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Five considerations for designing DERs with increased energy autonomy


Lauren Flanagan, Executive President and Co-Founder of Sesame Solar, discusses key considerations that simplify the process of designing Distributed Energy Resources (DERs) that create energy self-sufficiency.

energy autonomy

Lauren Flanagan, Executive President and Co-Founder of Sesame Solar

Distributed Energy Resources (RED) are dramatically changing the way energy is produced, stored and distributed. Ideally, they are mobile and rapidly deployable to provide essential energy and resources when and where needed, especially after extreme weather events or emergencies. These DERs create energy autonomy by ensuring energy independence and self-sufficiency.

DERs can have a profound impact by providing extended periods of energy self-sufficiency when the grid is down or unavailable. Combining renewable energy sources such as solar and battery storage with backup power from hydrogen fuel cells and wind turbines to achieve days, weeks or months of uninterrupted power can be complex and difficult. , especially if the DERs must be rapidly deployable. Here are five considerations to simplify the process.

1. Define the use case

The first consideration is how the DER will be used. By determining how the DER unit will be used, you can then specify the type, size, and additional power sources that will need to be integrated to meet its power and distribution needs.

Energy autonomy

Sesame Solar DER designed for Cox Communications. Photo by Namit Jhanwar

Questions to ask:

  • Will it mainly be used to export electricity from renewable energy sources or additional resources such as drinking water, telecommunications, medical assistance, offices, electric vehicle charging, Refrigeration or personal care such as toilets, showers, laundry facilities or kitchen facilities will be required?
  • When and where will the DER be deployed?
  • Will it be used only for network outages and emergencies or on an ongoing basis?
  • Will it be necessary to regroup DERs, for example, in a first responder base camp or to support evacuees after extreme weather events?
  • What is the required lifecycle of the DER?
  • Who will transport and operate the DERs?
  • What skills are required of operators and how will they be trained?
2. Define mobility and footprint

Typically, a DER is used intermittently during network outages or emergencies. DERs used primarily for the export of electricity are constructed from smaller 10-14 foot twin-axle trailers and towed by a three-quarter-ton truck. DERs that incorporate other resources, such as an emergency office or telecommunications center, are typically built from a larger 16 to 20 foot twin-axle trailer and towed by a truck with a length of tonne.

Mobile DERs require the incorporation of lightweight materials and components such as flexible solar panels, lithium-ion battery storage, proton exchange membrane (PEM) hydrogen fuel cells, and / or small vertical wind turbines. Special design consideration should be given to the Combined Gross Weight Rating (GCWR) of the available transport equipment.

DERs used permanently in a semi-permanent location must be mobile in the event of an emergency or changes in location requirements. They are built from ISO shipping containers (10, 20 or 40 feet) and are towed on a flatbed trailer, which must meet CDL requirements.

Larger, containerized DERs are less weight sensitive, allow for a larger solar panel and battery storage to provide export power. They can incorporate more features, such as electric vehicle charging, a full medical clinic, toilets, showers, and kitchen facilities. Heavier, more energy-efficient alkaline hydrogen fuel cells can be used for back-up power, and larger wind turbines can be integrated to provide export power from 100% renewable sources.

Energy autonomy

Sesame Solar DER with communications and Wi-Fi services. Photo by Namit Jhanwar

3. System sizing

Once the use case, location, mobility and footprint are defined, the energy needs can be sized. The DER footprint usually determines the size of the solar panel. Sesame Solar’s patent-pending DER nanorods use a retractable solar panel to expand power production into a smaller footprint.

The battery storage system should match solar production with additional storage capacity to accommodate inclement weather or smoke from forest fires. However, it cannot be much larger than what can be recharged by solar and backup power systems – hydrogen fuel cells and wind turbines, the power of which must also be matched to the capacity of the system. battery storage. The grouped DERs share energy, potentially reducing the individual energy production and storage needs of the DERs. Component life cycles should match the DER’s longevity goals.

Questions to ask:

  • What is the expected peak energy consumption?
  • What is the average energy consumption?
  • How many days or weeks of uninterrupted feeding are required?
  • How many hours of sunshine are available at the desired location?
4. Design for energy autonomy

Extended power autonomy DERs typically require multiple power inputs and a power management system to seamlessly switch between them. Sesame Solar’s nanogrid DERs include a variety of essential services in addition to exporting electricity from several renewable energy inputs. AC export power and essential services are provided by lithium ferrophosphate (LFP) batteries, which contain no cobalt and have lower thermal runaway. Solar power is the primary energy source for LFP storage in Sesame Solar nano-arrays and hydrogen fuel cells provide backup power.

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Sesame Solar mobile, turnkey nanogrid DER. Photo by Namit Jhanwar

These nanogrids produce green hydrogen from electrolysis and it is stored in low compression, non-pyrophoric semiconductor tanks, supplying hydrogen to the fuel cell. When LFP batteries are approximately 35% depleted, the necessary days of energy autonomy are created by matching the hours of hydrogen storage to the rate of admission of hydrogen fuel cells and the rate of hydrogen production to from electrolysis, while the solar panel replenishes the battery.

The use case, the energy management system and the battery storage capacity determine the optimal parameters for switching from solar energy to hydrogen energy and vice versa. Small wind turbines can provide filling renewable energy in areas where there is sufficient wind.

5. Design for rapid deployment

DERs that are shipped out of the box with a fully integrated renewable energy system are quickly deployable and quickly configured to deal with sudden grid outages or emergencies. Ease of use comes from the complete design of the DER system, process automation, integration of hazardous materials and safety, management of consumables (water and electrolytes), remote software guidance , system health monitoring applications, augmented reality for training and field support, and regular maintenance to keep the DER performing throughout its lifespan.

Careful consideration of these considerations produces a DER with power drawn from multiple renewable energy sources, providing essential services when and where they are needed and for as long as they are needed.

Lauren Flanagan is Executive President and Co-Founder of Sesame Solar where she leads strategic initiatives.

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