Restricting Power Export
One of the major expenses incurred when installing commercial scale PV systems over 16A per phase can be the cost to upgrade the grid infrastructure to accommodate the increased power flowing from the array the grid. When installing a lot of PV onto a roof, the DNO (Distribution Network Operator) has to ensure that the cables and transformers are able to deal with whatever energy the PV system is going to export.
However, in many cases such large PV systems are installed on premises that normally have high levels of self-consumption such as a factory. Where a business consumes a lot of electricity during daytime hours, then most or all of the electricity being produced will be consumed directly on site with very little being exported. Only on dormant days such as weekends and bank holidays is there the potential that all the power generation will end up exported onto the grid and it is this eventuality that the DNO has to take into account.
Therefore, it may be sensible to agree with the DNO that no more than a pre-determined amount of electricity can ever be exported onto the grid. This is a mutually beneficial arrangement, because the DNO doesn’t have to worry about large amounts of electricity entering the grid on weekends and bank holidays (when it is least needed) and the client does not have to pay to upgrade the grid to cope with such large currents.
Restricting The Amount You Export
Export restriction is now a requirement in Germany where systems are limited in only being able to export 70% of the generation capacity. Global-leading PV inverter manufacturers SMA have developed some sophisticated ways of managing this. By combining the SMA Sunny Home Energy Manager and the SMA Energy Meter, the amount of electricity being exported can be measured. The Active Power Feed-In value can be programmed in, for example to 4kW and if the balance between generation and self-consumption reaches a point where the system might export more than this value, then the Home Energy Manager can tell the inverters to de-rate and turn DOWN their production. This is more sophisticated than some other export limitation devices currently available which simply turn OFF the inverters.
Smart Energy Management
Take the example of a dairy on a single-phase supply which often has to supplement the electricity it imports from the grid by using a diesel generator. An installer makes an offer to install a 100kW Solar PV system. The DNO assesses the situation and determines that in order to cope with all the electricity being produced the grid will have to be upgraded to 3-phase and heavy costs need to be incurred. However, the energy consumption at the dairy is normally so high that most of the electricity won’t go onto the grid at all. In this case, the installer could come to an agreement with the DNO in which the Home Energy Manager is installed and programmed to limit the export to only 30kW. Most of the time the system will be producing 200kW and using that electricity on site. However, on a few days a year perhaps the dairy has to shut down for whatever reason, so in this case the Home Energy Manager will turn the 200kW right down to 30kW. The DNO is happy, because the integrity of the grid is ensured and the client is happy because now he only needs to pay to upgrade the grid for a 30kW system.
It's good to talk...
The financial savings of such a set-up can be significant. This system has the potential to open up commercial PV systems that ordinarily would not be viable because of prohibitive DNO costs and potential stress to the grid. Such systems also lead towards a more harmonious integration of renewable energy into the grid and a better relationship between clients and the DNO.
To determine whether such an application is feasible or not requires a good analysis of the energy consumption of the site and an early conversation with the DNO.
Get in touch with us here at Watt Energy Saver or by using our Contact Form by providing some information about your project. Our engineers will be very happy to help you start this dialogue with your local DNO for any potential commercial PV installation.
One of the major expenses incurred when installing commercial scale PV systems over 16A per phase can be the cost to upgrade the grid infrastructure to accommodate the increased power flowing from the array the grid. When installing a lot of PV onto a roof, the DNO (Distribution Network Operator) has to ensure that the cables and transformers are able to deal with whatever energy the PV system is going to export.
However, in many cases such large PV systems are installed on premises that normally have high levels of self-consumption such as a factory. Where a business consumes a lot of electricity during daytime hours, then most or all of the electricity being produced will be consumed directly on site with very little being exported. Only on dormant days such as weekends and bank holidays is there the potential that all the power generation will end up exported onto the grid and it is this eventuality that the DNO has to take into account.
Therefore, it may be sensible to agree with the DNO that no more than a pre-determined amount of electricity can ever be exported onto the grid. This is a mutually beneficial arrangement, because the DNO doesn’t have to worry about large amounts of electricity entering the grid on weekends and bank holidays (when it is least needed) and the client does not have to pay to upgrade the grid to cope with such large currents.
Restricting The Amount You Export
Export restriction is now a requirement in Germany where systems are limited in only being able to export 70% of the generation capacity. Global-leading PV inverter manufacturers SMA have developed some sophisticated ways of managing this. By combining the SMA Sunny Home Energy Manager and the SMA Energy Meter, the amount of electricity being exported can be measured. The Active Power Feed-In value can be programmed in, for example to 4kW and if the balance between generation and self-consumption reaches a point where the system might export more than this value, then the Home Energy Manager can tell the inverters to de-rate and turn DOWN their production. This is more sophisticated than some other export limitation devices currently available which simply turn OFF the inverters.
Smart Energy Management
Take the example of a dairy on a single-phase supply which often has to supplement the electricity it imports from the grid by using a diesel generator. An installer makes an offer to install a 100kW Solar PV system. The DNO assesses the situation and determines that in order to cope with all the electricity being produced the grid will have to be upgraded to 3-phase and heavy costs need to be incurred. However, the energy consumption at the dairy is normally so high that most of the electricity won’t go onto the grid at all. In this case, the installer could come to an agreement with the DNO in which the Home Energy Manager is installed and programmed to limit the export to only 30kW. Most of the time the system will be producing 200kW and using that electricity on site. However, on a few days a year perhaps the dairy has to shut down for whatever reason, so in this case the Home Energy Manager will turn the 200kW right down to 30kW. The DNO is happy, because the integrity of the grid is ensured and the client is happy because now he only needs to pay to upgrade the grid for a 30kW system.
It's good to talk...
The financial savings of such a set-up can be significant. This system has the potential to open up commercial PV systems that ordinarily would not be viable because of prohibitive DNO costs and potential stress to the grid. Such systems also lead towards a more harmonious integration of renewable energy into the grid and a better relationship between clients and the DNO.
To determine whether such an application is feasible or not requires a good analysis of the energy consumption of the site and an early conversation with the DNO.
Get in touch with us here at Watt Energy Saver or by using our Contact Form by providing some information about your project. Our engineers will be very happy to help you start this dialogue with your local DNO for any potential commercial PV installation.
