By Teresa Hansen, Associate Editor
Global warming is taken very seriously in the United Kingdom. "Climate change is the most severe problem we are facing today - more serious even than the threat of terrorism." These were the words of Sir David King, the UK Government's Chief Scientific Advisor in March 2004. To combat climate change problems, the United Kingdom adopted an aggressive energy policy that calls for a 60 percent reduction from current carbon dioxide (CO2) emission levels by 2050. The UK government is counting on renewable energy technologies to play a big role in meeting this target.
In a recent presentation about the UK's sustainable energy business, Barry Holmes of the Department of Trade and Investment (DTI), a UK government entity that, among other things, is tasked with promoting a better understanding of the UK renewable energy market and highlighting opportunities for North American companies to develop strategic partnerships with British companies, explained the British Energy Policy. The policy, penned by DTI in February 2003 as a White Paper, Our Energy Future - creating a low carbon economy, calls for 10 percent (about 10 GW) of the UK's electricity to come from renewable sources by 2010. It raises the requirement to 15.4 percent by 2015 and aspires to reach 20 percent by 2020. In 2005, approximately 3.3 percent of the UK's electricity was furnished from renewable resources (including large hydro), making the renewables targets quite aggressive, Holmes said.
Renewables Obligation
As an incentive to UK electricity suppliers to develop renewable generating technologies, the UK government implemented the Renewables Obligation (RO) in April 2002. The RO requires electricity suppliers to purchase a defined proportion of their electricity each year from renewable energy sources. The quota increases each year and the RO remains in force until 2027. Although the RO is technology neutral, it excludes large-scale hydro generation.
If a supplier fails to meet its required obligation of renewable electricity, it is required to pay a penalty for each MWh notproduced by renewable energy. According to Holmes, the current penalty is about £30.50 (~$58) per MWh. The penalties collected from the suppliers not in compliance with the RO are distributed to the electricity suppliers that did meet their RO. Therefore, not only are the noncompliant suppliers required to pay a penalty, they are basically paying a penalty to their competitors. This particular program feature provides electricity suppliers with a lot of incentive to meet their RO.
Electricity suppliers are awarded Renewables Obligation Certificates (ROCs) for each MWh of eligible renewable generation they provide. The ROCs can be sold to suppliers that do not meet their RO obligations; however, ROCs are currently trading at about double their base price of £30.50. In addition, the noncompliant suppliers are once again paying their competitors - more incentive for suppliers to meet their RO.
A capital grants program and R&D spending complement the UK's renewable energy objectives. According to Holmes, various UK government entities will provide £500 million by 2008 to promote renewable technologies. Currently £117 has been promised for offshore wind development, £66 million for biomass and £50 million for marine - wave, tidal current and tidal industry, Holmes said. Other technologies that will receive funding include photovoltaic, landfill gas and community development projects.
Wind Energy
Most experts agree that in the short term at least three-quarters or more of the ROs will be met through wind power, both onshore and offshore. This is because wind power is currently the cheapest scaleable renewable technology available. According to Allison Hill, head of communications for the British Wind Energy Association (BWEA), an existing Scottish wind plant built in 1998 is currently generating electricity at 1.8 pence (~3.3 cents) per kWh. This is less than any natural gas-fired plant in the UK, Hill said. The BWEA expects that 4 GW of onshore and 4 GW of offshore wind generation will be built in the United Kingdom by 2010. The BWEA predicts that the UK's total installed wind capacity will reach 1,500 MW by the end of this year.
The UK's first commercial onshore wind turbines began operating in 1991. Although the installation rate of only 50 MW per year during the first 10 years was somewhat disappointing, the technology is proven and the deployment rate has increased substantially in the past two years.
Offshore wind technology, on the other hand, is much younger and less proven than onshore; however, it holds much promise. The first offshore wind project, which opened in December 2000, consisted of two (2MW each) experimental turbines off the coast of Northumberland, England. Since that time, the UK's offshore wind sector has grown to installation plans for 330 turbines totaling more than 1,100 MW. The first large-scale offshore wind farm to be commissioned, at North Hoyle off the coast of North Wales, has 30 turbines with a combined capacity of 60 MW. Another 60 MW facility at Scroby Sands, off the cost of Great Yarmouth in Norfolk, England, began operation in late March 2005.
Because the UK is a leader in installing large offshore projects and connecting them to the grid, BWEA expects the second phase of offshore development, "round two," to see larger-scale deployments using more powerful machines. The first offshore development phase limited projects to 30 turbines, but round two has no such limit.
Marine Energy
Marine renewable energy is another renewable technology sector that is emerging in the UK. In fact, the world's first commercial grid-connected wave power station is in the UK. Most leading wave energy developers have some involvement there. The UK's long and varied coastline with complex tidal flows makes it an ideal location for marine development. Its diverse coast allows for a broad range of marine-related technologies (see descriptions below) to be developed and tested.
Several UK companies are working on innovative wave technologies. Ocean Power Delivery, Edinburgh, Scotland, has produced a full-scale preproduction wave energy converter (WEC). The 750 kW Pelamis machine is 120 meters long by 3.5 meters wide and weighs 700 tons. It was launched in February 2004 and is now undergoing sea trials.
Wavegen Ltd., Inverness, Scotland, the company that installed the UK's first grid-connected wave power station, has joined forced with Faeroese electricity company SEV to set up a new company called SeWave. The company is researching the feasibility of developing a large-scale, commercially viable wave-powered power station. The project involves Wavegen's oscillating water column (OWC) wave energy conversion technology.
Ocean Power Technologies, a U.S. company, is developing the PowerBuoy, a shallow water device where the movement of a buoy relative to its seabed mooring is used to generate electricity. The company has a full size unit operating off the coast of the Hawaii and is planning to join the UK market.
Armstong Technology Ltd. of North Shields, England, is a partner in the development of the 237-ton prototype Wave Dragon, a slack-moored device consisting of two reflectors that focus waves toward a ramp. The ramp is positioned above a reservoir and the water pours from the ramp through a number of variable speed axial turbines to product power. The prototype has been operating at the Danish Wave Energy Test Station for some time and upon successful completion of the trials, a device five times larger than the test device will be developed for use in the North Sea.
In addition to wave power, UK companies are also leading the way in tidal energy development. Marine Current Turbines Ltd. installed the first offshore tidal turbine, Seaflow, which is undergoing trials off the coast of Devonshire, England. The machine has reached its rated power of 300 kW, has a rotor efficiency in excess of 40 percent and its energy capture has been up to 25 percent, which is better than expected. The company is also developing a large tidal turbine generator. The project, known as SeaGen, will be a grid-connected twin rotor machine.
Engineering Business Ltd. is another UK-based company working on tidal energy projects. The company developed the first full-scale tidal stream generator, Stingray, which was fully funded through the Department of Trade and Industry's New and Renewable Energy Program. Trials for the 150 kW machine were impressive and Engineering Business formed a joint venture with the New and Renewable Energy Co. to create Tidal Energy Business. The new company will further the development of Stingray. The next stage is the design, installation and operation of a 5 MW pre-commercial demonstration wave farm, comprised of 10, 500 kW Stingrays.
There are many elements unrelated to energy capture and conversion that must be addressed when implementing marine energy devices. A wide range of factors such as siting, mooring and other logistical considerations must be incorporated into these projects. The UK's long history with the North Sea development and its growing experience with offshore wind projects, gives it an edge in marine renewables development.
Major Characteristics of Wave and Tidal Technologies
Wave energy is abundant, but unpredictable. The amount of energy that can be created using wave technology varies greatly. Similar to wind turbines, wave devices must be designed to operate at conditions that far exceed average operating conditions.
· Wave devices that ride on the surface of the sea, convert the movement of waves to electricity through movement of different parts of the system. They operate in areas with high wave energy, but must be designed to withstand extreme conditions.
· Subsurface wave devices use pressure changes that are created as waves pass over the structure to generate electricity. This technology has not yet been tested in sea trials.
· Seabed mounted wave devices usually operate in relatively shallow water and use the water's movement as the waves pass to create an oscillating or reciprocating motion in a vane or semi-buoyant structure to create electricity.
Tidal energy is intermittent, but highly predictable. Although not yet quantified, its overall availability is much less than wave energy. Because the speed of tidal flows is relatively consistent, unlike wave energy, it doesn't have to be designed to withstand extreme conditions. In addition, tidal energy devices can provide much more energy per square mile than wave devices or wind projects; the number of suitable sites, however, is limited.
· Tidal turbines work on the same principles as wind turbines. Large underwater rotors, shaped like propellers, are driven by tidal flows, driving generators through large gearboxes.
· Tidal stream generators are usually mounted on the seabed and use the tidal flow to produce mechanical motion that is converted to electricity.
· Tidal barrages are basically dams across bays and estuaries with embedded turbines. The turbines are driven as the tides flow in and out of the enclosed areas.