Dear reader, part 1 (generators)
after we looked at all possible facts regarding generators which rely on the principle of the ICE (internal combustion engine), now we take a closer to batteries for use as backup power system and beyond 'first aid'.
First and foremost it has to be said that batteries, unlike generators can't produce electricity, but they simply store it. Batteries need to be charged first, have a certain capacity of storing a certain amount of electricity, usually by chemical components which react while being charged or discharged. Although not a 'battery' by the conventional definition, it's also possible to store electricity in the form of kinetic energy: use pumps to pump water from one level to a higher level (charge) and to use turbine/generator combinations to let the water flow to the lower level again (discharge). This method is usually forgotten, because it is mostly applied in large scale hydro-electrical projects, which often take years to construct and could cost billions of Dollars. The principle however to use a small local stream for electricity generation can also be used by using a small artificial pond on a hill (higher energy level) and converting it into a easily scalable energy storage system, much cheaper to build and run than relying on chemical batteries, which also take much more logistical effort to put in place for the same amount of stored energy (KW).
In principle even seawater could be used, but that requires components which can't corrode as easily and should only be considered when there's a lack of rain/stream water.
Reminder: always read the safety instructions provided by the manufacturer of your battery/ies thoroughly!
Batteries have the advantage that the can be used to transport electric energy from one place to another where it is urgently needed (the disaster zone). So they could deliver instant electricity without producing any noise or emitting any toxic fumes, but on the other hand they might be much heavier than generators and after their has to be addition equipment at place before the battery is fully discharged. Many chemical batteries don't even 'like' to get fully discharged, since it would have a negative impact on their lifespan and/or their capacity. However there are more modern, but also still more expensive, batteries on the market which can get fully discharged without being damaged.
Fully charged batteries should only be used, when the logistics is able to deliver 'chargers' before the lights go out again. Batteries are ideal for being the center of a reliable, stable and good quality power source. Good quality means that they can deliver in general very stable AC frequencies of 50/60Hz, because they don't have to care about exact RPMs like generators, but on the other hand they need so called inverters to transform their DC current(like 12V,24V,48V) into they widely used AC currents. Just like there are many different types of generators on the market which all produce e.g. 230V AC, but with very different specifications which justify the often big differences in their purchasing price. So the quality of DC to AC inverters also important to know in advance and often the cheapest products on the market aren't sufficient or even dangerous for sensitive kind of power consuming equipment like computers or medical equipment.
The chargers which have to get connected with those batteries at some point should ideally fit the disaster area's prime 'natural energy' source. So it wouldn't make much sense to install solar panels in areas where it's often very cloudy or which are very var North or South of the Equator and it doesn't make sense to install wind generators in areas where there is no wind or just just very sporadic wind. Of course generators can also be connected to larger batteries to recharge them, especially during the initial phase of disaster response when sufficient solar/wind capacity still needs some time to get installed. Even when the primary source of natural power production is fully operational, generators cd remain in place for backup purposes. There are maps available for almost every place on the globe giving often very reliable indications of what amounts of wind/solar energy is locally available. Many people know that solar power is very easily scalable from just one panel of 100+ Watts to whole fields of thousands of those panels (solar plant) with very big (e.g. 500 KW) inverters at their center. Wind energy however is not that easily scalable, although wind generators also start from 100+ Watts (think of small wind generators often used on yachts), but when hundreds of kilowatts or megawatts needed, it makes more sense to order very big (and more efficient) turbines instead of creating an array of smaller ones. In mountainous areas streams and rivers can also be used to install turbine based generators which deliver quick and often very constant power.
Depending on the type of battery used one has to make sure that the target area for their use fits in their operating specified by their manufacturer. Many, if not all, chemical batteries have a temperature range which they can function. And even when operated within those specified limits their capacity can be dependent on the operating environment. Many batteries lose significant portions of their capacity when operated in very cold environments, some can even freeze when it's too cold. On the other hand the can also overheat, especially when charged/discharged with high amounts of amps resulting in extreme cases in fires or explosions. Some batteries can also emit dangerous gas when e.g. charged. That's why older car batteries based on sulfuric acid and lead should be ventilated while being charged, because Hydrogen gas is being emitted during the chemical reaction which comes along with the charging procedure. People have to understand that charging/discharging always invokes a chemical reaction in the battery which transforms the content of the battery from one/several substance(s) into other(s). This often also involves the generation of certain amounts of heat. That's why it's essential not to to short circuit batteries, because the very high flow of electrons invokes a rapid reaction in the battery, which produces gas and/or heat which can result in a fire or even an explosion. Just think about those exploding laptop or smartphone batteries. So it is also wise to store the batteries in places which are
a.) ventilated
b.) not easily combustible
just to make sure that nothing goes terribly wrong once a major mistake happened.
Since all batteries operate on usually quite low DC voltages ranging perhaps from 12V to 24V, it's also a necessity to watch the diameters of the cables used to connect the battery (array) with other equipment. While many people are used to the 'usual' diameters of AC cables, which used voltages many times higher than those DC currents, the cables for equipment to be used with batteries must also be X times thicker (the conductor core, not the insulation!) unless people just want to operator a few LED lights with a few Watts. Rule of thumb: The lower the voltage, the thicker the cable has to be. So it's rather unwise to set up a heavy duty small electrical grid based on 12V technology. When then final AC consumption is 'just' 1000 Watts, some 100 Amps could be flowing from the battery array to the converter (assuming +- 20% loss). So when you use a conventional AC power cable used for 1000W AC (230V!) you can be sure that that thin wire which is designed for 16 Amps will get very hot or even melts and starts a fire ! So when you intend to use kilowatts of AC power, you should think in advance of using equipment which operates on 48V instead of 12V or even higher voltages when more power is needed. There's a reason why 12V is often used in cars while 24V is standard in trucks ! (cable lengths needed and power needs of electrical systems attached to battery)
It was already mentioned that short circuits kill batteries and also often result in fires, so it also makes sense to remind everyone to install circuit breakers (fuses) very near the battery. Just like in cars/trucks there are a number of different fuses installed it should be standard operating procedure to install a fuse box somewhere near the battery (array) in order to prevent mishaps which could also be very expensive even without resulting in a blaze. Batteries aren't cheap and every fuse installed which costs only a few cents could save some big bucks !
Batteries installed along with sufficient solar or wind generation power is very useful 4 enhancing resiliency of vital infrastructure like communication centers or cell towers and also for keeping gas stations operational in the aftermath of a natural disaster. As 'predicted' a loss of communication and refueling infrastructure had a significant impact on the e.g. the island of Puerto Rico. The aid effort couldn't be coordinated without communications (almost the entire island lost cell service & power during/after hurricane Maria hit the island) and since roughly half of the gas stations have been also 'knocked out' and fuel rationing was implemented, the use of fuel based generators also was difficult, if not impossible. The use of batteries is much recommended to make sure that vital infrastructure which relies on electricity keeps on working also during and after disaster strikes. Often the structural integrity of comms infrastructure, gas stations, hospitals and other important cornerstones of modern societies is intact, but the lack of AC power forces those fully intact ,or only slightly damaged structures, to shut down. Batteries can make wind/solar power usable 24/7/365 and should be installed in place at least for backup purposes.
Battery capacity can range from a few Ah (Ampere hours) to many MAh. Very small battery packs are useful 'range extenders' for individuals which use smartphones, tablets, laptops and want to extend their operating hours. Keeping the telephone or tablet 'alive' in the aftermath of a disaster can save lives. When the regular power source (provided by the AC utility company) fails it's essential to conserve as much electricity as possible, so it's a good idea to switch off all gadgets with large displays and a higher consumption in general and to use e.g. smartphones instead. When their internal batteries run out of power it's often possible to recharge them by tapping power from switched off laptops or another good idea is to have a 12V USB charging unit for car use at hand and to use the car battery as a backup power source for vital communication. If the roads are blocked or inundated, bridges destroyed and thus the car rendered useless and especially when the fuel tank is empty, it might be a good idea to disconnect the car battery in order to save power which is otherwise consumed by car electronics.
In order to be able to communicate after the AC power comes down the best idea however is to have one of those external battery packs with built-in solar power at hand. They only cost a few Dollars/Euros and can be used for indefinitely, if exposed long enough to the sun. Small and large scale solar based solutions are a bit trickier however, when used during winter in areas outside the tropics, because daytime hours are limited, weather also often rather overcast, and so the amount of sunshine to recharge the batteries might not be sufficient. In Norther Europe for example the month of December only produces 1/6th - 1/8th of solar power available during July. Near polar regions of our planet the amount of sunshine hours during winter can be just zero, so solar power generation doesn't make any sense.
The 'big ones'
Besides the small ones which are sufficient for the power use of one or several small devices like phones, tablets or laptops, there are the ones now being produced in significant number which can power an entire household. One of the more well known manufacturers is Tesla and their product called 'Powerwall'. There are also other well known manufacturers of inverters or offgrid solutions in general either selling own batteries along with their AC/DC/load&charge control hardware or whose hardware can be combined with other batteries sold separately. As of publication of this blog article the costs of the battery is still the main component of the overall purchasing price of such a unit which is necessary to meet your home's (or office's) power needs. Generating stable, reliable AC power isn't that easy and good quality solutions which are also safe(for users and grid operators/service personnel!) are still costing some money. The Powerwall product has currently some 7 kWh of usable energy which is sufficient, since most of the power generated during the day e.g. by solar panels on the roof will be consumed directly before it gets stored in the battery.
When an apartment block, or an office building needs to be powered by a combination of wind/solar electricity generation and a battery, we are talking about some hundreds of kWh or even Megawatt/hours. Those storage capacities can either be achieved by creating an array of smaller units or by using a big battery system, often also less costly than a myriad of smaller systems. One disadvantage of large systems in the event of a disaster is that they might nor be 'in stock', but most be build first according to customer's specification. They perhaps also need some special logistics, because they're large and heavy and if that would be no problem to get those 'beasts' to their destination during normal circumstances, it might be too difficult once roads are damaged or completely unusable. Many of those might even be too heavy for helicopter lift.
Battery Energy Storage Systems: A Cost/Benefit analysis for a PV power station [NREL,pdf,17 pages]
Battery Energy Storage Systems (BESS) [ABB,commercial]
Products [Younicos,commercial]
World's 10 Biggest Bulk-Storage Batteries [Forbes,photos]
Lifespan
As indicated earlier, some batteries may live longer than others, while some allow to be fully discharged in use, there are others which just allow to withdraw some 50% of charge. For the non-expert batteries like car (or starter) batteries and others used for backup power look similar, but they differ not only inside, but also those used for backup power or electric vehicle use are often many times as expensive as car/truck batteries. Starter batteries are mainly used for starting the engine of a car or a truck and therefore they are optimized for delivering as much amps as possible for a short time before they are recharged again by the small generator also installed somewhere under the hood. So those batteries never get even near fully discharged, but usually they only use a few Ah before the motor kicks in and they are recharged all the time as long as the motor keeps running. Those car batteries often have a problem of holding on to their stored capacity when not in use for a couple of weeks. They lose stored electrical energy even when no other power consumers are attached to them and that's another disadvantage when thinking of using them for backup power. Of course when people live through the aftermath of a major disaster they are glad to have at least some electricity stored earlier, but using much cheaper car batts for the explicit use at home as a source of backup power isn't a wise choice. According to many 'offgrid freaks' it makes sense however to use refurbished or not too old batteries intended for use in forklift trucks. You have to be familiar with the number of Charge cycles in order to know how long your battery will last. Always compare differences in purchasing costs also with the differences in those charge cycles. Often a battery that seems more expensive at first glance, could in fact be cheaper in the long run. In general if you are familiar with what's 'good' and what's 'bad' for the type of battery you use and treat them accordingly the likelihood that they last longer will increase.
Weight / power ratio
During emergencies the main priority of battery use is for home use backup power or relying on battery aided small grid solutions. So the weight / power ratio isn't that critical as in vehicle use. Size of the electricity storage solution isn't the main priority either, but on the other hand the batteries used should be easy to install, save to operate and should require just a minimum of maintenance. (When roads/ports/airports are inoperable spare parts and support personnel can't get to the battery site easily)
Battery capacity vs solar/wind production capacity
Not easy to determine, since it all depends also on local conditions for both and when the emergency power supply must take over the task of the regular power grid. The battery technology used is also important since some batteries aren't lasting long if they are discharged more than 50%. In your calculations you shouldn't allow to use all of your battery's nominal capacity. Regarding solar power in general the winter months require a solar capacity several times that what is needed during the summer time. If possible it's better to install more production capacity than needed. If the batteries are fully charged the charger units cut off the DC power and they can't get damaged. Some examples for small off-grid systems in some world regions will be added later. Some wind/solar specifics will also be added later.
transport safety
Since some airlines already experienced problems with even smaller types of Lithium based batteries installed in smartphone and laptops, but also some Boeing 777 had experienced smaller fires ignited by faulty on board Lithium batteries, some restrictions concerning air freight could apply. All acid based batteries, which are not 100% sealed also pose a danger, especially when tilted and the corrosive liquid could flow out and react with other materials (metals) nearby the battery. So they also might be subjected to restrictions imposed by the airlines. Some more research on this subject will done and results will be added later.
Where to store ?
It's recommended to place the batteries in an environment that can't incinerate, which is dry and where nothing can fall onto the batteries and short circuit or damage them. A dry place means also not only dry during the dry season, but also high enough to prevent future inundations. Especially in the tropic regions of the planet not only flooding from heavy rain downpours could result in local flooding, but in regions near ocean coasts there is also the risk of storm surge occurring during heavy storms. Setting up backup power system should also mean to think ahead of possible dangers. If you put your batteries on an elevated position make sure the construction platform is strong enough for the additional total weight of batteries,cables and additional extra equipment needed to keep the system running. In areas with strong storms or tropical cyclones make sure that the building you put your batteries in is sufficiently ventilated, but strong enough to withstand the impact of flying objects/debris picked up by high winds. Even little pieces of flying metal debris could short circuit your battery system and could cause significant damage/destruction of your battery system.
Fire risk
Since those batteries have often have very flammable and/or corrosive and/or poisonous substances inside, a physical breach of their container either by impact or fire should always be treated with caution. Make sure to protect yourself from those chemicals or byproducts which can be in the area of the batteries when they are exposed to a fire. Read before accidents happen, what to do in case of a fire and especially what fire extinguishers are appropriate and which ones you should never use, because their chemicals would react with the chemicals inside the battery.
New developments
Energy storage, and especially batteries underwent some significant progress during the last couple of years and research doesn't stop. What also matters for the breakthrough of battery storage is the broader availability of such batteries due to increased production and falling prices are also a result of that development.
The rise of electric vehicles has impacted the market for all other (ie home) storage solutions and continues to do so:
Nissan launches British-made home battery to rival Tesla's Powerwall [Guardian, May 4 2017]
Redox flow batteries
Redox flow batteries are a bit different from 'usual' batteries, because they consist of two storage tanks connected by tubes and pumps. They are highly scalable and the fully charged liquid could also be pumped from e.g. a ship into the storage tank. (see: Vanadium redox battery,below)
The different kinds of chemical batteries explained:
Lead–acid battery [Wikipedia]
VRLA (gel) battery [Wikipedia]
Lithium battery [Wikipedia]
Nickel–metal hydride battery [Wikipedia]
Sodium-ion battery [Wikipedia]
Sodium–sulfur battery [Wikipedia]
Vanadium redox battery [Wikipedia]
Na-ion batteries get closer to replacing Li-ion batteries [Phys.org, Mar 3 2015]
Hydro electric power storage
If power storage is needed and some hills are nearby it might be a good idea to explore the hillside in order to determine if it is suitable for creating a pond large enough to hold sufficient amounts of water for producing the electricity needed when the primary generation source (wind/solar/generator) doesn't produce. A system consisting of two tubes with sufficient diameter for water transport uphill/downhill has to be installed. One tube connected to a pump capable to convert electricity into water pumped onto a higher (energy) level, and the other pipe which leads to a turbine connected to an AC generator. The advantage is that this solution is scalable (the bigger the pond, the larger the amount of energy stored), it's relatively cheap, reliable and easy to maintain. it's not 'rocket science' and can be installed probably without the help of experts from outside. If a disaster area has sufficient amounts of rain water or a stream nearby the water can be used to temporarily store the electrical energy in the form of kinetic energy. On a large scale those kind of storage lakes with power turbine/generator combinations are also being used to stabilize a power grid during times where large amounts of additional power has to be 'pumped' into the electrical grid in order to match demand peaks. Within a few seconds after opening the gates water flows downhill and let the turbine spin. If the storage pond or lake is large enough it can deliver power over hours. In times when there is a surplus of electricity generation (at night or on Sundays) the pumps can used to create additional power demand and to pump the water uphill again until it is needed the next time.
You will find some more info (commercial and in general) about those systems attached.
Water turbine [Wikipedia]
Micro hydro [Wikipedia]
Hydroelectric power on a residential scale [The Greenage]
Microhydro Myths & Misconceptions [Homepower, December 2012]
Inverters (DC>AC)
Please note: AC (100-500V) currents are potentially lethal and you should make sure that all equipment purchased is of good quality. The solutions displayed here as examples are 'state of the art', but of course there are also similar and perhaps much cheaper products on the market, which will also work, but always make sure that those are certified for electrical safety. Since wrong wiring, lack of electric expertise could also result in injuries or even death, only let qualified (&experienced) personnel install that equipment. Read instruction manuals for installation and operation thoroughly before installing those.
Battery Inverters [SMA(GER/UK/USA),commercial] (range:KW-MW)
Inverter/chargers [Victron(NL/UK),commercial] (range:500W-5KW)
Solar/Wind power generators
There will be an additional blog entry about those products later
Battery use during/after disasters
There are some reports regarding the use of battery storage systems already in place when a disaster struck or as response to widespread power outages in the wake of a disaster. Those buildings or parts of a power grid which did have battery backup power installed are often the only places with a reliable source of power and generators even when they are already in place sometimes have problems starting after a long time for several reasons.
During Irma’s Power Outages, Some Houses Kept The Lights On With Solar And Batteries [Fastcompany, Sep 13 2017]
Tesla is sending hundreds of battery packs to Puerto Rico in the wake of major hurricanes [Business Insider, Sep 30 2017]
Tesla to send more battery installers to Puerto Rico to restore power [Reuters, Oct 6 2017]
BACK UP POWER REQUIREMENTS FOR SERVICE STATIONS [cga.ct.gov, re Florida, Louisiana & California]
There are sometimes unfortunately also criminals who don't respect the need for backup power:
Thieves target backup batteries in cell towers in southern Ontario stumping police [CBC, Aug 29 2017]
Saw some credible report regarding US Virgin Islands and stolen generators at cell tower sites in the wake of hurricane Maria, too.
World's first solar-powered gas station comes to Australian Outback [autoblog, Mar 15 2016]
related links:
10 home batteries that rival Tesla’s Powerwall 2 [Business Insider, May 18 2017]
IKEA takes on Tesla by launching its own home battery [Wired, Aug 2 2017]
note: as always it's likely that this blog entry will get some updates during the next couple of days
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