introduction

By an offering the reforestation of a large national park in and by Hungary to the Vatican State, the Vatican would be the "first entirely carbon neutral sovereign state". The forest would compensate for the total CO2 emissions of 2007.

It fits in a plan of the Vatican of "going green", and as one news source reports: The Vatican expands its mission from saving souls to saving the planet.

The Vatican does not stand alone in its quest: its supported by the other worldwide institution where people like to gather: The Pub; In the UK there is the initiative for the first Carbon neutral Pub… The Golden Lion in Ashton Hayes.

Its two extremes of a trend gaining ground in a fast way, and more and more serious picked up at urban level. Symbolized also by the initiative of listing a top ten of CO2 neutral city initiatives, by the website "CO2worldcup" . The question is: what are we talking about? Is it a well defined mission, or is it just marketing? In this paper we explore the definitions in use, and the implications if seriously implemented. In other words, an attempt to come to agreed upon definitions and calculations for measuring the 0 or neutral claims.

abstract

What exactly is meant by Carbon neutral city? or 0-energy buildings?

The paper analyses the the claims, targets and system boundaries used in many projects and places, and develops a framework to value the different issues, and relations between systems. Partly based on experiences with the Dutch Carbon neutral cities programme, but largely based on new analyses and thoughts developed in this paper. In the end a overview is presented of how to deal with systems and targets, as a basis for international valorisation of these claims.