In the book "Our Renewable Future" by Richard Heinburg and David Fridley the authors lay out a sober assessment of what it will take to convert the United States' economy to 100% Renewable Energy. There are a multitude of problems to solve (manufacturing, transportation) but I am going to concentrate on what it would take to convert our electrical grid to 100% Renewable Energy, since production of electricity is the number one source of carbon emissions in the US.
"Our Renewable Future" along with many other similar assessments point to 5 key massive undertakings to achieve this goal:
- More Wind and Solar Power (and other Renewables)
- More Electrical Transmission Lines
- Energy Efficiency
- "Demand Response"
- More Energy Storage (such as Home Batteries)
Let's tackle these one by one. First obviously we need a whole lot more Solar and Wind Power. Renewable sources of electricity make up just a small percentage of electrical generation in the US, and nearly all of it is from large Hydroelectric Dams out west. But we've built dams pretty much everywhere it makes sense to, so that leaves Wind and Solar as the major players.
Secondly it doesn't do much good to have a bunch of Solar and Wind electricity if you can't get it to where it needs to go. The western grid of the United States has been called "the greatest machine ever built by man" but unfortunately it was not built with large installations of Solar or Wind in mind. One commonly cited example is the need for massive high voltage transmission lines that connect the desert southwest (where there is plenty of sun) with the east coast. That way when electrical demand is peaking on the east coast in summer (say 3-4pm) we could use solar electricity from the southwest right when it is peaking (around noon). That said, these kind of cross continent lines will cost billions of dollars, and even more importantly involve getting approval from numerous states, government agencies, and require the cooperation of dozens of different utilities.
Third comes Energy Efficiency. This is a no brainer. Replacing incandescent light bulbs with CFL's or LED's. Buying a new fridge or washer that is an energy efficient model (greatly helped by those big yellow "Energy Star" stickers). All of this is tremendously helpful. And can save you money!
Fourth I list "Demand Response," a term you are probably not familiar with but is actually pretty simple. Basically it goes like this: a utility sets up a remote control system where the utility can turn off and then back on something in your house - usually your air conditioner. When electrical demand is really high they can turn off your air conditioner for a short time and then turn it back on. When the utility can coordinate this among hundreds or thousands of homes it can really help them deal with peaks in demand that would otherwise necessitate turning on another power plant. A related idea is the "internet of things" which would allow appliances like a clothes washer to know when electrical demand is low or high and run (or not run) accordingly. In a way you can almost think of demand response as a kind of battery... which of course is next on the list.
Finally there is Energy Storage, which includes Home Batteries. You can think of energy storage as the key that unlocks the potential of renewable energy. The sun only shines midday. The winds change. You can have all the Solar and Wind in the world but it really doesn't do any good in the real world unless you can store it for when you need it - we've already seen how Solar of only 10% can wreak havoc on a grid without energy storage. The most cost effective form of energy storage currently is called "pumped storage" which means pumping water uphill when you have excess electricity and then letting it come back downhill to make electricity during times of high demand. These are large installations requiring lots of space, a mountain (or at least a big hill), and additional transmission lines. Let's consider this question - where is the best place to put energy storage? For Solar and Wind obviously the answer is where it is sunniest and windiest. But energy storage? The answer turns out to be that energy storage is best spread out everywhere as evenly as possible. Why is that? Two reasons: the first is that if each battery is small, then there isn't too much electricity coming from each individual battery, which means the current grid could handle it - i.e. no new additional transmission lines would be needed. This is a huge deal when the country will already be struggling to add all kinds of new transmission lines anyway. The second is that some electricity is lost over transmission lines, so if the battery is near to the homes and businesses it is serving then the losses are less. And nothing is closer than the inside of your own home is there? So what kind of energy storage comes in small packages that is spread out evenly all over the place? The Home Battery of course! Even better is if grid operators have ability to control a fleet of home batteries remotely - similar to with demand response they would be able to store electricity when it is plentiful and then use it when demand is high. I dream of a day when "Home Battery Co-ops" across the country work together with their utilities.
There are innumerable things that need to happen if we are going to make a serious dent in climate change, but a Home Battery is certainly one of the most potent. All of the above is necessary. Adding transmission lines and demand response are things that our beyond our personal control. Being energy efficiency conscious is a no brainer. But when it comes down to the last mile, Home Batteries are absolutely necessary too.