What is happening?

Yes. Earth is already showing many signs of worldwide climate change.

1. Average temperatures have climbed 1.4 degrees Fahrenheit (0.8 degree Celsius) around the world since 1880, much of this in recent decades, according to NASA’s Goddard Institute for Space Studies.
2. The rate of warming is increasing. The 20th century’s last two decades were the hottest in 400 years and possibly the warmest for several millennia, according to a number of climate studies. And the United Nations’ Intergovernmental Panel on Climate Change (IPCC) reports that 11 of the past 12 years are among the dozen warmest since 1850.
3. The Arctic is feeling the effects the most. Average temperatures in Alaska, western Canada, and eastern Russia have risen at twice the global average, according to the multinational Arctic Climate Impact Assessment report compiled between 2000 and 2004.
4. Arctic ice is rapidly disappearing, and the region may have its first completely ice-free summer by 2040 or earlier. Polar bears and indigenous cultures are already suffering from the sea-ice loss.
5. Glaciers and mountain snows are rapidly melting—for example, Montana’s Glacier National Park now has only 27 glaciers, versus 150 in 1910. In the Northern Hemisphere, thaws also come a week earlier in spring and freezes begin a week later.
6. Coral reefs, which are highly sensitive to small changes in water temperature, suffered the worst bleaching—or die-off in response to stress—ever recorded in 1998, with some areas seeing bleach rates of 70 percent. Experts expect these sorts of events to increase in frequency and intensity in the next 50 years as sea temperatures rise.
7. An upsurge in the amount of extreme weather events, such as wildfires, heat waves, and strong tropical storms, is also attributed in part to climate change by some experts.

The report, based on the work of some 2,500 scientists in more than 130 countries, concluded that humans have caused all or most of the current planetary warming. Human-caused global warming is often called anthropogenic climate change.

1. Industrialization, deforestation, and pollution have greatly increased atmospheric concentrations of water vapor, carbon dioxide, methane, and nitrous oxide, all greenhouse gases that help trap heat near Earth’s surface. (See an interactive feature on how global warming works.)
2. Humans are pouring carbon dioxide into the atmosphere much faster than plants and oceans can absorb it.
3. These gases persist in the atmosphere for years, meaning that even if such emissions were eliminated today, it would not immediately stop global warming.
4. Some experts point out that natural cycles in Earth’s orbit can alter the planet’s exposure to sunlight, which may explain the current trend. Earth has indeed experienced warming and cooling cycles roughly every hundred thousand years due to these orbital shifts, but such changes have occurred over the span of several centuries. Today’s changes have taken place over the past hundred years or less.
5. Other recent research has suggested that the effects of variations in the sun’s output are “negligible” as a factor in warming, but other, more complicated solar mechanisms could possibly play a role.

What’s Going to Happen?

A follow-up report by the IPCC released in April 2007 warned that global warming could lead to large-scale food and water shortages and have catastrophic effects on wildlife.

1. Sea level could rise between 7 and 23 inches (18 to 59 centimeters) by century’s end, the IPCC’s February 2007 report projects. Rises of just 4 inches (10 centimeters) could flood many South Seas islands and swamp large parts of Southeast Asia.
2. Some hundred million people live within 3 feet (1 meter) of mean sea level, and much of the world’s population is concentrated in vulnerable coastal cities. In the U.S., Louisiana and Florida are especially at risk.
3. Glaciers around the world could melt, causing sea levels to rise while creating water shortages in regions dependent on runoff for fresh water.
4. Strong hurricanes, droughts, heat waves, wildfires, and other natural disasters may become commonplace in many parts of the world. The growth of deserts may also cause food shortages in many places.
5. More than a million species face extinction from disappearing habitat, changing ecosystems, and acidifying oceans.
6. The ocean’s circulation system, known as the ocean conveyor belt, could be permanently altered, causing a mini-ice age in Western Europe and other rapid changes.
7. At some point in the future, warming could become uncontrollable by creating a so-called positive feedback effect. Rising temperatures could release additional greenhouse gases by unlocking methane in permafrost and undersea deposits, freeing carbon trapped in sea ice, and causing increased evaporation of water.

How does Solar Energy Work?

The answers are as simple as you warming up in the sun and plants growing in your garden.

And it’s as complex as using solar panels and photovoltaic cells to make electricity. Solar energy power. It’s as complex as the human beings that use it.

Plants convert solar energy into chemical energy through photosynthesis. Eventually they became the fossil fuels that we now use so abundantly. On this page I will focus on human-made solar energy applications in answering part of your question: how does solar energy work?

Even then, answering “how does solar energy work?” completely will somewhat depend on the purpose and type of application used to harness solar energy. Some of those aspects are covered more fully elsewhere (diy solar heating). And of course you must have broader solar energy information too.

For electricity, you would have a solar photovoltaic (PV) panel. These come in various sizes according to your needs.

Although traditionally it is more costly to have solar PV panels than solar water heaters, with new technologies rapidly emerging, the cost is fast becoming affordable for all.

So, you’re ready to go through this with me now? How does solar energy work?

Let’s go.

Solar energy can be direct or indirect, or active or passive. ‘How does solar energy work?’ is a question of which the answers can be classified also by focus type.

First, there are two approaches towards solar energy conversion into energy we may use, both involving the use of a solar panel. Let’s start with those shall we? These are

• Solar Thermal
• Photovoltaic

Solar thermal

The solar thermal method uses energy from the sun directly to generate heat. Solar panels can be used to collect heat from the sun to capture its heat and transfer it for water and space heating in buildings. Commonly such panels are positioned to maximise absorption of heat from the sun throughout the day and contain tubing through which water circulates. This tubing is known as solar thermal collectors There is also an indirect method where not water but a non-toxic anti-freeze liquid is used. The sun warms this liquid which in turn transfers this heat to water held in a tank. Passive thermal building design is as simple as designing to maximise the sun’s use.

Photovoltaic

This method converts the sun’s power into electricity. This is the photovoltaic process.

How does solar energy work? The solar cell: it’s simple and it’s complex!

• Solar cells, or photovoltaic cells are often silicon-based pieces of material that absorb the sun’s light. Not warmth, as in the thermal application
• Many of these solar cells are often combined in solar panels
• Numbers of solar panels can be combined and interlinked for greater power
• Solar energy excites the electrons in the solar cell and electricity is produced
• This electricity is in the form of direct current or DC
• DC however is not useable for most common purposes
• So, next DC power is transformed through an inverter to alternating current, or AC at 120 Volt, a common-use voltage
• A small amount of solar energy is lost in this DC to AC conversion but is now ready for distribution to household appliances night time use and reduced sunlight
• You may be connected to the regular power grid. It may be possible to feed any excess energy that your batteries cannot hold, back to the grid. In this way you may become a green contributor to a public utility.

A further classification that I need to cover in answering your question How does solar energy work? is this one.

Direct and indirect solar energy

Direct solar energy

Using direct solar power involves only one step in transforming it to useable energy, its electromagnetic radiation. Some examples of direct solar energy include

• Sunlight striking a solar cell by which electricity is immediately generated
• Sunlight that is absorbed by the dark surface warms water in solar thermal collectors
• Sunlight absorbed by a fibre optic cable that is fixed on the exterior of a building and lights the inside
• Amazingly a solar sail on a spacecraft can move it through the direct force of sunlight. How does solar energy work? Mysteriously it seems sometimes.

Indirect solar energy

You probably guessed it! This process involves more than one step from sunlight to useable energy. Here are some examples

• Plants convert sunlight into chemical energy, including carbon. Biofuel can be made from them as well as methane gas and hydrogen without waiting billions of years for them to turn into fossil fuels.
• Hydroelectric dams and wind turbines derive energy from solar-caused wind, rain and other climatic interactions
• Ocean thermal energy is indirect too through its solar-caused differences in temperatures at various depths and wave movement by the wind

After all this, I still have not answered your question: “What is solar energy?” as fully as I might. So, keep moving along with me please…

Active and passive solar energy systems

Passive

A passive system only requires direct sunlight without the aid of any other energy. Sunlight warming an area through a window for example is used in housing and hothouses. Passive solar water heaters for instance use no pump to circulate its water.

Active

And yes, active systems do use the aid of energy besides that of the sun to make them work. Active systems may have electronic tracking devices to maximise sunlight absorption. They may use electric pumps, air blowers, shutters and so on. They can be computer-controlled.

Another way of answering “How does solar energy work?” is by focus type of the solar collector.

Focus types

When very high temperatures are required from solar radiation, its normally diffuse, non-concentrated, light is not enough. Solar energy applications can therefore also be classified as

• Point focus
• Line focus
• Non-focus

Point focus

A saucer-shaped, or parabolic, dish is used to focus diffuse sunlight into a concentrated point of solar radiation. At this point a cluster of solar cells, or a thermal energy receiver convert this radiation into electricity.

Line focus

Same principle as point focus except that here a trough shaped parabolic dish or line of mirrors concentrate the sun’s light which is then converted into electricity.

Non-focus

These systems are those we most commonly think of as solar collectors. Solar thermal panels and solar cell panels are among these. It is an advantage that these systems can use diffuse sun light without further adaptation as above. Concentrating sunlight is of course a more indirect use of solar energy. And greater technological complexity often means higher costs.

Well, that’s it. The basics of how solar energy works. Of course this is only one bit of knowledge that you need if you want to choose the best solar hot water heater, solar energy unit, or even a solar backpack!

You also need to know more if you wish to make your own solar energy system.

Wait, there’s more…

Remember, asking how does solar energy work is not enough. Not if you want a truly sustainable world where all people flourish.

A friend of mine, who is a mother of a son with a disability, visited my web site. Not because she wanted to know theanswers to How does solar energy work? She asked me to expand on “the link between disability and environment” and “how we’re all ‘cactus’ if we don’t get our act together and start to take care of one another”. My sentiments exactly. I’ll keep reminding you of that.

There’s an art to living with limits, dependency and fragility. Focus on that, take direct action and don’t be passive. It’s called sustainable living.

Have I answered all your questions about how does solar energy work? Probably not but you will let me know, won’t you?

Solar hot water systems for your home

Solarbase  hot water heating systems use free heat from the sun to warm domestic hot water. A conventional boiler or immersion heater is then used to make the water hotter, or to provide hot water when solar energy is unavailable.

• How do solar water heating systems work?
• The benefits of solar water heating
• Is a solar water heating system suitable for my home?
• Costs, savings and maintenance

How do solar water heating systems work?

Solar water heating systems use solar panels, called collectors, fitted to your roof. These collect heat from the sun and use it to warm water which is stored in a hot water cylinder.

There are two types of solar water heating panels, they are evacuated tubes (like in the picture above) and flat plate collectors. Flat plates collectors can be fixed on the roof tiles or integrated into the roof. However, Solarbase only install evacuated tubes.

An evacuated solar heating panel is more efficient than a conventional flat plate style of panel. It will also out-perform consistently better in cold, cloudy and windy conditions which are unfortunately all too common in the UK.  

An additional benefit of evacuated tube efficiency is the smaller roof panel footprint – something most people find very appealing. Furthermore, having less solar panel area on the roof reduces the fluid content of the heating system enabling a faster response to solar radiation.

Vacuum is by far the best insulation for a solar heating panel. It safeguards the collector from moisture, condensation and pollutants – resulting in increased durability and year-round performance.    

A boiler or immersion heater can be used as a back up to heat the water further to reach the temperature set by the cylinders thermostat when the solar water heating system does not reach that temperature. (The cylinder thermostat should be set at 60 degrees centigrade.)

Larger solar panels can also provide energy to heat your home as well – though usually only in the summer months when home heating is unnecessary.

The benefits of solar water heating

• Hot water throughout the year: the system works all year round, though you’ll need to heat the water further with a boiler or immersion heater during the winter months.
• Cut your bills: sunlight is free, so once you’ve paid for the initial installation your hot water costs will be reduced.
• Cut your carbon footprint: solar hot water is a green, renewable heating system and doesn’t release any harmful carbon dioxide or other pollutants

Solar Photovoltaic Electricity Systems

Solarbase specialises in the design and installation of photovoltaic and solar thermal systems.

This is the time to invest in Solar PV systems, check out the new government legislation on Feed-in Tariff’s due from April 2010.

Solarbase electricity systems capture the sun’s energy using photovoltaic (PV) cells. Solar photovoltaics (PVs) are arrays of cells containing a material that converts solar radiation into direct current electricity which can be used to run household appliances and lighting.

Due to the growing demand for renewable energy sources, the manufacture of solar cells and photovoltaic arrays has advanced dramatically in recent years. Our aim to provide you with all the information you need to make informed decisions for your home. Installing a home solar PV energy system secures your energy supply, lowers your carbon footprint and contributes to a greener future. It is a sound financial investment that delivers savings you can see each month when your electricity bill arrives.

Solarbase offers a variety of solar PV systems that can be configured to meet your home’s needs. We can assist you in choosing and installing the right system for you.

How do photovoltaic (PV) cells work?

PV cells are panels you can attach to your roof or walls. Each cell is made from one or two layers of semiconducting material, usually silicon. When light shines on the cell it creates an electric field across the layers. The stronger the sunshine, the more electricity is produced.
PV cells come in a variety of shapes including "solar tiles" that look like roof tiles to panels and transparent cells that you can use on conservatories and glass.
The strength of a PV cell is measured in kilowatt peak (kWp) – that’s the amount of energy the cell generates in full sunlight.

As Solarbase are government accredited, the Solar Photovoltaic (PV) system is applicable for a government grant of £2,500 towards the cost of the installation.

What are the benefits?

• Environmentally friendly
• Immediately available
• No barriers to installation
• Fit and forget technology
• Minimal maintenance
• Flexible
• Cost effective
• Reduces energy bills

HOW MUCH ENERGY CAN MY SOLAR PV SYSTEM GENERATE?

An average gas heated semi-detached house with four person occupancy will use around 3,300 kWh of electrical energy per year.

In an average year, a south facing 1kWp solar system will generate around 800 kWh.

In order to achieve carbon neutrality in electricity this therefore would require a 4 kWp solar system and a slight change in lifestyle.

For a standard domestic household as described above a 2kWp system is likely to secure at least half the home electricity demand for free for at least twenty years, and perhaps more as appliances become increasingly energy efficient.