Can You Run A House Completely On Solar Power?

Solar power is the conversion of the energy from sunlight into electricity. Solar panels composed of photovoltaic cells absorb sunlight and convert it into direct current electricity. This electricity can then be used to power homes and businesses or fed back into the grid. The popularity of home solar systems has risen dramatically in recent years. According to industry research, the amount of solar energy installed has grown at an average annual rate of 24% over the last decade. With solar panel costs decreasing and efficiency increasing, many homeowners are considering going 100% solar powered to take advantage of renewable energy and potentially zero out their electric bills.

This article will examine if it’s feasible and cost-effective to run an entire household on just solar power. We’ll look at how solar panels work, the benefits and challenges of relying solely on the sun for your energy needs, system sizes, battery options, and more. The goal is to provide homeowners with a comprehensive guide to transitioning to a completely solar powered home.

Table of Contents

How Solar Power Works

Solar panels, also known as photovoltaic (PV) panels, convert sunlight directly into electricity through the photovoltaic effect. PV panels are made up of individual solar cells comprised of silicon, a semiconductor material. When sunlight hits the solar cells, the photons from the light energize the electrons in the silicon, knocking them loose from their atoms. The electrons can then flow through the material to produce electricity. The production of an electric current through the absorption of light is known as the photovoltaic effect.

The PV panels have a positive and negative layer that forms an electric field. When the photons hit the PV cells, electrons are knocked loose between the two layers, allowing current to flow. The PV panels have conductive plates on the sides that collect and carry away these electrons in the form of direct current (DC) electricity.

This DC electricity from the solar panels then travels to an inverter, which converts the DC electricity into alternating current (AC) electricity that can be used to power home appliances and equipment. The inverter is connected to the home’s electrical panel and synchronizes the electricity produced by the solar panels with the current from the electric grid. Any excess electricity that isn’t immediately used is fed back into the grid.

References:
https://www.energy.gov/eere/solar/how-does-solar-work
https://www.nationalgrid.com/stories/energy-explained/how-does-solar-power-work

Benefits of Solar Power

Solar power provides several advantages over conventional power sources. First, solar energy is a clean, renewable energy source that does not emit greenhouse gases or other pollutants associated with burning fossil fuels like coal and natural gas (DOE, Enel Green Power). Generating your own electricity from solar panels reduces your carbon footprint and reliance on the electric grid.

Another major benefit is reduced electricity bills. Solar panels can generate electricity to power your home during the day, reducing the amount of electricity you need to buy from the utility (DOE). This provides long-term savings on your energy costs. Any excess solar electricity produced can even be sold back to the grid through net metering programs.

Solar energy also provides energy independence and security. By generating your own renewable electricity, you reduce dependence on your utility company and external fuel sources that are vulnerable to price fluctuations and shortages (DOE). Solar energy is available everywhere the sun shines, giving homeowners control over their energy supply.

Challenges of Going 100% Solar

While solar power provides many benefits, there are some key challenges to running a house completely on solar power. One major challenge is the intermittent nature of solar energy. Solar panels only generate electricity when the sun is shining, so storage is needed for nighttime or cloudy days. Battery storage adds significant costs, with Tesla’s Powerwall system costing around $10,000 for 13.5 kWh of storage capacity (Denholm, 2021). For most homes, multiple days of backup storage would be needed to go completely off-grid, which can cost tens of thousands of dollars.

Connecting the solar system to the electric grid can alleviate the storage requirement, but there are still limitations. During extended cloudy periods, the solar system may not produce enough energy to power the home, requiring the grid as a backup. There are also challenges with selling excess power back to the grid, as net metering policies and rates vary greatly by location (Green Matters, 2023). Upfront system costs, evolving regulations, and infrastructure requirements present additional obstacles to running completely on solar.

While a 100% solar-powered home is technically possible with sufficient solar panels, storage, and the grid as a backup, the costs and complexities make it impractical for most homeowners currently. However, improvements in storage technology and declining solar costs may make it more viable in the future.

Calculating Your Energy Needs

When determining if you can run your house completely on solar power, the first step is auditing your home’s energy use to understand your requirements. This involves taking inventory of all electrical devices and appliances, estimating their wattage and hours of use per day, and calculating the total daily kilowatt-hours (kWh) needed. The US Department of Energy provides a helpful formula for estimating electricity consumption: (Wattage x Hours Used Per Day) / 1000 = Daily kWh use.

When doing an energy audit, pay special attention to major appliances like refrigerators, clothes washers and dryers, dishwashers, and air conditioners as these tend to be the biggest energy users. Focus on purchasing the most energy efficient models when it’s time to replace them, such as ENERGY STAR certified appliances, which can significantly reduce electricity demand. Other ways to lower energy needs are switching to LED lighting, installing low-flow faucets and showerheads, ensuring proper insulation, and utilizing smart power strips.

Once you’ve calculated your total daily electricity requirements, you can properly size a solar system to match your needs and determine if going 100% solar is feasible for your home.

Solar Panel System Size

The size of the solar panel system you need depends on your location and energy usage. The key factors are:

Your average daily kWh usage – How much energy does your household use per day?

Sun hours – The number of peak sun hours in your area. Locations with more sunlight can produce more solar power.
Solar panel wattage – The power output of the individual solar panels you install.

To calculate the system size, take your average kWh per day and divide by the sun hours in your location. This gives you the total watts needed. Then divide the total watts by the wattage of the solar panels you plan to install to get the number of solar panels needed.

For example, if your average energy use is 30 kWh per day, and your location receives 5 peak sun hours per day, you would need a 6,000 W system (30 kWh / 5 sun hours = 6,000 W). If your solar panels are 300W each, you would need 20 panels (6,000 W / 300 W per panel = 20 panels).

Oversizing your system slightly is recommended to account for future energy increases and some loss of efficiency over time. Work with a qualified solar installer to properly size your system.

Battery Storage Options

If you want your home to be powered completely by solar energy, you will need to have battery storage to provide power when the sun is not shining. There are a few main types of batteries that are commonly used for home solar energy storage:

Lithium-ion batteries – These provide a high energy density in a small, lightweight package. Lithium-ion batteries for solar storage have a life expectancy of 5-15 years (CNET). Popular lithium-ion solar batteries include Tesla Powerwall and LG Chem.

Lead-acid batteries – Less expensive but larger and heavier than lithium-ion. Can last 3-5 years with proper maintenance. Often used for off-grid solar systems.

Flow batteries – Store energy in liquid electrolytes. Very long life (20+ years) but currently more expensive. Require more maintenance than lithium-ion.

To power your home overnight and on cloudy days, you will need enough battery capacity to meet your home’s energy needs during those times. The size battery bank you need depends on your energy usage and the number of days you want backup power coverage. Many experts recommend 3-5 days of storage capacity for a completely solar powered home.

Grid-Tied vs Off-Grid

When deciding whether to go completely solar powered, one of the main considerations is whether to connect your solar system to the electrical grid (grid-tied) or be entirely off-grid.

In a grid-tied solar system, the solar panels are connected to the utility grid. Any excess solar energy produced is fed back into the grid, spinning your electricity meter backwards. At night or on cloudy days when solar production is low, you can pull electricity from the grid. Grid-tied systems don’t require battery storage and are generally the most affordable solar option.

With an off-grid solar system, your home is disconnected from the utility grid and relies solely on solar energy stored in batteries. Off-grid homes need a battery bank large enough to provide power 24/7. These systems cost significantly more upfront but provide energy bill independence.

Key differences between grid-tied and off-grid solar:

Grid-tied systems feed excess power to the grid, off-grid systems store energy in batteries.

Grid-tied systems are less expensive upfront since no battery storage is required.
Off-grid systems provide complete energy independence but require batteries and larger solar arrays.
Grid-tied systems rely on net metering policies and are subject to changing utility rates.

Off-grid systems require generators or backup power if batteries are depleted.

When weighing grid-tied vs off-grid, important factors are upfront costs, desire for energy independence, and local net metering rules. For most homes, a grid-tied system is the most practical and affordable solar option.

Costs

The costs of installing a solar panel system can vary greatly depending on system size, type of panels, batteries, and location. According to NerdWallet, the average cost to install solar panels falls between $18,000-$36,000 for an average-sized home system https://www.nerdwallet.com/article/finance/solar-panel-cost. Forbes estimates a range of $5,400 to $18,000 depending on system size and solar potential https://www.forbes.com/home-improvement/solar/cost-of-solar-panels/. Adding battery storage will increase costs by $5,000-$10,000 or more.

There are tax credits and incentives available to help offset the upfront costs. The federal solar tax credit offers a 26% tax credit for systems installed in 2023, and many states and utilities offer additional rebates. The payback period on a solar system in a sunny climate can be 6-8 years when factoring in these incentives. Ongoing maintenance costs are low, mostly limited to inverter replacement every 10-15 years.

Conclusion

Going completely solar for your home’s power needs may seem daunting, but is becoming more feasible due to new innovations like tesla powerwalls for storage and more efficient solar panels. While calculating energy needs, getting proper solar panel sizing and storage right is key, new solutions allow for more flexible capacity.

The upfront cost of solar can be high, but government incentives and long-term savings make it more affordable. Being completely off-grid requires careful planning but provides energy independence. Grid-tied systems are easier and can sell excess power back to the utility.

Overall, with proper planning and increasingly affordable equipment, it’s possible for many homeowners to meet 100% of energy needs with solar. The environmental and independence benefits make it an appealing option for the future as technology continues advancing.