What is energy storage?
Energy storage is the practice of retaining generated energy for use at a later time. For buildings, this usually concerns electricity (batteries), heat (boilers or buffer tanks) or seasonal storage (ground source). With storage, supply and demand can be better aligned.
Why store energy?
Solar panels generate electricity at the “wrong” time: during the day when many homes need little, and not at all in the evening when demand peaks. Energy storage bridges this gap.
Other drivers:
- Decreasing feed-in tariffs — selling back to the grid becomes less profitable
- Grid congestion — the electricity network is overloaded in many areas
- High gas and electricity prices — your own energy becomes more valuable
- Self-sufficiency — less dependence on suppliers and grid
Applications
Electrical storage
- Home battery — lithium-ion battery of 5–20 kWh, linked to solar panels
- Vehicle-to-home (V2H/V2G) — electric car charges and discharges to home or grid
- Lead-acid batteries — cheaper but heavier and shorter life
- Community batteries — collective storage at neighbourhood level
Thermal storage
- Hot-water buffer — insulated tank that stores hot water for heating or DHW
- Boiler — domestic hot water, including electric solar boilers
- PCM (phase change materials) — salt hydrates that store heat via phase transition
- Seasonal storage — geothermal via ATES (aquifer thermal energy storage)
Mechanical and chemical storage
- Pumped hydro — water pumped uphill, later released through turbines
- Flywheel — short-term electrical storage in a spinning mass
- Hydrogen — surplus electricity converted to H₂ for long-term storage
Considerations
- Fire safety — lithium batteries require a suitable location
- Lifespan — batteries have a limited number of charge cycles
- Payback time — as feed-in tariffs fall, batteries pay off faster
- Permits — larger installations may require a building permit
Related terms
- Geothermal energy
- Heat pump
- Solar panels
- Energy-efficient home
- Aquifer
Want to learn more about construction terms? Visit our knowledge base at fredsdiyplans.com.