Carbon footprint and rebound of large scale building integrated energy production

Building integrated renewable energy production, such as solar energy solutions, reduce the greenhouse gas emissions (GHG) caused by operational energy consumption of buildings. What is less understood, however, is how the investment in these sort of energy solutions affects the overall GHG emissions caused by the person or the company that makes the investment.In general, all economic activities cause environmental impacts. Thus, it has been suggested that the boundaries of environmental assessments should not be based on physical boundaries, but rather monetary budgets. For example, carbon footprints of consumers have revealed that investments in energy efficiency do not only reduce the GHG emissions caused by energy consumption, but also the emissions caused by consumption of other goods and services. This is due to the reality that consumers must withdraw the funds for the investment from some other purposes. However, when the investment in energy efficiency starts to make profit, the situation is reversed. The money saved from declining energy consumption is used on goods and services, which again increases the GHG emissions. The phenomenon is called "the environmental rebound effect". The rebound effect caused by an investment is usually negative, meaning additional GHG reductions. The rebound effect caused by (energy) savings is usually positive, meaning additional GHG emissions prompted by the new consumption enabled by the savings.The purpose of this study is to assess the carbon footprint, and demonstrate the rebound effects over time, caused by investments in large scale building integrated solar energy production. The study takes into account the embodied GHG emissions in the new energy system. The rebound effects are estimated with various assumptions about the alternative consumption or investment. The study highlights why the monetary and time dimensions are important, when considering the overall environmental impacts of green investments.