10 interconnected Technology Work Packages (TWPs). TWP Technology package Main technologies Maturity/TRL Main development question 1 Ultra-efficient homes Passive design, insulation, triple glazing, heat recovery ventilation, smart appliances and responsible occupants. High How low can annual and peak demand realistically become? 2 Renewable generation Solar PV, solar façades, residential wind, solar thermal High What generation mix survives a Dutch winter? 3 Electricity sto