Debate: Does the world need nuclear energy?

This relates to rare earth metals because of the emerging use of Neodymium-Iron-Boron (NdFeB) magnets in the generators of wind turbines. Reliability is particularly important for offshore applications because servicing turbines in the water is problematic and expensive. Traditional Doubly Fed Induction Generators (DFIG) with gearboxes are prone to breakdown. Offshore operating and maintenance costs are variable depending on location but the UK experience with offshore DFIGs has seen O&M take up 23% of total costs. Of these, the gearbox and generator account for 42%. Thus as much as 10% of the capital cost is due to servicing the gearbox and generator.

However Direct Drive Permanent Magnet (DDPM) generators have no moving parts and no gearbox and are therefore much less prone to breakdown. They are quickly becoming the turbine of choice for offshore applications. DDPMs contain NdFeB, and lots of it. Jack Lifton suggests 1 ton NdFeB/MW however I have not seen a source for that. This source suggests 567kg/MW.

http://seekingalpha.com/instablog/345817-eamon-keane/29223-will-offshore-wind-growth-boost-rare-earth-demand

Neodymium global production in 2007 was approximately 11,000 tons. Neodymium use for wind turbines at present is very small but should NdFeB become widespread in offshore wind, this would take up 18% of the 2007 total by 2020 (2000 tons Nd).

There is a lot of research being conducted into making gearboxes more reliable. There is furthermore another generator option – the Direct Drive Synchronous Generator (DDSG) which like the NdFeB magnet variety has no gearbox and is almost as reliable. It has a 30% heavier tower top mass, though. It’s not a given that NdFeB will monopolise offshore generators

Abstract
The objective of this paper is to compare five different generator systems for wind turbines, namely the doubly-fed induction generator with three-stage gearbox (DFIG3G), the direct-drive synchronous generator with electrical excitation (DDSG), the direct-drive permanent-megnet generator (DDPMG), the permanent-magnet generator with single stage gearbox (PMG1G), and the doubly-fed induction generator with single-stage gearbox (DFIG1G). The comparison is based on cost and annual energy yield for a given wind climate. The DFIG3G is a cheap solution using standard components. The DFIG1G seems the most attractive in terms of energy yield divided by cost. The DDPMG has the highest energy yield, but although it is cheaper than the DDSG, it is more expensive than the generator systems with gearbox

http://ieeexplore.ieee.org/Xplore/login.jsp?url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel5%2F60%2F35284%2F01677663.pdf%3Farnumber%3D1677663&authDecision=-203

There is a lot of research being conducted into making gearboxes more reliable. There is furthermore another generator option – the Direct Drive Synchronous Generator (DDSG) which like the NdFeB magnet variety has no gearbox and is almost as reliable. It has a 30% heavier tower top mass, though. It’s not a given that NdFeB will monopolise offshore generators, but it seems likely to take the lion’s share. GE has acquired ScanWind, which uses NdFeB, and other wind companies are also turning to NdFeB.

I can find nothing that indicates that any wind manufacturers are aware of the supply chain issues associated with neodymium. For rare earth mining investors it is safe to assume, however, that in the coming years increased demand for neodymium will come from the wind sector. The extent of this demand remains to be seen.

Two-hundred kg NdFeB per MW translates into approximately 70kg Nd2O3/MW, or 70 tonnes per GW. Up until now, very few turbines have used permanent magnets, with demand of only 3 or 4 tonnes <17>, suggesting present demand of less than 100MW per year. Figure 19 shows the historical and projected wind turbine additions <53, 54>. In 2014, if half the wind turbines were PMG, a requirement of 2.1kt/yr of neodymium oxide would be required (70*30). From Figure 9, this is 10% of current neodymium production capacity.

Wind turbine demand for neodymium is highly unlikely to have a 50% market share by 2014, as it takes time to build factories and road test the technology. 20% may be a realistic figure, which only entails a requirement of about 1kt/yr.

Furthermore, there is always a backstop technology – the traditional DFIG – which can, and I argue will, step in should any shortfall in neodymium appear.
- Eamon Keane