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Under Current Policies, Residential Batteries Increase Emissions In Most Cases (arstechnica.com) 182

schwit1 shares a report: Another year, another reason to take the promises of residential home batteries with a grain of salt. This month, a group of researchers from the University of California San Diego (UCSD) published a paper in Environmental Science and Technology reporting that there are very few cases in which operating a residential home battery reduces overall emissions -- assuming that households are economically rational and trying to minimize costs.

Of course, if the battery is only discharged during periods of peak emissions and only charged when fossil fuel use is low, then a household might reduce emissions. But across 16 representative regions, operating a battery this way ended up being costly. "There may be good reasons to decentralize the grid through ubiquitous installation of small RES [Residential Energy Storage], but cost-effective emissions control is not one of them at the moment," the researchers write.

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Under Current Policies, Residential Batteries Increase Emissions In Most Cases

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  • by Anonymous Coward on Monday December 31, 2018 @03:11AM (#57882734)

    in locality of where batteries replace toxic carcinogenic exhaust fumes.

    Science funded by oil is fascist.

  • by Anonymous Coward

    You have a battery and most days you have a trickling, free energy source just bouncing off the top of your head being wasted. A high % of people who would add the greater expense of batteries would no doubt add solar.

    It's a no brainer yet they don't consider it somehow?

    • by LostMyAccount ( 5587552 ) on Monday December 31, 2018 @04:23AM (#57882884)

      I don't really get solar WITHOUT the batteries.

      The people I know in Minnesota with panels literally don't see much payoff for 10-ish years. The utilities are eventually going to get their way and greatly cut their payback rate for grid buyback.

      Generating and storing energy for your own use is the only thing that makes sense, but right now the economics of it for the average homeowner don't work well.

      • Re: (Score:2, Informative)

        by Anonymous Coward

        Payoff on panels for me is about three years. Admitted lots of sun but no spectacularly good deals on the tariff. Payoff for batteries would be so long they'd be unlikely to ever break even.

        • I'd think you'd have to be getting a good deal on the tariff to get that kind of breakeven, I'm in a small city in Colorado where they've refused to create an incentive structure that'd leave poorer residents funding the upper middle class and the breakeven is closer to 5 yrs. The city isn't particularly backwards (indeed we've got free buses, muni fiber and a commitment to be zero-carbon by 2030) but it's hard to match the incentives that the larger utilities do without disproportionately hurting the poor.

      • Buyback rates will have to drop at some point. How long do you think those utilities can afford to buy power at consumer rates?
        • by Nkwe ( 604125 )

          Buyback rates will have to drop at some point. How long do you think those utilities can afford to buy power at consumer rates?

          Building new power generating plants is very expensive in terms of capital and regulatory expenses. It is also really difficult politically with the "not in my back yard" crowd. By encouraging consumers to generate their own power (using net metering / power buyback), utilities can delay the need to build new power plants. While this is expensive because the utilities in effect pay to act as a big battery (at minimal charge to the consumer), this cost can be less expensive than the cost to build new power p

      • by dfghjk ( 711126 )

        You're using people you know in Minnesota to explain solar economics for the average homeowner? You don't spend much time thinking about this, do you?

      • Solar without batteries uses the grid. Storage is inefficient; so is transmission. If you generate and someone half a mile away consumes, that's more-efficient than battery storage or than transmitting from the power station 15 miles away.

        Because the grid net meters over long time spans, this is more economically-advantageous to the homeowner than using a battery.

        • by Bengie ( 1121981 )
          But much less efficient when it causes a coal power plant trying to spin down. On the whole, blindly dumping power from solar onto the grid is less efficient.
          • Dunno why my solar array should subsidize coal plants. That's a problem for them to solve. If they think batteries are necessary, they can install them at the coal plant.

          • Wouldn't putting it on the grid cause the power load to fall, thus reducing how much power you're consuming? Meanwhile you still need your night time base generation, so running off batteries at night is inefficient.

            Solar on your house is just daytime generation, and would displace load. When using batteries to store solar, actual consumption at peak is higher than just putting the extra power on the grid.

            • by Bengie ( 1121981 )
              Solar reduces the volume of load on coal, but exacerbates the rate at which peak load on coal increases. Just as solar is dropping off, peak usage is ramping up. Coal has issues keeping up. The solution is to throw more fuel at it, which greatly reduces efficiency.
      • Solar without batteries make sense in southern areas where large amounts of solar power mean large amounts of AC. So in that case, it's just lowering peak use costs. In those cases, the correlation of power to usage is very direct.

      • by caseih ( 160668 )

        I've never understood why people think it's legitimate to expect an electrical generation company to buy surplus power from home owners at full retail rates. Why should a home owner be any different than any other generator who sells at wholesale rates? It simply doesn't make any economic sense to force an electrical company to buy power at retail rates when they could get it from other sources at wholesale rates.

        Add to that the problem of peak residential solar not really lining up with peak demand in ma

        • Why should homeowners be forced to sell the energy they generate at below market rates? Would the coal plant operator accept a law forcing them to sell at wholesale?

          • by Bengie ( 1121981 )
            Depends on what you mean by "market rate". Only about 30% of price per kwh is actually the energy. The rest is infrastructure costs, which is relatively fixed. As a source, you don't get the infrastructure value.
            • by MrL0G1C ( 867445 )

              Sure if by 'infrastructure costs' you mean shareholder profit, lobbying, marketing, call centres, taxes etc. Here in the UK the grid part of electricity seems to be 10% of the ticket price per kWh.

      • I don't really get solar WITHOUT the batteries.

        The people I know in Minnesota with panels literally don't see much payoff for 10-ish years. The utilities are eventually going to get their way and greatly cut their payback rate for grid buyback.

        Generating and storing energy for your own use is the only thing that makes sense, but right now the economics of it for the average homeowner don't work well.

        Yeah, I feel the same way. Massachusetts also had a law where you had to sell solar/wind power back to the grid and you couldn't install home batteries (while connected to the grid for power). That's being changed because solar vendors realized that they could make more money by adding the Powerwall to the solar package.

  • I'll remove the PowerWall, and start using the coal burning furnace, and the wood stove and fireplace. /s

    • Wood furnaces, surprisingly, are carbon-neutral: The carbon they release exactly balances the carbon taken in to grow the trees. In principle anyway - there is still the emissions cost of collecting and transportint the fuel. They are terrible for particulate emissions though - lots of smog.

  • This makes sense. (Score:5, Interesting)

    by Ichijo ( 607641 ) on Monday December 31, 2018 @03:44AM (#57882834) Journal

    Even a lithium-ion battery has only 99% charge efficiency, so it makes sense that adding a battery to your photovoltaic (PV) system can increase emissions compared to a PV system with no battery.

    Note the following:

    The researchers found that the only way to reliably decrease emissions using batteries is if utilities incorporate a "Social Cost of Carbon" into their pricing schemes--that is, charging people extra for using electricity during carbon-heavy periods of generation. This helps bring batteries into the emissions-reducing fold. Unfortunately, including a cost for carbon dioxide emissions has proven politically difficult.

    This is why it needs to be a revenue-neutral carbon tax. If the tax is 10 cents per kWh and the average person uses 4,000 kWh per year, then everyone would receive a $400 check every year whether they used any electricity that year or not.

    • by ls671 ( 1122017 )

      If the tax is 10 cents per kWh...

      10 cents per kWh tax? I pay less than 10 cents for 1 kWh from the grid...

      • by xonen ( 774419 )

        Welcome to europe where i pay about 6ct for one kWh, 3 cent per kWh transport/grid costs and a whopping 14 cent per kWh tax.

        Those taxes go straight into politicians' pet projects, not towards investments in renewables.

        My country is not as green as they pretend to be. For example, our politicians are trying to convince the public that driving a 2500kg electric car is `greener` than driving a small and efficient 800kg gasoline car. They promote solar panels but fail to properly insulate old houses. It's all p

        • 2,500kg electric car doesn't use a small, inefficient combustion engine (a larger, slower engine is much more efficient) to generate its power. For driving styles that don't suck down gasoline like crazy, the heavier car stores energy in its moving mass, then transfers about 2/3 of that back to battery during regenerative braking. The greater mass also helps with mildly-uneven ground, allowing the car to travel up hills more efficiently when the hills aren't that tall and the car is already moving at spe

          • by vyvepe ( 809573 )

            the [hevier] car can coast uphill further on its momentum

            You need to review your physics book. How much a car will coast uphill does not depend on its mass. The rest of your claims may have some merit though.

            • The force of gravity acts vertically and the normal force acts perpendicularly on an object on a slope. This creates a resultant force proportional to the mass of the object. A heavier object accelerates down a slope faster.

              When rolling back up the next slope, rolling resistance comes into play. Heavier cars have to run tires at higher pressure due to tire load, so don't have proportionally-higher rolling resistance. Likewise, due to high-performance lubricants, the loss to frictional forces in drive

          • the car can coast uphill further on its momentum, and the car has regenerative braking to further improve on this base efficiency.

            Absent the regenerative braking, the greater mass is always a liability when going up hill, or at any time really. At best, it means that there's more energy being dissipated by the tires and bearings (all the time) as well the suspension (when the road is lumpy.) But when you have regen, the problem of having to spend more energy to maintain speed while climbing a hill is offset by the benefit of gaining energy by maintaining speed when you come down the hill. You still have greater losses in the non-braki

        • For example, our politicians are trying to convince the public that driving a 2500kg electric car is `greener` than driving a small and efficient 800kg gasoline car.

          That's because in many cases the EV actually IS the greener option. There is no such thing as an "efficient" internal combustion engine, at least in https://www.quora.com/How-ener... [slashdot.org]">comparison to electric motors. My Chevy Bolt EV has a fuel economy better than any remotely similar sized vehicle with an ICE you can buy. It's not even close. Furthermore it generates less waste to operate too. I don't have to change ANY fluids aside from wiper fluid for the first 150,000 miles of operation. I've dri

          • If you are basing your Bolt getting "fuel economy better than .. any ICE .. not even close" on the EPA rating of 100-130 eMPG?

            That rating assumes 100% efficient conversion of heat energy into electricity delivered through the power grid to the battery posts in your car.

            Yes, I am aware that some electric power comes from zero-carbon sources and that 60% conversion efficiency is claimed for the best combined-cycle natural gas-fired power plants.

            The claim that you are getting most of your power from gre

    • by AmiMoJo ( 196126 )

      How about instead of a tax the utility company just sends the battery pack a signal to tell it when to activate? Could be done over the internet or some kind of power line comms system or even something separate like ISM band radio (LoRa or Sigfox).

      Have a legal mandate to reduce emissions and reduce costs for consumers, i.e. run it for the benefit of the planet and the owner rather than the power company. Give people a small incentive to adopt it.

      • Yes in principle.

        In practice smart grids are hard because they are massive distributed feedback systems and it's really hard to make one so you know for sure there aren't any resonances. It gets harder still when you have automated trading systems.

        If one runs riot on the stock market, then they just roll back the state of the exchange to earlier in the day (because if you're rich enough you don't take risks to make money). This has happened before. Now imagine it happening on an electrical grid where price

    • Even a lithium-ion battery has only 99% charge efficiency, so it makes sense that adding a battery to your photovoltaic (PV) system can increase emissions compared to a PV system with no battery.

      I think it is not so simple. Not all fossil fuel sources of electricity are equal.

      Here in CA, with a significant amount of residential solar installed, there is concern about the "duck curve" -- solar output tails off around 6pm, while demand increases until about 9pm. This demand must be met by using relatively ine

      • by Ichijo ( 607641 )

        This demand must be met

        Why? Instead of increasing supply, why not reduce demand? That's how eBay works, if you think about it. Does the winner ever complain about being overcharged?

  • by Anonymous Coward on Monday December 31, 2018 @04:20AM (#57882874)

    home batteries are about cutting the COST (i.e. saving money off the home's electric bill)... by storing low off-peak energy (from whatever the fuck the energy generation source is) for use during high-cost peak times.. it has abso-fucking-lutly nothing to do with emissions for most people and most installs (an exception would be an off-the-grid home with solar or solar/wind + battery)

    • It has do to with emissions because it depends on how the base load power is generated.

      In Ontario it would lead to a lowering of emissions because base load is generated by nuclear and hydro. Someone with a battery would be charging the battery with base load electricity and using it during the peak times when gas fired generating plants come online to pick up the extra demand.

      In many places in the US base load is still being met with fossil fuel. If you use your battery during the afternoon peak price when

  • Intuivively, if a battery perfectly stored the energy from the power plant, and perfectly released it, the amount of emissions would be the same as if the battery wasn't there. So it shouldn't be surprising that using batteries doesn't lower the emissions.

    The article supports the intuition by making it apparent that trying to use batteries to arbitrage the emissions from the power plant based on variable emissions efficiency of the power plant isn't likely to cost-effectively work either.

    • Zero-emissions generation facilities (e.g. solar, hydro, wind) are slow to start up and slow down, making them poorly suited for peak/transient loads. Coal, natural gas, and diesel are far more responsive.

      If residential batteries allow for smoothing of the demand side and buffer against unexpected peaking, generation can largely stay with zero-emissions sourcing.

      Thatâ(TM)s the idea, at least.

      • No, that's the idea behind large-scale battery banks managed by the utility company. Coordinating a diverse army of residential batteries to do the same thing is impractical.
        • You co-ordinate it with a price signal. Individual home EMS then acts economically rationally in controlling battery discharge and charge times, and contributes to load following available renewable generation.
          • You sort of coordinate with a price signal, and then you need additional battery banks to deal with the fluctuations that you didn't predict.
      • Zero-emissions generation facilities (e.g. solar, hydro, wind) are slow to start up and slow down, making them poorly suited for peak/transient loads. Coal, natural gas, and diesel are far more responsive.

        I think you have that back to front. Hydro is quick to start up. Coal is typically used for base-load generation is typically slow to start up. Natural gas: it depends on the type of plant (base load or peaker). Wind is quick to start up.

      • Zero-emissions generation facilities (e.g. solar, hydro, wind) are slow to start up and slow down, making them poorly suited for peak/transient loads.

        No idea what you are talking about. Solar panels and wind turbines can be turned on/off extremely quickly provided you have spare capacity. When combined with an appropriately large bank of batteries their response time to load changes is effectively instant and FAR faster than an fossil fuel source.

        You also are ignoring the fact that solar as a general proposition tends to work best precisely when the sun is shining the brightest which is super helpful for use cases like air conditioning that correlate s

    • by AHuxley ( 892839 )
      It shifts the emissions needed to charge the battery pack over a 24h day.
      Solar can help when the sun is out but energy is pulled down the grid when the cost is low to ensure the battery pack is always ready.
    • by Bengie ( 1121981 )
      You make the assumption that the power plant output the same amount of pollution per kwh. This is only true during steady load and the plant at a stead state. If load changes, efficiency drops like a rock and emissions skyrocket. The point of batteries is to stability and smooth out the load, allowing power plants to be more efficient.

      Some years ago, GE announce hybrid natural gas hybrid turbines that had batteries hooked into the system. Normally they have to keep some number of turbines running idle in
  • I don't think I've ever consciously noted this being a bullet point on any pro/con breakdown for PV.

    IMO, batteries aren't meant to decrease emissions. They are a tool towards autarky or optimizing income by putting power into the network when it's most advantageous.

    Or even as a backup if your network isn't very stable some days.

    But reducing emissions really has never been something I think I ever heard as a serious argument.

  • by Jerry Atrick ( 2461566 ) on Monday December 31, 2018 @05:54AM (#57883022)

    Charging batteries from the grid is insane in the UK unless done purely for power security. Most storage systems are hooked up to microgeneration (almost all PV) and the battery is used to avoid selling power cheaply to the grid then buying it back for much higher prices later. Any effect on emissions is a side effect, albeit one that should reduce them.

    • battery is used to avoid selling power cheaply to the grid then buying it back for much higher prices later.

      Here, we have to use net metering. If your power company could meter your power during the day and at night separately, billing on a one-hour cycle, then you'd sell wholesale and buy market, transmission, and taxes. Because it's metered once monthly, you're avoiding that.

      Let's say you overgenerate 10kWh at 8 cent electricity, 11 cent transmission, and 3 cent taxes--21 cents per kWh. That's $2.10 you'd pay to buy it, but the utility pays you only 80 cents. Sounds like a rip-off, right?

      Here's the thin

  • Of course, if the battery is only discharged during periods of peak emissions and only charged when fossil fuel use is low, then a household might reduce emissions. But across 16 representative regions, operating a battery this way ended up being costly.

    I'm pretty sure the time at which the battery is to be charged is set by user preference. It's not the battery that increases emissions, it's the owner of the battery who wants to reduce cost as a priority. It is more important to have a few extra bucks a month to spend on more consumption and pretend to be doing something worthwhile for the environment, than actually do something worthwhile for the environment. However this article tries to blame the battery by hiding the facts under the weasel words "Unde

  • The original paper is behind some paywall. So the cited article is all we have. So the line about, "this research was undertaken by a grant from the Association of Fossil Fuel Purveyors of America" could not be verified. Since it can not be verified I make this allegation casting doubt on the impartiality of the researchers with impunity.

    The paper examines cost savings on one axis and the carbon reduction on another. It showed reduced cost and reduced emissions does not happen. Under certain circumstances

  • If you charge at night when rates are low, you are using baseload power which is often from coal plants. If you discharge during peak use, you are offsetting natural gas turbine plants. Coal produces more CO2 per kwh than natural gas.

    • If you charge at night when rates are low, you are using baseload power which is often from coal plants. If you discharge during peak use, you are offsetting natural gas turbine plants. Coal produces more CO2 per kwh than natural gas.

      Base load plants are generally more efficient than peak load plants. Is the amount of CO2 from an inefficient peak load plant greater than that from a more efficient base-load plant?

      Here in CA, the amount of electricity generated using coal is very small -- I think it is limite

  • by FeelGood314 ( 2516288 ) on Monday December 31, 2018 @11:42AM (#57883976)
    There are 2 big reasons for residential batteries increase emissions. Politics and stupidity, the stupidity I see already in the comments. It will always be economical with people to share generation and storage of electricity. The more people and the further spread out geographically the better. You can form small groups for local management and then larger groups to spread out differences in local demand, weather and generation. Let's call the local groups utilities and the larger group a grid. You can set up solar panes on your roof and buy and sell the electricity to the utility. The utility can then sell or buy from any other utility in the grid. The utility can also have its own local storage to reduce transporting between utilities and also reduce infrastructure locally. Next we need to have the same pricing structure between all players. So when base load nuclear, wind and solar are all producing at their maximums the price can go to zero and when it's a hot cloudy summer afternoon with no wind the price can go to $10/kwh. One bonus of allowing the price to swing like this is that consumers will change their behaviour. Storing electricity is hard, changing behaviour is easy if you have the political will.

    I worked on a very large pilot in Oklahoma. We everyone two pricing options and they paid the lower one at the end of the month. The first was the current system of 12 to 20 cents per kwh. The second was peak prices of $0.78 and the lowest price was free. Average savings per month was $50. Savings for the utility would have been double that. The reason for the huge savings to the utility is it would have reduced the utilities peak demand. Over 10% of a utilities infrastructure is used for only hours a year. Eliminate that peak and you save the utility tens of billions of dollars. The pilot was an amazing success. The regulator of the utility then went and fucked the entire thing up so badly that they pretty much killed the idea for all of North America. Oh, and the politicians all patted themselves on the back for preventing an evil utility from making huge profits. If Oklahoma and Gas and Electric had rolled out the concept for everyone in the state their profits under their new regulated prices would have dropped.
  • Unless you're tying them to an actual means of production (solar, micro-wind, micro-hydro, etc), you're not really doing anything to decrease emissions.
    You're basically playing "hot potato" with grid resources.

  • SMALL home reactors would be the best bet, but the "public utility companies" will never allow that! They would use any an all means $$$$$$ to stop people from disconnecting permanently from the grid.
  • Carbon tax smart.

    Humans dumb.

    To quote a certain replicant: "Then we're stupid and we'll die!"

God doesn't play dice. -- Albert Einstein

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