Tag: electric vehicles (EVs)

Can electricity power heavy-duty vehicles?

3 January 2018

Electrification

On a blacked-out stage, a blast of white light appears. Smoke floods out, music blares and an excited crowd surges forward, smartphones held aloft. It’s a moment of rapture – but this is not a theatrical or musical performance. This is the launch of an electric car.

Specifically, the launch of Tesla’s new electric roadster – which claims to be the fastest production car ever made. And while the sportscar may have been the undoubted star of the event, it wasn’t the only one unveiled. Tesla also launched an electric-powered articulated lorry – the Semi.

With governments around the world setting ambitious plans to ban the sale of petrol-and-diesel-only cars, the introduction of electric-powered utility vehicles – like Tesla’s truck – in a range of industries will be essential to a truly decarbonised transport system.

Disrupting trucking

Tesla’s heavy goods vehicle (HGV) highlights the growing capabilities of electric vehicles (EVs) to deliver more than just short, urban journeys. It claims its Semi will be able to travel 500 miles on a single charge (enough to get you from London to Edinburgh comfortably) and tow 40 tonnes of cargo.

Tesla isn’t the only player with electric big rig concepts – Los Angeles-based Thor Trucks, Daimler and Volkswagen have unveiled their own – but its ambitious 2019 production target makes it a more immediate possibility than any other in the space.

Despite media coverage claiming the Semi’s mega-charging capability breaks the laws of physics, big business is taking a sunny view of Elon Musk’s latest innovation. Walmart, which has been taking strides to reduce its emissions, has already pre-ordered 15 of the Semis. Delivery firm UPS has used small electric trucks in major cities for some years already – it has placed the largest order so far, for 125.

Electrifying emergency response

In the world of emergency services, quick response is vital. EVs, then, which have fast acceleration and are quick off the mark, are ideal candidates to deliver – especially as battery technology becomes more reliable and durable.

Health services in Nottingham have already been trialling electric-powered fast response vehicles, while in Japan, Nissan has unveiled an all-electric ambulance that carries a lithium-ion auxiliary battery to power medical equipment on board.

This on-board power supply is a further advantage of EVs, and one not just restricted to emergency services. Electric pickup truck maker Havelaar, for example, offers power outlets on its Bison vehicle for electric tools.

The future of battery farming

Out in the countryside, EVs are making waves in farming. John Deere has unveiled plans for fully electric tractors, claiming they require less maintenance and have a longer lifecycle than combustion engines.

With more than a third of UK farms generating their own power from solar, wind and even anaerobic digestion using farm by-products, there’s potential for farmers to charge tractors renewably and cut their fuel and charging costs.

More than just helping cut emissions and costs, there can also be performance benefits. Given their acceleration abilities, electric tractors are well suited to heavy pulling without revving up engines and churning up ground.

Joining HGVs and tractors in their ability to apply almost instant torque to heavy industrial jobs are e-Dumper trucks. The Komatsu quarry truck weighs in at almost 45 tonnes and claims to be the biggest EV in the world.

The economic advantage of electrification

Air pollution and greenhouse gas emissions are the main driving force behind many anti-fossil fuel regulations. However, research suggests decarbonising transport systems also have economic advantages for businesses.

A report by financial services firm Hitachi Capital found that switching vans and heavy goods vehicles (HGVs) to electric or other alternative fuels could save British businesses as much as £14 billion a year.

It claims EVs run at 13p cheaper per mile than diesel-fuelled vans, while HGVs are reported to be 38p cheaper. That adds up to total savings of £13.7 billion a year if all Britain’s commercial vehicles were switched.

The move to a fully electrified transport system is already underway. The number of registered electric cars increased by 280% in the UK over the past four years, according to the Hitachi report. The Chinese city of Shenzhen’s entire fleet of 16,359 buses has gone electric – a transition that began in 2009 and has been assisted by an 80% drop in the cost of a lithium-ion battery pack. According to Bloomberg New Energy Finance, China’s need for electric bus batteries is almost on a par to that of all global EV battery demand. China could be said to be driving the market.

EVs are undoubtedly cleaner when it comes to road-side pollution. However, the exponential increase in EVs will only benefit the fight against man made climate change if countries’ entire energy systems continue to decarbonise. Emissions-free vehicles will need to be powered predominantly by low carbon electricity for a more electric future to be a sustainable one.

Every electricity storage technology you need to know about

24 November 2017

Power generation

The world is generating and using more renewable electricity than ever before, but in many cases it is being generated by intermittent – weather dependent – sources like solar and wind.

While these are imperative to a decarbonised future, they can’t generate power all the time, and this can cause gaps in electricity supply. One possible solution is storage. If we can store renewable electricity from intermittent sources when they are able to generate, it could then be utilised at times when they’re not.

However, the problem is the technology capable of storing electricity at a scale large enough to power a city doesn’t exist…yet.

The race to develop it is well under way, and several companies are working on building ever bigger, more efficient electricity storage methods. From pumping water up mountains to turning air into liquid, here are the emerging storage technologies (and some incumbent ones) shaping the storage landscape:

Pumped hydropower

What if we could power cities with something as simple as gravity? And a mountain.

Pumped hydropower storage uses excess electricity to pump water from a lower reservoir up to a higher one (for example up a mountain or hill) where it is stored. When electricity is needed, the water is released from the higher reservoir and runs down the natural incline, passing through a typical hydro-power turbine to generate electricity.

Pumped hydro is one of the largest-capacity forms of grid power storage and currently accounts for 99% of all bulk storage globally. The Bath County Pumped Storage Station in Virginia, USA is often referred to as the ‘world’s biggest battery’, and boasts a generation capacity of more than 3 gigawatts (GW), which is almost as much as the power output of Drax Power Station or Hinkley Point C.

So what’s the catch? While pumped-hydro storage is efficient and capable of holding huge capacity, its major drawback is it requires a suitable mountain or hill to be converted into a giant battery. Unsurprisingly, not every landscape offers one. Great Britain has limited potential – but has a number of pumped storage facilities including the impressive Dinorwig in the Snowdonia region of Wales, known as the Electric Mountain which, like Drax, doubles up as a tourist attraction.

In December 2018, Drax bought Cruachan Power Station, the second biggest pumped-hydro storage power station in Great Britain. Visit Cruachan — The Hollow Mountain.

Flywheels and supercapacitors

Some of the most-rapidly responding forms of energy storage, flywheel and supercapacitor storage can both discharge and recharge faster than most conventional forms of batteries.

The first works by spinning a rotor (or flywheel) to very high speeds using electrical energy. This process creates kinetic energy which is effectively stored within the spinning rotor until it’s required, at which point the kinetic energy is converted back into electricity.

Supercapacitors take a similar approach but store power electrically. With the combined properties of a battery and a capacitor, they store energy as a static charge, but unlike conventional batteries there is no chemical reaction during charging or discharging.

Lithium-ion batteries

Lithium-ion batteries are already the go-to power source for most home electronics thanks to their high-energy density and low self-discharge rates. But companies are looking to extend their usage by rapidly advancing the technology to take on bigger and better uses, most notably electric vehicles (EVs) and providing security of supply to national and regional electricity networks.

In South Australia, Tesla has just finished installing the world’s biggest lithium-ion battery facility. At 100 megawatts (MW), it will be able to supply 30,000 homes for an hour, such as when the wind drops and the turbines of the wind farm it is connected to are not producing much power.

Lithium-ion batteries are now the most widely used in EVs, but manufacturers are still facing the challenge of lowering the cost of their manufacture to a point at which to make EVs widely accessible.

Tesla has made achieving this a priority, establishing its massive ‘gigafactory’ in Nevada to help ramp up production and drop the batteries’ price. A true breakthrough on this point is yet to be reached, however.

Solid state batteries

The primary complaint for most domestic batteries today, be they in smartphones or EVs, is they just don’t last long enough. This is where solid-state batteries have a serious advantage.

Using solid electrodes and electrolytes rather than liquid electrolytes (used in most commercial batteries), solid-state models are smaller, cheaper and have a greater energy density than lithium-ion batteries. They can also be recharged much faster and emit less heat.

In an EV, this can lead to better efficiency, lower costs and safer operation. The only trouble is the technology isn’t quite viable at scale yet. Dyson and Toyota, are both putting serious money behind the technology and believe it will be on the market in 2020.

Hydrogen fuel cells

Hydrogen is one of the most-abundant elements on earth, so it’s an attractive fuel for any power-generation technology. The latest to emerge is hydrogen fuel cells, which are quickly growing in popularity in the automotive space.

The fuel cells work similarly to batteries with two electrodes separated by an electrolyte. However, rather than running down and needing recharging, hydrogen fuel cells can continue to produce electricity so long as a constant supply of hydrogen and an oxidizer are pumped through it.

This means a regular supply of hydrogen needs to be fed in to continue to generate power – prompting the rise of fuelling stations where hydrogen-powered cars can be ‘filled up’ with hydrogen when their batteries have run dry.

Beyond powering cars, hydrogen fuel cells have also been used to power buildings and NASA satellites.

Vehicle-to-grid systems

But what if beyond simply using electricity, EVs could themselves act as energy storage systems?

Between journeys, all cars spend long periods of time stationary. Vehicle-to-grid (V2G) systems can take advantage of this and give EVs the ability to discharge their stored electricity for distribution across the grid, helping meet demand during peak times. In effect, cars can become mini power plants.

Nissan and Italian energy provider Enel have already advanced plans for this sort of system and aim to install around one hundred ‘car-to-grid’ charging points across the UK. EVs plugged into these sites will be able to both charge their batteries and feed stored energy back to the National Grid when necessary. Drax, too, is involved in this space, funding research into V2G systems at Sheffield University.

Smart charging systems will help to automate this give-and-take of electricity further and allow EVs to further help reduce overall carbon emissions.

Compressed air energy

Compressed air energy storage works similarly to pumped hydropower, but instead of pushing water uphill, excess electricity is used to compress and store energy underground. When electricity is needed, the pressurised air is heated (which causes it to expand) and released, driving a turbine.

Behind pumped hydro-energy, compressed air is the second-largest form of energy storage, and is continuously being developed to become more efficient and less dependent on fossil fuels to heat air.

And similarly to pumped hydro, it’s a site-specific means of storage. Compressed air is normally best stored in existing geological formations, such as disused hard rock or old salt mines.

Lead-acid batteries

Their technology might be a century and a half old, but lead-acid batteries are still used today for the simple reason that they still work.

Many decades of development mean lead-acid batteries are cheap to produce and highly reliable compared to new innovations in the space. Today, they are most commonly used as car batteries, but they have also long served as off-grid storage for solar arrays.

Their drawbacks include the toxic nature of the chemicals involved and the short lifespan of 300 to 500 cycles. However, recycling programmes around these lead-acid batteries have been so effective that 99% of the batteries in the US were recycled between 2009 and 2013.

While more-efficient, longer lasting, faster charging and lighter batteries are in development, lead-acid models remain the cheap, tried-and-tested, standard for small-scale storage.

Redox flow batteries

Specifically focusing on renewable energy storage, flow batteries are significantly cheaper than lithium-ion grid-scale storage, and offer a longer lifecycle.

Flow batteries consist of two tanks of liquids that are pumped into a reactor where they generate a charge. The capacity of the storage facility is therefore determined by the size of the tanks holding their respective liquids, which can mean they are bulky and space intensive.

Compared to other grid-scale storage systems, however, flow batteries are more economical, suffer lower vulnerabilities, and could hold potential to store large amounts of energy for long periods of time – one of the reasons why Drax is funding a PhD in the area.

Liquid oxygen plant, tanks and heat exchange coils, the background a factory

Liquefied air

What more abundant resource to use for energy storage than the air around us? By cooling air down to -196^oC it is turned into a compressed liquid, which can be stored. When ambient air is exposed to this liquid it re-gasifies and expands in volume rapidly, rotating a turbine in the process.

One of the main advantages of this form of storage is its potentially high capacity – an impressive 700 litres of ambient air can be reduced to just one litre of liquid air. More than this, there is potential for it to become even more efficient by using waste heat and cold from industrial process such as thermal generation plants, steel milling, or the creation of liquefied natural gas (LNG).

UK company Highview Power Storage is currently trialling the technology at the Piliswoth landfill gas generation facility where it will provide energy storage as well as convert low-grade waste heat to power.

Want to find out more? Keep an eye on the Drax Repower project, which includes plans for up to 200 MW of storage. And Imperial College London’s Grantham Institute on Climate Change and the Environment produced this detailed infographic comparing the benefits and challenges faced by energy storage technologies.

How electric vehicles will impact global power demand

1 October 2017

Electrification

The future of cars is electric. Globally, governments are laying out plans to ban the sale of petrol and diesel-powered cars, while the falling prices of batteries will serve to make the vehicles more affordable to consumers and more profitable for manufacturers.

A recent report by Bloomberg increased its earlier 2016 forecast for electric vehicle (EV) adoption. It now estimates that by 2040, 54% of new car sales and 33% of the global car fleet will be electric.

This vision of the future points to considerably better air quality in urban and roadside environments across the world. But while EVs emit none of the tailpipe fumes of traditional fossil fuel-powered cars, there is still potential for associated emissions depending on how that electricity is generated.

For example, if the growing demand caused by EVs is met with fossil fuels, then ‘well-to-wheel’ emissions are still in play. However, as electricity grids decarbonise and become smarter and more efficient, EVs will become cleaner. Researchers at Imperial College London have shown that in the UK, year-round average emissions from EVs have fallen by half in the last four years thanks to cleaner electricity generation.

What this greater reliance on electricity for transport will certainly do, however, is massively drive up global power demand. Investment will be needed not only in electricity generation but also in smart technology that can allow the charging and, eventually, usage of EVs to be managed efficiently.

The growing demand of EVs

The Bloomberg report states global electricity consumption from EVs is expected to grow from just 6 TWh in 2016 to 1,800 TWh by 2040. While the figure represents a massive increase in the electricity required to power EVs, 1,800 TWh represents just 5% of the projected global power consumption in 2040. By comparison, the UK as a whole consumed just 304 TWh of electricity in 2016.

This clearly highlights the widespread need for global investment in electricity generation on the whole, beyond just what will be required to power EVs. However, the unique challenge EVs pose is less how they recharge but when they will recharge.

Smoothing spikes

Assuming supporting infrastructure and technology progress to enable widespread on-street and home charging, then the demand for electricity to charge EVs will mostly likely come in the evening. This could result in additional pressure being placed on energy generators and national grids due to mass EV charging.

Utilities and regulators will need to implement policies to encourage off-peak charging (for example overnight) and spread out the demand from EVs. One way these spikes will be managed is through ‘time-of-use’ rates to encourage drivers to charge their vehicles at off-peak times to avoid higher electricity bills. However, technological improvements will also help to manage the demand EVs place on energy systems.

Tech solutions

Smart charging tech is one of the most important aspects of this in allowing cities, utilities and consumers to automate vehicle charging at times when overall demand is lower. Storage technology will also play a key role in managing increasing demand on both consumer and operator ends.

Adoption of home power storage systems is expected to grow as fast as solar photovoltaic energy has in recent years, which will enable consumers with home solar arrays to store energy and charge vehicles at times to avoid peak-hour charges. On the supplier end, advancement in storage technology will allow generators to deliver electricity above their usual capacity and meet spikes in demand.

Autonomous vehicles

While the report suggests autonomous vehicles will not have a significant impact over the next decade, the longer-term influence of self-driving vehicles will have direct consequences on demand.

Autonomous cars will be able to drive in a way that is significantly more efficient than humans by driving closer together and interacting with the surrounding city to prevent congestion. With widespread adoption, this greater efficiency would mean cars would use less energy and require less time to recharge.

However, ownership of these types of vehicles will likely be shared, particularity in urban environments, resulting in fewer overall cars on the roads and, ultimately, plateauing or even declining demand from EVs in the 2040s and beyond.

Globally, investment is needed to meet and support the growth of EVs over the next two decades. Governments and businesses must begin to roll out charging infrastructure and clean energy solutions to meet future demand, as well as the smart city technology that will enable the mass adoption and eventual automation of EVs.

Do electric vehicles actually reduce carbon emissions?

19 August 2017

Electrification

Electric vehicles (EVs) are often seen as a key driver towards a greener future. Indeed, transport accounts for roughly a quarter of the UK’s greenhouse gas emissions and seriously affects air quality in major cities.

To tackle pollution problems, governments around the world are implementing ambitious policies to promote the electrification of transport and phase out ICE (internal combustion engine) vehicles. The UK and France both plan to ban the sale of petrol- and diesel-only cars by 2040 while India is setting an even more ambitious end date of 2030.

Added to this are EVs’ growing popularity with drivers. There are now almost 110,000 electric cars and vans on UK roads spurred on by lowering battery costs and a growing range of models. Including plug-in hybrid vehicles, EVs now account for 2% of new registrations.

Switching to EVs is an obvious way to massively cut pollution in areas of dense traffic. But the question remains – how clean are EVs on the broader scale, when you look at the electricity used to charge them?

Electric vehicles are getting cleaner

EVs don’t give off the same exhaust emissions as engines, but the power in their batteries has to come from somewhere. Follow the flow back from the car, through the charging point, all the way back to the power station and it’s likely some of that electricity is coming from fossil fuels. And that means emissions.

“They weren’t as green as you might think up until quite recently,” says Dr Iain Staffell, a researcher at Imperial College London and author of Electric Insights – a study commissioned by Drax that analyses electricity generation data in Britain. “Now, thanks to the rapid decarbonisation of electricity generation in the UK, EVs are delivering much better results,” he continues.

In fact, year-round average emissions from EVs have fallen by half in the last four years thanks to greener electricity generation. Today, they are twice as efficient as conventional cars.

Take the Tesla Model S. In the winter of 2012, producing the electricity for a full charge created 124g of carbon emissions per km driven, roughly the same as a 2L Range Rover Evoque. Now the carbon intensity of charging a Tesla has nearly halved to 74g/km in winter and 41 g/km in summer, as the UK continues to break its own renewable energy records. For smaller EVs, the results are even better. The Nissan Leaf and BMW i3 can now be charged for less than half the CO₂ of even the cleanest non-plug-in EV, the Toyota Prius Hybrid.

So, the current outlook for EVs is hugely positive – but as their numbers continue to increase, will the demand they add to the grid put their clean credentials at risk?

Will EVs accelerate electricity demand?

The National Grid suggests there could be as many as nine million EVs on UK roads by 2030, which could lead to an additional 4-10 GW of demand on the system at peak times. This, in some cases, could lead to a rise in emissions.

Electricity demand in Britain typically peaks between 6pm and 10pm, when people arrive home and switch on lights and appliances. If you were to charge your EV between those evening hours, the emissions would be 8% higher than reported in the chart above. If you charged between midnight and 6am, they would be 10% lower.

Today, this demand is met by the existing mix of power stations (which last quarter included more than 50% renewable and low-carbon sources). But when there are sudden spikes in demand above this typical usage, the National Grid must call in the help of carbon-intensive reserve generators, such as coal-powered stations. Polluting diesel generators are also on standby around the UK, ready to turn on and feed into regional distribution grids at a moment’s notice.

To meet the challenge of peak-time EV charging, less carbon intensive power generation, storage and smart power management systems are needed. These include rapid response gas power stations such as the four Drax OCGTs planned to come online in the early 2020s, as well as grid-scale batteries, home-based batteries and demand-side response schemes. As the share of intermittent renewable capacity on the grid increases, more back-up power needs to be available for when the wind doesn’t blow and the sun doesn’t shine.

Keeping our future fuels clean

A future increasingly relying on back-up generators is far from inevitable, especially if the use of smart technology and smart meters increases. By analysing electricity costs and country-wide demand, smart meters have the potential to ensure EVs only charge outside peak times (unless absolutely necessary), when electricity is more likely to come from renewable or low-carbon and cheaper sources.

If the grid continues to decarbonise through advances in renewable technologies and lower-cost coal-to-biomass conversions, the potential of EVs’ electricity coming with associated emissions is diminished even further.

There is no doubt that EVs will make up a significant part in the future of our mobility. That they will also play a part in the future of cleaning up that mobility is as good as assured, but on this journey, it’s imperative we keep our eyes on the road.

Commissioned by Drax, Electric Insights is produced independently by a team of academics from Imperial College London, led by Dr Iain Staffell and facilitated by the College’s consultancy company – Imperial Consultants.

Power and the rise of electric cars

12 December 2016

Electrification

Power supply for electric car charging. Electric car charging station. Close up of the power supply plugged into an electric car being charged.

All great technological innovations need infrastructure to match. The world didn’t change from candles to lightbulbs overnight – power stations had to be built, electricity cables rolled out, and buildings fitted with wiring. The same is true of electric vehicles (EV).

Think of the number of petrol stations lining the UK roads. If EVs continue their rise in popularity, the country will need electric car-charging facilities to augment and then replace these petrol stations.

This could mean big extensions of electricity grid infrastructure, both in the building of new power generation capacity to meet demand, and in the extension of the networks themselves.

In short, it could mean a significant change in how electricity is used and supplied.

The need for better electricity infrastructure

In 2013, only 3,500 of newly registered cars in the UK were plug-in electric or hybrid EVs. In 2016, that number jumped to 63,000. Their use is rising rapidly, but the lack of infrastructure has kept a cap on the number of EVs on UK roads. That is starting to change.

As of 2019, all new and refurbished houses in the EU will have to be fitted with an electric car charging point, according to a draft directive announced by Brussels. The UK will probably no longer be an EU member by the time the directive comes into effect, but nevertheless, the UK government is pursuing its own ways to account for the rise of EVs. It has pledged more than £600 million between 2015 and 2020 to support ultra-low-emission vehicles – £38 million of this has already been earmarked for public charging points.

There are more innovative responses to EV rise, too. Nissan, in partnership with Italian energy provider Enel, has announced it will install around one hundred ‘car-to-grid’ charging points across the UK. With their innovative V2G technology, cars plugged into these sites will be able to both charge their batteries and feed stored energy back to the National Grid when necessary. So when there is a peak in demand, the Grid could access the cars’ stored energy to help meet it.

The total capacity of the 18,000 Nissan electric vehicles currently operational on UK roads comes to around 180 MW. So even today – before electric vehicles have really taken off – this could give the National Grid an additional supply roughly the size of a small power station.

Peaks in electricity demand, however, tend to occur in the late afternoon or evening as it gets dark and more lighting and heating gets switched on. This also happens to be rush hour, so under this scheme the time of day the cars are most likely to be on the roads is also when it’d be most helpful to have them plugged in. This could lead to financial incentives for people to give up the flexibility of driving their cars only when they need to.

More electric cars, more demand for electricity, more pollution?

More EVs on the road makes sound environmental sense – they enable a 40% reduction in CO2 emissions – but ultimately the energy still has to come from somewhere. That means more power stations.

The scale of this new demand shouldn’t be underestimated: if European drivers were to go 80% electric, some studies have suggested it would require 150 GW of additional on-demand capacity – the equivalent of 40 Drax-sized power stations.

But if EVs are to live up to their green potential, that additional power needs to come from innovations in storage (such as in the Nissan example) and from renewable sources like wind, solar and biomass. Fossil fuels would ideally be used only to plug any gaps that intermittency creates – for example by briefly firing up the small gas power stations Drax plans to build in England and Wales.

What does this mean for generators?

Drax, as operator of the UK’s largest biomass power station and with plans for new, rapid response open cycle gas turbines (OCGTs), is well placed to be at the forefront of providing reliable, affordable power in the event of a widespread rollout of electric vehicles. The OCGTs in particular, are designed for use in peak times which, in the future, could be when the nation’s electric vehicles are plugged in overnight – today this is when electricity demand is at its lowest.

A future of more electric cars is a positive one. They’re cleaner, more efficient, and they are well suited to our increasingly urban lives. But now that we have the technology, we need to ensure we can deliver the lower-carbon infrastructure they need.

Tag: electric vehicles (EVs)