This is a draft. The readers here can be the editors and find my (probable) mistakes.The US, how do we get from where we are to 0% fossil fuel use?
Where are we now?
Let’s start with US primary energy consumption in 2016. All the energy we used. I’ll show a cut down version of the 2016 NREL Energy Flow chart. I’m leaving out the middle stuff (where the energy gets used) and showing only the inputs - Primary Energy (left) and the amount we use (Energy Services) and the amount we discard - Rejected (right)
Above the green/black line are renewable energy sources and nuclear - the low carbon, non-fossil fuel sources. We need to move Biomass up with them because while burning biomass does release carbon it is carbon that was already in the above-surface CO2 cycle. It’s not carbon we extract from under the surface.
The numbers in the boxes are in Quads of energy. A quad equals a bit over 293 TWh. From here down I’ll uses TWh as more people are familiar with watts than quads (10^15 BTU).
Here’s our non-fossil fuel generation totals for 2016. I’m listing them with and without nuclear which I will explain later.
Now the right side of the graphic. That shows us how much energy we actually used (Energy Services) and how much we lost in waste heat (Rejected).
Coal plants are about 35% to 40% efficient. That means that if we put 100 kWh of coal energy in the furnace we get about 35 kWh to 40 kWh of electricity from the plant.
ICEVs are about 20% efficient. Put 100 kWh of gasoline energy into the tank and only 20 kWh turns into kinetic energy moving us down the road.
Coal wastes about 60% to 65% of the primary energy we feed into a coal plant. ICEVs waste about 80% of the energy we put in their gas tanks. We have no need to replace that energy as it serves no purpose. It’s the very thick wrapper on our burrito which we toss in the garbage.
In 2016 we used 30.8 quads of energy. 9,027 TWh. We generated ~60% of that amount with non-FF sources, ~33% excluding nuclear. To be fossil fuel free the US would need to generate an additional 3,582 TWh (or 6,050 TWh without nuclear) from non-fossil fuel sources.
In 2016 the US generated ~53 TWh more electricity with non-fossil fuel sources than in 2015.
If we want to arrive at ~0% fossil fuel by 2050 then we need to install non-fossil fuel generation 1.8x as fast as we did to create that 53 TWh (3.1x w/o nuclear).
If we want to arrive at ~0% fossil fuel by 2040 then we need to install non-fossil fuel generation 2.5x as fast as we did to create that 53 TWh (4.2x w/o nuclear).
1.8x ? Very doable. 2.5? Shouldn't be hard.
Can the US double the rate of installing renewable generation? Sure, a piece of cake. Large portions of the US (the Southeast, in particular) are just now starting to install. We, just now, are hooking up our first offshore turbines and have yet to launch our first floating turbine. Prices for wind and solar continue to drop. And the realization that single-axis tracking not only greatly increases solar farm output but also lengthens the solar day should mean major increases in utility solar installation.
But we should be aiming for 4.2x. Doable
Why without nuclear?
First, our nuclear plants are old and many will probably die a natural death well before 2050. Over half of our reactors are losing money and will require subsidies to keep from going bankrupt. Some of our reactors are already scheduled to be closed by 2025.
And if there happens to be a major nuclear disaster in the US, probably anywhere in the western hemisphere, there would likely be immense pressure to close all US reactors rapidly like we saw happen in Japan. A low probability event, but one we can’t ignore.
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