11 ms·
Right, the heat pump will reduce energy use to maybe 1/3 of a gas furnace, but natural gas is something like 6x cheaper for the same amount of energy, so it is
by bagels 3y ago
Right, the heat pump will reduce energy use to maybe 1/3 of a gas furnace, but natural gas is something like 6x cheaper for the same amount of energy, so it is an expensive folly.
If California is serious about this, they need to reign in the utilities to reduce prices and or stop the attacks on solar installation.
- tootie 3y ago> 6x cheaper It will have a lower price but not a lower cost. At this point we can't wait for price efficiency we have to pay whatever dollar amount to avoid the catastrophic human costs of burning fossil fuels.
- mullingitover 3y agoSouthern Cali resident here: I got a mini split system installed a couple years back, and last year's eye-popping surprise gas bill inspired me to start running it backward for heat instead of using the furnace. Pricewise, it's actually a wash. My electric bill went up by about $100 a month, whereas during the winter my gas bill was running about $100 a month to run the furnace (aside from that one random $600 bill one month last year that inspired this change). I've been using the mini split all winter and it's been great.
- CaliforniaKarl 3y agoThank you for posting that. Although the cost of electricity is important, when deciding on using a heat pump for heat, the big question is the cost of electricity for heating, relative to the cost of the fuel you are already using (natural gas, propane, oil, etc.). It's definitely annoying to calculate! Since a heat pump's efficiency can vary with the outside temperature, it takes a bit of work to estimate your potential added electricity cost.
- lazide 3y agoAlso cost of capital for installing the heat pump, if a new installation.
- mullingitover 3y agoTo me the heat was a freebie. I installed it for the AC, wasn't expecting to use it for heat at all.
- thelastgallon 3y agoIts a wash when gas prices are at historical lows: https://www.eia.gov/dnav/ng/hist/rngwhhdm.htm https://www.eia.gov/dnav/ng/hist/rngwhhdm.htm
- Spivak 3y agoThat isn't the table you actually care about because it doesn't hit the residential customer like that. The nominal $/therm in my area has been stable for the last 10 years which might be artificial but to my bank account it's all the same.
- Scoundreller 3y agoObviously depends where you are & your use, but most of the gas bills here are everything but the actual gas. Transportation, distribution, storage, taxes, standby charges...
- inferiorhuman 3y agoNatural gas prices have not remained stable in California. https://www.latimes.com/business/story/2023-01-06/get-ready-for-a-huge-socalgas-bill-this-month-as-natural-gas-prices-soar https://www.latimes.com/business/story/2023-01-06/get-ready-...
- raegis 3y agoI'm in southern California as well, and my gas bill in dollars per therm are not at historic lows. However, price per therm did not double this winter like it did last winter...so far.
- gnicholas 3y ago> stop the attacks on solar installation I've not heard of any attacks, just reductions in subsidies (tax credits, net metering). Can you share what you're referring to?
- KptMarchewa 3y agoRemoving those subsidies while keeping fossil fuel ones is kind of attack.
- TheOsiris 3y agoisn't that an attack? removing/reducing subsidies removes incentives for people to install more solar
- gnicholas 3y agoI don't generally view the removal of subsidies as being "attacks". I view that as the end of the free money.
- janpieterz 3y agoDepends how you see it. If you assume a neutral state of no incentives, adding benefits to stimulate growth and later removing this benefits once growth is achieved can be seen as "attacking this positive state" or simply "bringing back to neutral". I moved to SoCal recently and didn't realize things like net metering even existed, so when people started to rant about these new measures I was very surprised to learn about them, and especially about people presuming these things to be "normal".
- gnicholas 3y ago> when people started to rant about these new measures I was very surprised to learn about them, and especially about people presuming these things to be "normal". I think at first people were (reasonably) scared that net metering might go away with no grandfathering for existing installations. People had a reasonable reliance interest in maintaining at least some of their existing benefits for the payoff period of their panels. Once it was clear that existing installations would be grandfathered, I didn't hear much ranting anymore — just people who were bummed that a subsidy was going away (or people rushing to get in under the wire).
- exe34 3y agoIs there a reason heat pumps use electricity? I would have thought the same approach would work with gas - you only need to burn a fraction of the gas to drive the "fridge" backwards?
- colechristensen 3y agoYou seem to be missing something fundamental here, I’m not sure what it is. How do you think heat pumps work?
- Arrath 3y agoOP has a point, fundamentally you could drive the heat pump by a little gas turbine, or bridge the gap with a gas powered generator.
- theteapot 3y agoCombined Heat and Power (CHP) is big in Europe.
- exe34 3y agoWhat I had in mind was that heating and cooling using an air-conditioner, a fridge or a "heat pump" is fundamentally the same thing, and electricity is just one way of driving it. Ultimately you have a gas that you compress to release heat (outside for AC, inside for heat pump), which then expands (inside for A/C, outside for a heat pump). The compressor can run off a pedal bike for all it cares.
- david422 3y agoI think you are back to where you started. If it was cheaper to use gas to run a heat pump then everybody would just run generators in their houses off of gas instead of using electrical lines.
- bluGill 3y agoThat has been proposed. Well the proposal was to run a small engine powering a generator, then you cool the engine to heat the house, while the electric is sold (or otherwise powers the house). However modern gas furnaces are > 90% efficient and it is hard to get an engine that efficient for heat (remember the engine will be running indoors so it needs to not fill the house with noise of CO). I think no matter how you look at it, you can't make this system more efficient than just using the furnace to generate heat without the engine.
- colechristensen 3y agoUtilities cost excesses in California are largely PG&E paying for its liability for causing wildfires in places where people probably shouldn’t live anyway. For example Silicon Valley Power which serves Santa Clara (or something like that) has rates that are literally half as much as PG&E. In Minnesota I’m paying for Xcel Energy’s mistakes in Texas.
- s1artibartfast 3y agoPeople should be able to live wherever they want. That doesn't imply others should have to subsidize them doing so. It is really quite simple. If someone remote wants power, they should secure power and pay for it at a market clearing rate, given the cost and risk to deliver it.
- AnthonyMouse 3y agoThis is something else. California has wildfires, and climate change has made them worse. Then the people who built their houses in a silly place prone to wildfires watch them burn down. This is becoming a problem as the frequency which with it happens increases, because it can bankrupt fire insurance companies (who then can't pay claims), or make fire insurance there unaffordable and then people don't buy it, their house burns down, and you have angry constituents. The political solution to this is to put the liability on the power company whenever possible, even though it isn't really their fault. The fire is caused by dry conditions and that wood is going up the first time there is any kind of flame anywhere near it. If it wasn't PG&E it would have been a lightning strike or something else. Having the fires less often can actually make them worse. But the power company is a deep pocket, so if there is any way to pin the fire on them, that's what everybody wants to do, so that the uninsured people in the fire zone can collect from someone and the currently insured people who are still there don't become unable to afford fire insurance. Then the power company raises rates on everybody in their service area, including people who don't live in high fire risk areas, because the government has them acting as the fire insurance company, but now you can't cancel your "fire insurance" without turning off your electricity and it also has to be paid by people who didn't build their house in a silly place.
- GenerWork 3y ago>If California is serious about this, they need to reign in the utilities Why would they reign in one of the best ways to ensure that Calpers remains solvent?
- bagels 3y agoHow are they related? Investments in PGE, which has had poor returns?
- gregwebs 3y agoThere are second order effects from natural gas use in an actual furnace that aren't taken into account in price of energy comparisons. A furnace has to either 1) exhaust out air initially drawn from the house which must be replaced by cold outdoor air coming into the house (this requires more heating of the house) 2) take in fresh cold air for combustion and exhaust that (which requires extra energy to heat up the cold air)
- bluGill 3y agoAll modern furnaces I've seen take #2 - use air from outside. Despite that they can get to 99% efficient. It doesn't take much energy to heat up that cold air.
- giobox 3y agoMy experience in the US at least is that its not uncommon for the furnace air intake to draw air from inside the house (my last two homes in PNW as one example).
- zbrozek 3y agoCalifornia resident here. Both of my last two places with gas furnaces combust unconditioned air.
- CaliforniaKarl 3y agoThe furnace my parents (who live in Ohio) installed 10+ years ago uses outside air for combustion, not conditioned inside air. As it's older, it's not got a 99 AFUE, but it's high (I think in the low 90s).
- bluGill 3y agoThat used to be very common in the US, and there are a lot of old systems still working. However every new furnace I've seen is installed to use outside air. Using outside air needs $100 more in parts and labor and it prevents air balance issues in modern well sealed houses.
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- TheSoftwareGuy 3y agoOr, they could increase the price of natural gas (perhaps using a tax)
- newZWhoDis 3y agoThe point you’re missing is electricity should never be expensive, if it is then you’re doing something very stupid.
- Retric 3y agoIn the continental US you get ~2x the heat from burning natural gas in a combined cycle turbine to run a heat pump than you would from using a high efficiency gas furnace. The market price of electricity vs gas varies quite a bit through time and various distortions of the market. Currently gas is cheap, but you want to compare historical averages when buying something that lasts 15+ years not simply look at current rates.
- Aloha 3y agoI don't think your math adds up. Combined cycle is like at most 70% efficient, subtract 10% of distribution, you end up with 60%. At 50f my 5T heat pump takes 6.6 kWh to generate 50,000 BTU. 6 kWh of energy takes 71cf of gas to make - accounting for transmission and generation losses. 71cf of gas will make 71,000 BTU of heat, assuming an 80% efficiency furnace, that comes out to 56,000 BTU usable. Yes a heat pump will vastly outperform resistive strip heat - but not even an 80% gas furnace.
- stephen_g 3y agoWhat kind of system do you have that is only giving you (if I’ve converted the those very confusing units correctly) a COP of 2.2 at 10° C? That’s really very poor… There are air-to-water units that can achieve COP > 4 at 0° C, and even a good air-to-air should still be over COP 3… I’d expect to see a COP like that at -15° C or below on a modern unit…
- Retric 3y agoReplace your heat pump? People installing new heat pumps are going to see much higher efficiency. 50,000 BTU = 5.27528 * 10 ^ 7 J = 14.6 kWh / 6.6 kWh = COP of 2.2 at 50f which is absolutely terrible. Modern heat pumps should have a COP around 4 at those temperatures and 3 near freezing. Also, “Subtracting 10%” would mean your grid losses are 17%. “annual electricity transmission and distribution (T&D) losses averaged about 5% of the electricity transmitted and distributed in the United States in 2018 through 2022.” So, (70% * (1 - 5%)) = 66.5%, but resistive losses are reduced in the cold. https://www.eia.gov/tools/faqs/faq.php?id=105&t=3 https://www.eia.gov/tools/faqs/faq.php?id=105&t=3 4 * 0.665 = 2.66x though obviously what matters here is the annual average COP. (3 * 0.665) = 1.995 aka 2.
- smcleod 3y agoNatural gas won’t stay cheap. It was cheap here in Australia 10 years ago and now it’s so expensive no one can afford to run gas heating and it’s only going up. Now (thankfully) the government has banned the installation of new gas heating and a lot of people are getting rid of gas cooking, hot water heating etc… it’s for the best.
- maxglute 3y agoI remember a recent investor report posted on HN about declining health of permian basin, and the economics of extraction will increasingly not make sense in 10 years. Seems like no brainer if shale and by connection LNG is on way out. Might also explain Biden stalling LNG expansions especially with NATO on the hook, maybe it's cynical electioneering to his base, but maybe the future of cheap US LNG is not bright vs renewables.
- jhallenworld 3y agoThe fossil fuel capitalists are so very unhappy about this ban, they are still going on about it in the financial news. I have to say, I love it. Low natural gas prices directly benefit me, and isn't it our gas? The price has certainly come down (look at henry hub chart..), but also winter has not been too cold.. They should ban oil exports next.. (for "national security") Actually export tariffs would be better than outright bans.
- dripton 3y agoExport tariffs are actually unconstitutional in the US. https://en.wikipedia.org/wiki/Import-Export_Clause https://en.wikipedia.org/wiki/Import-Export_Clause
- jhallenworld 3y agoInteresting.. the same section banned any limitation on the importation of slaves... at least that clause had a sunset date. Both clauses were basically: "don't touch our cash cow".
- Areading314 3y agoSolar isn't a useful source of energy for heating in California, since the demand is almost entirely during winter mornings/evenings where the sun is down.
- bbarn 3y agoSolar with Battery storage is a very useful source for heating energy, even in the coldest climates in CA. Even in the mountains where it drops below freezing at night, most places it's still sunny a lot more than the US average during the day. Most Battery setups I know of target a 4 day stretch of cloud cover for storage capacity, so it is certainly an option. Where I live at 7000 feet, we have so much sunshine, even in winter, solar is a very viable option. Legislation removing people's ability to recoup the costs is the only reason it's not in every house in the city. The only option left is a much more costly battery setup.
- PaulDavisThe1st 3y agoWhere I live, at 6200 feet, we have oodles of sunshine. Even so, the air-source heat pumps in my old adobe use 3x more than we generate (which in turn is 3x more than we need during the summer). No (sane, residential) battery system can handle this. Which mostly goes to show the value and necessity for serious insulation and air-sealing, which this house does not have. Nevertheless, the point about batteries remains.
- adgjlsfhk1 3y agoCalifornia (and everywhere else) could make solar a lot more useful by making electricity cheaper from 10am to 3pm. If heat pumps and electric water heaters were set up to run more when the sun is out, it would noticeably decrease the evening spike in electricity demand.
- boringg 3y agoSolar takes demand out of the entire pie. So less natural gas needed during peak hours. Also move some of that excess in to energy storage and you can cover during that time in the morning.
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- nonethewiser 3y ago> If California is serious about this, they need to reign in the utilities to reduce prices and or stop the attacks on solar installation. Why do you think electricity prices are high?
- bagels 3y agoA combination of: mismanagement and corruption. To pay for all the people that PGE murdered with their negligence? Why do you think electricity prices are high? Why should the rates be 4x the rest of the country?
- nxm 3y agoBecause of regulations and higher costs (labor)
- nonethewiser 3y agoIf that were the case why would you continue to let PGE run the grid?
- nsfmc 3y agoi'm not sure if you're serious, but the california public utilities commision's public advocates office (what a mouthful) describes california's rates as generally higher than most of the nation[0], with southern california's rates being highest (with both increasing). you can see, for instance san diego's rates [1] which are $0.38/kWh in the winter and $0.48/kWh in the summer. for context, this means if i pay 11 dollars in electricity generation (because i'm part of a municipal electric generation coop), i'm still paying $36 for distribution/transmission/etc, which is $47 for 106kWh used or ~$.44/kWh which is roughly what electrify america charges ($.48/kWh) when i go to 'fill up my car.' as far as i can tell from talking to people, this is is more than most people anywhere in the country (including hawaii) pay for their electricity. [0]: https://www.publicadvocates.cpuc.ca.gov/-/media/cal-advocates-website/files/press-room/reports-and-analyses/230224-public-advocates-office-2022-electric-rates-report.pdf https://www.publicadvocates.cpuc.ca.gov/-/media/cal-advocate... [1]: https://www.sdge.com/sites/default/files/regulatory/1-1-24%20Schedule%20DR%20Total%20Rates%20Table.pdf https://www.sdge.com/sites/default/files/regulatory/1-1-24%2...
- michaelt 3y ago> stop the attacks on solar installation I don't know if the experience of a Brit with a roof covered in solar panels applies in California, but: during months when you want to run the heat pump, your solar won't be producing shit.
- scruple 3y agoIn Orange county, CA, we generated 16.6kWh today, on a 5.6kWh system, and it's been partially sunny with some sporadic rain storms.
- valenterry 3y agoModern great heatpumps, installed correctly, are rather between 5 and 7 in terms of COP. Also, even the best gas heating systems only achieve 90% efficiency. In other words, it either be very very very cold in your area, or you have to screw up the installation before gas has lower running(!) costs. Besides that, a gas power plant easily achieves 33% of efficiency for generating electricity from gas, rather 50% for the new ones. In other words, if the price for electricity is more than 3 times as high as gas, there is a high chance that it's due to tax, regulations, etc. Though, the price for maintaining a stronger power grid comes on top.
- naijaboiler 3y agoI dunno. My mom’s heating bills in Indiana using heat pumps with auxiliary electric heaters was >$700 month at electricity costing 11c/kwh. I live in Massachusetts where my electricity cost 33c/kwh. So if I used my mom’s heater to heat a house of similar size, my heating bill will be $2k/month. My heating gas bill is under 120/month. I understand a bulk of that cost comes from the aux resistive electric heater. But for really cold places, that’s needed when the heat pump can’t keep up or you need to rapidly warm the house. As is, we are still quite far from heat pumps being cost efficient as gas for places that get really cold
- valenterry 3y agoI don't think so. Check those measures for some example heatpump: https://www.eurovent-certification.com/en/catalog/program/certificate/participant/model/show/196539762 https://www.eurovent-certification.com/en/catalog/program/ce... They are not from the manufacturer but from an independent service that is used by various states that are members of the eu. As you can see, at -7 degrees celsius, the COP is still almost 4. So even at that temperature, this heatpump is still about twice as afficient as burning gas directly. Of course, it depends on the correct installation. It's easier to screw up the installation of a heat pump than a gas heating system. But it doesn't invalidate the theoretical bounds.
- naijaboiler 3y ago
- Schnitz 3y agoNatural gas prices have gone through the roof in CA, people with old gas furnaces are the hardest hit in winter. We saved quite a bit when we upgraded to a heat pump.
- jabart 3y agoNatural gas may be cheap but the cost of the meter and other admin fees cost about as much as the gas.
- FooBarBizBazz 3y agoIt's probably academic, but if natural gas is that cheap, then I wonder about more thermodynamically-efficient uses of it. The classic thing is cogeneration. It's a thermodynamic sin to create a large temperature difference (say, furnace combustion chamber vs. house) without running that heat through a heat engine. In the Nordic countries, in parts of Russia, and on some university campuses in the US, that's done with a "neighborhood power plant" and district heating (steam pipes). Heat engines get less efficient as they get smaller, but possibly a house-scale cogeneration setup could still make sense? But I'm also now curious about something more interesting: In the same way that you can have, say, a propane powered refrigerator, is it also possible to have a natural gas powered heat pump? Suppose it's a cold winter day, and you're burning natural gas in a combustion chamber in an appliance in your basement. There are three temperature reservoirs: The outdoors, the house, and the combustion chamber, at temperatures T1 < T2 < T3, respectively. By harnessing heat flow (Q32) from the combustion chamber into the house, can additional heat (Q12) be pumped from the outdoors into the house? Then the house will get a total flow Q = Q32 + Q12. From Q32, work W = (1 - T2/T3) * Q32 is available. That can then be used to pump Q12 = 1 / (1 - T1/T2) * W = ((1 - T2/T3) / (1 - T1/T2)) * Q32 additional heat. And thus Q = Q32 + Q12 = (1 + (1 - T2/T3) / (1 - T1/T2)) * Q32 = B(T1, T2, T3) * Q32 . Here, B (a function of T1, T2, T3) is the coefficient by which the natural gas' energy is effectively multiplied, for heating purposes.
- FooBarBizBazz 3y agoBelatedly, let's plug in some numbers for the Carnot heat-pump furnace. T1 = -9.4 F = -23 C = 250.15 K (Outdoor temperature in winter on cold day.) T2 = 71.6 F = 22 C = 295.15 K (Indoor room temperature.) T3 = 2236 K (Adiabatic flame temperature of methane at constant volume.) Then we have B(T1, T2, T3) = 6.69. That's very substantial! Of course, this assumes Carnot efficiencies for everything, so it's an upper bound. Also, my assumption of T3 being the adiabatic flame temperature may be too optimistic. Google says > Today's commercial jet engines can reach temperatures as high as 1,700 degrees Celsius (that's 3,092 degrees Fahrenheit) https://engineering.virginia.edu/news/2018/11/generating-current-well-thrust-jet-engines-0#:~:text=Today's%20commercial%20jet%20engines%20can,the%20inside%20of%20the%20chamber https://engineering.virginia.edu/news/2018/11/generating-cur.... so letting T3 = 1,700 C = 1973.15 K, we get the slightly lower B(T1, T2, T3) = 6.58. This is still fantastic. This is also assuming a very cold day, which is when the system will have lower efficiency. If we instead assume T1 = 0 C = 273.15 K, and use the more conservative T3 = 1973.15 K assumption, then we get B(T1, T2, T3) = 12.4. That's huge. So, assuming my math/modeling is right, a hypothetical heat-pump furnace could (using Carnot bounds) use around 1/6th - 1/12th the natural gas as a conventional one, even in a very cold place, if you keep all the other properties of the house (insulation, air exchange) constant.