Consider the following : 1. Battery storage 2. Biomass generators 3. Fuel cells 4. Rooftop solar photovoltaic units How many of the above are considered "Distributed Energy Resources" ?

Describes pumped storage as a facility that 'works like a battery' by storing generated electricity for later use, giving an example of large-scale energy storage.

A student can contrast this large, centralized storage example with smaller battery units to ask whether scale or location distinguishes DER from grid-scale storage.

Defines batteries as compact, portable sources of electrical energy used in many devices, indicating batteries exist at small, distributed scales.

Combine this with the idea that DER are small/local resources to infer that small, co‑located battery systems (e.g., home or device batteries) fit the distributed pattern.

Notes rechargeable batteries range from small device batteries to bigger batteries that run inverters or drive electric vehicles, showing a spectrum of sizes and applications.

A student can extend this to consider that mid‑to‑small batteries used with inverters or EVs can be deployed at customer sites and thus resemble DER deployment.

Lists 'dry batteries' among ways electricity can be generated/used, treating batteries as part of the electricity ecosystem rather than solely large central plants.

Use this to support the view that batteries are a form of electrical resource which, when sited locally, could be classified alongside other distributed resources.

Explains modern rechargeable (Li‑ion) batteries' widespread use and importance for shifting to environmentally friendly power, implying technological readiness for grid applications.

A student could infer that because these batteries are increasingly used and scalable, they can serve distributed grid functions (storage/backup), supporting their candidacy as DER.