The last 20% is the expensive 20%

Everyone argues shore power vs solar vs generator with feelings. Let's use structure.

Shore power is almost always the cheapest energy available — often a few cents per kWh, sometimes included in a site fee. Zero equipment cost, infinite capacity. Its only downside is requiring a plug.

Solar has high upfront cost and essentially zero marginal cost. Divide total system price by lifetime kilowatt-hours and the per-kWh number is genuinely low — but only if you use the capacity. A large array powering a laptop is expensive electricity.

Generator has moderate upfront cost and real fuel cost per kWh — typically the most expensive per unit, plus maintenance, noise, and CO risk. Its virtue is working on demand, at night, in winter.

The honest conclusion: these aren't competitors, they're a portfolio. Shore power when you have it. Solar as the free baseline. A generator or alternator as the backstop.