Before the War, citizens of North America took electricity for granted. The coast-to-coast network of fossil fuel plants, nuclear reactors, solar and wind farms, and dams kept the lights on at all times of day or night. Electricity was cheap and plentiful, with infrastructure improvements preventing the summertime brownouts that visited the previous generation. Then a rain of atomic warheads, their accompanying electromagnetic bursts, and anti-infrastructure chemical agents struck, followed by an abortive ground war. Survivors near the cities learned what the stars look like. No one in North America ever took electricity for granted again.
After the War, surviving communities had to make local resources do the work that cheap and abundant electricity did before. Many isolated communities were lucky enough to be near a renewable resource, such as a geothermal plant or a solar farm. Even those towns had to first repair the electrical circuitry destroyed by the waves of EMP from the War, and some lacked the materials and expertise to do so, so their renewable power sources have laid dormant. Other towns had access to fossil fuel plants and the raw materials to power them, or to nuclear reactors and stockpiles of fuel. These communities often absorb others, with smaller pockets of survivors flocking to the safety promised by lights shining in the night.
Power does more than create light to see and heat to cook by. It can move machines, enabling local industries. And it can move airships, turning the gears of exploration, commerce, and war.
Advances made in the years before the War greatly increased the efficiency of solar power collection and the ability to store that power in batteries. High-efficiency solar cells come in rubbery sheets of dark, semi-translucent gel, with wafers of photovoltaic gel suspended within. These sheets are portable, able to be rolled up like a mat for easy transport, and come in many varieties of length and width. They can be stretched out in fields, or on rooftops, or on trays intended to turn to help them catch the sun.
Solar mats are a popular power source for airships, but craft that rely on them must typically moor at night. It’s not uncommon to see airships, particularly from the Southwest or Mexico, with the upper halves of their envelopes quilted over the these black rectangles.
Some places cut off from renewable and liquid fuel sources went old-school. Vegetation is still plentiful over most of the continent, despite widespread devastation, and water still flows where it used to, though its potability may be in question. Many of the isolated communities to survive the War were also the type to preserve historical artifacts, including steam locomotives and other steam-powered devices. With ancient, reliable technology in hand, simple fire and water can be used to generate kinetic energy, which in turn can power a dynamo, or a sawmill, a workshop, or even the propellers of an airship.
Steam-powered airships are rare, but an impressive sight, with the stripped-down guts of an old locomotive bulging from the gondola, and its crooked smokestacks angling off to the sides around the envelope. Steam powered flight makes for slow going, and the weight of the engine prevents the airship from lifting much else. Steam does have an advantage over faster combustion and nuclear powered engines, though. Where combustion and nuclear power require refined fuels that can be expensive to trade for, a steam-powered craft can set down most anywhere to fell a few trees and chugga-chugga off again.
North America was lousy with internal combustion engines when the War happened. The EMP wrecked the electrical components, but nations of drivers meant plenty of mechanics able to rebuild the engines. However, the War destroyed the commercial network that delivered fuel across the continent, meaning that communities without direct access to an oil source ran through their available gas supplies quickly, or else have been carefully shepherding it for essential tasks and emergencies. Towns in Mexico-conquered California and among the Lone Stars in Texas have functioning wells and are refining and exporting petroleum fuels, and some towns elsewhere in the wasteland have access to Pits that convert biomass into an approximation of diesel or gasoline. Deseret, among others, is experimenting with combustion engines that run entirely on ethanol distilled from vegetable matter.
Airships powered by combustion engines boast range, speed, and reliable power. However, they must be careful not to range too far beyond the territories where they can obtain fuel, lest they become stranded.
Commercial nuclear power underwent advances just before the War similar to solar power with the advent of small-scale thorium reactors. The most common useful isotope of thorium is something like a hundred times more abundant than equivalent uranium, and is safer to handle in its raw form, though the concentrated waste from a modern thorium plant is dangerous enough that it’s usually dumped out somewhere far in the wilds of the wastelands. Refining thorium fuel is an intensive process, but many large-scale thorium reactors were placed in communities near rich sources of the metal with refining facilities onsite. Thorium fission plants are efficient, reliable, and mostly safe, but if something goes wrong or breaks down, the knowledge of how to rebuild or repair it is held by very few people.
Small-scale thorium plants are very occasionally used to power airships, usually those sponsored by large post-War governments such as Deseret or the industrial overlords of the Great Lakes. Nuclear power is seen paired with surviving examples of pre-War repulsor technology, its steady output of electrons keeping the plates humming and the fearsome warships they’re attached to aloft. To have a thorium reactor on their own airship is a dream of many an experienced trader and privateer, to be able to zip across the continent day and night on a minimum of fuel.