Renewable Energy Mix Calculator

The calculator sums your seven generation-source inputs and scales each one by 100 divided by that total before doing anything else. So entering shares that add to 98% or 103% doesn't throw an error — it just rescales everything proportionally to fill 100%, meaning the relative balance between sources you entered is preserved even if the raw numbers you typed weren't perfectly normalized.

The emission factors used here are lifecycle figures from IPCC AR5 Working Group III's Annex III (Table A.III.2), meaning they include impacts from plant construction, fuel extraction, and other indirect sources, not just what comes out of the smokestack (or the lack of one) during operation. Nuclear, wind, and hydro all land in the 11-24 g CO2/kWh range because none of them burn fuel during generation, so their lifecycle footprint is dominated by construction and materials rather than ongoing combustion.

It doesn't distinguish between coal, gas, and oil individually — it computes one blended average intensity across all fossil generation weighted by each source's actual share, then calculates how much of that combined fossil percentage must shift to renewables (assumed to average 25 g CO2/kWh) to hit your target. In reality, gas is typically displaced first as the flexible marginal source before coal, but this static model doesn't capture that ordering.

The required renewable share output is capped at 100% before display, so an infeasible target (one where the math would otherwise call for more renewable generation than the grid has room for) simply shows 100% rather than a number above it. That's a signal your target reduction can't be met through generation-mix swapping alone — it would need demand reduction or other measures alongside the mix change.