Lancaster Wind Systems


Products

LWS Energy Solution

What We Do

Products

Wind Turbine

LWS wind turbine is different from other wind turbines.  The LWS wind turbine operates at lower wind speeds and higher wind speeds than other turbines; the increased operating range allows the LWS turbine to generate significantly more power than other turbines.

LWS Energy Solution

The LWS Energy solution allows wind energy can be stored and then released when required this gives the ability to control the wind energy and also supply base load energy to the grid. The LWS system consists of three closed loop systems which are described following.  Each system has a high pressure (HP) and low pressure (LP) side.  Systems one and three are hydraulic and system two is gaseous.  Instead of the generators on the nacelle, (see following picture) two hydraulic pumps are connected to the blades shaft on the nacelle.  As the wind turns, the hydraulic pump increases fluid pressure on the high pressure (HP) line that goes down the tower to the compensator transformers (CT).  Low pressure fluid from the CT is returned to the pump.  This is the first closed system and is the primary energy injection system.

Compensating Transformer (CT)

The CT interconnects the hydraulic and gas systems.  The CT is a proprietary device developed by LWS.  At ground level, the HP line from the nacelle is connected to one side of the CT.  The CT has a hydraulic cylinder in the middle and gas cylinders on each side.  Each cylinder has a piston connected by a common shaft.  As the HP line injects fluid into the ‘primary’ end of the hydraulic cylinder, the driving force of the fluid pushes the piston to the other side of the hydraulic cylinder.  LP fluid is returned to the nacelle. 

Second Closed Loop System

The pistons of the gas cylinder also move in the same direction which then compresses the gas that is supplied from the LP transmission line.  The second closed loop system uses an inert gas nitrogen (N) to charge the transmission storage system.  The compressed gas is stored in the HP transmission line.

Storage

There are two storage transmission lines for the second system, one is the HP transmission line and the other is the LP transmission line.  The compressed gas is forced into the HP transmission line and the compensator transformers will continue compressing gas until the desired maximum operating pressure is achieved.  The amount of storage capacity depends on the length of the transmission lines.  The LP transmission line contains gas from the decompression CT which is the ‘primary’ end of the third closed loop system.  The HP gas transmission line supplies the decompression CT.

Third Closed Loop System

The decompression CT is similar to construction to the compression CT.  The regulated HP gas from the transmission line is injected into one end of the two gas cylinders.  The force created by the gas moves the piston to the other end of the cylinder.  The gas piston movement also moves the hydraulic piston and pressurises the hydraulic fluid which then flows into the hydraulic motors.  This back and forth movement of the pistons provides steady supply of pressurized fluid to the hydraulic motors which are coupled to the generators that produce electricity.

The LP gas coming out of the decompression CT is returned in the LP transmission line and supplies LP gas to the compression CT.  The low pressure hydraulic fluid from the hydraulic motor CT is returned to the decompression CT hydraulic cylinder.  The Lancaster Wind System is a closed loop cycle for both gas and hydraulic fluid.

Illustration of three wind turbines charging the energy storage system with one generatorConceptually, the LWS can accommodate multiple input wind turbines and multiple output generators.  The schematic on the right illustrates three wind turbines charging the energy storage system with one generator.

 

LWS Energy Solution

Other Configurations

Illustration of a single input and output wind turbine and generatorOne of the problems faced by wind turbines is the low revenue generated by them.  Essentially, they are price takers.  That is, they bid into the market at $0.00 and accept the settlement price at the end of the hour.  Depending on the Pool Price settlement mechanism employed, the wind producer reduces the hourly Pool Price.  While this may appear to assist the consumer, it doesn’t since energy producers aware of the price taker effect of wind generators will adjust their bid price accordingly to counteract the price taker effect.  Installation of the LWS as a retrofit, would allow the wind producer to bid firm energy into the market with the knowledge that if the wind should fail during the hour, the storage system can supplement the bid.  Additionally, the energy storage capability would allow the wind producer to offer other services such as spinning reserve or firm peaking power.

Since buried pipe is the storage mechanism for the LWS, installing pipe over a large geographic area will allow the wind producer to capture the wind diversity in the area.  In addition, tapping the pipe will allow serving dispersed local loads.  The storage system that can be accommodated by LWS is only limited by current industry standards of pipe and gas storage.

Benefits

Pool Prices over a one-year period (August 1, 2008 to July 31, 2009) were analysed and during that period, there were 126 instances where Pool Prices were in excess of $500 per MW-Hr.  The average hourly Pool Price was $54.31.  LWS has the ability to enter the Alberta market as a price taker at any time.  This is because the N storage system stores the input energy from the wind turbine power.  Theoretically, LWS can take advantage of high Pool Prices generating additional revenue.

Environmentally Friendly

LWS uses nitrogen (N) as the storage gas.  N is inert, biodegradable and environmentally friendly.  N does not cause corrosion and is an effective inhibitor.  Pipeline engineers long ago solved the problems associated with pipeline failure.  LWS would use the same proven engineering techniques in its design for long distance installation.  And, as noted above in the unlikely case of a pipeline rupture, the escaping gas is effectively benign.  This would allow routing the storage pipe close to energy users with minimum safety hazards.

Carbon Offsets

Alberta Environment (AENV) published Offset Credit Project Guidance Document in February 2008.  Section 2.7.3 establishes an electricity displacement factor of 0.65 tonnes of CO2e/MW-hr of generated electrical energy.  The Pembina Institute published a paper entitled The Climate Implications of Canada’s Oil Sands Development wherein they note on page 8 the cost of CO2e credits at $15/tonne CO2e.  Since LWS is environmentally friendly, i.e. no Green House Gases, they qualify for the full credit of 0.65.