What Colour is your Building?

Measuring and reducing the energy and carbon footprint of buildings

David Clark

• Publisher: RIBA Publishing
• Year: 2019
• ISBN:
  9781000706796
• Edition: 1
• Topic: Architecture
• Subtopic: Architecture General

Defining and reducing the carbon footprint of a new or refurbished building can be a daunting task. There are lots of tools to measure the environmental impact of buildings, but they all measure energy and CO2 in different ways, and they do not measure the whole carbon footprint.

What Colour is your Building? provides practical and pragmatic guidance on how to calculate and then compare the whole carbon footprint of buildings using one simple method looking at operating, embodied and transport energy. It will equip designers, building owners, occupiers, planners and policy makers with the tools and knowledge that they will need to make decisions early on about where the big impacts will be in terms of reducing the carbon footprint of the building, including:

• A new, simple approach to understanding the whole carbon impact of buildings
• Benchmarking data for operating energy performance
• A clear, transparent method of separating landlord energy performance from tenant energy performance
• Simple diagrams and numbers to put renewable energy into perspective.

Part 1
What Colour?

Measuring energy and carbon in buildings

Chapter One
Energy and carbon in buildings

The world has achieved brilliance without wisdom, power without conscience. Ours is a world of nuclear giants and ethical infants … If we continue to develop our technology without wisdom or prudence, our servant may prove to be our executioner.

General Omar Bradley
An Armistice Day Address (10 November 1948), published in The Collected Writings Of General Omar N. Bradley, Volume 1 (1967)

1.1 The Global Energy Challenge

Rising energy consumption

Global energy consumption is a function of three factors: the number of consumers (people), their demand for services (expectations) and the efficiency with which the services are provided (efficiency). A pseudo equation for this, which applies at building, city and global scales, is:

The global population is predicted to increase by 25% over the next two decades, from 6.9 billion in 2010 to 8.6 billion in 2035, with nearly all this growth occurring in the urban areas of developing countries.¹ More people means more energy consumption. At the same time, people’s incomes in developing countries are rising, leading to further demands for energy as their expectations increase. The high-income Western lifestyle consumes a lot of energy (cars, large TVs, numerous gadgets, big fridges, air conditioning, flights overseas, comfortable houses and so on) and people in other countries want some of this too.

In high-income countries the average energy consumption in 2010 was 159 kWh per person per day (kWh/p/d), in lower middle income countries it was only 21 kWh/p/d and the world average was 59 kWh/p/d.² In just 10 years since 2000, China’s consumption almost doubled from 30 kWh/p/d to 58 kWh/p/d. This is still half the per capita energy consumption of the UK and less than one-quarter of the USA’s. What will happen when billions more people double their energy consumption?

The final factor is efficiency. History suggests, somewhat counter-intuitively, that as we improve energy efficiency, rather than reducing energy consumption it offen goes up. For example, as cars became more efficient we could afford to drive further, and efficient gas central heating allows all rooms to be heated to higher temperatures for longer periods rather than using a single gas fire to heat one or two rooms. This effect is known as the Jevons Paradox.³ To counter it, as efficiency increases then the cost of energy also needs to rise so that the net cost to the consumer of using the product or service remains the same while energy consumption reduces. Will this be politically palatable?

Reducing the global demand for energy is therefore a huge challenge. Between 2010 and 2035 it is predicted that energy consumption will increase by one-third, and that is assuming governments actually implement their current energy and climate policies (rather than just talking about them).⁴ Buildings account for around 40% of global energy consumption⁵ and will therefore have to be a major part of the energy solution.

Reliance on fossil fuels

Coal accounted for nearly half of the 25% increase in global energy use between 2000 and 2010, with the bulk of the growth coming from the power sector in emerging economies. Over 80% of the demand for energy in 2010 was supplied from fossil fuels and current predictions suggest that it will still account for 75% in 2035.⁶

Fossil fuels are a finite resource – it’s just that no one can agree on how much there is remaining, how long it will last and what the cost to consumers will be. While oil supply diversity is diminishing, new technologies are opening up previously unviable reserves, such as shale gas. The Deepwater Horizon oil spill disaster in the Gulf of Mexico in 2010 and the groundwater pollution concerns raised by the fracking techniques used to extract shale gas are reminders that extracting fossil fuels is not without economic, social and environmental risk.⁷

The significant changes in lifestyle and economic prosperity that have occurred in the 250 years since the Industrial Revolution, have been built on fossil fuels. It is going to be very difficult to wean the world off this resource. While fossil fuels will not run out in the next 50 years, new reserves of fossil fuels that are cheap and easy to extract are becoming harder to find. This, combined with increasing consumption, will lead to more competition for energy, which will result in higher energy prices.

Energy and other Environmental Issues

In addition to greenhouse gas emissions, other impacts associated with the use of energy include air pollution, water pollution, loss of biodiversity and habitat, visual or noise pollution and deforestation. These issues are not limited to fossil fuels: wind turbines are visually obtrusive, biomass releases particulates, plantations for biofuel can cause deforestation or replacement of food crops, hydro schemes can lead to major relocation of people and flooding of habitat, and nuclear power has issues related to fallout and the safe storage of radioactive waste for thousands of years. Most energy sources have localised environmental or social impacts – the problem with fossil fuels is that their climate change impact is also global.

Security of supply

Securing a reliable and diverse energy supply in the future is now a major concern in many countries. The European Union’s Climate and Energy Policy states that the EU needs more secure energy sources, and to be less dependent on imports of foreign oil and gas, so as to make it less vulnerable to volatile energy prices and uncertain supply chains.⁸ The EU currently imports over half of its primary energy requirements and is wary of an overreliance on Russia to supply natural gas.⁹ Between 2002 and 2009, the renewable sector grew by over 50% and currently accounts for around one-fiffh of the EU’s primary energy production, with the majority from biomass and waste.

The increased use of air conditioning, heat pumps, computers and, more recently, electric vehicles is increasing the demand for electricity. To provide a reliable supply of electricity requires significant investment in power stations and distribution infrastructure, but even with this, unexpected events can lead to power shortages. Should we be designing buildings that require a constant supply of grid electricity to remain habitable?

CO₂ and global warming

When fuel is converted into energy to power buildings, industry and transportation it releases greenhouse gases (GHG). The amount of GHG emitted depends on the type of fuel used.¹⁰

GHG emissions = energy x carbon content of fuel

The radiative forcing of the climate system, which causes global warming, is dominated by increasing...