Lecture 2: What Is the Role of Cities in Decarbonization?

TL;DR

A sustainable urban energy system requires total conceivable sustainable production to meet or exceed total energy consumption. Lecture 2 compares consumption from transportation, heating and cooling, lighting, information systems, food, and manufacturing with sources such as wind, solar, hydropower, geothermal, and nuclear. Read on to understand the balance-sheet framework, available energy sources, and the physical meaning of energy.

Transcript

[SQUEAKING] [RUSTLING] [CLICKING] DAVID HSU: Hi, everyone, and welcome back to the MIT class on urban energy systems. Wherever you're seeing this lecture, please subscribe. You can either find it on the web page where you found this video or ask the instructor. So let's get back to the topic for today, which is going to be cities and decarbonizatio... Read More

Key Insights

• "the challenge is to try to put these two in balance" (3:15)
• "we have many sustainable technologies that could produce energy" (4:27)
• "a tremendous amount of energy goes into growing and transporting and keeping our food cold" (3:57)
• "it is low carbon but as I said in an earlier class we have questions about how do we handle the fuel for nuclear power plants" (5:29)

Questions & Answers

Q: What is the main topic of Lecture 2: Cities and Decarbonization?

The lecture examines the role of cities in decarbonization and how cities can take action. It introduces a balance-sheet framework for comparing energy consumption with conceivable sustainable energy production.

Q: What makes an energy system sustainable?

A sustainable energy system has total conceivable sustainable production that is greater than its total consumption. The goal is to replace the current level of consumption entirely with renewable resources.

Q: What makes an energy system unsustainable?

An energy system is unsustainable when total energy consumption is larger than total conceivable sustainable production. The challenge is to bring these two sides into balance while meeting societal energy needs.

Q: What are the main forms of energy consumption?

The lecture identifies transportation, heating and cooling, lighting, information systems and other gadgets, food, and manufacturing. Transportation includes cars, planes, and freight, while food requires energy for growing, transporting, and keeping it cold.

Q: Which sustainable energy sources does the lecture discuss?

The sustainable production stack includes wind, solar, biomass, hydroelectric power, wave energy, tide energy, geothermal energy, and nuclear power. Solar energy can be harnessed through solar cells, thermal energy, and biomass.

Q: Why does the lecture place a question mark beside nuclear power?

Nuclear power is low carbon, but the lecture says it is unclear whether it counts as sustainable. Questions remain about handling nuclear fuel and waste and whether nuclear power will be fully sustainable in the long run.

Q: How can the balance between energy consumption and sustainable production change over time?

Both sides can change as expectations around consumption evolve. Technologies, institutions, and markets for sustainable production can also change the amount of conceivable sustainable energy available.

Q: What is energy, according to the lecture?

Energy is described as the quantitative property of doing work. It can be neither destroyed nor created, but it can be transformed into light, heat, or mass.

Summary & Key Takeaways

• Cities hold the key to decarbonization efforts, as they are responsible for a significant portion of greenhouse gas emissions.

• The shift towards decarbonization requires a balance between energy consumption and production, with a focus on renewable energy sources.

• Sankey diagrams provide a visual representation of the energy flow, highlighting the need for more efficient energy use and a transition to renewable energy sources.