Nuclear Power: Part 1 — The Grid
In today’s world of eco-consciousness and concern about global warming, I see plenty of people talking about alternatives to fossil fuels like solar and wind, but I’m concerned to see that almost nobody regularly talks about nuclear power. Even more perplexing is to see politicians who typically take environmentalist positions, actively campaigning against nuclear energy.
The goal of this series of articles is to give you my best, data-driven argument for why those who consider themselves environmentalists should be embracing nuclear energy as an alternative to fossil-fuels, and a necessary stop-gap on the road to a renewable based energy grid.
But What About Renewables?
The first thing to tackle here is the question of renewables, and it’s a legitimate one. After all, if we managed to capture even 10% of the solar energy that hits the U.S. in a year, we could power roughly 70% of the entire world. Why should we bother spending (a lot!) of money to build nuclear plants, and deal with nuclear waste, when we can just use renewables like wind and solar instead? The answer is more complicated than it seems, and requires a basic understanding of how our need for electricity changes throughout the day, and how our grid responds.
It’s important conceptualize our demand for electricity not as a flat line, but as a constantly changing curve, dictated by things like weather, season, and time of day. Here’s an example of how energy demands fluctuate over 24 hours:
You can see that there are substantial changes throughout the day, but that there is also a substantial base power demand of ~10 gigawatts that needs to be constantly supplied. This demand is called the base load, and is supplied by continuously running power plants that produce a relatively stable amount of energy at low cost, but which have a hard time rapidly changing output. These include coal, hydroelectric, geothermal, combined cycle gas, and most types of nuclear. The rest of the power is provided by two types of power plants that are called “load following” and “peaking” power plants, that can rapidly adjust to changes in energy demand, but do so at a much higher cost.
Renewables’ inability to consistently produce enough base load power is ultimately their biggest weakness. Conceptually, the problem is easily solved by increasing renewable production, and storing the excess energy in batteries for later use, but battery technology is still far away from being technically and economically feasible. For example, earlier this year Tesla installed 396 refrigerator-sized stacked of batteries in California. The batteries are reportedly capable of powering 15,000 homes for 4 hours, which sounds great until you realize that California has about 6.9 million 1-unit houses alone. If you do the math it looks even worse — given that the average household uses about ~1.2kW per hour, I estimate that these 396 batteries are only capable of delivering about 72000 kW over 4 hours. Considering that California’s average energy demands are around 24,000 megawatts (that’s 24 million kilowatts) at any given moment, you would need to discharge 132,000 of these battery modules every second to meet demand. Assuming a 5 meter footprint for these cells, with no space inbetween, the number of batteries you would need to supply power to California for a single day would take up 57 million km². The entirety of the US is only 9.834 million km².
Until battery technology matures, we are thus forced to rely on the aforementioned base load power plants. Unfortunately for the environmentally minded, this means that coal power plants make up ~26% of our total energy production. The only practical alternative is nuclear power.