Questions about 100% renewable grid

Can Wind Power Be Stored?: Scientific American.

Among the leaders is a Massachusetts company that plans to use hundreds of “flywheels” to store 20 megawatts of electricity, enough to power 200 homes for a day. Beacon Power Corp. is working with a $43 million federal loan guarantee for its $69 million storage project in Stephentown, N.Y., which is scheduled to break ground by year’s end.

Now, while I’m not very technical and mainly blog to store various links and generate discussion with my more technical online friends, it strikes me that the pro-nuclear advocates would point out that $69 million to store only 20 megawatts for one day means $3.45 billion to store a gigawatt for one day. Which, if baseload power is the thing we are after anyway, could probably build maybe 1.5 – 2 nuclear power stations if they are getting as cheap as the pro-nuclear guys are saying. However, I’m wondering if that isn’t a straw-man because while the wind mainly blows at night, there would also be a mix of solar and geothermal and CETO-ocean power during the day. In other words, we are not talking about building a 100% wind grid. Many of these power sources complement each other quite nicely and dovetail their supply around when the other source is about to tail off. So at a guesstimate, with NO back of the envelope calculations and just to illustrate the point, the equation is probably not:

100%  wind power + 100% expensive storage = very expensive electricity, but

40% wind power +  20-30% storage + mix of other renewables = mildly more expensive grid than we have now.

Sorry about that, I’m not a technician and I’ve stated clearly that these rough numbers were just for illustrative purposes anyway, to get the concepts out there.

Now here’s the real kicker that makes me consider nuclear in another light, and is part of a discussion I’ve had down at Dr Barry Brook’s blog Brave New Climate which supports Gen3 and Gen4 nuclear power plants.

IF it takes the same amount of money to build a wind farm of a certain hypothetical output as it takes to build ONE nuclear power plant of the same output, and then we have to add a solar power plant to cover daytime power as well, AND still add some storage for smoothing, why wouldn’t we just build the nuclear power plant instead?

I don’t know the answer. You’ll have to read the Brave New Climate nuclear V wind post for more. (Forgive any of my  late night ranting I may have contributed in the comments section. When I’m cranky my writing can become a little ‘left of field’).

I’m guessing that if wind is to have a chance to compete economically, there’s something about the wider grid that I’m not getting. Remember that coal power is ‘baseload’ and yet even it requires backup for the 10% of the time a coal plant is not running. So that means we build roughly 10% more coal plants than the power capacity rating we need (to put it crudely). But wind is only 30% of its nameplate output. So with these things in mind, lets return to my illustrative figures above because there are some assumptions I’d like to look at again. Think of the 100% power as supplying 100% of a town’s power.

100%  wind power for the town + 100% solar thermal + some storage = very expensive electricity when compared to one nuclear power station.

I changed the formula because the town’s power can’t be 40% wind power at any point, because the town needs 100% of it’s power supply all the time. In other words, there’s no hiding behind the old argument “But the grid will be a mix of renewables” because “mix” assumes you are over-building the grid’s power supply. Instead of  “dove-tailing nicely together” aren’t we actually talking about building 100% capacity supply from wind AND 100% supply from solar thermal during the day (even if it has some thermal storage,  I hear it is still quite expensive to provide storage ALL night) AND also building very expensive power storage backup systems like the flywheels listed at SCIAM above? Why not just build the one Gen3 or Gen4 nuclear power plant, with walk-away safety, baseload supply, eats a ton of old nuclear waste that would otherwise have to be stored for 100 thousand years and turns it into 100kg of waste that only has to be stored 1000 years, and even does the same thing to old nuclear warheads?

In other words, I want to ask the real energy experts like Herman Scheer one question:

“Does a mix of renewables mean doubling or tripling our power stations, and therefore doubling or tripling the costs?”

I’m simply not technically informed enough to come to any conclusions on this. It’s beyond me, so I am just putting out there that these are the questions I’m asking. The only villages I know of that are 100% renewable, at this stage, are various hippie permaculture places (that I love) but are not really mainstream city power supply situations. So they are off-the-grid Earth-ship homes, but do not supply gigawatts of power to a chemical factory. Or they are rural villages in Germany running off biomass plants which are not scalable to running our modern super-cities.

I will add one other point.

We may not be paying for all our storage capacity as part of extra utilities bill.

Better Place electric cars are going to be V2G. (Vehicle to Grid). When they plug in they will also be connected to the internet and talking to each other every 3 seconds. This enables them to charge during peak supply and sell back during off-peak supply, to help the owner offset some of his electricity bill.  Because the Better Place business model allows them to own the battery, they supply drive through automated battery swap stations. This means the cost of replacing new batteries does not fall on the vehicle owner, which spares them forking out $4000 every 4 or 5 years.

In other words, with the V2G technology and battery-ownership of Better Place, they are effectively providing free grid backup. We’ll only pay for it in the charge / km price, which is already cheaper than oil today, at an estimated Better Place business model of about 80cents / litre km equivalent energy! If you could find some vehicle that allowed you to buy km’s at an equivalent price of 80 cents / litre worth of energy, you’d do it right? Fuel is about $1.25 to $1.30 nowadays in Australia. Very soon it could be $2 a litre.

What are your thoughts?

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6 Responses to Questions about 100% renewable grid

  1. Pingback: Can we build a baseload renewable grid, or do we have to go nuclear? - Page 2 - Science Forums

  2. Barry Brook says:

    “to store 20 megawatts of electricity”

    You cannot store 20 MW of electricity, since MW is a unit of power. Do they mean 20 MWh?

  3. eclipsenow says:

    Sadly, most of the population (including myself) are not that technically literate Barry and just think in terms of big numbers, not actual technically correct units of power supply. They said enough to supply 200 homes for a day.

    It happens. I’ve even seen it happen on your blog. 😉

    As you can see, I’m honestly trying to struggle through these issues but do so from a non-technical background and struggle with the basic terminology, and am trying to present your arguments as a set of *ratios* that readers might understand in plain English.

    I wonder how Matthew Wright would reply to the above post? Mark Diesendorf?

  4. john morgan says:

    Good on you for working this through for yourself and keeping an open mind! If only everyone were prepared to make this sort of effort,


    • eclipsenow says:

      Thanks mate but this is not really a change in my position, which is that I welcome all alternatives to peak oil and climate change induced nightmares. Indeed, if possible I still prefer a renewable grid. However, I’m just trying to put some of the arguments you guys have been explaining on BNC into English. 😉

      There’s probably something I’m forgetting, like the concept of niche energy markets. EG: Diesel meets one type of energy market, petroleum another, jet fuel another and coal another. It may be so with the grids of the future, and I’m just interested in what the renewables experts like Scheer would say to the plain English question:

      “Does a mix of renewables mean doubling or tripling our power stations, and therefore doubling or tripling the costs?”

      As a humanities/Arts kind of guy, all I can say is that the final outcome will be very interesting because so many technical experts in one area are recommending their solution to these challenges, while other specialists get on with developing other alternatives all together. There are so many new approaches to our energy supply matrix that it makes my head spin. However, they mainly produce electricity, and don’t produce liquid fuels in any scale that matters.

      So we’d better get our electric transport, mining, and (alternatively fuelled) agricultural systems up and running before peak oil smacks us around too much hey?

  5. john morgan says:

    I don’t mean to infer a change in your position, just to honestly acknowledge an uncommon effort in engaging the ideas.

    “if possible I still prefer a renewable grid”

    Well, if wishes were fishes we’d all cast nets in the sea. However, things are as they are.

    I’ve also been hoping Diesendorf and others might engage the discussion at BNC – I’d be very interested in their take on the discussions there. But I agree, rapid electrification of fossil fuel systems along with decarbonization of the grid seems to be the imperative at this point.

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