2019 URBAN ENERGY REPORT BEYOND THE TIPPING POINT: …€¦ · In this Urban Insight report, Sweco experts debunk common misconcep-tions about some of the most promising energy storage

B E YO ND THE T IPPIN G PO I NT: FUTURE EN ERGY STO R AGE

2019UR B A N E NERGYR E PO RT

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URBAN INSIGHT 2019

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MARIA XYL IA

JULIA SVYRYDONOVA

S ARA ERIKSSON

ALEKS ANDER KORYTOWSKI

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WILL BATTERIESBE CONSIDEREDAN OLD TECHNOLOGYA HUNDRED YEARSFROM NOW? WHAT MIGHT THE FUTURESTORAGE CITY BELIKE?

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1 SUMMARY 4

2 THE STATE OF STORAGE – APPROACHING THE TIPPING POINT? 6

3 WHY ENERGY STORAGE? 10

4 LI-ION BATTERY STORAGE – ENERGY IN YOUR BACKYARD 16

4.1 WHERE ARE LI-ION BATTERIES USED? 18

4.2 WILL THE RESOURCES LAST? 20

4.3 TRENDS FOR BATTERY STORAGE 23

5 GEOTHERMAL STORAGE – ENERGY UNDER YOUR FEET 24

5.1 WHAT IS GEOTHERMAL STORAGE AND HOW DOES IT WORK? 26

5.2 WHAT DRIVES AND WHAT HINDERS GEOTHERMAL

STORAGE DEPLOYMENT? 28

5.3 TRENDS FOR GEOTHERMAL STORAGE 29

6 HYDROGEN STORAGE – ENERGY ON THE GO 30

6.1 HOW IS HYDROGEN PRODUCED? 33

6.2 A HYDROGEN ECONOMY? 34

6.3 TRENDS FOR HYDROGEN STORAGE 36

7 THE FUTURE CITY, A STORAGE CITY 38

8 BEYOND THE TIPPING POINT: CONCLUDING REMARKS 44

9 ABOUT THE AUTHORS 48

10 REFERENCES 50

CONTENTS

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FOR FOOTNOTES, SEE REFERENCES, PAGE 51.

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Behavioural and regulatory changes are needed to allow new technolo-gies to expand. Energy storage stands at the crossroads between the old and new energy landscape: it offers a unique opportunity for tailoring the energy system to urban needs in the decarbonisation era, bringing cost-effective solutions with minimal environmental impact while exploiting what digitalisation has to offer. Our urban insight comes down to the need to allow more flexibility in energy systems.

What is holding energy storage back? One factor is the costs, which have been high so far, but another issue is that humans are known for not always making purely rational decisions. Behavioural aspects affect per-ceptions, and new technologies are particularly sensitive to speculation and misconceptions. Should we wait for the perfect battery? Is it only possible to have geothermal storage in countries like Iceland? Is portable hydrogen storage too dangerous to ever consider? The answer to these questions is respectively no, no, and no.

The stakes are high: we need to battle climate change by reducing emissions through decarbonisation of power generation. We also need to reduce air pollution, which is a global problem threatening the health and livelihood of urban citizens.

1.SUMMARY

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“AS WE BECOME MORE AWARE OF THE TECHNOLOGIES SURROUNDING US AND THEIR IMPLICATIONS ON OUR LIVES AND OUR PLANET, MANY PEOPLE ARE EMBARKING ON A QUEST FOR MORE INFORMED CHOICES WHEN IT COMES TO URBAN ENERGY USE.”

In this Urban Insight report, Sweco experts debunk common misconcep-tions about some of the most promising energy storage technologies and imagine a future urban energy system. As our lives become more flexible, so do our energy needs. The demand for energy on the go, as well as the challenge of smoothly introducing renewable sources in the electricity grid, bring new energy carriers and storage solutions into the spotlight. Despite increasing deployment rates, the full potential of energy storage is far from realised.

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2.THE STATE OF STORAGE – APPROACHING THE TIPPING POINT?

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Will batteries be considered an old technology a hundred years from now? Will we sometime carry around our very own mobile hydrogen storing unit for covering our energy needs on the go? What would it take to make new energy carriers mainstream and how can urban energy systems transform and be transformed within the energy storage revolution?

In this Urban Insight report, Sweco addresses how storage technologies can solve the energy trilemma: delivering energy which is environmentally sustainable, with low costs and increased security of supply. We do this by debunking common misconceptions about a variety of energy storage technologies and offering a glimpse into what a future with energy storage may hold.

Storing energy is not new, but the way it is stored and what this can imply for future energy systems is undergoing such a transformation that the way energy production and consumption are linked and perceived may be forever transformed. Storing wood to burn for heating during the winter or building water reservoirs for hydropower plants are not considered innovative now, but these were innovations in their time.

Adoption of new technologies is driven by complex factors. Within our societies, there are people or groups of people more willing to adopt new technologies. Everett Rogers came up with the diffusion of innovations theory and the adoption curve in the 1960s (see ill. 1). According to this theory, the decisive point, the so-called tipping point, for expansion of a technology beyond the early adopters lies at a market share of between 15 and 18 per cent. In other words, if around 15 per cent of users adopt the technology, the innovation can be considered self-sustained and will further expand in the market. Where does energy storage stand in this context?

Ill. 1: The diffusion of innovation curve according to Rogers’s theory. Successive groups of consumers adopt a technology (black curve) until the technology’s market share reaches satura-tion level (yellow curve).

THE DIFFUSION OF INNOVATIONS CURVE

Innovators 2.5%

Early adopters

13.5%

Early majority

34%

the tipping point15–18%

Late majority

34%

Laggards 16%

Market share, %

0

100

50

25

75

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New energy storage technology and innovative energy carriers have experienced rapid growth in recent years. Global capacity for three of these technologies nearly doubled between 2012 and 2013, led by growth in thermal storage, followed by battery storage and hydrogen.1 Storage of electricity has nevertheless been increasing an average of 75 per cent annually since 2013. While most annual installed capacity was grid-scale up until 2017, this trend was reversed in 2018, when the largest share of installed capacity was attributable to behind-the-metre2 applications (see ill. 2). Excluding hydro, the second largest storage technology (by share of overall deployment) is Li-ion batteries. Is the future of battery storage behind-the-metre, i.e. at the household or community level?

The International Energy Agency (IEA) estimates that limiting global warming to below 2°C would require an increase in energy storage capacity from 140 gigawatts (GW) in 2014 to 450 GW in 2050.3 Despite the hype, only 3–4 per cent of electricity generated by utilities globally is currently stored.4 The energy world is on the verge of a storage revolution, but there is a risk that this transition will be hindered by a variety of barriers. Perhaps the main challenges to overcome are common misconceptions about the costs, safety and commercial availability of storage technologies.

“GETTING PAST THE MYTHS SURROUNDING NEW ENERGY STORAGE TECHNOLOGIES IS THE MISSION OF THIS REPORT.”

We discuss why energy storage should be an integral part of future energy systems, fol-lowed by a presentation of common myths, drivers and barriers regarding three storage technologies currently at the forefront of the transition: battery, thermal, and hydrogen storage.5 These three technologies are then integrated in a reflection on the storage city.

Ill. 2: Annual battery storage deployment per type of application. Source: IEA, 2019.

ANNUAL BATTERY STORAGE DEPLOYMENT

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0.5

1.5

2.0

2.5

3.0

3.5

GW

Grid-scaleBehind-the-meter

201820172016201520142013

Behind-the-metre Grid-scale Source: IEA, Energy storage: tracking clean energy progress.

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3.WHY ENERGY STORAGE?

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In order to meet the decarbonisation targets set in the 2015 Paris Agreement and limit global warming, fossil fuels in the energy system need to be substituted with fossil-free alternatives so that greenhouse gas emissions can be reduced. The role of electricity from renewable sources is particularly important in this context, especially as increasing electrification rates can be observed on a global scale. The heating and cooling sector is also of major importance. Figures for the EU show that in 2016 only 18 per cent of primary energy consumption in this sector came from renewable sources.6 Current observable trends include road transport electrification, storage of waste heat, and the use of tech-nologies (e.g. power-to-gas) with hydrogen use. Opportunities for increased local energy production that can be sustained by effective storage can also improve energy security and the resilience of supply systems.

The development of these trends will shape the role of energy storage in future energy systems. This role is pivotal for achieving a “flexible sector coupling”, i.e. the increased integration of energy end-use and supply sectors. Additionally, sector coupling can reduce the costs of decarbonisation.

The question is essentially how to optimally combine these different technologies in the future energy system. A first step is to understand time- and space-related constraints. As ill. 3 shows, the future of energy storage lies in the combination of technologies that can meet storage needs with short discharge rates plus technologies with longer dis-charge duration and higher capacity for longer-term demand. Smaller-scale systems will require high energy density and good longevity due to frequent discharging, while larger-scale systems require economies of scale for cost-effectiveness.

ENERGY STORAGE CAPACITY VS. DISCHARGE DURATION

minute hour day week season

discharge duration

Capacity

BATTERIES

GEOTHERMAL

HYDROGEN

Ill. 3: Mapping energy storage technologies in relation to capacity and discharge duration.

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Therefore, different energy storage technologies are selected based on power capacity and energy storage duration. This is related to energy and power density requirements as well as system requirements (amount of time energy needs to be stored, type of service provided, etc.). Cost-effectiveness is another component of the equation for selecting storage technologies (see ill. 4). Costs are the main factor hindering deployment. This may be associated with the cost of investing in the actual technologies (e.g. batteries, heat pumps, hydrogen storage tanks), as well as accompanying investments required for necessary infrastructure expansion to handle these new technologies (e.g. new electricity lines, gas pipelines, fueling stations, borehole systems).

We need Li-Ion batteries for our phones, as well as for our grids. However, we should not expect Li-Ion batteries to be the only solution for balancing the electricity grid, as this would not be technically and economically feasible. But Li-Ion batteries can coexist with other technologies, such as flow or sodium batteries or supercapacitors, which are cheaper but less energy dense and which store energy over longer periods. Bottled hydrogen can be used for portable storage, and hydrogen can store electricity produced in renewable power plants outside our city limits. Thermal storage can help recover energy to heat our homes, and phase-change materials can be used to heat winter clothing. Table 1 illustrates the main challenges that storage can help solve in various sectors.

FACTORS TO CONSIDER WHEN SELECTING ENERGY STORAGE TECHNOLOGIES

Ill. 4: Factors that should be considered when optimising the selection of energy storage technologies.

ENERGY DENSITY

STORAGE DURATION

POWER DENSITY

COSTS

How much energy can be stored per mass unit?

How long should energy be stored?

How fast can energy be released?

How much does it cost in relation to

other options?

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ELEC

TRIC

ITY

HEA

TTR

ANSP

ORT

Source: Eurostat, 2019

Source: EEA, republished by Eurostat, 2019

Source: Eurostat, 2019

Ill. 5: GROSS ELECTRICITY GENERATION FROM RENEWABLE ENERGY, EU-28, 1990–2016

Ill. 6: ENERGY CONSUMPTION IN EU HOUSEHOLDS, 2017

Ill. 7: GREENHOUSE GAS EMISSIONS BY IPCC SOURCE SECTOR, EU-28, 2016

Space heating, 64.1% Water heating, 14.8% Lighting and appliances, 14.4% Cooking, 5.6% Space cooling, 0.3% Other, 0.9%

Transport (including international aviation), 24.3% Fuels – fugitive emissions, 1.9% Other, 21.3% Energy industries, 26.9% Manufacturing industries and construction, 10.7% Households, commerce, institutions, and others, 14.9% Fuel combustion, 76.3%

Table 1: One chart per sector: how can storage technologies help address energy challenges within the EU?

0

20,000

40,000

60,000

80,000Thousand tonnes oil equivalent (toe)

Other

Municipal waste (renewable)

Biogases

Solid biofuels excluding charcoal

Solar photovoltaic

Wind

Hydro (excluding pumped hydro)

20162014201220102008200620042002200019981996199419921990

Hydro (excluding pumped hydro) Wind Solar photovoltaic Solid biofuels excluding charcoal

Biogases Municipal waste

(renewable) Other

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WHAT IS THE CHALLENGE? WHAT CAN WE DO?

Deploying battery and hydrogen storage could balance supply and demand of renewable energy. This would facilitate further introduction of renewables in the electricity mix, and, as a result, fewer emissions from electricity production.

Increasing the use of renewables and improving energy security can be drivers for implementing geothermal storage for addressing heating and cooling needs. Using geothermal energy would reduce heating costs for households in the long term.

Curbing the dominance of fossil fuels in road transport and reducing emissions requires a switch to zero-emission vehicles (e.g. battery electric and fuel cell vehicles). This would improve air quality in cities, reduce noise, and decrease depend-ence on fuel imports.

• Wind and solar represented 43 per cent of renewable electric-ity generated in 2016 in the EU.

• Production of solar energy is highest at mid-day and wind peaks at night, while our energy consumption peaks during mornings and evenings. This forms a duck-shaped curve between supply and demand.

• 60 per cent of EU household energy consumption in 2017 was for heating and cooling.

• Natural gas accounted for 36 per cent of the EU’s final energy consumption in households.7

• 80 per cent of European gas demand and 90 per cent of gas imports are for heating and cool-ing needs.8

• Transport sector emissions in 2016 accounted for nearly 25 per cent of the EU’s greenhouse gas emissions.

• 72 per cent of transport emissions came from road transport.9

• The share of energy from renew able sources used in transport activities reached 7.6 per cent in 2017.10

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4.LI-ION BATTERY STORAGE – ENERGY IN YOUR BACKYARD

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Lithium-ion (Li-ion) batteries are a family of rechargeable batteries with high energy density and good safety characteristics. For these reasons they are used in a wide range of applications, from portable batteries for electronics (phones, laptops) to large-scale utility-scale storage. It is important to note that, depending on battery type, various minerals are used, such as cobalt, nickel and manganese combined.

BOX 1: LI-ION BATTERY MYTHS

BATTERIES ARE “DIRTIER” THAN FOSSIL FUELSComparing the environmental impact of batteries and fossil fuels is like compar-ing apples and oranges: it doesn’t mean anything. This is because a battery is not an energy carrier itself – it is a means of storing an energy carrier, electricity in this case. A battery should be viewed as an “enabler” for fossil-free flexible energy: storing electricity from renewable sources in batteries can achieve major emissions reductions.

BATTERIES WILL NEVER STORE ENERGY AS EFFICIENTLY AS TRADITIONAL ENERGY CARRIERSThe energy density of current Li-ion batteries is about 10 times lower than petrol. But future battery technologies, such as Li-air batteries, have the potential to achieve energy density equal to that of petrol. So batteries may well achieve energy density comparable to that of other energy carriers. But this might not be the relevant question to ask. Is the energy density of batteries what matters most? As previously discussed, other factors might be more revelant: power density, or flexibility, as well as opportunities to use local energy to charge the batteries.

JUST WAIT A BIT – THE “UNICORN” BATTERY IS COMING SOON The unicorn, the saviour, the wonder battery. Unbeatable performance, high energy density, low costs and environmental impact, longer lifetime. And we might be lucky enough to see these batteries in markets sometime in the future, but just not as soon as the news reports say. A battery being developed right now in a lab will take at least 10 years to become commercially available. The battery needs to be tested rigorously to ensure operational safety, and then comes the challenge of achieving economies of scale. Most new battery technologies might never get past this threshold. Don’t wait for the unicorn battery, start now!

4.1 WHERE ARE LI-ION BATTERIES USED?

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“SO HOW CAN BATTERIES BE USED FOR ENERGY STORAGE? IN MANY CASES WHERE CONNECTION TO THE GRID IS COSTLY, DECENTRALISED, SMALL-SCALE SOLUTIONS FOR ENERGY STORAGE ARE THE WAY TO GO.”

DEMAND-CHARGE MANAGEMENTIn addition to paying for energy consumption, customers also pay for their consumption of power. These so-called power demand charges can be quite high if energy is used at peak times (i.e. when many customers require power from the grid). Using stored energy during peak hours could significantly reduce energy costs.

BALANCING THE VARIABILITY OF RENEWABLE ENERGY PRODUCTIONBattery storage could regulate wind and solar power transmission. Both sources are notorious for their variability; simply put, energy storage can save the day when the sun doesn’t shine or the wind doesn’t blow, by feeding stored energy from sunnier or windier days to the grid.

SMALL-SCALE STORAGEWhen used at the individual household level, battery storage can be the key to higher degrees of energy independence and lower energy costs. The concept of energy poverty is well known, with many households throughout the world facing electricity bills that require a large share of their income or present challenges in connecting to the grid. Sustainable Development Goal (SDG) 7 refers to securing energy access for all people in the world. In many cases where connection to the grid is costly, decentralised, small-scale solutions for energy storage are the way to go.

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Global battery factory capacity was 297 gigawatt hours (GWh) in early 2019, equivalent to the annual charging needs of nearly 150 million smartphones.11 China holds 202 GWh of the global capacity – a staggering 70 per cent of global factory capacity. Capacity is expected to increase by more than 200 per cent by 2023.12 One of the most hotly debated issues surrounding batteries is the role of resource availability and costs for their produc-tion. Ill. 4 summarises the situation for the main materials used in battery production.

BOX 2: HISTORY OF THE BATTERY

Although Benjamin Franklin first coined the term “battery” in 1798, it was Alessandro Volta who developed the first electrochemical cell in Italy in 1800. Various battery chemistries were invented later in the 19th and early 20th centu-ries, but the majority of these did not become commercial until the mid-20th century. The first rechargeable battery was the lead acid battery, invented in 1859 and still used to start most internal combustion engine cars. The first attempts to develop lithium batteries were made in the 1910s, but it took 70 years until lithium- ion batteries were invented by John Goodenough in the US. Wider commercialisa-tion of Li-ion batteries that are used today in portable devices happened during the 1990s but even now these are still not considered a fully mature technology, although they are commercial.13 The history of the battery shows that the road between invention of new chemistries to commercialisation is not paved with roses and long development cycles are required to ensure good performance, low costs and high safety levels.

4.2 WILL THE RESOURCES LAST?

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GRAPHITE

GRAPHITE

GRAPHITE

GRAPHITE

GRAPHITE

Ill. 8: Key materials used for Li-ion battery production, 2018.14

China, 68% Brazil, 10% Canada, 4% Other, 18%

Congo, 66% Other, 34%

Australia, 60% Chile, 19% China, 9% Argentina, 7% Other, 5%

South Africa, 30% Australia, 17% Gabon, 13% China, 10% Brazil, 7% Other, 23%

Indonesia, 24% Philippines, 15% New Caledonia, 9% Russia, 9% Australia, 7% Canada, 7% China, 5% Other, 24%

GRAPHITE

COBALT

LITHIUM

MANGANESE

NICKEL

China accounts the largest share (almost 70 per cent) of graphite mining. At current mine production levels, graphite reserves will last 323 years.

Political instability and working conditions in Congo have been a major concern. At current mine production levels, proven cobalt reserves will last 49 years.

The “lithium triangle” of Bolivia, Chile and Argentina plays a major role in the market. At current mine production levels, known lithium reserves will last 165 years.

Almost 80 per cent of manganese is mined in only 4 countries. At current mine production levels, manganese reserves will last 42 years.

Nickel has a more balanced market due to multiple producer countries. At current mine production levels, nickel reserves will last 39 years.

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BOX 3: URBAN MINING – ELECTRIC CARS POWERED BY RECYCLED PHONE BATTERIES

Could your messy drawer situation be the solution to transport electrification? The old phone still lying there has value. Lithium-cobalt (LCO) batteries are normally the ones used in mobile phones, and these batteries have 60 per cent cobalt content.17 An average smartphone has 10–20 grams of cobalt.18 In 2019, 5.13 billion mobile devices existed (66 per cent of the global population has a mobile device).19 It can be assumed that around 154,000 tonnes of cobalt can be found in the batteries of all these devices. It is estimated that a Tesla car battery currently contains an estimated ≈ 5 kilograms (kg) of cobalt.20

“IF THE CURRENT MOBILE DEVICE BATTERY STOCK WAS RECYCLED AT ITS END-OF-LIFE, ALMOST 31 MILLION ELECTRIC CARS COULD HAVE BATTERIES WITH MOBILE PHONE-RECYCLED COBALT.”

This is about 6 times the current size of the global electric car stock (5.1 million electric cars worldwide in 201821). Now imagine how many electric car batteries your old laptop can supply.

So how long will the proven reserves last? That depends quite a lot on the future increase of production volumes, but an estimation based on current production volumes shows that proven reserves of some materials will not last much more than one genera-tion. Of course, reserves15 and resources16 are not the same thing; resources in the Earth’s crust for some materials can last many years. The path of a resource to becoming a proven reserve is a long and costly one, however. The challenges can be addressed by either diversifying supply by further exploiting the reserves across more countries or by develop-ing new battery chemistries with alternative materials that are more abundant. More focus should also be directed towards battery recycling. There is a common misconcep-tion that effective recycling of Li-ion batteries is not technically possible. This is not true, and the lower recycling rates for some materials are directly related to the economic incen-tives to recycle them (see Box 3 for an example of the potential of urban mining).

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BOX 4: BATTERY STORAGE IN THE NEWS

SAND BATTERY TRIPLES BATTERY LIFEUsing sand (silicon) instead of graphite for the battery anode, this type of battery can achieve 3 times better performance, according to the company developing the solution.23

SOLID-STATE LITHIUM-ION BATTERIES FOR FASTER AND SAFER CHARGING In solid-state batteries the liquid electrolyte is replaced by a solid one, leading to superior performance, improved safety and faster charging times.24 Managing to commercialise solid-state batteries will be a breakthrough for electro-mobility, but there are still many challenges to overcome.

FOLDABLE BATTERIES FOR WEARABLES A South Korea-based company has developed a waterproof battery that is as thin as a sheet of paper.25 A foldable battery could be used in a variety of applications: mobile phones, fitness bands, GPS trackers, etc.

USING SALT TO DECREASE BATTERY COSTSSodium (i.e. salt, one of the most common elements on the planet) could replace rare-earth materials (e.g. cobalt, nickel, lithium) and significantly reduce the price of batteries.26

BATTERIES WITH BUILT-IN FIRE EXTINGUISHERTo reduce current safety risks associated with batteries, researchers have been testing batteries that include materials that can prevent fires in battery cells. This is done by adding a flame-retardant component called triphenyl phosphate.27

The quest for the unicorn battery is one of relentless optimisation for finding the optimal combination of traits: energy density, longevity, cost, safety. Unlike microprocessors, batteries do not follow Moore’s law,22 but their energy density is nevertheless continuously increasing. However, there are theoretical limits to current battery chemistries. The trend of decreasing costs of battery storage will most likely continue and only make battery deployment more attractive in the future (see ill. 9). However, the Li-ion battery’s short-comings, such as its relatively short lifespan and social and geopolitical concerns related to material mining, create a growing space for innovation in the quest for new battery chemistries.

4.3 TRENDS FOR BATTERY STORAGE

Ill. 9: Cost develop-ment estimations for Li-ion batteries through 2040. Sweco analysis on behalf of Stockholm’s Transport Administration.

COST DEVELOPMENT ESTIMATIONS FOR LI-ION BATTERIES

0

400

300

100

200

600

500

800

700

900

1,100

1,000

USD/kWh

204520402035203020252020201520102005

Nykvist & NilssonBloomberg New Energy FinanceRocky Mountain Institute

Rocky Mountain Institute Bloomberg New Energy Finance Nykvist & Nilsson

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5.GEOTHERMAL STORAGE – ENERGY UNDER YOUR FEET

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Do you ever think about the cooling of your home as throwing away excess heat in the garbage bin? What if, rather than throwing it away, you could store it and use it later when you have the need? There are different ways of storing thermal energy, i.e. heat and cooling. Here, the focus is on ways of storing thermal energy in the ground – so-called underground thermal energy storage systems, also known as shallow geo-thermal energy systems.

So how does geothermal storage work? Imagine it’s a summer evening and you are sitting on a rock by the sea. It’s getting chilly outside, but the rock is still warm. This is because rock and ground materials in general are materials that are good for storing heat. The energy in the ground is stored in the solid material and the naturally occurring ground water. Geothermal storage provides seasonal storage of excess heat and cool-ing, using a free and renewable energy source available everywhere. It is a local system that creates opportunities for autonomous energy supply. The most common system types used for geothermal storage include boreholes in rock and groundwater wells in aquifers. The system used depends on geological conditions (see ill. 10).

“UNDERGROUND STORAGE CAN HELP REDUCE ENERGY PURCHASES BY 70 PER CENT. THE NETHERLANDS PLANS TO INCREASE THE SHARE OF HEAT DEMAND SUPPLIED FROM GEOTHERMAL ENERGY BY 23 PER CENT BY 2050.”

The largest borehole system in Sweden has 203 boreholes to a depth of 240 metres (equivalent to 20 city buses placed in a row) and helps reduce energy purchases by 70 per cent.29 The most representative country in Europe for aquifer use is the Nether-lands, with 2,400 systems currently in use. The country plans to increase the share of heat demand supplied from geothermal energy from 0.3 per cent in 2018 to 23 per cent by 2050.30

Ill. 10: Geothermal storage systems: boreholes (left) and aquifers (right).28

5.1 WHAT IS GEOTHERMAL STORAGE AND HOW DOES IT WORK?

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BOX 5: GEOTHERMAL STORAGE MYTHS

GEOTHERMAL ENERGY? YES, I KNOW ABOUT IT – WHAT THEY HAVE IN ICELAND When talking about geothermal energy, most people think about hot geysers in Iceland. However, there are two basic types of geothermal energy. One is deep geothermal, coming from the Earth’s core, and the other is shallow geothermal, the solar energy stored in the ground. Deep geothermal energy utilisation usually involves drilling very deep boreholes near natural cracks, while shallow geother-mal energy (typically around 0–300 metres below the surface) is available everywhere.

BUT HOW CAN YOU HEAT SOMETHING WITH SHALLOW GEOTHERMAL ENERGY? IT IS SO COLD. The temperature of the ground is indeed not that high. From a fairly shallow depth, 15 metres, the temperature in the ground is more or less constant over the year and equals the annual average air temperature. Thus, the ground temperature in Berlin is 9°C, in Stockholm 6.6°C, and in Helsinki 5.6°C – temperatures that are not high enough to be used to directly heat a building. However, this temperature is much higher than the air outside in winter and can therefore be used for pre- heating. Another way to use geothermal energy is with the help of heat pumps that increases the temperatures to levels that are useful for heating and hot water production.

USAGE OF GEOTHERMAL ENERGY MAKES OUR CITIES LOOK LIKE SWISS CHEESEUsing geothermal energy in most cases requires drilling boreholes or water wells. Where geothermal energy systems are widespread, the question some-times arises as to whether the underground of our cities will look like Swiss cheese. Our cities already have lots of communications and service tunnels underground: metro, car tunnels, tunnels for district heating and cooling pipes, telecommunication, sewage and so on. Using the example of Stockholm, the city has around 60,000 boreholes for geothermal energy use. That may sound like a lot, but we estimate that all the boreholes can fit in the penalty areas of just one football field. By volume, they correspond to about 1.5 per cent of all under-ground construction in Stockholm.

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Thermal energy storage in the ground provides many opportunities both in and outside cities. These applications exist today – you might have come across them without real-ising it.

SEASONAL STORAGE FOR BUILDINGSStorage can be used for buildings that have both heating and cooling demands – such as offices, shopping centres, hospitals and airports. Storing your own waste heat and cooling for later use in the season when it is needed can save primary energy and as well as money.

CONNECTING CITY DISTRICTSGeothermal energy systems need not be limited to a single building. In a group of build-ings (city districts, sports centres, etc.) one user may have a heating need at the same time as another produces surplus heat. Exchange of energy is enabled with a thermal grid. By adding geothermal storage to the grid, surplus energy can be stored seasonally. Waste heat from industry, data servers, etc. can also be stored. This is similar to a dis-trict heating network, but at the local level.

ROADS, BRIDGES AND TUNNELSCertain infrastructure can be susceptible to freezing in winter. This may be the case for pavements, bridges and sloping roads, train platforms and airport runways. By installing heat exchangers (tubes filled with an energy carrier) under the road section and con-necting them to boreholes, this solar energy is stored in the ground and then used for heating in winter. Another interesting possibility is to use geothermal storage to cool subway or train tunnels.

BOX 6: HISTORY OF GEOTHERMAL STORAGE

A Swiss patent for extracting ground heat via a heat pump appeared in 1912. However, it was not until World War II required energy rationing that ground source heat pump (GSHP) technology was actually installed and developed in the northern US. The surge of interest faded in the 1950s and 60s due to low oil prices but was reignited in Northern Europe following the 1973 oil crisis. Research in the 1980s and 90s further developed the field and the International Energy Agency took great interest. More countries caught on, and there are currently more than 2 million systems in the world.31

Although the initial investment cost for geothermal energy systems is typically high, a large part of the energy used is free from the ground. This generally leads to lower energy bills. There is virtually no European country where underground storage or ground source heat pumps do not exist. But there are differences in how prevalent the technology is, depending on factors such as energy prices, regulatory frameworks and public knowledge.32 Lack of knowledge about the technology, or the perception that it is difficult to build and operate, may deter investors from even considering making the investment. For example, if natural gas (which people are familiar with) is cheap, there will be less incentive to invest in a thermal energy storage system – even though gas produces more emissions. But with the wide variety of types and applications of under-ground thermal storage systems, there is definitely potential everywhere.

5.2 WHAT DRIVES AND WHAT HINDERS GEOTHERMAL STORAGE DEPLOYMENT?

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BOX 7: GEOTHERMAL STORAGE IN THE NEWS

STORING 100°C EXCESS HEAT FROM HEAT POWER PLANT IN THE GROUND FOR USE IN WINTERIn an ongoing development project in Helsingborg, Sweden, the energy utility company Öresundskraft is working with Sweco to explore options for storing excess heat from a combined heat and power (CHP) plant in summer and supply-ing the stored heat to the city’s district heating grid in winter. If completed, the system will be able to store 50 GWh capable of heating approximately 2,500 single-family houses all year round.33

EFFICIENT SUMMER COOLING THROUGH SNOW STORAGE AT THE OSLO AIRPORT During the winter around 100,000 cubic metres of clean snow is collected, cov-ered with insulated sawdust and stored until the summer season. During summer, when there is a cooling demand, cold water from melted snow is used to cool the airport buildings.34

SWEDEN’S LARGEST ACCUMULATOR TANK IN THE CAVERNOld oil caverns built in the late 1970s have been converted into large-scale seasonal storage in the Hudiksvall district heating network. The caverns are each as tall as a 10-storey building (25 metres) and as long as two football fields (200 metres). The energy company benefits from the storage by increasing its production of renewable electricity and having capacity to supply the entire town of Hudiksvall with district heating from the caverns for one full month in the summer.35

“TODAY’S PRAXIS OF NOT USING SEASONAL STORAGE FOR HEATING AND COOLING IS LIKE THROWING THESE RESOURCES IN THE BIN ONE SEASON AND PAYING FOR THEM THE NEXT.”

A future with geothermal storage, and utilisation of the renewable solar energy stored in the ground everywhere, is fully possible and has major growth potential. It can help make our societies more resource efficient and more environmentally friendly and can improve city functions. What trends are we seeing and what impact might they have? For one thing, underground storage will probably be used more to integrate users with varying heating and cooling needs. The systems that are built will probably be bigger and deeper. Cooling will likely become increasingly important. As awareness increases, the technology will likely spread to a greater variety of end users. For the people in (and outside of) the city, this can mean less noise, less pollution and improved city functions – such as cooling in elder care homes and less slippery infrastructure in winter. On a societal level, less money on heating and cooling bills also means more money to spend on core functions for hospitals, homeowners, etc.

5.3 TRENDS FOR GEOTHERMAL STORAGE

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6.HYDROGEN STORAGE – ENERGY ON THE GO

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BOX 8: HYDROGEN STORAGE MYTHS

HYDROGEN IS TOO DANGEROUS TO EVER USEThe 1937 Hindenburg disaster is probably the best-known hydrogen-related accident. Although the definitive cause of the explosion remains unknown, investigations in the 1990s showed that the main cause may have been an electrical storm during the airship’s docking which resulted in ignition of its flammable coating. The hydrogen burned quickly, but the diesel fuel and coating burned for a couple of hours (flames are visible in famous footage of the disaster). Hydrogen is extremely flammable but, unlike petrol, hydrogen disperses rapidly into the atmosphere in the event of a leak. Hydrogen is not reactive at room tem-perature and water vapour forms when it burns.

HYDROGEN WILL BE BIG IN THE FUTURE, BUT IS NOT IN USE NOWHydrogen has been produced, stored, transported and used for decades. Hydro-gen is widely used in various industrial processes – e.g. in refineries, as a reduc-tion agent in the metallurgic industry and as raw material in the chemical indus-try. It is a basic element for the manufacture of ammonia, fertilisers and many polymers.36 A wide range of hydrogen-powered vehicles and stationary storage applications also exists.

A GREAT DEAL OF VARIOUS INFRASTRUCTURE IS NEEDED FOR HYDROGEN DISTRIBUTION AND USEThe existing natural gas infrastructure may be used to increase the share of hydrogen in heat and power production in Europe. In many countries the trans-mission network’s current infrastructure allows the transmission of up to 5–20 per cent of hydrogen.37 This amount of hydrogen in the fuel allows a continuous usage of existing installations without requiring adaptation and with no increased risk of damage. Hydrogen-burning natural gas turbines are also widely used today. Adding hydrogen provides a more efficient combustion process while reducing emissions of hazardous pollutants and greenhouse gases.

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BOX 9: HISTORY OF HYDROGEN STORAGE

Although hydrogen had been generated for many years, starting in the mid-1600s, hydrogen was first recognised as a substance discrete from other flammable gases by Henry Cavendish in 1766. The timeline below shows key events in hydro-gen’s history.

Hydrogen may be produced with diverse resources such as fossil fuels (natural gas and coal), biomass, nuclear energy and renewable energy sources (e.g. wind, solar power). The type of hydrogen produced from industrial conversion of fossil fuels generates emissions and is known as “grey hydrogen”. “Blue hydrogen” is produced when these carbon emissions are captured, stored or reused. “Green hydrogen” is generated by renewable energy sources with no carbon emissions (through the electrolysis process).38 Production of hydrogen from electricity is often called “power-to-gas”. The majority of hydrogen currently produced is grey hydrogen (see ill. 11). Hydrogen is converted back to electricity in the fuel cell.

6.1 HOW IS HYDROGEN PRODUCED?

Ill. 11: Hydrogen supply per production pathway. Source: IEA, 2019.

HYDROGEN PRODUCTION PER PROCESS

0

20

10

30

40

50

60

70

Mtons of hydrogen

0,4 0,1 0,3

Green hydrogen(as by-product)

Grey hydrogen(as by-product)

Green hydrogenBlue hydrogenGrey hydrogen

1766 – hydrogen recognised

2007 – fuel cells as stationary

backup power

1839 – first fuel cell

2008 – fuel cells used in passenger

cars

1960s – fuel cells used in

space missions

2009 – fuel cells as micro-CHP

units

1980s – fuel cells used in submarines

2010s – populari-sation of fuel cells

in society

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The use of hydrogen in a variety of applications (as shown in ill. 12), such as fuel for heating and transport, for seasonal storage or long-distance transport, is often referred to as the “hydrogen economy”. In this context, it is important that future hydrogen expansion is based on fuel derived from electrolysis processes, i.e. from renewable energy sources. One of the main challenges facing the establishment of the hydrogen economy is the current lack of excess renewable energy volumes sufficient to balance the relatively low efficiency of power-to-gas technologies.39

Furthermore, producing hydrogen from renewable electricity is much costlier than other pathways, such as production from natural gas (see ill. 13). According to the IEA, the cost of producing hydrogen from renewable electricity may decrease by 30 per cent by 2030 due to the declining cost of renewables and the scaling up of hydrogen production,40 although support for further expanding the necessary infrastructure and supply net-works is needed.

6.2 A HYDROGEN ECONOMY?

Ill. 12: The various uses of hydrogen

Ill. 13: Hydrogen production costs 2018. Source: IEA.

HYDROGEN PRODUCTION COSTS, 2018

0

2

1

3

4

5

6

8

7

USD per kg

RenewablesCoalNatural gaswith carbon capture

Natural gas

FUEL

• Transport• Electricity

generation

HEATING

• Industrial facilities

• Residential

INDUSTRIAL APPLICATION

• Chemicals (e.g. fertilisers)

• Products (e.g. steel)

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BOX 10: HOW FAR COULD A FAMILY GO WITH HYDROGEN?

A hydrogen-fuelled Toyota Mirai has a tank capacity of 5 kg41 and consumes 0.76 kg/ 100 kilometres (km) of fuel,42 and therefore has a range of around 650 km per refuelling. A typical European motorist travels 14,000 km in a year,43 and would thus need to refuel with hydrogen only 22 times per year. Today’s annual production of hydrogen, 69 metric tonnes (Mt), would be enough to fuel over 600 million cars.

Furthermore, the current annual production of hydrogen is equivalent to 2.3 GWh.44 The energy stored in the car’s 5 kg hydrogen tank is equivalent to around 167 kilo-watt hours (KWh). With the fuel cell’s efficiency at 60 per cent,45 the vehicle’s 120 litre tank filled with 5 kg of hydrogen can generate 100 kWh of electricity. Per capita household consumption of electricity in Europe is equivalent to 1,600 KWh per year.46 Accordingly, 5 kg of hydrogen can provide an entire week’s elec-tricity for a three-person family.

69 Mt of hydrogen

5 kg of hydrogen for driving 650 km

14,000 km driven per year

5 kg of hydrogen

600 million cars fuelled

1 week electricity supply for a family

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Despite promising potential due to its versatility and capacity for storing renewable energy, hydrogen has still not been widely adopted. Hydrogen is currently limited to small-scale storage applications and is mostly produced from processes that are not emission-free. Grey hydrogen production, for example, is responsible for annual CO2 emissions equivalent to the combined emissions of Indonesia and the United Kingdom.47 In order for citizens to adopt hydrogen to a greater extent, infrastructure for refuelling needs to be built and the public and private sector need to collaborate.

“AS WE USE MORE ELECTRICITY OVERALL AND AS THE DEPLOYMENT OF RENEWABLES INCREASES, WE SHOULD EXPECT HYDROGEN TO TAKE A LEADING ROLE, RATHER THAN THE MARGINAL ROLE IT NOW OCCUPIES.”

Hydrogen storage can work on both the small and large scale, storing energy locally but also capable of distribution through international supply networks. A simultaneous roll-out of the necessary fuelling infrastructure is a prerequisite for ensuring that demand will be properly met.

6.3 TRENDS FOR HYDROGEN STORAGE

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BOX 11: HYDROGEN STORAGE IN THE NEWS

BOTTLED HYDROGEN?Hydrogen’s gaseous form makes it difficult to transport and store. A French start-up is developing an innovative technology to enable easier hydrogen transportation and storage, accomplished by charging and releasing hydrogen in a unique liquid carrier.48

HYDROGEN IN THE STREETSNew actors in the market are including hydrogen in their plans for the first time. South Korea, for example, is planning to replace around 26,000 CNG buses with fuel cell buses by 2030.49 China is also decreasing its subsidies on battery elec-tric vehicles and placing new focus on fuel cell vehicles.50

HYDROGEN TRAINS BECOMING A TREND In 2017 Alstom and the local transport authority of Lower Saxony signed a contract for delivery of 14 hydrogen fuel cell trains (The Coradia iLint) which entered passenger service in 2018.51

HYDROGEN IN THE SKIES AGAINIn September 2016, the world’s first 4-seater hydrogen plane (aptly called the HY4) took off on its maiden flight from Stuttgart airport in Germany.52

HYDROGEN VESSELS FOR FOSSIL-FREE MARITIME TRANSPORTA liquefied hydrogen bunker vessel will provide bunkering services to merchant ships during open sea transport. The world’s first fuel cell ferry using hydrogen exclusively produced from renewables will operate around Scotland’s Orkney Islands and will be delivered in 2020.53, 54

HYDROGEN FOR A DECARBONISED STEEL INDUSTRYHydrogen will replace coal in the iron ore reduction process. A large-scale venture is planned by the HYBRIT project in Sweden.55 There are also plans to launch a similar project in Hamburg, Germany.56

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7.THE FUTURE CITY, A STORAGE CITY

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The future city is a storage city: a smart city where energy is needed on the go, a city where a large share of energy comes from renewable sources, a city where the internet-of-things allows communication between appliances and infrastructure. A future with battery-powered gadgets and vehicles, appliances, fuel cells and skyscrapers made of hydrogen-produced steel, thermal grids for heating entire neighbourhoods and cooling supermarkets. What will it take to integrate these technologies and what might the future city look like?

DAY-TO-DAY AND SEASONAL STORAGEThe key to smart urban energy storage lies in the combination of technologies. For day-to-day storage and electricity needs, the storage city will therefore include micro-grids that combine solar panels with Li-ion batteries to balance intermittent renewable energy supply and increase resilience in the event of power disruptions. For seasonal storage as well as heating and cooling needs, cheaper technologies with longer discharge dura-tion will be needed. Geothermal and hydrogen storage would fit this description, if economies of scale are achieved for such systems. There is no “one-solution-fits-all”, which is why we will need a combination of battery, thermal and hydrogen storage in the future city.

THE STORAGE CITY

Neighborhood batteries

Geothermal storage

Large-scale energy productionand storage

H2

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E-MOBILITY AND PORTABLE STORAGEE-mobility is expanding, and we now see electric cars, bikes, scooters and kick bikes in the streets. Soon these may be joined by more fuel cell vehicles running on hydrogen. Utilisation of all of these vehicles will be extended beyond their intended use as means of transport to also include energy storage: they will charge when renewable energy is abundant in the system and feed energy back into micro-grid’s battery when needed. Such vehicle-to-grid and vehicle-to-building systems may become more common when regulatory barriers are lifted. With portable storage with safer solid-state batteries and hydrogen bottles, our phones will never again run out of battery. The use of phase-change materials that store latent heat in self-warming clothes will also make it more comfortable to be outdoors in winter.

NEIGHBOURHOOD BATTERIES, THERMAL GRIDS AND THE VIRTUAL POWER PLANT CONCEPTTo maximise the system’s effectiveness and reduce investment risk, residents of a building or an entire building block could come together and invest in a neighbourhood battery or thermal grid. This would entail lower installation and maintenance costs per household and facilitate aggregation with other neighbourhood systems, forming a “virtual power plant”, a term used when smaller storage components aggregate. This may be easier to implement in countries such as Sweden, where formation of housing associations is an established practice. The storage city will heat icy pavements with geothermal and have battery-powered electric buses in traffic. The excess renewable generation outside the city limits (e.g. from solar and wind parks) will be stored in large-scale, cheaper sodium batteries and/or used for hydrogen production, transported through the adapted existing grids and then supplied to train and other systems.

THE NEW ENERGY TECHNOLOGY ECOSYSTEM INFLUENCED BY BEHAVIOUR AND PSYCHOLOGICAL DRIVERSThe economics of storage is improving and, in some cases, has reached cost-parity with conventional technology alternatives, although the still high upfront costs can discourage investments. Studies have shown that decisions regarding household con-sumption and choice of technologies are also influenced by behavioural aspects and are not purely driven by financial incentives.57

“NO MATTER THE DEGREE TO WHICH STORAGE SOLUTIONS ARE PERFECTED THROUGH CONTINUOUS RESEARCH AND DEVELOPMENT, THEIR FULL POTENTIAL WILL NOT BE REALISED UNTIL THE PUBLIC ACCEPTS, UNDERSTANDS AND DESIRES THESE TECHNOLOGIES.”

New technologies are more vulnerable to various misconceptions than are well-estab-lished technologies. A classic example of this vulnerability is the Hindenburg disaster, which occurred nearly one hundred years ago, and the role it played in hydrogen deployment. A disaster, a misapplication, higher than expected costs; there is little room for mishaps in the new energy technology ecosystem.

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Ill. 14: Historical growth of household solar panel and battery storage systems in Germany, combined with projected growth up to 2030 (assuming growth rate 40 per cent annually).

BOX 12: ADOPTION OF HOUSEHOLD BATTERY STORAGE IN GERMANY

Germany has been experiencing fast growth in the number of households choos-ing to install solar panels in combination with storage. Around 100,000 house-holds had installed such a system by the summer of 2018.59 Although this is a very small share (0.24 per cent) of the approximately 41 million German households,60 an additional 50,000 storage systems may be installed in German households in 2020 (a 50 per cent increase).61 To move beyond the tipping point (15 per cent household adoption), a minimum 40 per cent annual increase up to 2030 is needed (see ill. 14). This would involve nearly doubling the amount of installed systems every year. The historical pace between 2016 and 2018 has been on average 56 per cent, which is a positive indicator for future development. However, continuation of this trend requires strong governmental support in the form of incentives and subsidies, as well as cross-sectoral collaboration.

GERMAN HOUSEHOLDS WITH BATTERY STORAGE SYSTEMS

0

2,000,000

1,000,000

3,000,000

4,000,000

6,000,000

5,000,000

Number of households

20302025202020182013

TAILORING ENERGY SYSTEMS: ENERGY-STORAGE-AS-A-SERVICE Mobility-as-a-service, charging-as-a-service, subscriptions for food, accessories, films or music. Why not a subscription for energy storage? In the XaaS (anything-as-a-service) model the product becomes available to the customer as a service, normally at a monthly or annual fee. Energy-storage-as-a-service can curb the barrier of high upfront invest-ment costs, help aggregate multiple storage sources, and give the public the opportunity to test a solution without committing to a long-term investment. Regulatory and techni-cal uncertainties as well as lack of trust can be alleviated and give energy storage the head start it needs. As discussed in Section 1, around 15 per cent of users in a market need to adopt a technology for it to reach a “tipping point”. Are we close to this tipping point for energy storage?

There is certainly a long way to go, but we are working on it. Box 12 highlights the exam-ple of households adopting combined solar panel/battery storage systems in Germany. Market shares are still low, but the pace of growth is promising. Taking the example of heat pumps connected to shallow geothermal energy, the growth rate for new installations differs between European countries, but is typically 3–6 per cent per year. However, in the UK and Poland the number of new installations per year exceeds 10 per cent.58

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Ill. 15: Technology adoption rates, meas-ured as the percentage of households in the United States using a particular technology.62

TECHNOLOGY ADOPTION RATES FOR US HOUSEHOLDS

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10

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80

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%

Radio

Social media usage

Smartphone usage

Internet

Household refrigerator

Electric power

201920102000199019801970196019501940193019201908

Electric power Household refrigerator Internet Smartphone usage Social media usage Radio

One observable trend is that adoption curves for new technologies are becoming steeper over the years (see ill. 15).

The household refrigerator, for example, required 20 years to reach market-wide adop-tion in the US, and in the years prior to that, due to its high price, communities would invest in a common refrigerator until each household was able to afford one. If it took 40 years for electricity to become a household staple in the US and smartphones took around 10 years, how much time is needed for our cities to become storage cities?

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The drivers for energy storage and new energy carriers can be summarised as follows: Decarbonisation, Decentralisation, Circularity (DDC). Energy storage stands at the crossroads between the old and new energy landscape: it offers a unique opportunity for tailoring the energy system to urban needs in the climate change mitigation era, bring-ing cost-effective solutions with minimal environmental impact while exploiting what digitalisation has to offer in the smart city context. Our urban insight comes down to the need to allow more flexibility in energy systems. For this to happen, behavioural and regulatory changes are needed to allow expansion beyond the tipping point.

As our lives become more flexible, so do our energy needs. The demand for energy on the go, as well as the challenge of smoothly introducing renewable sources in energy systems, brings new energy carriers and storage solutions into the spotlight. Despite this, the full potential of energy storage is far from realised.

At the global level, energy storage can help curb climate change by decreasing emis-sions from electricity, heating and cooling needs. At the community level, energy stor-age can involve more resilient and flexible energy systems with higher levels of energy security through integration of locally produced energy. From the citizen perspective, energy storage holds the benefit of improved control of the costs and origin of their energy use. For the private sector, energy storage can open new business opportunities with constant innovation of offered services. These can range from energy-storage-as-a-service enterprises to market actors expanding to installation of storage systems, charging stations and virtual power plants.

The public sector has an important role to play in this context: setting an example by committing to net zero consumption and or/emission targets, or supporting the installa-tion of small-scale storage. Energy storage can secure critical infrastructure, hospitals and schools from disruptions, can help achieve ambitious energy and climate policy goals and push economic development through innovation. As shown previously, sup-port would be most needed until the time the tipping point is reached.

We propose that moving beyond energy storage’s tipping point requires particular focus on the following aspects: safety, automation and user-friendliness. Safety in terms of physical and digital security; standards need to be further developed and actors need to openly share data and experiences to identify risks and potential solutions.

Ill. 16: Drivers, trends and recommendations for the future storage city.

SECURITY

For citizens: physical and digital security

For countries: security of energy supply

AGGREGATION

Micro-grids & virtual power plant

Neighbourhood storage (battery, thermal)

USER-FRIENDLINESS

Energy-storage- as-a-service

Portable solutions

DECARBONISATION

DECENTRALISATION

CIRCULARITY The new energy ecosystem influenced by behavioural aspects (tipping point)

DRIVERS TRENDS

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“THE STAKES ARE HIGH, THOUGH: WE NEED TO BATTLE CLIMATE CHANGE BY REDUCING EMISSIONS. WE ALSO NEED TO REDUCE AIR POLLUTION, WHICH IS A GLOBAL PROBLEM THREATENING THE HEALTH AND LIVELIHOOD OF URBAN CITIZENS.”

Secondly, automation to dynamically manage stored energy (electricity and heat). This includes exploiting opportunities for communication between appliances and infrastruc-ture, as well as guidance and support for the development of micro-grids and virtual power plants.

Lastly, regarding user-friendliness, energy-storage-as-a-service is recommended. In order to achieve adoption before the tipping point, the solutions need to be visible and the benefits “stacked”; this requires a holistic approach when addressing energy stor-age in the urban planning context. Integrating multiple solutions improves the eco-nomic, social and environmental benefits of storage.

Nevertheless, behavioural aspects affect perceptions and new technologies are particu-larly sensitive to speculation and misconceptions. Lack of knowledge about the benefits of storage can cause resistance to the disruptive change energy systems are undergoing.

As we become more aware of the technologies surrounding us and their implications for our lives and our planet, many are embarking on a quest for more informed choices when it comes to urban energy use. The vulnerability of new technologies to miscon-ceptions and suboptimality is a threat: the ascent to the tipping point starts now.

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9.ABOUT THEAUTHORS

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Other contributors:Magdalena Lesińska, Junior Energy Engineer, Sweco PolandMagnus Lindén, Senior Energy Consultant, Sweco SwedenCecilia Wallmark, Head of Energy Strategies, Sweco Sweden

The authors would like to thank Prof. Björn Laumert and Dr. Monika Topel of the Department of Energy Technology at KTH Royal Institute of Technology for their valuable comments that helped improve this report.

LEAD AUTHORMARIA XYLIA, PHD, Expert in battery storage and energy systemsMaria Xylia is a senior energy systems analyst at Sweco Sweden with experience in the field of planning, policymaking and modelling of energy and transport systems. Maria holds a PhD in Energy Technology from KTH Royal Institute of Technology, specialising in optimisation of charging infrastructure placement. Her key competence areas include transport system analysis from the energy perspective, energy efficiency and energy storage technologies.

CONTRIBUTING AUTHORJULIA SVYRYDONOVA, Expert in shallow geothermal energy storageJulia has a MSc in Energy and Environmental Engineering from KTH Royal Institute of Technology and Politecnico di Torino and specialises in geothermal energy systems for heating and cooling at Sweco Sweden. She is the head of the geothermal energy unit. She specialises in dimensioning of geothermal energy systems, detailed systems design, ground source heat pump technology and energy calculations.

CONTRIBUTING AUTHORALEKSANDER KORYTOWSKI, Expert in hydrogen storageAleksander Korytowski is an energy engineer and project manager at Sweco in Poznań, Poland. He holds a MSc in Energy from Heriot-Watt University, Edinburgh and a MSc in Mechanical Engineering from Poznań University of Technology. His experience includes waste-to-energy plants, renewable energy strategies, alternative fuels, energy storage and energy recovery projects. Aleksander specialises in heat and power concept design, technical due diligence and implementation of innovative energy technologies.

CONTRIBUTING AUTHORSARA ERIKSSON, Expert in shallow geothermal energy storageSara has a MSc in Energy and Environmental Engineering from Lund University and works with systems for heating and cooling at Sweco Sweden. She has experience with systems including borehole systems, aquifer systems, cavern storage and high tempera-ture systems. Her specialties lies within dimensioning, detailed systems design and environmental permits.

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10.REFERENCES

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REFERENCES:

1) EASE & EERA, 2017. European Energy Storage Technology Development Roadmap (2017 update).2) Energy storage installed and used on site. Energy is generated by a behind-the-metre system (solar panels, wind turbine

etc.), stored in, for example, a battery, and used when needed. Excess energy may be fed back to the grid.3) International Energy Agency, 2014. Technology Roadmap Energy Storage, Paris. 4) IEA, 2019. Energy storage: tracking clean energy storage. Webpage (accessed 10 September 2019) 5) Energy storage technologies are usually grouped in 5 categories: chemical, electrochemical, electrical, mechanical and

thermal. For this report, we focus on one alternative from the following categories: electrochemical (lithium-ion (Li-ion) batteries), thermal (geothermal storage) and chemical (hydrogen storage). This choice is made based on the growth dynamics of these technologies. It is highly likely that more alternatives may come into the spotlight in the future. Some of these alternatives, such as sodium-ion batteries, are briefly discussed in this report.

6) European Commission. 2016. Towards a smart, efficient and sustainable heating and cooling sector. Webpage (acessed 2019-09-26) https://europa.eu/rapid/press-release_MEMO-16-311_en.htm

7) Eurostat, 2019. Energy consumption in households. Webpage (accessed 31 May 2019). https://ec.europa.eu/eurostat/statistics-explained/index.php?title=Energy_consumption_in_households

8) Eurostat, 2016. Ten things you didn’t know about heating and cooling, Webpage (accessed 31 May 2019). https://ec.europa.eu/energy/sites/ener/files/DG_Energy_Infographic_heatingandcolling2016.jpg

9) Eurostat, 2018. Climate change – driving forces.10) Eurostat, 2019. Energy for transport: 7.6% from renewable sources. Webpage (accessed 1 August 2019).11) Assuming an average smartphone with a 5.5 Wh battery which charges fully every day.12) Cleantechnica, 2019. Global Lithium Ion battery planned capacity grows 4percent in a single month.

Webpage (accessed 14 August 2019). 13) EASE & EERA, 2017. European Energy Storage Technology Development Roadmap (2017 update).14) Source: Sweco analysis with data from the U.S. Geological Survey, 2019. Mineral commodity summaries,

https://doi.org/10.3133/7020243415) Reserve: That part of the reserve base which could be economically extracted or produced at the time of determination.

The term “reserves” need not signify that extraction facilities are in place and operative. Reserves include only recovera-ble materials; thus, terms such as “extractable reserves” and “recoverable reserves” are redundant and are not a part of this classification system (U.S. Geological survey, 2019).

16) Resource: A concentration of naturally occurring solid, liquid, or gaseous material in or on the Earth’s crust in such form and amount that economic extraction of a commodity from the concentration is currently or potentially feasible (U.S. Geo-logical survey, 2019).

17) Alves Dias P., Blagoeva D., Pavel C., Arvanitidis N., Cobalt: demand-supply balances in the transition to electric mobility, EUR 29381 EN, Publications Office of the European Union, Luxembourg, 2018, ISBN 978-92-79-94311-9, doi:10.2760/97710, JRC112285.

18) Chemistry World, 2018. Battery builders get the cobalt blues. Webpage (accessed 28 April 2019).19) Bankmycell, 2019. How many phones are in the world with information from WorldoMetres U.N. data, GSMA Intelligence.

Webpage (accessed 15 June 2019).20) Home, 2018. Tesla leads electric vehicle race to cut cobalt dependency. Webpage (accessed 23 June 2019).21) IEA, Global EV Outlook 2019. IEA, Paris.22) This is based on the observation of Gordon Moore that the number of transistors on a microchip doubles every two years,

though the cost of computers is halved. This means that we get computers which are faster at lower costs. In other words, the microprocessors used in computers follow an exponential curve.

23) Favors, Z., Wang, W., Bay, H. H., George, A., Ozkan, M., & Ozkan, C. S. (2015). Stable Cycling of SiO2 Nanotubes as High-Performance Anodes for Lithium-Ion Batteries. Scientific Reports, 4(1), 4605. https://doi.org/10.1038/srep04605

24) Kato, Y., Hori, S., Saito, T., Suzuki, K., Hirayama, M., Mitsui, A., … Kanno, R. (2016). High-power all-solid-state batteries using sulfide superionic conductors. Nature Energy, 1(4), 16030. https://doi.org/10.1038/nenergy.2016.30

25) Jenaxinc, 2019. Batteries. Webpage (accessed 14 August 2019). 26) Dharmasena, R. D. I. G., Jayawardena, K. D. G. I., Mills, C. A., Deane, J. H. B., Anguita, J. V., Dorey, R. A., & Silva, S. R. P. (2017).

Triboelectric nanogenerators: providing a fundamental framework. Energy & Environmental Science, 10(8), 1801–1811. https://doi.org/10.1039/C7EE01139C

27) Liu, K., Liu, W., Qiu, Y., Kong, B., Sun, Y., Chen, Z., Cui, Y. (2017). Electrospun core-shell microfiber separator with thermal-triggered flame-retardant properties for lithium-ion batteries. Science Advances, 3(1), e1601978. https://doi.org/10.1126/sciadv.1601978

28) Illustration adapted from Jonsson, C.Offentliga fastigheter. 2017. Guide for geoenergy. Webpage (acessed 2019-09-26) https://webbutik.skl.se/bilder/artiklar/pdf/7585-572-1.pdf

29) Akademiska Hus. (n.d.). Karlstads universitet först i Europa som självförsörjande med värme och kyla. Retrieved 2019-09-11 from https://www.akademiskahus.se/ditt-campus/karlstad/karlstads-universitet/marklager-vid-karlstads-universitet/

30) Provoost, M., Albeda, L., Godschalk, B., van der Werff, B., Schoof, F. 2019. Geothermal Energy Use, Country Update for The Netherlands. European Geothermal Congress 2019. Retrieved at European Geothermal Congress 2019

31) Svenskt Geoenergicentrum. Geoenergins historia. Retrieved 2019-09-10 from http://geoenergicentrum.se/geoenergi-2/historia/

32) Sanner, B. (2019). Summary of EGC 2019 Country Update Reports on Geothermal Energy in Europe. http://europeangeothermalcongress.eu/wp-content/uploads/2019/07/CUR-00-Summary-Europe.pdf

33) Öresundskraft på okänd mark när värmelagring i berg testas. Retrieved from http://www.mynewsdesk.com/se/oresundsk-raft/pressreleases/oeresundskraft-paa-okaend-mark-naer-vaermelagring-i-berg-testas-2458272

34) Avinor, 2019. Renewable energy. Retrieved 2019-09-10 from https://avinor.no/en/corporate/airport/oslo/community-and-environment/energi/fornybar-energi

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35) Värmevärden. 2018. Invigning i Hudiksvall av ”Sveriges största ackumulator”. Retrieved 2019-09-10 from https://www.varmevarden.se/invigning-i-hudiksvall-av-sveriges-storsta-ackumulator/

36) Detlef Stolten, Bernd Emonts, Hydrogen Science and Engineering: Materials, Processes, Systems, and Technology,37) Blending Hydrogen into Natural Gas Pipeline Networks: A review of Key Issues, 2013

https://www.nrel.gov/docs/fy13osti/51995.pdf Injecting hydrogen into the gas network – a literature search, 2015 http://www.hse.gov.uk/research/rrpdf/rr1047.pdf

38) IEA, 2019, The clean hydrogen future has already begun, Webpage (accessed 10.07.2019) https://www.iea.org/newsroom/news/2019/april/the-clean-hydrogen-future-has-already-begun.html

39) Committee on Climate Change, 2018. Hydrogen in a low-carbon economy. https://www.theccc.org.uk/wp-content/uploads/2018/11/Hydrogen-in-a-low-carbon-economy.pdf

40) IEA, 2019). The Future of Hydrogen”, IEA, Paris. www.iea.org/publications/reports/thefutureofhydrogen/.41) Toyota Mirai Technical Specifications, Webpage (accessed: 14.06.2019)

https://media.toyota.co.uk/wp-content/files_mf/1444919532151015MToyotaMiraiTechSpecFinal.pdf42) H2, Toyota Mirai means “the future”, Webpage (accessed: 14.06.2019) https://h2.live/en/wasserstoffautos/toyota-mirai43) Odysse Mure, Distance travelled by car, Webpage (accessed: 14.06.2019)

http://www.odyssee-mure.eu/publications/efficiency-by-sector/transport/distance-travelled-by-car.html ACEA, Cars, Trucks & the Environment, Webpage (accessed: 14.06.2019) https://www.acea.be/uploads/publications/20100309_Brochure_Cars_Trucks_and_the_Environment-1.pdf

44) Equivalent to 8,28 TJ with hydrogen’s lower heating value at is 120 MJ/kg. (Source: NIST Chemistry Webbook).45) U.S. Department of Energy, Energy Efficiency & Renewable Energy, Fuel Cell Technologies, Webpage (accessed:

14.06.2019) https://www.energy.gov/sites/prod/files/2015/11/f27/fcto_fuel_cells_fact_sheet.pdf46) Eurostat, 2017, Households consumption of electricity per capita, Webpage (accessed 14.06.2019)

https://ec.europa.eu/ urostat/statistics-explained/index.php?title=File:Households_consumption_of_electricity_per_capita,_MWh_per_capita,_2015_new.png&oldid=347493

47) IEA, 2019. Hydrogen: A key part of a clean and secure energy future. Webpage (accessed 25 August 2019). https://www.iea.org/topics/hydrogen/whyhydrogen/

48) EDF, HySiLabs, the alternative hydrogen Supply, Webpage (accessed: 23.08.2019) http://hysilabs.com/ https://www.edf.fr/en/hysilabs-liquid-hydrogen

49) IEA Hydrogen, 2017, Global trends and outlook for hydrogen, Webpage (accessed: 12.06.2019) https://ieahydrogen.org/pdfs/Global-Outlook-and-Trends-for-Hydrogen_Dec2017_WEB.aspx

50) China Daily, 2019. Hydrogen vehicles on their way. Webpage (accessed 10 September 2019). http://global.chinadaily.com.cn/a/201904/11/WS5cae817fa3104842260b5819.html

51) Alstom, 2018, Coradia iLint – the world’s 1st hydrogen powered train, Webpage (accessed: 12.06.2019) https://www.alstom.com/our-solutions/rolling-stock/coradia-ilint-worlds-1st-hydrogen-powered-train

52) Composites Manufacturing, 2016, World’s First Four-Seater Hydrogen Fuel Cell Plane Has First Flight, Webpage (accessed: 12.06.2019) http://compositesmanufacturingmagazine.com/2016/10/worlds-first-four-seater-hydrogen-fuel-cell-plane-first-flight/

53) The Maritime Executive, 2019, Liquefied Hydrogen Bunker Vessel Designed, Webpage (accessed: 12.06.2019) https://www.maritime-executive.com/article/liquefied-hydrogen-bunker-vessel-designed

54) Wilhelmsen, 2019, New design makes liquefied hydrogen bunker vessels a reality, Webpage (accessed: 12.06.2019) https://www.wilhelmsen.com/media-news-and-events/press-releases/2019/new-design-makes-liquefied-hydro-gen-bunker-vessels-a-reality/

55) Hybrit, HYBRIT – towards fossil-free steel, Webpage (accessed: 11.06.2019) http://www.hybritdevelopment.com/ Brochure: https://ssabwebsitecdn.azureedge.net/-/media/hybrit/files/hybrit_brochure.pdf?m=20180201085027

56) ArcelorMittal, 2019, World first for steel: ArcelorMittal investigates the industrial use of pure hydrogen, Webpage (accessed: 13.06.2019) https://corporate.arcelormittal.com/news-and-media/news/2019/mar/28-03-2019

57) Huijts, Molin & Steg, 2012. Psychological factors influencing sustainable energy technology acceptance: A review-based comprehensive framework. Renewable and Sustainable Energy Reviews, 16 (1), 525 – 531

58) Sanner, B. (2019). Summary of EGC 2019 Country Update Reports on Geothermal Energy in Europe. http://europeangeothermalcongress.eu/wp-content/uploads/2019/07/CUR-00-Summary-Europe.pdf

59) Energy storage news, 2019. Germany reaches 100000 home battery storage installations. Webpage (accessed 1 August 2019). https://www.energy-storage.news/news/germany-reaches-100k-home-battery-storage-installations

60) Statistisches Bundesamt (Destatis), 2019. Households and Families. Webpage (accessed 1 August 2019). https://www.destatis.de/EN/Themes/Society-Environment/Population/Households-Families/_node.html

61) GTAI, 2019. The Energy Storage Market in Germany. Webapage (accessed 1 August 2019). https://www.gtai.de/GTAI/Content/EN/Invest/_SharedDocs/Downloads/GTAI/Fact-sheets/Energy-environmental/fact-sheet-energy-storage-market-germany-en.pdf?v=12

62) OurWorldInData (2019) via Comin and Hobijn (2004) and others.

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URBAN INSIGHT 2019

URBAN ENERGY

RACE TO ELECTRIFICATION

– NORWAY IN

THE STARTING GRID

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The theme for 2019 is Urban Energy, describing various facets of sustainable urban develop-ment as regards energy usage, renewable energy and energy efficiency – with future challenges and opportunities in the new energy landscape.

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2019 URBAN ENERGY REPORT BEYOND THE TIPPING POINT: …€¦ · In this Urban Insight report, Sweco experts debunk common misconcep-tions about some of the most promising energy storage