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No More Tinkering: How Reinventing the Oven is Like Reinventing the Grid

smart grid future oven

How do you build a better oven? That’s a question Nathan Myhrvold, former CTO for Microsoft and foodie recently discussed.  He pointed out that today’s electric or natural gas-powered oven is designed on the principle first put forward five thousand years ago to dry clay bricks.  Kitchen technologists since then have been tinkering with that basic design – even though the objective of food preparation is often at adds with the objective of baking a clay brick, with the possible exception of holiday fruit cakes.

His exploration of how to build a better oven is a useful analogy about how we think about building a better electrical grid.   We can continue to tinker around the edges, making small, incremental improvements to existing technologies, or we can start over and work with entirely new technologies.  For example, we can continue to try to commercialize carbon sequestration technologies to make fossil fuels less polluting, or we can put our money in clean from the get-go renewables.

Myhrvold offers a fascinating description of the problems with existing ovens right from the moment you turn them on.  Today’s ovens are inefficient.  They consume too much energy for the output we get. The same is true of today’s electrical grid.  We lose 6 -10% of the energy along the supply routes from those remote, centralized sources of generation to the flicks of a million switches that make lamps glow.  The technologies to reduce those losses in the traditional electricity supply chain tinker with the problem.  A Smart Grid reconfiguration of the grid from centralized to distributed energy resources (DER) co-located at the point of consumption is a fresh approach that simply eliminates the line loss problem.

The problems with ovens aren’t simply about wasted energy.  The energy is often in the wrong areas.  The oven and the food contained within are not very responsive to each other’s status.  A cake may be baking too hot on one side of the oven and too cool on the other.  This misapplication of energy exacerbates another shortcoming – ovens provide insufficient and often inaccurate feedback about what’s going on inside them.   The only way cooks can really know what’s going on is to open the door and conduct a visual inspection.  As the IEEE Spectrum article explains, that simply compounds all the energy waste issues in the modern kitchen oven.

The problems of balance and lack (or inaccuracy) of feedback apply to today’s grid too.  Sure, grid operators do a good job of balancing the grid, but it requires a significant effort with an expensive outlay of capital and energy waste.  Here’s where another Smart Grid technology group comes into play.  Sensors deliver situational awareness of grid operations, and improve the abilities to deliver the right amounts of energy at the right places at the right time without wasting as much energy.  In fact, in many scenarios, reducing demand for electricity – also known as demand response (DR) – is a better answer than increasing generation capacity.  Sensors, and their companion actuator technologies are already successfully automating electricity reductions (or responses) on a facility-wide scale – such as dimming lights or bumping an air conditioner temperature up a degree.

And guess what?  Sensors address the situational awareness problem in ovens, and can include communications capabilities to alert us when food has completed its cooking cycle or needs skilled human intervention.  Just like the grid, sensors plus communications technologies in ovens makes them smart too.  Both ovens and the electrical grid benefit from innovative thinking that put less emphasis on technology evolution and more emphasis on technology revolution.  Consumers of both will be better off for it.

Photo Credit: Grid Future and Oven Design/shutterstock

Christine Hertzog's picture

Thank Christine for the Post!

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Bob Meinetz's picture
Bob Meinetz on Jul 9, 2014 12:39 am GMT

Christine, you write

In fact, in many scenarios, reducing demand for electricity – also known as demand response (DR) – is a better answer than increasing generation capacity.  Sensors, and their companion actuator technologies are already successfully automating electricity reductions (or responses) on a facility-wide scale – such as dimming lights or bumping an air conditioner temperature up a degree.

The message seems to be that consumers should accept the idea renewables aren’t robust enough to meet demand for energy, and it will be their responsibility to meet somewhere in the middle. Do you really think consumers will allow the variability of sources like solar and wind to dictate the terms of their energy consumption?

Leo Klisch's picture
Leo Klisch on Jul 9, 2014 2:53 am GMT

If they can save enough money to make it worth changing habits a little – yes. Off peak rates are a well accepted means for utilities to use excess generation when demand is low and charge higher rates when demand is high. As Christine says, we just need to shift into high gear with a more a more robust grid with more automation on both the supply and demand side. No matter the generation source it makes sense to level the demand side as much as possible.

Bob Meinetz's picture
Bob Meinetz on Jul 9, 2014 3:49 am GMT

wind, considering the demand side is increasingly being leveled by diesel generation DR makes no sense at all:

Backup generators now provide an estimated 10 to 20 percent of the roughly 10,000 MW of demand response that is in service on the PJM Interconnection, a section of the U.S. power grid spanning 13 states from Illinois to the Atlantic Ocean.

Already the largest consumer of demand-response services nationwide, PJM has lined up about 5,000 more megawatts for the summer of 2015. But it does not know exactly how much of that would come from diesel generators, said Paul Sotkiewicz, chief economist at the grid authority.

This means that on sweltering summer days, when people rush for the comfort of air conditioning to avoid heat and smog, enough electricity to power millions of homes could end up coming from diesel generators that are not subject to federal air pollution standards.

This is a familiar refrain: when renewables fail to deliver, relatively clean natural gas utility generation is ditched for “distributed diesel” generation which is inefficient, difficult to regulate, and only marginally cleaner than coal.

Roger Arnold's picture
Roger Arnold on Jul 9, 2014 7:07 am GMT

I’m feeling grumpy today, and I’m going to respond more harshly than I might at some other time.  More harshly, in all likelyhood, than what Christine deserves.  Nothing personal intended.

This article reflects what I call the “tinkerbelle view” of the smart grid.  Just sprinkle magic pixie dust and neat phrases like “situational awareness” and “microgrid” and wonderful things will happen.

Reality check #1: losses in the transmission and distribution system are not particularly large to begin with, and are far smaller than the “losses” that are incurred by using less efficient small distributed generators.

In terms of kilowatt-hours delivered to users per thousand Btu’s of fuel energy, the typical “inefficient centralized grid” will do twice as well as the typical DG solution. Natural gas turbines for the commercial DG market manage maybe 26% for thermal efficiency.  Even at that, the units are too large and too expensive for residential use.  They make sense for industrial or commercial customers who have special needs for backup power or process heat, but that’s a limited market.

DG advocates will counter the efficiency argument by extolling the virtues of CHP — combined heat and power.  “100% efficiency!”  100% of the energy in the fuel utilized!  Never mind that it’s at best only 25% for electricity and 75% for low grade heat that may or may not really be needed.  Low grade heat is almost entirely used for space heating or for hot water. For space heating, insulation is usually a more efficient solution.  Most commercial buildings are adequately heated by the waste heat of lights, motors and electronics, and human bodies.  Residential buildings in cold weather areas that can’t be upgraded for passive solar do need space heating, but even then there are at least two technologies that beat CHP.  One is geothermal heat pumping, and the other is district heating and cooling.

Of course that’s for “on demand” DG that’s necessarily based on burning fuel.  If what we’re actually talking about is rooftop solar, that’s a different kettle of fish. But it’s a little misleading to refer to that as DG. It’s not generation on demand, and in practice, it’s absolutely dependent on a robust wide area grid. Not one rooftop system in a hundred is installed with the kind of battery backup and power transfer switch that would allow it to continue supplying power when its grid connection goes down. The reason?  It’s a considerable added cost, and most customers don’t see it as worth the price.

Now about the “situational awareness” and DR voodoo:

Reality Check #2: grid operators already have full visibility on the power flow through their system, down to the level of small distribution stations.  That’s provided by their real-time SCADA systems (System Control and Data Acquisition).  It’s not at all clear what benefit there would be from extending real-time visibility down to the level of individual households.  Maybe checking for who’s awake at night, and selling the information to operators of call centers so they can target shift workers and insomniacs?

As to DR, I’m for it — but with a big caveat.  What’s been implemented to date (in areas where it has been implemente at all) is primarily an emergency response system.  It’s employed as a last resort to forestall rolling blackouts.  It’s not designed for and isn’t well suited to load balancing. For DR to work well for accommodating the uncontrolled variability of wind and solar resources, it requires a large installed base of discretionary loads.  A discretionary load is one that has substantial latitude as to the timing and level of its operation.  It must be able to choose when it operates based on signals that reflect grid status.  In most cases, new equipment is needed.  It will invariably be at lease somewhat more expensive than what it replaces.

That’s as much as I care to write for one comment.  There’s plenty more I could write about the issues raised in the article, but I’ll leave those points for others to address, or write separate comments later.

(FWIW, having written all of this, I now find I’m not feeling so grumpy.  No urge to kick the dog.  Thanks, Christine.)

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