Published on May 23rd, 2016 | by Guest Contributor


Fuel Switching: An Essential Step Towards A Decarbonized Future

May 23rd, 2016 by  

By Indradeep Ghosh, PhD
Cupertino, CA

About 80% of the world’s greenhouse gas (GHG) emissions are a direct or indirect result of extraction and burning of fossil fuels – a process that needs to stop to put the brakes on global climate change. The concept of fuel switching is simply the process of replacing dirty, non-renewable fossil fuels with clean, renewable fuels. Since most of the renewable fuel growth is happening in the electricity generation sector, it is obvious that the future clean fuel of the earth will be mostly electricity. There are mainly 4 major sectors which will undergo fuel switching to electricity in the coming years – transportation, industrial processes, commercial buildings, and residences.

In the transportation sector, this will mainly manifest in the adoption of electric vehicles (EVs) powered by renewable electricity and a maybe a small percentage of fuel-cell-based heavy vehicles powered by renewable hydrogen. The superior economics and driving dynamics of EVs as opposed to gasoline cars have been discussed on this site in numerous articles. In places like California, where I live, even with higher-than-average electricity prices, EVs make solid economic sense currently to fuel and maintain over their gasoline-powered cousins. Moreover, most utilities in the USA offer low time-of-use (TOU) EV charging rates which the owners can use to fuel their vehicles cheaply during the middle of the night when electricity demand on the grid is low. Due to these facts, fuel switching to EVs is almost a no-brainer even under currently low gasoline prices.

Other than for transportation, fossil fuels are directly used by consumers for generating heat. This article takes a closer look at the economics and hurdles of fuel switching in heating applications in the residential sector.

As fossil fuel and electricity prices vary all over, the world the analysis here is done assuming California prices in the Bay Area. Similar analysis can be done at any place once the cost of the prevailing fossil fuel and its replacement electricity is known. In the residential sector, the dominant heating applications are water heating, space heating, cooking, and clothes drying. Currently, in the Bay Area, more than 90% of households use natural gas to perform these functions. Though there are electrical replacements readily available in the market for each of these applications, it is quite difficult to make the economics work under current fuel prices.

There are two major hurdles for switching out these appliances in the residential sector. First, the operating costs of these electric appliances are often higher than their corresponding natural gas counterparts. Second, there can be considerable initial costs to replace existing gas appliances with newer electric ones because of upgrades required to the electrical wiring infrastructure of the house.

To investigate the operating costs hurdle, I collected energy efficiency data from the federal Energy Star site. I assumed that the most energy efficient gas and electric appliance will be used in the house irrespective of initial costs. This means that, for water heating, the popular gas storage water heater of maximum efficiency will be switched with a current maximum efficiency electric heat pump water heater. For space heating, a current maximum efficiency gas furnace will be switched to a maximum efficiency air source heat pump. Note that ground source heat pumps are purposefully ignored here due to the huge initial investments needed in installing these systems in urban settings. Also the milder weather in the Bay Area reduces most of the efficiency advantages of a ground source heat pump. For cooking, a gas cooktop is switched to an efficient electric induction cooktop. And finally, for drying, an efficient gas dryer is switched with an efficient electric heat pump dryer.

Over here, it is important to understand the concept of Energy Factor while comparing energy efficiency. It is the amount of energy obtained for heating purposes as opposed to the amount of energy spent in the appliance. In the case of gas appliances, this usually equates to efficiency and a value between 0 and 1. However, in the case of heat pumps, as they do not produce any heat but just move heat from one place to another, the amount of heating energy obtained is almost always higher than the electrical energy spent in the system leading to energy factors greater than 1. The findings are shown in the table below.

appliance efficiency

In the table, the cost of natural gas is assumed to be $1.2 per therm, and since each therm is equivalent to 29.3 kWh, it yields a per kWh energy cost of about 4¢/kWh.

It is evident from the table that, even though electric appliances are much more efficient than their corresponding gas counterparts, achieving operational cost parity is still a big challenge in the Bay Area, where the cheapest electricity rates from PG&E (Pacific Gas and Electric Company) run around 18¢/kWh for the flat-rate pricing. In fact, in the flat E1 rate offered by PG&E, none of the electric appliances can compete in operating costs with their corresponding gas counterparts. However, PG&E also offers some TOU rate schedules where rates can go as low at 11¢/kWh. If such rates are used, it is possible to make the economics work for space and water heating. Though it is conceivable to use TOU rates for water heating and store the heated water when electricity rates are low, it is quite difficult to do that for space heating. Also, the economics for switching cooking and drying are still quite bad, even though clothes drying can possibly take advantage of TOU rates.

One option for making the economics work is to pair the electric appliances with a net-metered solar system. Currently, in the Bay Area, solar PV systems can be installed for about $2/watt after federal tax credits, which translates to a levelized electricity cost of about 8¢/kWh. If this scheme is used, then electric water heating, space heating, and cooking immediately become economically viable in terms of operating costs. Even though drying is still costlier to run in electric mode, drying constitutes only a small percentage of the overall energy use if the other three applications are taken into account. So, the savings made by running the other appliances with electricity as well as the savings obtained by eliminating the gas meter connection fee make an all-electric home with solar completely financially viable in the Bay Area in terms of operating costs.

Other than the operating costs, there are the initial capital costs of switching these natural gas–based appliances to electricity, which can run into thousands of dollars. First of all, these high-efficiency electric appliances are similar in cost to top-of-the-line, high-end gas appliances. Even if the consumer elects to switch out the gas appliances at their end of life, there is an added burden of wiring infrastructure. Most of the older homes in the Bay Area are serviced by a 100 ampere main panel, which would be inadequate to service an all-electric home. The main electrical service panel needs to be switched to a 200 ampere panel at a minimum. (Note that this not an issue for the newer homes that come with a 200 ampere panel standard.) Also, multiple 240V lines need to be drawn from the panel to these appliances, further adding to the infrastructure costs.

The state and federal government can help in this process by providing energy-upgrade rebates to consumers who are willing to make the switch. PG&E can provide special rate schedules to all-electric homes to make the switch viable even for people without rooftop solar. Also, a carbon tax on the price of natural gas, which is at historic lows, will help in making the economics work better for consumers. The California Energy Commission (CEC), which has historically advocated for efficient natural gas based appliances, is currently looking into the issue of electrification of residential appliances – mainly the use of heat pumps. These findings should be reflected in the new Title 24 building code recommendations which are due to come out in 2019. It is well known that California is serious about reducing GHG emissions and the governor has set an aggressive goal for the state to reduce its carbon footprint by 2030. Ways and means to accelerate fuel switching should be an essential part of the plan.

(From the editor) Another story by Indradeep Ghosh I highly recommend: What It Takes To Create An Off-Grid Household In The Bay Area (California) Using Rooftop Solar & Battery Storage Only (Exclusive)

Indradeep Photo thumbAbout the Author: Indradeep Ghosh is a clean energy and sustainability advocate residing in the Bay Area, California. His life’s ultimate goal is to rid the world of fossil fuels and ensure a sustainable future in an Earth rich in biodiversity. He is a strong believer in technological solutions and the innovative power of humans to solve complex problems. He publishes his findings and experiences from time to time in CleanTechnica.

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  • heinbloed

    A very practical sample of fuel switching the Dutch “100% atom power ” company atoomstroon. nl has just performed.
    They went to the wall and the rest of their clients to a 100% RE seller…..

    (copied from )

    World’s last “100% atom power” clown bites the dust:

    The Dutch electricity retailer ‘Atoomstroom’ has given up last week.

    machine translation:

    The press release:

    machine translation:

    The Dutch atom clown’s last few clients are automatically transferred to “Budget Energy”, a 100% RE-retailer.
    According to Budget Energy’s disclaimer their power mix consists of 77% solar power and 23% wind power in 2015:

    machine translation:


    First they laugh, then they try to fight and then to join. But who invites Zombies for dinner …;)

  • dcard88

    100 amps not enough ? Frig – 5, micro – 10, oven – 20, AC – 40, water heater -10, lights – 1, electronics – 4 Dryer – 20
    That’s 110 amps, but your controller won’t let you run them all at once. Larger homes already have 200’s. The only issue is running your AC.

    • You forgot the 2 EVSEs each consuming 20 amps though mostly during late night when other appliances are off. Also the induction cooktop with all 4 burners used is another 20 amps. The heat pump sometimes cannot cope up with the heating and requires backup resistive heat to supplement. Then it alone can draw 35 amps. Same for the heat pump water heater – it can draw 20 amps when reverting to resistive heat in deep winter. I have a 150 A main breaker in a 200 A panel. I have survived without issues in my all -electric home for 5 years now.

    • Mike Dill

      OK, I live in Las Vegas, where the AC runs all the time. I have all of those, the Induction cooktop, and the EV. Being somewhat intelligent, I do not run the dryer at the same time as the cooktop and the oven, and I do not run the oven or microwave overnight when my EV is plugged in. My EV does not start to charge until 1:00 AM, when the dryer is done. I have a newer (SEER 18) AC unit that draws half of that figure that you stated, and my refrigerator draws 150W, but that is only when starting.

      Start with energy efficiency. Then think before just turning something on.

      • dcard88

        So you agree there should be no need for more than 100amp feeds for 90% of us?

        • Mike Dill

          I agree. If your house is properly insulated, has energy efficient appliances and is under 3000 SqFt (300 m2), you should be using less than 80A instantaneous max current draw. You are right that the AC or Heat Pump is the random big starting current, and can be an issue in extreme climates.

  • vensonata .

    From a purely economic view, PV alone is a better investment than virtually every form of heat pump, if and only if you have a suitable rooftop. The reason is that the lifespan of PV is double that of heat pumps. No mechanical failure or costly fixes are also an advantage. Electric resistance heaters are also cheap, simple and reliable. However in the big picture PV in winter, in large areas of the country, simply does not address heating demand. So the grid provides the usual carbon based energy. Net zero houses do not address real seasonal demand. That means that heat pumps are a good solution to seasonal deficits if we want to actually address carbon reduction.
    Of course, space heating demand should be at least partially addressed through insulation and air sealing. At the high end of the spectrum a well insulated house has about the same demand for space heat as it does for hot water. In the middle of the spectrum of house efficiency, one should at least aim for a 50% reduction in space heating demand from the pitiful average of American houses. Then add heat pumps and you have attained an 85% reduction. And yes, it costs money up front which, in most cases, needs to be borrowed. Is it worth it in the long run? Yes.

    • Freddy D

      You really can’t make these generalizations about space heating. Cold climates, and there are millions of homes in them, consume a huge amount of energy for space heating. Lots of people in the northern US spend thousands every year on heating. Building new construction to PassiveHaus type of standards would save homeowners and the economy a fortune and it would slash emissions. For existing construction on the north US heat pumps are the only feasible decarbonization alternative. Resistance uses 300% of the electricity as a heat pump. For moderate climates with sun perhaps different

      • vensonata .

        I don’t think we disagree about any of these points. However, people should be aware of the numbers when calculating heat pump savings vs PV return. Air source heat pumps for space heating in New England, if the cost of electricity is 18 cents kwh, break even about 12 – 15 years in. If the cost of electricity is lower, the pay back is longer. That is for air source direct wall penetration. For multi head, it is less economic. PV return is higher, almost double at present prices in the U.S.
        Remember that the heat pump is seasonal saving, the PV produces year round. A $6500 heat pump will save about 60% of the heating cost per year in cold climate U.S. Electric baseboard average costs in New England are about $900 year. So the heat pump will save you $540 year. A 12 year payback, but the lifespan of the heat pump may be only 15 years. So using a heat pump is a civic act to reduce carbon from the grid but not much of an economic device. Pv will both reduce carbon and is a better ROI. However, one needs the right rooftop for PV …whereas the heat pump can be installed almost anywhere.

        • Freddy D

          True enough. Depends on the house a great deal though. Lots of homes in the northwest burning 1000 gallons per year of fuel oil or $3000/ year. This would be for a 2,000 sq ft older home in NY/CT/MA with decent insulation added. Go with Mitsubishi or othe ductless, electric bills drop to $1,000/year. Saving $2,000/ year for a $15,000 investment – well over 10% return. Find that with a savings account anywhere. Electric resistance in this case would be more expensive than oil at $3,000-5,000 per year. Just an example I’ve seen play out several times in real life.

          And zero subsidies to make those numbers work.

          • Bob_Wallace

            This sounds like a place where some creative financing would be a help.
            A low interest loan that was paid back as part of the electricity bill. Set it up so that there was a significant monthly savings. Say, half the $2k savings goes to loan paydown, the owner gets the other half.

            Sounds like a good government program or a good way for electric utilities to grow their market.

          • neroden

            If you’re spending $15000 on a small ductless (such as is needed for a superinsulated house), you’re spending way too much.

            …so I assume you’re including the cost of the insulation and the labor associated with the insulation in the $15000.

          • Freddy D

            That’s for a 5 zone Mitsubishi big ductless unit including install in 5 rooms, outdoor unit, and running electrical. Equipment alone is about $8,500. And leaving insulation alone on a 60 to 100 year old house, a common age zone in the Northeast.

      • Karl the brewer

        It’s gobsmacking that housing specifications, particularly thinking UK here, still have a huge scope for improvement and yet nothing is done about it. As we all know every new house being built as I type will have to have NG gas ripped out and be retrofitted with heat pumps, better insulation, PV etc at some point in the not too distant future.

        And yet those in power prevaricate. It’s a massive scandal that the man on the street seems to be blissfully unaware of. We are being forced to buy houses with unnecessarily outdated specs when there are superior alternatives readily available.

        • Freddy D

          “We are being forced to buy houses with unnecessarily outdated specs when there are superior alternatives readily available”. Yes. And it will cost 1000% the cost – 10x – to retrofit later than it would have cost to build it right in the first place. And it won’t work as well.

        • Yes, “every … house being built .. will have to have NG ripped out”… The key problem is that home buyers focus on capital cost and don’t consider operational cost. Builders use NG since it has lower capital cost and thus keeps home “price” lower than the alternatives even though the smart financial decision would be to accept higher up-front cost in exchange for lower operational cost. The builder is done with the house once it is sold. The buyer spends a lifetime in the thing…

          Most home buyers are financially unsophisticated, thus, it isn’t surprising that they buy houses that are “more affordable” to buy but more “expensive” over time. The real shame is that banks, who finance these purchases and should understand the issues, don’t consider operational costs when approving mortgages. A less expensive HVAC system reduces a home buyer’s credit risk since it leaves them with more disposable income. Thus, banks *should* offer better interest rates to those who buy homes with more efficient HVAC.

    • The lifespan of PV is NOT double that of geothermal heat pumps. The heat pumps themselves should last 20 to 25 years and the pipes in the ground will have a life of at least 50 years. (Pipe warranties only go to 50 years. The oldest closed loop HDPE systems are about 35 years old and still working well.) A PV system starts to degrade the moment you install it and probably won’t last much more than 20 years. In any case, PV technology will have moved so far in the next 20 years, nobody is going to want to keep using today’s technology in 2036.

      • vensonata .

        Ahem, you need to do some reality based research regarding heat pump repairs, ground source heat pumps have long been subject to exaggerated claims both of efficiency and of durability. And your lifespan numbers on PV are way off. Many have 25 year warranties, some now have 30 year warranties and will certainly be producing over 80% at 40 years. Check out articles on Greenbuilding Advisor for close up reality checks on heat pumps, both air source and ground source. This topic has been hashed out quite well over the last 5 years.

        • Air source heat pumps have very short lifespan due to much of their equipment being exposed out-of-doors and due to corrosion of the surfaces of their heat exchangers. Geothermal heat pumps rely on equipment in the ground and inside buildings — no GHP equipment is exposed to the elements.

          The US Army estimates the useful life of ground source heat pumps at 40 years and of solar at 25 years… They estimate the life of traditional HVAC systems, including air-source heat pumps, at 20 years…
          See page 16 in:

          • heinbloed

            Estimates are for gamblers.

            Statistical research of in-situ installations from the shelf is still small.
            Fraunhofer ISE is looking at the matter and still searching for 100 guinea pigs:


          • vensonata .

            Ground loops may indeed last 50 years or more. The heat pump equipment is where the problem is. It is grossly overpriced. The inside pumps etc are actually simpler than air source and should be less expensive. However this is the fault of the HVAC industry for ground source heat pumps engaged in a “lying contest” with the air source heat pump industry. Both have inflated claims, blame well diggers and backhoe operators for costly installs when it is untrue. The “COP” numbers are devoid of “whole system” energy use calculations. The electricity for pumping is not included in GSHP claims. Testing over periods of 5 years often show declining efficiency as ground temperatures cool etc etc. In the end, perhaps at commercial scale, ground source is alright.
            The other hybrid form is air source with a single ground loop supplying pre-warming to a “heat recovery ventilator”. This keeps some of the earth warming advantage but is more economical than full ground loop excavation.

            As well, all heat pumps become less economically rational as super insulation decreases energy demand. At passive house levels heat pumps are net loss investments.
            I am not at all arguing against the use of heat pumps. However no one should think they are “going to save a fortune” by using them. They will probably break even over the long run, however heat pumps are an answer of sorts to the decarbonization of the grid…that is their real function.

    • neroden

      Insulation, air-sealing, and vapor-sealing is almost always the best investment. It lasts basically forever and has very very quick payback periods.

      I’ve ended up with higher hot water demand than space heat demand. This is leading to some quandaries and meaning I have to redesign my heating system (currently they’re both powered by natgas and the water heater is indirectly fired, but the system doesn’t handle this situation well and is overheating the house).

      • vensonata .

        Right you are. Super insulation is my favorite as it performs 24 hours a day 365 days a year for up to 100 years. No mechanical or plumbing, what could be more elegant? And of course when you close in on passive house standards (special U.S. branch of Passivhaus) then domestic hot water demand is about the same as space heat and cooling. And at that point heat pump savings are miniscule because saving 60% of $250 ain’t much.

  • Roger Lambert

    So, we have everyone recommending that ~ 60 – 70(?) million homes need $20,000+ in new heat pumps and $5000+ in water heaters and $30,000+ in deep energy improvements. And then $20,000+ in rooftop PV to make it ‘economical’.

    All this dumped on a middle-class which is fracking broke, and a NG supply which will run out in 30 years.

    Meanwhile, 90% of the folks here are against energy subsidies for established industries, still feel that “free” market solutions are best, and don’t see the value in community-produced excess hydrogen used for free home heating.

    Have I got that about right?

    • Freddy D

      Woven in there is a good point, but generally, no, that’s not correct. Energy efficiency upgrades have long been known to have “negative cost” – in other words the ROI is less than the cost of interest. Plus they get paid off over time and these buildings deliver decades of low cost service to their owners. The good point somewhere in there is that retrofits can certainly be badly engineered of badly selected for the application and end up costing more than they return.

      It’s not uncommon for well selected and well engineered energy efficiency improvements to have a 10 or 20% ROI. Try getting that in a savings account today.

      • Roger Lambert

        My point is that home heating “fuel switching” is a problem with catastrophic economic implications for at least half of American families. And, that means that they are going to keep on burning carbon as long as possible, which is really bad public policy.

        Thinking about the problem for about four seconds and recommending the bromides of gigantically costly upgrades with very long-term ROI’s is NOT addressing the larger issue. Don’t feel bad because at this forum, almost no one else does anything different!

        This is going to require some very large subsidies from the government for electric conversion; or some very innovative thinking re biofuels; or long-term planning re using excess RE generation to pump heat or hydrogen to communities. It would be good to start hard thinking about this now, rather than later.

        • Freddy D

          You’re right about that for sure. Retrofitting buildings is going to make EVs and electrifying the transportation fleet look very easy. The reason is simple: cars last about 20 years and buildings last about 100 years or more. Regardless of what’s “economically rational”, people go with what they can afford from today’s paycheck. Incentives and governance structures are incredibly important and very difficult to get agreement on.

        • neroden

          Well, if by “gigantically costly” you mean “extremely cheap” and if by “very long term ROI” you mean “2 months to 2 years”, then yes, but otherwise, no, Roger.

        • Whether or not replacing with heat pumps the fossil fuel heating in 135 million residential units and 7 million commercial buildings in the US will cost a great deal of money, we need accept that it is going to happen in the coming decades. Given the volatility of and inevitable increase in fossil fuel prices as well as our society’s growing unwillingness to accept the environmental impact of fuel combustion, it is inevitable that we will transition to heat pumps as the dominant technology for heating. This isn’t a “should happen,” this is a “will happen.” The only interesting questions are: How rapidly will the transition occur and how can we best manage the process?

          We used to heat with wood and dung, then we moved to coal in the early 1800’s. Towards the end of that century oil began to grow dominant. Then, in the mid-1900’s, natural gas took over and now electricity is on the rise. On May 6, 2016, the use of coal for heating in New York City became illegal. The number of homes using oil for heating peaked in about 1960. Natural gas peaked shortly after 1970. We’ve been moving from one heating fuel to another fairly rapidly over the last two hundred years. The move to heat pumps will be the last transition in active heating technology. In the future, we’ll be talking only about how to make more efficient heat pumps. In the end, Carnot wins…

    • Roger, If Geothermal Heat Pumps got the same tax incentives that solar gets, none of these costs would be an issue. As it stands now, GHP will lose *ALL* tax incentives at the end of 2016. Until the end of this year, GHP still only gets a 10% ITC while Solar gets 30%. It is no wonder that investors choose to invest in solar rather than alternatives…

      The big reason that we’ve seen growth in the solar industry but not in GHP or other renewables is that Congress has decided that they want it that way. If we had parity in the tax treatment of all renewable technologies, I am confident that you would see a great deal more than solar in the market. This would especially be the case if we awarded incentives based on results rather that just for choosing a particular technology. (Note: You get the 30% ITC for solar even if you install it in the shade and never generate a single watt of energy!!)

      • Roger Lambert

        Wow – that subsidy needs to be expanded, not ended.

    • neroden

      Roger, doing a serious top-quality full superinsulation retrofit on a typical house is typically under $20,000, much much less if you DIY…. and it has a payback period of, like, 2 years in utility bill savings.

      Air source heat pumps to cover a superinsulated house are under $5000, often as low as $2000.

      You have to buy a water heater anyway, and the heat pump water heaters cost about the same as any other water heater, maybe a couple of hundred dollars more; in a mild climate (where they aren’t increasing the heating load of the house) the payback is measured in *months*. Like, 1 or 2 months.

      Look up the actual prices before spewing on the internet, Roger.

      • Roger Lambert

        You are living in a dream world, neroden.
        – The Spewer

      • neroden, where do you live? For a $20,000 insulation job to have a “2 years” payback, you’d have to be spending $10,000/year on HVAC. Are you living somewhere with really extreme climate or do you live in a tent with open flaps? Most folk don’t spend $10k/year on HVAC and thus couldn’t dream of a “2 year” payback on a $20k job.

  • Jens Stubbe

    Fossil fuels responsible for 80% of GHG emissions! The man much be mad.

    Makes no sense at all because the GHG circulation in nature is factors higher..

    • I was talking about the excess here. The part which is in the natural carbon cycle is sustainable and should be maintained.

      • Jens Stubbe

        I still do not get it because this implies that nature contribute about 20% GHG emissions that somehow is in excess ?

        Or are you talking about farming and other human activities that increase the excess GHG by 20% ?

        • Right. 20% is mostly methane emissions from animal farming and agriculture. Methane is 25 times as potent as CO2 as a GHG. As we rear more and more animals for meat and milk, this excess methane is not being absorbed by the natural Carbon cycle.

        • neroden

          Deforestation should account for some of the 20%…

  • Armchair Hydrogeologist

    The very high marginal rates of PGE are due to a strange political decision made long ago to have a highly exaggerated incremental block pricing. It was started with good intentions during the rolling blackout era but now is on a path of its own pushed by a coalition of rooftop solar leasing companies and left wing politicians. It doesn’t reflect the true costs of the grid which are mostly fixed due to the distribution infrastructure being FAR more costly than the marginal local cost of electricity.

    The effect of this is that California has no heat pumps despite it being an obvious choice given the climate and the serious infrastructure risks of gas pipelines in a seismicly active area.

  • madflower

    The most important thing is we are starting to develop and refine the new technology. The transition will take a LONG time. NG gas in the lower48 is expected to run out in around 30 years. Right now NG is less then 2/mcf, and in 2005 it was above 13/mcf.

    It is a 30 year plan, and we are easing into it.

  • neroden

    I’ve found that gas dryers are kind of disappearing. Electric dryers are a much larger market, and as a result, the fancy, high-end dryers tend to come in electric only. Gas dryers cost more upfront but have *fewer* features.

    Also, the amount of money spent running the dryer is really quite low.

    So despite the fact that electric dryers cost more to operate, I think it will be quite possible to get people to switch. It’s already happening out of a form of inertia.

  • Any discussion of heating and cooling economics that focuses on a mild climate such as that in San Francisco is of minimal utility for the bulk of the rest of our country. Here in the Northeast, we not only have much more extreme weather, but we have a very high percentage of homes heated with oil or even electric resistance heating. In such an area and with those fuels, heat pumps are unquestionably the most economic HVAC solution — even geothermal heat pumps are easily justified. (Of course, no matter where you are, the environmental case for geothermal heat pumps is great. You must can’t get more efficient than “heat without fire.”)

    Here in New York State, only 20% of our greenhouse gases come from electricity generation, 30% come from heating fuel, and 40% from transportation. New York is also the largest consumer of oil for heating in the country. Thus, emissions from electricity are much less important to New Yorkers than they are to folk in California…

    The “Second Great Electrification” of our country will be driven by fuel switching, from fossil fuels to electricity, in the transportation and heating markets. We can’t meet our emissions reduction goals without ensuring that we broadly adopt these forms of “beneficial electrification.”

    • Freddy D

      Air source heat pumps have improved dramatically in the last 20 years and people in the northeast are having excellent results from air source heat pumps. This is particularly true for going from oil/radiator to ductless. For some strange reason, the US made air-source heat pumps vent the air out the top – the place where snow falls. All of the Asian units have vertical intake and exit surfaces.

      Northeast homeowners that I’ve talked with just love these ductless heat pumps with thei smaller costs and added AC in the summer.

      • neroden

        Big houses can’t go ductless (you’d need dozens) but it’s great for apartments.

        However, air-to-water split-system heat pumps finally exist, and for cold weather climates, too. I’m planning to get one as soon as I figure out how to locate it. This should allow hydronic-heating houses to use air-source heat pumps as well.

        • Freddy D

          yes, lots of options. One reason ductless systems are popular in the northeast are the hot water radiator systems which lack ductwork. Hence, retrofits are possible and not every room needs one, but your point is well taken. Central hot water heating heat pumps, regardless of air source or geothermal outside retrofit right into existing hot water heating systems. Hydronic is making a comeback for new construction too because it’s simply more comfortable heat.

          And we haven’t mentioned the huge benefits of deep-energy retrofits on homes in cold and very cold climates. That makes bills drop dramatically and gives more options for how to heat.

    • This article takes the relative efficiency and cost factors of fuel while looking at operating costs. Similar analysis can be done in the NE to figure out how much better air source or ground source heat pumps are over existing heating schemes. It does not matter what the total heating load for the season is from relative operating cost point of view. However, it will matter from the capital investment point of view as a high heating load leading to higher savings in operation costs will make the payback period of the initial investment shorter.

      • neroden

        This is a very California-specific article. For three reasons:
        (1) electricity prices are different in other locations
        (2) natgas prices are different in other locations
        (3) COP efficiencies depend on climate

        • True. Everybody has to make their own calculations but the method is the same. The Energy factor number published by EPA is an averaged COP for an average US climate and averaged over the year. However, in extreme climates these numbers will have to be modified.

          • Maybe you’d like to follow up with a similar analysis for New York? I think the majority of our US readers are in California, but surely a lot in New York & the Northeast as well.

            Would also be interesting to see this for the UK… 😀

          • Karl the brewer

            Yes please for the UK. I’m rubbish with a calculator.

  • Omega Centauri

    Should we call it fuel switching, or electrification?

    I think most of the time at least for heating and drying replacement happens when the old unit fails. Then it is a combination of what the repairmen recommend and minimizing the (unexpected) capital expense rather than longterm cost minization that determines the result.

    From what I’ve heard, electric (resistance) dryers have been gaining market share. How available are heat pump dryers, and heat pump water heaters? And what about the purchase price premium, can it be overcome by longterm savings?

    I have a portable induction cooker. We have a grand total on one pot that is suitable for it. Almost all the cookware for sale is nonmagnetic, so the issue of acquiring pots
    that are suitable could be an issue.

    • neroden

      You’re right about electric resistance dryers. I’ve been thinking about the reasons for this. Manufacturers don’t bother to make their nicest models in gas models any more.

      I think part of it is that gas dryers are more complicated and have to meet a lot more legal standards, because they’re a “combustion appliance” — electric dryers aren’t. They also have more difficult installation for the same reason.

      Gas dryers have always been a smaller market because a lot of places don’t *have* natgas. Being a smaller market, it’s not worth the manufacturers’ time to focus on them. Any new model is designed for the “mainstream” electric market, and if it’s a big hit, they *might* eventually make a gas variant. Which will cost more up front than the comparable electric dryer, which probably negates the savings on fuel cost.

      • The popularity as you said is highly dependent on the availability and cost of natural gas in a region. In the Bay area natural gas is relatively so cheap that all the big box retail stores like Home Depot and Lowes push gas dryers to the consumer. I sometimes just go window shopping to see what new efficient and smart appliances have come out and am dismayed to see that there are almost no electric dryers on the store floor. Even though the gas models cost a few hundred dollars more they make economic sense after 1 to 2 years of operation. All new house construction that I have seen here comes pre-plumbed with gas connection in the laundry area. This is sad but the reality here.

        • Omega Centauri

          Even with today’s California grid, a gas dryer will be better for the environment than a resistance heater one.

          Also I should note, any house I’ve ever lived in had 240volt outlet for the laundry room. Switching to a heat pump dryer should reduce the electrical needs, so that shouldn’t be a problem.

          Electrification is something that we should expect to take decades, too early electrification -especially with resistance heaters probably isn’t a good thing.

          • In terms of kWh a resistance dryer is slightly more efficient than a gas dryer. So unless the grid electricity is completely emission free it will make things worse. However, a heat pump dryer is twice as efficient. So if the grid electricity has low carbon intensity as in Bay area then it might improve things. I have to do the exact calculations with Pg&E’s latest carbon intensity numbers to see if the balance is already tilted. If the house has rooftop solar then off course it is better. Also there are cities like Palo Alto now with 100% carbon neutral electricity. In such cases it will improve things.

          • Omega Centauri

            Depends upon how you allocate the sources of the juice. Does the marginal KWhour run off the PV panels, or off the marginal supplier for the grid. At least short term I’d say the later, as the system operator has to find and bid for the extra KWhour. Maybe longer term the marginal increase in demand will lead to a marginal increase in new renewables gen.

          • True. If the marginal kWh comes from a peaker plant with 20% efficiency then it is bad for emissions. However, if it comes from a Combined Cycle Plant with 60% efficiency and is driving a heat pump dryer, then it might be better for emissions. TOU rates can steer people to do the drying during times of low carbon electricity. I do my drying during the day time on weekends and my solar panels directly juice the dryer. I have a large system though – 11.8 KW. The dryer peak draw is 5 KW,. During noon now the solar panels pump out 9.5 KW continuous. In winter it reduces to about 6.5 KW.

          • Freddy D

            Picking the californa example, the marginal Kwh comes from gas combined cycle. Gas dryer is more environmentally friendly now and probably will be for a decade or so. Heat pump for central heat, however, is a good idea anywhere in the country, plus as TOU pricing emerges on electricity, can take advantage of ample renewable power at certain times of day.

            Also, nearly everywhere, heating the building is a much bigger energy demand than the dryer.

          • juxx0r

            You guys have heard of solar powered air sourced clothes drying?

          • Esperiel

            Do you know offhand if there’s comparison of energy savings from using ultra-high speed spin-dryers? After taking clothes out of my old washer, the spin dryer would spin out cups of water easily every time. It made light fan assisted indoor air drying overnight or greatly reduced time mini wall-mount dryer very manageable for me before.

            (1) Reg. wash + resistance heat drying = 4kwh/10lbs [1]

            (2) Reg. wash + heat pump drying = 2kwh/10lbs [1]

            (3) Reg. wash + Ultra-high speed spin dry + resistance heat dryer = 1kwh / 10lbs [1]

            (4) Reg. wash + ultra-high-speed spin dry + heat pump drying = 0.5kwh / 10 lbs [1]

            with different dollar paybacks and thresholds for difference price sensitivity.

            Sample price segment decision combos:

            $<$200 (lifestyle optimization)

            $200 (add spin dryer)

            $2000 (better washer/dryer)

            $? (DIY insulation retrofit?)

            $20000 (add PV)

            $? (pro insulation retrofit?)


            [1] totally made up #s.

          • I do not know of any concrete data in this area. However, my 4.3 cu ft washer holds about 18 lbs of clothing at full. I spin it extra high to squeeze out the water. After that the resistive dryer takes about 4.5 kWh to dry it. The heat pump dryer will use about 2 kWh but take twice as long which is fine I think. We do 3 loads average per week. So with a heat pump dryer it is down to 300 kWh per year – less than 1 kWh per day. After that it is better to optimize other stuff like space and water heating.

          • Freddy D

            Lowest emission dryer today would be gas, certainly over electric resistance. Maybe heat pump dryers could be better, but then you’ve mined and refined a lot of incremental copper using diesel.

        • Wow, that’s crazy, and unfortunate.

          • Freddy D

            Well for the next decade at least, each marginal KWH in California results in 3kwh of natural gas burned at a combined cycle plant somewhere so maybe not so dire in the short term. But this doesn’t prepare for the future. Optimized emissions would install both connections in new construction and phase out gas when there’s enough renewable power.

        • neroden

          Well, Home Depot and Lowes offer strictly low-end models, which are usually available in gas. When I went shopping for a *fancy* dryer (dry your delicates, avoid wrinkles with steam injection, etc. etc.) I discovered that most of the manufacturers didn’t make the top end dryers in gas models at *all*. Obviously I wasn’t shopping at Home Depot or Lowes.

      • I honestly didn’t even realize gas dryers existed. 😛

        • bwollsch

          It all depends on where you live. They have gas driers, gas stoves, gas water heaters, gas furnaces and gas fireplaces.

    • neroden

      I would also say “Electrification” rather than Fuel Switching.

    • Marcel

      I don’t know where you live but it’s not difficult at all to find induction pots, even IKEA sells them.

    • Induction stoves seem to be all the rage here in Poland now. Seems most of the products on the market are. Can take a little bit of work to make sure you have pots & pans that can be used, but we haven’t had much trouble. As Marcel said, IKEA sells them, but it seems everyplace else does too.

      Seems that this would be the story in the US if it is here.

      • Freddy D

        Kitchen aid here in the US has a great infographic brochure showing how induction cooktops outperform gas cooktops in every attribute. Response time to heat, response time to cool, power output delivered to the food, and so on. Dispelling the myth (which I used to firmly believe) that gas is the best for cooking. (Can’t find it now though their Website not cooperating on phone browser)

        • neroden

          Actually, induction cooktops have a longer response time to heat and a longer response time to cool than gas cooktops — I’ve tested this empirically — so I don’t know what KitchenAid is smoking. It’s not significant enough for most people to care about for most types of cooking. The bigger problem is that induction cooktops only work with a small and limited set of pots and pans.

          • Freddy D

            Good to know. I haven’t used a Kitchen-aid induction, or many of them for that matter. They’ve been around for decades and are only now getting some awareness. Main selling point to date hasn’t been CO2 at all (we’re a tiny fraction of the population I think who thinks about this stuff), but rather how to get the best possible response time if there is no gas service in the location. Traditional electric cooktops are terrible to cook on.

          • Esperiel

            Full sized induction ranges w/ high power 3600w single element channel energy at remarkable rates (in contrast to 2400w 8″ large coil), additionally it’s focused into the cooking vessel rather than elsewhere + no NOx/CO (vs gas) ( –incidentally, maybe users should lean toward high smoke-point oils (e.g., safflower, ghee, refined avocado/olive) however to limit toxic oil smoke when high-temp frying +external exhaust hood.

            I got my friend to install one at their home instead of gas and they’ve been raving about it since (we all have a big potluck/bbq and kids over every week) and the child safety (low surface heat) and ease of cleaning (flat and rarely burnt residue since lowish surface temp) is a plus.
            I have an 1800w plugin ($60 sale at Costco) 115v programmable capacitive touch flat top that works remarkably well –esp. value-wise– (new editions arguably have finer gradation temp control and GE just came out w/ sous-vide capable model [albeit pricey].) It has steady temp; steady wattage; and timer; and cookware removal/overheat detection.

          • Esperiel

            Also check out Cooktek (professional induction cooktops $$) but high {powered, responsive, granular-temperature control}. Used at Alinea (highly rated restaurant) I adore and followed the construction of years ago (see:

    • Adrian

      Heat pump dryers in the US: There is one model from LG widely available via the two biggest home improvememt stores, it is expensive and it isn’t well-reviewed. More development needed.

      Heat pump water heaters are gaining ground and are generally well regarded.

      • neroden

        The problem with the current designs for both heat-pump dryers and heat-pump water heaters is that they suck heat and moisture out of the house.

        This ends up adding substantial load to the *home* heating system, and I’m pretty sure you end up less energy-efficient than before if you’re in a cold climate. In a warm climate, obviously, it’s great.

        • You get hot water “free” when you use a modern geothermal heat pump in cooling mode. Instead of dumping wasted heat into the outside air, the GHP uses your hot water tank as a heat sink. The result is a cool house and hot water. When in heating mode, the same system will use heat from the ground to produce hot water.

          Yes, using ASHP for hot water has all sorts of problems (like low efficiency and over-cooling your basement…), but you can’t generalize those problems to all heat pumps. ASHP and GHP are different technologies.

          On dryers… The problem is that we don’t have “clothes dryers,” we have “clothes ovens.” We bake our clothes when we should be dehumidifying them. To get drying right, we need to stop cooking clothes. For instance “utrasonic drying”:

  • sault

    This is why you should never believe anybody that uses primary energy consumption numbers when arguing against renewable energy. All the waste heat associated with combustion makes this figure way higher than what people actually need in terms of energy “services” like hot water, cold beer and turning the wheels of their car.

    • Frank

      Primary energy consumption? You mean when they compare energy inputs to electricity outputs? Take a steam turbine for example, where they compare the BTU’s in the electricity output from a CSP plant, to the BTU’s in the gas or coal. Why not compare it to the solar energy hitting the mirrors? That’s what’s heating the water.

      • sault

        While plant efficiency is important for cost factors, solar “fuel” is free and limitless. I was focusing on when people say the USA uses X amount of energy (in the form of primary energy) and then throw their hands up saying we’d need so many solar and wind plants that transitioning off of fossils and nuclear will be impossible.

        When you switch away from combustion, you don’t have to account for all the waste heat inherent in the process. So we ton’t have to replace the energy in each ton of coal, each TCF of gas or each barrel of oil one-for-one with electricity. We just have to replace the output of each power plant, car, industrial machine, appliance, etc. with a similar amount of electricity. When someone is trying to argue against renewables by falsely inflating energy consumption by using primary energy, then they are not debating in good faith.

        • Freddy D

          Furthermore, in heating buildings, what is the true useful energy need? Using PassiveHaus building codes, heating requirements drop to near zero, even in places like Minnesota and New Hampshire. And this construction is far cheaper than conventional construction plus heating costs.

          • sault

            True. The main problem to deploying these technologies is that the cost is paid up front while the savings via efficiency accrue over time. Sadly, most people can’t do the math to determine that even a 5-year payback on a lot of efficiency improvements is a really good deal.

          • Freddy D

            Sigh – yes the enemy of energy efficiency for decades. My Econ professors would have described this as “economically irrational behavior” and it happens everywhere.

          • neroden

            For reference, even with the best superinsulated statndards, the heating requirements for single-family homes with small numbers of residents (as opposed to apartment buildings — heat generated by the *occupants* is an important factor) in the really cold states is not really near zero. It’s roughly 10% of what other people are using, but it’s still enough to be significant.

          • Freddy D

            10% – and “heat generated by occupants” – exactly. One example of a guy in New Hampshire with a super-insulated home that would, under normal circumstances need a 200,000 btu/hour furnace in that climate, decided to go with a couple 1000 watt resistance baseboards on the first floor because the heat demand was so tiny. It simply wasn’t worth the capital cost of complicated heat pumps or furnaces when most of the heat needed came off the fridge, lighting, etc. Baseboards were only for the occasional boost.

            Another helpful aspect of very well insulated buildings is that when you do put heat in or take it out, they hold temperature pretty well for 10, 20 or 30 hours. Hence, you can heat/cool when renewable power / solar is cheap and in surplus. No need for storage contraptions, ice cooling / thermal mass / powerwalls etc.

        • Frank

          Honestly, I’m not even sure what that quads number is good for. That kind of thinking doesn’t even work with combustion if you are going from an old coal plant to a new GCC plant.

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