the EROEI of solar PV is lower with energy storage than without energystorage. Explain why.

The Energy Return on Energy Invested (EROEI) of solar photovoltaic (PV) systems is lower with energy storage than without energy storage due to several reasons:

1. Energy Conversion: When energy is stored, it often needs to be converted from one form to another. For example, the electricity produced by solar panels is converted into chemical energy in a battery during storage. This conversion process is not 100% efficient, meaning some energy is lost as heat.

2. Energy Storage: The process of storing energy itself consumes energy. For instance, charging a battery involves some energy loss. This is due to the internal resistance of the battery which generates heat during the charging process.

3. Energy Retrieval: When the stored energy is needed, it must be converted back into a usable form. For example, the chemical energy in a battery must be converted back into electrical energy. This conversion process also involves energy loss.

4. Equipment Manufacturing: The manufacturing of energy storage systems (like batteries) also requires energy. This includes the extraction of raw materials, transportation, assembly, and eventual disposal of the storage system. This energy cost is added to the total energy invested, thus reducing the EROEI.

5. Maintenance: Energy storage systems require maintenance which also consumes energy. This includes tasks like cooling of batteries to prevent overheating.

In contrast, a solar PV system without energy storage directly converts sunlight into electricity which can be used immediately, avoiding the energy losses associated with storage. Therefore, the EROEI of solar PV is lower with energy storage than without.