Some very interesting things have been happening within the European power industry’s AD700 development programme.

Some very interesting things have been happening within the European power industry’s AD700 development programme, which has been running for ten years and aims to provide the technology for the world’s first 700 °C pulverised coal power plant, with an efficiency in excess of 50%. Remarkably, as an excellent paper by R Blum (presenter), J Bugge and S Kjaer of Dong Energy at the September VGB conference in Stuttgart noted, the project is pretty close to a schedule established a decade a ago and the hope is to have the first demonstration plant in operation by 2014.

E.On has declared itself interested in building a full-scale (550 MWe) demo plant based on AD700 technology – called the 50+ project – at Wilhelmshaven in Germany on this sort of schedule. Significantly, E.On, together with TUV Nord, has been working on the development of capture readiness certification – believed to be the world’s first such standard – for this plant, along with an 1100 MWe coal station the utility hopes to build in Antwerp.

A number of extremely innovative concepts are also being explored within AD700, which can be seen as spin-offs as they promise significant efficiency improvements and cost reductions applicable to present-generation ultra supercritical units as well to the eventual 700 °C plant. One beneficiary could be Dong’s planned Greifswald power station in Germany, where a compact in-line arrangement of boiler and steam turbine – as developed under AD700 – has been adopted.

Phase 1 of AD700 ran from 1998 to 2004 and was carried out under the EU Commission’s Framework Programme (FP) 4, while Phase 2, 2002 to 2006, came under FP 5. Phase 3, 2004 to 2009, component demonstration, should have come under FP6, but that FP, misguidedly, excluded support for fossil fuels. However, AD700 survived this thanks to adoption of a less ambitious project, a component test facility called COMTES 700, at E.On’s Scholven F, as its Phase 3, with finance from the Research Fund for Coal and Steel. Phase 4 is construction of the full-scale demo plant itself and pre-engineering for this plant, the precursor to construction, started in October 2006 and is due for completion by the end of this year.

With carbon concerns now high up the agenda, the AD700 project – with its focus on technology developments that increase efficiencies, which can be funded under FP7 – seems to be gaining momentum – and certainly deserves to be supported.

The Master Cycle, being developed under AD700, is a striking example of what can be achieved and was described in the VGB paper as “a new step along the Carnot track based on a simple modification of the conventional double reheat water/steam cycle.” The basic idea is to shift the IP turbine bleeds from the IP turbines to a separate turbine called the “tuning turbine”, which is fed by steam from the first cold reheat steam line. The tuning turbine has many similarities with a feed pump turbine but steam expansion through it “ends in an IP heater, thus avoiding the complicated condenser and cooling water systems of conventional FPTs” say the Dong authors. The modifications are simple but “they seem to have a deep impact on the water/steam cycle,” they observe, and promise, in combination with other AD700 technologies, efficiencies of up to 53% for coastal sites in northern Europe.

This kind of thing could certainly change the outlook for pulverised coal and could go some way to offsetting the efficiency penalties that future carbon capture technologies will inevitably impose.