like the software has been impaired by removing this functionality. Are there any plans to reintroduce this feature? Now we are designing storage solutions, and this can have an even bigger impact on the sizing and cost-effectiveness projections. With the tariff data we could also predict good charging strategies for battery systems and interpret this information when configuring the charge controller. Also, am I right that there is now no way to import and export individual database entries between copies of PV*SOL Premium? In PV*SOL Expert we would update our library of product, tariff or consumption profiles onto our 4 licensed computers to ensure all our systems were all in sync and reduce data entry time. Is this facility available any other way?
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