This is a common problem and one that is society-wide, not just restricted to the event industry. Of course a trade off or compromise may be needed to ensure that the event is financially viable (sustainable!) and as long as you can justify your reasoning for not choosing the most sustainable products, and have a plan in place to work towards it, then you are on the pathway. That is more than anyone can ask! For example an event may be placing some of its financial viability on the sale of bottled water but the sustainability objectives will be met if bottled water is not sold! This is a quandary that will have the accountants and sustainability people at odds. The event needs to look at other ways the income could be earned without the sale of waste in waiting. Get creative! It may take some more effort to bring in bulk water dispensers, staff them, and arrange for branded reusable water bottles or water bottle holders, but the figures at the end may pan out….If going ‘organic’ or to 100% biofuel or buying RECs or installing mobile solar, or a full LED lighting rig, or 100 waste staff rather than 50 is more expensive but it can be proven to have significant impacts on the overall sustainability performance, see if you can get a greening sponsor, grant funding, or even research with your customers/audience/delegates if they would be willing to absorb a small increase in ticket price to help the event be more sustainable. Obviously that angle will work with an entertainment event, rather than one that is trying to sell something to the attendees (like and expo)! Paying more for healthy organic and local food is one that you can pass the cost onto event participants if they are buying their food at the event and if you are have the opportunity to pre-promote it, and to shout loudly about it during show days.