Solar panels are an infinite source of free energy while producing no pollution. During daylight hours every panel provides the maximum power level, 60kW. Generated power will increase/decrease linearly during dusk and dawn, and no power is produced at night. When placed, the Solar Panel takes up 9 spaces, in a 3x3 area.
As already stated, solar panels produce energy only during the day, but you are likely to want your factory running at night as well.
Accumulators are not the only way to work with solar energy. Sometimes it is more economical to just avoid consuming energy at night. For example, if you power a bunch of Electric mining drills and Electric furnaces to produce iron and copper plates, you could build more drills and furnaces than you actually need, and store the excess production during the day. At night you can shut down extractors and furnaces, and let your factory run with the stored plates. Instead of storing energy, you are storing what the energy is used for. The easiest way to achieve this is by connecting all your extractors and furnaces to a separate electric network with exactly enough solar panels to make them work during the day. The rest of your factory would be connected to a separate electric network, with other solar panels, and possibly accumulators and/or steam engines. Another way is to put your whole factory on the same electric network, but use a circuit network to monitor the charge level of your accumulators and shut down a sub-network with a power switch as soon as the accumulators charge goes below 90%. The same technique can be applied to your steam engines to enable them only when your accumulators are almost discharged. In both cases, an hysteresis can be used to avoid toggling on/off a whole part of the electric network at every tick (for example: when accumulator charge goes below 80% you shut down furnaces, but you enable them again only when accumulator charge is above 95%).
- It takes 23.8 solar panels to operate 1MW of factory and charge enough accumulators to sustain that 1MW through the night
- Ecology in factorio has many similitudes with the challenges of the energy transition in real life, where energy production is only one part of the problem, because renewable energy sources are usually intermittent. Consumption planning, and energy storage, are actually bigger challenges than just producing enough annual renewable energy.
- Main article: Achievements
Solar panels are directly connected to the following achievements:
- Produce more than 10 GJ energy per hour without the usage of steam engine.
- Steam all the way
- Win the game without using a solar panel.
- Changed tech requirement from Adv. Electronics to Electronics.
- Energy of the solar panel is now fractioned between all the networks it's connected to.
- Massive optimisations to solar panel logic.
- Significantly slowed crafting speed to 10 secs from 0.5 sec.
- Made solar panels pre-science pack 3.
- Unplugged icon shown when not connected to any power transfer device.
- New solar panel graphics.
- Priority of power consumption changed to consume from solar panel first.