Configuration optimization and selection of a photovoltaic-gas integrated energy system considering renewable energy penetration in power grid

Replacing a conventional energy system with an integrated energy system consisting of high-efficiency and renewable energy conversion devices could diminish the consumption of fossil fuels and mitigate environmental issues. A solar photovoltaics-gas integrated energy system using ground source heat pump and electric heater to generate cooling/heating is proposed for a low-cooling and high-heating region. To select the ideal configuration from Pareto solutions with energy, environmental and exergo-environmental optimization, the coefficient of variation and analytic hierarchy processes coupling decision-making method is used considering the variable renewable energy penetration rate in the power grid. The ideal performance between the improved and conventional methods are compared. The results demonstrate that the average energy, carbon and economic saving ratios of the Pareto solutions are 56.8%, 61.9%, and 52.0%. For each 10% increase of renewable energy penetration, the values reduce on average by 2.1%, 2.3%, and 0.5%, because of the lower fuel consumption. The ideal solution has a higher capacity of gas turbine, battery, and heat pump capacity, and the corresponding energy and carbon benefits are higher, but the exergo-environmental cost saving ratio is 8.5% lower with 0.03 $/kWh higher specific cost than in the conventional method.