The changing face of electrification

SHAUN COOPER

The removal of diesel-powered trains from the national rail network by 2040 (2035 in Scotland) is key to achieving the UK Government’s net-zero-carbon target by 2050.

To meet its sector targets, the rail industry must continue to find sustainable and costefficient solutions. Electrification is one of the key drivers, along with hydrogen and battery train technology, which will enable a broad range of benefits to be realised: improving people’s health, creating better places to live and travel in, and driving clean economic growth. A changing market

Over the last decade, electricity distribution has undergone significant changes. Not only has there been a trend towards the decentralisation of power generation, but the use of renewable energy has also increased significantly. Renewables suppliers are now producing more than 20 per cent of the UK’s electricity, a share which is forecast to increase to 50 per cent by 2025.

Rail electrification has also seen some major changes, with benefits coming from both product and process innovation. One example of this is the use of static frequency converter (SFC) technology, which addresses the issue of phase imbalance. Whereas the UK electricity network operates on a three-phase balanced system, railway power supplies have traditionally been connected directly using just

two phases of the network. This causes a phase imbalance, restricting the amount of power that can be obtained from the network operator’s electrical supply. The issue is exacerbated by the shift to renewable power generation, which is less resilient to phase imbalance than coal-fired generation.

The use of static frequency convertors eliminates phase imbalance and provides more flexibility for supply to the railway, making connections to the network possible at various voltage levels, as well as supporting the shift to renewable energy supply.

Early contractor involvement

With an ever-growing demand for a greener, smarter, more reliable railway, the industry is also continually challenged to make the optimal use of the available investment. One approach that is increasingly being used to help meet this challenge is the adoption of early contractor involvement (ECI). By involving the technology supplier at an early stage, a much greater degree of operational flexibility can be achieved, and programme disruptions minimised. This means that potential risks and challenges can be identified and enables strategies to be developed to ensure that projects meet the requirements of their stakeholders.

For example, when engaged at the ECI stage, Siemens Mobility typically deploys its Sitras Sidytrac simulation software, together with calculations from its Sicat IT tools. This provides the programme team with key insights into the various system interactions and the power quality that is required, both to allow for voltage fluctuations and also to avoid operational disruptions. The software package allows for comprehensive studies of the electrical network to be undertaken, including electromagnetic capability (EMC) and power modelling.

By engaging the electrification team at the initial feasibility stage, system support can also be delivered consistently throughout the life of the project, so reducing overall costs and programme length. Through early involvement,

THE TECHNOLOGY EXPLAINED

Air-insulated switchgear

The Sitras ASG25 air-insulated switchgear for 25kV AC traction power supplies is suitable for use in single and two-phase AC traction power supply systems and is currently the only containerised air-insulated switchgear solution on the UK market.

Air-insulated switchgear removes the use of sulphur hexafluoride (SF6) gas insulation, and so eliminates the need for any special precautions to be taken during manufacturing, operation or recycling. The containerised unit is manufactured, assembled and tested off-site in the UK and then transported into position ready to be connected to the power distribution system. This means there is a reduction in carbon emissions (compared to transporting equipment from overseas), as well as supporting the creation of jobs and skills within the UK.

Static-frequency converters

Traction requires a single-phase 25kV AC supply, whereas the electricity supply from the grid is three-phase. Traditionally, the railway has taken power from two phases, creating a phase imbalance, an issue which SFCs eliminate by converting three-phase input into the single-phase traction current required.

Surge arresters

When 25kV catenary equipment is to be installed underneath bridges or tunnels, in the past the structure has had to be modified, removed or replaced to provide sufficient electrical clearance. Surge arresters work in circuit with the overhead line system to address this issue, enabling reduced electrical clearances to be applied, so that if over-voltages do occur (for example from a lightning strike), the surge arrester reduces the impact.

Siemens Mobility has demonstrated substantial project cost savings and has been able to bring forward large programmes by several years, supporting business cases and enabling projects to secure funding.

From the early stages of a project, it is also beneficial to look at the railway as a complete ‘end-to-end’ system, with a single supplier, taking a holistic view, able to design and deliver the most cost-effective and efficient solution. Conversely, when each individual discipline is procured separately, there is a risk that the solution becomes over-engineered, with each supplier focusing purely on its own, relatively narrow area.

By involving technology providers for the whole route, rather than small sections of it, ECI programmes enable the optimum solution to be developed and assessed. Early modelling at GRIP (Governance for Railway Investment Projects) stages 3 and 4 also enables the electrification design to be shaped to meet both the strategic and the business case objectives. GRIP 3 is the stage at which the preferred option is identified, with stage 4 covering its subsequent development.

As an example, on one project for which the client had initially considered an auto transformer solution, by looking at a ‘whole system’ design, an alternative technology was ultimately selected. This delivered cost savings of around 60 per cent and a reduction in the programme length of around two years.

The integration of the strategy and technology required to control and power trains can also be better identified at an early stage of a programme. Then, passenger flow, train location, power loading and efficient infrastructure placement can all be modelled to inform the electrification system design. This also allows new technologies to be considered that may have otherwise been passed over. For example, systems such as air insulated switchgear, static frequency convertors, efficient overhead line solutions and surge arrestors can all contribute to a more efficient traction solution and to an overall decarbonisation programme.

Not only can this approach help minimise the overall cost of delivery, but, if appropriate, it can also lead to the introduction of output-based specifications, which encourage technology providers to take a more holistic, whole-life approach.

Similarly, frameworks for traction decarbonisation can also include reward structures for efficiencies and collaboration – recognising the appropriate risk allocation between customer and contractors. Innovative commercial models could then be developed, for example to encourage technology providers to offer licensing or ‘paid on performance’ schemes.

Effective ECI

To benefit from ECI, it is important to define exactly what the outputs from this stage of the programme need to be. ECI should clearly add value to either cost or programme certainty, or both. The ECI process and period must also be managed effectively, ensuring sufficient time and effort is set aside to build the team and set common goals, so that all parties are aligned.

The make-up of the ECI team is also important. It should include people who are not only capable of challenging the norm, but also have a true understanding and a passion to achieve the overall programme goals. They must also be willing and empowered to make the best decisions. Similarly, when the client is fully engaged, a true ‘one team’ approach develops, with all members being open and transparent throughout.

To achieve the best output for the programme, the client needs to ensure the ECI process and its team are properly resourced and funded, and ideally are co-located, which will help build its success and encourage the establishment of strong relationships.

Edinburgh Tram approach

As supplier of the SCADA (supervisory control and data acquisition), telecommunications, electrification, signalling and road traffic systems to the first phase of the Edinburgh Tram programme, Siemens Mobility was brought in right at the start of the second phase of the programme to deliver a 2.9 mile extension to the original network.

Working closely with the client, to develop the technology solution and business case fully, ensured the programme was within the cost envelope, was achievable and that the relevant risks were carried by the client, the main contractor and the system subcontractor as appropriate.

Initial discussions began around two years before the planned start of the project, enabling the technological solutions to be agreed at an early stage. This in turn helped the appointed main contractor to fully understand the tender and gave the client confidence to start an ECI stage with them. As a result, any misunderstandings or queries were addressed in a collaborative way, building the trust required to establish the optimum cost and programme plan.

Shaun Cooper is managing director – electrification, Siemens Mobility.

Selling Electrification

In a recent interview, an influential government transport MP commented: “Arguably, we are investing in something (electrification) which is still dirty when we’ve got green hydrogen just around the corner.”

Similar comments were made by some members of the UK Parliament’s Transport Select Committee on 11 November, when one member suggested that electric traction could be the wrong technology just as diesel cars were 20 years ago. This resulted in a newspaper headline “Rush to electrify rail risks new diesel fiasco” – a particularly ironic statement as electrification is, in most cases, the only way to replace diesel rail traction.

Such comments are demonstrably wrong. Most UK rail carbon savings in recent years have come from the greening of the grid and the virtual abolition of coal-fired power stations. Furthermore, hydrogen rail traction has significant inherent limitations and can only be green if it is produced from electricity generated from zero-carbon sources.

Coal-fired power stations are now a thing of the past.

DAVID SHIRRES

Yet it would be wrong to blame politicians for such statements. In many cases, their views are a failure of the industry to clearly communicate the basics of rail traction to decision makers. Politicians have many issues to consider and should not have to study lengthy documents in the absence of a clear, brief explanation of what is required.

Such a clear statement was provided to the DfT in 2007, in the form of a three-page letter making the case for electrification signed by Adrian Shooter, chairman of the Association of Train Operating Companies, and Iain Coucher, Network Rail’s chief executive. This included these key points:

“We can immunise the railway from changing fuels by an electrification programme that puts these decisions elsewhere” and “Using ‘diesel’ trains as ‘mini-power-plants’ - to generate tractive power - is both inefficient and wasteful. It is not a particularly efficient way to convert fossil fuel into power. It is, surely, better to manage this at a power-station level. And this is even before one takes into account the fact that diesel trains consume significant amounts of energy to simply transport heavy engines and fuel around the network.”

The Shooter / Coucher letter was successful in achieving the approval of a substantial electrification programme. Unfortunately, in 2017, the unacceptable cost overruns of these programmes resulted in the then Minister of Transport, Chris Grayling, cancelling electrification schemes. He had lost faith in the industry’s ability to deliver electrification in a cost-effective manner and concluded that electrification must be the wrong technology.

Task force reports

The rail industry decarbonisation task force was set up in response to Rail Minister Jo Johnson’s call, in February 2018, for the industry to “provide a vision for how it will decarbonise”. However, it did not have a free hand. As RSSB report T1145 noted: “UK government has made clear its intention to decarbonise rail where possible and to use innovative solutions rather than relying on full electrification.”

Hence, task force members were expected to focus on alternative selfpowered traction rather than stressing the inherent benefits of electrification. Yet battery and hydrogen traction, which can store only a fraction of the energy of diesel traction, are only suitable for a small percentage of rail passenger traffic and are unsuitable for freight. Thus, if diesels are to be eliminated, the only alternative is a large-scale electrification programme.

Had the task force immediately reached this conclusion, this could have been counterproductive as it would not have followed UK government direction. Thus, when the task force produced its first decarbonisation report in January 2019, its executive summary stated “Other traction modes, such as hydrogen, bimode and hybrid trains should be actively encouraged as the best low-carbon options where extension of the electrified network is not feasible or will not be the most cost- and carbon-effective whole system solution.”

The final 68-page report by the task force was published Great Western electrification programme.

in July 2019. The front of this report states that decarbonisation can only be achieved with “a balanced and judicious mix” of electrification and hydrogen and battery traction. Yet, midway through this lengthy report, it comments that a large-scale electrification programme of 4,250 route kilometres may be required.

Both these reports stress the need to develop decarbonisation solutions for alternative traction through research and innovation. They also have a credible analysis of the capabilities of various traction types. However, the inherent limitations of hydrogen and battery traction, which make them unable to offer the high-powered traction required for most rail services, are not mentioned until midway through these lengthy reports. Thus, this did not provide the clear and concise explanation of the basics of rail traction that is needed if decision makers are to make informed decisions.

They also omitted some key issues, such as modal shift from road to rail, which could save road CO2e (Carbon

Dioxide equivalent) emissions equivalent to those from the entire rail network, and the efficiencies of the different types of traction. RSSB report T1145 shows these to be respectively 80, 65 and 25 per cent for electric, battery and hydrogen traction.

The final decarbonisation report was followed by the publication of Network Rail’s interim Traction

Decarbonisation Network Strategy (TDNS) in July. This provided a clear vision and rationale of what’s needed, following extensive consultation within the industry.

It highlights the benefits of electrification in respect of emissions reductions and other environmental benefits, modal shift from road to rail, passenger and freight users benefits, operational cost reductions and wider economic benefits.

These benefits, and a range of costs, were used to develop an interim business case for five different rates of delivery of the programme, which considered that decarbonisation of the unelectrified network required electrification of 13,040 single track kilometres (stk) and the deployment of hydrogen and battery trains on 1,300 and 800stk of infrastructure.

International rail comparisons

The particularly low rolling resistance of steel wheels on steel rail makes railways highly energy efficient, and thus one of the lowest-carbon modes of transport. Electrified railways that benefit from the unique ability of rail vehicles to use electricity straight from the grid offer further carbon savings. In the UK, they have benefited from the impressive reduction in carbon intensity of the national grid from 459 to 198 tonnes per GWh between 2005 and 2019.

Rail’s 2019 carbon credentials are shown in the latest figures (BEIS/Defra) for UK passenger travel emissions. For car (with only the driver), domestic flight, bus and rail these are, respectively, 171, 133, 104 and 25 grammes of CO2e per passenger kilometre. For freight, the respective figures for freight carried by HGV and rail are 136 and 27.5 grammes per tonne kilometre.

The task force reports rightly stress rail’s environmental credentials, but does not make carbon comparisons with other rail networks, as shown in charts 1 and 2. These use data in reports published by International Energy Authority (IEA). Unfortunately, this shows that, compared with other railways, Britain’s train fleet has a poor carbon footprint.

International Energy Agency (IEA) launched its 'Future of Rail' report in New Delhi in 2019. The report is downloadable on-line and a worthwhile read for anyone interested in international railway developments. It argues that investment, such as electrification, to encourage modal shift to rail offers significant benefits in respect of energy efficiency, reduced reliance on fossil fuels and a substantial cut in greenhouse emissions. 2015 railway carbon emissions are shown in the IEA's Railway Handbook 2017 whilst the proportion of diesel traction in each of these regions is shown on a chart on the IEA website.

The charts in this feature are derived from this IEA data with comparable UK data derived from ORR statistics that show 2016/17 traction energy consumption to be: electric traction (m kWh) - 3,523 passenger and 58 freight and diesel (millions litres) - 501 passenger and 168 freight. Conversion factors used were: 1 litre of diesel = 38 MJ and 1 kWh = 3.6 MJ.

The CO2e emissions shown in chart 1 are a reflection of both energy efficiency and train loading. As 70 per cent of UK passenger trains use relatively low-carbon electricity and, until Covid, were carrying large numbers of passengers, it might have been expected that they would have relatively low emissions. Yet, at 46 grams per passenger kilometre (gpk), their emissions are amongst the world’s worst. This compares with Europe’s 28gpk and is more than twice the world average of 18gpk.

Chart 2 shows that this poor record is due to the UK passenger train fleet getting a high proportion of primary energy from diesel fuel. As diesel trains have less than half the efficiency of electric trains, using large amounts of diesel results in a low overall average fleet energy efficiency and, consequently, a poor carbon footprint. Diesel trains are only 30 per cent of the UK fleet, yet diesel accounts for 58 per cent of its energy consumption. This is more than twice that of the rest of Europe’s passenger rail fleet, which gets only 25 per cent of its energy from diesel.

Deutsche Bahn ICE3 high-speed train approaches Utrecht.

Russian freight train hauled by a 9,200kW 3-unit 3ES5K Ermak locomotive.

At 27 grams per tonne kilometre (gtk), UK freight trains have a particularly poor carbon record. This compares with Europe’s 16gtk and the world average of 14gtk. Britain’s rail freight gets 96 per cent of its energy from diesel fuel. Whilst USA freight trains are entirely diesel powered, their CO2e emissions are only 18gtk as they are heavily loaded. Russian railways which also has heavy freight trains, has the world’s lowest freight emissions record of 9gtk as 64 per cent of their energy is from electric traction.

As the vision of the rail decarbonisation task force is “for the UK to have the world’s leading low-carbon railway by 2040”, the omission of such international comparisons is surprising. They show that this vision is not achievable, although the UK could rise up the rail decarbonisation league table with an extensive electrification programme.

Explaining electrification.

“Most businesses fail at marketing because they address their ‘what and how’ but ignore the ‘why’.” This quote from a marketing handbook seems particularly apt in the way that the rail industry has tried to sell electrification to decision makers. Although various reports state that electrification offers more powerful, efficient, greener trains, very little, if anything, explains why this is the case, with the exception of an appendix in Network Rail’s TDNS. What is needed is a simple, one-page document which makes the points shown in the explaining electrification box.

Selling electrification also requires a simple explanation of why electrification projects went so horribly wrong just a few years ago and what has been done to ensure such cost overruns will not reoccur. It is not surprising that the UK Government lost confidence in the industry’s ability to deliver electrification at that time. Hence, the industry needs to do all it can to regain its confidence and trust. Otherwise, decision makers may perceive electrification to be unaffordable or may not be prepared to accept the risk of cost overruns.

The Railway Industry Association’s excellent Electrification Cost Challenge report provides many answers, and much has been done to address its recommendations. This report also makes a strong argument for a rolling programme to reduce the cost of electrification. It is hoped that this, and the experience of more recent electrification projects being delivered to budget, should provide the necessary reassurance that the industry can deliver electrification in a cost-effective manner. Network Rail initiatives to reduce electrification costs, as reported in our accompanying feature “Routes to Zero Carbon Rail”, should provide further reassurance.

Electric trains are more powerful and efficient than self-powered trains for the reasons shown below. No amount of research and innovation can change the validity of these points which reflect the laws of science and space constraints. » Planes, ships, road vehicles and trains (except electric trains) must store energy on-board and need a power plant to convert the stored energy into kinetic energy to make them move. » A vehicle’s power and range are limited by the amount of energy it stores and the capacity of its power plant. The available space on a train limits the size of this plant. » The above restrictions do not apply to electric trains which can receive a large amount of energy whilst in motion. Thus they are unique in offering high-speed passenger and heavy freight transport. » Electric trains are highly efficient as taking electrical power from the grid to a train’s electric motors requires no energy conversion process. In addition, when it brakes, an electric train’s motors generate electricity and feed it back into the grid. » Hence a comparable electric vehicle has typically 50% more power than a diesel vehicle and requires only a third of the energy of a diesel train. » Electric trains are future proofed as they can be powered by whatever power source generates electricity.

They can also take advantage of significant carbon reductions in electricity generation. » If their electricity is generated by renewables or nuclear power they also have net-zero carbon emissions. » Alternative self-powered traction must store electricity, in batteries or use it to produce hydrogen.

These hold much less energy than diesel (batteries - 7% and hydrogen - 14% of diesel’s energy density). NOTE: It is considered that battery storage might be doubled by 2035. This would not detract from any of the above points.

However, concerns remain, as shown by a question asked at the Transport Select Committee in November, which showed that the industry’s ability to deliver cost-effective electrification is still a concern.

It is now just over three years since the then Secretary of State for Transport, Chris Grayling, cancelled the Midland main line and South Wales electrification due to cost overruns. His statement announcing the cancellation was entitled “Rail update: bi-mode technology.” This wrongly claimed that advancing technology had eliminated the need for electrification and did not mention carbon emissions.

Since then, much has been done to persuade decision makers of the need for electrification, and there are hopeful indications that the case may be accepted. For example Rail Minister, Chris Heaton-Harris told the Railways Industry Association annual conference that electrification sat “very nicely with the government’s green agenda” and that “electrification is going to have a massive part to play in that”. The government recently published its Ten Point Plan for a Green Industrial Revolution which commits to more railway electrification.

Nevertheless, it is clear that some decision makers still need to be convinced or do not understand what electrification has to offer. Although it is, of necessity, a lengthy document, Network Rail’s TDNS report addresses the misleading impression of the rail industry decarbonisation task force reports. Yet there remains a need for succinct clear messaging to explain that electric trains are intrinsically more efficient and powerful than other forms of rail traction and why no amount of research can fundamentally change this.

The Scottish example

One question asked at the November Transport Select Committee meeting was why Scotland had a different approach. Living in Scotland, I know the answer to this. Within Transport Scotland (the Scottish DfT), there are experienced railway professionals who know that Scotland’s railway can best serve the people of Scotland with electric trains that encourage modal shift, through improved journey times and better reliability, and that are also greener, more efficient, and cheaper to operate.

Hence, when the Edinburgh to Glasgow electrification programme had a substantial cost overun, the response was not to cancel electrification, but to ensure that lessons were learnt so that future schemes were delivered in a cost-effective manner. Transport Scotland officials have also been able to explain the benefits of electrification to Scottish Government Ministers to convince them that their scarce funds should be spent on largescale electrification of the Scottish rail network to enable it to achieve net zero carbon by 2035.

Network Rail’s TDNS study also promotes this UK industry vision of rail decarbonisation by a large-scale electrification programme. Given the political dimension, it was understandable the preceding industry decarbonisation reports did not directly promote such a vision, even though their content showed the need for electrification. That TDNS is now promoting the need for electrification is, no doubt, the result of useful conversations making the case for electrification. Thus, it was disturbing to hear rail decarbonisation task force leader Malcolm Brown promote an alternative vision to a recent Rail Technical Strategy event. In a keynote speech, which focused on innovations, he saw “a rolling continuous programme of introducing new technologies” and mentioned electrification only once. Despite TDNS showing that electrification is 85 per cent of the solution, he stated that there was no ‘silver bullet’. Furthermore, his comments that that there is no country leading the field in this area in which the UK had the potential to be a world leader are not supported by international comparisons. In contrast to this speech, TDNS and other evidence shows that there will be no further significant UK rail decarbonisation without large-scale electrification, which will also provide the high-performance traction needed to attract traffic modal shift and provide lower operating costs.

At this time, the UK government faces huge financial pressures with many calls on its purse strings. In such circumstances, it would be shocking if a decision not to invest in electrification was the result of misconceptions due to misleading messaging.

Note: As environmental performance is the number of passengers divided by emissions produced, this year’s empty trains will make the 2020 rail passenger carbon emissions much higher than last year's. Yet, rail remains an energy efficient form of transport which can take traffic from higher carbon road and air transport. Rail Engineer believes that a long-term view needs to be taken on action required to reduce global warming. Hence it is important to maintain and enhance rail capacity.