back to article Electric cars to create new peak hour when they all need a charge

At today's adoption levels, electric vehicles' impact on overall household energy consumption is negligible, but grid planners probably need to look to the future sooner rather than later. Research conducted by Matteo Muratori of the US Department of Energy's National Renewable Energy Laboratory (NREL) finds in the medium term …

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  1. really_adf

    News just in...

    ... from the Department of the Bleeding Obvious.

    Still, at least the issue is quantified to some extent.

    1. Christian Berger Silver badge

      actually no

      It's just ignoring obvious things, like that people won't use the quick charge option for an overnight charge, or that it's trivial for cars to detect an overload condition of the network early on and reduce their charging speed.

      1. LucreLout Silver badge

        Re: actually no

        @Christian Berger

        It's just ignoring obvious things, like that people won't use the quick charge option for an overnight charge

        I agree with most of your post, and certainly that the issue is readily solvable.

        However, the bit above I don't think will be correct, because upon returning home from work people will often need to go back out later in the evening - a night out with friends & family, to go shopping, collect a package fromt he post office etc. They won't always have clear forward visibility of these things and so some people will simply elect for a quick charge as their default charge unless they know they're staying in.

        1. Francis Boyle Silver badge

          Re: actually no

          I can't see this as as serious problem. Even a moderately specced electric car (i.e. anything that's not a Tesla) should be able to do an 45-minute-each-way commute and still have juice left over for a trip to the shops or any of the other in-your-suburb tasks people might want to do on a whim in the evening.

        2. Stu J

          Re: actually no

          As per some other comments, most EVs can cope with a two-way commute plus some nipping about in the evening without a recharge...

          And similarly, per comments about letting the market decide - that's where smart meters come in. My car's configured not to charge between 4pm and 11:59pm, simply because my per-unit rate jumps from 11p to 24p at 4pm, back down to 11p at 7pm, and down to 5p between midnight and 6am. The only way I'm ever going to charge between 4pm and midnight is if I'm desperate... So market forces can, do, and will help spread the "load" (literally and figuratively)

        3. ricegf

          Re: actually no

          Consider a Chevy Bolt, with 238 miles of range, or a Model 3, with 215 miles, or even a 2018 LEAF, with 151 miles (USA EPA ranges).

          The average US commute is 30 miles total. Do we expect drivers (who lack workplace slow charging) to plan over 100 miles of errands in the typical evening?

          On the rare occasion where they will be traveling to a distance city, say for a concert or sporting event, a quick charge replaces those 30 miles of range in under 10 minutes, even at today's leisurely 120 kW charge rate.

          In the next few years, the problem becomes even more moot, with fast charge rates of 350 kW already specified for the Common Charging Standard, and ranges up to 620 miles already announced.

          So, I don't believe this is will be a problem for the vast majority of drivers even in the near future.

          1. MachDiamond Silver badge

            Re: actually no

            "even at today's leisurely 120 kW charge rate.

            In the next few years, the problem becomes even more moot, with fast charge rates of 350 kW already specified for the Common Charging Standard, and ranges up to 620 miles already announced."

            I see a lot of 50kW DC fast chargers. It varies from about 40kW to 100kW for non-Tesla chargers. Tesla chargers vary too as well as what rate the battery controller will allow.

            Past a certain rate, a really big charger isn't that big of a deal. The voltage has to get very high which means all of the components in the charger and the car have to be able to insulate against that high high of a voltage or the current goes way up and components have to handle that. Fast chargers are going to be mostly used for long trips and it's not not a burden for the car to take 20-30 minutes. The last long road trip I did, I was timing my stops. A visit to the loo, fill the tank, eat something and a walkabout to stretch muscles was a minimum of 20 minutes if I didn't have to wait in line to fill up with petrol. Since I only make a longish road trip no more than two or three times a year, I don't mind waiting a little bit more for an EV to charge up. If I were in a big hurry, I'd take the train or <shudder> fly. Even my longer drives aren't more than about 250 miles which is entirely doable in a Model 3 or a Bolt if it isn't super cold out. I can leave the car plugged in at my destination to fill up. Spending less on "fuel" is a big bonus.

            620 miles of range? Doooooood, that's like 9-10 hours of straight driving and a very expensive and heavy battery pack to lug around. I like to be more leisurely about my driving on trips like that and stop here and there to see the sights. If I really needed to do long run in minimum time and was taking the car because I needed to pack a bunch of kit, I'd rent a high MPG diesel with a big fuel tank. Chances are that a trip like that would be for work rather than pleasure.

      2. Cynic_999 Silver badge

        Re: actually no

        How would a car detect an imminent overload of the local transformer? Yes, there'd be some drop in line voltage - but no way to know how much of a voltage drop indicates that an overload situation is occurring. The voltage in a village at the end of a long power run might suffer a 15% or greater voltage drop when everyone switches on their kettles during an advert break on the telly without getting close to overloading the local transformer, while houses close to a transformer might see only a 5% drop by the time the transformer is glowing cherry-red.

        1. teknopaul Bronze badge

          Re: actually no

          The way to detect imminent overload is the way everyone else does it. Half hour billing and let the market decide.

          Businesses pay a different price for leccy every half hour. Producers earn that price.

          Its only if the free market consistently fails or is horribly unfair that regulation is needed.

          That may be the case, but no need to panic.

          A massive fleet of personal mobile energy storage devices that can automatically choose _when_ they purchase, could be, overall, a very good thing for energy markets. In theory when you are working from home your car could even earn money by returning energy to the pool if prices are high enough.

      3. MachDiamond Silver badge

        Re: actually no

        The easiest fix is already in place. Electricity providers mostly offer reduced rates to EV owners if they charge their cars off-peak in the wee hours. Every modern EV I've seen can be set to start charging at a specified time. Some have a feature to default to the programmed time when at home and to start immediately anywhere else.

        A 45 minute commute each way for work is likely only 30 miles or so one way. There should still be plenty of range for an evening's toodle around the shops or cinema or the person bought the wrong car (ie, a Fiat 500e).

        It's best to thing about charging in terms of how many miles of range are replaced for every hour of charging using different power sources. In the US, with half the voltage, it starts at 5mi/hour for 120V, 25mi/hour for 240V and gobs for dc fast charging that will vary with its power output rating. The slowest rate in the UK is about 10mi/hour. That's got the car topped off from the 60 miles of use to commute in 6 hours. If your charging started at 10pm to take advantage of better rates, the car is all done covering the commute by 4am while you are still sawing logs. Nothing is mandated that you have to completely top up the battery every time you plug in to charge so if you wind up driving more one day, it's not a big deal. The more level 2 chargers that wind up in shopping centers and along the high street, the easier it will be to follow your ABC's (Alway Be Charging).

        Robert Llewellyn has a great show on YouTube called "Fully Charged" and there is an episode from way back where he visits the control center for the national grid. When he asked them about EV charging, he was told that they'd love to have more usage in the middle of the night to fill in the "bathtub" of reduced demand. Keep in mind that refining crude into petrol takes 7.46kWh per US gallon of electricity. Just the electricity to make a gallon of petrol can push a Chevy Bolt EV a bit more than 30 miles. The electricity used to refine 8 gallons of petrol will charge a 60kWh from flat to full. The range of the Bolt is advertised as 240 miles (238 really but I'm rounding off). 60kWh @ .12p/kwh is £7.20. How much is 8 gallons (30L) of petrol to push an ICE car that gets 30mpg that same 240 miles?

        I had the same thought about everybody plugging in and charger when they got home but learned that it's really a non-starter. People get home and put the kettle on without a second thought and that is very noticeable on the grid. You won't like the results of making your coffee or tea at 2am to get a better electrical tariff, but it isn't a problem when charging the car.

  2. jake Silver badge

    I've been pointing this out for years.

    The pro-EV set always shouts me down ...

    1. Mark 85 Silver badge

      Re: I've been pointing this out for years.

      Don't forget the greenies who gloat about how they will drop air pollution but then get really irritated when you ask "where's the electricity coming from"? And followed by "how much will all this manufacturing of solar panels, extra power plants and fuel impact the environment.". For some reason they don't have an answer.

      1. Anonymous Coward
        Anonymous Coward

        Re: I've been pointing this out for years.

        Any fool knoa that the extra leccy will come from burning obsolete coal infrastructure!

        Clearly...

      2. Anonymous Coward
        Anonymous Coward

        Re: I've been pointing this out for years.

        There are a number of companies out there that sell 100% Renewably generated Electricity. Go look at Ecotricity.com and see for yourself. (there are other Green Energy Companies)

        It does not all come from Coal (<10% these days) or Gas fired power stations.

        Believe it or not, the UK is one of the leaders in Renewable power generation. The likes of Denmark and Norway do better than us but where our little island is located makes offshore wind very economic.

        If you care to do a bit of research yourself, you could see how much of our electricity generation is coming from which source in real time. also, I'd recommend that you go and look at the posts on FullyCharged where the bosses of Ecotricity and Pod-point talk about their businessed. You might find them enlightening but hey, let the downvoting of an obviously derranged EV/Greenie tree hugger begin.

        1. Nial

          Re: I've been pointing this out for years.

          "There are a number of companies out there that sell 100% Renewably generated Electricity"

          Does their supply drop out at night when there's no wind?

          If not then their supply is not 100% renewable. Obviously.

          1. Keith Oborn

            Re: I've been pointing this out for years.

            As with all other electricity "retailers" the green ones balance supply and demand. In the case of the green ones, their total supply to customers is balanced by an equal supply from renewable generators *over time*. At any given instant they may be either buying non-renewable energy from suppliers to cover a renewable shortfall, or supplying surplus renewable energy back to the grid.

            It is a fallacy that there is no point in "going green" unless you can get 100% of your energy that way. Even 1% helps.

          2. ScottME

            Re: I've been pointing this out for years.

            The wind doesn't stop at night. Nor does hydro-electric power, pumped storage power, and various other forms of renewable energy. Obviously.

            1. Doctor Syntax Silver badge

              Re: I've been pointing this out for years.

              "The wind doesn't stop at night."

              But sometimes it stops for several days.

              1. Anonymous Coward
                Anonymous Coward

                Re: I've been pointing this out for years.

                "But sometimes it stops for several days."

                Depends on diet,

            2. LucreLout Silver badge

              Re: I've been pointing this out for years.

              The wind doesn't stop at night. Nor does hydro-electric power, pumped storage power, and various other forms of renewable energy. Obviously.

              Completely agree, however pumped storage is a rounding error on a rounding error of power provision. Hydro we could, and possibly should, do more with. Biogas from food waste is another reasonable possibility to help with load.

              The further through time we go the better the technology gets, so really avoiding peak oil and CO2 emissions is nothing more than a play for time.

            3. Cynic_999 Silver badge

              Re: I've been pointing this out for years.

              "The wind doesn't stop at night"

              It certainly does on many nights - as well as many days.

            4. John Brown (no body) Silver badge

              Re: I've been pointing this out for years.

              "The wind doesn't stop at night. Nor does hydro-electric power, pumped storage power, and various other forms of renewable energy. Obviously."

              Pumped storage is...erm...storage. Although that does raise an interesting point. Pumped storage is viable because they buy leccy at cheap "dead of night" rates and sell it back it peak demand rates. I wonder how long that will be viable if everyone is charging at "dead of night" rates/times?

              1. MachDiamond Silver badge

                Re: I've been pointing this out for years.

                "Pumped storage is...erm...storage. Although that does raise an interesting point. Pumped storage is viable because they buy leccy at cheap "dead of night" rates and sell it back it peak demand rates. I wonder how long that will be viable if everyone is charging at "dead of night" rates/times?"

                Pumped storage also absorbs over capacity when there is too much wind if possible. Otherwise they have to feather the turbines and "turn them down".

          3. israel_hands

            Re: I've been pointing this out for years.

            Does their supply drop out at night when there's no wind?

            What makes you think there's no wind at night? Where do you think it goes after sunset?

            And as to that meaning a supply is not 100% renewable, you might look into these things called "batteries". This may blow your mind but they allow you to store generated energy and use it later.

            1. Nial

              Re: I've been pointing this out for years.

              > > Does their supply drop out at night when there's no wind?

              > What makes you think there's no wind at night? Where do you think it goes after sunset?

              The point was there's no solar input at night, if there's no wind then renewable input effectively = 0.

              A few slower readers don't seem to have got that.

              1. ricegf

                Re: I've been pointing this out for years.

                Your insults are misdirected. Had the author correctly written "Does their supply drop out at night IF there's no wind?", he would have been understood.

            2. John Brown (no body) Silver badge

              Re: I've been pointing this out for years.

              "What makes you think there's no wind at night? Where do you think it goes after sunset?"

              I think he's referring to those winter periods when the entire UK can go several days with little to no wind. Solar can't pick up the slack at night, biomass is still small potatoes and we have very little hydro.

              1. ricegf

                Re: I've been pointing this out for years.

                It's not necessary to eliminate all fossil fuels, only to reduce fossil fuel use to where plant life can handle the CO2 load again. It's fine to use natural gas as the last line of defense against a significant voltage drop, though we have other options and potential options to explore first.

          4. Anonymous Coward
            Anonymous Coward

            Re: I've been pointing this out for years.

            Umm...night is when there's no SUNLIGHT, not wind!

            Most renewable companies use a variety of sources. Solar, wind, hydro, tidal...it's very rare for them all to drop at exactly the same time.

            Also, haven't you ever heard of batteries? They're used to smooth out the delivery when there are drops in production.

          5. ricegf

            Re: I've been pointing this out for years.

            Not at all obviously. I'm an electrical engineer, and (respectfully) you're confusing power and energy.

            Energy is the potential to do work, such as moving a car. The "power company" sells, and the battery stores, energy measured in kilowatt-hours (kWh).

            Power is the instant motive force that actually stores energy into the battery or accelerates the car, measured in kilowatts (kW).

            The grid isn't the Internet, routing power instantaneously from the wind farm to your house. Power is added to and consumed from the aggregate grid minute by minute in careful balance. So the power feeding my EV battery is "obviously" from a mix of fuels. You're right as rain about that.

            But the energy for which I pay is 100% wind energy. That is, if my EV uses 150 kWh this month, the local wind farm adds 150 kWh to the grid during the month, and I pay them $9. This is what EV owners mean when they say their EV runs on 100% wind energy.

            So, I can power my EV with 100% wind energy without any grid instability at my house at all.

            The UK has actually reached 100% renewable power inputs at slack times, btw. Managing a grid with a large portion of renewable energy requires care, but solving technical challenges is what engineers do. Trust me, it's doable, as is continuing to upgrade grid capacity to continue to track increasing demand. We've been doing it successfully for over a century, and the slow transition from petrol to electricity allows ample time to manage the grid properly.

        2. Adam 52 Silver badge

          Re: I've been pointing this out for years.

          At the moment, just as everyone is about to start their commute (obviously moderation delay means you'll see this lunchtime), the UK is generating 37% from gas and it's the only really short-term scalable option. So short-term the additional load will be taken up by burning gas, ignoring micro-generation. Long-term maybe we'll get more wind or nuclear. Solar isn't really going to help this time of year.

        3. paulf Silver badge
          Thumb Up

          Re: I've been pointing this out for years.

          @AC

          "If you care to do a bit of research yourself, you could see how much of our electricity generation is coming from which source in real time."

          If you want to see the realtime UK electricity demand and what is supplying it this is an excellent resource:

          G.B. National Grid Status. It also has links to historical data as well.

          Right now (10.01 Wed 24 Jan) Wind is supplying 9.94GW of the 39.5GW demand, which is more than nuclear (6.65GW), far more than Coal (1.14GW) but less than CCGT Gas (16.12GW). For context there are strong winds in the South of England at the moment.

          "There are a number of companies out there that sell 100% Renewably generated Electricity. Go look at Ecotricity.com and see for yourself. (there are other Green Energy Companies)"

          OVO Energy is another company that offers 100% renewable tariffs - usually costs about 1.5p/kWh more but YMMV and others are available.

          1. Missing Semicolon Silver badge

            Re: I've been pointing this out for years.

            This, definitely. I watch it all the time (sad that way). Then you get to see how narrow the generation margin is on windless days.

            Far from being reassuring, it's scary.

            For example, on 10-11th of January this year, the OCGT was is use for several hours at peak time.

          2. John Brown (no body) Silver badge

            Re: I've been pointing this out for years.

            "G.B. National Grid Status. It also has links to historical data as well."

            Interestingly, even at 1240am, a time I would expect to be pretty much the bottom of the trough/graph in terms of demand, we are still taking about 10% of the national demand from external interconnects from France, Netherlands etc., although, also interestingly, wind is shown as the largest single contributor at just over 32% and coal at 0%

        4. Missing Semicolon Silver badge
          Thumb Down

          Re: I've been pointing this out for years.

          "100% renewable"

          1) Most "renewable" energy is Biomass. I.e., burning American wood pellets. The process overall (including harvest, processing and transport) generates just as much CO2 as coal.

          2) The remainder comes from unreliable wind.

          So, the 100% figure is a chimera. When the wind isn't blowing, everybody is using electricity from nuclear or combustion.

          This winter, since there was a bit of an outage at a couple of Nuclear plants, they were forced to fire up the Open-Cycle gas turbines when there was approximatey 0.0GW of wind power for several days. Very wasteful, very expensive.

          1. strum Silver badge

            Re: I've been pointing this out for years.

            >Most "renewable" energy is Biomass

            No it isn't.

          2. John Brown (no body) Silver badge

            Re: I've been pointing this out for years.

            "1) Most "renewable" energy is Biomass. I.e., burning American wood pellets. The process overall (including harvest, processing and transport) generates just as much CO2 as coal."

            Biomass may be on the increase, but it's a long, loooong way behind wind power currently. I can't agree more with the stupidly non-green processing and import of wood pellets from the USA though.

            1. ricegf

              Re: I've been pointing this out for years.

              A tree takes carbon from the atmosphere and sequesters it in wood. You burn the wood and release the carbon. Net change in CO2 this century is zero.

              You burn coal, releasing carbon sequestered millions is years ago. Net increase in CO2 this century is significant.

              The percentage of CO2 in the atmosphere had been rising steadily since about 1950, indicating that we've saturated the ability of plant life to handle the supply.

              We don't know for certain the impact of a higher concentration of CO2 in the atmosphere, but "bad" is pretty likely.

              So, investing in not releasing long sequestered CO2 is a very good idea.

              Releasing briefly sequestered CO2 is the better option of the two. Capturing and using fusion power arriving daily from the nearest star is even better.

              Importing wood pellets from the USA is rather suboptimal for the UK, though. :-)

        5. Anonymous Coward
          Anonymous Coward

          Re: I've been pointing this out for years.

          There are a number of companies out there that sell 100% Renewably generated Electricity. Go look at Ecotricity.com and see for yourself. (there are other Green Energy Companies)

          Just how do they do that? Do they have a different set of power lines or do they use the normal grid lines?

          If it is the latter then you are most probably using electricity generated by gas turbines, coal plants and nuclear since, at best in the UK renewable supplies only a maximum of 25% of demand on a good day - much less when the wind isn't blowing.

          1. Anonymous Coward
            Anonymous Coward

            Re: I've been pointing this out for years.

            Ummm...you really don't understand how this works.

            Take the Nestle Fairtrade chocolate scheme. They don't make all their products Fairtrade, just some of them, but they don't have entirely separate production lines (You'd need to for Organic, but that's different).

            So, they say "We buy 1.2 million tons of cocoa each year. We need 200,000 tons to make the Fairtrade products, so we make sure that each year we buy 1 million tons of standard cocoa and 200,000 tons of Fairtrade cocoa". They get mixed up, but the fact you're buying Fairtrade has an effect on their practices, so it has the positive result you want.

            It's not an exact analogy because cocoa can vary in terms of nutritional value, whereas electricity is exactly the same no matter where it comes from. But what you're doing is influencing buying practices. If you are on a 100% renewable scheme and use 1000 kWh, then it guarantees that 1000 kWh of green power is put into the system instead of 1000 kWh of non-green.

            The whole "separate power lines" argument is a fallacy - otherwise every time you switched provider they'd need to lay new cables to your house. All the providers run over the same cables, but it's the sourcing that you're changing.

            1. SImon Hobson Silver badge

              Re: I've been pointing this out for years.

              If you are on a 100% renewable scheme and use 1000 kWh, then it guarantees that 1000 kWh of green power is put into the system instead of 1000 kWh of non-green.

              That's what the greenwash vendors would have you believe - but there is ZERO truth in that. That 1000kWh would be put into the grid regardless - the rules on renewables mean that pretty well all renewables get "first bite of the cheery" in supplying demand.

              So wind always puts in all that the windmills produce - and the energy companies will buy it (even though it's very expensive*) because the rules require them to. Ditto solar, hydro, etc.

              So when you switch on your kettle with your greenwash tariff the result (since we do not have any excess of renewables over demand) is that the taps open ever so slightly on whatever generator is doing the dynamic load balancing at that point in time - typically it will be one of the CCGT stations. So your additional load will result in a matching additional generation from fossil fuel. The actual electrons you get will be from a mix of sources - exactly the same mix as EVERY other consumer in the country.

              So seriously, there is absolutely no such thing as a true green tariff - they are all greenwash, getting you to pay ectra for nothing more than a warm fuzzy feeling.

              * Wind IS very expensive. The operators will happily tell you how "cheap" wind is - but what they don't like to talk about are the direct cost (the 30-something pence/kWh subsidy**) or the indirect costs (the massive costs incurred by the rest of the supply industry in mitigating the effects of a highly variable/intermittence supply that has priority on supply).

        6. LucreLout Silver badge

          Re: I've been pointing this out for years.

          Believe it or not, the UK is one of the leaders in Renewable power generation. The likes of Denmark and Norway do better than us but where our little island is located makes offshore wind very economic.

          Denmark uses Sweden as a giant battery, which is the only reason they do so well in the stats. Their excess power on windy days goes to Sweden, while their nuclear/fossil generated power comes back down the wire on calmer days.

          It's a brilliant idea, but does muddy the water when looking at the stats.

        7. Jimmy2Cows
          WTF?

          Re: here are a number of companies out there...

          There are a number of companies out there that sell 100% Renewably generated Electricity.

          Wait... I'm confused... do you lay your own cable directly to the renewable plant?

          Or does your supply contract come with a Maxwell's Demon electron bouncer to stop those ne'er do well non-renewable electrons entering your premises?

          Pretty sure everyone gets grid power the same way; a mix of whatever power plants supply the grid at a given time.

          1. Francis Boyle Silver badge

            Re: here are a number of companies out there...

            Except electricity is 100% fungible - there are no renewable or non renewable electrons. So if a company owns, say, a solar plant that puts 1GW onto the grid, it can legitimately sell 1GW of renewable electricity to its customers. And capitalism being what it is there are ways to trade the right to sell that electricity so one company doesn't have to be involved at both ends of the supply chain. It's really not a difficult or abstruse concept - it's just the way things work in any society that has evolved beyond bartering.

          2. ricegf

            Re: here are a number of companies out there...

            They sell 100% renewable energy. You're thinking power, which is a different thing. You shouldn't mock others because you lack a basic knowledge of science.

      3. Michael Habel Silver badge

        Re: I've been pointing this out for years.

        And, they'll never will. As such an answer would never fit their naritive.

      4. Anonymous Coward
        Anonymous Coward

        Re: I've been pointing this out for years.

        "where's the electricity coming from"?

        I'm lucky enough to have enough south facing roof space and don't drive all that much, so I *could* install sufficient solar panels to provide more electricity than I need for my average driving needs, if I had an electric car.

        Pity that when I do the maths on the current feed in tariff, it makes no economic sense for me to buy an electric car and solar panels. Hell, I'm not even convinced the solar panels break even on their own given that it would be extremely difficult to shift my usage pattern to use the 50% of electricity generated that the tariff assumes, and I would be paying to use non-green electricity at night. (If you can use the energy from the panels during the day, the panels can make sense...)

        And, no, I'm not buying a battery pack for the house, the energy used in their manufacture, the relatively short life span (10 years, I believe) and the difficulty of recycling them means that for the time being, they definitely fall into the "not green" box. Very useful for people who live off grid though.

        For the time being, I'm sticking with buying nuclear generated electricity from EDF.

        1. MachDiamond Silver badge

          Re: I've been pointing this out for years.

          'And, no, I'm not buying a battery pack for the house, the energy used in their manufacture, the relatively short life span (10 years, I believe) and the difficulty of recycling them means that for the time being, they definitely fall into the "not green" box. Very useful for people who live off grid though.'

          In the next decade, home battery packs will most likely be ex-car battery packs. A 60kWh battery that has dropped to 40kWh sucks in the car, but it's still a lot of power. The projections now are that many packs will spend 10 years in a car and another 10 years in a stationary application before being recycled. The Cobalt used in the Li batteries is what makes them valuable.

          Visit Sunamp.co.uk. They are making thermal batteries to store excess electrical energy from PV panels as heat for hot water and home heating. I don't know what they cost and seeing a video on them gave me an idea to build my own. I am guestimating that it will be around £300-£400 for 7kWh of thermal storage if I can get the parts I want to use from a salvage yard. I'm still playing with the design.

          1. Martin an gof Silver badge

            Re: I've been pointing this out for years.

            Visit Sunamp.co.uk. They are making thermal batteries to store excess electrical energy from PV panels as heat for hot water and home heating.

            These are more commonly known as "thermal stores" and have been around for decades. The basic principle is similar to a standard hot water cylinder, with a couple of additions:

            First, the stored water is not used directly, rather you take the heat out using a heat exchanger. This means that you can store it at a much higher temperature (90 - 95C is possible) therefore storing more energy in the same physical volume.

            Input can be from any number of sources. In the same way that a "solar" cylinder will have two coils, one for the solar collector and one for the boiler, a thermal store could have more and be able to accept heat from perhaps a log burner or heat pump as well. Immersion heaters are easy to fit and can take any surplus from PV.

            Because of the use of heat exchangers, you can take as much or as little heat out as you need, reducing the need for blending valves.

            I've been looking at one from Newark Copper Cylinders for a rebuild project we are trying to start. They will build you a cylinder to your exact specifications and it's not as expensive as you might think.

            M.

      5. strum Silver badge

        Re: I've been pointing this out for years.

        >Don't forget the greenies who gloat about how they will drop air pollution but then get really irritated when you ask "where's the electricity coming from"?

        Don't forget the Dirties, who always ignore the results of surveys that show that EVs are still cleaner - even if every watt is produced by coal (which they won't be).

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