Preface

In 2018, the global energy demand grew by 2.3%, representing a nearly two-fold growth since 2010. This greater energy demand was propelled by a global economy that expanded by 3.7% in 2018. The United States, China, and India together accounted for nearly 75% of the increase in global energy demand. Gas consumption increased 10% from the previous year in the United States alone. The exceptional change in winter and summer seasons was also responsible for a tremendous increase in global energy. Cold snaps drove demand for heating and, more significantly, hotter summer temperatures increased demand for cooling. As a result of greater energy consumption, CO2 emissions also increased to 33.1 Gt, most of which are caused by coal-fired power generation.

Renewables contribute only 25%–30% of the growth in total primary energy demand. This was largely due to an expansion in electricity generation, where renewables accounted for 45% of the growth in 2018. The International Environmental Agency (IEA) set out the Net Zero by 2050 roadmap, according to which the electricity production sector needs to reduce global emissions by nearly three-quarters by 2025. To achieve this, the IEA recommends a more than 6% decrease in electricity generation from coal-fired power plants. Even though renewables installations are expanding quickly, there is not enough to satisfy a strong rebound in global electricity demand. This will result in a sharp rise in the use of fossil fuel electricity generation that risks pushing carbon dioxide emissions.

This book addresses key challenges related to energy production, efficiency evaluation, and CO2 emissions. Section 1 discusses assorted renewable energy generation processes such as wave energy, hydrogen, and low-temperature sources. Section 2 covers efficiency evaluation frameworks, including a standard primary energy framework for efficiency evaluation and process optimization. It also discusses some aspects of industrial energy evaluation and optimization. Section 3 highlights greenhouse gas emissions, energy, and economic and environmental analysis. It also provides detail on energy efficiency technologies to reduce emissions and adverse environmental impacts.

> **Dr. Muhammad Wakil Shahzad** Department of Mechanical and Construction Engineering, Northumbria University,

> > **Muhammad Sultan** Bahauddin Zakariya University, Multan, Pakistan

**Laurent Dala and Ben Bin Xu** Northumbria University, Newcastle upon Tyne, United Kingdom

Newcastle upon Tyne, United Kingdom

**Yinzhu Jiang** Zhejiang University, Hangzhou, China
