# Status of BIPV and BAPV System for Less Energy-Hungry Building in India--A Review
## 1 Introduction  
India's energy consumption has increased to 931 billion kWh which is double than of the level marked in the year 1990 making it one of the largest energy consumers in the world along with China, the USA and, Russia. In 2014, India's per capita electricity consumption was 900 kWh which was 1/3 of the average worldwide consumption [1; 2]. Also, compared to 1971, Indian per capita energy use has increased from 3116.84 to 7408.31 kWh in 2014. India's energy sources primarily depend on non-renewable coal-based sources which contribute to a massive amount of greenhouse gases [3; 4; 5]. Currently, India is facing urbanization due to the migration of people into larger cities from smaller towns and villages. This transition enhances the necessity of developing new buildings. During 2014-2015, India consumed almost 840 million m\({}^{2}\) floor space for commercial use. Buildings in India, consume 29% of the total energy, of which residential contributes to 20% and commercial to 9% [6]. In residential buildings, lighting and space cooling accounts to one-third of the energy consumption (1-3 kWh/m\({}^{2}\)/month), whereas commercial buildings consume two-third of the total energy (5-25 kWh/m\({}^{2}\)/month) [7]. The phenomenal growth in the building sector will be witnessed by the year 2030 with an annual building rate of 700-900 million sq. m. These buildings consume a considerable amount of energy for heating, ventilation and air conditioning (HVAC) load demand. Further, the indoor air condition rate is growing at a rate of 30% every year. Projected energy usage for 2050, with the current scenario, shows an 85% increment compared to the energy level in 2005 [8]. The present energy consumption scenario, along with future projections, has forced India to take some necessary actions. In 2015, the international energy association (IEA) has set a target to limit the ambient temperature increment to below 2 \({}^{\circ}\)C than the pre-industrial levels. Hence, India should focus on finding out the energy-efficient ways to generate power and also reduce building energy consumption rates. Fortunately, India is blessed with high solar radiation, which receives 6 billion GWh equivalent energy potential per year. The average incident solar radiation in India is 5.1 kWh/m\({}^{2}\)/day (with large regional differences). This makes India deploy solar photovoltaic (PV) technology to meet the IEA target. The PV device is one of the most promising renewable energy technologies, which converts solar energy into environment-friendly electrical energy by using abundant incident solar radiation. Replacing fossil fuel-generated power by secure, clean and suitable PV generated power can mitigate issues like climatic changes [9; 10]. The Ministry of Power, which controls the power sector in India, created an impressive mission through Jawaharlal Nehru National Solar Mission (JNNSM). Previously, JNNSM has set a target to install a PV capacity of 22 GW by the year 2022 which later increased to a more ambitious target of 100 GW [11]. Subsequently, to reduce building energy consumption and generate power from renewable sources in the buildings; zero energy buildings (ZEB) or net-zero energy buildings are also getting a promotion. Hence, addition of the PV system into the building is one of the most holistic approaches, where, PV will generate a benevolent amount of energy, sufficient for the building-energy requirements. The inclusion of PV technologies into buildings include building-integrated photovoltaics (BIPV) and building-applied photovoltaics (BAPV). For the BIPV system, the PV system replaces the traditional building envelopes, such as windows, roofs, walls and itself acts as a building envelope, whereas for the BAPV system, PVs are applied or attached to the building walls or roofs. Both BAPV and BIPV works as an onsite green power generation, reducing the transmission losses, and improving the building's overall performance.