Peak Shaving

18 thoughts on “Peak Shaving”

  1. I often wonder why dark materials are used for roofs, particularly in the sun-belt. My townhouse complex has a white roof with extra insulation underneath. And it gets cleaned twice a year.

    I remember looking at a rental about 1985 in Colorado that had an energy management system that would shut off certain appliances (like the water heater) if demand got too high. Then I thought it was sort of weird, but some utilities are implementing similar systems now for a rate reduction.

    Our utility solved the energy conservation problem with a fixed infrastructure fee, separate from the varying electricity fee. So all support the network, however much or little power is used. But they allow net metering.

  2. Thank you for wrestling this complicated issue. Impossible to do with a single post, of course, and impossible to complete in a single reply.

    I agree a lot. I think my main point of contention would be that things are getting better, if only in a 5 steps forward, 4 steps back fashion.

    I am also interested in “distributed” solutions more than what the New Deal era utilities are doing in their reluctant ways.

    I was a BIG supporter of the Obama era “Cash for Caulkers” tax credit, and I took advantage of it.

    One big hack we could employ is recognized by the feds — roof colors. Some save a LOT of energy.

    Yesterday, I bought a bunch of polycarbonate panels that are white-transluscent — I am building some, essentially, covered porches that can be enclosed in winter, but in summer will keep a lot of excess solar gain from hitting the stone walls of the house.

    If I had an infinite amount of time, I would install a perimeter of awnings such that summer sun (I live in a mild climate with often hot, sticky summers) would be diffused and lessened, while the lower on the horizon winter sun will be able to hit the windows and walls directly.


    1. I was down in southern California recently and saw new roofs being installed – mostly black and dark brown asphalt shingles. I asked the construction guys if it made the houses hot. They shrugged. Then I asked a couple of home owners I met on the street. Shrug. People are unaware of the energy implications of these choices. Personally, I installed a standing seem metal roof in light gray that bounces heat off in the summer (and also collects clean rain water.) It made a huge difference in indoor temperatures. That plus all the insulation I added means the house stays cool all summer with no air conditioning.

      1. Crazy, isn’t it? Yes, most roofs here in Virginia are dark, including my present residence, and that is crazy. Even NYS would likely benefit from light colored roofs. The roof was too new to tear off, and my first thought was that I would like to put slate on if I still owned it in 20 years, since that was what it originally had and the slope is steep (house has 1920s tudor pretensions.

        But now I think I would put a light colored standing seam roof on.

        What I quickly DID do was put the interior “e-shield” type stuff on — which works, but not as well as a light colored roof.

        I considered rooftop solar, but the solar people confirmed what I already thought — that the deciduous trees cast too much shade in the summer, and the evergreens too much in the winter for it to work, and, besides, for at least half the day they shade the black roof and it would be hard to make up that much energy savings if the trees weren’t there.

        Trees: Another sometimes solution.

      2. One big problem is that a lot of very simple technologies with big energy efficiency impacts get marketed as premium products in the US because it is presumed that the only market for such things are affluent individuals. I’ve found at least 3 examples of this, where simple energy-saving technologies are a lot more expensive in the US than overseas:

        1. When re-roofing a house, I was offered a more expensive “energy efficient” roof tile, it was just a lighter color.
        2. Ductless mini split heat pumps are far more expensive in the US.
        3. Solar thermal water heating systems are outrageously expensive in the US, so much that some have suggested that it makes more economic sense to install PV Solar panels and use a resistive heating element in an existing gas water heater.

        All three of these are technologies that are decades (millennia for the light roofs) old.

  3. So it’s only peripherally related…but here goes.

    Large-scale solar arrays (at least here in the Midwest) tend to be ground-mounted, which then imposes a need for spraying and weed control since they’re too low to get mowing equipment under and around.

    A couple I’ve seen are on taller structures over parking lots, which has a dual benefit of shading cars and dark pavement from contributing to the urban heat island effect.

    Wouldn’t it be wiser, long term, to require that new solar arrays “roof” acres and acres of suburban parking lots, near the grid and users, instead of remote deserts or fields? I guess there’s some “hardening” expense to protect against idiot drivers, but still…

  4. Peak solar insolation nearly overlaps peak air conditioning demand in the warmer states, so rooftop photo-voltaic panels could probably assist peak AC power generation. Such power would be generated right at the point of consumption, too – saving losses via long-distance transmission.

    1. It already works that way in California. Actually, it’s working *too* well, because peak non-solar demand has been shifted into the early evening, and there’s often excess on hot afternoon.

  5. The shift to utility solar is a result of the panel costs falling faster than other costs, which makes rooftop solar relatively expensive.

    Renewables subvert other energy sources because they are free at the margin and have wild, uncontrollable swings in output. Traditional power plants are designed for stable output, so this kills them.

    Energy efficiency is chugging along quickly, whether our culture wants it or not. America may not define the world’s Zeitgeist any more, but the train keeps rolling on.

      1. People don’t actually want energy, the want energy services. They don’t know what energy is.
        The energy business is huge because people profit from it. Renewables are profit killers. As soon as the profit disappears, the urge to generate more energy will disappear. It’s sort of like the business of selling music media like tapes, CDs and LPs. It seemed like an unstoppable juggernaut until the internet came along. Now it’s a curiosity.

        1. Er, to finish my comment, nobody ever really wanted the records. They wanted the music. In the same way, nobody wants energy. They want transportation, cooling, light etc.

  6. I think you have a great grasp of these issues. I might send this to some people I know as a primer on how the grid works these days.

    One thing that I reflect on often is how poorly designed government energy conservation programs are. For instance, there was a tax credit where the government would give the taxpayer 30% of the installation cost of a ground source heat pump. For a $30,000 install that works out to around $10,000. The obvious problem, though, is that you can only give that money to people that have a $10,000 tax liability, which means household income needs to be around ten times that (more, if they have children, contribute to their 401(k), etc.

    Many of these subsidized GSHPs made their way into 6,000 SF or larger McMansions.

    A family living in a 500 SF ADU which is space conditioned with a ductless unit will use about the same amount of energy per SF, but their actual energy consumption will be 1/6th or less. They, of course, receive no tax benefit from their decision to live frugally.

    Which is why I voted for a revenue neutral carbon tax here in Washington. It doesn’t take into account the relative efficiency, only the actual carbon production, which is a useful proxy for actual energy consumption. As a side benefit, it would benefit urban neighborhoods and preserve rural areas for resource production or large estates.

  7. Great discussion and insights.

    Utilities behave the way they do because they they are trapped in a New Deal-era regulated rate structure. Residential rate structures typically involve low or non-existent fees for grid connection, with most costs rolled into consumption charges. This is politically attractive, as it feels right for everyone to “pay what the meter says.” Experts even argue, straight-faced, that “poor” users with their small houses and lack of gadgets will use less than the “rich” with their large homes and abundance of shiny toys. Utilities therefore increase their (regulated) profits ONLY through consumption increases, as rate increases are frowned upon both by the public and by state public utility commissions.

    The reality is different. Efficiency improvements in lighting and HVAC mean that overall consumption is flat in most places, declining in others. The rich often can buy the most efficient products or even grid tied solar, reducing their effective consumption, while the poor are saddled with incandescent lighting, electric space heating, and ancient refrigerators. All while the aging, centralized grid is requiring more and more maintenance and upkeep. There is only so much a utility can do to hide it.

    My personal (Pittsburgh area, Duquesne Light) example: I pay ~$3/month for the immense privilege of grid tied, residential service, and ~$0.14/kWh for electricity use. Some of my neighbors have grid tied solar, and I think our utility pays retail rate for that power. This can’t last forever.

    As for “the cloud:” Today Western Digital/HGST announced a monster 14 terabyte, helium-filled, shingled magnetic recording hard drive, for exclusive sale to data center operators. The Internet of Things must be fed.

  8. The entire economy is structured the same way…outsourcing the means of physical production along with the resource consumption and pollution that come along with it. We can simultaneously congratulate ourselves for an economy that is more efficient than ever, consume more cheap stuff than ever, and talk about the outrageous CO2 emissions of developing countries. We all live in the shell game.

  9. A mishmash of comments here:

    The peak shaving system is elaborate and uses a lot of energy for the workers and server farms but – still comes out a lot better than the prior system. It’s not a shell game. It is more fragile, per the usual fragile vs. efficient tradeoff.

    The “problem” with rooftop solar is that it’s working too well. It got the grants, and got to sell back electricity at retail prices (wholesale would be fairer). Now there’s so much it has become a big financial hit. The changes will slow it down, but only by a few years, because of the rapid improvement curve.

    We have rooftop solar that covers most but not all of our needs. We could live on just the rooftop power, except that we didn’t install a system to disconnect from the grid, as required by California. Sometime in the next few years we’ll probably buy a battery and put in that system.

    It doesn’t make sense to replace functional existing cars with electric cars but soon if you replace them anyway it will make sense to buy electric. Not only do you save on gas, you save on maintenance because the drive train is much simpler. We have almost certainly bought our last traditional ICE car. Our next car will probably be a hybrid, and after that we’ll be buy all-electric ones.

    Even if you drive, if you have less of a distance to drive the energy cost goes way down. So walkable and semi-walkable neighborhoods are good even when you do have to drive.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.