Microsoft has built a new office building with a floor area of 27 000 m2 in Unterschleißheim near Munich in Germany. The building features very modern architecture and is supplied with the most modern energy supply and communications technologies. At an early stage of the project the customer decided to use a cogeneration power plant for the energy supply. To be more flexible they also made the decision to go for an energy contracting solution, in which the contractor is responsible for delivery of electrical power, heat and cooling, as well as for back-up and additional power from the grid, supply of natural gas and supply of other sources of energy. Under this regime, the contractor’s services are paid for on the basis of the delivered amount of electricity and heat in kWh.
In 1999 there was a public request for bids for these contracting services. ABB won against several strong competitors, a decisive factor being the progressive and flexible design of contract that ABB was able to offer. Features include 100 per cent financing by an ABB owned bank, standardised design of CHP units, chillers and boilers (using Zantingh technology, which was acquired by ABB) and service on a 24 hour basis, with operation carried out and supervised from a central facility in Essen (from which ABB’s other German CHP plants are also supervised).
In the Microsoft case, the power plant is designed for a yearly supply of:
4 250 000 kWh of electricity;
2 850 000 kWh of heat; and
4 180 000 kWh of cooling for air conditioning.
On basis of these demands ABB installed three reciprocating-engine-based CHP units with an electrical output of 475 kW each and a boiler with a capacity of 2 MW. The cooling demand is supplied by an absorption chiller with a capacity of 800 kW and a compression chiller with a capacity of 500 kW.
The Microsoft data centre needs 400 kW cooling over the entire year. If the ambient temperature is below 5°C free cooling is used for the air conditioning of the data centre – a very environmentally friendly approach. The CHP power plant is also used as an emergency power supply, while about 400 kW is supplied as baseload. Components such as oil supply and cooling towers for the chillers are also part of ABB’s contracting scope. In addition the distribution of the electrical power within the buildings was also financed by ABB. In total ABB’s investment in the Microsoft CHP project has amounted to more than DM 5 million.
The plant is operated according to heat demand. This easily guarantees a yearly energy utilisation of over 70 per cent, which is important for tax advantages in Germany. In fact the estimated yearly utilisation is 88 per cent. ABB buys the back-up and additional power supply from the grid via a regional energy supplier.
The construction time for the plant was about 8 months and it entered operation in September 2000. The CHP plant installation was done in parallel with the completion of the building itself.
Overall, the customer is expected to enjoy savings of over 10 per cent compared with a conventional energy supply solution.
