Exploring the World Unplugged The Secret Life of Energy Storage Net Zero Carbon Houses!
Hi, everyone. We're excited to have you join us on today's virtual tour, a field trip to a net zero carbon house. As noted, this field trip will be recorded and later posted to our website.
Berkeley Lab and SLAC, two of the Department of Energy's 17 National Lab’s have partnered to host a virtual field trip seminar series called Exploring the World Explore the Secret Life of Energy Storage. This series will highlight current and future uses of energy storage and how it decarbonizes our electric grid with major implications to electrifying mobility, accelerating renewable energy deployment on the grid, and enabling energy resilience. First I'd like to introduce my partner in crime, Noel. Over to you. Noel. Thanks, Johanna. Hi, everyone.
I'm Noël Bakhtian I work at the Department of Energy's Lawrence Berkeley National Lab and I'm executive director of the Energy Storage Center, which created this field trip series. I'm so excited to welcome you today as well with our SLAC partners on this journey to an amazing net-zero home that uses energy storage to achieve its goals One of the reasons we founded this series was to help the public and researchers alike get a good look at how energy storage is used in real life and to understand he opportunities and challenges that we need to address together. So with that, back to you, Johanna, and have fun. Everyone.
Thanks, Noël! Each tour showcases real world applications of energy storage, provides a discussion on related science and technology research, and includes an opportunity for you to ask your questions. Together, we're going to learn more about how energy storage plays a pivotal role across the sectors. Now let's kick off today's tour. Today's virtual tour will explore how energy storage can help us reach net carbon zero emissions from our houses. We're going to start by touring a net-carbon zero single family home today ith our field trip tour guide, Dick Swanson. Yes, you're the tour guide! Who is the owner of this house and the founder and past president of SunPower Corporation.
After the tour, we'll hear from two researchers. First, we're going to hear from Gustavo Cezar, a staff engineer at Grid Integration Systems and Mobility, alled GISMo Group at SLAC about the science on how to scale up net zero houses to the community level. Then we're going to hear from Dre Helmns, a postdoctoral researcher in the Building Technologies and Urban Systems Division at Berkeley Lab bout what the future may look like in buildings with new generations of conventional energy storage technologies like thermal energy storage. We’ll conclude today's field trip with a live Q&A. So please drop your questions n the Q&A box throughout the entire tour and presentations.
We’ll get to as many questions as we can in the live Q&A. Also, feel free right now to use the chat feature to introduce yourself our tour group. We'd love to know your name, where you're joining us from, and the first word that comes to your mind when you hear “energy storage for your home.” So Dick, hi! So, Dick Swanson tell us a little bit about this house. Okay. This house came about because we realized some time ago that net zero energy does not mean net zero carbon.
And we wanted to sort of explore he boundaries of that and what it means. We realized that if you're using fossil fuels at night from the grid to power your house, you're not net zero carbon. So obviously we had to bring storage into this picture. And so this house was created as a project to sort of ook at the technical and economic aspects of that.
What I found when first looking into it is that there's a lot of solar powered houses with battery storage off grid, and it's a fairly common thing. What I was kind of amazed at is there's very little data. Like if you see these anecdotal things, like well we built this off grid house and our utility bill went down 20% or 50%. It's almost no use from a technical or economic point of view. So we took a lot of data on this House. And by the way, I wanted to put a pitch in.
We've decided to put the papers, the white papers about it up on the website. Oh Great! My webmaster hasn't yet figured out how to do that. Well, when you do that, let us know where they are and we’ll help you advertise. So there is a lot of data in there about how the house is working. Great! What was the largest hurdle that you had to overcome? Well, he really the biggest hurdles were sort of philosophical in how much energy efficiency we wanted to put into the house, how tight we wanted to make it from a building envelope point of view. You know, we looked at all the way from a passive house standard, essentially would require no energy during the winter, to doing nothing.
And interestingly, with all the modeling we did, we found that the Title 24 requirements in California are pretty like spot on. f you bring your house up to Title 24, as you would if you did a major remodel anyway, you're pretty much at the optimum in terms of building energy consumption. And, you know, you have to realize that when you're trying to limit fossil fuel consumption, the winters, if you have PV on your house, you get plenty of energy in the summer, still want to figure out what to do with all that excess energy, and that's a whole different topic.
But, it's the winter. The winter when you have the least sun and the most heat, that is the problem. So of course we focused a lot on energy efficiency of the heating system and that's where we learned a lot, which you can find in those papers.
Okay. Okay. Yeah. And before we get into the house, what was the total cost of the project? Well, it was, I can tell you, the total cost of the remodel was, I think, $130,000. So it's not cheap to bring a house up to code But, you know, if you're selling the house and a new person comes in and wants to remodel, it makes a lot of sense because the house is way more comfortable.
Just from a human comfort point. The solar and battery system costs about $40,000. Let's take a quick tour through the house before we see the PV array in the back. So can you tell us about what you did to seal up the house so you weren't losing heat? Yeah. So the first thing we did is we did an air changes per hour pressure test on the house. It’s called a blower door test. It measures how leaky the house is as far as infiltration of outside air.
And when they came and did it, the company that did it said it was the leakiest house they’d seen. I don't think many people have taken an old track home built in 1948 and done a blower door test, but it was basically Swiss cheese. Leaking everywhere. Leaking everywhere. he big things were the fireplace, which we ended up just plugging the chimney, dispensing with that. But there were a lot of subtle things that were interesting.
For example, all of the joints between the wall and the floor here were opened and the air was getting into the crawl space below so that when you had the blower door unning, if you walked by a vent in the crawl space outdoors, it was like a hurricane of air coming out there. So to deal with that, we ended up conditioning the crawl space. We basically sealed all the vents. Condition that. That sealed up the house from the bottom. hat we didn't do is the ceiling of the wall to attic joists, because that's a little harder and one of the things we would do if we were to do the house over again. So we took the air changes per hour from about 20 down to six y doing those sealing things, which decrease the energy oad on the house from infiltration by that ratio also.
Can you also explain the heat recovery ventilation? Yeah. So this is one thing that our architects and designers really recommended. And I would, based on the experience, I would recommend it to anybody. It's taking outside fresh air into the house, venting it through all of the vents you see in the ceiling, exhausting it through the crawlspace and then back out through a heat exchanger which recovers the heat from it. nd so the net impact is very little on your energy demand for that.
But the positive feature is that the house has the freshest feeling. People comment on that when they come in and there's no stale air feeling and that sort of thing. That's really important, especially if you're sealing a house. If you're sealing the house really well, n fact it's required by code to reach certain air changes per hour.
But whoever's considering doing this it's a must do. Let's go to the kitchen. Okay. By the way, the heat recovery ventilator eliminates the need for the exhaust fan in the bathroom.
Which is a major source of leakage. Either when it a flapper doesn't work, or when it's on It's just exhausting house air. So instead, there's a minimum amount of air you keep circulating in the bathroom that you never have to have it.
Same with the kitchen, like the exhaust fan with the stove. So when you're burning something. Right. Right.
So there's a lot of benefits. This is the kitchen where we put in new energy efficient appliances and that sort of thing. Like an induction stove. I know we probably don't have time to look at the laundry room, but we also put, I chose the washer / dryer by just the highest ENERGYSTAR rating. And what's interesting is this company from Turkey called Blomberg and it's a heat pump dryer and a very efficient washer.
And I can tell you that the client thinks they’re just fabulous I mean, it creates a completely different feeling of dry clothes in a or conventional right and uses way less energy. Way less. Yeah. Yeah. So when we get outside the PV array.
So we elected to put the PV on in a shade structure like this, hich you can see overhead and used bi-facial modules, so that we would get some benefit from the light that is reflected off the ground and gets on the back of the modules. I also like the transparent modules, you know they have a very pleasing look in my view, rather than the conventional sheet, white back sheet. This creates a real nice space.
We have a table of chairs there for people and one of the reasons that we ended up doing this, which I'm glad we did, is that the array’s fairly large for a house this size. It has half the floor plan of the house, and so it's fairly heavy And the structural engineer said we’d probably have to reinforce the attic to put this much array on the roof. So we just put it here and it's worked out great.
Yeah, it's beautiful. Definitely. Can you tell us initially about your plans of wanting to be off grid? Well, yeah. I mean, obviously, if you're off grid, you're not using fossil fuels by definition from the utility Right? So that was like an endpoint. And at the end of the day decided not to leave the breaker on. . One reason was that I was interested in the output of the array to compare with modeling.
And if you go off grid, as soon as the batteries are full, which happens, by the way, at 10:00 this morning, the array shuts own and you don't really know how much it produced. So I wanted to leave that on, we can go off grid by just starting the breaker. There is some confusion, which I'm not completely clear on whether we could have eliminated the interconnected installment code in it. Perhaps you people know that answer. here's a lot of discussion on the web about this.
So anyway, we ended up being disconnected and we. How much do you sell back? Well we used here about 3,700kWh a year and we sell back about 7,000. So you can see the impact of trying to design to get through the winter. The array is producing, annually, you know twice as much as we use, right? And we're selling it and we're getting you know what I think is a reasonable price for it. Right now we get about five or six hundred dollars a year to get that with the energy we sell.
And so that's nice. One more question about the PV array. I noticed that it’s flat. Can you talk about why you decided to make it flat rather than angled? Well, for one thing, it was just appearance. To make it a nice shade structure.
Secondly, modules have gotten so cheap that there's really no need, you know, n the early days of PV we used to argue whether it should be latitude plus five degrees or latitude plus eight degrees, you know, to optimize. But PV modules are as cheap as roofs now. And so you just put them on there. Secondly, it's interesting in that in the winter, which is the problem, as I mentioned, the real problem is cloudy days. his array will produce average through January, about the same amount as the house uses.
So average is okay. Problem is, three or four days of cloudy days in a row, the batteries run down. . So it's on those days, cloudy days, that you're really having to get the best you can.
And in fact, the best you get in on a cloudy day is 40 days experience. So playing straight up is not it's not as detrimental as we used to think. Well, let's go see your storage. So I think what we see, we got two Tesla Powerwalls. How did you end up going with Tesla's Powerwalls instead of another option? Well, when we built this house, designed it in 2017. They were by far the only option.
And they had a lot of experience. And I would still go with, by the way, it's been, they’ve been fantastic, but it's all rather standard now. I mean, this is nothing exotic. Our installers
offer 50% tax rate on new systems using Tesla Powerwall. You're sticking with Tesla Powerwalls because the reliability has been so good, but there's lots of other choices available now. So there's nothing terribly unusual about having 26 kilowatt hours of storage in a house nowadays, but at the time we did it, it was a little bit unusual. And you decided to go with two Powerwalls. Did you explore other options?
Right. Right So we used the DOE model, the BEopt, which is an NREL supported program that looks at building and energy consumption and does an annual model on it, but it doesn't conclude storage very well. o we coupled that with home, the microgrid modeling program and basically just, you know, we varied everything array size, battery size, you know, and explored that whole space about where we would require minimal amount of support from the utility. And that's what we came up with the even kilowatt array and 26kWh of batteries. And how many kWh, oh you said 26, right.
Were there any safety concerns you had to consider when you were putting your Powerwalls here versus inside the garage or…? Well, not at the time. You know, I didn't really worry about it, ut then it was after that, you know, there was a lot of concern bout lithium ion fires and that sort of thing. And in retrospect, ou know, there's new requirements on battery mounting. You have to, if they’re interior, there's a lot more requirements and coding and that sort of thing. If there near a window,. there's a lot of requirements, but at the end of the day, it's proved to be very safe.
I keep an eye on Tesla Powerwall fires and that sort of thing and it's not to worry. I did have people tell me I was a c omplete idiot for putting a lithium ion battery anywhere near the house. You got a garage? Yeah, yeah, yeah. Anyway, this is a stucco wall. So how does the Powerwall integrate with the PV system? And they all integrate with the grid.
Can you explain a little more about that? Well, there are several options you can do with the Tesla system. We use what's called self consumption mode. Okay.
n the self consumption mode it sort of mimics off grid s much as possible and it will run it off grid until the utility is down of course. But in self consumption mode, the PV array first is used to power the ouse, if there's any excess energy which is a lot right now. ight now it's going into the batteries, and if the batteries are full, it's sending that excess then back to the utility.
And that's what we're getting the $500 to $600 per year rebate. If the grid goes down, of course, it flips into a backup backup mode. How long can you go with sort of in blackout mode? Well, it differs between summer and winter because in the winter we have a lot more heating load. It's on the order of two days of the autonomos, what they call the autonomous operation.
But we can get through a cloudy period much longer than that ecause the two days assumes there's no generation. e get some even on the cloudiest days and we can go for five days typically. nd then when it gets really bad, that's when we’ve had to draw n the order of 150 kilowatt hours a year off of the grid. If we had been truly off grid, we would have just been down. And in the summer,can it last weeks? Well, in the summers you use about half as much energy in the house as you do in the winter. And so we could go for 4 or 5 days.
Do the batteries lose charge If they're just sitting around? Is that noticeable at all? I have no idea because it all has to do with the PV array. Okay. So they never just go down, They're always working. they’re always working. Like, I can guarantee I have a with this my app, but there are 100% right. Okay so looking a little bit sort of into the future and your future plans, what do you want to tackle next? What big energy or sort of global issue do you want to tackle next? Well, that's an interesting question, when we realized that we were not net zero carbon, we tackled this.
nd then it suddenly occurred to me that we're not off grid. We're actually using a sewer systems, we're using water piping, water purification systems. So right now, we're looking into water and trying to minimize the use of eep water and extracting water rom the air, it's called atmospheric water harvesting. Water is very important in California.
It is, and the goal there, just like it wasn't PV originally when we were 200 times oo expensive at the beginning of the PV era, we met where it was cost effective. In fact, by some measures, the cheapest form of energy, atmospherically harvested water is more expensive than what you can get out of a tab. But not a lot. Oh, okay.
And interestingly, the difference between wholesale electric power and electric power that the consumer sees is like a factor of four or five, difference. And that difference is largely transmission and distribution cost. And it's the same, and I was surprised, the same is true in water that the water utility pays a certain amount for the water it gets and charges you about five times as much here at the house and that's all distribution cost. So there's hope. So, yes. Okay, we'll talk in ten years. We know we didn't get a a chance to go in the garage, but you don't have an EV charger in the garage, right? Right.
How would have your plans with the PV and the number of Tesla walls you have changed if you had an EV charger? Well, one of the things we've learned is that having vehicle to grid capability is super. A no brainer. And everybody should be pressing for that, both technically and policy wise. If we had had an EV, we certainly could have gotten away with roughly half as much PV and one of these and it would have been fine. think one of the things with with the EVs is that you really want to charge them during the day when we have solar on the grid and often solar is having to be curtailed o it makes total sense to be plugging EVs in. But at night when most people were home, yeah, it doesn't make sense. So I think one of the enabling things will be to facilitate charging at work, for example, people that work during the day and then they can bring that power home.
Right, so on a cloudy day you could use your car instead. You know, for example, my Tesla's got a 100 kilowatt hours. I mean, this is only 26. So yeah. So it would be like trivial for my Tesla to run this. So one last question As we're looking to scale from one single house to the community level, in your opinion, is it better to retrofit like you've done here r at the community level to really be thinking about new housing? Well, I think it's both. We have so many houses we have to look at retrofit.
nd I'm absolutely certain that if we get an industry going of deep energy retrofits, the cost will come down. I mentioned the cost, but a lot of that cost was just architecture and engineering cost. So much of that cost, if we were to do it again to be a lot less and if everybody got involved in it, it would be a way lot less.
And I think people would figure out what's the cost-effective thing to do The PV and battery parts kind of you know, we know how to do it. we know how to. Thank you so much. This was a great tour. And you know audience, f you have more questions that we didn’t get to please put them in the box and we'll learn a lot more during the Q&A.
All right. So excited to hear the experts talk too Yes. Okay. So now we're going to hear from the researchers. irst, let's join Gustavo Cezar, a staff engineer in the Grid Integration Systems and Mobility (GISMo) Group at SLAC National Accelerator Laboratory. He's going to tell us more about plans for how to scale from a single zero carbon house to the community level. All right.
So I guess I'm on and hopefully everyone can see my slides. So I'll start off y saying Johanna already introduced, So I work at GISMo Reintegration Systems in Mobility, which is a group within the SLAC National Accelerator Laboratory. nd so to start off the talk, I'll just give a brief introduction about what we do and why we're working on this space. And then I'll talk a little bit more about the challenges n scaling down that net carbon zero concept and also a couple projects that we have that we're actually deploying these type f technologies and the algorithms that we developed to, in order to be able to achieve such a goals, which includes net carbon zero, but also support grid operations.
And so, basically this is the old grid and how it operated back in the day. So have a big bulk generator and power is flowing from generation to transmission line and that's the substation distribution and then all the way to the customer. But more and more we've seen the deployment of electric vehicles and the tour that Johanna and Dick provided to you guys showed a lot of the technologies that are being deployed at the customer level. And so not only that we're seeing a lot of renewable generation being added to the transmission also the distribution. So the new grid looks like this picture here.
So we have multiple distributed energy resource or DERs behind the meter, in front of the meter, and most of them are cloud connected. So there are multiple ways of communicating with them, controlling the information, being able to do better forecasts on the generation and also the load side of things. One other thing that is actually happening is the customer behavior. So customers are changing their behavior and how they're working and operating with respect to the grid. And so this also needs to be accounted into the whole framework of net carbon zero.
And so because of that, that's how our group is structured. There are three main pillars. One is focused on the grid modeling part of it. The middle one is DER so how can I integrate DERs on the grid as a whole? And then the third piece is the mobility, so primarily focused on transportation and electric vehicles. And so ithin all these, within the three pillars, we have two other ones that came after the realization of everything is all connected, so there has to be cyber security because if someone is able to attack, for example, Tesla server, they can actually discharge all the batteries at the same time or charge all the batteries at the same time.
And from an operations perspective, you can start creating a lot of problems in the infrastructure itself. nd so cybersecurity is a key component, something that we are heavily working on. And then when you're collecting a lot of data, ou need to be able to start the data, you need to be able to manipulate the data and how to operate and run all your systems.
o algorithms, forecasting, and optimization and so on without the computing infrastructure that you need. And so our group has three main pillars and then the two supporting pillars that we follow. So now speaking a little bit more about the net homes and that scale. So there are multiple drivers t owards the net zero concept.
And based on our experience, I'll be focused on four. So home electrification, government subsidies, emission goals, and advancing communication and cloud computing. And so however these drivers bring multiple challenges, they are intrinsically coupled and can e worked on in isolation in order to reach the net zero. So we have to account for all of them so that we can make this work. And so the home electrification, what are the main challenges? o grid infrastructure overload. One of the key concepts of the net
ero is transitioning all the gas generation in your homes to electrical. And so there's a lot of work being shown so of quality utilities Kevala, which was consulting company that did work for California Commission showing the impacts on the infrastructure. if we start transitioning all the electric appliances, all the gas appliances to electric ones. And so there's heavily infrastructure overload nd it causes transformer explosions and also overload of circuits.
So you can see here on the screen all the hotspots on a circuit breaker showing the overload of that system. The other ones are government subsidy. o there are a lot of subsidies that people cannot leverage from the government, but it's too expensive for the average person. And one of the key things here is the installation challenges. o from our experience in doing deployments in the field, if we try to attack to address the equity issue, we go to the … communities or even median income communities. But one of the things that we found is actually in order to install hose devices, we need to go and get permits and also inspection from the building office.
And so if your system, if your home electrical system is not properly wel wired and have all the permits, you face a l ot of barriers and so on this picture here we show a common mistake that we see in multiple residential panels nd it doesn't matter if you're a low income, median income, high income, you see this all over the place. So double tapping breakers. So in order to install a battery system, for example, you need to do an inspection, once the inspector comes and says, “okay, you have to fix this before I can issue the inspection.”
So there's a lot of challenges on the installation part of it. Emission goals. There is no clear definition of what net-zero means and how to use emission values. And one of the key problems here is being able to cherry pick whatever works best for your case.
And so there's a great article that was issued at Stanford GSB, which is called “Are Big Companies’ Net-Zero Pledges a Well-intentioned Shell Game.” And so this is a very interesting article. nd here in this graph I'm showing on the left hand side the average emissions profile from the gri his is California data and then the marginal emissions profile. So which one you would use depending on whether I'm charging my vehicle in the morning or charging in the evening.
So if I’m charging in the middle of the day, for example, I can look at the average emissions and say, Okay, I'm good. Net carbon zero. The grid is very clean. But then if I, if I actually ut then if I actually look at the marginal emissions, \I might actually be on the opposite. o we need to have a clear definition and standards on how to use each of those metrics.
And so the other piece, advancements in cloud computing and so on, communications, but what are the key challenges in actually implementing that in practice. o we see a lot of challenge with latency of communication performance accuracy, reliability, and integration. So here's just one example So the orange curve is showing the signal that we sent to one of our units that we have in the lab and the blue one is actually showing the response. So we can see there is a lot of delay on the response. We are not tracking the signal very well. And so there are multiple challenges on the system, on the operation of this system in real world conditions.
So that's another challenge. But all of this is very important for us to address. And so one of the reasons why we built this lab, that I'm here today at SLAC, so I have a picture of the lab, but also I'm here and I can show. So we have a sun battery system here. We also have the same system that Dick has in his homes from Tesla Powerwall. We have two solar systems with different technologies.
One, uses the string array, the other one uses micro inverters. And again, I can dive into the technical details on the Q&A about each of these. We also have multiple outlets and we have two charging stations outside of the lab. And this is just like a single line diagram of how this system, how the electrical system is broken down here at the lab So two experimental homes, different hardware, similar huggers, but from different manufacturers. So that we are looking into being hydrogen agnostic.
Right. So I don't care if it does appear always to have a sun any five senses, whatever. If there's a way for us to integrate and develop algorithms to help you achieve the net carbon zero or reduce your cost of electricity and so on, that's the focus of our research here. We also a have Sister lab that we follow at Stanford and so we have similar set up.
But at Stanford, one thing that we have is a grid emulator. So this big box here, we can actually play with the information that we get from the grid. So instead of being like split phase 122, 40 volt, 60 hertz frequency, I can actually add some sags and swells to the voltage and current, voltage and frequency and see how the system would respond to those sags and swells.
And so we also built a user interface and a platform that we can collect data. We can also test algorithms and see in real time what's happened. So is the SGMP platform that we have running in our lab here at SLAC.
And so we can see that we're monitoring how much solar we are generating, how much load we're consuming, battery when it's charging and discharging the EV load. So the EV is purple the blue curve here is how much you're consuming from the grid and the bars here are solar, the blue ones and the yellow ones are battery charged. And so we're able to monitor this in real time.
And this is actually what's happening today here at the lab. We're running a lot of tests with the batteries right now. So we can see there are times that we're charging the batteries, while we have EV load and also we have other loads here. And the other piece that we have in the lab is a real time monitoring system. So this one, we can get second level information. The previous one, that's SGMP we have around like 5 second data and we're displaying at every 5 minutes.
So this one here, we can literally see all the breakers that we're monitoring n each of the sub panels that we have, and we can see all the real time information. And so I will talk now really briefly about two projects. I know I'm running out of time. And so the first big project that we have is called Powernet and so the main focus here is coordinating the DERs at scale from the cloud.
And so as I mentioned, we broke down this project into the cloud coordinator and the home hub. So the cloud coordinator does this synchronization across the meter and the home hub is our local intelligence and so effective coordination needs to deal with four main points. So power grid constraints, I can't overload a transformer, otherwise it's going to accelerate aging and blow up, cloud communication network constraints, user preferences, and also scalability of deployment. As part of this project, we ran a bunch of tests in the two labs that I mentioned. So this one here is just showing the ability of our algorithm to track a signal and how to operate, turn on and off the loads so that we are able to track the signal. And then we expanded that from ten homes that we've built in the lab to close to 14,000 homes in the simulation, so that we can show the capability of the system at scale.
And here is some of the algorithms that we played in the lab here at SLAC. And so the whole point was, so the top one is what the optimization does. o the green curve is the battery, the red one, the solar, and the blue one is the load that we are at, primarily EVs, and the middle graph is just the net load when we're optimizing, and the bottom one is the net load without the optimization. nd so the problem was trying to do a cost minimization. We had a penalty for exporting power back to the grid and a few constraints on the battery. And so we achieved a savings of around 5%, primarily because of the rate structure that we had set up here, which is a standard time of use rate.
And so the key points is what is better? Hovering around zero but with small amplitude like in the middle graph or being zero most of the time, but having large spikes like in the bottom graph. And also from an emissions perspective, if I use average emissions, which one is better? If I use marginal emissions? So these are all things that we're trying to account for in our strategies to control the load. We also did deployment in the homes to install batteries and launch the system in 14 homes.
In Fremont on the right, we're showing one of the homes that we have and then the bottom ones are another home. So different usage, different appliances and different behavior from people. So different usage, different appliances, and different behavior from people. So there is like different clusters of people that you can put them together and say, okay, this person belongs to this cluster more or less based on their behavior and so on. So the behavior part is also very important. We also did a deployment in the farm, and so we field tested our system, by managing batteries, solar, and the load controllers, which primarily operates the fans.
And so a couple of the results here. We reduced electricity cost from the dairy farm around 90%. We reduce emissions near net-zero carbon free for the month of July. And we also provided a user interface because at the end of day you can see electricity, you just see \the cost at the end of the day.
So from a farmers standpoint and the operational part of it, it's very relevant to know what fans are working or not because that impacts their new production at the end of the day. And the last product is TESS, called Transactive Energy Service Systems. And primarily this project, the whole point is implementing a true transactive system. And so this has not been demonstrated in the field, primarily the ramping price and the storage price.
And this is a project funded by the DOE under the Connected Communities. We are working with New Hampshire and Maine and the goal is having between 100 and 250 homes with smart devices, battery and storage systems, EVs, and doing all the coordination, using the transactive system. So I'll stop here. I think I'm done with time and happy to answer any questions later on.
Thank you. Thank you, Gustavo. Yeah, we look forward to having an opportunity to ask all those questions we have. So please put them in the Q&A box. Next for this
coming up portion of the event, let's join Dre Helms. They are a postdoctoral researcher in the Building Technologies and Urban Systems Division at Berkeley Lab, a bit of a mouthful, for a presentation about what the future may look like in buildings with a new generation of conventional energy storage technologies like thermal energy storage. Take it away. Should unmute myself for this. Awesome. Thank you so much Joanna. Let's get in presenter mode. Okay.
Can you flip the screen. Yes, my, there we go. How's that? That looks great. Thanks. Okay, perfect. So I'll jump right in. One of the key things that I think we need to focus on is energy used for heating and cooling.
So 60% of the energy that we use in residential buildings is in the form of heating and cooling. So you can think about hot water, air conditioning, heating, refrigeration and these bar graphs. And hopefully you can see my cursor, these show electricity use in residential buildings and also in commercial buildings. And you can see that heating and cooling already use a substantial portion of building electricity. So if we consider switching the remainder of our energy source, kind of shown over here in this pie chart in the bottom right, from natural gas to electricity, we're going to have even more electricity use for these heating and cooling appliances. So you can think hot water heater, dryer, cooking, basically the electric demand is going to grow.
And so since energy for heating and cooling And so, since energy for heating and cooling already causes this peak electric demand, and it's going to do, it will do so even more, as heating is decarbonized, we actually have a really big problem for the grid. So the grid is not prepared for heating to be electrified. And so one way that we can address this is to align renewable energy supply such as solar, which is kind of shown here in this figure as this yellow line, we can align this renewable energy supply with a more flexible demand. So the appliances that are actually using energy, let's try and match supply and demand. So how do we do that? We can turn to energy storage. You're probably familiar with several types of devices for energy storage.
I like to group these into four broad categories. So electrochemical, think batteries like the Tesla, Powerwall or even the electric vehicle itself. Thermal through a material that's good at staying hot or cold. Chemical energy storage, including cleaner fuels like hydrogen. And mechanical energy storage with pumped hydro and compressed air as popular examples. So Berkeley Lab, we have this amazing facility where we can test these different storage technologies.
So I'm going to promote FLEXLAB® a little bit as a place where I've done research. FLEXLAB®, which is shown here as these blue buildings, is this advanced building technologies and grid integration facility where you can basically test all sorts of building technologies. So FLEXLAB® has been in operation for seven years. They've already conducted 60 plus R&D projects and the focus of FLEXLAB® is to test under real world operating conditions. And so you can kind of see in this photo we have a number of testbeds, we have the rotating test bed and three other test beds here which have identical test cells that are side by side.
And so users can come and do these comparative tests where in one test cell you might test a particular, maybe standard HVAC heating, ventilation and air conditioning system. And in the other test cell, you might test a new one to kind of evaluate the performance and see if you can do better by changing things up. So that's some of the research that we do at the lab, which I think is really cool. And it's not just us as lab researchers who can use these facilities. External researchers can actually also get involved and do R&D projects here. So if you're interested in using a facility that has thousands of sensors o do decarbonization studies, this is a great place to come and do it.
So one of the technologies that I've tested in FLEXLAB® is thermal energy storage using phase change materials or PCMs. So for folks in the audience who might not be familiar with PCM, ice is a great example. So you probably already consider ice to be a great material or thermal energy storage. Let's say you're going to a park, you want to keep your food and your drinks cold, you stick ice in your cooler and you can keep, keep that stuff cold for a long time. o the cool thing about other phase change materials besides ice, is that they offer this benefit of phase transitioning.
So melting and freezing at temperatures that are ideal for building applications like space cooling, space heating, and water heating. So this bottom figure is some experimental data from the lab, from this test setup, actually, which is showing how warm water can enter this thermal energy storage device. And it leaves at this much cooler temperature. And basically it's rejecting heat into this phase change material, which is melting at 11 degrees Celsius. So we're getting cold water and we can use that cold water to cool our building.
Another great thing about phase change material is that it's energy dense, so you can store a lot of energy in a very small volume. nd this is really important when we're retrofitting existing buildings, which we're going to have to do a lot of as we decarbonize the grid. o we're calling that the goal is to enhance demand flexibility.
My team designed these integrated systems that are capable of shifting heating and cooling loads to times when electricity is clean and cheap. So let's consider heating mode for this home in Massachusetts. I have a heat pump here at the left hand side of the screen, which pulls thermal energy from the outside air and puts it into water. And then hot water from this heat pump can flow into these thermal energy storage devices and charge up the phase change material by melting it. And then later when a room needs to be heated, so it's a cold winter day, occupants want to stay warm.
That warm water can come from the thermal storage and directly serve this fan coil unit, which is just an air to water heat exchanger. So here's the type of integrated systems that I've been working on in my research. And in addition to that residential system, I've also been working on a commercial systems. And so what you're seeing here is a compact prototype hat we plan to install on an office building, actually at FLEXLAB®. So hopefully the FLEXLAB® staff will be comfortable. And this system also includes a heat pump shown over here phase change material, thermal energy storage, and a fan coil unit.
So very similar to the residential system I just showed. The main difference here is that these technologies are not also serving water heating loads because there's no sinks o any sort of hot water needed within the actual office space. So it's been super fun to build this prototype that we designed. And I'm going to show you some pictures and I'm going to do a little tour. Hopefully it's not too choppy, but basically in these pictures, starting at the left and you're going o see some of these devices in a second, you can see a heat pump and the controls or this integrated system in this box. In the center pane, we have two phase change material thermal storage batteries with inlet and outlet piping so that they can connect to the heat pump and connect to the fan cool units.
So I'm going to try to do this screen switch. Johanna, if you want to support me here. Yeah, no problem. So while they're getting started with switching to a mobile device, I think everyone can take a moment and add more Q&As to the Q&A box and hopefully we'll be able to see this in real life.
Excellent. We can see you. Yep. And you can hear me, too, right? We can hear you. Yeah. Awesome. So I'm just going to give a quick tour, hopefully not too choppy of those devices that I just talked about in this integrated system.
So here we've got the air to water heat pump where air is kind of being drawn in through these fans and thermal energy is being added to, or rejected from that air, or to that air. Sorry. And that's being transferred to water. And water is what's coming out of the back of the heat pump here. So this heat pump interacts with this thermal energy storage cart. And I’ll kind of back out so you can see it.
And so we have these two thermal batteries. The one in the front is the cold thermal storage and the one on the back is the hot thermal storage. So these are for space cooling and space heating. And then we're bringing water into and out of those thermal batteries through these pipes. And then this cart is interacting with the heat pump and with the fan coil unit through this balance of plant. o what you can see over here is some valves, a flow meter, and a pump.
And that's how basically we can charge up the storage using the heat pump and then discharge the storage to serve this fan coil unit. So up top, we've got a fan which is delivering energy through cool or hot air to a space. nd then this fan coil unit here is a water to air heat exchanger.
So water is coming in and out. That water is hot or cold based on what we need. And yeah, this is the entire integrated system.
So I'll stop my tour here and I'm excited for Q&A. Thank you so much, Dre. Now let's have all the panelists come back on screen and we can start responding to the questions in the Q&A that we have. And we've got lots of questions already. Hello. Gustavo Dre is back on, and hopefully we'll get Dick on.
So while we wait for Dick to come back on and get his video working, I have a question from Justin Cook. Justin's asking “EV drivers learn to drive differently simply because of better feedback from energy consumption to the users. What are the changes users do once a home is net zero?” So I don't know if Dre or Gustavo want to talk about that. Yeah, I can chime in here. So the behavior is actually one of the hardest problems that we have to solve.
And so in one of my slides, I show how you coordinate the battery plus solar to charge an EV and additional loads. And as you can see, the battery is not the best device to charge an EV because again, most of these batteries that we connect in the home, so the stationary storage, they are around roughly seven and a half to eight kilowatts. The Energizer can scale that up, but the power rating is somewhat limited based on the inverter that you have in your system. nd so when EVs start charging if you have a level two charger, for example, it’s around like 7.2 kilowatts, right? So in the batteries that we have in our lab, it depletes in around like an hour and a half, 2 hours. nd so if the homeowner is expecting to be net carbon zero and charge the EVs at home, it's not an easy way to do and that person needs to really understand the dynamics at play around.
So I might not have my EV fully charged if I'm charging overnight because I have the battery and if I try to be net carbon zero, my battery will be depleted and I might have maybe half of or 70 to 80% of my EV charge. And so there has to be an understanding from the homeowners perspective as well that the battery is not infinite. So we have a limited capacity from the standpoint also from the power standpoint.
And so there has to be some education over there as well. So I don't know if that addressed the question, but the behavior part is one of the most challenging ones, I would say. Yeah, Dre did you have anything else to add? Yeah. So I would just say as someone who currently lives in an apartment building under time of use electricity pricing, I know when PG&E peaks are happening, I turn off my devices. So I feel like you can already train people just through cost.
And as we shift to more electrified technologies that that will continue to work. Excellent Dick, I have a question for you. If someone wants to do what you did to their house, what's their first steps? And hopefully it's something simple like look up these three companies online or is there a checklist online that they can, you know, the how to and what's the first thing to do? You need to unmute.
Okay. Sorry. Yeah. Okay. Sorry.
I think you. What you ought to do is employ an architect that's experienced in passing houses and that sort of thing. The company we used was called FGNY in Palo Alto and they were very knowledgeable and really helped us through the whole thing. In addition, the installers, both the battery and the PV installers can help you a lot. So I think between he PV and battery Installer and an architect that's going to help you with the deep energy retrofit, you're good to go.
Awsome. Thank you. Dre, I have another question for you. What is the energy offset equivalent saved from the PCMTES and the FCU residential unit? And this is from Patrice Warner. Okay.
Energy equivalent offset. So I'm not quite sure, I'm not quite sure how to answer that question because basically what's happening is that we're shifting, we're shifting hat energy use to a different time of day. And the benefits of shifting that energy use are associated with the energy supply at that time. So let's say you're able to shift the energy use to a time when it's all wind or all solar locally or on the grid, then your benefit is all of the greenhouse gas emissions that would have come from using those devices at sort of the time, the original time that they would have been used.
If that, I hope that answers the question. But I'm happy to continue to follow up in chat or over email. Great, thank you. Dick, I have another question for you.
For batteries in the zero carbon, are there any programs that you found rom the utilities that encourage batteries discharging power back to the grid during peak grid electricity hours, for example, in the evenings? Not that I found, but I read about a lot of interest in it. So it certainly, it’s certainly something that's coming and I think utilities and regulators really have to scratch their heads and get that whole area squared away. It just makes total sense.
know that, you know, a lot of my work was funded by utilities. And when we built this house they put in, since we put solar in, they gave us an upgrade on the service panel. So went to a 200 AMP service panel, free.
So the utility really was benefiting. I mean was encouraging us to do it. I don't think they realized that we were going to net sell them energy and also get paid $500 a year rather than sell it rather than buying any energy from them. But sure, there's that, there's the Self-Generation incentive program and all these things. And again, all of the installers are very aware of all of these programs and can help people through it.
And Johanna, if I can chime in here real quick, just to mention, so from a customer perspective, so if I'm a homeowner or a Dicks example, for example, there is no at least that I'm aware, there's no program like that. But if you're a Tesla or a son and you have the virtual power plant concept, so they can actually support the grid and from the utility perspective it's a lot easier because they talk with just one entity and they control all their assets, but is still like fuzzy the environment over there. But I know the VPP, the virtual power plants, that concept addressing that. I agree. I think the VPP is an exciting concept, but you also have to think in the future as we get more and more residential PV on the system, it's going to have to become dispatchable. And so I don't know exactly how that's going to play out, ut obviously you can't generate more power than the grid is demanding and it's not too far in the future where that could happen on some days.
Excellent. Dick, one more question for you. What permits did you need and how long did it take for you to get them or complete the construction? as there any special permitting issues o ensure that the system can operate in an island mode? I assume that means like off, some semi off grid, I guess because you're not completely island? No, because we had the smokescreen of having a utility interconnect. So the permitting was very straightforward and went through completely. Of course, all of the PV system has an anti islanding capability on it to protect the grid and they were aware of that and that worked fine and the gateway for the battery the same.
So from the perspective of the city, regulators, and utility, there was essentially no problem with the system. So we're running out of time. But I want to ask everyone one final question, and that's sort of how in your minds will the grid look in 10 to 20 years? And what issues should we be solving now that are going to affect the grid as more houses become generators of renewable energy rather than just energy consumers? So I don't know Dre you want to go first? Sure.
So I really hope that everything is electrified. I hope we are absolutely done with gas in 10 to 20 years. And yeah, I think the huge challenge o navigate actually is around equity and who gets included in this energy transition and who gets left behind. So who are some of the last people that are stuck with this aging gas infrastructure and having to spend a ton of money to meet their energy needs? So that's something that I hope researchers and everyone continues to focus on.
And that's my piece. I'll pass it on, Gustavo, what do you think? Yeah, to me it's two points. One, I think is what Dre mentioned.
The equity part is something very challenging, especially when you try to look at the electrical code and see the permits and all the installation requirements. You have to do a lot of work to make sure that all the homes are actually in good standing from the electrical standpoint, and the second one for me is more the impacts on the distribution infrastructure, right? So electrification of all the appliances is fine, but then we need to couple that with the grid. And so if the infrastructure can't support that, so a lot of transformers is going to be overloaded and I get zero fault utilities issued a report where they say that plus how many heaters, transformers and so on will need to be replaced if they reach their goals. And also the EV penetration and the impact on the infrastructure I think needs to be really, it's a problem that really needs to be thought really carefully about it. Dick, any last thoughts? Yeah, I agree with all of that.
I think the you know, what we explored is the is this closest to off grid end of the spectrum. And certainly we're not placing any stress on the utility infrastructure by doing that, but it's clearly probably not the most cost effective solution. Alternatively, you could have all of the generation and storage assets at the utility side, and that's probably not the most cost effective. And I don't think you can, you can figure this out by just doing Excel spreadsheets. So I think we have to have everybody trying everything and see what we get traction with.
So in the next ten years, I would like to see people experimenting across the spectrum on how we solve this naughty problem of getting to zero carbon. Thank you all again for joining us. Thanks. Special thanks to Dick Swanson, Gustavo Cezar, and Dre Helmns for taking us on this awesome virtual field trip. I'd also like to thank to all of those who have helped put this event together, especially behind the scenes. I'd like to particularly thank Sarah Price and Marianne Fives, who have been working diligently behind the scenes to make sure today went off without a hitch.
There was a lot of technical things we needed to to iron out. In case you missed our first virtual field trip to the International Space Station, where we spoke to the astronauts, Kayla Barron, or our second virtual field trip, where we explored how energy storage increases community resilience by touring the Bad River Band Reservation, who have deployed a microgrid, which hosts the largest lithium ion battery project in Wisconsin and boasts local site and tribal resilience. You can check both of those field trips out at secretlifeofenergystorage.lbl.gov. . I believe it's also been put in the chat. A recording of today's field trip
and information about upcoming ones are also available on the same website. f you have any ideas for future field trips, we'd love to hear from you and we hope to see you at the next virtual field trip. Thank you very much.
2022-07-15 00:25
