Solar Farms

The Earthscan Expert Guide to Design and Construction of Utility-scale Photovoltaic Systems

Susan Neill, Geoff Stapleton, Christopher Martell, Frank Jackson

• Editorial: Routledge
• Año: 2017
• ISBN:
  9781317308737
• Edición: 1
• Categoría: Biological Sciences
• Categoría: Ecology

The market and policy impetus to install increasingly utility-scale solar systems, or solar farms (sometimes known as solar parks or ranches), has seen products and applications develop ahead of the collective industry knowledge and experience. Recently however, the market has matured and investment opportunites for utility-scale solar farms or parks as part of renewable energy policies have made the sector more attractive. This book brings together the latest technical, practical and financial information available to provide an essential guide to solar farms, from design and planning to installation and maintenance.

The book builds on the challenges and lessons learned from existing solar farms, that have been developed across the world, including in Europe, the USA, Australia, China and India. Topics covered include system design, system layout, international installation standards, operation and maintenance, grid penetration, planning applications, and skills required for installation, operation and maintenance. Highly illustrated in full colour, the book provides an essential practical guide for all industry professionals involved in or contemplating utility-scale, grid-connected solar systems.

1
Introduction

Background

Context

In modern society, electricity is considered a fundamental public commodity as it is used in almost every aspect of life (see Figure 1.1). Electricity is essential for human well-being, and plays a key role in promoting social development and economic growth. However, growing electricity demand in the modern and developing world, coupled with the looming danger of climate change, means that it is becoming more and more imperative for cleaner renewable energy technologies to replace traditional fossil-fuelled generators.

Figure 1.1 Uses of electricity in our daily lives.

Source: Global Sustainable Energy Solutions

In response to the threat of climate change, many countries around the world have committed to reduce greenhouse gas (GHG) emissions through the implementation of renewable energy targets, emissions reduction plans, carbon pricing, etc. This commitment, coupled with reduction in the price of photovoltaic modules, is driving investment in solar photovoltaic (PV) technologies. There are currently 164 countries (up from 43 countries in 2005) with a stated renewable energy target; the majority of these are countries with developing and emerging economies (IRENA 2015). Analysis has shown that in order to keep the global temperature rise within safe limits, renewable energy must account for 36% or more of global electricity generation by 2030, requiring USD 550 billion in annual investment (IRENA 2014). As a result of the 2015 Conference of Parties (COP21) in Paris, 195 countries have agreed to keep warming below 1.5–2°C above pre-industrial levels to reduce the risks and impacts of climate change. One hundred and eighty six of these countries have pledged to reduce GHG emissions through aggressive renewable energy targets, and will be reviewed and monitored in five-year cycles.

Demand

Electricity demand has increased steadily since the Industrial Revolution and is expected to continue growing over coming decades (see Figure 1.2). While countries such as those in the European Union, the United States and Japan are expected to reduce overall demand by 2040, other countries, particularly China and India, are expected to grow quite significantly.

This continuing growth in demand calls for aggressive action in order to keep atmospheric CO₂ within internationally agreed levels. With pledges from almost every country around the world committing to take real action on climate change, Figure 1.3 shows that renewable energy technologies are expected to make up the majority of the generation mix worldwide by 2040.

Although electricity demand is on the rise, there are still approximately 1.1 billion people without access to electricity, most of whom are concentrated in Africa and Asia. In addition to that, there are still 2.9 billion people (840 million people in India and about 450 million people in China) that rely on wood or other types of biomass for cooking and heating, which is causing about 4.3 million premature deaths from indoor air pollution each year (The World Bank Group 2015). Clean renewable energy technologies like solar PV can play a key role in improving electricity access to remote communities in these areas. The International Energy Agency predicts that the number of people without access to electricity will decline to around 810 million in 2030 and 550 million in 2040 which will be about 6% of the global population at that time (IEA 2015). As more and more parts of the world have access to electricity, the utility-scale solar market is likely to follow and therefore utility-scale solar is expected to make up a larger portion of the world's electricity generation mix.

Figure 1.2 Expected change in energy demand in selected regions (2014–40).

Source: OECD/IEA

Figure 1.3 Current and projected global electricity generation by source.

Source: OECD/IEA

PV applications

Solar PV technology enables electricity to be generated directly from sunlight. Electric power can be generated using large solar farms (centralised grid-connected) or by solar installations on buildings (decentralised grid-connected), as well as at locations not connected to utility grids (off-grid applications). A breakdown of the global market share for each of these applications is given in Figure 1.4.

Figure 1.4 Global market share of off-grid, decentralised grid-connected and centralised grid-connected PV systems.

Source: IEA PVPS

Centralised grid-connected systems

Centralised grid-connected systems are large-scale PV systems, also known as solar farms. The definition of a solar farm varies, based on its scale, the mounting structure, type of grid connection, etc., and may be known as a solar park, solar plant, utility-scale solar system, etc. depending on where you are. These systems are typically ground mounted and are built to supply bulk power to the electricity grid like any other centralised power station. For this publication, a solar farm is defined as a ground-mounted, centralised, grid-connected PV system of the scale 10 MWp or above. Looking at Figure 1.4, utility-scale systems made up a very insignificant portion of global market share of PV systems since up until 2007, and has rapidly grown since; now making up a larger share than decentralised PV systems. Declining costs of PV technology, coupled with government policies targeting large scale renewable energy, have allowed utility-scale solar to become more and more competitive with other forms of decentralised electricity generation, driving rapid deployment in many countries across the globe.

Due to the large scale of these solar systems, the processes involved in developing these projects are far more complex and rigorous than that for smaller, decentralised PV systems. Successful projects require high capital investments, expertise in many areas, thorough planning, careful design, consultation with many stakeholders and ongoing maintenance.

Figure 1.5 105.56MW Perovo Solar Park (Crimea, Russia).

Source: Activ Solar

With the help of policy support in the form of renewable energy targets, deployment of solar farms worldwide is increasing at a faster rate than information and training specific to these larger-scale systems is being made available. This book aims to provide relevant and thorough information on the planning, design, construction, commissioning, operation and maintenance of utility-scale solar systems.

Decentralised grid-connected PV systems

Decentralised grid-connected PV systems may be installed to meet a residential, commercial or industrial requirement (typically on rooftops). These systems generate electricity that is either consumed in the building or sold onto the grid – with price determined by policymakers or utilities. These systems can be installed as a cost-effective option to users who consume energy during the day, with the excess generation able to be sold to the grid. Decentralised grid-connected PV systems made up the bulk of the global markets share of PV systems until 2013, when centralised systems overtook them.

Off-grid PV systems

Off-grid PV systems can be used for domestic applications to provide electricity (lighting, refrigeration, etc.) to households that are not connected to the utility grid; or for non-domestic applications to provide electricity for commercial application in remote areas for things like telecommunications, water pumping, vaccine refrigeration and navigation. Off-grid PV systems are usually installed in remote areas where connection to the grid is either not possible, or very expensive. While the market share of off-grid systems is tiny compared to grid-connected systems (see Fi...