How can wood store solar energy at night?

Wood that acts like a solar heat battery

Researchers demonstrated a method for generating solar power after dark by using reengineered balsa wood to store sunlight as heat. The core idea is that instead of relying on typical solar panels—which stop producing electricity once darkness falls—the stored energy can be released later as usable power.

The approach is framed as a workaround to a major limitation of solar energy: the supply is inherently time-dependent. By turning a piece of low-cost, lightweight wood into an energy-storing material, the system can absorb solar energy during the day and then release it when it’s no longer directly available.

What the experiment showed

• Daytime charging: the material captures solar energy and converts it into stored thermal energy.
• Night-time discharge: once the environment cools and there’s no sunlight, the stored heat can be used to drive a power-generation pathway.

This matters because thermal storage is one of the most promising ways to make solar electricity more dispatchable. Many existing solar-plus-storage systems rely on engineered salts, molten materials, or other specialized hardware; using a modified natural material like balsa wood could potentially reduce costs and simplify deployment.

Why it could matter for clean energy

Solar power is abundant, but grid operators need power on demand. A low-cost, heat-storing material that can be charged daily and discharged at night could help:

• smooth out daily fluctuations in electricity supply,
• reduce reliance on fossil peaker plants,
• and expand solar’s usefulness in places where night-time demand is high.

No details were provided in the story excerpt about efficiency, durability, or scaling limits, but the proof-of-concept demonstrates a pathway to “charge in, generate later” using a surprisingly simple substrate.