Floating PV Plants

Marco Rosa-Clot, Giuseppe Marco Tina, Marco Rosa-Clot, Giuseppe Marco Tina

• Publisher: Academic Press
• Year: 2020
• ISBN:
  9780128170625
• Topic: Physical Sciences
• Subtopic: Energy

Renewable energy sources (RES) are one of the important instruments that human beings can use to tackle problems created by climate change. We expect a quick expansion of RES in the next few years.

One important new technology is the floating photovoltaic (FPV) which is at its very beginning but which after only 10 years from its first proposal has already reached the target of 2 GWp of plants installed.

This book explores the reasons for such growth and the advantages of this new technology. FPV plants are easily integrated into any human settlements and can use available fresh water as well as salt water near coastal areas. So their geographic potential is unlimited.

Furthermore, their environmental impact is limited and the managing and decommissioning of plants are very cheap.

The book offers a perspective on the many facets of this technology as well as an analysis of the economic aspect and of the final electricity cost which in a short time will go down to less than 50 $ per MWh.

Contributions from different authors have helped in sectors such as the raft structure, the wave impact, and the environment problems.

• Investigates the installation of photovoltaic systems over the water's surface
• Offers theoretical and practical explanations on how to study, analyze and design photovoltaic energy systems
• Considers how the use of floating photovoltaic systems can work to fulfill domestic energy demand

Chapter 1

Introduction

Marco Rosa-Clot, and Giuseppe Marco Tina

Abstract

Status of renewable energy sources is reviewed at a worldwide level. Penetration and advantages of floating photovoltaic plants are discussed. List of book contents is discussed.

Keywords

Floating PV (FPV) plants; Renewable energy sources (RESs)

1. Renewable Energy Sources: Why Floating PV Plants?

Renewable energy sources (RESs) have been strongly increasing in the last decade with an overwhelming importance in the electricity sector. The electric sector represented 43% of energy demands in 2017, and this percentage will rise to 47% in the next 20 years [1]. At the same time, global warming and climate changes are the new challenges for mankind, and this crisis is mainly due to the burning of fossil fuels.

Globally RESs have registered an 8% yearly increase in the installed power in the last 10 years [1]. This increase is being driven by the sensational development of the photovoltaic (PV) sector which has registered a rate of growth of 45% and also by the wind sector (19%) with a more rapid growth for the offshore plants (33%).

The exponential growth of PV sector is slowing down, and if we compare the last decade we get Table 1.1 [2], where the yearly increase for the different RESs are given for the last two periods of 5 years.

It is quite evident that the rush of the PV sector is continuing because PV plants are simple, cheap, and easily and quickly installed. This increase is shown in synthesis in Fig. 1.1, where the four main components (hydroelectric, wind, photovoltaic, and biomass) are given. See Ref. [3] for the data.

However, the hydroelectric sector is even more important than what appears from Fig. 1.1 if we consider the electric energy production. Its contribution is more than 4 million GWh in 2017, that is, 73% of the energy produced by RES compared with the installed power which is only 58%. This is due to the very high capacity factor of hydroelectric plants.

Currently, the MWh produced in a year for any MW installed (capacity factor: CF usually given in hours) is on average 3294 MWh/year for any hydroelectric MW installed, and this value should be compared with solar PV (1146 hours) and wind farm (2183 hours); the only more efficient technology is the production with biomass which reaches 4635 hours and geothermal with 6326 hours. See Fig. 1.2.

Therefore, if we look to the renewable energy sector, even if the solar PV is quickly increasing and in 2017 it covered 17.7% of the renewable energy power, its contribution to the energy production is only 5%. In contrast, bioenergy which covers only 5% of the installed electric power reached 8.6% of the energy production, thanks to the large CF value. A plot is given in Fig. 1.3, where the large hydroelectric production has been omitted (4185 TWh in 2017) in order to highlight the new emerging technologies.

Notwithstanding the limited CF factor, PV is still expanding for several reasons:

1. • Simplicity and reliability
2. • Scalability
3. • Low costs
4. • Availability worldwide even near human settlement with limited environmental impact

There are, however, two main limits in the use of PV power source: the land use and the lack of incentives:

1. • Land use: The requirement for a large surface of land due to low PV panel efficiency (typically around 14%), this implies that a 1 MWp power station requires at least 15,000 m² of land, and this has a large environmental impact since the land cannot then be used for other purposes (agriculture, pasture, etc.).
2. • Incentives: The photovoltaic market was doped by very high incentives values. These were necessary for the start-up of the PV sector, but made the customers to use large land areas, which could have been exploited for other economic purposes. Since 2011, the incentives began to disappear at global level and, as a consequence, the PV market suffered a slowdown and the PV had to face the competition of other energy sources [1] (Fig. 1.4).

The effects of these two factors combined led to the contraction of the PV market in Europe and North America.

The lack of incentives has been partially overcome by the dumping of the PV modules, but the land disposal remains an important limit, especially in industrialized countries.

Table 1.1

Yearly Growth Rate for the Period 2007–12 and 2012–17.

	Rate of Growth	Rate of Growth
	5 years 2007–12	5 years 2012–17
Technology
Total renewable energy	7.7%	8.6%
Renewable hydropower	3.4%	3.2%
Wind	23.8%	14.0%
Solar photovoltaic	61.9%	31.7%
Bioenergy	9.1%	6.9%

The wind energy sector has partially solved the problem of land occupancy. The production of huge wind turbines triggered a ...