I understand value engineering is a systematic approach to provide the necessary functions in a project at the lowest cost without sacrificing functionality. Value engineering can help in attaining sustainability in so many ways. I'll list a few of them.
First of all, projects which require certain expensive materials to carry out can be replaced with alternative ones less cheaper and efficient as well. This helps to save money. For example, instead of depending on electricity from hydroelectric sources of power for lighting systems in buildings and paying bills constantly, solar panels or solar roofing (panels used as roofs for the ceilings of buildings) can be employed in lighting up the system. This provides a constant source of power and cost is also incurred once. I know the UAE is really into value engineering considering the great engineering feats she's been able to carry out in the last 25 years. However the bottom line is that once cost is cut down, there is 'more' money in the system, and more money means a 'little more sustainability'.
Secondly, value engineering puts less pressure on resources. This aids in attaining sustainability. In the UAE for instance, there are various ways of generating electricity for consumption by the population. They include solar, windmills, hydroelectric and even though I'm not so sure, bio-gas too. However in a country like Ghana, the whole of the population depends on hydroelectric power dams. Different sources of electricity have not been created to supplement the existing one. Also, money is spent in a lot of maintenance of the dam because of it being overburdened. Currently, the nation is just recovering from an energy crisis. Ghana depends too much on her water resources for power generation. Value engineering can really solve the problem by decreasing pressure on resources, hence promoting sustainability. UAE is definitely on the right track!
In a country like the UAE, the only limitation i can think of in the implementation of value engineering is less space (land) for projects and the likelihood of the project being supported by the land. However, there have been so many instances where engineers from UAE have overcome that. Take the Burj-al-Arab for instance.