Better Uses for MIT Solar Storage Breakthrough


Energy Ideas

A news story has been making the rounds for the last week or so, heralding a revolutionary breakthrough for solar power.  The short version, they’ve come up with an amazing new way to separate water into hydrogen and oxygen, using an innovative new catalyst that works at room temperature, low pressures and yields efficient conversion.  Great so far.  They’re touting it as a breakthrough for home solar installations.  This is a brilliant technology, and if it’s as cheap as they claim it will play a huge role in solar.  But not the way they’re saying.  This does not belong in the home.

Here are some articles.

Screen caps from Daniel Nocera’s MIT video.

I really had to spend some time reading on this before I started this post. When I first saw this article starting to pop up in blogs and Google Alerts, I didn’t think much of it. “10 years away” too often means “never”, so basically I lost interest. But the article kept popping up and it seems that they’ve got something useful that really works, and it will probably lead to commercial applications.  So in this case, “10 years away” might actually mean 10 years away.  Cool!

Check out Daniel Nocera’s MIT video for a decent overview of the technology.

I want to be totally clear, I think this is an absolutely amazing technology, and hell, I’ll go one further and say that when it comes out, I’ll invest.  But it’s a bad fit for residential solar and an amazing fit for utility scale solar.  After some thought, I want to address a few points made in discussing this technology.

Point 1: No solar energy at night is what’s holding solar back.

In the video Daniel Nocera says the following:

“It really opens the door for the large scale deployment of solar, because we have an easy way … to store that energy.”

This is just wrong. On the most basic level, we don’t need more electricity at night. We need more in the afternoons during peak demand. If you look at the daily electrical consumption (examples below) you’ll see that the night time price of electricity is a  fraction of what it is during the day.

Typical Daily Demand Curve

Typical Daily Demand Curve

LMP is Location Marginal Pricing, a standardized method of describing electricity pricing.  PJM Interconnect is a regional transmission organization in the North East.  Source: NRELUnderstanding the Economic Value of Electricity Storage: Some Key Drivers.

Hourly Price of Electricity

Hourly Price of Electricity

Source: Demand Side Management

Solar energy, especially solar energy with tracking capability, or concentrated solar thermal systems with built in thermal storage, produce energy when we need it the most – during peak demand.  Utility scale electrical storage would let solar facilities store the cheap morning electricity generated prior to peak demand, and output more electricity during peak demand.  (Solar thermal already does this by storing heat, but it can only be stored for 6 hours.)

Solar Tracking and Co-Firing Demand Durve

Solar Tracking and Co-Firing Demand Durve

Source: Hal LaFlash, PG&E – Utility-Scale Solar Power Generation Presentation.

Night time electricity is incredibly cheap, and if there is lots of nuclear, geothermal, hydro or wind power in your area, it can get close to free. Wind power is most productive in the evening and at night, so if you really need more power at night, throw up a turbine and you eliminate the need to install (in every home mind you) hydrogen and oxygen storage tanks, fuel cells, water tanks, piping, inverters and whatever else you need to run this system.

Basically, if the big advantage of this is that it provides power at night, it’s solving a non-existent problem.  Solar benefits from storage, but not the way they seem to imply.

But the real thing that’s holding back solar energy is that the cost compared to the power output is still higher than just buying power off the grid.  (Something we at Morgan Solar are working to change soon enough.)  Even if this system was 100% efficient (which is impossible) it would still mean more equipment and more costs for the same amount of power. That they’re suggesting you shift power from when it’s most useful to when it’s least useful, which doesn’t really make sense.

Point 2: This is a solar technology.

After looking at this, reading their website, watching their video etc, it’s fairly clear that this system electricity, and the source doesn’t really matter. This catalyst uses electricity to run the system, not photons, heat or anything else particular to sunlight.  Any electrical source would work.

As cool as this is, it’s not really “solar storage”, it’s electrical storage.  In a home installation, this system would provide MUCH better returns if you used the super-cheap and abundant night time electricity from the grid to store hydrogen that you could burn during the day.

Point 3: This would be cheap and useful for providing nighttime power

There is just no way that this system could be cheaper than a few more wind turbines. There is no nighttime energy crisis. Electricity peak demand is from around 4PM to around 7PM. High demand is from noon to 8:30PM or so. No matter how cheap this system is, there is no way you could reasonably justify the costs of hydrogen and oxygen storage tanks and a hydrogen fuel cell to provide power at night.

Point 4: Getting off the grid is a good thing

I hear many people talking about “getting off grid”. It really sounds better than it is.

The electrical grid is one of the most astonishing achievements of modern society. It’s totally democratic, even the poorest of the poor can be and usually are connected, and it improves absolutely everyone’s life.  Access to indoor light, heat and appliance power helps everyone.  We’ve spent the better part of a century building it for a reason, and it’s so effectively built and managed that we forget about it most of the time.  You plug something it, it turns on.  We only pay attention to it during windstorms or the occasional (very seldom) power outage.

But wanting to disconnect sounds like a good idea.

“If I generate all my own power, then I’m not contributing to whatever bad stuff happens when the utility generates electricity. Carbon, pollution, all of that, I’m not involved if I disconnect…”

Technically true, but what about your surplus power? What happens when your power system breaks down? (Which it will occasionally.) What about the people who can’t afford the up front costs of going off grid?  Sure you can go carbon free if you disconnect, but you can go carbon negative if you stay connected and give back.

Basically, it makes much more sense for us all to contribute to the grid.  So using this to “liberate” yourself from the grid is a non-starter.

Increase our local home production as much as we can, while decreasing our consumption, so we’re giving back more than we’re taking. In this model, a couple of things happen. First, it provides more of a financial incentive for upgrades to the grid that would benefit everyone, and second, it contributes to a more stable, productive and low cost power grid for everyone.  Staying connected and giving back makes more sense than disconnecting.

This hydrogen fuel cell doesn’t generate power, it stores it, and doesn’t do anything to lower household consumption. It’s great if you need a battery back up, or if connecting to the grid isn’t an option, but all it does is store power.

Practical Uses for Cheap Efficient Electrical Storage

Now, to be clear, I think cheap, efficient and reliable energy storage is an amazing thing, and something that we need. But not for storing solar power at home. Here are some smart scenarios for using this breakthrough:

  • Hook an industrial scale version of this thing up to a nuclear power plant, run it at it’s optimal power output 24/7, store power when the grid doesn’t need it and dump the power onto the grid when demand goes up.
  • Hook these up to wind turbines, which are intermittent and unpredictable, so you get a more steady baseline power output.
  • Hook one up at home, charge it up all night, and use it during the day to lower your power consumption during peak demand.

The real value of this in the solar market will be for what’s called Load Shifting.

  • Hook up an industrial scale version of these to a solar farm, so that that the power generated in the morning (which isn’t worth much) can be stored and dumped onto the grid in the afternoon and early evening when it’s at peak demand.  At home, this makes no sense, on a utility scale, it’s brilliant.

Another amazing application would be local demand management.  They spend millions of dollars topping up local power dips and trying to get the power from the big utility stations to the widespread grid.

  • Put neighbourhood versions of these in trouble spots, store hydrogen when there’s lots of power and then top up the grid when you start facing brownouts or rolling blackouts.

In all these cases, you’re taking power when it’s cheap and not in demand, storing it, and then using it when (or where) it’s actually needed.  But power at night? Don’t need it, don’t want it, it’s nearly free already, so why use daytime energy to make it?

This is huge, this is a major breakthrough, if this works and people can use this technology to make utility scale systems that stock-pile energy and deliver it when needed, they’re going to make billions.  But installing these in the home, tied into residential solar – pass.

For a rediculously detailed economic analysis of storage for renewable energy, check out this report from the NREL.


7 responses to “Better Uses for MIT Solar Storage Breakthrough

  1. The MIT tech is certainly a general energy store not just solar, but its a better news item hooking it to greener power than buffering excess nuke or fossil to increase efficiency.

    Regarding home wind turbines,here in the UK the value of small home turbines is now getting questioned:

    If you have the space, like many in the US / Canada do, then a decent sized turbine proably makes sense, but urban ones may not.

  2. Interesting, I’ll be speaking with someone later today that runs a conservation area and environmental research station, and they have a variety of wind turbines installed. His opinion might be interesting.

  3. Even the economist is uncritical. Connecting this development to solar is a pure headline grabber, and the irony is they’re pitching their invention as some miracle cure for Solar. (Use the successful industry to pitch our invention, but bill ourselves as the innovation that will “save” solar.)

  4. Alan, interesting paper. Hight and blade length matter for wind, and at some point the system doesn’t scale well. Going to spend some time digesting this.

  5. Load issues could easily be resolved if we had a true world-wide grid since regional peaks all occur at different times and so even out.

  6. I’ve never heard anyone suggest that before – got any links? Because off the top of my head, wouldn’t the transmission losses be astronomical? You lose 5 to 7% now, run an electric cable across the Atlantic and how much do you lose? Further, the costs would be extraordinary, and it would be hard to demonstrate that they would be less than ramping up local capacity or local capacity buffering. Also, managing a regional grid is hard enough, and you still sometimes face localized shortages even when there’s more than enough power overall, because managing balanced load can still be a challenge.

    Maybe I’m missing something, but a global grid sounds like a science fiction level challenge. “Easily resolved”? I think we’ll have colonies on the moon before we have a world-wide grid.