HOMER Knowledge Base
Resilience and Grid Outages in HOMER Grid
Product: HOMER Grid 1.5.2
What does "resilience" mean in HOMER Grid? How do I model grid outages in HOMER Grid?
Resilience, in the most general sense, is the capacity to recover quickly from difficulties. In the case of HOMER Grid, we are referring to the ability of a design to continue electrical service when there is a major utility disruption. HOMER Grid helps you to design the distributed energy system that can serve the required loads, even when the utility grid fails. Technologies such as solar PV, batteries, wind, generators, and combined heat and power systems can all improve a facility's resilience.
Resilience is particularly important when you have electrical loads that you do not want to disrupt. Facilities that provide emergency services, data centers, critical manufacturing plants, hospitals are all common locations where resilience is an important part of the design. However, resilience can be important anywhere that you want or need reliable power. It has been an increasingly important consideration in emergency planning for natural events that disrupt power such as storms and earthquakes, or even human-caused events such as terrorism or war. HOMER Grid can help you to design a system that maintains electricity during these events.
To model resilience in HOMER Grid, you have to specify the characteristics of the utility outage, the loads that you want to serve, and the equipment you would like to consider.
You can specify the outage characteristics in the Resilience menu in HOMER Grid. You may specify the length of the outage, when it starts, and the yearly frequency that it occurs. The image below shows how to find the Resilience menu to specify the outage characteristics.
You also need to specify the loads that you serve. HOMER Grid includes the ability to specify both critical and non-critical loads. A critical load will be served even if there is a utility outage, whereas a non-critical load will only be served when there is normal utility operation. Non-critical loads are not served when the utility is in an outage.
Finally, you need to specify the components that you would like to consider in your design. A generator is an important piece of equipment for ensuring a resilient electrical supply. To ensure that you can "ride-through" a utility outage, you will need to specify a generator that is capable of serving the critical loads. The generator should be sized to be larger than the peak power (i.e. kW) of the critical load. You should also consider adding solar PV or wind to reduce fuel usage during the outage, and storage to improve the operation of the generator and the integration of renewable solar and wind generation.
HOMER Grid will select a design that most cost-effectively provides resilient electricity for your specified electrical loads. To do this, it simulates the performance of the system both with and without the utility outage. This allows you to see the capability of the system design during normal operation, compared against its ability to continue to service the critical load when the utility is out. In this way, you can understand both how the system improves the economics, and how it improves resiliency in the face of major utility disruptions.
In the screenshot below, taken from the "PV-Battery Out-patient Client Resilience HELCO USA" sample file included with HOMER Grid, you can see that drop-down menu that lets you how the system operates both with and without the utility outages. In this case, the design serves a 10-day outage, but the generator only has to operate one hour during the 240-hour outage. Solar PV and battery work together to reduce the reliance on diesel.
What does "resilience" mean in HOMER Grid? How do I model grid outages in HOMER Grid?
Resilience, in the most general sense, is the capacity to recover quickly from difficulties. In the case of HOMER Grid, we are referring to the ability of a design to continue electrical service when there is a major utility disruption. HOMER Grid helps you to design the distributed energy system that can serve the required loads, even when the utility grid fails. Technologies such as solar PV, batteries, wind, generators, and combined heat and power systems can all improve a facility's resilience.
Resilience is particularly important when you have electrical loads that you do not want to disrupt. Facilities that provide emergency services, data centers, critical manufacturing plants, hospitals are all common locations where resilience is an important part of the design. However, resilience can be important anywhere that you want or need reliable power. It has been an increasingly important consideration in emergency planning for natural events that disrupt power such as storms and earthquakes, or even human-caused events such as terrorism or war. HOMER Grid can help you to design a system that maintains electricity during these events.
To model resilience in HOMER Grid, you have to specify the characteristics of the utility outage, the loads that you want to serve, and the equipment you would like to consider.
You can specify the outage characteristics in the Resilience menu in HOMER Grid. You may specify the length of the outage, when it starts, and the yearly frequency that it occurs. The image below shows how to find the Resilience menu to specify the outage characteristics.
You also need to specify the loads that you serve. HOMER Grid includes the ability to specify both critical and non-critical loads. A critical load will be served even if there is a utility outage, whereas a non-critical load will only be served when there is normal utility operation. Non-critical loads are not served when the utility is in an outage.
Finally, you need to specify the components that you would like to consider in your design. A generator is an important piece of equipment for ensuring a resilient electrical supply. To ensure that you can "ride-through" a utility outage, you will need to specify a generator that is capable of serving the critical loads. The generator should be sized to be larger than the peak power (i.e. kW) of the critical load. You should also consider adding solar PV or wind to reduce fuel usage during the outage, and storage to improve the operation of the generator and the integration of renewable solar and wind generation.
HOMER Grid will select a design that most cost-effectively provides resilient electricity for your specified electrical loads. To do this, it simulates the performance of the system both with and without the utility outage. This allows you to see the capability of the system design during normal operation, compared against its ability to continue to service the critical load when the utility is out. In this way, you can understand both how the system improves the economics, and how it improves resiliency in the face of major utility disruptions.
In the screenshot below, taken from the "PV-Battery Out-patient Client Resilience HELCO USA" sample file included with HOMER Grid, you can see that drop-down menu that lets you how the system operates both with and without the utility outages. In this case, the design serves a 10-day outage, but the generator only has to operate one hour during the 240-hour outage. Solar PV and battery work together to reduce the reliance on diesel.