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Going High-Tech With an Induction Cooktop

Induction cooktops respond quickly, avoid gas combustion, are tops in energy efficiency, and limit risk of burns

Posted on Mar 13 2014 by Alex Wilson

One of our early decisions in the planning for our farmhouse renovation/re-build was to avoid any fossil fuels. If the State of Vermont can have a goal to shift 90% of our energy consumption to renewable sources by 2050, we should be able to demonstrate 100% renewables for our house today.

That decision meant using electricity, rather than propane, for cooking. Electric cooking was actually a very easy decision for us. Roughly 25 years ago, when our daughters were very young, my wife and I replaced our gas range with a smooth-top electric range. I had read too many articles about health risks of open combustion in houses; I didn’t want to expose our children to those combustion products.

And I knew that even the best outside-venting range hoods don’t remove all of the combustion products generated when cooking with gas.

Deciding on induction

We were surprised back in the late ’80s how quickly we adjusted to an electric cooktop. It’s not as controllable as gas, but we made do just fine for 25 years. Nonetheless, friends always complained about electric cooktops being too slow or not controllable enough, so we wanted to try out the electric option that top chefs are increasingly turning to: induction.

So, for our new house we bought a KitchenAid induction cooktop for our kitchen island. I had wanted to go with the technology leader, Miele, but at about $2,500 for Miele’s 30-inch model, the cost was just too high for our budget. Even the much less expensive KitchenAid version stretched our budget considerably.

What is induction?

Without getting into too much physics, induction (electromagnetic induction), which was discovered in the early 1800s by Michael Faraday, is the process in which a circuit with alternating current (AC) flowing through it induces current in a material placed nearby. It is key to the functioning of induction (asynchronous) motors and most electric generators.

In the case of induction cooking, there’s an electric coil under the glass surface of the cooktop through which AC electricity flows. This current, in turn, generates current in a ferrous metal (iron or steel) pan that’s very close to it (separated by the glass cooktop). Electromagnetic current flows through the bottom of the pan, but because iron and steel aren’t very good electrical conductors, that electric current is converted into heat. In physics lingo, that’s electric resistance heat (since the material resists the flow of electric current).

The result is that the pan or skillet heats up and transfers that heat to whatever is being cooked. So, in effect, the pan becomes the heat source.

If you have a rice cooker, you’re probably already using induction cooking, since that’s how most rice cookers work.

Advantages of induction cooking

Speed and controllability. Because the pan generates the heat directly, induction cooking is very fast — heating up immediately when turned on and cooling down immediately when the current is reduced or turned off. Heat output can be adjusted even more quickly than with gas burners.

Energy efficiency. Induction cooktops are the most efficient of any option. According to a study done by Lawrence Berkeley National Laboratory for the U.S. Department of Energy, gas cooktops are about 40% efficient, electric-coil and standard smooth-top electric cooktops are 74% efficient, and induction cooktops are 84% efficient (see Table 1.7, page 1-22). Before you get all excited, though, be aware that cooking accounts for less than 3% of average household energy consumption — so don’t expect an attractive payback for the extra cost of an induction cooktop!

Less waste heat. Another aspect of that energy efficiency is greater summertime comfort. We’ve only been in our house for a couple months so haven’t used it in hot weather (that’s for sure!), but a friend who has an induction cooktop raves about the summertime benefit of not heating up his kitchen as much as he used to with a gas cooktop.

Safety. Induction cooktops, like other electric cooking elements, avoid combustion and gas lines, so are inherently safer than gas burners. But induction cooktops go further, dropping a piece of paper on a cooktop that’s on can’t cause a fire. In fact, as shown in the photo, you can cook with a piece of paper between the cooktop and the pot (though doing so probably isn’t a good idea). The electromagnetic induction happens through the paper.

Drawbacks of induction cooktops

Ferrous metal cooking vessels required. Aluminum, copper, and some stainless steel cookware won’t work, so buyers of induction cooktops may have to invest in new pots and pans. Use a magnet; if it sticks to the bottom of the pot, it will work on an induction cooktop. Fortunately, there are lots of options, including plenty that are reasonably affordable.

High cost. While the cost of induction cooktops has dropped in the last few years, they are still pricey. We spent $1,400 on our 30-inch KitchenAid Architect Series II induction cooktop, and the list price of that model is $1,849. A comparable KitchenAid standard electric cooktop (non-induction) lists for $1,299. The high cost of induction today is partly because of the induction technology, and partly because induction is only available in the high-end product lines from appliance manufacturers. I think the cost will come down and induction gains popularity and spreads into lower-priced product lines.

Health concerns? There is some concern that the electromagnetic fields (EMFs) created by induction cooktops could be hazardous. I understand that the field drops off (attenuates) very quickly with distance from the cooktop, though I haven’t borrowed a gauss meter to actually measure EMFs from our cooktop. I haven’t read credible reports of health problems from induction cooking, but discovering a problem can’t be ruled out.

The bottom line

I like our induction cooktop a lot. I’ve only had one frustrating experience: the time last month when I set out to make a big batch of chili for an office gathering and discovered that the largest of the skillets in our cookware set doesn’t work with induction elements, even though all the others do. I’m assuming that because the diameter of that pan is so large, the manufacturer used a disk of aluminum or copper, rather than steel, to conduct the heat to the edges more evenly.

Overall, my wife and I are very pleased with induction, though it does take some getting used to. We got a rimless model, and the black ceramic-glass surface blends in quite well with the black Richlite countertop material.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.


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  1. Alex Wilson
1.
Thu, 03/13/2014 - 10:05

One other drawback
by Matt Dirksen

Helpful? 0

We have had a GE Profile induction range for a few years now. Being a "new" technology at the time, we got the extended warranty on it. A couple years ago, we noticed that the large burner was not quite heating the pans up evenly, so we called the warranty service to have a technician come out to fix the problem. I was very explicit on the phone that it was an INDUCTION range, so we needed someone experienced with fixing it. It took three different technicians over a period of several months before we got the appropriate service.

Other than that, it has been a joy to use. It is especially comforting to watch the kids learn how to safely cook on it.


2.
Thu, 03/13/2014 - 10:40

Reliability
by Aaron Gatzke

Helpful? 0

Hi Alex,
Did you research or enquire about the reliability of induction cooktops? I have heard that they are packed with electronics under the ceramic top. That is why the extended warranty is so important because it could cost an arm and a leg to repair.
Any facts or statistics to report?
Thanks,
Aaron


3.
Thu, 03/13/2014 - 11:37

How can grid electricity be considered "renewable energy"
by flitch plate

Helpful? 0

Could be I don't actually understand what "renewable energy" is.

How is it that natural gas and propane are not renewable while electricity is? Natural gas reserves in the US and worldwide are enormous and uncounted. There is no shortage of fossil fuels; only man-made shortages in their supply.

Coal of course is also a fossil fuel and its likely your electricity is made from burning coal or oil to make steam to run turbines. But if not, its made from turbines run from water on rivers that have been dammed. I am not sure how river water can be considered anymore renewable than fossil fuels.


4.
Thu, 03/13/2014 - 12:23

Induction Tops
by Michael Lynskey

Helpful? 0

We installed an induction top for basically the same reasons i.e. minimize internal combustion sources (although we heat using a masonry heater), and to maximize the potential to move to electicity as we can generate this ourselves through solar (renewable). We have had one "burner" fail but company (IKEA) were very good at replaing the unit. Find it great to cook on too.


5.
Thu, 03/13/2014 - 12:33

Faraday's Law of electromagnetic induction
by Allison A. Bailes III, PhD, GBA Advisor

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Nice job explaining Faraday's Law, Alex! For those who want to see a really cool demo of this and a glimpse of the lab where Faraday made the discovery, check out this video:

http://youtu.be/txmKr69jGBk


6.
Thu, 03/13/2014 - 12:57

Glasstop
by Frank R.

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One question. As an owner of a glasstop electric range, I cannot stand the difficulty of cleaning the glasstop. I know they are advertised as being "easy" to clean, but in my experience they are a pain. Stuff spills out of a pan and burns onto the glasstop. We wipe off the glass top, use the goopy glasstop cleaner or use a razor. It's a complete pain to clean up. But with induction, do you still have the same problems? Does food burn onto the glass? Or does it wipe of easily?


7.
Thu, 03/13/2014 - 13:24

What is the amp/ watt draw
by Dave Cummings

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What is the amp/ watt draw difference between conventional electric cooktop and induction cooktop? Do you use electric or gas for the oven?


8.
Thu, 03/13/2014 - 16:09

Glasstop cleaning with induction
by Matt Dirksen

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Frank,

Because the induction system doesn't actually heat the glass, any spills that land on the top are VERY easy to clean off (primarily due to the fact that the food lands in areas outside of where the pan is resting, where the glass surface is essentially cool to the touch.) Even if you were to lift the pan up and pour food directly onto the surface under it, the glass surface is still considerably lower in temperature than the pan itself.

Ours is several years old and looks (almost) as good as it did when we first got it.


9.
Thu, 03/13/2014 - 22:52

Grid electricity renewable?
by Alex Wilson

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Fitch plate,
I consider the electricity "renewable" because our solar-electric system should produce as much electricity as we consume on an annual basis (net-zero-energy). The electrons we use aren't the ones we generate, however, and we will use a lot more than we produce in the winter months--but on an annual basis our intent is to be net-zero-energy.


10.
Fri, 03/14/2014 - 11:05

about costs...
by Jin Kazama

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surely, you all know that induction has been used in most europa for quite some time.
The prices there of even the high end model are much lower than the ones we pay here.
As always, we are getting "ripped" by the industry.

As an example, i've purchased from France about 5 years ago, Siemens induction 60cm width
high end model induction ( don't recall all details..but it was considered one of the best )
for ~ 800$CAD back then. Purchased matched vitro domino and grill units .
With UPS shipping and all 3 units , it came up to the same price as purchasing a 4 place Bosch unit 5 years ago.

The only thing was to verify that the unit was going to work on our 60hz, which i did for this particular model ( contacted Siemens UK ).

I hate getting ripped off, and i am glad prices have come down for this tech,
but still some way to go.

http://www.etrouvetout.com/electromenager/table-cuisson/table-cuisson-in...

have fun crying over the price difference even with the current high exchange rate!

Lastly,
it was about time we ( NA ) start using induction efficiency for cooking.


11.
Fri, 03/14/2014 - 11:07

lol
by Jin Kazama

Helpful? 0

http://www.etrouvetout.com/siemens-table-cuisson-induction-eh601fk17e-eh...
this is the new model of the one i purchased 5 years ago and works on 60hz.


12.
Fri, 03/14/2014 - 11:10

no offence ..
by flitch plate

Helpful? 0

I presume you mean you're inter-tied?

But this logic is cracked. Not you Alex, but the system we have created and the double talk we use to designate what is green and sustainable. Just like XPS foam being the most oft recommended insulation at "GreenBuildingAdvisor".


13.
Fri, 03/14/2014 - 16:12

stove ?
by flitch plate

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...is that an Jotul F100 in the corner? Nice detail and light in your place.


14.
Fri, 03/14/2014 - 18:07

An answer for fitch plate comments in response #3.
by Dana Dorsett

Helpful? 0

In Alex's case there is a substantial PV solar array providing much of the instantaneous power, and is in a local grid with small but growing wind input, and substantial wood-biomass input. He may or may not be paying on a PPA (or utility-bundled surcharge for PPAs) for 100% wind or something.

Being in the ISO-NE grid the regional grid average is currently about 8-10% non-hydro renewables on an annualized basis (over the past 5 minutes it was just 9%, to coals 13% it will likely have changed by the time you click the link: http://isoexpress.iso-ne.com/guest-hub;jsessionid=66C85B665DFB116ABFFFDE... ), and only about 12% coal fired on an annualized basis. By 2020 the coal fraction will be at-best on-par with offshore wind (currently 0%) after the MA and RI wind farms currently under construction go online.

Onshore wind resources in the ISO-NE region aren't great, but still good enough to have a lifecycle cost on par with coal at current pricing, if just a smidge behind combined-cycle gas at $5MMBTU well head pricing, and it's a growing input (over the past 5 minutes on-shore wind was carrying 1.5% of the load for the region. Five years ago it never even registered.)

And the PV boom in New England is still at the thin edge of the wedge, but experiencing exponential growth doubling in capacity every two years, in no small part due to the fact that the lifecycle cost of PV power has now dipped below the residential retail rate, even without subsidy, and subsidized in a variety of ways by different states and utilities within the ISO-NE grid.

Wind and solar are quite renewable, and don't eat into water resources the way thermal plants do, and will be carrying most of the regional load by 2030 if current growth trends continue. Natural gas will go broke at the most recent 3-year average due to the high costs of drilling for tight gas, coal is too expensive to extract at a cost that competes with utilty scale wind without doing damage far worse than hydro, without even getting into the atmospheric carbon issues. As the cost of the renewables continues to fall it becomes sufficiently cheaper than any power generation with a fuel cost, it will eat into the capacity factors of both nukes & gas. Coal is all but toast at this point in New England, and barring a huge crash in the cost of coal it'll be completely done by 2040.

The cost of distributed grid power storage is crashing at a rate comparable to solar, with even cheaper technologies on the 3 year horizon. The Ambri liquid metal batteries are dirt-cheap to make and look to be quite scalable- a fraction of the per kwh cost of other rapid response battery technologies- we'll see fairly quickly how well they fare in the field, but they are just one of many players in the storage market. ABB has a significant installed base across many technologies operating in Europe.

Add it all up and within the lifecycle of that cooktop the grid architecture and methods of control in this region will have changed dramatically with strong uptick in the non-hydro renewables fraction.

But sure, without a PPA in place to get his grid power from a renewables provider, the peak power and nighttime power at Alex's place may not be renewable, despite the net-zero aspect of the amount of grid power he is sourcing to the grid relative to his annual use.


15.
Fri, 03/14/2014 - 19:06

Edited Fri, 03/14/2014 - 19:22.

All electric houses and nuclear power
by Robert Connor

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With all the all-electric homes you advisors seem to like, what is going to happen when they shut down Vermont Yankee. I can't think of a worst place to do that than Vermont - where it is so cold and people cook (and probably dry and heat water and run those mini split heat pumps) electrically. Don't you people need all the electricity you can get?


16.
Sat, 03/15/2014 - 06:45

Jotul wood stove
by Alex Wilson

Helpful? 0

Fitch Plate,
Yes, that's a Jotul F100 (better photo attached). With such a low heating load, I wanted a small wood stove, but still one with a glass front. We decided on the F100. But it looked so small on the slate floor that we raised it somewhat on the bluestone hearth (which is supported by a granite step split in half). So far, we've only fired the stove up seven or eight times, but it's nice to know we have that back-up in case we lose power to our otherwise all-electric house or need extra heat in really cold weather.

Interior_1032_MedRes.jpg


17.
Sat, 03/15/2014 - 11:55

me too
by flitch plate

Helpful? 0

I just took delivery of my new F100 two weeks ago. I see you located it so the chimney exits the roof close to the ridge. Here is a great website on stove performance principles and correcting the many myths about wood stove performance.

www.woodheat.org


18.
Mon, 03/17/2014 - 11:41

Response to Robert Connor (#15)
by Dana Dorsett

Helpful? -1

In fact electricity demand growth in New England has been somewhere between flat and falling for a decade, and baseload demand (the fraction supplied by nukes) has been decidedly falling. Flat average demand with falling baseload demand has increased the peak-to-baseload ratio, but that is better met by distributed flexible resources than by inflexible impossible-to-ramp nukes:

http://www.eia.gov/electricity/monthly/update/images/NE_big.PNG

http://www.eia.gov/electricity/monthly/update/print_version.cfm

A small me of the flatness to the overall demand has been the fraction of the grid-source that is not directly visible to the ISO-NE grid operator on a real-time basis, namely the distributed generation that is on the customer's side of the meter, such as Alex's PV grid array, or on-site heat/power cogeneration. This grid input shows up as lower demand in the aggregate, but where there are per-kwh production credits/RECs that can be marketed in the NEPOOL some of it gets accounted for after the fact.

With the increase in smart-metering offering visibility of the real time clearing cost of peak power to the customer and the financial incentive for the customer to shed load the peak power loads can also be cut significantly. This "demand response" both contractual/ manual or automated has been increasing in recent years, and has proved quite useful in maintaining grid stability during the much more significant summertime peaks, as in this snap-shot of ISO-NE demand from June 2010:

http://www.eia.gov/todayinenergy/images/ele_load_curve.PNG

Demand-response nega-watts are the grid-equivalent of a rapid response peaking power generator, but has extremely small capitalization costs, and no transmission upgrade costs.

In short the answer to "Don't you people need all the electricity you can get?", is a decided no, the ISO-NE grid doesn't need all the electricity it can get. The growth in renewables on both sides of the meter as well as the more flexible combined cycle gas plants can MORE than cover any baseload shortfalls from the Vermont Yankee closing. The lifecycle per-kwh cost of distributed solar at 2012 prices was already at par with just the fuel costs of legacy nukes, and is well below just the fueling costs at 2014 PV pricing. Vermont Yankee has been producing on the order of~4% of all kwh going onto the ISO-NE grid in recent years. The installed capacity of PV (on both sides of the meter) is doubling about every 2 years in New England, (the stated of MA doubled it's cumulative capacity in 2013 alone: http://www.greentechmedia.com/articles/read/massachusetts-the-commonweal... ) and even considering the smaller capacity-factor of PV compared to nukes, new-PV is destined to reach the output-equivalent of building a Vermont Yankee every year before tapering off. The cost of that power will be below that of Vermont Yankee, and that is just part of the rationale for why keeping it open would be financial folly for both Entergy (the owner/operator) and the regional customer base.

In the 5 year time frame beginning Q1 2013, between Vermont Yankee and two large legacy coal plant retirements in MA the ISO-NE region will be retiring about 1.4 gigawatts of baseload generation, but in the same time frame will be adding about 1.2 gigawatts of new power generation, about half of it from combined-cycle gas, and a third of it from wind power (Cape Wind being a big chunk of the wind fraction.) Dispatchable biomass baseload power is another significant (and growing) fraction. The new-PV fraction is likely to beat both new-wind and new-gas for the new-capacity in the following five years, since it becomes simply cheaper than other generation sources for the utility operator, and well below retail on the customer's side of the meter. There's little question that PV would be able to cost-effectively supply more than 25% of all power in the ISO-NE with low-to-negative cost to transmission infrastructure costs, while the infrastructure costs for adding more combined cycle gas may inhibit it's growth going forward, and may prove more expensive than more-PV + grid-storage solutions for new generation sooner than currently assumed, which would increase the market share of renewables on new generation to well above it's current~50% status in the region.


19.
Mon, 03/17/2014 - 12:44

you don't need a huge unit
by Hobbit _

Helpful? 0

Single-plate induction cookers are fifty bucks from Amazon.
I got a Tatung TICT-1500TW which even came with a cheap pot
with a sufficiently ferrous bottom to work with it, and the
unit is awesome. I was referring to it as "oatmeal in thirty
seconds". It heats water in about half the time as a microwave,
in fact. Fully controllable -- the higher settings regulate
power sent to the induction coil, and the lower settings
cycle the minimum output at different duty ratios. I already
had enough old ferrous pots that I didn't have to change out
any cookware.

It works. I never fire up the old electric range it's sitting
on top of anymore. I can pull my completed dinner off the thing
and put my hand right down on the element with little risk of injury
or even discomfort. It plugs into an ordinary 120V outlet and as
its model number implies, draws 12 - 13 amps on full blast.

_H*


20.
Mon, 03/17/2014 - 15:00

About efficiency
by Eric Sandeen

Helpful? 0

The 40% for gas vs. 70-80% for electric probably doesn't take into account the (in)efficiency of whatever has produced and delivered that electricity to the point of use, right? So I'm not sure that's an apples to apples comparison; still, if you're going electric, the efficiency gain over a standard glasstop seems significant.

Did you happen to measure standby power for the unit?


21.
Mon, 03/17/2014 - 20:50

Source vs. site energy
by Alex Wilson

Helpful? 0

Eric,
Yes, good point. I am fairly sure that the efficiency numbers from LBNL are site energy—not factoring in the losses in power generation. Thanks for reminding us about that.

I haven't measured the standby loss from the induction cooktop, but I'm sure there is some, as there's a LED light on. I have an eMonitor24, but was limited to three 220V circuits, which are taken up by the Mitsubishi ASHP, GeoSpring HPWH, and Zehnder HRV. If I figure out a way to monitor some other 220V circuits I'd like to do so.


22.
Tue, 03/18/2014 - 14:00

Source efficiency of low/no-carb grid sources are irrelevant.
by Dana Dorsett

Helpful? -1

If the source is hydro/wind/nuke do you really care what the source-efficiency is?

I personally don't care if the hydro turbine was only running ~90% efficiency at the penstock, and with generator efficiency & transmission losses the gravitational-head to electric meter efficiency is in the mid-70s.

Nor do I care that the maximum (Betz's law) output efficiency of a wind turbine is ~59%, and that at typical or average operation after transmission losses the net efficiency of the kinetic energy of wind-to-electric meter is on the order of 30%.

Nor does it matter that the town's PV array on hill down the road is only 15% sun-to-DC, and after inverter & transmission losses comes in less than 10% efficiency from photons-to-electric-meter.

What matters to most of us is the lifecycle cost of the power, and the comparative environmental hits related to making & delivering that power.

Isolating that to atmospheric carbon damage...

On the ISO-NE grid about half the power is from low-carb sources, but the ~10-15% slice of the pie that is from 25-30% thermal coal makes the grid AVERAGE carbon footprint something similar to an all combined-cycle gas on a carbon/kwh basis. So from that point of view, when powered by today's existing grid the 70-80% induction burner is carbon-comparable to the 40% efficiency propane burner. But in 20 years it'll be doing a lot better than that propane burner as the grid carbon per delivered kwh is likely to have been cut by half, with no coal-fired plants, and the surge in renewables cutting into the market slice held by combined cycle gas & nukes.

It's not clear if the re-licensing of the rest of the ISO-NE nuke fleet will suffer the same fate as Vermont Yankee- the Pilgrim plant was just re-upped for another 20 years, but that doesn't mean it will continue to be economic to run it for that full period. When it turns off the sources that replace it matters, but the current constraints on the gas infrastructure in New England make me believe that at most half would be from more cc. gas. The San Onofre plant in CA had a license too, but after grossly expensive failed attempts to upgrade the facility it had to shut down permanently. In a tight capacity-market like southern CA it's now an open competition to figure out what is going to cover the potential peak capacity shortfall. The gas-power folks are lobbying hard with the regulators, but they are also being met with real challenges from the renewables and grid-storage crowd- the dust has yet to settle on that one despite the recent approval of this plan:

http://docs.cpuc.ca.gov/PublishedDocs/Published/G000/M088/K978/88978845.PDF

Since the actual plan details are dull & dense without context, a 1-page bloggery description with some background lives here:

http://www.greentechmedia.com/articles/read/cpucs-songs-decision-green-b...


23.
Thu, 03/20/2014 - 14:41

induction cooktops
by michael keesee

Helpful? 0

Alex, you forgot to mention another,serious drawback to induction cooktops - the cooktops large energy demand, several kilowatts per burner. As a researcher for SMUD (Saramento Municipal Utility District), I looked into induction cooktops as a potential energy efficient cooking technology. Although induction cooktops are more "energy efficient" than resistance electric cooktops, they have huge nstantaneous electrical demand, a major issue with electric utilities. You alluded to this issue in commenting on the site and source energy issues associated w/ induction cooking. You also failed to mentioned that gas cooking, as well as being cheaper is also more energy efficient both on a site and source energy basis. Finally even using on-site renewables to power your induction cooktop wouldn't make sense unless you had a gigantic PV system to supply the necessary wattage to power what is a relatively little used appliance, some thing we called load factor in the utility business. Combined with the high cost of induction, our European friends notwithstanding (oh, by the way how many Europeans have or use 6, 8 or 10 unit cooktops ! Not many), I concluded that induction cooktops are not an energy efficient option and should be avoided.
Even though I worked for an electric utility and believe that the path to zero energy homes is an largely an electric path, gas is sometimes the better, more environmental friendly choice.

But don't trust me. Ask the manufacturers, "what's the peak demand" of their products?


24.
Thu, 03/20/2014 - 15:02

Edited Thu, 03/20/2014 - 15:05.

Response to Michael Keesee
by Martin Holladay, GBA Advisor

Helpful? 0

Michael,
The last time GBA published an article on induction cooktops -- I'm thinking of Marc Rosenbaum's 2012 article on the topic -- you published a similar comment. Back then, John Semmelhack responded to your comment, challenging your alarmist scenario and providing peak load data from his own house to back up his position.

I'm not sure who's right here. But in areas of the country without access to natural gas (including most of Vermont and Maine, for example), most people use electric-resistance stoves to cook their food, and these appliances aren't causing any noticeable problems for electric utilities. Since induction cooktops use even less electricity than electric-resistance cooktops, my instinct is to side with John Semmelhack in this debate.

One final point: energy used for cooking amounts to between 3% and 4% of residential energy use -- meaning that this entire debate is probably a tempest in a teapot.


25.
Thu, 03/20/2014 - 15:09

The peak demand issues are getting dulled...
by Dana Dorsett

Helpful? 0

It's a moving target, but there are both production and load peaks more serious than induction cookers to manage in CA. In Sacramento under California's recently mandated distributed grid storage are intened to manage both the peak PV output and load peaking of electric car chargers, both of which dwarf the induction cooker issues. In the aggregate the peak grid loads from induction ranges are slightly lower than that of standard electric ranges, but miniscule compared to the anticipated loads of an electrified automotive fleet. There will be both grid-storage and smart-grid management of these loads, but it would be surprising if the distributed storage couldn't also manage replacing large numbers of gas cooking appliances at a lower net carbon footprint, etc. The grid-storage party is really just getting started.

Which side of the meter as well as who owns the storage lives on will vary too. Under the CA mandate the utilities are allowed to hold a maximum of 50% of all the grid storage. The details of how to equitably charge/compensate homes or industries for grid storage located on the ratepayer side of the meter are still being worked out. Utilities who own peaking generation are reluctant to have ratepayers charging their storage at off-peak retail rates only to sell it back to the utility at spot-market peak, but maybe they shouldn't be if that reduces their own capital costs. The net benefit to the ratepayers is there no matter who owns the storage. The stakeholders who lose are peak generation operators/owners who will see their capacity factors diminished along with their gross margin on (presumably now lower) spot-market peak pricing- everybody else wins.


26.
Fri, 03/21/2014 - 10:57

induction cooktop
by alan abrams

Helpful? 0

one additional advantage of induction cooking in humid climates: in contrast to any mode of electrical cooking, burning natural gas or propane releases water vapor, adding to the latent load of the house.


27.
Sat, 03/22/2014 - 15:00

I don't understand
by Robert Connor

Helpful? 0

Dana just what are you? It seems that the answers are so long and yet I can't figure them out. I asked about if Vermont needs electricity and where will it get it if enough people keep on buying all-electric kitchens. I think solar and wind can be enough for lights and computers and TV but for even an induction cooktop or anything that heats? A lot of New England areas don't have gas in residential areas so are stuck with electric (or a campfire).


28.
Tue, 03/25/2014 - 14:16

Edited Tue, 03/25/2014 - 14:17.

Induction and EMFs
by Christopher Vlcek, Littlewolf Architecture

Helpful? 0

I purchased a TENMARS meter to test our induction burners a while back. We have the same Kitchen Aid 5-burner 36" cooktop as Alex in one unit of our duplex, and a Frigidaire 30" range in the other. For both appliances at parboil, EMFs directly on the burner measure >1000mG (milligauss), but at an inch or two away they drop off to <5mG. For comparison, our toaster oven and hair dryer measure 10-150mG, again dropping rapidly at a distance of a few inches away. At what level should you be concerned? This site: http://www.baubiologie.de/downloads/english/richtwerte_2008_englisch.pdf suggests minimal concern for <1mG and severe concern for >500mG for prolonged (sleeping) exposure. Given that the EMFs are negligible at a distance of a few inches, I don't see a problem with induction burners.

I've found greater concern around ovens, that can measure 100-200mG at the top of the oven door. If you're working directly in front of the oven, that could be significant exposure right at reproductive level. But appliances vary widely, so it all depends on the particular unit.


29.
Tue, 03/25/2014 - 14:41

Too enginerdy? (Response to Robert Connor.)
by Dana Dorsett

Helpful? 0

I'm an electrical engineer by profession, but my degrees are in math & physics, but energy policy is one of my hobbies. ( I also have relatives in the electric-utility biz, though not in New England.)

" I think solar and wind can be enough for lights and computers and TV but for even an induction cooktop or anything that heats? "

Short answer, is yes, solar and wind will more than cover the miniscule fraction of load related to electric cooktops (induction or other). More importantly PV & wind will offset a large chunk of the already (much-larger than cooking loads) air conditioning peaks currently responsible for the annual maximum loads in this region. At current installation rates PV & wind will also for the growth in grid power from switching from propane/oil space heating to space heating leveraged by high-efficiency heat pumps. What's more it'll be both cheaper and more flexible than baseload nukes & thermal coal.

The longer answer follows:

The future output of distributed renewables and the amount of affordable distributed storage are currently underestimated by most people. Like most you are probably thinking of PV as both expensive and limited in output, but there is good analysis from credible sources that rooftop PV alone is capable of sourcing well over 20% of all kwh shipped on the ISO-NE grid by 2050, and at the accelerating rate of installation it may even get there decades before then. And it's more valuable/useful output than inflexible baseload generators like thermal coal & nukes:

PV output peaks during the daylight hours, hours when the grid load is high..

PV output peaks during the summer, when the air-conditioning demand is high. South facing PV peaks a couple hours before the maximum daily grid load peak on those days, but it only takes a modest amount of distributed grid storage to time-shift it into the peak demand hours.

During the night when demand is low nukes have to send a large fraction of the energy up the cooling stack to keep from over-sourcing the grid.

During hot weather when air conditioning demands are high, nukes have to throttle back to avoid overheating their cooling water sources (in the VT Yankee case, the Connecticut river)

Bottom line, a nuke's worth PV is more valuable to the ISO-NI grid than a nuke, which is too unresponsive to be able to track the hourly changes in grid load.

And there will be a more than a Vermont Yankee's-worth of PV coming on line in this region within the next decade.

At current PV pricing utility-scale solar is only slightly ahead of the wholesale price of electricity going onto the ISO-NE grid average price, and in less than five years it will be the cheapest grid power available. Even at small-scale PV pricing in NE the lifecycle cost is currently about 8 cents/kwh after incentives are applied, which is well below the residential retail cost in most of New England. By 2020 it'll be under 5 cents even without subsidies. Five minutes ago ISO-NE was paying over $88/Mwh (about 9 cents/kwh) for power: http://isoexpress.iso-ne.com/guest-hub;jsessionid=66C85B665DFB116ABFFFDE... (That website updates every 5 minutes- so clearly YMMV, but it's a moving target summertime peaks will sometimes hit over a buck a kwh under heavy air conditioning loads.)

At some point soon (right now, in many instances) people with reasonable shading factors on south facing roofs would be financially stupid to NOT put PV up as long as net-metering is allowed to continue. With the $0 down loan options or third party ownership lease deals it's never been easier to do, cutting the net annual expenses as soon as they throw the switch on a new installation. We're still at the thin edge of the wedge here, but the building tsunami of PV installation in New England is now inevitable.

PV alone will easily keep pace with change-over to induction cooking in VT (which is pretty slow, after all), and may keep up with electric cars for a decade or two, which is another currently tiny market that is poised for explosive growth as the per khw cost of lithium ion batteries crosses under $200, then under $100. Like PV, when the total cost drops below the cost of the alternatives, the market (and market awareness) begins to grow exponentially. Gasoline & diesel aren't likely to get cheaper, and electricity isn't likely to get much more expensive. The limiting factor for electric cars is battery size & cost- the maintenance and energy costs of electric cars is a fraction of that of the fossil-burners, and as the battery costs fall, the cost delta for the lower-maintenance-lower operating cost cars shrinks. At $100/kwh battery capacity it'll be a dead-obvious tipping point- another no-brainer kind of deal. (Tesla is projecting sub-$200/kwh batteries by 2020.)

The overall growth in power use on the grid in New England is not growing, but the absolute peak loads are. PV is part of the solution to that spiky peak issue, but so is grid storage, and contracted-for load shedding type demand-response (the utility pays large users to turn off/down their equipment for a few hours/minutes during critical load periods.) Whether overall growth in baseload kwh will pick up when more electric cars are plugging in remains to be seen, but some models suggest that it won't for at least a couple of decades. And the electric cars are going to be orders of magnitude more total power (both peak & average) than the impact of people switching their propane or gas ranges over to induction ranges. The solutions for the electric car issue will automatically fix any issues related to kitchen appliances.

This isn't some pie-in-sky vision of how it might play out, it's how it IS playing out in Germany, Hawaii, California, Texas, Arizona, places with either high electricity cost, high insolation levels, or both. By the time distributed renewables hits those levels in New England the strategies & hardware will be more mainstream than they are today. Grid assets are becoming smarter and more flexible, and the renewables are still seeing substantial year-on-year cost reductions. It's not a matter of "will" but of "when" flexible distributed renewables become the dominant grid source in New England. It's probably coming much sooner than you think.


30.
Sat, 06/21/2014 - 21:44

Induction cooktop
by Sandra Ostermeier

Helpful? 0

The induction cook top was a priority when I remodeled my kitchen 5 years ago. I can't express how wonderful it is! It's like electric gas -- VERY responsive to increases and decreases in heat. It does not heat up the kitchen; in fact, the only part that is really heated is the pan itself. It's very safe -- no flames or hot burners to expose yourself to. If the correct pan is not on the burner, it shuts off. I placed the cook top in the center of a 9 ft long 30" wide counter; a prep sink with a hose faucet is to its left which acts as a pot filler.

When I have parties, the sink is filled with ice and is the place for either cold salads or beverages, hot items are kept on the cook top, on low, and the remaining 36" to its right are put into service for other items and plates. It's great.

I also had a Jenn-Aire downdraft grille and cook top installed on an island adjacent. You would think this is all overkill, but I use them all...When cooking just for myself, I tend to use the induction cook top. When I move, I'll be sure to make room in my budget for the induction cook top.


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