Sustainable use and production of energy in the 21st century

Abstract

It is foreseen that oil and gas will continue to be the key energy sources in the 21st century. Therefore, it is important that oil and gas be produced in a sustainable way during the next decades. This requires technology development to ensure that the environmental impact and pollution from these activities are minimal. The following aspects are being highlighted in this paper: • Development of projects with the minimum of impact on the environment and problems for local populations. • Sustainable drilling without the use of oil-based mud, and collection of all drilling waste during offshore drilling operations in the most environmentally sensitive areas. • Treatment of produced water, sand and minerals from the well stream to avoid pollution. • Limitation of flaring to be performed only when required for safety reasons. • Continuous checking of pipelines to ensure that gas pipelines are run within their actual pressure capacity and that oil pipelines are not leaking into rivers and lakes. • Provision of sufficient storage capacity for gas to ensure timely delivery of gas during high demand peaks. • Injection of CO 2 into sealed underground formations where large quantities are produced, such as at LNG factories. • Optimization of production from existing fields to avoid huge amounts of oil and gas being left in place, following a ‘hit and run’ recovery plan. Furthermore, all primary energy sources need to be converted into end-user energy services known as mechanical work, electricity, heating and cooling. In the process of conversion, only a portion of the primary energy is transformed into the new form, while the rest remains unaltered and is lost. The various forms of energy services produced represent different values or qualities, e.g. heat holds an energy quality ranging from 0 and upwards, depending on the temperature difference which is utilized, as defined by the second law of thermodynamics. Energy efficiency in this context may also be defined as the ratio between energy quality output and input. Practically, all fossil fuels are converted into energy services via combustion and heat, i.e. the conversion efficiency is solely determined by temperatures, meaning that high-energy efficiency can only be obtained at large temperature differences, such as in power generation, while ordinary domestic heating will yield a very low efficiency. Given that some 30–40 % of all fossil fuels today are used for domestic heating, representing an end-user energy quality of (say) 1/10 of what is obtained in modern power generation, there is a large potential globally for energy efficiency improvements, not to mention the associated emission reduc tions.