So I know if you’re reading this, you’re probably pissed with me for not posting about the iPhone re: the latest updates, but the comments on the old post seem to be doing the job, so for now, I’m going to shift topics a bit (I promise, I’ll write a new iPhone post soon. I want to do some dev myself anyway).
I’ve said before on this blog that I’m an electrical engineering student right now. Specifically I really enjoy designing power systems: things that require lots of volts but even more amps. I’ve also sort of been an environment enthusiast for a long time and being a techie in general, things like veggie oil buses and renewable energy systems come as natural interests to me. The nexus of all these things is very convenient for someone in my situation: I like electronics, and all of these things require electrical design.
More specifically, though, let’s talk about renewable energy. The principal problem right now with things like wind power and solar energy is that they’re unpredictable. Hydro power doesn’t so much have this problem because most hydro dams have a man-made reservoir behind them and locks can be opened and closed as needed, but most other renewable resources with enough capacity for mass production are, in terms of availability, at the mercy of the weather.
The reason this is a problem is that our current grid is dumb. It delivers power from one spot to another, more or less instantly, with no wiggle room. In other words, the input (power generated) has to be slightly greater than the mass usage on the grid at any given time. If it’s less, obviously there isn’t enough power and you get brownouts or grid shutoffs. If it’s too much more, you’re just wasting energy, and if it’s not enough more, you run the risk of brown or blackouts caused by momentary spikes.
Sidebar for a moment: What is a brown out and what is a black out? First, imagine your cordless drill. When the battery is dying, the drill doesn’t stop all of a sudden, it gets slower and slower. If you let it go long enough, it eventually it stops, but mostly it just goes too slow to be useful, and loses all power against whatever you’re screwing or drilling. This is because of how a voltage source (like a battery or a power plant) works. A voltage source tries to keep the potential across its terminals constant. Think of it like a bath tub full of water, with a guy sitting there turning the faucet on and off as necessary to keep the water level constant (to go into depth, the faucet is like the chemical source of energy – the coal being burned, the nuclear fuel being fizzed, or in a battery, the chemical reaction going on). The motor of the drill, though, is eating this power ravenously, but it can only eat so fast. Usually, the chemical reaction in the battery can outstrip the motor’s demand, keeping the voltage level all the time. When that reaction starts to use up all its reactants, though, and it starts going more slowly, it can’t convert energy fast enough to keep up with the motor’s demand. As a result, the voltage across the battery drops, and puts less power into the motor, which slows down and loses torque.
The same thing happens on the electrical grid that serves your house. If the grid tries to pull energy out too fast, faster than power plants can supply it, the voltage on the whole grid drops accordingly, just like the tub draining faster than the guy working the faucet can fill it. Usually, when a situation like this is encountered, the grid fails before the power plants (that is, the grid’s wires would melt or burn or be otherwise damaged by so much transmission, and to keep everything safe, automatic shutoff switches kick in and some supply line is cut. Sometimes supply duty fails over to adjacent grids, keeping the lights on, but sometimes adjacent grids can’t supply enough so it doesn’t, or worse, it does fail over and the adjacent grid BECOMES overloaded and shuts off. In either case, the grid automatically shutting off results in zero voltage at your house, and it’s called a blackout (the lights turn off).
Sometimes, especially in California (they’re famous for brownouts), the grid doesn’t shut off. Instead, it stays on, and power plants simply can’t keep up. As a result of the tub draining faster than it fills, the mains voltage for affected areas drops outside of acceptable limits (in the US, mains voltage is 120v, but that is intended to safely vary within +-10% or so). This is called a brownout because the lights just dim instead of turning off (though other appliances may actually behave erratically or be damaged). There, now you know what a brownout is and why it might happen.
Since the output of both Wind and Solar plants depend intrinsically on the weather, this system isn’t very practical. That is, if supply=demand needs to stay true, and if demand varies with lots of factors, supply can’t also vary. We have to be able to control it. With wind and solar, we generally can’t. Basically, there are two options to achieve a grid powered entirely by abundant renewable resources. Either find a way to make those power sources variable (key aspect: increasable. We can always throw more coal on the fire, we need to be able to blow more wind on the turbine if we’re to replace the coal. We can always stop the turbine entirely, that’s not the problem), or instead, design some sort of grid where supply=demand doesn’t have to always hold true, only over the average across some period of time.
Seeing as how it’s generally impossible to conjure wind or move the clouds (not that either would be a good idea anyway), the only real option is to design a flexible power grid.
Enter the “Smart Grid”
The idea behind the smart grid is to build in storage and intelligent sensing such that the grid itself always knows how much power is needed and how much it has available to it in both original generation and storage. Designing components of such a system is one of my primary areas of interest as an electrical engineer. By converting to an electrical distribution system as intelligent as the internet, we stand to gain a LOT of leeway in the kinds of consumers and producers of energy available to us going forward. Just like a Prius reclaims lost energy by braking and saves energy by not using the motor when it doesn’t need all the energy it can provide, our new smart grid can sip energy over the long term from the ocean or earth below us (wave generation and geothermal heat exchange, respectively) for us to use when we really need it, maximizing our ability to generate energy and optimizing our usage of it, while acknowledging the fact that the general populous isn’t going to self-regulate demand on the whole.
And of course, it goes without saying that all of this is necessary if we are to do anything as a society about reversing or at least stopping our extremely unsustainable energy policies. It’s generally acknowledged that the atmosphere simply can’t support sinking any more carbon, which is the largest byproduct of our current energy generation techniques. Even assuming that we’re OK at this very moment, which we’re likely not, we’d have to basically shut off operations worldwide in order to reduce our carbon output to a level that the earth is naturally capable of dealing with. But that’s only the bad news. The good news is that if we pursue the strategy above, and if we do so quickly and successfully, we have much less to fear both immediately and going forward. The beauty of sustainability is that it’s sustainable, and that peace of mind doesn’t disappear after you’ve established sustainability the first time.
This post was written for Blog Action Day 2009, http://www.blogactionday.org/. The issue this year, climate change, happens to be both important and eminently relevant to me, so I chose to break my traditional content mold. Also, I’ll probably try to follow this up a bit later as there are some topics I feel I glanced over or didn’t cover deep enough.