Farm Energy Planner

The farm had a big decision to make. The old diesel generator was rattling, smoking and nearly worn out.

"We need a new way to power the farm," said Suzy. "The water pump, the dairy and the house all need electricity."

Little Thunder spread out a giant chart with twenty-four hours across the bottom. "Then we plan it, hour by hour."

Spike sorted a pile of picture cards first. "Coal, oil and gas are non-renewable. They take millions of years to form, and once they're gone, they're gone. Sun, wind and water are renewable. They keep coming back."

"So we choose renewable," said Little Thunder. "Easy!"

Suzy smiled. "Not quite. The sun only shines in the daytime."

They looked at the chart. The dairy needed lots of power at five in the morning for milking. The pump ran all through the day. The house needed lights and cooking at night.

"Solar panels make the most power at midday," said Spike, drawing a big hill shape across the middle of the chart. "But nothing at five in the morning, and nothing at night."

"What about wind?" asked Little Thunder.

Suzy checked the weather records. "Our hill gets wind most nights."

"Then we need both," said Spike. "And batteries to store extra power for later."

They followed the energy as it changed form. Sunlight became electricity in the panels. Wind turned the turbine's blades, and that movement became electricity too. The batteries stored it as chemical energy, then gave it back as electricity when the house lights switched on.

But there was a budget. Each solar panel cost money, each turbine cost more, and batteries cost the most of all.

They tried different plans on the chart. Too few panels, and the pump stopped at three o'clock. Too many batteries, and they ran out of money. Finally they found it: twelve panels, one turbine and two batteries.

The chart showed power all day and all night.

That evening, the house lights glowed while the turbine turned on the hill.

"No smoke, no rattle," said Little Thunder happily. "Just sun and wind."