Royal Institution — June 2015

## Sustainable Energy – without the hot air

David MacKay FRS

Department of Engineering
University of Cambridge

Department of Energy and Climate Change
United Kingdom Government

# Why climate change action is difficult, and how we can make a difference

 wie breit müsste die Biokraftstoff-Plantage sein?
 wie breit müsste die Biokraftstoff-Plantage sein?

One lane of cars

60 miles per hour

30 miles per gallon
1200 litres of biofuel per hectare per year
80 metres car-spacing

One lane of cars

60 miles per hour
30 miles per gallon
1200 litres of biofuel per hectare per year
80 metres car-spacing

= 8 kilometres wide

## This book is free online

www.withouthotair.com

## This book is free online

www.withouthotair.com

# Climate science

## The size of future climate change depends on cumulative emissions

DECC/Met Office, adapted from IPCC 5th Assessment Report (2013)
Global-mean surface temperature 1880-2013 (NASA GISS data)
Grey line shows annual values, the blue line a LOESS smooth
^
Sea level 100m lower than today

## The size of future climate change depends on cumulative emissions

DECC/Met Office, adapted from IPCC 5th Assessment Report (2013)

# Energy arithmetic

## A rough guide to sustainable energy

### Examples

• one lightbulb for 24 h - 1 kWh
• food - 3 kWh / day (*)
• bath - 5 kWh (*)
• litre of petrol - 10 kWh
• aluminium can - 0.6 kWh

80 kWh per day

80 kWh per day

26 kWh per day

### June 2007

'If every London household unplugged their mobile phone chargers when not in use,
we could save 31,000 tonnes of CO2 and 7.75m per year.'

## Numbers

 Energy saved by switching off for one day = Energy used by driving an average car for one second 0.5 W × 86,400 s = 40,000 W × 1 s

## Numbers

 Energy saved by switching off for one day = Energy used by driving an average car for one second 0.5 W × 86,400 s = 40,000 W × 1 s 0.01 kWh
 Transport Heating Electricity

UK energy consumption:

125 kWh per day
per person

and more,
if we take
into account imports

90% fossil fuels

## A rough guide to sustainable energy

### Examples

• one lightbulb for 24 h - 1 kWh
• food - 3 kWh / day (*)
• bath - 5 kWh (*)
• litre of petrol - 10 kWh
• aluminium can - 0.6 kWh

### Population density: square metres per person

 UK: 4000 m2 per person 250 people per sq km

### Power per unit area: W per square metre

(point size shows land area)

Photo provided by the University of Illinois

## Plant power per unit area

* assumes genetic modification, fertilizer application, and irrigation
For sources, see D J C MacKay (2008) Sustainable Energy - without the hot air

## Powers per unit area of British wind farms, v farm size

20 W/m2

Data and photo by Jonathan Kimmitt - 25 sq m of panels

Bavaria Solar Park: 5 W/m2
www.powerlight.com

3.8 W/m2
Photo by Robert Hargraves
Data from www.allearthrenewables.com

14 W/m2
www.stirlingenergy.com

## Andasol, Spain

10 W/m2
 RWE.com

## PS10, Solucar

5 W/m2
 Photo by afloresm

## All renewables are diffuse

 Wind 2.5 W/m2 Plants 0.5 W/m2 Solar PV panels 5–20 W/m2 Tidal pools 3 W/m2 Tidal stream 8 W/m2 Rain-water (highlands) 0.24 W/m2 Concentrating solar power (desert) 15–20 W/m2
 Fission: 1000 W/m2

## Demand-side options – Transport

Have small frontal area per person
Have small weight per person
Go slowly
Convert energy
efficiently

## We need a plan that adds up —

... every month, every day, and every hour!
 Electricity, gas, and transport demand; and fictional wind (assuming 33 GW of capacity), all on the same vertical scale.

# Why climate change action is difficult

## The 2050 Calculator

2050-calculator-tool.decc.gov.uk
2050.edp.pt
www.wbc2050.be
www.wbc2050.be
china-cn.2050calculator.net
2050.sejong.ac.kr

# What we need for most 2050 pathways

## What we need for most 2050 pathways

Thermablok

### Electric vehicles

• batteries
• capacitors
• light-weighting
• fly-wheels

## What we need for most 2050 pathways

### Cheaper wind, especially offshore

2benergy.com
Makani Power
 Makani Power

## What we need for most 2050 pathways

### Waste-to-good stuff

• what are the best uses of biomass?

## What we need for most 2050 pathways

### Proliferation-resistant, safe, low-waste nuclear power

Jules Horowitz materials test reactor

## What we need for most 2050 pathways

### Carbon capture and storage at scale

 NET Power, LLC

## What we need for most 2050 pathways

### Energy storage

 Dinorwig - 10 GWh energy; 2 GW maximum power

## What we need for most 2050 pathways

### Backup plans

• eg, in case low-cost electric vehicles don't materialise
• hydrogen, ammonia

• in case sustainable bioenergy can't be delivered
• air-fuel synthesis

• or in case climate sensitivity turns out on the big side
• geoengineering research

## What we need for most 2050 pathways

### Well-trained engineers

 'Okay - it's agreed; we announce - "to do nothing is not an option!" then we wait and see how things pan out...' Lowe, Private Eye

# Why climate change action is difficult

## Why DECC's work is difficult – Reflections on 5 years in the Department of Energy and Climate Change

David MacKay FRS

Department of Engineering
University of Cambridge

Department of Energy and Climate Change

# Why DECC's work is difficult

## The 2050 Calculator

2050-calculator-tool.decc.gov.uk

- example 1

## Which is more valuable?

1 cup of boiling water and nine cups of ice-cold water

## or

10 cups of water at 10 °C?

[The quantities of heat are identical]

The value of heat depends on its temperature

## Standards for Heat-pump Installations

Chris Wickins and the Microgeneration Certification Scheme Heat-pump Working Group

- example 2

Source: IPCC

## Policies

• Renewable transport fuel obligation
• Renewable obligation
• Renewable heat incentive
• International negotiations: prevention of deforestation

Vancouver to Immingham: 8888 nautical miles

## "BEaC"

Using these assumptions, and assuming all harvested wood goes to power station
Area required for 30 M odt/y of pellets, delivering roughly 35 TWh/y:

## "Renewable" target misaligned with energy security and with value-for-money

 Electricity price in pounds per MWh

www.energy-charts.de

Electricity production in Germany: Week 29

Graphs: B Burger, Fraunhofer ISE; data: EEX Transparency Platform

Electricity production in Germany: Week 25

Graphs: B Burger, Fraunhofer ISE; data: EEX Transparency Platform

## Lowest demand in Summer, 2012

Source: National Grid 2013

simulation of 40 GW of solar capacity in the UK
clear-sky, partially sunny, overcast: 1, 0.547, 0.1

## Renewable target in conflict with energy efficiency

 Impington Village College

# Why climate change action is difficult

(at least, while low-carbon technologies are more expensive than fossil fuels)

NOT caps.

## This book is free online

www.withouthotair.com

# Spare slides

## Keeping energy demand and supply in balance

 Electricity, gas, and transport demand; and fictional wind (assuming 33 GW of capacity), all on the same vertical scale.

## How subsidies are often set

The "50th percentile" method for setting subsidies The "50th percentile" method for setting subsidies The "50th percentile" method for setting subsidies
The "50th percentile" method for setting subsidies

## How much bioenergy?

450ppm: 275 EJ/year primary energy, and 75% going to BECCS
550ppm: 200 EJ/year, 60% going to BECCS
baseline: 140 EJ/year

## 275 EJ/year

= 23 kWh/d/person × 9 billion people

assuming 0.5 W/m2, requires 17 million km2

roughly 10% of world's land surface area
roughly 17 Gt per year of biomass

Is there any inconsistency?

Page 73 of SR:
Rural areas are expected to experience major impacts on water availability and supply, food security, infrastructure, and agricultural incomes, including shifts in the production areas of food and non-food crops around the world (high confidence). These impacts will disproportionately affect the welfare of the poor in rural areas, such as female-headed households and those with limited access to land, modern agricultural inputs, infrastructure, and education. {WGII 5.4, 9.3, 25.9, 26.8, 28.2, 28.4,Box 25-5}

## "Limited Bioenergy":

"a maximum of 100 EJ/yr modern bioenergy supply globally
(modern bioenergy used for heat, power, combinations, and
industry was around 18 EJ/yr in 2008)."
(AR5-WG3)

So "limited" means 5.6-fold increase,
whereas 275-300 EJ/y is a 15-17-fold increase over 2008.

100 EJ/y / 9 billion people = 8.5 kWh/d per person

So UK 'share' would be
100 EJ/y × 75 million / (9 billion ) in GW = 26.4 GW
100 EJ/y × 75 million / (9 billion ) / (0.5 W/m2) in km2
= 52 814 km2

2.5 Waleses

100 EJ/y / 6e9 = 12.7 kWh per day per person
100 EJ/y / 7.125e9 = 10.7 kWh per day per person
projected population of UK: 75 million in 2100

100 EJ/y / 9 billion people
2.34 New Jerseys
2.54 Wales

using today's population
((100 (exajoules / year) × 64 million) / 7.125 billion) / (0.5 ((W / m) / m)) =
57000 km2 - nearly 3 Wales

wind: 20-fold increase over 2012 (grey sq = 100 sq km)
nuclear: 4-fold increase over 2012
solar in deserts: 2700 sq km, 2 x Greater London

## How much carbon burial?

10-20 (or 40) Gt CO2 / year

(85 M barrels per day)

"World Oil Production" by Plazak.

after John Shepherd FRS

after John Shepherd FRS

after John Shepherd FRS

after John Shepherd FRS

after John Shepherd FRS

after John Shepherd FRS

The Global Calculator
globalcalculator.org
 UK: 4000 m2 per person 250 people per sq km

Land area of world is 20,000 m2 per person

## Britain

http://www.maps-of-britain.co.uk/

## Things that you might want to do with land area

 Reforestation: 3400 m2 per person would deliver –2 t CO2/y per person Fly (bioenergy): 8300 m2 per person enables one London-LA return per year per person [oilseed rape, today's aviation technology] Drive (bioenergy): 5100 m2 per person enables 17 km per day in a 30 mpg car [oilseed rape, today's technology] Biomass-CCS: 4000 m2 per person enables 16 kWh/d/p of carbon-negative electricity, (–7 t CO2/y/p) assuming sustainable biomass Food: 180 m2 per person 1300 kcal/d of veg 116 m2 per person 2 eggs per day 150-1400 m2 per person 1 pint milk, 50 g cheese per day 450-3500 m2 per person 0.5 lb meat/d (chicken, pork, beef) Not forgetting: nature; recreation; environmental services; buildings; roads

## PV efficiencies

2012 2013 2014 J M Martinez-Duart
"Photovoltaics firmly moving to the terawatt scale"
March 2013

## 'Do it all with solar+storage' - two issues

• Land area required
• Cost of storage
(point size shows land area)
 Ivanpah CA: 377 MW capacity 1079 GWh/y (123 MW)   from 14.2 km2 of land Power per unit area: 8.7 W/m2
 Kagoshima: 70 MW capacity expected load factor 12.8%. 1.04 km2 of land Power per unit area: 8.6 W/m2
 Solana AZ: 280 MW capacity 944 GWh/year (108 MW)   from 12.6 km2 of land Power per unit area: 8.6 W/m2

## Electricity storage costs

 Storage costs - assume $125 per kWh [optimistic?] installed June 2011 — cost$12M ($28 per average watt) Solar system cost:$28k per average kW; (to compete, aiming perhaps for $10k per average kW?) To keep 1 kW going for 12 hours of darkness, need 12 kWh of storage, which costs an extra$1.5k To keep 1 kW going for 5 dull days, need 120 kWh of storage, which costs an extra \$15k So, for PV to deliver cost-competitive reliable electricity in a sometimes-cloudy location, we need two cost breakthroughs!
From "Solar energy in the context of energy use, energy transportation, and energy storage"
by David MacKay (2013)
(NB: assumes that battery, as costed, will last 20 years)

## What pause?

 skepticalscience.com Temperature data, corrected for the ENSO effects Source: Real Climate

# Why climate change action is difficult, and how we can make a difference

## Part 4: Why making good energy policy is difficult

David MacKay FRS

Department of Engineering
University of Cambridge
Department of Energy and Climate Change
United Kingdom Government

## This book is free online

www.withouthotair.com

## Abstract

I will discuss several reasons why climate-change action is difficult.
First, the climate has a long-lasting response to cumulative emissions of carbon. This inconvenient truth implies that it is not enough to cut the emissions rate by some fraction such as 50% or 80%. Climate change will stop increasing only when the net emissions rate is cut to zero; and, equally inconveniently, undoing climate change requires negative emissions.
Second, the public and many decision makers have been misled by myths and wishful thinking about the scale of action required to decarbonize the energy system.
Third, effective climate change action will require the large-scale deployment of low-carbon technologies, most of which are expensive.
We can make a difference by
a) getting involved in innovation and research and development of lower-cost solutions;
b) supporting a numerate approach to energy policy; and
c) supporting the development of open-source energy models for all countries.

7. Making good energy policies is difficult
8. The atmosphere is a commons
9. Solutions must be fair

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