Design and assessment of net zero energy for industrial buildings

Abstract

The level of greenhouse gases (GHG) that are present in our atmosphere are alarming. These gasses, carbon dioxide, CFCs, and others, many of which are released by burning fossil fuels and organic materials, have built up in the earth’s atmosphere. The increasing levels of pollutant gasses in the atmosphere has precipitated the phenomenon known as the greenhouse effect, this in turn has caused Global warming which is affecting the planet’s weather. The disastrous effects of climate change caused by the build-up of “greenhouse” gasses and global warming affects our world in many ways, such an unfavourable weather conditions like floods, drought and rising sea levels. As the global population increases so does the potential of more harmful gas emissions being emitted into the atmosphere. As more factories are built to cater for these growing demands, these factories consume more power and more natural resources to fulfil the populations’ wants and needs. Natural vegetation, which absorbs carbon dioxide and emits oxygen, is being removed to make space for these factories, new houses, and other services. This fact that vegetation can no longer process the quantity of carbon dioxide humans pump into the atmosphere is a key contributor to Global warming. Furthermore, Eskom has one of the worst emissions per kilowatt hour (kWh) in the world due to the coal consumption of its power stations, many facilities emitting large amounts of greenhouse gases and thus resulting in a high carbon footprint. To aid in the reduction of carbon dioxide emissions, facilities can adopt a Carbon Neutral status (where the net harmful emissions are equal to zero). The aim of the present study is to evaluate a cost-effective method that business owners, directors or engineers can follow to assist facilities with their Carbon Neutral journey. The proposed renewable energy solutions for these facilities include the installation of many photovoltaics (PV) to reduce the amount of electrical energy drawn from the National grid and reduce Scope 2 emissions. Moreover, the study will evaluate two facilities, namely Malmesbury Farm and Malmesbury Smallholding as case studies and discuss steps to be taken to minimise their carbon footprint. The initial simulation will be performed using software such as PV Syst and Sunny Design. The data from the simulation and the actual is then compared. Both sites performed better than initially simulated by the PV Syst and Sunny Design simulations. Malmesbury Farm is on track to achieve an actual calculated return on investment of 125 months, this is 40 months less than simulated in Sunny Design and 1 month longer than simulated in PV Syst. The Malmesbury Smallholding has produced considerably more power than expected and is on track to achieve a calculated return on investment of 117 months. This is 52 months less than Sunny Design simulated and 31 months less than PV Syst simulated. Both facilities have considerably reduced their Scope 2 emissions, the Malmesbury Farm has reduced their Scope 2 emissions by 100%, where they have consumed 0 kWh from Eskom over the last year becoming a net zero energy consumer of Eskom power and proud Carbon Neutral Scope 2 emitters. The Malmesbury Smallholding has reduced their Scope 2 emissions by 74.43%, where over the past 12 months their Scope 2 emissions have amounted to only 2.26 tCO₂e compared to 8.83 tCO₂e if no PV system was installed. The case studies prove that the installation of PV can considerably reduce a facilities carbon footprint and have a positive financial return on the investment.