05 Charging Facilities, EVs & the Grid:
Seven of the currently most innovative methods used in public and private charging of electric vehicles are,
1. For neighbourhood on-street parking there are the Urban Electric “pop-up charging hubs”[1] which offer App operated 7kW fast charging. This is shown how it works in video[2]. The good thing with these pop-up chargers is that they are only visible when they are in use ie. charging a car. The rest of the time they can be recessed below the surface and out of the way. This can be important in older cities like Athens Greece where the pedestrian sidewalks are already very narrow and cluttered.
2. Ubitricity’s “smart cable”[3] is another neighbourhood street parking solution. Ubitricity charging points can be easily installed almost anywhere[4], such as on walls, electricity poles, street lamp posts and even on sidewalk poles/rails. This easy integration into already existing infrastructures coupled with its extremely safe,easy to use intelligent multitasking cable, makes it ideal for public use in cities.
3. A third charging solution for public transport buses, taxis and private use is “Wireless Inductive Charging”[5]. Wireless EV charging can be easily installed into taxi ranks or bus terminals[6] (time of video 00:55) so that electric taxis and buses can easily wirelessly charge along the entire length of the rank[7] while waiting for their next customer or route. With a 5 minute stop, over a wireless charging plate, a BYD “K92 Electric Bus” gets enough electric power to travel 9-13Km[8]. Norway’s capital Oslo is going to be one of the first city in the world[9] to install wireless inductive charging for its electric taxis. If the wireless charging technology was installed along highways EVs travelling up to or over 100km/h or 60mi/h[10] (time of video 16:19) could be charging at a rate of 20kW.
4. Fastned’s rapid charging stations[11] get their power simultaneously from photovoltaic cells and the grid. Their stations provide 50, 175 and up to 300kW[12] rapid charging stations. An 8 charging point station[13] (time of video 05:09) of 4 x 50kW and 4 x 175kW charging points, working simultaneously, would need about 1 MW. That 1to 2MW mostly comes from the grid which it can currently handle, but if this demand increases too much there would be a grid problem. However as the charging units are housed under a roof covered with photovoltaic cells that directly feed the chargers, these can produce enough power to charge up to 3 electric cars[14] (time of video02:40) independently from the Grid.
The City of Dundee creatively implemented such a system[15]. They used a 90kW battery storage unit connected simultaneously to the grid and to a 40kW photovoltaic cell array covering the charging station roof. As a result rapidly charging EVs are being charged by the battery storage unit which itself is being recharged by the photovoltaic cells and the grid.
If the photovoltaic cells used in this type of solution were bifacial solar panels and used solar tracking then on a clear day and with relatively good reflective surfaces they could generate 20% to 50% more electricity[16]. (Time of video 00) Bifacial panels mean that they convert sun energy both from the top and from reflected light underneath[17].
Solar Panels aren’t the only renewable energy system that could be used in these charging stations. Relatively small[18] yet powerful wind turbines[19] like those produced by Britwind[20], can produce from 1 to 80 kW of power.
This use of renewable energy be it solar or wind coupled with a battery system of some sort if needed makes the Fastned or Dundee concept ideal for highway rest areas and parking stations which is how they are currently being used.
5. Some individual, home electric car chargers like MyEnergi Zappi[21] or Wallbox[22] can charge a car at a speed of 7-22 kW. Zappi can be used with power provided from the grid, some sort of renewable energy (wind, sun) or a combination of both. Zappi is fully programmable with Fast, Eco & Eco+ modes. Fast for constant charging using both the grid and renewable energy. Eco with an emphasis on renewable power. Eco+ where charging is only done with renewable energy. Zappi is a smart and intelligent charger as it uses dynamic load balancing[23] (time of video 02:55) which means it takes into account the maximum (power contract) capacity and a house’s main fuse size. By doing this Zappi regulates the cars charging by slowing down or even pausing if needed depending on what sort of energy consumption is going on in the house. It will do this if there is a kettle, a heater, a washing machine, an oven or any other sort of household appliance working which pulls on supply[24] (time of video 12:46). This is done so that charging the car doesn’t overload the house’s power circuit and burn a fuse. All this power monitoring easily shows you how much your car’s charging is costing you at home. If you have some sort of renewable energy at the house, the charging of the car can be free.
6. Portable rapid charging stations. The US SparkCharge[25] is a modular portable rapid charging station. At its most basic configuration it has a 3.5kWh battery and a 20kW power charger[26] (time of video 08:40) making it the equivalent of having a 5 to 10lt jerry can in the trunk of a car. Another 4 battery modules can be added to this making a total of 5 battery units and 17.5 kWh.
When Roadside Assist is equipped with a Spark Charge EV drivers can call them to give enough emergency power till the EV can be fully charged. SparkCharge systems can also be used privately.
The Chinese “NIO Power Mobile”[27] (time of video 10:02) electric vans are another similar custom made portable rapid charging solution for EV driver road assistance.
7. Battery swapping. “NIO Power Swap” battery swapping facilities are an innovation which can help, as the name suggests, by swapping out an empty battery and replacing it with a full one in about 3min[28]. (time of video 06:05) Chinese NIO[29] car manufacturer has already sold over 50,000 EVs, completed 650,000 battery swaps and all of these EVs have combined travel distances of around 800 million miles (1.287475 billion kilometers)[30]. (time on video 01:29) Battery swapping in the USA and Europe is made very difficult because of the plethora of power sizes, dimensions and shapes of battery packs used by different manufacturers. They do not interchange easily or at all[31].
EV’s and the Grid
In many countries the main source of electric power is via a supply system known as ‘the grid’.
The electrical grid works on system frequency[32], (time of video 00:59) balancing power generation and supply or demand. The electricity being provided must always be kept at a specific frequency of 50 or 60 Hz and the permissible tolerance to its fluctuation is close to 0.050Hz[33].
Electricity has to be consumed the moment it is produced or else it is lost and black-outs occur. The frequency has to be maintained[34]. If the demand for electricity all of a sudden increases and its production doesn’t follow almost instantly, the electric frequency drops and there are problems, and vice versa. The frequency will increase if there is a drop in power consumption but the power production remains the same. The demand curve usually looks like a tall (big amplitude) Sinusoidal Wave (a horizontal repetitive S). During the day the power supply demand increases, creating the peak or crest and during the night when everyone is sleeping and businesses are closed the energy demand decreases creating a trough. The problem with the trough in power consumption is that so as not to overload the grid and burn it out the grid managers usually have to shut down a power plant or deactivate some wind turbines[35] (running time in video 4:42 to 5:44) which is a complicated and expensive thing to do. The ideal situation is when the amplitude in the demand curve is small meaning that the production of electricity is the same as the demand (consumption) of it.
This is where bidirectional charging comes in. Bidirectional charging, is when a plugged in or wirelessly charging car ceases to only draw power from the electrical grid and starts to have a more symbiotic relationship with it and cars give power back to the grid when it’s needed most.
During the night when the energy demand is low and the grid managers are trying to avoid shutting down a power plant or wind turbine which as already noted, is an expensive and difficult thing to do, electric vehicles, be it cars, buses or trucks could be charging and acting as an energy storage system or grid equalizer.
In the UK the power grid sometimes pays people[36] (time of video 16:00) to charge their EVs at night because it’s cheaper to do that than close down a wind turbine. Private cars which are also the majority of cars may be useful to their owner but they are a wasteful commodity. A person spends a lot of money to buy a machine which for most of 24 hours sits in a garage or parking facility. The UK plans to build huge batteries to store renewable energy[37] but there’s a much cheaper solution[38] During the substantial amount of time an EV sits idle it could be making money by selling a predetermined amount of power back to the grid when it was needed. The amount it sells back can be set by the EV owner taking into account their current travelling needs. The more EVs that are doing this, potentially hundreds of thousands to millions, the less energy per car or residential / grid battery packs “containers” that the grid would be using to keep the grid stable and running efficiently and without needing to shut down sources of power.
If more and more people install solar panels on the roofs of their homes, offices, businesses or factories and or have a wind turbine on their premises and use their cars or the ever cheaper house or domestic sized battery packs being developed, then the demand on the city grid will be reduced and the power grid will change from being the main or only source of power to being a supplementary source. Even more importantly with the grid becoming less centralized (dependent on the big traditional power plants or massive wind, solar farms) and more and more localized the need for very high powered power lines, which are environmentally unfriendly, will decrease.
Another new way of helping balance the electrical grid surplus or deficit was demonstrated by Lightsource BP[39], a developer and manager of solar energy projects. In November 2019[40] Lightsource stated that with a relatively inexpensive tweak to the inverters (the hardware that turns solar power into electricity) at one of their solar farms in East Sussex UK[41] they helped stabilize the grid through reactive power[42]. Reactive power is the ability to maintain voltage levels by reducing or increasing it on a grid[43]. This was achieved at the solar farm by its inverters.
As discussed in greater depth in the “Fully Charged Show”[44] at least 8 of the YouTube videos mentioned above, all lead back to Fastned’s or City of Dundee’s rapid charging station solution which is to use renewable energy to charge battery storage units like the Tesla ‘Powerpack’[45], the ESS Inc ‘EW’[46], the NEC Energy[47] and Ambri[48] ‘Liquid Metal Battery’ or RedFlow’s[49] ‘zinc-bromine flow batteries’ and then in tandem with the renewable energy and maybe a small contribution from the grid, it becomes possible to charge a number of EVs.
Urban electric pop up charging hubs, Ubitricity and its SmartCable, wireless inductive charging WiTricity, Electroad and Myenergi Zappi, Wallbox[50] are all or could be made bidirectional charging capable. Bidirectional charging is a possible future source for needed extra grid power.