Hello, this is Scott Therien with REC Solar, a Duke Energy Renewables company. This presentation is meant to serve as an overview of solar energy with a focus on solar and clean energy for those in the education sector.
A brief note on who we are: REC Solar has been around over 20 years. We’re a full-service shop. That means we develop our own projects. We finance them. We design them. We build them and we operate and maintain them.
A few years back we were bought by Duke Energy Renewables who is now our parent organization through part of the broader Duke Energy Corporation that has been around over 100 years and is one of the largest electric utilities in the U.S. They have invested over $4 billion dollars in renewables to date as part of their large-scale renewable development.
REC specifically has built more than 750 projects across the U.S. We’re headquartered here in California in San Luis Obispo. We also have offices in Petaluma, Honolulu, and satellite employees throughout the U.S. because we are a nationwide provider.
There are a number of ways to measure success as an organization. These are just a few of the metrics we look at when considering the impacts that we make. For example, a generation of our systems to date is basically the equivalent of 21 trillion trees with the carbon sequestered by them.
So, the environmental impact we make as an organization is important to us. It’s important to our customers and it’s good to have a view on the difference we’re making because it is real, and it is tangible.
As a point of order, here are a couple of segments that I will cover in this presentation. I’ll give an overview of the energy industry before I dive into how solar works and some of the components of it. I’ll touch a little bit on storage and microgrids from a high level and then, talk about how schools benefit specifically from solar projects.
First, I’ll be covering the energy industry in general. Here you see the traditional energy grid. It has been this way, and remained mostly unchanged, for about a hundred years where you have these centralized power plants running across transmission and distribution to the end users, residences, commercial businesses, schools, and anyone else who needs electricity. It’s really a one-way flow of energy from the central power plants down to the users.
Now, that has changed with the modern energy grid over the last few decades, but really speeding up more at the turn of the millennium. You still see centralized power plants, of course, and you’ll even see renewable developments there as utilities are looking at other ways to produce energy, but you also see generation sources down further on the grid down where historically, you’d only seen loads or energy users.
So, what this has really done is create more of as bi-directional flow of energy where energy generation and consumption is happening all over the place and collocated at points on the grid. Now, this has really resulted in a lot more choice for energy users, but it has also created some additional complications of how to manage that.
So, what you really have here now is this highly evolved situation where we have all kinds of choice as energy users, but we also have tremendous complexity and confusion around those things as technologies advance and evolve. There is a lot of confusion on how best to approach these.
So, for some of the energy generation sources that are out there, I have broken it into centralized generation for your more typical sort of power plants and distributed generations that are onsite where you have generation at the point where you are using it.
And of course, there is a lot of overlap. The historical large-scale parents we’re familiar with are coal-fired, natural gas, and hydroelectric. More recently you have seen nuclear and geothermal and solar farms and wind farms and the like.
Then on the distributed side, of course, you also see the solar and the wind. Oil and gas generators have been around a long time as backup power. Fuel cells are coming online. Cogeneration has been around.
And you can also see how I have segmented into fossil fuels in blue and renewables in green, which is the way some folks like to think about it. And then, of course, there are these that I have shown in yellow where it is maybe not as cut and dry, or it could be either. You could use a renewable fuel or a fossil fuel to power those.
So, looking at all these choices and complexities, why do we hear so much about solar? Solar seems to be very pervasive. It is and one of the main reasons is simply how accessible it is. It works for the homeowner to put a few panels on their roof and it works for large utility companies to build giant energy farms and everyone in-between.
It has become very cost-effective and so, you see real savings compared to local utility rates in many markets across the U.S. While it is cost-effective, it also provides an environmentally friendly way to source your energy which, of course, is very appealing to a lot of folks.
It’s also a proven and reliable technology. It has been around for decades in broad application when compared to maybe some of the more recent technological advances in storage or fuel cells or biomass or things that are still sort of evolving. Solar has really hit its stride and has sort of stabilized. It has become reliable and widely implemented.
So, given that, let’s talk a little bit about how solar works. You basically have three main components to any solar power system. First, you’ve got the modules, or the panels as they are commonly referred to, and these are really your powerhouse. These are what make the energy out of sunlight.
We have inverters which are sort of the brains of the operation. They are the real electronics in the system where it converts that DC energy from the panel to AC energy that is compatible with the grid and the energy infrastructure within the buildings.
Finally, there is the racking, or mounting, structure which is like the skeleton of the system. It’s holding all the panels up. You’ll see down there that there are three basic types that we usually think of: carports, or canopies, and ground mounts, which can be fixed for tracking, and then, the roof mount which may be ballasted or directly connected to the roof.
Without going into a full lecture on physics, let’s take a quick look at how a solar panel works. It is essentially made from a silicon wafer which is doped in a way that creates this PN-junction. It’s just a junction between two substrates basically so that when a photon hits this junction, it releases an electron and each individual photon becomes an electron loose within the substrate that can then be mobilized across the voltage potential then creating current through the junction, through the cell, and on to the leads of the panel.
When thinking about it in terms of building blocks, the way the photovoltaics are produced is, as these individuals cells that are combined together within the solar panel, or the module, the cells are connected to the series and then the module has two leads, a positive and a negative coming out of the module. Those leads are then strung together. We connect them together to create this series of modules and then, those strings are combined into an array. An array is what we often talk about as a building block of the panels that come together to form the overall system.
So, let’s look at how that system comes together in a residential system for example. So first, you have solar panels on your roof converting sunlight to DC energy. Then two, you’ve got your inverter typically mounted to a wall on your residence that converts that DC energy to AC energy and then, connects with your existing electrical service which is usually a panel board on the outside of your house. That is also where the utility grid comes in.
So, now you’ve got two services coming in, one from the utility – the preexisting one – and then, one from your new solar system. So, you’re usually still connected to that grid service.
Now, when we look at a typical system at a school, it’s very much the same although perhaps a little more complex. You may have some panels up on the roof. Commonly, you also have some on canopies or carports out in the parking lot or playground and those come together. You still have your inverter converting that DC energy to AC energy. Sometimes it’s a larger and maybe pad-mounted on the ground or it may still be wall-mounted or up on the roof.
And then, that interconnects with the existing electrical service there at that building or the campus and that may have some more complex issues. It may interconnect to some EV charges. It may have an EMS, or engine management system, that is controlling HVAC and other load controls. So, that now all comes into play together and then, typically, it’s still connected out to your local utility grid.
So, now to segue into storage and microgrids, which is a related topic you may have also heard about. More and more now you’re seeing solar projects being paired with energy storage or battery storage. Here you are looking at sort of a large-scale one where they come in a C train. There may also be smaller-scale ones, but they are typically filled with batteries and they control system for that in some sort of management system over it.
They are being paired with solar because of this energy you see between those two services. When we look at how that helps, these three graphs will walk you through that implementation to where on the left, we have a typical profile for original energy usage as it stands where you’re getting service from the grid.
Now, when you add solar, what you see in the middle of the data in that blue line, is your load before where you were using a great deal during the day when school is in session and when your building is running a bunch of loads and you have your solar running as well offsetting that and bringing your usage – when you look at it from the perspective of what you’re pulling from the grid – down. It drops that down quite low.
Now, the evening hours – the peak hour rates – where you pay more and more for energy, you still may have some loads there. So, when we look at the right where we add storage, what that storage system is doing is, during the early hours of the day – usage after storage is the light blue line – we actually are charging the storage with that solar energy.
Instead of using the solar energy to offset your usage, we’re charging up those batteries and we’re going to save that energy for later in the day when energy rates for the utility are more expensive. We are going to use that to offset that load on in through the evening, and maybe even after the sun sets, to really knock down those peak rates.
So, basically, what it does is, it allows the earth’s solar energy that is really only available when the sun is up to be dispatchable any time and, more specifically, when the local utility is charging you the most for energy. So, it increases the savings that you would have seen from solar even further by optimizing when you use it.
So, now when we talk about microgrids, it’s a step further even than storage where with a microgrid you have the ability to run autonomously without connection to the local utility grid. Usually, this is done to be able to continue running in the event of a grid outage for any reason or it may be done for other reasons where operating independently of the grid may be advantageous.
But with a microgrid, you may have multiple sources of generation whether it’s wind, solar, or other forms like maybe combined heat power. And then, you often have batteries associated with that to make those generation sources more dispatchable. Then, what you have is a management system that controls not just the generation and the dispatching of that generation, but also the load so that you can chose which critical loads to keep online or turn off.
As I mentioned, usually this is used for handling grid outages where you’re going to keep your emergency infrastructure in place. A lot of times with school districts, that is going to be their servers or their phone lines if they are using VoIP for phone or perhaps if they have an emergency shelter in place, say in the gymnasium, they may keep just that HVAC and those lights on so that everyone can hunker down until the utility grid is restored.
So, now to talk a little more specifically about how schools benefit from solar because there really are additional benefits for a school beyond the traditional savings.
Of course, the primary goal of any school is going to be the education of their students and with onsite generation that helps from a facility standpoint, there is also the opportunity to integrate that with the education. So, a lot of times when you see solar or other projects implemented at a school, you’ll often see some form of curriculum development or STEM courses where the students get to interact either digitally or directly to make their learning process tangible and relate it back to renewable energy or some other form of learning.
Then, of course, there are other ancillary benefits to the students and the staff whether it’s shaded parking to keep their cars cool in the heat, or playground areas often as well.
Then, there is the savings benefit to the broader community as well. Savings to a school is savings to a community generally speaking. Also, when we talked about microgrids with the emergency services those can provide there is also a benefit to the broader community as well.
Schools are really looked to, either in their local communities or even on the national scale in the case of university, as leaders. So, when they take environmental stewardship seriously and are advocates and leaders, it really does have the trickle-down effect to the whole community.
These are a few of the ways we have seen schools integrate their solar project with their educational components. There are lesson plans and experiments that can be implemented around renewable energy in general or specifically around solar if it’s installed onsite. Oftentimes there are events or fairs that are tied in with the solar project and at the university level, we have seen internships and research opportunities be combined with the development of the solar project.
REC Solar is highly active in the school and universities that segment with our solar developments. So, these are some of the ways that we directly support that educational aspect that schools usually like to implement with their project. We do annual publications and guest lecture events. We also host ribbon cuttings and “flip the switch” events or help the school with other sorts of public facing kiosks, media, press releases and things like that. Just little ways to get a little more out of the solar in addition to the benefits of the saving and the environmental benefits but also tying it back to the core mission of the school which is to educate the students.
That concludes our presentation. I hope you found it informative and that your solar projects now and in the future are a great success for you and your community. Thank you.