Cogeneration

Are you interested in the possibilities of installing a cogeneration plant at your site? Would you like to improve your plant's security of electricity supply? Would you like to take advantage of the increasing price of electricity by selling it from production at near 100% efficiency? Peter Walker Consultants Ltd (PWCL) is one of the few independent engineering consultancies in New Zealand with the experience required to make your project work.

Although the electricity generating companies in New Zealand have the skills to advise you, they are far from independent: they are one of the key players who will share the profits of your project. Although they will pay you for the electricity you generate, there are often a surprising number of associated benefits they receive through your cogeneration plant. PWCL will work on your side to ensure that those benefits are discovered and accounted for, and that the electricity company puts its fair share into what is really a joint venture.

The details of cogeneration often appear daunting to clients, but the basic technology has been successfully applied for decades and should be regarded as mature and proven.

We provide feasibility studies that will consider:

• The cogeneration approach that best suits your plant.
• The capital cost savings that can be obtained through re-use of elements of your plant that are already in place.
• The discovery and accounting of the ancillary benefits for the electricity generator.
• The brokering of a fair three-way contract between the electricity generator, the fuel supplier, and you.

When your cogeneration plant gets the green light we also have the experience required to project manage the entire job. We will specify the plant, organise tenders, and select appropriate contractors. We will define the contractors' scopes of work, write the contracts, schedule an efficient and realistic timetable, and oversee the work. We will be there from the start, right through commissioning, offering you continued support until your operators are confident they can run the plant on their own. We'll be with you every step of the way and never leave you hanging.

Previous Experience

The following is a list of our previous experience that is directly related to cogeneration. All figures are in New Zealand dollars unless otherwise stated.

• Note: PWCL has project managed some $500m of work on the Kiwi Dairies Ltd Whareroa site, taking its milk processing capacity from about 6 million litres per day to in excess of 12 million litres per day. It is one of the largest milk-processing sites in the world.

• Cogeneration Plant - Kiwi/Todd Joint Venture, NZ ($70m)

  Project management for the co-generation plant consisting of four gas turbines (10MW each), four supplementary fired waste heat recovery boilers with a total steam capacity of 180 tph, a 28 MW steam turbine, 11/110 kV transformers and switchyard and 110 kV export line for connection to the national grid.

  The project also included associated buildings, cooling towers and water treatment plant, plus the necessary resource consents etc. Also responsible for designing the steam attemperation system for the supply of conditioned steam to the associated dairy factories, as well as all piping systems, plus managing construction and commissioning of all the plant.

  The primary purpose of the Cogeneration plant is to provide steam and electricity to the dairy factories, with the secondary purpose being to export electricity. This leads to the need for some novel control algorithms to ensure continuous steam and electrical supply while optimising the power generated for export.