If Contract Waste falls below the GMT the Authority is obliged to pay the Contractor as if the GMT tonnage had been delivered. In other words the Authority pays for capacity that is not being used to process its waste. This could create a significant reputational issue for the Authority.
If there is other (non Contract) waste that is being landfilled or being sent to another treatment Facility that could more economically be delivered to, and treated at, the facility than it is clearly a more efficient use of that plant and potentially a better environmental outcome if that waste is sent to the facility. The WIDP Contract (Clause 25.3) allows the Authority to procure Top Up Waste to avoid such inefficiency. As the Authority can recover the cost of using the capacity, that would otherwise have been unused, from the party that provided the waste there is an immediate financial benefit to the Authority.
The most likely source of Top Up Waste is likely to be a neighbouring Waste Disposal Authority (WDA) that is still reliant on landfill or has a short term or flexible contract with an EfW operator. The Contract Management Manual should include contact details of the relevant waste officers in nearby WDAs and their Authorities' waste flows and contractual commitments. It should also highlight the need to obtain legal advice before entering arrangements to source Top Up Waste.