Residential Solar vs Home Wind Power

© Copyright 2008, D. Alan Carter

A small home wind generator or turbine can be a reliable and pollution-free producer of electricity for your home. So too, a small solar electric or photovoltaic (PV) system. So which makes more economical sense to embrace? Let’s compare.

Residential Solar Power - Overview

A solar cell is a semiconductor that absorbs sunlight, releasing electrons in the process. These free electrons then travel into a circuit built into the solar cell to form electrical current. The basic solar cell typically produces only a small amount of power. To produce more, solar cells are interconnected to form panels or modules. Several modules can be installed on a building or at ground-level in a rack to form a PV array. About 10–20 PV arrays can provide enough power for a household. Fewer than that will provide varying degrees of supplemental power in conjunction with other power sources, or to offset utility bills – if grid connected.

A solar cell can produce electricity on cloudy days, but not as much as on sunny days. Electricity can be stored in batteries for use on demand, or – more practically for urban dwellers – fed into and sold to the utility via "net metering" (your electric meter literally spins backward when your excess solar electricity is being retrieved by the utility).

Residential Solar Power - Economics

The economics of residential solar power are driven by variables including the quality of sunlight, system orientation and pitch, electric rates, and the availability of federal, state and local rebates and financial incentives – including tax credits.

A 5 kW residential solar system will typically cost $42,000. That initial price tag can generally be cut in half – or more – through incentives including rebates and tax credits, taking that initial cost down to $20,000. At that price, depending upon your monthly electric bill, expect the payback on the initial investment to run 10-15 years, though that time will accelerate if utility prices increase. With a system life span of 20-30 years, that leaves a considerable span of time in which you’ll be receiving" free" electricity.

Residential Solar Power - Advantages Over Wind

• Extremely low maintenance; no moving parts to wear out.
• Can be less conspicuous than a wind turbine (can be, depending on how conspicuous the roof modules).
• Unlike a wind turbine, solar generates no noise.
• Faster installation with less cabling required.
• The only viable option of the two in areas where wind speeds average less than 9 mph.

Home Wind Power - Overview

A wind generator or wind turbine is a device of rotating blades which converts the kinetic energy in the wind into mechanical energy. Mechanical energy can be tapped directly to power pumps and other machinery, or for most modern purposes including residential applications, the mechanical energy of a wind generator is subsequently converted into electricity.

In a typical urban residential application, a wind generator or wind turbine augments the electrical service provided by the local utility. At wind speeds insufficient to power the generator, the utility provides 100% of the electrical needs to the household. As wind speeds increase, the generator kicks in and provides an increasing share of the electrical burden. Excess electricity, like that generated by residential solar power, is recovered by the utility by way of grid interconnection equipment. At that point, the homeowner is selling electricity to the utility.

In rural residential applications beyond the reach of the power grid, the wind generator supplies 100% of the household’s electrical needs, or is augmented with other power sources (i.e. solar). Off-grid generators will include a bank of batteries to store electricity for use during windless periods.

Home Wind Power - Economics

Expect to pay, as a rule of thumb, $3,000 to $5,000 for every kilowatt of generating capacity. For comparison, that’s about half the cost of a comparable solar system. To make a meaningful contribution to the energy needs of the average household, a generator in the capacity range of 2-10 kW is needed. Doing the math, that pegs the cost of a small wind system at somewhere between $6,000 and $50,000 depending upon capacity. Like residential solar systems, many states (and the federal government) have incentives, tax and rebate programs that can reduce the purchase price for homeowners by up to 50%.

A homeowner spending $50 to $100 per month on electricity should expect to save 10-20% off that utility bill by installing a small, 1 kW wind turbine (a $5,000 initial investment). That same homeowner should realize a 30-60% savings each month with the installation of a 3 kW wind turbine (a $15,000 initial investment). The higher the monthly utility bill, the greater the savings with a small wind system.

The initial investment payback on a home wind generator runs 10-15 years. As with residential solar systems, an investment in a home wind generator will likely increase the value of your home proportionally to the savings on utility bills. And also like residential solar systems, small wind turbines have a life span of 20-30 years. 

Home Wind Power - Advantages Over Solar

• In an optimal location, wind has a lower cost per kWh.
• Slightly lower initial cost.
• More predictable power output in some locations.
• Generates electricity day and night.
• The only viable option of the two in areas of shade or significant overcasting.

The bottom line: it really depends on your geographic location and energy requirements. Based on a cost per produced kWh (kilowatt hour) of electricity, an optimized wind system has a slight advantage over solar. But factor in ambient noise, aesthetics and maintenance, and residential solar power gets the nod. Keep in mind that much depends on wind/solar resources in your area. If you live in a windless hollow, solar is the way to go. If you live in Seattle with 240 overcast days per year, home wind power has the definite advantage.

Then again, there’s always the idea of a hybrid of the two, thereby providing superior performance over a wide range of conditions. For info on do's and don'ts, net metering, costs and incentives relating to home wind power, see our Top 10 Q&A for Home Wind Generators.

– D. Alan Carter