So today let's talk about generators. So I assume you're looking into generators for your off-grid energy system, and you've seen that there is a distinct difference between the newer inverter type of generators and the conventional generators. Now the inverter types come at a significant price increase, though the sales people and the brochures will tell you that they also come with a lot of advantages, and that they're worth spending extra money on it. Now the question is to which extent is this just fancy sales talk, and what kind of real-life advantages can you expect when you're operating the inverter types and therefore is it worth spending your money on them. So my goal in this video is to provide you an overview of the facts regarding inverter versus conventional generator technology, and kind of poke through the marketing stories around them. And I want to make sure that you have the relevant information that you need, in order to make the best decision for whichever generator is best for your setup. Before we go ahead let me introduce myself: My name is Jesse, I am a renewable energy engineer and I'm specialized in battery-based off-grid solar energy systems. I have run companies in the design and installation of these setups, I've held the position of Energy Officer for the United Nations, and I founded a company solar solution through which I share my knowledge and expertise through videos such as this one, seminars, online articles and through direct personal support through services on my website. So in order to keep this video brief and focused, I'll cut it up into four sections: First we look at the generator basics, we'll then compare the inverter versus the conventional type of generators, We’ll briefly look at the different fuel source options that you have, and I'll wrap up with conclusions and a few specific tips for you. So let's start by looking at the generator basics. I'm going to try to explain this to you in less than a minute. So it started with this Englishman called Michael Faraday in 1831; He figured out something which is now referred to as Faraday's law. So basically what it says is that if you take a magnetic field and something that conducts electricity, such as a copper wire, move the copper wire through the magnetic field and you have created an electric generator which makes electricity. There are different kinds of electrical generators, such as the ones that produce alternating current , referred to as alternators, you find them in your car for example, or the ones that produced direct current, called dynamos: You can find them in portable devices such as radios such as the hand-cranked or flashlights. Now those are the basics of generators and I think I managed to do it in less than 60 seconds, right? So let's move ahead and actually start comparing the inverter with the conventional type of generator. I'd like to start by looking at the conventional type first. Now this type typically consists of an internal combustion engine that is driven by whichever kind of fuel source, and this is than coupled to the actual electrical generator and the two of them together we refer to as the generator or the genset. The result of the two components still being kind of separate, is that the whole unit together can be relatively heavy or bulky. So I want to explain to you the difference in quality of electricity produced by a conventional generator and an inverter generator, and I'm going to try to do that by drawing an analogy between making electricity and making French fries. So the conventional generators try to produce a high-quality electrical output, so perfect French fries, by for example controlling the engine speed and therefore the frequency or the internal magnetic field and therefore the output voltage and on average is doing a pretty good job, but whenever you're changing something , the loads on the generator such as by turning on or off your air conditioning, your cooker or whatever, now you can hear that change in sound like …….. So whenever that happens you are actually not making perfect French fries but for short period of time you're making kind of messy uneven potato wedges. So just remember this analogy and I'll get back to it later on when I compare it to the inverter generator. The other things I'd like to mention is that yes they can be fairly noisy because they run at the same speed all the time. It's also important to realize that you get the best fuel efficiency out of them if you run them at full load. If you run a generator at 50% of its load or less you can spend twice the amount of fuel per amount of electricity produced, compared to when it's under full load. So real life numbers that you can expect is that generators under full load will cost you around $0.50 per unit of energy produced, compared to a generator under lower loads will cost you around $1.00 per unit of electricity produced. So now let's look at the inverter generator: So the basic layout is somewhat similar to the conventional type, but now what they've done, is that instead of having a separate engine and a separate electrical generator, they really combine it into one unit. So they do this for example by using the flywheel of the engine and then using it to directly produce electricity. So the obvious result of this is that the overall weight of the unit and the volume, can be drastically reduced. So now let's look at how the electricity is being produced and how the quality is being controlled. So this is where we get back to the French fries Topic: The inverter generator takes the power produced and kind of messes it up to mashed potatoes, and then produces this perfect French fries: It takes the AC power being produced, breaks it down to the DC power, and then through an inverter builds it up to AC power again. Therefore your output is very controlled, very stable, a perfect sinus waveform: Frequency, output voltage, high-quality electricity: Perfect French fries. So because of this the inverter generator can run at lower speeds and therefore being less noisy, and if you run it at lower speeds and lower loads, the fuel efficiency will be somewhat similar to the fuel efficiency when running it at higher loads. So now the results of all of this is that an inverter generator can run at lower engine speeds, while still providing with high quality power, because you can run it at lower engine speeds: It can be less noisy if you're running it at lower engine speeds, your fuel efficiency will be still somewhat similar to that when you're running it at full load. So let's briefly look at the different kind of fuels that you could consider. So there's three different ones: Basically you've got your diesel, you've got your petrol, gas, gasoline, whatever you call it, and the third one is LPG, bottled gas, propane, they all refer to the same thing. The energy density of diesel is slightly higher than that of petrol, and because diesel engines burn fuel more efficiently, you can typically expect a twenty to thirty percent reduction in the price that you pay per unit of electricity produced. The energy density of propane is significantly lower than that of gas, and often when you look in the details, what you will actually pay for your propane if you're using the conventional bottle exchange services, is that you'll end up paing twice as much per unit of electricity used, when you compare using propane versus conventional gas or petrol. There are also a few externalities that I would like to mention, such as propane burns and handles just a lot cleaner than the liquid fuels, but the liquid fuels have a higher energy density, so you need less storage space. And diesel engines, they require higher upfront investments, they are heavier and noisier, but their service life is just really amazing if you compare it to gasoline engines. So this brings us to the conclusion and tips: I'll give you four conclusions and two tips. So conclusion number one is that yes, definitely the inverter generators will give you a great advantage over the conventional generators, when you're looking at the fuel cost under varying loads, which links directly to the second conclusion: Which is that if you're using your inverter generator under full load, and you're comparing it to your conventional generator under full load, then they produce kind of the same amount of noise: They consume the same amount of fuel it's just that the inverter generator, can possibly produce a little bit higher quality of electrical output. The third one is that for inverter generators due to the integration of components, their weight is definitely less than the conventional generators. And number four is that operating your generator on bottled gas, is due to the higher price still less cost efficient when compared to running it on conventional petrol. So my first tip is that if you're using an inverter generator, and you have turned off the Eco throttle mode, then you've basically reduced its functionality to that of a conventional generator and you've lost all the advantages that come with an inverter type of generator. The second tip is that if you haven't made up your mind on what you want to go for, inverter or a conventional type of generator, if you know that you'll be using a generator under full load and the loads will be fairly constant, you know they'll perform basically the same so you might want to consider not paying the premium for the inverter type of generator, which will basically do the same as the conventional generator. Ok so now a question for you: If there's something that I haven't covered yet, and which you would like to learn more about, let me know in the comments below and I'll use this as inspiration to provide more videos for you, and for others. Of course you've got all the great options of sharing, liking, subscribing, et cetera. I really hope you enjoyed this video and I'll see you in the next one.
