96
Improving Global Quality of Life
Through Optimum Use and Innovation of Welding and Joining Technologies
9.1.8
Power - Renewable
Rising fuel costs, environmental concerns and financial incentives have expanded development and growth
in clean energy alternatives. This includes investment and growth in solar photovoltaics, wind power, fuel
cells, and supporting battery technologies. R&D organisations are assisting global growth in these industries
through design, material selection, welding/joining technologies, numerical modelling, and structural
analysis engineering assistance.
Solar:
The solar photovoltaics industry revenue is expected to rise from $15.6 billion in 2006 to over
$69 billion by 2016. One of the barriers to growth in this sector is the decline in silicon and high cost to process
the material. Advanced manufacturing techniques and alternative materials are now driving down the cost
of silicon. Flexible substrates and other design features are also driving changes in the manufacturing of
solar panels. Thermal conductive adhesives, coatings, and structural joints are among the joining processes
used for solar photovoltaic panels.
Wind:
Although wind power currently only accounts for 1% of energy generation in North America,
significant growth indicates it will continue to expand and mirror European wind initiatives. Similar
to aircraft engines, wind turbines, nacelles, and towers are material and weld intensive and subject to
extreme structural fatigue due to operational conditions.
An increase of the efficiency of the onshore and offshore wind towers is principally possible due to an
increase in the heights (to 100-160 m) with the development of low-cost structures, new solutions for
offshore foundations and improvement of corrosion& fatigue properties of welds. Obviously, newgeneration
large steel towers will require new design, fabrication and welding technologies for steels up to 500 MPa
yield strength. Advanced structural health monitoring (SHM) techniques in combination with engineering
structural integrity assessment rules will be needed for economic and safe operation of these structures in
remote areas.
Batteries:
Growth in the battery market has occurred due to new materials technology and chemical
compounds being introduced. New applications, including the miniaturisation of electronic communication
and entertainment devices, are also placing demands on battery performance which drives technology
improvements. The most rapid growth is in large scale batteries for backup power and transportation.
These cells use pouch style construction which is relatively new to the industry although it is similar to
existing technology used in the food packaging industry. Performance drivers for batteries include shelf life,
durability-cycling, higher output, increased recharge cycles, and lower cost of production. Manufacturing
challenges include material selection, thermal heat management, glass-to-metal seals, polymer joints/seals,
and high production rates.
Fuel Cells:
As energy prices rise and sources of energy become more questionable, greater emphasis is
being placed on improved energy conversion efficiency. This is the case for all forms of energy usage,
including residential, consumer, industrial, transportation, and military areas of application. Government
and industry’s long range energy analysis and planning call for greater emphasis on hydrogen as an efficient
means of converting fuel to electricity for all these application areas. While a great many technical, economic,
and political challenges along the road to a “hydrogen economy” remain, fuel cells are widely considered to
be an essential component in this vision of future energy utilisation. Fuel cells have been used successfully
for decades, one of the most notable examples of which is electric power for space exploration. Hydrogen
and oxygen on board the spacecraft are combined to produce electricity with pure water as the waste
product. While this solution is light-weight, efficient, and clean, it is far from economical in a terrestrial
environment. In fact, current fuel cell systems costs are at least an order of magnitude higher than the cost
targets for commercial viability. Many fuel cell designs call for components that consist of multiple, thin,
stainless steel, sheet assemblies. These thin sheets are required to be joined in a manner that will provide
a leak-tight seal for the life of the product. High-speed (up to 1 meter per second) laser lap seam welding is
emerging as a strong candidate to address this joining challenge.
