IPCC 2021 – Energy Security in Africa

Climate Change Quality Mark Content
  • The focus of these resources are to explore climate change and energy security in Africa.
  • Hydro electric power has been identified as a more sustainable way for Africa to achieve energy security in the future.
  • Throughout the continent of Africa there are already many hydroelectric power stations, with many more planned over the coming decades.
  • Climate change could potentially impact upon these plans. These resources focus upon that relationship.

Physics – Egypt’s Benban Solar Farm

In this resource linked to COP27 in Egypt, physics students explore renewable energy production.

Learning Objectives

  • Recognise that solar power is a renewable energy source of great value in Egypt
  • Describe the energy transfer in a solar cell
  • Evaluate the energy dissipated in the Benban solar farm
  • Calculate the cost of the energy produced using the formula cost = power (kW ) x time (hours) x price (per kWh).

Motivation/Outline

In its acceptance speech at COP26, Egypt celebrated its renewable energy resources:

This is an extract from https://unfccc-cop26.streamworld.de/webcast/closing-plenary-of-the-cop-followed-by-cmp-and-c-2 from 09:20

Egypt transitioned from the traditional energy sources to renewable, more sustainable and planet-friendly energy sources…

One of these resources is the huge Benban solar farm.

Lesson Introduction

Watch the relevant part of the COP26 plenary video and/ or

  • The Benban solar farm was supported by the Green Climate Fund. Contributions to the Green Climate Fund were one of the areas which didn’t make as much progress as was hoped at COP26 in Glasgow, 2021.
  • COP27 will be at Sharm El-Sheikh in Egypt in November 2022.
Benban - map
Benban map

images from google maps

Discussion points:

  • What is a renewable energy source?
  • Why is it important to develop renewable energy sources?
  • What is a solar cell and how is it different from a solar panel? Where have people seen solar cells/ panels?
  • What makes a location suitable for a huge solar energy farm? (space, sunshine, access for bringing the equipment in and getting the electricity out…)
  • Could we build such a huge solar park in the UK? (no, we don’t have a big desert, but you could research some UK solar farms)
  1. Use https://globalsolaratlas.info/map to compare the global horizontal irradiation where you live with that in Benban. (for Benban the value is given as 2366 kWh/m2).
    Global horizontal irradiation is the total amount of solar energy reaching a 1m2 horizontal surface on the ground in a year.

    Discussion point: What is a kWh? (if 1 kWh is the electrical energy converted by a 1 kW appliance used for 1 hour rephrase this in terms of electrical energy generation. See https://www.bbc.co.uk/bitesize/guides/z2h4dxs/revision/1 for more detail)

    Discussion point: So what is a kWh/ m2?

    Extension: Express this answer as a proportion or percentage

  2. Discuss: what is the initial store of energy and by what pathways is it transferred? (nuclear store in the Sun, energy is transferred by light from the Sun to the panel and is transferred electrically from the panel to homes and businesses)
  3. The size of the Benban solar farm is 37.2 km2. Calculate the total energy carried by the light arriving at the site.

    (37.2km2 = 37 200 000m2 so 2366 x 37 200 000 = 88,015,200,000 kWh = 88 015.2 GWh = 88.0TWh)

    Discuss: kilo, mega, giga, Tera etc.

  4. The estimated output from Benban is 3.8TWh. How much energy is not converted usefully?
    88.0-3.8 = 84.2TWh

    Extension – write this as a proportion or percentage
    Discussion – why so much? Solar panels don’t cover the whole of the ground, solar panels are actually less efficient when they get hot, you can see solar panels, so they must be reflecting some of the Sun’s light, not absorbing it all etc.)

  5. What is the current electricity price in your region? (see https://www.ukpower.co.uk/home_energy/tariffs-per-unit-kwh and scroll down for regional breakdown).
    What is the value of the energy the Benban solar farm will produce during COP27, which is scheduled to last 2 weeks (assume there are 52 weeks in a year)?

    (cost = power (kW ) x time (hours) x price (per kWh).
    So value = 3, 800, 000, 000 kWh x 2/52 x 28.34 = £41,420,000.

    Discussion – is that surprising?

    Why might the quantity of electricity produced actually be different? (We started with an annual value, but the seasons and the weather will actually have an impact on how much is produced in a given week).

verified climate education resources

UK Energy Mix

In this activity students use current data to investigate  the UK’s energy sources.

Go to gridwatch.co.uk and use the table and the key at the bottom of the page to complete the following table. This website shows you where the UK’s electric power is coming from and what the total demand (use) is and has been over the past year.

(1 GW = 1 000 000 000W)

energy source table
  1. In some of the boxes, you may see a negative number – what does that mean?
  2. What is the total net amount of power we are currently getting from France, the Netherlands, Belgium and Norway?
  3. For the power generated in the UK, highlight all renewable energy sources.
  4. What is the total amount of power we are currently generating from fossil fuels in the UK?
  5. Looking at the graph headed ‘yesterday’, when would have been the best time to charge an electric car, if you wanted to use as much renewable power as possible? Why?
  6. Looking at the graph headed ‘last year’ which season(s) have the most energy generated by solar energy?
  7. Which season(s) have the most energy generated by wind energy?

Extension

By looking at the total energy demand, and the production by wind energy, what can you deduce is the purpose of gas turbines?

Can you see any correlation between wind output and gas turbine output?

Opportunity for Group Work

Make a poster or presentation showing what you have learned.

Sankey Diagrams for Physics

Energy and Climate Change

Energy is needed in the form of electricity to power our lives, and to fuel our travel and industry. Since 1990, total world energy consumption has increased by over 55% and is projected to increase by another third by 2040.

Globally, oil accounts for over 30% of total energy use, followed by coal, gas and nuclear at 4%. This mix is different when you look only at electricity production, and different again on a country by country level.

A sustainable energy transition is a shift from an energy intensive society based on fossil fuels to energy efficiency with low carbon and renewable energy sources.

The Paris Agreement is a legally binding global climate change agreement, adopted by 189 nations at the Paris climate conference (COP21) in December 2015. It sets out a global framework to avoid dangerous climate change by limiting global warming to well below 2°C and pursuing efforts to limit it to 1.5°C.

Significant changes in energy production, transmission and use are necessary to achieve these commitments.

This should lead to co-benefits including improved air quality and reductions in energy poverty.

Since 2019, the costs of developing new power plants based on hydroelectric power, onshore wind, solar photovoltaic (PV), biomass and geothermal energy have become comparable to the costs of new oil and gas fuel plants.   

Physicists play an essential role in all aspects of climate change research and policy decisions as well as in development of technologies and new ideas for preventing and mitigating the effects of future, damaging climate change.

Energy and Core Physics

 

Energy is a fundamental concept in physics and a key topic in any physics curriculum. The Earth’s climate system is driven by energy stores and transfers. Development of clean, sustainable energy generation and distribution methods relies on understanding the core physics involved. The climate system and sustainable energy production therefore provide engaging and relevant sources of examples for enhancing the teaching and learning of energy as a topic in Physics. They give teachers an obvious opportunity to engage their students in an appreciation of the importance of the physics already in the school curriculum in solving many of the problems surrounding accelerated climate change, as illustrated in the following, brief summary of potential links.

Energy is transferred by radiation from the Sun, increasing the thermal store in the Earth’s atmosphere and ocean systems. Energy transfers within these systems take place through the physical processes of conduction, convection, radiation and changes of state. Seasonal and longer term, natural variations in heating and cooling of the Earth are a result of the alignment of the Earth in space and its orbital motion around the Sun. Land and ice surfaces are heated differentially according to the absorptive or reflective nature of the surface type and rocks are heated internally due to energy released during radioactive decay and large scale, convective motion of the Earth’s interior.

Successful and sustainable, low carbon generation of electricity to meet current and future demands relies on understanding and exploiting many of these natural, physical processes. Atmospheric convection causes winds to drive wind turbines and also generates the ocean waves exploited in wave power devices. The relative motion of the Earth, Moon and Sun causes the ocean tides exploited in tidal barrages and undersea-current driven turbines. Seasonal changes, weather patterns and latitude can all affect the output of solar energy devices as can reflection and absorption of radiation by the materials they are made from. Geothermal energy relies on energy transfers due to radioactive heating of rocks, local volcanism or simply the heat capacity of the soil acting as a thermal store of energy.

Many large-scale electricity generation methods depend on the basic principle of a turbine turning a generator which relies on understanding the principles of electromagnetic induction and factors affecting potential power output and efficiency. Electricity distribution on a large scale, via the National Grid, involves minimising energy dissipation into the surroundings by transmitting electricity at very high potential difference and low current thus reducing thermal transfers of energy within the cables. Domestic uses of electricity involve devices with varying levels of energy efficiency and informed choice of the most efficient appliances and how long they are used for can lead to reductions in an individual’s energy demands, carbon footprint and household bills.

Energy Efficiency

Improving energy efficiency saves individuals money, reduces waste, conserves resources and cuts emissions of greenhouse gases and other pollutants. Discussing personal, financial savings and more immediately obvious environmental impacts can lead to engagement with climate change by an indirect route with valid applications in the physics curriculum. This is also a good opportunity to reinforce accurate vocabulary using the terms energy stores, transfers and pathways as well as the concept of energy dissipation and avoiding terms such as energy saving (https://spark.iop.org/collections/energy-new-curriculum). Examples can be given of more relevant applications of the Sankey Diagram as a tool for accounting for energy transfers in the atmosphere:

(see also http://www.sankey-diagrams.com/greenhouse-effect-explanation-with-sankey-diagram/ and https://www.metlink.org/wp-content/uploads/2020/11/PhysRev-25_energybudgets.pdf)

Sankey energy diagram

By Cmglee – Own work, CC BY-SA 3.0

This could be used to illustrate a more complex example of a Sankey diagram and lead to a discussion of the possible effects of changes to some of the pathways, reinforcing the concept of energy conservation as both sides must remain balanced.

Wind Turbine Example 

In a wind turbine, 20% of the energy from the wind is converted to electricity. Lost wind leads to a loss of 30 % of the energy, friction between the wind and the blades of the turbine and the wind leads to a loss of 25% of the energy, and the rest of the energy is lost due to friction in the electric generator.

  1. How much energy is lost due to friction in the generator?

2.   Draw a Sankey diagram for the wind turbine, considering that the output in electrical energy is 20 kJ.