Maintenance Platform Strengthening at Ngawha Geothermal Plant
With the expansion of Top Energy’s geothermal power generation at Ngawha in the Far North, Northlanders now enjoy more reliable access to power than ever before.
But while local consumers enjoy a more stable power supply, staff at the Ngawha power station had concerns about the stability of maintenance platforms at the plant. The platforms suffered from excessive movement, flexing up to 60mm, creating a high sense of unease for those using them. Inadequate access compounded the problem, and Top Energy sought a solution to provide safe access and a higher level of comfort for staff using the platforms.
Collaborating to achieve the optimum outcome
As experienced brownfield engineers, accustomed to working with operational plants, GRIT was approached to provide a solution. Our unified team of engineers, coating specialists and designers all share a passion for complex and challenging projects, and collaborating to achieve the optimum outcome.
This project had its fair share of challenges, with both above- and below-ground services in operation throughout the project. Additionally, the extremely corrosive environment posed its own challenges.
GRIT provided an initial assessment of the platforms, which identified two possible solutions – strengthening or replacement. Close collaboration with our client led to replacement being the desired solution. Strengthening the existing platforms was considered, but would require bracing that would further restrict access, and allow corrosion to continue, as well as being costly.
Customising a solution
The new platform designs engineered by GRIT avoid closed sections, and reduce the amount of bolted sections, to minimise corrosion. Foundations were kept smaller and parts of the existing foundations were utilised in the new designs, to avoid disturbing the earth mat – buried 600mm below ground – which would be a costly exercise.
The existing ladder-style steps would be replaced with stairs making access safer. And fibreglass handrails that had begun to splinter from UV exposure would be replaced with more suitable and corrosion-resistant coated steel handrails.
The result for the client will be a far more fit for purpose solution, providing safety and comfort for its staff, and durability of their asset into the future.