Energy in Cities

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Energy in Cities

Energy in Today’s Smart Cities

Taking action on climate change in cities is really important if we want to reach our goal of net-zero emissions. Cities are a big deal! They’re where more than 50% of the world’s population lives, 80% of the world’s GDP is produced, 75% of the world’s energy is used, and they produce over 70% of the world’s carbon emissions each year. And this is only going to increase! By 2050, it’s expected that over 70% of people will live in cities, which means an increase in energy demand in urban areas in the future1International Energy Agency, “Empowering Cities for a Net Zero Future.” 2021, https://www.iea.org/reports/empowering-cities-for-a-net-zero-future.

What is decarbonisation?

Okay, so “decarbonisation” sounds like a big word, but it simply means cutting down on CO2 and other greenhouse gases (GHGs). We need to decarbonise to reach net-zero, which means balancing the GHGs we emit with what we remove from the atmosphere. To do this, we need a multifaceted approach, including:

  1. overall energy reduction
  2. a shift to renewable electricity replacing fossil fuels
  3. increased sustainable and regenerative practices
  4. CO2 removal through both natural and artificial methods

Achieving net-zero by 2050 necessitates these changes across all sectors, including energy, transportation, construction, production, and waste management.

Since cities use so much energy, they’re really important in this whole “decarbonization” process. We can use cool technology like smart devices, apps, and big data to help make changes happen faster and smarter. This tech can also help cities plan better and make sure the power system works really well2International Energy Agency,” Empowering Urban Energy Transitions, Smart cities and smart grids.” 2024. https://www.iea.org/reports/empowering-urban-energy-transitions. It can also help make things more efficient and manage city services in real-time3International Energy Agency, 2021.

Making cities cleaner is a big job, and there’s no one easy way to do it. Every city is different, so they’ll need to find solutions that work best for them. But lots of cities around the world are already doing amazing things to cut emissions. This gives us hope that we can keep the planet from getting too hot and reach net-zero by 20504United Nations, “Net-zero commitments must be backed by credible action”. No Date. https://www.un.org/en/climatechange/net-zero-coalition#:~:text=Currently%2C%20the%20Earth%20is%20already,reach%20net%20zero%20by%202050.

What does energy generation and provision in cities look like?

To be able to design and implement the measures needed to meet net-zero goals in the energy sector by 2050, first we need to understand how energy is generated and supplied to a city. It’s actually pretty complex! Cities get energy from lots of different sources and have a complex network of generation, transmission, and distribution systems that work together to make sure cities always have the energy they need.

Electricity supply:

So, how does electricity get to us? It all starts at power plants with electricity generation, i.e. the process of transforming primary energy from fossil fuels like coal, natural gas, or renewable sources like wind or sun into a usable secondary form of energy, namely electricity.

Once generated, we use special machines called transformers to step up the voltage for long-distance transportation. Stepping the voltage up ensures minimal power loss in transportation. These high-voltage power lines carry electricity over long distances from power plants to substations near populated areas.

At these smaller substations, we use transformers again to bring the voltage back down to a safer, lower level suitable for local distribution. From here, electricity travels through a network of distribution lines that branch out to power homes, businesses, and everything else in the city.

FIG. 1: Outlining electricity source, transmission, distribution5Seattle Government, “Power Supply and Delivery”. No Date.  https://www.seattle.gov/city-light/energy/power-supply-and-delivery

  1. Power is generated from various sources (fossil fuels, nuclear, and renewables)
  2. The substation transformer steps up the voltage for transmission
  3. Transmission lines carry electricity over long distances
  4. Substation transformer steps down the voltage
  5. Distribution lines carry electricity to residents
  6. Transformers on poles step down electricity before it enters the residence
  7. Service lines deliver power from the pole to the residence

Natural Gas supply:

Besides electricity, cities also get energy from natural gas, which is delivered through an extensive network of gas pipelines. The journey starts at extraction wells, after which the gas is cleaned at special plants to produce what is known as ‘pipeline quality’ dry natural gas.

The cleaned gas is then moved through underground long-distance transmission pipelines to smaller distribution pipelines that eventually bring it right to the people’s homes or businesses. Along the way, compressor stations ‘push’ the gas along and keep it moving by changing the pressure in the pipes.

Natural gas is used for lots of stuff! It heats our homes, helps us cook, and is used in factories to make things like cement, steel and ceramics. It’s even used to make electricity at some power plants right in the cities.

FIG. 2: Natural gas supply chain through production, transmission and distribution6Australian Energy Market Commission, “Gas Supply Chain”. No Date. https://www.aemc.gov.au/energy-system/gas/gas-supply-chain

As we have seen, the electricity and natural gas systems are complex and have to be managed really carefully. We have to make sure we have enough energy when we need it, keep everything safe, and also try our best not to damage the environment in the process. It’s all about finding the right balance.

What should the decarbonisation goal for cities be? The Carbon Law?

To stop the planet from getting too hot, we need to reach “net-zero” by 2050. As we saw before, net-zero means not adding more GHGs to the atmosphere than we take out (the goal set under the Paris Agreement).

To help reach this target, two scientists called Rockström and Gaffney have introduced the concept of the “Carbon Law”.  The Carbon Law advocates for halving global CO2 emissions every decade, aiming for net zero emissions by 2050. It also emphasises the importance of making the biggest cuts before 2030 7Johan Rockström and Owen Gaffney, “Breaking Boundaries – The Science of our Planet”. 2021 Penguin Random House., because the longer we wait, the harder it will be to get to net zero by 2050.

“Net-zero” doesn’t mean we’ll stop emitting GHGs completely. It means that where we cannot prevent the emissions, we will have to take the same amount out of the air. So, where it is not possible to eliminate emissions, we’ll have to ensure we remove an equivalent amount by planting trees or using modern technology to remove it.

In the graph below you will observe that the CO2 emissions are not expected to reach zero by 2050, but that the remaining +-5 GtCO2 will be removed through additional measures, such as natural and artificial CO2 carbon removal, thus reaching overall global net zero.

FIG. 3: The future of carbon – Stabilising global temperatures at around 1.5°C8Figure from:  Johan Rockström and Owen Gaffney, 2021, p. 125

Basically, to follow the “Carbon Law,” we need to seriously step up our game in all sectors, all around the world, and work together to make it happen.

Hear straight from Prof. Rockström on how to implement the Carbon Law:

How to implement the Carbon Law in cities?

Cities are where over 80% of the global GDP is generated! They use a lot of electricity and natural gas, which helps them grow and develop. But, to follow the “Carbon Law” and cut GHG emissions in half every ten years, cities need to make big changes without hurting their economies. As stated before, there’s no one easy way to do this, each city has to figure out what works best for them. But most cities will probably include these elements in their net-zero plan:

  • Electrification (include link to KP on Electrification)
  • Energy efficiency (include link to KP on Energy efficiency)
  • Switching to cleaner fuels where possible
  • Reduction of energy waste through digital technologies

Experts estimate that using digital technologies could reduce renewable energy wastage by over 25%, improve system efficiency by 30%, and lower customer costs by up to 30% by 20309International Energy Agency, 2024.

Watch this video to understand the complexity of planning and implementing the energy transition in smart cities:

Case studies of measures taken by pilot cities to decarbonise:

  • Rio de Janeiro did something really cool in 2023! They became the first city in Latin America to buy clean energy (like solar or wind power) for their public buildings. They signed a long-term deal with a renewable energy company, which means they get stable prices and can keep working towards their environmental goals. It’s a win-win10C40 Cities, “Empowering all: The just energy transition in Latin America”. C40 Cities.  2023. https://www.c40.org/news/empowering-all-the-just-energy-transition-in-latin-america/.
  • Vancouver is making it easier for people to drive electric cars. Now, every new apartment building has to put charging stations in each parking spot! This way, it’s way simpler for people living in apartments to charge their EVs. Cities can also work together to buy lots of clean energy, which makes it cheaper for everyone.
  • To make sure important places like hospitals or schools always have power even if a blackout should happen, cities like Utrecht in the Netherlands are coming up with smart plans. Utrecht is using a system where electric cars can actually give power back to the grid when it’s needed! So, cars charge during the day, and when everyone gets home and uses lots of electricity in the evening, the cars serve as battery backup. They’re planning to connect thousands of cars to do this!
  • Cities are also using nature to stay cool. In Melbourne, Australia, they’re planting 3,000 trees every year to lower the city temperature. That means people don’t need air conditioning as much and they get more parks! In Medellin, Colombia, they made “green corridors” and cooled the city down, too11International Energy Agency, 2024.

Taking a multi-faceted approach to energy in cities

Meeting the “Carbon Law” goals and getting to net zero by 2050 requires a multi-faceted approach in cities that targets various sectors simultaneously. Cities must identify their own unique problems and targets and address these with solutions that fit their specific needs.

Targets for cities include:

  • Energy Transition: We need to cut way back on using coal, oil, and gas. Cities should switch to renewable energy like solar and wind power, and make it easy for homes and businesses to put solar panels on their roofs. This includes electricity generated and distributed on the centralised system as well as making decentralised electricity generation, like community and private generation, possible. All solutions will complement each other in reaching the Net Zero end goal.
  • Building Efficiency: Cities can make old buildings more energy efficient by adding insulation and better windows. New buildings should be super energy-efficient and use standards like LEED or the Passive House certifications.
  • Sustainable Transportation: Cities should encourage electric or hydrogen cars, build more charging stations, and help people drive less. They can improve buses and trains, make it easier to walk or bike, and maybe even charge extra for driving in busy areas.
  • Waste Management: Cities need to reduce the amount of trash they produce, recycle more, and turn some trash into energy.
  • Urban Planning and Greening Public Spaces: Smart planning means adding parks and trees to soak up CO2, having gardens in the city, and designing things so people don’t have to travel as far and can use public transport more.
  • Legislation and Policy: Cities need strong rules to protect the environment, maybe even make polluters pay. They can also give money or rewards to people and businesses that use clean energy.
  • Community Engagement and Education: Cities should teach people why cutting pollution is important and get everyone excited about helping out.
  • Monitoring and Reporting: Cities need to keep an eye on their carbon emissions and inform everyone about their progress. That way, they can make changes if needed.

By doing all these things, cities can really help stop climate change. It takes everyone: governments, businesses, and all the people living in the city working together to build a clean future.

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These articles have been reviewed using AI in order to align the style and length of each article. The research and content are original to the authors noted.

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