Go Solar

June's Sustainable Living Tip

Go solar for abundant clean energy. You can start with simple steps like growing a kitchen garden -- the closer to home your food is grown, the less dirty fossil fuel required. Or you can make the switch to heat and power your home completely by clean solar energy. The sunlight falling on just one acre in Portland could support all the energy needs of one hundred and sixty Maine families.

Facts about Solar Energy

1. By some calculations, the typical meal eaten in Maine requires more than its own weight in fossil fuel for transportation, storage, packaging and synthetic fertilizer. Growing your own food or supporting local organic farmers is a delicious way to "go solar," relying more on the sun than oil for your personal energy.
2. Every year each acre in Portland, Maine, receives over 24,000 gigajoules (GJ) of solar energy. This is 160 times greater than the total annual energy (heating, electricity and transportation) needed by an average family living in Maine.
3. The average Maine family burns 900 gallons of heating oil in a 78% efficient boiler, using about 100 GJ of energy for space heating and hot water annually. That energy can be collected every year by about 21 square meters -- about half the size of a two-car garage -- of solar thermal collectors operating at 80% efficiency.
4. Solar thermal collectors collect the sun's heat. Then fans blow air or pumps circulate liquid to bring this heat inside where it can be used for space heating or hot water.
   
5. The average sized Maine home (200 square meters) built to super-efficient standards would require less than 11 GJ for space heating per year. This would require just 2 square meters -- a little bigger than the hood of a Volvo station wagon -- of solar thermal collectors.
6. The average family in Maine uses about 20 GJ of electricity annually (around 500 kilowatt hours per month). That energy can be collected every year by about 17 square meters -- about 10 feet by 18 feet -- of photovoltaic solar panels operating at 20% efficiency.
7. Photovoltaic (PV) panels directly convert sunlight to electricity. This electricity can then be fed into regular house current, or can be stored in batteries. Maine has a "net metering" law which allows homeowners to "spin their meters backwards" when sending excess electricity to the grid.
   
8. If a family could reduce its monthly electricity consumption to 350 kilowatt hours per month (for example, by replacing an inefficient refrigerator and using clothes drying racks instead of an electric dryer), their annual electricity needs could be met by just 12 square meters of PV panels -- about 10 by 13 feet.
9. The average family in Maine burns 1,300 gallons of gasoline in vehicles that are about 20% efficient at converting fuel to motion, using about 31.5 GJ of energy for personal transportation annually. Most of the energy released by burning gasoline in an internal combustion engine is wasted as heat.
10. It is difficult to use solar energy to produce liquid fuels (such as ethanol) that can replace gasoline. Serious concerns have been raised about the sustainability of growing corn as an ethanol feedstock.
11. If a family could purchase an electric car, which could be easily recharged with electricity generated by solar power, 26 square meters of PV panels -- about 10 feet by 28 feet -- could satisfy their annual transportation needs.
12. Switching from internal combustion engines to electric motors in our cars will allow us to switch from gasoline to solar power for our transportation needs. The batteries in our electric vehicles will allow us to store solar power for use when it is needed. The first all-electric, mass-market cars are expected to be widely available in the United States starting in 2012.
    
13. More solar energy reaches Maine in four hours than our entire state economy uses in a year.
14. Enough solar energy falls on just the 23,450 miles of public road in Maine to power an economy that uses three and a half times as much energy as our state's does. We could stop using all other sources of energy except solar and still have plenty of capacity to grow our economy.
15. More than half of the electricity generated in Maine already comes from renewable energy sources -- primarily hydropower and wood -- that are forms of stored solar power.
16. Per square meter, over one thousand four hundred times more energy is available per year by directly collecting solar energy than by harvesting firewood. In other words, cord wood is approximately 0.07% efficient at storing solar energy. One acre of solar thermal collectors is the energy equivalent of a 1,400 acre wood lot .
    
17. Super insulated water tanks, such as the Marathon hot water heater, can store solar energy for up to two weeks. This allows solar hot water systems to provide hot water at night and during weeks of inclement weather.
    
18. Solar panels capture more energy than is used to manufacture them. Depending on the manufacturing process and how much solar energy is available for the panel to collect, it takes between one and six years for the panel to "pay back" the amount of energy used to create it. Since panels last for up to twenty years, almost every solar panel in use is providing a net energy benefit over its lifetime. Solar panels are now providing the energy to make more solar panels.
19. Wind power derives from solar energy because winds are primarily due to uneven heating of the earth's surface.
20. Although there is much less solar energy available in the winter in Maine than in the summer, the winds in certain locations are stronger in winter. Wind power, hydropower and tidal power can complement solar power by being available at night, in winter, and during overcast periods.
21. In general, solar power is much more reliable than wind power and much easier to install on a wide variety of existing buildings without adverse visual and noise impact. Wind power, on the other hand, lends itself to economies of scale and is generally a cheaper way to generate large amounts of electricity intermittently at specific places, particularly offshore and along ridges.
22. Solar power is easy to incorporate into consumer electronics. Our store sells solar-powered clocks, radios, flashlights and battery chargers. These are fun and easy ways to try out solar power on a small and affordable scale.