Green Energy

Nearly two centuries ago, the Lehigh Valley’s canals began transporting coal as part of an extensive waterway network that brought fuel from northeast Pennsylvania to the Eastern Seaboard.

Now those canals could be used again to provide energy, this time as a green, renewable source.

A Massachusetts company, New England Hydropower Co., wants to build and manage small hydroelectric plants to harness energy from three legacy dams along the Lehigh Valley’s two major streams.

The state has already pledged taxpayer dollars to one project, at the Chain Dam along the Lehigh River in Easton, and New England Hydropower is looking into two more prospective generator sites in the Lehigh Valley. They are at the Ground Hog Lock, south of Easton along the Delaware Canal in Williams Township, and on the Lehigh Canal in Allentown.

Combined, the projects could provide an average annual generation of 9,500 megawatt-hours, or enough electricity to power 1,300 homes, according to company spokesman Chris Conover, using calculations from the Union of Concerned Scientists.

Privately owned New England Hydropower hopes to complete work on the first hydro plant in 2021, according to Conover. He said the three sites are in the early stages of development, and those plans could change.

The state in March approved a $1.4 million grant for New England Hydropower’s Chain Dam project. The Chain Dam sits along the Lehigh River next to Easton’s picturesque Hugh Moore Park, which includes the National Canal Museum.

Northampton County pledged to match the state funding via a low interest loan, and the company intends to seek private financing for the balance of the estimated $6 million project. The state money required a municipal partner to provide a match, which led the county to pledge up to $1.5 million. County Council voted 7-2 in July 2018 to be a partner.

Officials with knowledge of the Valley proposals are enthused by New England Hydropower’s groundwork and the prospects of harnessing the power of local streams to generate electricity for area homes and offices.

“The thing that appealed to the county was you are taking a canal used for tourism, and applying the old technology in an industrial quarter with modern, renewable energy,” said Steve Barron, Northampton County fiscal affairs director. Barron said he toured New England Hydropower’s first hydroelectric plant, in Meriden, Connecticut.

Conover said the technology used by New England Hydropower can be found in some 300 plants across Europe.

Power from a ‘simple’ technology

New England Hydropower’s proposals for each Lehigh Valley plant feature an Archimedes’ screw turbine. It is a more than 2,000-year-old technology named for the ancient Greek scientist Archimedes, producing power by moving water from the top of a dam or river, which causes the screw to rotate. Energy is extracted by an electrical generator connected to a shaft.

“It is very simple [technology], and it could be a way to care for the canals,” said Allen Sachse, former executive director of the Delaware & Lehigh National Heritage Corridor, which includes Hugh Moore Park and the area at the Ground Hog Lock.

Sachse, who said he is a paid, part-time adviser to New England Hydropower, and other officials say that if the Chain Dam plant were to be built, for example, the company would need to maintain the local canals to ensure water flows.

Northampton County Executive Lamont McClure said in 2018 the company has committed to restoring the Hugh Moore canal system, because installation would require it to be reinforced, refurbished and in some cases redesigned.

He also said, in April, that the county’s loan could be paid back through the sale of power produced by the Chain Dam. In Meriden, according to New England Hydropower, the plant saves the city $20,000 per year in power and property taxes.

Barron, the county’s fiscal affairs director, said the county does not yet have an agreement with New England Hydropower on receiving funds from the Chain Dam project.

“There have been no pledges from NEHC at this time except to build the hydropower plant,” he said.

Conover, who said he did not know the specifics of the loan, said the company would make good if it would have to repay the loan in full, because a hydroelectric system can last years.

“These are not short term,” he said.

But at least one environmental group is concerned about the potential impact of the project.

“It is incredibly disappointing that state and local officials are putting time, energy and taxpayer dollars into projects that have the potential to hurt our rivers and wildlife when there are clean, 100% renewable energy alternatives, like wind and solar, which should be prioritized instead,” said Flora Cardoni of PennEnvironment.

Cardoni said the Delaware is one of the region’s few remaining large rivers free from dams.

“It is crucial to protect the ecological, recreational, and aesthetic beauty of the river so that it can continue to flow freely,” she said.

Conover said the company’s projects, given their scope, would retain the qualities of the area rivers as well as “preserve the historic value of the sites.” He said the work is in line with Pennsylvania Gov. Tom Wolf’s directives on renewable energy.

For the Hugh Moore Park project, he said: “We’re looking forward to working with the consultants to make sure it would not impact the canal boat, or the boat running.”

Meriden officials said New England Hydropower’s plant has not had any negative impacts from the city’s perspective.

New England Hydropower

New England Hydropower, which began in 2012, opened its first and only facility in 2017 at a dam along the Quinnipiac River in Meriden, according to Conover.

But media reports show the 20-ton Archimedes’ screw was left inoperable for about half of 2018 after a malfunction.

“They had an issue with the generator itself,” said Brian Ennis, a Meriden engineer. A fast-turning screw, he said, damaged the generator, but didn’t affect the dam, which is owned by the city.

Conover said a delay in getting repair parts contributed to the lengthy stoppage. “We weathered it,” he said.

Asked what would happen if New England Hydropower’s Lehigh Valley projects did not function as designed, Conover called the question “speculation.”

In submitting its proposals to the Federal Energy Regulatory Commission, New England Hydropower has three years to evaluate the feasibility of the projects, Conover said.

FERC has given preliminary approvals for the two Easton-area projects, spokeswoman Celeste Miller said. The Allentown hydro proposal is pending agency review for a preliminary permit. The proposed plants would also fall under the Pennsylvania Department of Environmental Protection regulatory oversight, according to spokeswoman Colleen Connolly, and they would need various local approvals. For example, Easton owns the Hugh Moore property, so City Council would also have to approve the project.

New England Hydropower’s proposed plants are considered small; the Meriden plant generates 920,000 kilowatt-hours of electricity annually. By comparison, the Hoover Dam on the Nevada-Arizona border generates, on average, about 4 billion kilowatt-hours of power each year — enough to serve 1.3 million people.

Hydroelectric represents 7% of U.S. power production, according to the “2019 Sustainable Energy in America Factbook” by Bloomberg NEF.

Pennsylvania has about 900 megawatts of conventional hydropower, with nearly 1,600 megawatts of storage hydropower capacity, and hundreds of people employed in the hydroelectric field, according to the state DEP.

Conover said it was too soon to say who would buy power generated in the Lehigh Valley, but said it could go on PJM Interconnection, the regional transmission grid that covers Pennsylvania, all or part of 12 other states and the District of Columbia.

Andrew Levitt of PJM said federal law gives small-scale, independent power producers options of selling the power directly to a utility or to a regional transmission operator such as PJM, which is based in Montgomery County.

Lehigh Valley’s hydro history

The Chain Dam and Ground Hog Lock — off Route 611 at the Theodore Roosevelt recreation area along the Delaware Canal in Williams Township — previously served as power sources for industry. Ground Hog Lock had a hydroelectric generating plant that powered a paper company and the Philadelphia and Easton Transit Co. for a trolley line, according to the Delaware & Lehigh National Heritage Corridor. Pennsylvania Power & Light (now PPL) bought the generating plant in 1928 and operated it until it was abandoned in 1954.

“It’s sort of like bringing that history back with the modern, green technology,” Sachse said.

More recently, Allentown has seen hydroelectric plant proposals go through the permitting process without success.

FERC twice issued approvals to the city for hydroelectric projects at a concrete dam on the Lehigh under Hamilton Street, including in the late 1980s and in 2013, according to New England Hydropower. Both times, the city pulled out, the company said in its filing with FERC on the latest Allentown project.

Donald Bernhard, who was Allentown’s community development director during the 1980s, said city officials decided to cancel the earlier proposal over residents’ objections and FERC’s review process, which he said went “like a big pinata, and everybody takes a swing.”

“Even though I thought hydro was good, clean power, you can’t generate power from any source without some impact,” said Bernhard, who is now executive director of the Downtown Allentown Community Development Initiative.

Allentown officials have met with New England Hydropower representatives about the most recent proposal, said Karen El-Chaar, the city’s parks and recreation director.

“We’re open to possibilities and at least dialogue, and to see what comes out of the feasibility studies,” El-Chaar said.

The Delaware River project in Williams Township is on land owned by the state Department of Conservation and Natural Resources, and the Chain Dam canal is also state-controlled, though the city owns Hugh Moore Park.

Conover said company officials have had preliminary talks with department representatives. Spokesman Terry Brady said the agency asked for additional information from New England Hydropower.

“We also stressed strong concerns about the historical significance of that park,” Brady said of Hugh Moore.

Of all the states in the US, Colorado may be the best prepared for a genuine, large-scale energy transition.

For one thing, thanks to its bountiful sunlight and wind, Colorado has enormous potential for renewable energy, most of which is untapped. The state currently generates only 3 percent of its electricity from solar and just under 18 percent from wind.

The political climate is favorable as well. As of earlier this year, Democrats have a “trifecta” in the state, with control over the governorship and both houses of the legislature. Gov. Jared Polis campaigned on a promise to target 100 percent clean electricity by 2040. In their last session, he and the legislature passed a broad suite of bills meant to boost renewable energy, reform utilities, expand EV markets, and decarbonize the state economy.

Colorado has the three main ingredients it needs to get going on clean energy: a healthy economy, plentiful sunlight and wind, and Democrats firmly in charge of state government.

Over the last year or so, energy systems modeler and analyst Christopher Clack, with his team at the energy research outfit Vibrant Clean Energy (VCE), has been taking a close look at what Colorado is capable of in terms of clean energy, and what it might cost.

VCE has built a model called WIS:dom (ahem, “Weather-Informed energy Systems: for design, operations, and markets”). It can simulate the Colorado electricity system with incredibly granular accuracy, down to a 3-kilometer, 5-minute range, year-round. Using that tool, they have simulated various clean-energy initiatives the state might take, and their impact.

I’ve been tracking their progress. In January, I wrote about their initial finding, that Colorado could save $2.5 billion through 2040 by shutting down all its coal plants. In August, I wrote about the second paper, which found that electrifying the state’s transportation fleet is the single biggest decarbonization step it could take and would save consumers money.

Now the third report is out, and it takes on the big question: Can Colorado decarbonize its entire state economy in line with its ambitious goals? (The state’s newly passed climate law sets targets of 50 percent decarbonization by 2030 and 90 percent by 2050.) Can it achieve deep decarbonization and still provide reliable, affordable power?

Spoiler: Yes, it can.

The world may be a raging dumpster fire, but Colorado has the potential to be an island of sanity, moving toward a cleaner, cheaper, healthier energy system in a way that benefits all state residents. Let’s take a look at the paper.

Three scenarios for Colorado, and the cleanest is the cheapest

VCE modeled three scenarios through 2040, using conservative technology cost assumptions and minimizing the import of energy from other states and the need for new transmission infrastructure:

• Business as usual (BAU) keeps all active coal plants running;
• Retire coal pushes all active coal plants into retirement but otherwise lets the electricity sector evolve according to current economics (a mix of wind, solar, and natural gas); and
• Deep decarbonization retires all coal, drives down emissions in the power sector by expanding wind and solar and minimizing natural gas, and electrifies transport (80 percent EVs), space and water heating (60 percent heat pumps), and other sectors. (It also builds 200 MW worth of hydrogen-producing facilities in the state, to help get at the more difficult-to-decarbonize sectors.)

The first and perhaps most important thing to note is that in all scenarios, Coloradans receive a stable, reliable supply of electricity. There is no technical barrier to a mostly decarbonized power sector; the state’s grid is perfectly capable of handling it.

The second thing to note is that in all scenarios, average retail electricity rates decline over time, but they decline most and fastest through deep decarbonization. Cleaner energy benefits all Colorado ratepayers, not just those who have an EV or solar panels.

The most expensive option for Colorado consumers is to keep the coal plants running:

Relative to BAU, deep decarbonization saves Coloradans $4.8 billion in electricity costs through 2040. Of that, $1.5 billion is invested in renewable energy, electrification, and storage technologies, so the savings net out to $3.3 billion.

Third, deep decarbonization brings savings in other sectors as well. VCE reports:

The total savings between 2018 and 2040 for transportation are estimated to be $15.6 billion (real 2017$), which equates to a saving of almost $680 million per year. The total savings between 2018 and 2040 for heating are estimated to be $9.7 billion, which amounts to an annualized saving of $424 million. Therefore, the combined savings are $25.3 billion by 2040, at an annual average amount of approximately $1 billion.

All told, that averages out to annual savings of $97 per electricity customer, $528 per heating customer, and $611 per vehicle through 2040. Not a bad deal for Coloradans.

When all the costs are tallied up — electricity, transportation, and heating system costs — the deep decarbonization scenario comes in the cheapest.

And the cheapest method is also the cleanest

As the name indicates, the deep decarbonization scenario reduces the most greenhouse gas emissions — about twice again what is reduced by the retire-coal scenario.

The key is that retiring coal only reduces emissions in the electricity sector. Electrifying transportation and heating also radically reduce emissions in those sectors.

Overall reductions in greenhouse gas emissions in the deep decarbonization scenario, VCE writes, “are more than 36% by 2025, 56% by 2030 and 69% by 2040 compared with 2005 levels.” Cumulatively through 2040, 1 billion metric tons of carbon dioxide emissions would be avoided. That would put Colorado in line with its legislative goals.

Deep decarbonization cranks up electricity demand and blows out solar and wind

By transitioning transportation, heating, and other sectors over to the power grid, the deep decarbonization scenario increases electricity demand relative to the other scenarios by about 25 percent.

The increase in electricity demand gives grid operators more options. Energy storage, in the form of batteries and EVs, allows much of this demand to be “shifted” to times of day when renewables are more plentiful. A grid with more controllable electricity demand can integrate more renewable energy.

Here’s the kind of power that would be dispatched in the three scenarios:

As you can see, in the retire-coal scenario, the lost coal is replaced with a mix of solar, wind, and natural gas. In the deep decarbonization scenario, coal and natural gas are both replaced (though some residual natural gas remains), occasioning a huge rise in solar, wind, and storage.

Interestingly, though deep decarbonization would mean more electricity demand, it would mean 10 percent lower overall energy demand, mainly because demand would decline in transportation.

Electric vehicles are inherently superior to internal combustion engines in several ways. More of the energy they generate goes to motion, and less to waste heat, so less energy is required to move the same distance (thus the decline in demand). They deliver more torque, for better acceleration. There are fewer moving parts, so they break down less often and are easier to service.

All told, they are cheaper to own and require less energy. Switching to electric vehicles will reduce both total energy costs and per-unit energy costs.

Deep decarbonization means jobs

The “business as usual” model would create almost no additional jobs in the electricity sector. Retire-coal would create some in the early years, as coal plants are shuttered and capacity is built to replace them, but then it would level off.

Deep decarbonization, on the other hand, would create more jobs with each passing year, as enormous amounts of fossil fuel capacity are replaced with enormous amounts of clean energy.

This only stands to reason: if Colorado takes on the much more ambitious task of deep decarbonization, it will take more work to get there.

Cheap renewable energy is changing the whole picture

Obviously, in the real world, Colorado can’t just turn a dial and switch its vehicle fleet to EVs, its residential furnaces to heat pumps, and its natural gas power plants to solar and wind. All of those things will require additional legislation and years of work. There will be political costs, opportunity costs, and transition costs along the way; it won’t be as smooth or efficient in practice as it looks in these graphs.

But if the core story — that Colorado’s cleanest choice is also its cheapest — seems too good to be true, it’s only because most people have failed to fully grasp how cheap clean energy has gotten, and how fast it’s getting cheaper.

Already in Colorado, wind+storage projects are bidding in at prices lower than the operational costs of existing coal plants in the state; solar+storage projects are cheaper than 75 percent of them. It costs less to shut the coal plants down and replace them than to keep them running.

And given the falling costs of energy storage, it’s increasingly possible to envision phasing out natural gas as well, which is why the biggest power utility operating in Colorado, Xcel Energy, recently committed to going 100 percent carbon-free by 2050.

Low-cost renewable energy has endless knock-on effects. Among other things, it means that it’s much, much cheaper to fuel a vehicle with electricity than it is to fuel it with gasoline or diesel. And it’s much cheaper over the long run to heat a building with an electric heat pump than it is to burn natural gas. A large-scale transition to electricity in those and other sectors will save consumers enormous amounts of money.

What Clack’s modeling shows is that it is possible to engineer such a transition while still providing reliable, low-cost electricity to everyone in the state. There is no technical barrier, no need for an entirely new grid, no need to wait on new technologies. The main barriers now, in Colorado as in so many other places across the globe, are social and political. The tools are at hand. All that’s needed are will and courage.

For decades, scientists have sought an affordable and effective way of capturing, storing and releasing solar energy. Researchers in Sweden say they have a solution that would allow the power of the sun’s rays to be used across a range of consumer applications, such as heating homes and vehicles.

Scientists at Chalmers University of Technology in Gothenburg have figured out how to harness the energy and keep it in reserve so it can be released on demand in the form of heat—even decades after it was captured. The innovations include an energy-trapping molecule, a storage system that promises to outperform traditional batteries, at least when it comes to heating, and an energy-storing laminate coating that can be applied to windows and textiles. The breakthroughs, from a team led by researcher Kasper Moth-Poulsen, have garnered praise within the scientific community. Now comes the real test: whether Moth-Poulsen can get investors to back his technology and take it to market.

The system starts with a liquid molecule made up of carbon, hydrogen, and nitrogen. When hit by sunlight, the molecule draws in the sun’s energy and holds it until a catalyst triggers its release as heat. The researchers spent almost a decade and $2.5 million to create a specialized storage unit, which Moth-Poulsen, a 40-year-old professor in the department of chemistry and chemical engineering, says has the stability to outlast the 5-to 10-year life span of typical lithium-ion batteries on the market today.

The most advanced potential commercial use the team developed is a transparent coating that can be applied to home windows, a moving vehicle, or even clothing. The coating collects solar energy and releases heat, reducing electricity required for heating spaces and curbing carbon emissions. Moth-Poulsen is coating an entire building on campus to showcase the technology. The ideal use in the early going, he says, is in relatively small spaces. “This could be heating of electrical vehicles or in houses.”

A big unknown is whether the system can produce electricity. While Moth-Poulsen believes the potential exists, his team is focused for now on heating. His research group is one of about 15 trying to tackle climate change with molecular thermal solar systems. Part of what motivates them is the Paris Agreement, which commits signatories to pursue efforts to limit global warming to 1.5C (2.7F).

Moth-Poulsen plans to spin off a company that would advance the technology and says he’s in talks with venture capital investors. The storage unit could be commercially available in as little as six years and the coating in three, pending the $5 million of additional funding he estimates will be needed to bring the coating to market. In May he won the Arnbergska Prize from the Royal Swedish Academy of Sciences for his solar energy projects.

The professor doesn’t have precise cost estimates for the technology but is aware that it will need to be affordable. One cost advantage is that the system doesn’t need any rare or expensive elements. Jeffrey Grossman, a professor in the department of materials science and engineering at the Massachusetts Institute of Technology who’s also developing energy storage molecules, calls the Chalmers University team’s work “crucial if we want to see this energy conversion storage approach commercialized.”

Peter Schossig, who runs the Fraunhofer Institute for Solar Energy Systems in Freiburg, Germany, says he wants to help turn the Swedish team’s research into a product. But, he says, “There’s still a ways to go.”

Today, the U.S. Department of Energy (DOE) announced selections for $128 million in new projects to advance solar technologies. Through the Office of Energy Efficiency and Renewable Energy’s Solar Energy Technologies Office, DOE will fund 75 innovative research projects that will lower solar electricity costs, while working to boost solar manufacturing, reduce red tape, and make solar systems more resilient to cyberattacks.

“It is undeniable that this Administration has proven its dedication to an ‘all-of-the-above’ energy strategy. In the last three years, we have doubled our solar capacity,” said U.S. Secretary of Energy Rick Perry. “At DOE, we’re working to ensure that solar is more affordable for every American by reducing regulatory burdens and increasing the security and resiliency of our solar energy supply.”

These selections will advance research and development in photovoltaics (PV), concentrating solar-thermal power (CSP), soft costs reduction, innovations in manufacturing, and systems integration. The projects announced today span 22 states. Selections are in the following areas:

• Photovoltaics Research and Development: $23.6 million for 21 projects that aim to reduce the cost of solar photovoltaics by half, helping to provide more affordable electricity for U.S. consumers and businesses. To achieve these deep cost reductions, the PV projects will focus on increasing performance, reducing material and manufacturing costs, and improving the reliability of PV cells, modules, and systems.
• Concentrating Solar Power Research and Development: $30 million for 13 research projects that enable CSP to provide power at any time and in any season, and that work to achieve the 2030 DOE cost target of $0.05 per kilowatt-hour (kWh) for CSP-generated electricity with at least 12 hours of thermal energy storage. This research includes new materials and technologies that significantly reduce the cost of manufacturing, enable new energy storage technologies, and develop solutions that enable a solar field to operate autonomously without any human input.  
• Balance of Systems Soft Cost Reduction: $17.6 million for 19 research projects that work to reduce the costs associated with the non-hardware components of a solar system. These projects help reduce the red tape associated with installing solar and solar-plus-storage systems, since regulatory and financing burdens lead to higher costs for both developers and consumers.
• Innovations in Manufacturing: Hardware Incubator: $6.8 million for 7 research projects from innovative companies with early-stage product ideas that can lower solar costs and rapidly achieve commercialization, with an emphasis on projects that contribute to a strong U.S. solar manufacturing sector.
• Advanced Solar Systems Integration Technologies: $50 million for 15 research projects that improve the ability of grid operators to integrate increasing amounts of solar generation onto the grid in a cost-effective, secure, resilient, and reliable manner. These projects also support development of technology solutions that enhance the visibility and control of PV inverters and sensors, while improving the security of those devices from cyberattack.

Hundreds of John Lewis delivery trucks will begin running on cow power from 2021 as the retailer weans its fleet off polluting diesel fuel and switches to carbon-neutral cow manure.

The retailer will begin using renewable biomethane made from manure slurry for almost 300 John Lewis and Waitrose delivery vans under new plans from its fuel supplier to swap rotting vegetables for poo power at no extra cost.

John Lewis currently runs 80 vans on biomethane from food waste, but plans to expand its green fleet by up to 200 vans within the next 18 months before switching to manure.

The company’s fuel supplier, CNG Fuels, said it also planned to use the manure-based fuel to supply the 200-strong fleet of trucks used by courier service Hermes, as well as the delivery vans of Asda and Argos.

A spokesman for CNG said the majority of the manure used to make the fuel would be sourced from cows, but the slurry might include human sewage too.

According to the heavy vehicle fuelling specialist, using biomethane made from food scraps reduces the carbon emissions of delivery vans by 85% compared with those running on diesel.

But biofuel made from manure is considered carbon-neutral under EU law because it helps stop methane – a greenhouse gas which is 28 times more potent than CO2 – being released into the atmosphere.

The supplier is also looking at ways to update its network of heavy vehicle fuelling stations to include low-carbon hydrogen and powerful battery charging options.

Philip Fjeld, the chief executive of CNG Fuels, said: “Renewable biomethane sourced from manure is currently the best low-carbon solution for HGVs, but we want to be ready to support our customers when other technologies are commercially viable for freight transport.”

Heavy goods vehicles account for 4.2% of UK carbon emissions, so decarbonising the sector is essential to meet the UK’s goal of achieving Net Zero by 2050.

John Lewis announced last year that it planned to switch all its heavy delivery trucks to biomethane-powered versions by 2028. The overhaul will include rolling out over 500 state-of-the-art Waitrose & Partners and John Lewis & Partners delivery trucks powered by renewable biomethane fuel.

Once converted, the new fleet will save more than 49,000 tonnes of carbon emissions every year, or the equivalent carbon footprint of just over 6,000 UK households.

The Sun produces a lot of energy called solar energy. Australia gets 20,000 times more energy from the Sun each day than we do from oil, gas and coal. This solar energy will continue for as long as the Sun lives, which is another 5 billion years.

Solar panels are made of solar cells, which is the part that turns the solar energy in sunlight into electricity.

Solar cells make electricity directly from sunlight. It is the most trusted energy technology ever made, which is why it is used on satellites in space and in remote places on Earth where it is hard to fix problems.

How do solar cells work?

Solar cells are made using silicon atoms. An atom is basically a building block—just like a Lego brick but so tiny you’d need a special machine to see them.

Because the silicon atoms are so small you need trillions and trillions of them for a solar cell.

To make the solar cell you need a wafer layer of silicon, about the same size as a dinner plate but much much thinner—only about three times the thickness of a strand of your hair.

This silicon layer is changed in a special way using hot temperatures of up to 1,000℃. Then, a sheet of metal is put onto the back of the layer and a metal mesh with holes in it, like a net, is put on the front. It is this mesh side of the layer that will face the Sun.

When 60 solar cells are made they are fixed together behind a layer of glass to make a solar panel.

If your house has a solar power system, it will probably have 10 to 50 solar panels attached to your roof. Millions of solar panels are used to make a large solar farm out in the countryside.

Each silicon atom contains extremely tiny and lightweight things called electrons. These electrons each carry a small electric charge.

When sunlight falls on a solar panel it can hit one of the electrons in a silicon atom and knock it free.

These electrons can move around but because of the special way the cell is made they can only go one way, up towards the side that faces the Sun. They can’t go the other way.

So whenever the Sun is shining on the solar cell it causes many electrons to flow upwards but not downwards, and this creates the electric current needed to power things in our homes such as lights, the television and other electrical items.

If the sunlight is bright, then lots of electrons get hit and so lots of electric current can flow. If it is cloudy, then fewer electrons get hit and the current will be cut by three quarters or more.

At night, the solar panel produces no electric power and we need to rely on batteries or other sources of electricity to keep the lights on.

How are solar cells being used?

Solar cells are the cheapest way to make electricity—cheaper than new coal or nuclear power stations. This is why solar cells are being installed around the world about five times faster than coal power stations and 20 times faster than nuclear power stations.

In Australia, nearly all new power stations are either solar power stations or wind farms. Solar and wind electricity can be used to run electric cars in place of polluting petrol cars. Solar and wind electricity can also heat and cool your house and can be used in industry in place of coal and natural gas.

Solar and wind are helping lessen the amount of greenhouse gases which damage our Earth. They are cheap, and they continue to get even cheaper and the more we use it the quicker we can stop using energy that can hurt the Earth (like coal, oil and gas).

What’s more, silicon is the second most common atom in the world (after oxygen). In fact, sand and rocks are made of mostly silicon and oxygen. So, we could never run out of silicon to make more solar cells.