Power Generating
Content
2011
Power Generating
Using renewable sources for generating Electricity
This is a overlook at the ability to use renewable energy sources to generate power to use in Sri Lanka. Especially as we are living in an island, using the energy of the waves might work handy for us…
Nipuna Lakmal Weerakkody – 100573 H
Faculty of Engineering – University of Moratuwa 3/15/2011
Introduction
As I am interested in the field of electricity, I thought that I might do this project on generating power using renewable sources of power (Question no 1 of the given assignment). Though it is not very feasible to a country like us, the trend in the world scenario is very much different to that here in our country. People and investors try their best to promote these kinds of energy generating methods, specially using wave energy from our sea.
W. Nipuna Lakmal Weerakkody 100573H Faculty of Engineering University of Moratuwa
2
Table of Contents
Title Introduction Table of Contents Wave and Tidal Energy Oscillating Water Column (OWC) The Pivoting Flap Device Tapered Channel Devices The Pelamis Buoyant Moored Device Tidal Turbines Wave Height Samples from Around the World An article taken from the internet Page Number 2 3 4 4 5 5 6 6 7 8 11
3
Using Waves for Energy Generating
Wave and Tidal Energy Wave and tidal energy harvesting has been around for a few decades. But it has only been in recent years that it has started to become more realistic due to advance in research and technology. It is said that wave and tidal energy can supply at least 10 percent of the world's energy consumption. How much power can be harvested is determined mainly on the wave activity. A map of wave heights is shown towards the end of the document. Examples of Wave Energy Devices The following are examples of devices that have been invented to harvest energy from waves and sea currents. They do not represent a complete list but they are divided into three main categories: on shore, off shore, and near shore. Each type has its own benefits and drawbacks covering issues such as efficiency, cost per Watt, environmental and social impact. Oscillating Water Column (OWC) This method uses waves to compress air in a closed chamber to generate wind which flows through a turbine. Wind is created both when the wave proceeds and recedes from the chamber. A special turbine is designed to spin in one direction regardless of the wind direction. This significantly increases the efficiency of the power generation process.
4
LIMPET is a prototype constructed in 2000 on the west coast of the Scottish island of Islay. It was capable of generating 500 kWatts, which is about 1/12 of the island's total power consumption.
The Pivoting Flap Device This device also creates a chamber for waves to push water in and out. It has a flap at the entrance which pivots back and forth as the wave enters and exits the chamber. This motion drives a hydraulic pump which drives the generator.
5
Tapered Channel Devices This method uses the wave to pump sea water to an elevated reservoir. The trapped water can then be released back through a turbine generating electricity. The system in the image below is being tested in Trinidad California.
The Pelamis This method works by creating a multi-segment floating tube anchored to the sea floor. The joints between each segment can move as the structure is hit by the waves. This motion is converted into energy through hydraulic cylinders which drives a hydraulic motor.
A company in Scotland named Ocean Power Delivery Ltd has created a pelamis that is 130m long and 2.3m in diameter. It is expected to generate 750 kWatts.
6
Buoyant Moored Device This method creates motion by resisting the waves. One part of the system needs to be moored (anchored) to the sea floor while a second part moves as it resists the wave motion. Blow is an image of a system called the Duck created by Professor Salter at Edinburgh University. The base of the duck is moored to the sea floor while the duck itself (red) rotates with the wave motion. This rotation is used to generate energy.
Tidal Turbines This method works much the same way as wind turbines. However, since water is four times denser than air, the tidal turbine can be much smaller to generate the same amount of energy. The ideal water current is between 2-2.5 m/s, which is usually at depths of 20-30m within 1 km from the shore. A commercial scale turbine can produce 300 kWatts but this can scale up depending on the farm's size.
7
The image below shows "Seaflow," the world's first experimental tidal turbine. It is deployed in 2003 off the shore of Devon UK. It can produce 300 kWatts.
Wave Height Samples from Around the World The following shows a snapshot of wave height from around the world. Although the weather and other factors can influence the measurements, the maps show a rough idea of wave activities expected in each region.
8
The world
Source: OCEANOGRAPHIE SPATIALE
9
South East Asia
Source: National Environment http://intranet.mssinet.gov.sg/marine/options.html South Atlantic
Agency
of
Singapore
Source: Fleet Numerical Meteorology and Oceanography Center
10
Wave Energy Wave Energy Conversion refers to the capture of ocean wave energy to do useful work including electricity generation, desalination, and pumping of water. Sea and Ocean waves are considered by most experts to be one of the best options for the future production of renewable energy, together with photovoltaic (PV) energy. Scientists and inventors have been trying to figure out ways to capture the energy in ocean waves for decades, without much success. There have been hundreds of patents taken out over the years. The current frenzy in development is similar to what happened at the beginning of human flight, when many solutions were tried before the correct one was found. DISTRIBUTED RENEWABLE ENERGY GENERATION In principle, Wave Energy is the ideal choice for distributed generation of energy: a large majority of the world population lives near reasonably energetic seas. Distributed generation by renewable sources has many advantages over centralized generation, not only because you save on grid infrastructure, but also because each community can be responsible for Operations and Maintenance of their renewable energy sources. In many cases production of water via desalination allows for de facto storage of excess energy in the form of purified water, thus saving a huge amount of money which would be needed to upgrade the grid to a smart grid capable of handling the fluctuations of renewable energy sources. Moreover, this makes cheap and renewable energy immediately available also to more isolated communities which otherwise would have to wait for the smart grid to reach them. Seabased AB and Fortum are going to construct the world’s largest wave power plant. This is a renewable source of energy, which will provide customer, society as well as other stakeholders with reliable energy. The Sweden Energy Agency is supporting this mega project with a grant. It was only today, that the full financial support to construct wave power plants at the coast of Smögen in Sotenäs, Sweden was made public. The total sum that Swedish Energy Agency is providing is SEK 139, 000, 000 of a total of SEK 250, 000, 000. This project is going to be the hugest of its sort in the world. The Seabased industry technology will be made fully commercialized, both demonstrating and showing the capacity of the technology. The plant will be constituted of around 400 to 500 units linked together. The capacity will be of around 10 MW. The Swedish Government supports the growth of renewable energy, thereby encouraging Swedish Energy Agency to finance new technologies and making them commercially suitable. There has been another four projects that have been offered grants and this is the fifth and last one for the actual program according to a report submitted May, 2009. There have been endless research and analysis performed by all the three institutions (Fortum/Sea-based and Swedish Energy Agency) before the project was fully approved. Yet, there is still another permission that needs to be achieved. The Swedish Environmental Authority and the European Unions will have to give their accreditations for construction to take-off. This is a particular technology that Sea-based AB is commercializing. They confirm that wave energy is a lucrative alternative source for energy. The potential are endless knowing that the earth surface is mostly covered by oceans
11
-
The following article was taken from internet -
Ocean Renewable Energy Has Huge Potential But Not Without Giant Hurdles
Since 1844, when the first tide wheel was built, inventors have been trying to harness the immense power of the ocean with little success. Now the next generation of engineers is trying to break the course of history and turn this niche industry into a major energy player. "Show me the energy...Not a lot of these devices are actually generating electricity today." Rob Cinq Mars, President, Free Flow Energy. In 1894, currents were used to compress air and run a turbine; today, waves are being used to compress air in an oscillating water column. In 1923, a patent was issued for a snake-like machine that used waves to run a hydraulic pump; today,Pelamis Wave Power has deployed (and since removed) an almost-identical machine off the coast of Portugal. And in 1946, a horizontal-axis turbine was invented to harness the currents of the ocean; today, Verdant Power is testing a similar device in the East River near New York City. “Many people think this industry is new, but these devices have been around for a long time. You see a lot of the newer designs that are based on older designs,” says Rob Cinq Mars, President of the engineering consultancy Free Flow Energy . The marine energy industry is generally broken up into a number of different technologies: wave, tidal, current, salinity gradient, ocean thermal and offshore wind. Offshore wind — while still very nascent — is one of the only technologies being deployed on a commercial scale.
12
There's a lot of excitement about wave and tidal technologies today — a result of the broader interest in clean energy. But Cinq Mars is cautious about some of the claims being made by companies. Many tout the benefits of their technologies, but few are actually close to achieving those claims. “Show me the energy,” he says. “Not a lot of these devices are actually generating electricity today.” The small bits of electricity actually being generated usually come in at the US $0.40 per kilowatt-hour (kWh) range.
Technological successes in marine energy over the last 165 years have been incremental. But with the emergence of new materials, sophisticated electronics and unprecedented amounts of money being invested in new ocean energy technologies, the industry is looking far different than it did in the past. In fact, says Richard Meyer, President of the Ocean Energy Council , it has changed more in the last few years than it has over the last century. “Two or three years ago...it was really only small laboratory testing of devices. These days they've got things in the water, they've got sites selected and they're worrying about regulations. Things have really come a long way in a short time,” says Meyer. Today’s marine renewable energy industry is commonly compared to the wind industry of the 1980's and early 1990's. At that time, there were many competing technologies being developed and thousands of turbines were broken during the testing process, says Meyer. Eventually, certain designs won out, parts for those machines were standardized, and a supply chain was created to service them. The marine energy industry will have to go through the same culling process. “We won't break thousands [of turbines] but it may be a lot before we get somewhere. Ocean energy is about 15 years behind wind energy, but it won't tak- 15 years to catch up,” he says. With only 10 megawatts of installed marine energy capacity around the world, the industry has a long way to go before it catches up with the more than 120 gigawatts of global wind capacity. In theory, the oceans could supply us with a lot of energy. The International Energy Agency estimates that tidal, wave, current, salinity gradient and ocean thermal technologies could represent more than 100,000 terawatt-hours of energy each year. There remain a number of difficulties that companies must face in order to bring the industry to this scale. The high cost of demonstrating projects remains a significant problem, especially recently because of the lack of capital available due to the financial crisis. As later stage companies
13
get further along in the testing process, cash-burn rates accelerate and the need for capital increases. But many investors are hesitant to touch risky, unproven technologies.
Firms like Ocean Renewable Power Company (ORPC) know a lot about the financial difficulties of later-stage testing. ORPC has been developing its cross-flow turbine for ocean and river currents since 2004. Last fall, it tested a 30-kilowatt (kW) pilot version in the Bay of Fundy off the coast of Maine. Bad weather, broken measurement instruments and incorrectly sized turbine foils were some of the setbacks the team experienced, says ORPC President Chris Sauer. When the company starts testing its 60-kW pre-commercial unit this fall, those setbacks will be much more expensive. “We are in this for the long haul...we knew that we needed to find a really strong, strategic partner that has some financial strength,” says Sauer. Like many other companies, ORPC was unable to raise any private equity after the financial markets broke down last fall. However, Sauer says that the company has teamed up with a strategic partner that will get it through the next testing phase and allow it to demonstrate the commercial viability of its turbine by the end of the year. ORPC has not yet released any details of the partnership. Some companies haven't been as lucky. Pelamis Wave Power, which developed the first commercial-scale wave project off the coast of Portugal, is now trying to find a new investor. It's primary partner, Babcock and Brown, went bankrupt in March. In the meantime, the Pelamis devices are sitting idle while the company tries to find the money to fix them. Another leading developer, Finavera Renewables , announced in February that it would temporarily abandon the wave energy business in order to focus on wind. That announcement came more than a year after its device sank off the coast of Oregon . Finavera says it will try to bring in new partners for future development of the AquaBuOY technology. As if these short term testing problems weren't difficult enough, understanding the long-term viability of these devices is even more uncertain. None of them have been in the treacherous sea environment for very long. “Everyone agrees that survivability is the key technology challenge,” says John Miller, Director of the New England Marine Renewable Energy Center . “I think in the past, there wasn't a full appreciation for the challenges involved. Now there is.” Once technologies are ready to be deployed on a commercial or pre-commercial scale, a long and complex permitting process must be completed. This process can also be a problem for inexperienced, cash-strapped companies — especially in the U.S. where the layers of local, state and federal regulations can be difficult to navigate.
14
These demanding financial, technological and regulatory requirements will eventually weed out the weak companies and bring the companies with the best technology and project management skills to the top. “You have to be able to do it all. If you want to be successful in this industry, you need to understand the whole package of project development,” says ORPC's Sauer. “This is not just about a technology.” A number of players have entered the market without recognizing the scope of the challenges, he says. “I do think in marine renewables, the euphoria has subsided a bit. People realize now what we realized a long time ago — that this is not an overnight thing. It takes hard work and it takes hard work over a long period of time,” says Sauer.
15
Power Generating
Using renewable sources for generating Electricity
This is a overlook at the ability to use renewable energy sources to generate power to use in Sri Lanka. Especially as we are living in an island, using the energy of the waves might work handy for us…
Nipuna Lakmal Weerakkody – 100573 H
Faculty of Engineering – University of Moratuwa 3/15/2011
Introduction
As I am interested in the field of electricity, I thought that I might do this project on generating power using renewable sources of power (Question no 1 of the given assignment). Though it is not very feasible to a country like us, the trend in the world scenario is very much different to that here in our country. People and investors try their best to promote these kinds of energy generating methods, specially using wave energy from our sea.
W. Nipuna Lakmal Weerakkody 100573H Faculty of Engineering University of Moratuwa
2
Table of Contents
Title Introduction Table of Contents Wave and Tidal Energy Oscillating Water Column (OWC) The Pivoting Flap Device Tapered Channel Devices The Pelamis Buoyant Moored Device Tidal Turbines Wave Height Samples from Around the World An article taken from the internet Page Number 2 3 4 4 5 5 6 6 7 8 11
3
Using Waves for Energy Generating
Wave and Tidal Energy Wave and tidal energy harvesting has been around for a few decades. But it has only been in recent years that it has started to become more realistic due to advance in research and technology. It is said that wave and tidal energy can supply at least 10 percent of the world's energy consumption. How much power can be harvested is determined mainly on the wave activity. A map of wave heights is shown towards the end of the document. Examples of Wave Energy Devices The following are examples of devices that have been invented to harvest energy from waves and sea currents. They do not represent a complete list but they are divided into three main categories: on shore, off shore, and near shore. Each type has its own benefits and drawbacks covering issues such as efficiency, cost per Watt, environmental and social impact. Oscillating Water Column (OWC) This method uses waves to compress air in a closed chamber to generate wind which flows through a turbine. Wind is created both when the wave proceeds and recedes from the chamber. A special turbine is designed to spin in one direction regardless of the wind direction. This significantly increases the efficiency of the power generation process.
4
LIMPET is a prototype constructed in 2000 on the west coast of the Scottish island of Islay. It was capable of generating 500 kWatts, which is about 1/12 of the island's total power consumption.
The Pivoting Flap Device This device also creates a chamber for waves to push water in and out. It has a flap at the entrance which pivots back and forth as the wave enters and exits the chamber. This motion drives a hydraulic pump which drives the generator.
5
Tapered Channel Devices This method uses the wave to pump sea water to an elevated reservoir. The trapped water can then be released back through a turbine generating electricity. The system in the image below is being tested in Trinidad California.
The Pelamis This method works by creating a multi-segment floating tube anchored to the sea floor. The joints between each segment can move as the structure is hit by the waves. This motion is converted into energy through hydraulic cylinders which drives a hydraulic motor.
A company in Scotland named Ocean Power Delivery Ltd has created a pelamis that is 130m long and 2.3m in diameter. It is expected to generate 750 kWatts.
6
Buoyant Moored Device This method creates motion by resisting the waves. One part of the system needs to be moored (anchored) to the sea floor while a second part moves as it resists the wave motion. Blow is an image of a system called the Duck created by Professor Salter at Edinburgh University. The base of the duck is moored to the sea floor while the duck itself (red) rotates with the wave motion. This rotation is used to generate energy.
Tidal Turbines This method works much the same way as wind turbines. However, since water is four times denser than air, the tidal turbine can be much smaller to generate the same amount of energy. The ideal water current is between 2-2.5 m/s, which is usually at depths of 20-30m within 1 km from the shore. A commercial scale turbine can produce 300 kWatts but this can scale up depending on the farm's size.
7
The image below shows "Seaflow," the world's first experimental tidal turbine. It is deployed in 2003 off the shore of Devon UK. It can produce 300 kWatts.
Wave Height Samples from Around the World The following shows a snapshot of wave height from around the world. Although the weather and other factors can influence the measurements, the maps show a rough idea of wave activities expected in each region.
8
The world
Source: OCEANOGRAPHIE SPATIALE
9
South East Asia
Source: National Environment http://intranet.mssinet.gov.sg/marine/options.html South Atlantic
Agency
of
Singapore
Source: Fleet Numerical Meteorology and Oceanography Center
10
Wave Energy Wave Energy Conversion refers to the capture of ocean wave energy to do useful work including electricity generation, desalination, and pumping of water. Sea and Ocean waves are considered by most experts to be one of the best options for the future production of renewable energy, together with photovoltaic (PV) energy. Scientists and inventors have been trying to figure out ways to capture the energy in ocean waves for decades, without much success. There have been hundreds of patents taken out over the years. The current frenzy in development is similar to what happened at the beginning of human flight, when many solutions were tried before the correct one was found. DISTRIBUTED RENEWABLE ENERGY GENERATION In principle, Wave Energy is the ideal choice for distributed generation of energy: a large majority of the world population lives near reasonably energetic seas. Distributed generation by renewable sources has many advantages over centralized generation, not only because you save on grid infrastructure, but also because each community can be responsible for Operations and Maintenance of their renewable energy sources. In many cases production of water via desalination allows for de facto storage of excess energy in the form of purified water, thus saving a huge amount of money which would be needed to upgrade the grid to a smart grid capable of handling the fluctuations of renewable energy sources. Moreover, this makes cheap and renewable energy immediately available also to more isolated communities which otherwise would have to wait for the smart grid to reach them. Seabased AB and Fortum are going to construct the world’s largest wave power plant. This is a renewable source of energy, which will provide customer, society as well as other stakeholders with reliable energy. The Sweden Energy Agency is supporting this mega project with a grant. It was only today, that the full financial support to construct wave power plants at the coast of Smögen in Sotenäs, Sweden was made public. The total sum that Swedish Energy Agency is providing is SEK 139, 000, 000 of a total of SEK 250, 000, 000. This project is going to be the hugest of its sort in the world. The Seabased industry technology will be made fully commercialized, both demonstrating and showing the capacity of the technology. The plant will be constituted of around 400 to 500 units linked together. The capacity will be of around 10 MW. The Swedish Government supports the growth of renewable energy, thereby encouraging Swedish Energy Agency to finance new technologies and making them commercially suitable. There has been another four projects that have been offered grants and this is the fifth and last one for the actual program according to a report submitted May, 2009. There have been endless research and analysis performed by all the three institutions (Fortum/Sea-based and Swedish Energy Agency) before the project was fully approved. Yet, there is still another permission that needs to be achieved. The Swedish Environmental Authority and the European Unions will have to give their accreditations for construction to take-off. This is a particular technology that Sea-based AB is commercializing. They confirm that wave energy is a lucrative alternative source for energy. The potential are endless knowing that the earth surface is mostly covered by oceans
11
-
The following article was taken from internet -
Ocean Renewable Energy Has Huge Potential But Not Without Giant Hurdles
Since 1844, when the first tide wheel was built, inventors have been trying to harness the immense power of the ocean with little success. Now the next generation of engineers is trying to break the course of history and turn this niche industry into a major energy player. "Show me the energy...Not a lot of these devices are actually generating electricity today." Rob Cinq Mars, President, Free Flow Energy. In 1894, currents were used to compress air and run a turbine; today, waves are being used to compress air in an oscillating water column. In 1923, a patent was issued for a snake-like machine that used waves to run a hydraulic pump; today,Pelamis Wave Power has deployed (and since removed) an almost-identical machine off the coast of Portugal. And in 1946, a horizontal-axis turbine was invented to harness the currents of the ocean; today, Verdant Power is testing a similar device in the East River near New York City. “Many people think this industry is new, but these devices have been around for a long time. You see a lot of the newer designs that are based on older designs,” says Rob Cinq Mars, President of the engineering consultancy Free Flow Energy . The marine energy industry is generally broken up into a number of different technologies: wave, tidal, current, salinity gradient, ocean thermal and offshore wind. Offshore wind — while still very nascent — is one of the only technologies being deployed on a commercial scale.
12
There's a lot of excitement about wave and tidal technologies today — a result of the broader interest in clean energy. But Cinq Mars is cautious about some of the claims being made by companies. Many tout the benefits of their technologies, but few are actually close to achieving those claims. “Show me the energy,” he says. “Not a lot of these devices are actually generating electricity today.” The small bits of electricity actually being generated usually come in at the US $0.40 per kilowatt-hour (kWh) range.
Technological successes in marine energy over the last 165 years have been incremental. But with the emergence of new materials, sophisticated electronics and unprecedented amounts of money being invested in new ocean energy technologies, the industry is looking far different than it did in the past. In fact, says Richard Meyer, President of the Ocean Energy Council , it has changed more in the last few years than it has over the last century. “Two or three years ago...it was really only small laboratory testing of devices. These days they've got things in the water, they've got sites selected and they're worrying about regulations. Things have really come a long way in a short time,” says Meyer. Today’s marine renewable energy industry is commonly compared to the wind industry of the 1980's and early 1990's. At that time, there were many competing technologies being developed and thousands of turbines were broken during the testing process, says Meyer. Eventually, certain designs won out, parts for those machines were standardized, and a supply chain was created to service them. The marine energy industry will have to go through the same culling process. “We won't break thousands [of turbines] but it may be a lot before we get somewhere. Ocean energy is about 15 years behind wind energy, but it won't tak- 15 years to catch up,” he says. With only 10 megawatts of installed marine energy capacity around the world, the industry has a long way to go before it catches up with the more than 120 gigawatts of global wind capacity. In theory, the oceans could supply us with a lot of energy. The International Energy Agency estimates that tidal, wave, current, salinity gradient and ocean thermal technologies could represent more than 100,000 terawatt-hours of energy each year. There remain a number of difficulties that companies must face in order to bring the industry to this scale. The high cost of demonstrating projects remains a significant problem, especially recently because of the lack of capital available due to the financial crisis. As later stage companies
13
get further along in the testing process, cash-burn rates accelerate and the need for capital increases. But many investors are hesitant to touch risky, unproven technologies.
Firms like Ocean Renewable Power Company (ORPC) know a lot about the financial difficulties of later-stage testing. ORPC has been developing its cross-flow turbine for ocean and river currents since 2004. Last fall, it tested a 30-kilowatt (kW) pilot version in the Bay of Fundy off the coast of Maine. Bad weather, broken measurement instruments and incorrectly sized turbine foils were some of the setbacks the team experienced, says ORPC President Chris Sauer. When the company starts testing its 60-kW pre-commercial unit this fall, those setbacks will be much more expensive. “We are in this for the long haul...we knew that we needed to find a really strong, strategic partner that has some financial strength,” says Sauer. Like many other companies, ORPC was unable to raise any private equity after the financial markets broke down last fall. However, Sauer says that the company has teamed up with a strategic partner that will get it through the next testing phase and allow it to demonstrate the commercial viability of its turbine by the end of the year. ORPC has not yet released any details of the partnership. Some companies haven't been as lucky. Pelamis Wave Power, which developed the first commercial-scale wave project off the coast of Portugal, is now trying to find a new investor. It's primary partner, Babcock and Brown, went bankrupt in March. In the meantime, the Pelamis devices are sitting idle while the company tries to find the money to fix them. Another leading developer, Finavera Renewables , announced in February that it would temporarily abandon the wave energy business in order to focus on wind. That announcement came more than a year after its device sank off the coast of Oregon . Finavera says it will try to bring in new partners for future development of the AquaBuOY technology. As if these short term testing problems weren't difficult enough, understanding the long-term viability of these devices is even more uncertain. None of them have been in the treacherous sea environment for very long. “Everyone agrees that survivability is the key technology challenge,” says John Miller, Director of the New England Marine Renewable Energy Center . “I think in the past, there wasn't a full appreciation for the challenges involved. Now there is.” Once technologies are ready to be deployed on a commercial or pre-commercial scale, a long and complex permitting process must be completed. This process can also be a problem for inexperienced, cash-strapped companies — especially in the U.S. where the layers of local, state and federal regulations can be difficult to navigate.
14
These demanding financial, technological and regulatory requirements will eventually weed out the weak companies and bring the companies with the best technology and project management skills to the top. “You have to be able to do it all. If you want to be successful in this industry, you need to understand the whole package of project development,” says ORPC's Sauer. “This is not just about a technology.” A number of players have entered the market without recognizing the scope of the challenges, he says. “I do think in marine renewables, the euphoria has subsided a bit. People realize now what we realized a long time ago — that this is not an overnight thing. It takes hard work and it takes hard work over a long period of time,” says Sauer.
15
