Pow Charg er Fault EMMA STORAGE WITH AQUION ENERGY BATTERIES AND HOT WATER CLEAN GREEN SAFE STORAGE Upperlands Coffee: 4kWp PV, 5kWp Wind with 25kWh EMMA Battery Storage with 3kW of EMMA Heat Storage Solar Panels Inverter house Grid EMMA STORAGE CONTROL e Invert Wind Turbine MAIN SYSTEM COMPONENTS -PV Panels Peak Output = 4kWp -Wind Turbine Peak Output = Evance 5kWp -Inverter/Charger = Studer XTM 8000-48 -Battery Storage = 12 Aquion S20's combined 25kWh -Control System = EMMA Storage Controller -On-Offgrid = Manual Switchover -Heating = EMMA Power Throttle 3kWp EMMA POWER THROTTLE Upperlands Coffee Company is based on the grounds of a homely farm house which has a 4kWp south facing PV array coupled with a 5kW Evance wind turbine. The client had added an Aquion M- Line stack with a self-consumption system to capture the excess production from the renewables on site. The generation declined dramatically after the install of the self-consumption system. Having met the EMMA team at shows in both the UK and Ireland the client asked to see an EMMA self-consumption system up and running to see if it could rectify his low production. Figure 1. PV South facing 4kWp On seeing the EMMA system first hand working exactly as it should with a combined storage of battery and heat the client asked to move forward with swapping out the old system (not supplied by the EMMA team) for the new EMMA system. Quick install With the Batteries in place and much of the wiring already in place from the previous system the EMMA Storage System was installed in less than 2 hours. Figure 2. 5kWp Evance Wind Turbine Versatility The previous system was supposed to provide heating but due to wireless transmission constraints this part of the previous
system also failed to meet the client s needs. With the EMMA Power Throttle there is always a method to make it reach either by wireless extenders or just a good old fashioned cable. In this case an existing Ethernet cable made the 30m connection allowing a second monitor to run in the clients which controls the Throttle in the hot press just down the hall. Visibility - With the addition of the second monitor which controls the heating the client can see everything that happens with his power and his heating at a glance with the EMMA intuitive touch screen display. The screen also allows the client to set his full hot water heating schedule for times of low renewable production just like having a normal timer on your oil or immersion. The client also has the option to boost the heat at the touch of a button or via the app on his smartphone. Temperature feedback comes as standard with all Figure 4. New EMMA Control EMMA Heat Storage units giving the client visibility on when there is enough hot water to have a shower or have a bath or just wash the dishes. This also promotes efficient heating of the cylinder by applying an import cut off temperature so the tank only heats to the required temperature rather than when the stat cuts out on the tank. A renewable cutoff temperature is also used and is normally set much higher to capture as much of the free energy into the tank as possible. Operation The EMMA Storage System captures the exportable power and stores it in a 25kWh Aquion Aspen M-Line battery bank. The charger can reach up to 7kWp Figure 3. New Power Throttle fitting snugly in the hot press depending on the state of charge of the batteries but the renewables generally don t reach this together and is evident from the monitoring that EMMA has offered to date. As the batteries charge up they accept less current resulting in the charger not being able to put the full production into the battery bank but the EMMA Heat storage kicks in as the charge decline and puts any surplus power into the hot water cylinder harnessing all power produced on site. Storage - Using the EMMA Storage System the client stores most of the exportable power in a 25kWh Aquion Aspen M-Line battery bank. The storage medium is a critical aspect to all EMMA systems as years of monitoring data has shown that where a grid paralleled battery is used it will have to cope with multi cycling at a partial state of charge and be robust enough to handle repeated rapid swings from charging to discharging. Along with the abuse that nature will throw at any self consumption system there is also the physical attributes of the install of such a battery to consider. As this system is in a live working environment where vacuum packing machines, roasters, angle grinders, drills, trollies and vehicles are all part of the daily coffee grind it is imperative that the batteries are safe for the people around them. For example they cannot stifle the air with hazardous fumes or combust in some way if a forklift accidently bumps into them or require regular maintenance. Figure 5. Aquion Aspen M-line 25kWh used on the site. 2
Why Aquion? - The client chose the Aquion battery prior to EMMA being part of the install but the following were the main items that led the client down the path of Aquion : Unparalleled Safety Not flammable, explosive, or corrosive No dangerous or toxic components Inherently safe chemistry Sustainable Environmentally benign materials No corrosive acids or noxious fumes Suitable for broad deployment globally Simple Low acquisition costs (, /kwh) Better value than lead acid or li-ion No active management required Little/no thermal management No regular maintenance Industry-leading total cost of ownership Figure 6. EMMA Storage retrofit with existing generation and renewables. Resilient Very high cycle life at 100% depth of discharge Extremely abuse tolerant Ability to stand at partial state of charge Wide operating temperature range Self-balancing Minimal degradation EMMA helps the Client meet their objective Figure 7. Full generation set of Solar PV, Solar Thermal and Wind Turbine. The Clients objective was to reduce dependency on the electricity grid and to displace fossil fuel use where possible using renewables. The renewable power produced is displaced via EMMA Storage control to: 3 Immediate demands (Lights, Computers, Electric AGA) Storage to Aquion Battery Heating hot water Combined charging of 25kWh Nissan Electric Vehicle from renewables and Aquion battery Vacuum Packer supplied from Renewables and Aquion Battery controlled by EMMA Coffee Bean Roaster supplied from Renewables and Aquion Battery controlled by EMMA In times of low renewable generation and empty battery, the balance of the required power will be supplemented by the grid
EMMA makes Auto-generation Work With the EMMA Storage System running for some months it has proved its promise of utilizing the battery to its fullest and dramatically reducing and in cases eliminating the import from the grid. The proof to back it up is plain to see for the client in the logs that the EMMA provides online with three-minute averaged data. The Techie bits Observation 1: Part of the client s objective was to minimise export to the grid so it could be consumed on site. Using the EMMA Monitoring system, it is easy to scroll through the graphs and pick out what you want to see by disabling certain trends or legends. In Figure 8 below with just the Export in blue and Generation in green trend lines enabled it is clear that the EMMA Storage System is minimizing the export to the grid significantly. 4 Figure 8. Snapshot of 10 days production with close to zero export. Holding the power from flowing back to the grid means it must be satisfying the loads and charging the battery. Observation 2: Taking a closer look at the 28th and 29th of September it is obvious that there is significant combined generation from both the PV panels and the Wind Turbine with peaks of generation reaching up to 6.5kWp. This energy production is quite volatile as the Wind Turbine provides a spikey output ontop of the solar PV production. During this period the EMMA Storage system is working hard to supply the immediate loads charge the battery invert from the battery when production drops, adapt for large loads such as the vacuum packer turning on and Figure 9. Very spikey generation with no import or export. off by inverting and
charging by just the right amount to keep the import and export null. Let s take a look at how hard the system is actually working: Observation 3: Using the exact same timespan from Figure 9 but this time we look at the Studer Inverter/Charger controlled by the EMMA Storage system inverting and charging repeatedly to and from the battery to minimize import and export. Figure 10. Multi cycling of battery to hold import and export at zero. In Figure 10 above the EMMA Storage system shows the green trend line as charging when positive and inverting when negative. This shows the system in full operation swinging from charge to invert and back again over 120 times in the space of 34 hours. This is why the Aquion battery is an ideal candidate for a selfconsumption system as its strength is in the fact it is built to handle the hardship of partial state of charge on a continuous basis without degradation with multi-cycling at a significantly discharged level not impacting the life of the battery. While this 34-hour snapshot of months of similar operation justifies the choice of the Aquion it also highlights the sophisticated control the EMMA Storage provides with autonomous operation. During this period the client was: Charging an Electric Van Running a Coffee roaster Operating a Vacuum Packer Using an Angle Grinder Running multiple standard appliances at different times 5
At the same time the generation was ramping up and down vigorously with the EMMA Storage filling the battery with the excess and filling the void with the battery when there wasn t enough. In the client s words it s working like magic Observation 4: The autonomous operation is not confined to one 34-hour slot, it happens for long periods of time with the only drawback being the lack of renewables rather than the lack of storage in this case. In Figure 11 below 3 days and nights went by with the Solar PV supplying the site just by using the EMMA Storage with the Aquion battery to shift the power to when it was needed. The Solar PV bell curve is very evident in the charging during the day. There was no wind during this period so only the 4kWP PV system provided this power. Figure 11. c3 Days without grid requirement. Not to forget the heating: The EMMA Storage has heating included on this site as described earlier to capture the last few drops of power that might escape to the grid. While it doesn t happen very often on this site because the client also has solar thermal; the battery does sometimes get close to full charge and the heating will take over as the charge reduces. The client has a 1.5kW immersion in a 350L tank. During the plot in Figure 12 it is easy to see the power going to the tank with the purple trend line and the temperature increasing directly proportional to the power going into the tank with the broken red line. 6 Figure 12. Hot-water tank with temperature increasing.
Benefits The Client now has a working system with the benefit of: Figure 13. Nissan NV200 Electric Van 25kWh storage Monitoring the site to show from a client s perspective it is working as intended. Significantly reduced import and export basically filling the import with export using EMMA Storage Reduced consumption of Diesel by charging an electric van with renewables. Reduced consumption from oil by heating the house with an Electric Aga type cooker. Oil use reduced to 2 hours per day in winter. The stability of having the grid but can run off-grid in the case of a power cut with the flick of a switch with the renewables continuing to run and charge the batteries. Has the option to upgrade with further renewables without grid connecting them to boost production. Summary This installation consists of 12 Aquion AHI Batteries specifically chosen by the client for their clean, green and safety attributes coupled with their durability in diverse temperatures and abrasive environments with the ability to cope with multi partial charging and discharging. The site required a non-intrusive grid paralleled system with off grid operation ability. The only way to get the most out of your battery system is to make sure the renewables are always online and producing the maximum possible. The previous system installed at the site highlights that not all self-consumption systems are equal and the client realised this when OFGEM alerted him that his production had dropped dramatically since the first storage system had been installed. On installation of EMMA Storage, the renewables immediately resumed optimum production, optimum earnings, optimum use of storage leading to optimum savings. With the EMMA Storage the client had the following to say: When savings are being considered, they should be viewed not just as the electricity stored and saved. The savings need to be calculated including the reduction in other forms of energy being used. In this case the use of fossil fuel has been significantly reduced. Central heating oil purchases have been reduced by the installation of solar thermal units. Further savings are being made since the EMMA Storage system has been installed. Utilising stored renewable electricity in batteries is achieving a more satisfactory and cost effective consumption of the power generated. Batteries in this case means both the Aquion salt water battery and the Nissan vehicle fitted battery. Recharging the electric vehicle from renewable sources is now enhanced with the availability of 25kw from the EMMA Battery Storage System. Significant savings are made from zero diesel costs and zero road tax. Also as the Energy Storage System is a business expense Income tax implications can have a significant impact on total costs involved. EMMA Storage It works like magic. www.coolpowerproducts.com - www.aquionenergy.com - www.studer-innotech.com www.henboenergystorage.com 7