I was messing around with the code to make it so the electric boiler could be useful for early energy production, which I know it was not added for this but I just wanted to try and make it easier for myself. The issue I run into is when I change the energy consumption to anything lower; the steam output also lowers.

A boiler takes in energy of one type (electrical, burner) and creates that much energy's worth of steam. If you want to get more out, you need to increase the efficiency (effectivity) of the energy_source above 1, eg add the line effectivity = 2 within kettle.energy_source and you'll get 2 kW of steam energy out for every 1 kW of electricity you put in it.