SMA Solar Technology AG September 2013 Technical benefits of String Inverter Technology Mark Ryder

SMA Solar Technology AG 1 String inverter concept Benefits of String inverters Agenda 2 3 Low light conditions 2 4 Shading Management 5 Derating curves 6 Communication & Monitoring 7 Summary

SMA Solar Technology AG String inverter concept and applications 3 Residential and small commercial sites:  Small string inverters (usually single phase), the entire PV array can be just one string Medium-size systems (50kW-250kW or more): commercial roofs, warehouses, farms...  Decentralised designs using three or four strings connected to the inverter (mainly three-phase) With different oriented sub-arrays or shading issues, the string inverter concept enables better power-related adaption to the irradiance conditions

SMA Solar Technology AG 1 String inverter concept Benefits of String inverters Agenda 2 3 Low light conditions 4 4 Shading Management 5 Derating curves 6 Communication & Monitoring 7 Summary

SMA Solar Technology AG  Easy transport and installation  Wide range of power classes available: Single phase Three phases  Flexible designs (different orientation and inclination): 2xMPPT's, OptiTrac...  High Efficiency  Easy maintenance  Reliable  Easy monitoring Benefits of String inverters 5

SMA Solar Technology AG 1 String inverter concept Benefits of String inverters Agenda 2 3 Low light conditions 6 4 Shading Management 5 Derating curves 6 Communication & Monitoring 7 Summary

SMA Solar Technology AG Low light conditions 7  In countries with low levels of radiation, such as the UK, with less than 1250kWh/m2 year, the efficiency curve for lower power becomes more important.

SMA Solar Technology AG 1 String inverter concept Benefits of String inverters Agenda 2 3 Low light conditions 8 4 Shading Management 5 Derating curves 6 Communication & Monitoring 7 Summary

SMA Solar Technology AG Shading Management 9  It is not always possible to prevent shadows on PV plants.  The loss must be minimized already in the planning phase.  Influential factors:  arrangement of the PV modules  connection of PV modules  the choice of the right inverter Selecting the system connection Severe shading: operate shaded and unshaded PV modules separately. ‒ No parallel connection of strings with different irradiation 2xMPP Tracker inverters ‒ The MPP tracking concept of the inverter is decisive to maximize the energy yield. Improved MPP trackers can find the optimum operational point, the global MPP: SMA OptiTrac Global Peak

SMA Solar Technology AG 1 String inverter concept Benefits of String inverters Agenda 2 3 Low light conditions 10 4 Shading Management 5 Derating curves 6 Communication & Monitoring 7 Summary

SMA Solar Technology AG Derating curves 11  The inverter reduces its power to protect components from overheating.  The correct design of a PV plant must not completely exclude derating.  High temperatures and overheating can occur when inverters are mounted in commercial closed plant rooms with low ventilation Best practices:  Install the inverters in cool locations  Sufficient air exchange  Not under direct sunlight  Minimum clearance between inverters  Select an inverter with good derating curves

SMA Solar Technology AG 1 String inverter concept Benefits of String inverters Agenda 2 3 Low light conditions 12 4 Shading Management 5 Derating curves 6 Communication & Monitoring 7 Summary

SMA Solar Technology AG Communication & Monitoring 13  Monitoring ensures that failures or faults are quickly detected  For medium and large size systems a data logger is required  New technologies allow faster communications (Webconnect/Speedwire)  With internet-base monitoring systems, a service provider takes over the evaluation of the operating data.

SMA Solar Technology AG 1 String inverter concept Benefits of String inverters Agenda 2 3 Low light conditions 14 4 Shading Management 5 Derating curves 6 Communication & Monitoring 7 Summary – SMA Case study

SMA Solar Technology AG Summary 15  Wide range of string inverters depending on the application:  For complicated commercial roofs:  Shading issues, difficult configurations: standard Sunny Tripowers (with 2xMPP Trackers and OptiTrac Global Peak)  Easy and simple commercial roofs (cost-effective systems): Sunny Tripowers- project version  Useful for East-West configurations too: polystring concept

SMA Solar Technology AG SMA solution for commercial roofs: Unique Project Performance Package 16  Sunny Tripower TLEE PROJECT – gains highest yields  Cutting edge high speed communication – optimises the plant control and gives full visibility INVERTER COMMUNICATION  Commissioning package – secures your investment  Remote Service – reduces transaction cost  99% Availability Guarantee – insures your ROI SERVICE >> This is unique in the market and only offered by SMA.

SMA Solar Technology AG SMA Case study 17 Sunny Tripower inverters complete your projects with the all the benefits of string inverters:  High efficiency (over 98%) under low light conditions  OptiTrac Global Peak and 2xMMP trackers for shading management  Good derating curves  Easy and fast communication & monitoring with SMA devices  Reliable and easy maintenance

SMA Solar Technology AG THANKS FOR YOUR ATTENTION 18