By reducing directly the consumption of electricity from the grid, Solar Panels can save homes 60 to 90 percent of their annual electricity costs. In California, for example, the initial cost of installing a 10kW PV system (about 30 330W modules) is 22,000 (installed), but the federal tax credit is 2,616,280. The average daily power output of the system is 45kWh, the annual power output is 16,425kWh, the annual saving of electricity is 4,599, based on the local price of electricity at 0.28/kWh, and the investment payback period is only 3.5 years. According to the National Renewable Energy Laboratory (NREL), these systems experience a 25-year life expectancy, more than $82,000 gross revenue (net present value), and return on revenue (IRR) of 12.3%.
Government subsidy only boosts the economy. For the year 2023, Germany provides a subsidy of €250 per kilowatt for house Solar Panels (40kW maximum), which is in addition to the self-use savings of €0.34/kWh electricity price, and the annual household electricity bill is reduced by €2,720 on average. After the installation of a 6.6kW system (about AU9,000), Australian households sell electricity at AU0.10/kWh through the feed-intariff, in addition to their own use of electricity, and save AU$1,800 per year, reducing the payback period to 5 years. The domestic photovoltaic projects propagated in China’s rural areas, owing to the help of state subsidy + provincial subsidy, the farmers’ yearly income increased by ¥3,200, and electricity charges returned to zero.
The technology has significantly enhanced the efficiency of power generation. The efficiency of mass-produced TOPCon products was 22.8% in 2023 (PERC products were 21.3%), and the power generation was enhanced by 7% within the same area. Taking a 20㎡ roof as an example, TOPCon component (power 420W) installation is 1.2kWh more than PERC components (400W) each day, and the annual increase is 438kWh, which is $123 worth (United States average price). The laboratory efficiency of perovskite-silicon composite components has surpassed 33.9% (29.4% monocrystalline silicon theoretical limit), and after future commercialization, power generation can be increased by another 15%-20%.
Operating and maintenance cost is as low as 1/8 of traditional energy. Annual maintenance cost of Solar Panels is approximately 150 (cleaning + inverter check), while the maintenance cost of diesel generators is 1,200/ year. According to Arizona home statistics, the 25-year maintenance cost of photovoltaic system amounts to $3,750, which is exactly 6.2% of the 25-year grid cost of electricity. In rural India, PV microgrids boast a kilowatt-hour cost (LCOE) of ₹2.5/kWh, 86% lower than diesel-based power generation (₹18/kWh), with no risk of fuel price volatility.
Climatic conditions affect real returns. Solar Panels installed in Saudi Arabian residences generate 2,200kWh/kW (modules) a year, 120 percent more than Germany (1,000kWh/m²/ year) due to the 2,200kWh/m²/ year of sunshine. Sydney’s 10kW home system generates 14,600kWh a year, meeting 143% of household electricity (surplus electricity sold), while the same-sized system in London generates only 9,500kWh due to rain, meeting 76% of demand.
The actual case verifies the economic benefit. A family in Fukushima, Japan, installed 7kW photovoltaic +10kWh energy storage system, and the electricity bill dropped from the monthly average ¥15,000 to ¥2,300, a reduction of 85%. After the use of photovoltaic + diesel hybrid power supply in Cape Town, South Africa’s villa area, the grid electricity consumption was reduced by 92% and fuel cost consumption was reduced by 67%. According to the International Energy Agency (IEA) data, in 2022 the world’s total installed capacity of residential PV will exceed 580GW, which will reduce homeowners’ electricity bills by more than $22 billion and prevent 430 million tons of carbon emissions.
Industry trends show that the price continues to drop. The price of Solar Panels is down 89% (from 2.5/W to 0.27/W) and installation cost is down 70% since 2010. Bloomberg New Energy Finance predicts that by 2030, the cost of photovoltaic kWh will be 0.01/kWh, 80% lower than coal-fired power plants (0.05/kWh), and the household electricity savings rate is predicted to exceed 95%.