How To Build a Microgrid

A microgrid is a relatively small power grid which takes electricity from a source, stores it for use, and distributes it to devices. This can range from the size of a town to a neighborhood to a single home. The principles are the same.

Based on this definition, chances are you already have one or more microgrids in your life. In a way, your car is like a microgrid. It generates power, stores it, and then distributes it to devices like cell phones which plug into it. RVs and tiny homes area also good examples of microgrids.

Step One: Sizing Your Grid

The first step is to determine how much power your grid needs to deliver. A single home will typically draw an average of approximately 1,000 watts. But then again. An air conditioner can easily draw at least that much. If you’re not sure how much power you need, check out this helpful article on estimating power requirements before you continue.

Step Two: Picking Power Sources

There are two broad categories of power sources for microgrids; renewable and non-renewable. Renewable is typically going to be more expensive initially and much cheaper in the long-run. Non-renewable is often cheaper initially but more expensive in the long run.

The most important thing to consider is how much power you need. The math gets a little complex, but a good rule of thumb is that you should never plan to use more than half of your capacity. If you calculate that you need 1,000 watts, then you need your grid to be capable of producing at least double to triple that amount. There are two big factors at play here. Power ratings are typically given in terms of the root mean square of the actual draw. This is a sort of logarithmic average which means the actual requirements can jump momentarily well outside the official number.

The other related issue is inductive loads. Things like fans, air conditioners, refrigerators, and stereo equipment will often draw 300-400% of their rated wattage while they are spinning their moving parts up to speed. That 100 watt mini fridge will likely draw 300-400 watts just for a moment while it’s starting up. The effect of this is that when you first flip the switch and turn your grid on, it can experience much higher demand than you may have estimated. If this amount is too high, the breakers will simply trip  and the grid will shut back off. Any momentary interruption in power can lead to everything on your grid drawing very high current when the power is restored, multiplying your troubles. So make sure to plan for more capacity than you think you will need.

Non-Renewable Sources Of Electricity

The classic example of a nonrenewable power source for a microgrid is the generator. Getting a generator is typically a good place to start, as renewable sources can often face periods where little to no power will be generated. In those moments, a generator can help fill the power gap.

 

Probably the most popular generator in the microgrid community is the Honda eu2200i. This generator is very quiet and very reliable. It can put out 2200 watts as the name suggests. They can also be daisy chained to add more power, though 2200 watts is more than enough power for most homes or RVs, and likely enough for a small community of campers at an event like Burning Man.

 

This little guy is very popular as a white-label product. Many stores like Harbor Freight and Home Depot will sell these under different brand names. It puts out 1,000 watts. I found one of these for just $50 with a two year warranty and I’ve gotten years of use out of it. I primarily use this to power my DJ gear when I do parade floats or off-grid events. This would be perfect for many smaller microgrids such as a single RV/camper at an event like Burning Man. In a pinch, it could easily serve as a perfect emergency backup option for a medium sized set up.

Renewable Sources Of Electricity

The cheapest and most popular example of a renewable source of electricity today is solar photovoltaic or “solar panels.” Before the current trade war, and presumably afterwards, decades of solar power can be had for just $1/watt. This is much cheaper than the cost of a generator, considering ongoing fuel prices. Today, you can typically buy solar panels for about $1.50/watt. But this price will likely go back down once our current economic situation is resolved. Even with this price jump, solar is still the cheapest source of electricity today, though sunlight can not always be counted on.

Here is an example of the type of deal that can be found today on solar panels. Amazon is selling these 100 watt solar panels for about $136 each. This is much cheaper electricity than going the generator route. If you wanted to go 100% solar instead of the 2200 watt generator I linked to above, you would need to spend $2997.44 on panels. This is equivalent to the cost of using that generator for just a few weeks. It’s a no brainer. BUT, you will likely need to make enough power to compensate for dark periods or augment your solar power with a backup generator in case of cloudy days.

Wind power is another excellent option. Wind gets mixed reviews but my understanding is that it can be very reliable and very long-lasting. For approximately the same price as solar, you can get the same amount of power. Each of these turbines produce 1200 watts. A pair of them produces more power than the popular generators linked to above.

Keep in mind solar power depends on ideal conditions with the sunlight and wind power depends on ideal conditions with the wind. These are both excellent power sources but there will always be darkness and the wind doesn’t blow all the time. The key is proper storage and having a backup generator.

Step Three: Storing Power

There are two main approaches to the topic of power storage in the context of microgrids; lead-acid and lithium.

Lead acid batteries often seem like a simpler solution. Simply hook them together and hook up a charger and inverter and you’ve got 120 volts! The problem is that in practice, these batteries can take days to recharge and you can only safely use up to half of their capacity (assuming they are deep cycle and not standard lead acid) before they start to take damage and fail. In the best case scenario, these batteries will only get a few hundred charge cycles before they fail. My advice is not to use lead acid batteries.

Lithium batteries charge very quickly and hold lots of power. These are the batteries in your cell phone and laptop. There are tons of great, simple products which solve the power storage problem using lithium batteries. On the small scale, there are USB battery packs. On the larger scale there are Yetis and the many cheap duplicates available online. These will all recharge from many sources and provide power as needed. This is the best way to store power in a microgrid in my opinion.

The Yeti GoalZero 3000 Lithium is a perfect example. This simple box will recharge from solar panels, generators, a standard plug-in, a car, anything. And it stores 3,000 watts for your microgrid. Then you can plug your devices, RV, or even your house into it. These boxes also come in smaller wattages, all the way down to 400 watts which is what I use for my personal microgrid at burning man.

There are many cheap duplicate products for the Yeto GoalZero line of lithium batteries. This is the one I use. It stores 370 watts which it can accept from solar panels, generators, a car, a plug-in, anything. Then it provides that power through USB and a 120 volt outlet. This is an excellent option for a small camping set up or essentially anyone who isn’t trying to refrigerate anything. In my case, this battery pack allows me to charge my phone over a hundred times, inflate my mattress, and run lights in my tent as well as christmas lights around my tent while camping for over a week at burning man.

If you visit the amazon page for this battery pack, you will see there are hundreds of very similar products, all of which will cheaply solve the storage problem using lithium batteries which recharge quickly and provide lots of power when you need it.

Example 1

 I’m going to a music festival and I just need to recharge my phone and laptop a couple times during the trip.

Easy! Get a USB solar panel and a USB battery pack. This will provide you with more than enough electricity for your needs! I have linked to the ones I have. You could probably go with smaller options than these suggestions depending on your needs.

Example 2

I have a yurt (or a shiftpod) and simply want to run an air conditioner for a while to cool it down at night, while also recharging my phone and laptop. I’m tired of running it off of a generator. It takes too much gas and its not sustainable!

A small air conditioner like this one will be more than enough to cool a space this size. For cooling a space with less than 300 square feet, a 5,000-10,000 BTU air conditioner will be sufficient. The rule is that your air conditioner will need about 1/10 the BTUs in watts while running, and double that amount when starting up. The air conditioner I linked to above is rated at 8,000 BTUs, so it needs 800 watts while running and 1600 while starting up.

This is a perfect job for a Yeti GoalZero 1000. This battery pack will allow the generator to start up and run for about an hour on a single charge. This should be plenty of time to cool down a space this size depending on the materials the shelter is made of. Alternatively, the Yeti GoalZero 3000 will run the air conditioner for almost four hours on a single charge.

You can use solar to recharge your battery pack during the day. Nine solar panels will do the trick. Assuming you use the ones I recommended, you can connect them to the Yeti in sets of three, using these adapters.

Example 3

I need to provide power to a medium-sized community of 150 people at burning man. Each person is limited to ten watts of usage. (They can only use LED lights or charge small devices.) We have a generator which we usually use, but we want to use some solar to take a bite out of our fuel costs.

Solar is the way to go! 150 people limited to ten watts each is just 1500 watts. I would pick up a Yeti GoalZero 1000 for $1300 (or under $1,000 at Costco). This can put out 1500 continuous watts, and double that during surges. This should more than meet your needs, but you could go with a larger battery like a Yeti GoalZero 3000 if you want to be extra comfortable. The larger one has the added benefit of wifi monitoring, so you can monitor power consumption and watts available from the comfort of your tent.

To charge this lithium battery pack, you can use 9 100w solar panels at $136 each for a total cost of $1224.  This is likely plenty of power to refill the battery, but you will still have your generator to fill any gap due to darkness or over-use. If you wanted to increase the amount of power your community can use, simply build two or three of these solar microgrids.

You can plug your existing distribution system into this battery pack and you’ll be up and running.

This would have a total cost of about $2,224 and eliminate most future fuel costs. If you end up needing to use the generator to meet demand, simply add a few more panels next time. This estimate does not include hardware related to mounting the panels and connections between the panels and the Yeti.

This solution likely breaks even in the first year.

Micro Grids and Burning Man

Elon Musk famously came up with the idea for Solar City while at burning man, observing the ubiquitous microgrids which power the temporary city. Every home should work this way, he reasoned. At Burning Man, each city block has many microgrids. They range from very small to very large, and they take many forms. There are also several online communities devoted to discussing issues related to these microgrids at Burning Man.

Incidentally, nearly a hundred billion dollars of venture and philanthropic funds are slated to be poured into the development of microgrids to electrify the developing world in the coming decades. Throughout human civilization, we are seeing a rise of microgrids taking over the work traditionally done (or not done) by larger civic grids. Building civic grids which power large areas is enormously expensive and very technically complex. Many governments in the developing world are not able to do this. Maybe people simply choose to manage their own resources and live off grid, more sustainably. There are any number of reasons why a microgrid is the best solution to power needs in many situations.

Burning Man offers a unique and valuable testing ground for this technology which fosters innovative solutions for this important problem facing humans everywhere. I have an interesting perspective on each of the three types of microgrids I will explain in this post.

What Is a Microgrid?

I like this definition from Wikipedia;

A microgrid is a localized group of electricity sources and loads that normally operates connected to and synchronous with the traditional wide area synchronous grid (macrogrid), but can also disconnect to “island mode” — and function autonomously as physical or economic conditions dictate.

In this way, a microgrid can effectively integrate various sources of distributed generation, especially renewable energy sources, and can supply emergency power, changing between island and connected modes.

For our purposes, I will define a microgrid as a system for powering multiple devices which may use batteries to temporarily store electricity, and which can draw power from many types of sources including generators, solar panels, or other grids. We will see that this definition allows us to consider lots of interesting examples.

The Neighborhood-Scale Microgrid

At Burning Man, I camp with Comfort & Joy. At Comfort & Joy, we have an area approximately the size of a city block where over 150 people live throughout the Burning Man event. We are also visited by many thousands of people who participate in our events and community spaces. We have a relatively complex challenge with our microgrid. We need to power many large performance art projects, a gym, several event and community spaces, instant-hot showers, and a full commercial kitchen.  This is no small feat!

The infrastructure is pretty straightforward. A large 20kw diesel generator is the primary power source. This runs to several spider boxes which distribute the power around the camp through standard extension cords. Each tent has power running directly to it.

Most Burning Man camps have microgrids which work in much the same way. Some camps have many RVs which need higher loads and more spider boxes to distribute power, but other than that, this layout is essentially the standard format for the neighborhood-scale microgrid, both at Burning Man and the world outside.

In the future, the biggest potential improvement would be adding batteries and a renewable energy source such as wind or solar. This would replace the diesel generator as the primary source of power. It would mean becoming less reliant on polluting fossil fuels, and less reliant on the generator as a large single point of failure. Many camps are already using hybrid-diesel/solar microgrids like this.

The Home-Scale Microgrid

Comfort and Joy is an example of a camp with a microgrid about the size of a city block. What this means is that I have a tent with all my stuff inside, and an extension cord running out to our neighborhood-scale microgrid. I plug into that to get power. In turn, I use that power for my devices, costumes, lights, to inflate my mattress, etc. This is an example of a home-scale microgrid (or in this case tent or RV).

Many camps are less organized, and have no neighborhood-scale microgrid for campers to plug into. In those cases, each tent or RV will often have a generator, wind turbine, or a few solar panels to provide power. This power is usually stored in batteries, and then used for the home’s needs. This is analogous to off-grid tiny homes or cabins. In fact, many tiny homes make the trek to Burning Man already including their own home-scale microgrid.

Storing electricity is a challenging problem. Most people will try to use lead-acid batteries such as car batteries or deep cycle batteries. These have many disadvantages. Setting them up and using them is technically complex and often counter-intuitive, especially if the microgrid is using more than one battery. Lead-acid batteries will also require almost a day of solid charging to get to full capacity. This just isn’t possible if your power source is solar or a generator. Both will always face interruptions due to dust, leaving your system uncharged.

A better way of storing electricity is with lithium batteries. These are the same types of batteries found in cell phones and laptops. They charge very quickly and provide a much simpler solution to the problem. The downside is that they can be slightly more expensive, but luckily there is a whole industry around products that solve this problem. The big player is Yet with its GoalZero Lithium battery packs.  Products like this make home-scale microgrids a cinch. Lithium battery packs like this will accept power from essentially any source: solar panels, generators, standard electrical outlets, or car cigarette lighters. They store a lot of power very quickly. Then they let you use it via USB ports, standard electrical outlets, or even via cigarette adapters. These products are a very good solution to the power storage problem. In fact, I plan to run my entire burn this year off of one of these without using any source of power such as generator or solar.

Keep in mind there are tons of cheap, excellent alternatives to GoalZero products. Pictured below is the one I am using, the Poweradd ChargerCenterⅡ 370Wh. It is essentially exactly the same as the Yeti GoalZero Lithium 400, but less than half the price. It still has a standard 120 volt outlet, plus USB ports, and it can still accept power from essentially any source: generator, solar panels, or car cigarette adapter. I am using USB-powered christmas lights for interior lighting in the tent. This box on a single charge can power those lights for the entire event while also recharging my cell phone (camera) hundreds of times. I’ll also use this to power some small speakers for BMIR radio and Spotify.

Using USB Is MUCH Better Than Using 120 Volt

Any time we step power up to 120 volts, there is waste. In fact, there is a lot. I the past, I brought a charged car battery to Burning Man which I hooked up to a cigarette lighter socket. I used normal car accessories for all my needs. I even had an inverter to get 120 volts, but mostly I stuck to cigarette and USB connections. Plugging my cell phone charger into an inverter running off of a battery was enormously wasteful. The power savings is huge if you stay at 12 volts instead of going up to 120 volts and then back down to USB through a phone charger or something like that. Just run a car charger straight off the battery!

USB-powered versions of many common electronics are available and they use less power. An essentially identical string of LED christmas lights which plugs into the wall will use a lot more power than one that plugs into USB. More on that in the next section.

The Mobile Microgrid

At Burning Man, every person simply must have a bike. The city is vast. There just is no way to get around without a bike. Because of many hazards at night, everyone is required to cover themselves and their bikes in lights. This prevents many types of dangerous accidents, but it also poses a problem. My first burn, I brought a bunch of Ikea AA-powered Christmas light strands. These worked great, but I went through a half-dozen AAs each day. This is very wasteful, and there is a simple alternative.

You guessed it, USB! This is an amazing and far superior solution to using AA batteries. A simple solar battery pack turns your bike into a mobile microgrid. Just one strand of $7 USB-powered Christmas lights is very bright and can run for weeks off of a battery pack like this. I ended up using two strands just for fun. Having all this power available on your bike also means you can add other cool accessories like bluetooth speakers or plasma balls and of course it can also recharge your devices. A USB-powered microgrid on a bike is more sustainable, more flexible, and less stressful than trying to swap out moopy batteries several times a night.

My Gear List For Burning Man 2018

This year, I have changed almost all my gear. For the first time, I have my own complete microgrid and a double-tent. I also replaced almost all non-rechargeable devices. This year, my burn will be far more sustainable and very low stress. My gear list makes all that possible.

Home Sweet Home v2

Having a double tent was a major priority in order to delay morning sun and heat from reaching me as I desperately struggle to sleep in. I also wanted to maximize my energy independence and improve over my previous

Big Tent: This provides shade and shelter from the elements. Everything but my bike goes inside. It is secured by rebar wit tennis balls on the ends of each for safety.

Smaller Tent:  This is a smaller tent made of dark material which fits snugly around the mattress. It goes inside the larger tent. This small tent provides a dark space for sleeping which is protected from dust and slows the heat from getting to the sleeper.

Self-Inflating Mattress: This is SO handy. Last burn, I had one that needs to be inflated by hand. At some point, it got a slow leak which required constant work to keep it inflated. Eventually we just gave up and slept on the ground. Never again! Just flip the switch and it’s back to 100%!

Two Coolers: These were on sale for just $15 a piece. Each one holds 72 cans!

Two Chairs: I can’t find a similar deal today, but when I bought these two fold-up camping chairs, they were $5 each!

One Cot/ Couch: I got this for free, and I think it will make a great couch or guest bed.

USB String Lights: For energy efficient indoor illumination. These are pretty bright and can run off of a power bank for the entire burn.

Power Source: I have my own microgrid inside the tent running off of this power bank. It can supply almost 400 watt hours which should be far more than I need for the entire burn. It is comparable to the Yeti 400 Lithium which is more than double the price.

For food, I picked up a bunch of meals ready to eat including all of these.

Breakfast:

Lunch/ Dinner:

My Bike v2

I decided to try to get rid of as many battery-using devices as I could. The solution seemed obvious; USB!

Roadmaster 26: This is the same model bike I took to the last burn. They have proven very versatile and reliable. And they go back to Walmart after!

USB Bike Lights: Two strings of these lights run to a dust-proof power bank in the basket. This is able to run the lights for weeks on a single charge, and it recharges via built in solar panel. This technically makes the bike a microgrid in its own right!

Shelf: I added this shelf to the back of the roadmaster. It allows a milk crate to rest comfortable on the back. This makes it a lot easier to bring beer and snacks around with me on the playa.

Front Basket: I added this basket to the front of the bike. While the back basket is great for food and drinks, the front is great for thinks like the power bank, the lock, spare tubes, tools, etc. You don’t want to find yourself in need of these things and not have them handy!

Other Accessories: I found a kit for under $20 at Walmart which contained a lock, pump, bicycle bottle, headlamp, tail light, and a bell. These kinds of kits are usually available and well worth the $20.