Solar questions & answers

a. CSP - Concentrating Solar Power System questions & answers

Q1. What are solar concentrators?

Solar concentrators use lenses, mirrors, parabolic dishes or other optics to concentrate energy from the sun. Very often, they have a mechanism so that these devices track the path of the sun during the day. In solar thermal applications, troughs or large mirrors amplify sunlight to create heat, which heats a liquid or gas that turns turbines to make electricity.

Q2. What is an EsPOD?

An EsPOD is a class of solar concentrator that collects and focuses the sun’s energy to generate electricity. Through a thermal receiver and a turbine we are able to convert the sun’s energy into electricity.

Q3. Are EsPODs environmentally friendly?

Yes, EsPODs produce zero emissions and use no bio-hazardous fuels to operate. The fuel needed to run an EsPOD is sunlight, which is free. Investing in an EsPOD is like buying a lifetime supply of fuel.

Q4. How much does it cost?

System costs vary according to a variety of factors: system size, components (heating, cooking, distilling, etc), ease of installation, location, government rebates. Our trained representatives can start you on the path to energy independence.

Q5. Do I need batteries for my system?

Batteries are only required if you want back up or produce energy during non day light hours or off peak load times.

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Q6. What's reverse metering?

It is a means of supplying electricity back onto the grid by inter-connection with bi-directional meters. Essentially, it is a way for individuals who produce their own power to put that power back on the grid and get paid or credited for it. Typically, self generation offsets the amount of electricity the customer would have otherwise purchased from the utility company. In cases where the power generation is greater than consumption, this electrical generation is credited to the customer’s monthly electrical bill.

Q7. Do EsPODs work on commercial buildings?

Absolutely! Office buildings, warehouses, schools, hospitals, service stations, government facilities; anywhere there is a demand for electricity, alternative energy can be utilized.

b. Solar Panels questions & answers

Q1. How much space does the system need?

A typical system requires about 7 to 8 square feet for each dollar of your electric bill. This figure varies depending upon your electric rates.

Q2. Do the panels need to be mounted on my roof?

Panels are often mounted on the roof, but can also be mounted on the ground. Ground mounts are great if the house is shaded, or if dormers or other obstructions limit available space on the roof.

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Q3. Do the panels need to face south?

South is best, but panels installed facing east or west still generate a very high percentage of possible power. It is usually more effective (and more attractive) to install the panels in the same plane as the roof direction, rather than build an awkward mount to angle them.

Q4. How long will the system last?

The solar panels have a 25 year power warranty from the manufacturer. This is longer than almost anything else you can buy. The rest of the system has a 5 year warranty in most areas. Inverters can have warranties up to 10 years.

Q5. What happens when the utility has a power outage?

Most systems are “clean power” systems, without batteries. These systems do not generate power when the utility is out, even if it is sunny. If backup power is desired, a battery system can be added. This increases the complexity and cost. Most people find that what they want is clean power, and find that the very occasional outage does not bother them, so they do not purchase the battery option.

Q6. Do I need batteries with the system?

Batteries are only required if you want backup power when the utility is out of service. Without batteries, the system has no way to store power, and for safety reasons cannot produce power without the utility in operation.

Q7. What's reverse metering?

It is a means of supplying electricity back onto the grid by inter-connection with bi-directional meters. Essentially, it is a way for individuals who produce their own power to put that power back on the grid and get paid or credited for it. Typically, self generation offsets the amount of electricity the customer would have otherwise purchased from the utility company. In cases where the power generation is greater than consumption, this electrical generation is credited to the customer’s monthly electrical bill.

Q8. What happens if the panels get covered by snow?

Solar panels need sunshine to generate power. While some sun does make it through several inches of snow, little electricity is generated when the panels are covered with anything. Most power is made during clear sunny days.

Q9. Do I need to install a new roof before the solar panels are installed?

Solar panels will last many years (over 25), and because of this, we want the roof to be in decent condition, as it does not make sense to remove and reinstall the panels after only a few years. However, after the panels are in place, they will greatly reduce the wear on the roof by blocking ultraviolet rays, keeping most snow and ice off the roof, and keeping anything from hitting the roof. Most installations do not require a new roof prior to PV installation.

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Q10. What happens if the panels are shaded?

Solar panels should be installed in areas where they get significant shade-free sun every day. Even small amounts of shade can significantly reduce the output.

Q11. Do I need to clean the panels periodically?

Most of our customers do not clean their panels. In most areas of the country, there is sufficient rain to clean the panels. However, if you are in a dusty area (very near a busy dirt road, very urban area, etc.) you may see a performance gain from cleaning the panels monthly. If necessary, a hose stream is usually sufficient for cleaning. Do not use metal, hard, or abrasive methods for cleaning. Do not spray water on the panels when they are very hot.

Q12. If I sell my property, what effect does Solar panels have on the sale price?

Energy conservation and renewable generation adds value to a home. Surveys have shown that for every $1,000.00 saved per year, $20,000.00 is added to a home's value. Solar energy can be one of the best home improvement investments you make.

Q13. How long does it take to install a PV system?

Typical residential systems take from 2 to 5 days to install. Systems mounted on the ground and systems with batteries are more complex, and may take longer. Most of this time is spent outside your house, so there is little disturbance to you. Commercial systems take several weeks to over a month to install, depending upon size and type of installation.

Q14. Will I have to change any of the wiring in my house?

No. A wind turbine or solar panels are easily retrofitted to virtually any home without the need to change any wiring or appliances. In most cases, the utility will install a bi-directional utility meter to measure how much surplus electricity it is purchasing from the homeowner.

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Q15. Does solar work for commercial buildings?

Solar can be installed on office buildings, warehouses, retail buildings, schools, and government facilities. Anywhere electricity is used, solar electricity can be used.

Wind questions & answers

Q1. Will a small wind turbine save me money?

The wind turbine typically lowers your electricity bill by 50 to 90 percent. It is not uncommon for wind turbine owners with total-electric homes to have monthly utility bills of only $8 to $15 for nine months of the year. In northern parts of the country where less air conditioning is used, the bills can be very low year-round. The amount of money a small wind turbine saves you in the long run will depend upon its cost, the amount of electricity you use, the average wind speed at your site, and other factors.

Q2. What size turbine would I need for my home?

Homes use approximately 10,000 kilowatt-hours (kWh) of electricity per year (about 840 kWh per month). Depending upon the average wind speed in the area, a wind turbine rated in the range of 5 to 15 kilowatts would be required to make a significant contribution to meet this demand.

Q3. How do residential wind turbines work?

A wind turbine, which is installed on top of a tall tower, collects kinetic energy from the wind and converts it to electricity that is compatible with a home's electrical system. In a normal residential application, a home is served simultaneously by the wind turbine and a local utility. If the wind speeds are below cut-in speed (6 - 8 mph) there will be no output from the turbine and all of the needed power is purchased from the utility. As wind speeds increase, turbine output increases and the amount of power purchased from the utility is proportionately decreased. When the turbine produces more power than the house needs, the extra electricity is sold to the utility. All of this is done automatically. There are no batteries in a modern residential wind system. Small wind systems for remote applications operate somewhat differently.

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Q4. How much power can I get from a wind turbine?

The ability to generate electricity is measured in watts. Watts are very small units, so the terms kilowatt (kW, 1,000 watts), megawatt (MW, 1 million watts), and gigawatt (pronounced "jig-a-watt," GW, 1 billion watts) are most commonly used to describe the capacity of generating units like wind turbines or other power plants. Electricity production and consumption are most commonly measured in kilowatt-hours (kWh). A kilowatt-hour means one kilowatt (1,000 watts) of electricity produced or consumed for one hour. One 50-watt light bulb left on for 20 hours consumes one kilowatt-hour of electricity (50 watts x 20 hours = 1,000 watt-hours = 1 kilowatt-hour). The output of a wind turbine depends on the turbine's size and the wind's speed through the rotor.

Example: a 10-kW wind turbine can generate about 10,000 kWh annually at a site with wind speeds averaging 12 miles per hour, or about enough to power a typical household. Wind speed is a crucial element in projecting turbine performance, and a site's wind speed is measured through wind resource assessment prior to a wind system's construction. Generally, annual average wind speeds greater than four meters per second (m/s) (9 mph) are required for small wind electric turbines (less wind is required for water-pumping operations). Utility-scale wind power plants require minimum average wind speeds of 6 m/s (13 mph).

The power available in the wind is proportional to the cube of its speed, which means that doubling the wind speed increases the available power by a factor of eight. The important thing to understand is that what seems like a small difference in wind speed can mean a large difference in available energy and in electricity produced, and therefore, a large difference in the cost of the electricity generated.

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Q5. How much land is needed for a small wind system?

The actual space required for a small wind turbine tower is quite small. It can be as small as one square yard.

Q6. Don't I have to take wind measurements for a year or more?

For most residential systems the cost of taking wind measurements is not justified.

Q7. Are wind turbines noisy?

Wind turbines are not noisy. The evolution of wind farm technology over the past decade has rendered mechanical noise from turbines almost undetectable with the main sound being the aerodynamic swoosh of the blades passing the tower. There are strict guidelines on wind turbines and noise emissions to ensure the protection of residential amenity.

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Q8. Do wind turbines frighten livestock?

Wind farming is popular with farmers, because their land can continue to be used for growing crops or grazing livestock. Sheep, cows and horses are not disturbed by wind turbines.

Q9. How strong does the wind have to blow for the wind turbines to work?

Wind turbines start operating at wind speeds of 4 to 5 metres per second (around 10 miles an hour) and reach maximum power output at around 15 meters/second (around 33 miles per hour). At very high wind speeds, i.e. gale force winds, (25 metres/second, 50+ miles/hour) wind turbines shut down.

Q10. How long do wind turbines last?

A wind turbine typically lasts around 20-25 years. During this time, as with a car, some parts may need replacing.

Q11. Will I have to change any of the wiring in my house?

No. A wind turbine or solar panels are easily retrofitted to virtually any home without the need to change any wiring or appliances. In most cases, the utility will install a bi-directional utility meter to measure how much surplus electricity it is purchasing from the homeowner.

Q12. What is "availability factor"?

Availability factor (or just "availability") is a measurement of the reliability of a wind turbine. Wind turbines have an availability of more than 98% -- higher than most other types of power generate. After two decades of constant engineering refinement, today's wind machines are highly reliable.

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Energy Consumption questions & answers

Q1. What would be a typical energy usage amount?

The average home in the US consumes 10,600 kilowatt hours of energy per year. The three largest areas of energy use in a US home: heating 47%, lighting and appliances 24% and hot water heating 17%.

Q2. What is the consumption of typical household appliances?

Appliance/Equipment Power (watts)

• 4 x 24 watt lamps 96 W
• 42” plasma TV 330 W
• portable phone 6 W
• clock 3 W
• iron 1,100 W
• water pump (automatic) 350 W
• high efficiency refrigerator 150 W

From the data above: If you have the television set on for two hours a day, every day of the year, that’s (365 days x 2 hours) 730 hours. The TV draws 330 watts of power for 730 hours for a total annual energy consumption of (330 watts x 730 hours) 240,900 watt hours. In the standard measurement of kilowatt hours, this is 240.9 kWh.

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Net Metering questions & answers

Q1. What is Net Metering?

Net Metering is the regulatory ability to get credit for electricity you generate with renewable energy and send backwards through your utility meter. Exact provisions vary with each Province, but the effect is to allow you to generate excess power during the day, and use it at night, without needing batteries.