Alternative energy for your home: solar panels, small wind turbines, heat pumps

More and more households are putting solar panels on their roofs, especially where they can sell surplus power back to the grid. But many of these systems hide an unpleasant surprise: in a power cut, they switch off too. If what you want is independence in a crisis, not just a lower bill, the system has to be designed differently.

Solar: grid-tied, hybrid or off-grid

Type	How it works	In a power cut
Grid-tied	Panels power the house, surplus goes to the grid	Shuts down, for safety
Hybrid with battery	Like grid-tied, plus a battery and a backup circuit	Powers the loads on the backup circuit
Off-grid	No grid connection, everything runs through batteries	Works normally

For preparedness, the right choice for a house is a hybrid system with a battery and a backup (EPS) output. The electrician separates a sub-panel with the essential circuits (fridge, boiler, lighting, kitchen sockets, water pump), which the inverter powers from the battery and panels when the grid fails.

How big a battery

For the essentials, a house typically uses 3 to 6 kWh a day (fridge, boiler, lights, router, a few small appliances). A 5 to 10 kWh battery, together with the panels, can cover a day or two, even in cloudy weather. In winter, solar output drops sharply, so the battery matters more than the number of panels.

Small wind turbines

A turbine on the roof is an appealing idea, but few homes have the wind it needs: steady, at least 4 to 5 m/s, with no obstacles. In towns and most villages the wind is weak and turbulent, and small turbines produce little and make noise. They make sense only in open, exposed places, on hills or the coast, as a complement to solar, especially in winter.

Micro-hydro

If you have a stream with a steady flow and a drop on your land, a micro-turbine can produce power day and night. It’s a rare situation and usually needs water permits. For most people it isn’t an option.

Heat pumps

Heat pumps (air-to-water, air-to-air, ground source) heat a home very efficiently, but they need electricity. In an outage, they stop. Combined with a hybrid solar system and a battery, though, they’re one of the best long-term setups: the house is heated with locally produced energy and the battery covers short outages. For long winter outages, keep a heat source that doesn’t depend on electricity (a certified wood stove, for example). See heating without power.

What you can do in an apartment

In an apartment the options are limited, but not zero:

• a portable power station with a folding solar panel, put out on the balcony by day (see the power station guide);
• solar lanterns, charged in a window;
• a small solar charger for phones, in the go bag;
• a balcony solar kit with a battery, if your building and local rules allow it.

In short: what’s worth it, in order of priority

1. Solar lights and a solar phone charger: cheap and useful for anyone.
2. A power station with a folding panel: covers the essentials in an apartment.
3. For a house: a hybrid solar system with a battery and backup circuit, not just grid-tied.
4. Long term: a heat pump powered by your panels, with a backup heat source that doesn’t depend on electricity.