We expect to see more and more renewable energy sources such as solar and wind in the coming years. These are highly unpredictable sources of energy. When the wind is blowing and the sun is shining, we have a surplus of energy that needs to be stored for days where the consumption exceeds the amount of energy being produced.
What do you think are the most promising technologies to store utility-scale energy at this time?
It is a function of what technology we are using to generate the energy in the first place. For instance, if we get heavy into solar thermal energy, we need to utilize entirely different storage methods. This energy is heat – not electricity as it is in for instance wind turbines or PV-cells.
We can store heat energy a lot less expensive than electrical energy. You simply heat up a substance to a couple thousand degrees and you use that heat energy, as you need it. Molten salt heated by solar energy is a good example of this.
So if we were heavy into concentrated solar power (CSP), that would be a direction we want to go in, as opposed to if the world was covered in PV-cells.
The vast majority of energy storage right now is pumped hydro. In other words, taking water from a certain elevation and pumping it up to a higher elevation, and extracting the energy from the water coming back down whenever you need it.
Pumped hydro is obviously not portable and you can only use it at certain topographies. If you don’t have a natural change of elevation it would be horrifically expensive.
Similarly, I’m not a huge believer in compressed air (CAES). There are two implementations of this technology on the planet today and I think there is a reason for that. The choice of caverns is very specific for the rate at which you need to charge and discharge. You pay a huge penalty in terms of thermodynamic efficiency if you have the wrong cavern for what you’re doing. The world does need more implementation and testing of this technology, but I’m not sure if it will be a good long-term solution.
What about batteries? People say that zinc-air might be suitable for storing energy on the grid. Is this true?
Batteries are ridiculously expensive at the moment, but that is not going to remain the case forever. Breakthroughs in zinc-air battery technology might get the prices down to competitive levels in the near future. You will be able to deploy batteries on grid-scale if you lower the price and this promises to do just that.
This technology has been through 5000-6000 cycles of charges and discharges in the laboratory, and has fantastic characteristics in everything that is related to grid scale. For instance, you don’t really care how big or heavy it is if it where to be implemented on the grid, as you certainly would for electrical transportation.
Electric transportation is another wild card in all of this. We have 230 million cars and trucks on the roads in the United States. If we replace a significant number of those to be driven by electricity, and tie them into the electrical grid system, the equation changes completely.
I am a believer in zinc-air. We have had air-batteries trotted out every couple of years since I was a little kid, so I’m skeptical as anybody should be, but I believe and trust the people developing this technology.
What do you think about hydrogen as an energy carrier? Do you see hydrogen as a part of our energy storage system in the future?
The beauty about hydrogen is that it is portable. However, the delivery infrastructure itself has not been developed. There are 3.5 billions square miles in the continental United States. In addition to this, electrolysis of hydrogen itself is fairly inefficient. By the time you split the water and pull it through a fuel cell, you actually consume 3-4 times more energy, as you would through some other means, for instance charging and discharging a battery. “People keep talking about hydrogen, but I have no idea why. I really don’t see it.”
The cost of batteries is going to come down to the point that you can put 50 kWh in an automobile at a reasonable price, which gives you a couple of hundred mile range. I don’t see why people want to drive more than 300 miles a day. I don’t think we are more than 10-12 years from that, so why should we invest trillions of dollars in an entirely new fuel delivery infrastructure? I don’t see it.
There are other types of liquid fuels we are trying to develop. Everybody is talking about algae biofuels. There are breakthroughs that can come further down the line, but biofuels has a limited use in my estimation.
Having said that, I am a believer in synthetic fuels. There is a company called Doty Wind Fuels that has made enormous breakthroughs in this subject. You can take off-peak wind or any source for that matter, and generate hydrocarbons that are high quality diesel or high-octane gasoline. That’s basically taking wind energy that otherwise would not be used and storing it for times when needed.
How far are these methods from being implemented on the electrical grid to store energy?
There is no good answer for when utility scale energy storage will be implemented for the following two reasons:
First you have the technology issue. Although many of these technologies looks promising on paper and some perform well under testing, we could be decades away from being able to implement them on the electrical grid.
Then there are the economical and political issues. If we want utility scale energy storage in the United States we have to create a political and economical infrastructure that provide incentive. Who is going to pay for this? It’s hard to imagine one group taking the responsibility for something everyone will benefit from. At least in the United States that’s a very tricky question.
We are in an election year in the United States. We protract and drama our choosing of a president like no other country on earth. You can imagine the rhetoric that goes on in a subject as large as energy.
I am still dumbstruck when I hear people say that they don’t believe in basic science. In other words, that all of the work associated with many thousands of people that try to understand what is going on with our environment is wrong, that global climate change is a hoax, that there is nothing in the matter with continuing to pump all this stuff into our atmosphere and the oceans. The whole thing is completely astonishing to me.
I have a simple mind and I am a product of what I read and the people I speak to. Not only am I anxious to hold the belief, but also incapable of holding one, that counters the belief of thousands of climate scientists. It would be thinking like the earth is flat.
When do we need utility energy storage?
We do need storage eventually. In the United States we have less than 2% renewables on the grid, so the concept that we need storage to take that to 10 percent is completely fallacious.
We face many challenges when it comes to implementing large-scale renewable energy. What are these and how important is energy storage compared to them?
We get almost 50% of our electricity from coal. This is clearly unsustainable. Unfortunately there’s a ton of coal in the ground, but it’s killing us. We are gradually starting to understand this.
Last year, 13 200 Americans died directly as a result of coal pollution and there are all kinds of diseases cropping up all over the place associated with this. We are trying to mitigate this with “clean coal” among other things. We have run up against the wall when it comes to this.
Maybe we are not running out of oil, but we are certainly running out of easily accessed and inexpensive oil.
Nuclear is not an option. It’s extremely expensive and by the time you could possibly design, permit, build and deploy a nuclear reactor in the United States, which is 8-10 years, the costs would be even more ridiculous. In addition to the danger and the public outcry, the costs are going to go through the roof, while the costs of renewable energy are falling every day.
Then there’s electric transportation. We aren’t going to drive Hummer’s in 50 years. We do have a big problem to solve. We just crossed the one billion automobiles mark on the planet – a lot of combustion engines to replace, which I do believe will happen.
At the same time we need to build out the charging infrastructure. Most of the gasoline stations in the United States are prewired for 480 V three phase power. The process of getting there in terms of charging infrastructure is significant, but not insurmountable.
We are talking about the Smart Grid, and all these neat uses of information to increase the efficiency of our energy use, but we are a long way from that. Our grid is outdated and Thomas Edison would recognize most of it if he were to look at it.
The costs of technologies such as solar, wind, biomass and geothermal are coming in line. “We are heading in the right direction. Energy storage is an important component, as all of these things are.”
The problem is that it is happening so slowly, especially in the United States. My question is how much damage are we going to do in the process? Are we really willing to sit around, while A) China leads the world and B) We simply do so much damage to our ecosystems that it’s irreparable.