The future electricity grids would be more strong and efficient

The future electricity grids would be more strong and efficient

electricity grid

The energy sector is undergoing a deep transformation to respond to the need to combat climate change and thus contribute to the sustainability of life onour planet. This is being articulated through the so-called “Energy Transition”, which involves two big transformations in the electricity grid. On the one hand, traditional centralised generation is being replaced by an increasing number of distributed renewable generation plants located closer to the final consumer. In addition, the number of “self-consumers”, i.e. consumers capable of producing renewable energy, mainly photovoltaic, for their own use, is increasing. Secondly, we are witnessing a growth in the demand for electricity, with new needs such as electric vehicles and the air-conditioning of buildings.

All this results ingreater complexity of the electricity grid, especially the distribution grid, but also the transmision grid, because the flow of electricity is no longer unidirectional, but bidirectional. A more flexible management system is essential to make the transmission and distribution of electricity more efficient. Grid operators also need new technologies and tools to ensure a reliable and high quality service. These changes, which are already part of the present, are made possible by the evolution of traditional electricity grids towards smart grids.

The smart grid concept refers to a new feature of the electricity grid: in addition to transporting energy, it also transports data. To achieve this, digital technologies are needed to facilitate two-way communication between the user and the grid, IT and home automation tools to manage demand flexibility and distributed generation and storage resources, as well as the necessary technology and equipment capable of responding to volatile renewable generation.

One of the threats to guaranteeing an adequate and quality supply to the different players in the medium and low voltage network is faults. It is necessary to have the necessary means to locate them quicklly, givinig continuity of supply after a reconfiguration of the network, provided that this is useful to alleviate the effects of the fault, in the shortest possible time.

There are two indices for measuring the quality of supply in an electricity system: SAIDI (System Average Interruption Duration Index) and SAIFI (System Average Interruption Frequency Index). The SAIFI index takes into account the number of unavailabilities per user, while the SAIDI index takes into account the cumulative time of unavailability. These unavailabilities are generated as a result of various types of faults, the most frequent of which are earth and phase faults, the former being the most frequent.

When an earth fault occurs in a medium-voltage distribution network, the circuit breaker of one of the outlets of the high-voltage to medium-voltage transformer station shall trip by menas of the earth fault protection.

Subsequently, and in order to rule out that the fault is transient, the reclosing function shall operate, closing the circuit breaker. If the fault persists, tripping shall be repeated until the number of reclosings provided has been exhausted. If the fault is permanent, the affected part of the network will be out of service and it will be necessary to locate the fault and reconfigure the network in order to continue providing service to as many users as possible.

Traditionally, follwing the detection of a permanent fault by the telecontrol equipment, it is possible to carry out a remote reconfiguration operation from the control centre. This operation is carried out by an operator, following a defined protocol,and can take several minutes at best.

A modern, automated network will allow this protocol to be carried out without operator intervention, automatically between the telecontrol equipment. This network feature is known as self-healing, and allows the network to reconfigure itself autonomously in the event of a permanent fault, without the manual intervention of the control center. This significantly speeds up the time it takes to restore the power supply.

CARTIF has developed, within the framework of the INTERPRETER project (H2020, GA#864360), an assistance tool aimed at medium and low voltage grid operators. This tool, known as GCOSH-TOOL, helps to evaluate different scenarios by applying diferrent action protocols in the event of the appereance of one or more faults in the network. Its operation is based on proposing a seqeunce of optimisation problems with different constraints and objective functions, which allows the power to be delivered to each customer to be calculated, ensuring that the demand is met. To do this, a reconfiguration of the grid will be necessary to ensure electricity supply to the largest possible number of users in the scenario chosen by the operator based on technical and economic objectives.

The smart grids of the future will be more flexible and reliable than traditonal grids and will provide a higher quality of electricity supply to users. They will be connected in real time, receiving and providing information that will allow them to optimise their own electricity consumption and improve the operation of the overall system (active demand management). On the other hand, the trend towards distributed generation from renewable sources leads to a structure in the form of interconnected microgrids that will have the capacity to automatically reconfigure themselves in the event of any breakdown. The rapid evolution of technology is allowing these changes to take place very quickly, so that the so-called energy transition is becoming a reality, and we already have the infrastructure in place to reduce CO2 emissions, thus helping to curb climate change.

Boosting electromobility in Valladolid, with REMOURBAN project

Boosting electromobility in Valladolid, with REMOURBAN project

Urban mobility is paramount to address cities’ sustainable regeneration due to the number of issues that derive from a non-sustainable and non-efficient urban transport strategy. Urban transport represents almost a quarter of all the EU transport CO2 emissions. Conventional fuel vehicles contribute to the 40% of the city pollution, leading both to environmental damage and severe illnesses.

The challenge is to identify and analyze the best strategies to introduce clean technologies within an urban environment aligning with the city transport plans and policies and complying with the citizens’ needs.

Valladolid city has a strong commitment with sustainable transport and electromobility, as it is inferred from the list of measures  taken at city level and their participation in a number of smart city projects at national and European level.

One of the most remarkable ones is REMOURBAN (REgeneration MOdel for accelerating the smart URBAN transformation)  that is implementing a number of actions with the aim of boosting even more the penetration of electric mobility in Valladolid city.

Before REMOURBAN:

The largest share of public city transport in Valladolid is covered by the buses fleet, which  consists of 103 PLG fuelled, 46 biodiesel, and one hybrid (non plug-in)
Additionally, there are currently 466 taxis operating along the city. Among them, there are several hybrids (non plug-in) and others PLG fuelled. There are also two FEV, the first one operating since December 2011.

Mobility actions to be deployed within REMOURBAN project:

Though not fully deployed, most of the foreseen actions are already in progress.

  • Five plugged-in hybrid buses have been in operation for one year now. Two of them have been partially funded through REMOURBAN project.
  • Two FEV cars belonging to the City Hall private fleet are also providing service.
  • Additionally, a set of 45 fully electric vehicles (taxis, last mile delivery and other private business) are expected to arrive soon. To achieve this ambitious target, the City Hall has launched an interesting offer to boost the adoption of electric vehicles by these professionals. Interested parties will be able to apply as long as they commit to monitor the performance of their electric vehicles and related charging infrastructure. In return they will be getting as much as 8.350€ along 24 months.
  • Charging infrastructure has also been duly considered and the 34 slow charging points currently available all along the city will be soon upgraded and integrated in a remote management system to allow for seamless and reliable monitoring. Moreover, new charging infrastructure is being put in place to ensure fast charging to the buses and last mile delivery vehicles. In this sense, two pantographs (120kW) have also been installed at the beginning and end of bus line 7, and are currently being commissioned. They will provide the required electricity for their batteries so as to cover the inner area of the city in fully electric mode. The charging process should take around 8 minutes.
  • The freight delivery vehicles will profit from a fast charging station (50kW) that will also be installed in CENTROLID logistics hub. Last but not least, 4 additional charging points (22kW, Schuko, Mennekes) will be installed to provide charging to the taxis (not exclusively).

Monitoring actions:

A local ICT platform, in Valladolid, will be managed by CARTIF and further on will feed a global one for the whole project. Everything is being currently set up in order to get ready to register data, both from vehicles performance and from charging processes once the vehicles are in place. This is expected to happen by the beginning of year 2018 and will allow for two years monitoring (as requested by the EC).

On-board Units (provided and installed by GMV) will be registering a number of variables (speed, electric instantaneous engine consumption, battery level, instantaneous auxiliary systems consumption, GPS, emissions, etc.) that relate only to vehicle performance while on route. Additionally, data from charging processes will be collected by a charging manager. This will consist of initial and final charging time, as well as related charging energy.

Information from each monitored vehicle will come from both sources (driving route and charging process). The related set of data will be anonymized and processed by the local platform.

The final aim is to get valuable knowledge from electric vehicles performance in real conditions. All lessons learnt and experience gained will be transferred to other cities willing to adopt these technologies.

Would you buy an electric car?

Would you buy an electric car?

If you are hesitating about which technology would best fit your needs and liking, you should carefully analyze pros and cons and compare what you can get from both. A good starting point may be the type of driving you intend to do. If you plan to spend a lot of time in stop-start traffic, then the electric one might be the right choice.

For electric cars usually the high purchase price is a barrier that will only be overcome if you intend to drive enough kilometers along their useful life. You can counteract your initial investment with the lower price of electricity when compared to diesel or gasoline.

Another barrier is the driving range, which may be around 150 – 200 km under real conditions. Though this should be enough to cover actual everyday driving needs, facts show that this is an important deterrent for most potential buyers. Right now, plug-in cars account for not more than one-tenth of 1% of the global car market, and they are rare in the streets of our cities in most countries (Norway or Netherlands would be an exception). The Organization of the Petroleum Exporting Countries predicts just 1% of electric vehicles in 2040, while other experts don’t foresee a real impact for the next 50 years.

However, some hints suggest that predictions might be different for the short term. According to Bloomberg New Energy Finance (BNEF), several carmakers (including Tesla, Chevrolet and Nissan) plan to sell long-range electric cars at around €25.000, while they are investing billions on new models. Moreover, battery prices fell 35% last year and their related technology is quickly evolving towards higher energy density. According to BNEF the price of long-range electric vehicles is expected to fall below €20.000 by 2040 and 35% of new cars worldwide will be plug-in.

Real facts are that those vehicles achieving the highest number of sales in 2015 were Volkswagen Golf (275.848 sales), followed by Ford Fiesta (173.999 sales). These numbers have been surpassed by the 276.00 pre-orders received by Tesla for their new Tesla 3 model, though they won’t necessarily become actual sales in 2017. The basic Tesla 3 model will have a starting purchase price of €31.000, and a range of at least 346 km per charge. This makes a big difference to all we have seen till now. Tesla has been known worldwide for their luxurious models, only affordable for a few well-off and now they offer their technology to everyone.

So both price and driving range might not be barriers anymore.

Another argument in favour of electric cars is the driving experience, extremely quiet and smooth, with no need of a gearbox, and therefore easier than an internal combustion one.

Costs related to maintenance should be less in electric car than those from conventional ones, due to the absence of gearbox, oils and cooling fluids. Moreover, electric drives have less moving parts.

An important argument against might be battery longevity, which is not 100% reliable and might fail before expected. As this is somehow uncontrollable many manufacturers are offering long warranties to reassure potential customers. Some of them offer battery-leasing schemes as an alternative to acquiring the battery together with the car.

Finally, other obstacles for most potential buyers are the difficulties and additional costs associated with installing a charging point at home for an electric car, where one feels the vehicle will be safely charged at the preferred time (usually overnight).

You can get a pretty good estimation of the total costs associated to your new car, be it conventional or electric, with CEVNE, a tool developed by CARTIF that helps you decide from the budgetary point of view.

And if all the previous arguments are not enough to help you make a decision, you should then consider the benefits of electric vehicles for the environment. Tail-pipe emissions are zero, thus helping to improve air quality in our cities and towns, though we know the electricity used for charging must come from somewhere… maybe a coal fired power station. If this were the case we would not be contributing that much to a cleaner environment, though we know the share of renewable sources worldwide is steadily increasing.