Renewable and Non-renewable resources

The chapter would begin by defining natural resources as materials or substances occurring in nature that can be used for economic gain. It would then introduce the fundamental classification of these resources into renewable and non-renewable categories, emphasizing the crucial difference in their ability to be replenished over time.

Renewable resources would be explained as those that can be naturally replenished within a human timescale. The chapter would likely provide examples such as:

• Solar energy: Discussing its inexhaustible nature and potential for various uses.
• Wind energy: Explaining its source and how it can be harnessed.
• Water (hydropower): Focusing on the continuous water cycle and its use for generating electricity.
• Forests: Highlighting their ability to regenerate through growth and sustainable management.

The chapter would likely stress the importance of sustainable use and management of renewable resources to ensure their availability for future generations. It might also touch upon the environmental benefits of utilizing renewable energy sources, such as reduced pollution.

Non-renewable resources, on the other hand, would be defined as those that cannot be easily replaced once used because their formation takes geological timescales. Key examples would include:

• Fossil fuels (coal, petroleum, natural gas): Explaining their formation from the remains of ancient organisms and their current significance as energy sources. The chapter would likely discuss their finite nature and the environmental consequences of their combustion (e.g., greenhouse gas emissions).
• Minerals (iron ore, copper, bauxite, etc.): Describing their extraction from the Earth’s crust and their importance in various industries. The chapter might highlight the finite reserves and the environmental impacts of mining.
• Nuclear fuels (uranium): Discussing their use in nuclear power generation and the issues related to nuclear waste.

The chapter would likely emphasize the need for conservation and judicious use of non-renewable resources due to their limited availability. It might also introduce the concept of finding alternative resources and improving recycling efforts.

DISCUSS

Discuss the ways by which you can conserve energy, especially petroleum and electricity, in your homes and school. What changes do you need to make in your daily routine to save these precious resources ?
Ans:

To conserve electricity at home and school, I commit to using LED lighting, prioritizing energy-efficient appliances, disconnecting idle electronics, maximizing daylight and natural airflow, using fans instead of AC when comfortable, optimizing water heater usage, and ensuring lights/fans are off when rooms are empty. My daily habits will shift towards conscious energy consumption and automatic device shutdowns.

For petroleum conservation, I will favor public transport, cycling, or walking over personal vehicles. When driving is necessary, I will carpool and maintain vehicles for optimal fuel efficiency. My daily routine will prioritize eco-friendly travel choices and efficient route planning.

THINK AND ANSWER

Hydroelectricity is considered a good energy option for the future. Why ?
Ans:

Hydroelectricity is a promising energy option for the future for several compelling reasons:

• Sustainable and Everlasting: It harnesses the natural water cycle, a continuously replenished resource driven by solar energy and gravity, ensuring a long-term energy supply unlike finite fossil fuels.
• Clean Power Generation: Unlike fossil fuel plants, it produces no direct greenhouse gas emissions or air pollutants during operation, significantly mitigating climate change and air pollution.
• Dependable Energy Source: While reliant on water flow, which can vary seasonally, it offers a generally reliable and predictable energy source, especially with effective water management and reservoirs.
• Multiple Benefits Beyond Power: Dams and reservoirs often provide flood control, irrigation, water supply, and recreational opportunities in addition to electricity generation.
• Long-Term Cost-Effectiveness: Hydro plants have a long lifespan, and once built, their operating costs are typically lower than those of fuel-dependent power plants.
• Natural Energy Storage: Reservoirs can store potential energy, allowing for on-demand power generation to meet fluctuating electricity needs. Pumped hydro further enhances this storage capability.
• Technological Progress: Ongoing innovations are improving efficiency and reducing the environmental footprint of hydroelectric projects, including run-of-river systems.

VALUE AND LIFE SKILL

Electricity is very important for all of us. We need it for our homes, offices, industries and agriculture.
Make a list of five different ways in which you can save electricity, for instance, switching off fans, ACs, light at home and in school when these thing are not required.
Ans:

A primary way to cut electricity use is by opting for energy-smart lights and devices. Switching to LED bulbs, which consume significantly less power and last longer, is a key step. When buying new appliances like refrigerators or air conditioners, choosing models with high efficiency ratings (like the BEE star labels in India) ensures they operate using less electricity for the same performance.

Another crucial step involves controlling the electricity used by devices when they are turned off. Many electronics still draw a small amount of power even when not actively running. Getting into the habit of unplugging phone chargers, televisions, and gaming systems when they aren’t being used prevents this unnecessary drain.

At home, using fans whenever comfortable is much more energy-efficient than air conditioning. If air conditioning is required, setting the thermostat to a slightly warmer but still comfortable level (around 24-25°C) and ensuring windows and doors are properly sealed minimizes energy loss. Similarly, using water heaters only when necessary and for shorter durations reduces electricity consumption.

Fourthly, maximizing the use of natural light and air can decrease our need for artificial power. Opening curtains and blinds during daylight hours illuminates spaces without requiring electric lights. Allowing natural airflow by opening windows can often provide sufficient cooling, reducing the reliance on fans or air conditioning, particularly in milder weather.

Finally, fostering responsible energy consumption habits and raising awareness among those around us is vital. This includes making a conscious effort to switch off lights, fans, and other electrical equipment immediately after they are no longer needed in any room, whether at home or in school. Encouraging family members, friends, and classmates to adopt these straightforward yet effective practices through discussion and by setting a good example can lead to a widespread impact, establishing a culture of energy conservation within our communities in Pune and beyond.

EXERCISES

A. Fill in the blanks.

1. ______, ______ , ______ are examples of renewable energy resources.

Ans: Sun, water, wind

2. Solar cells use the power supplied by the ________.

Ans: Sunlight

3. Geothermal energy is the heat of the ______.

Ans: Earth

4. Coal, petroleum and natural gas are fossil fuels.

Ans: Fossil
5. __________ is the coal with the highest percentage of coal.

Ans: Anthracite

B. Match the following.

Ans:

C. Choose the correct answer.

1. Photovoltaic cells use the energy of

1. sun
2. wind
3. water
4. tides

Ans : Sun

2. Hydroelectricity is obtained by using

1. wind
2. water
3. coal
4. natural gas

Ans : Water

3. Wind mills have been used for many centuries in

1. the USA
2. the Netherlands
3. Russia
4. India

Ans : The Netherlands

4. The coal that has the highest percentage of carbon is

1. anthracite
2. bituminous
3. lignite
4. peat

Ans : Anthracite

5. The Bhakra-Nangal Dam is situated on the river

1. Yamuna
2. Beas
3. Ravi
4. Satluj

Ans : Satluj

D. State whether the following is True or False.

1. Coal and petroleum are renewable energy resources.
Ans: False.
Correct : Coal and petroleum are non-renewable energy resources.

2. Renewable energy resources have limited supply in nature.
Ans: False.
Correct : Renewable energy resources have unlimited supply in nature.

3. China, USAand Spain are major producers of wind energy.
Ans: True.

4. Coal takes millions of years to form.
Ans: True.

5. The Sardar Sarovar Dam is built on the river Narmada.
Ans: True.

E. Answer the following questions brief.

Question 1.
What are renewable energy resources?
Ans:

Renewable energy resources are naturally replenished energy sources that are sustainable and don’t get used up. They harness natural processes like sunlight (solar), wind, flowing water (hydropower), the Earth’s heat (geothermal), organic matter (biomass), and ocean movements. They are cleaner than fossil fuels and increasingly cost-effective. In Pune, Maharashtra, there’s a growing focus on these resources like solar and wind.

Question 2.

What is the main difference between renewable an non-renewable energy resources?

Ans:

Renewable resources replenish naturally within human timescales, making them sustainable (e.g., solar, wind). Non-renewable resources are finite and take geological timescales to form, meaning they will eventually be depleted (e.g., fossil fuels).

Question 3.

What is tidal energy ?

Ans:

Tidal energy harnesses the predictable rise and fall of sea levels caused by the Moon and Sun’s gravity. Technologies like barrages (dam-like structures), tidal stream generators (underwater turbines), and tidal lagoons capture this energy to produce electricity. It’s a reliable and renewable source with high energy density, but faces challenges like high initial costs, potential environmental impacts, and limited suitable locations. While currently a small part of global energy, ongoing development aims to improve its efficiency and sustainability.

Question 4.

Which countries are major producers of wind power in the world?

Ans:

The top countries generating electricity from wind are China, the USA, Germany, India (including Maharashtra where you are), and Spain. Other notable nations include the UK, France, Brazil, Canada, and Sweden. These countries have made substantial investments in wind farms to produce electricity, driven by aims for cleaner energy and energy independence. China currently leads in both the amount of wind power they can produce and how much they actually generate.

Question 5.

What is biogas ? How is it useful to us ?

Ans:

Biogas is a green fuel made when organic stuff like farm leftovers and kitchen waste breaks down without air. Its main part is methane, similar to what’s in natural gas. We can burn biogas to make electricity, heat our homes and cook, and even use it in cars. This process is a good way to deal with waste, it cuts down on harmful gases going into the air (especially methane), and it leaves behind a natural fertilizer. Biogas setups can also make things more sanitary and give communities their own power source, which is really helpful in the countryside.

Question 6.

What are fossil fuels?

Ans:

Coal, petroleum, and natural gas are examples of energy sources known as fossil fuels, which are not renewable.  These substances originated from the preserved remains of prehistoric vegetation and animals, transformed over millions of years under immense pressure and heat within the Earth’s crust.  While burning these fuels releases the energy they contain, it also emits gases that are a primary cause of climate change. Because their natural formation takes eons, these fuels are considered finite resources, and our rate of consumption far exceeds their natural rate of creation. 

Question 7.

Name a few major producers of petroleum in the world.

Ans:

Based on the most recent data available up to early May 2025, the major petroleum producing countries in the world include:

• United States: Continues to be a leading global producer.
• Saudi Arabia: Holds significant reserves and remains a key exporter.
• Russia: A major producer, although its global role can be influenced by international events.
• Canada: Possesses substantial oil resources, including oil sands.
• China: A significant producer for its large domestic consumption needs.

F. Answer the following questions in one or two paragraph.

Question 1.
Give an account of the use of solar energy.
Ans:

Producing Electricity:

• Photovoltaic (PV) Systems: Solar panels transform sunlight directly into electricity, utilized in setups ranging from residential rooftops to large power plants. Surplus energy can be stored in batteries or fed back into the power grid.
• Concentrated Solar Power (CSP): Mirrors focus sunlight to generate high temperatures, which then create steam to drive turbines, similar to conventional power stations. CSP is often used for large-scale electricity generation and can incorporate thermal storage for power production even when direct sunlight is unavailable.

Heating and Cooling Applications:

• Solar Space Heating: Building designs can be optimized to capture and distribute solar heat during colder months (passive solar design), or dedicated collectors can heat air or fluids for building heating (active solar heating).
• Solar Cooling: Solar energy can power cooling systems through methods like absorption chillers or by supplying electricity for standard air conditioning units.

Diverse Applications:

• Solar Lighting: Powers outdoor lights, streetlights, and indoor lighting systems, particularly in areas not connected to the main power grid.
• Solar Cooking: Specialized ovens and cookers use concentrated sunlight to heat and cook food.
• Solar Water Pumping: Photovoltaic panels can power pumps for irrigation and supplying water to households, especially in remote locations.
• Solar Water Purification: Distillation powered by solar energy can purify water, which is particularly beneficial in arid and coastal regions.
• Industrial Process Heat: Solar thermal systems can provide heat for various industrial applications, including food processing and chemical production.
• Solar Transportation: Research and development are exploring the use of solar energy to power vehicles, boats, and even aircraft.
• Solar Battery Charging: Small solar panels are used to recharge batteries for a wide range of portable devices.

Question 2.

How is hydroelectricity generated?

Ans:

Hydroelectricity is generated by converting the energy of moving water into electricity.  This water is then directed through large pipes towards turbines. The force of the falling water spins these turbines.

The spinning turbines are connected to generators. As the turbines turn, they cause the generators to produce electricity. This electricity is then made suitable for transmission over long distances using devices called transformers.

Essentially, hydroelectric power plants use the energy of water’s movement to turn turbines, which in turn power generators to create electricity, relying on the natural water cycle for a renewable energy source. This method is used in various hydroelectric facilities, including those found in Maharashtra.

Question 3.

Explain briefly geothermal energy.

Ans:

Geothermal energy is power derived from the Earth’s internal heat. This heat, a result of the planet’s formation and the decay of radioactive elements within, manifests as heated water and steam trapped underground.

To utilize this resource, wells are drilled into these subterranean reservoirs. The extracted hot water and steam can then be employed for various purposes:

• Electricity Generation: The pressurized steam drives turbines connected to electrical generators.
• Direct Heating: The hot water can directly warm buildings, greenhouses, and supply heat for industrial applications.
• Geothermal Heat Pumps: These systems leverage the consistent underground temperatures for efficient heating and cooling of structures.

As the Earth continuously generates internal heat and modern power plants have low greenhouse gas emissions, geothermal energy is considered a sustainable and environmentally friendlier energy option. However, its deployment is geographically constrained by the availability of geothermal resources, and initial drilling expenses can be substantial.

Question 4.

What do you know about wind energy?

Ans:

Wind power converts moving air into electricity using turbines. It’s a renewable and clean energy source. Large wind farms and smaller, local installations are used. Advantages include free “fuel” after setup and job creation, but wind availability varies, and there can be noise and visual concerns. India, including Maharashtra, is a significant producer of wind energy, making it a crucial part of the shift to cleaner energy.

Question 5.

Describe the four major types of coal.

Ans:

Coal’s four main types, ranked by carbon and heat:

1. Lignite: Low-rank, brown, low energy, high moisture, used near mines for power.
2. Subbituminous: Black, more energy than lignite, less moisture, easier to transport, mainly for electricity, low sulfur.
3. Bituminous: Mid-rank, more energy than subbituminous, widely used for electricity, some for steel (coke), common in US, black, can be shiny, higher sulfur.
4. Anthracite: High-rank, hard, shiny black, most energy, least moisture, clean burn, used in metals and some heating, least common US mined.

Question 6.

Write a short note on nuclear power.

Ans:

Nuclear power is a method of generating electricity using the heat produced by controlled nuclear fission, typically of uranium. In a nuclear power plant, this heat boils water to create steam, which then drives turbines connected to generators, producing electricity.

Key characteristics of nuclear power include:

• High Energy Density: A small amount of nuclear fuel can produce a large amount of energy.
• Low Greenhouse Gas Emissions: During electricity generation, nuclear power plants release very little carbon dioxide, contributing less to climate change compared to fossil fuels. However, indirect emissions occur during mining, processing, and plant construction.
• Reliable Baseload Power: Nuclear power plants can operate continuously for long periods, providing a stable and reliable source of electricity, unlike some renewable sources that depend on weather conditions.
• Small Land Footprint: Compared to other energy sources like coal or some renewables, nuclear power plants require a relatively small area of land for operation.

However, nuclear power also has significant drawbacks:

• Nuclear Waste: The process produces radioactive waste that remains hazardous for thousands of years, requiring safe and long-term storage solutions, which are complex and costly.
• Risk of Accidents: Although infrequent, accidents at nuclear power plants, such as Chernobyl and Fukushima, can have catastrophic environmental and health consequences.
• High Initial Costs: Building nuclear power plants involves substantial upfront capital investment and long construction times.
• Public Perception: Negative public perception due to safety concerns and waste issues can hinder the growth of nuclear power.

Question 7.

Write about hydroelectric projects in India.

Ans:

Key Aspects:

• Significant Capacity: As of early May 2025, India’s utility-scale hydroelectric capacity is around 46-47 GW, a major contributor to overall power generation. Including smaller projects, the total is even higher.
• Untapped Potential: India’s estimated hydroelectric potential is around 148,700 MW, indicating considerable room for further development.
• Categorization: Projects are mainly classified as large hydro (over 25 MW) and small hydro (25 MW or less), with further sub-categories for smaller projects.
• Geographic Concentration: The Himalayan states hold the largest potential, but significant projects also exist in Maharashtra, Chhattisgarh, Karnataka, and Kerala.
• Major Projects: Key examples include the Tehri Dam (Uttarakhand), Koyna Hydroelectric Project (Maharashtra), Srisailam Dam (Andhra Pradesh & Telangana), Nathpa Jhakri Hydroelectric Station (Himachal Pradesh), and Sardar Sarovar Dam (Gujarat).
• Benefits: These projects offer a clean, renewable energy source, enhance grid stability (especially pumped storage), support water supply for irrigation and drinking, and can aid in flood control.
• Challenges: Development faces hurdles such as environmental concerns (deforestation, biodiversity impact), displacement of communities, geological risks in the Himalayas, water disputes between states, and high initial costs.
• Government Support: The Indian government promotes hydroelectric power through policies recognizing large hydro as renewable, offering tariff benefits, and supporting infrastructure development.
• Focus on Pumped Storage: India is also emphasizing pumped storage projects to store energy and balance the grid, complementing solar and wind power.

Question 8.

Why do we need to conserve our energy resources ?

Ans:

Conserving energy is crucial for several key reasons:

1. Protecting Limited Resources: We heavily rely on non-renewable sources like oil, gas, and coal, which took millions of years to form. We’re using them much faster than they can be replaced, meaning they will eventually run out. Conserving helps these resources last longer for future generations and critical uses.
   
2. Safeguarding the Environment: Burning fossil fuels releases harmful greenhouse gases that cause climate change, leading to rising sea levels and extreme weather. Energy conservation reduces our need for these fuels, lessening pollution and protecting natural environments.
   
3. Saving Money: Using less energy means lower utility bills for everyone – individuals, businesses, and governments. It also reduces the need to import energy, saving money on a larger scale and boosting the economy.
   
4. Increasing Security: Over-reliance on limited or imported energy sources makes a country vulnerable. Conserving energy and developing local renewable sources makes a nation more energy independent and secure.
   
5. Facilitating Renewable Energy Transition: Using less energy overall makes it easier to switch to renewable sources like solar and wind. It reduces the amount of new renewable energy infrastructure needed and can help manage the variability of these sources.

G. Large – scale hydroelectric projects have an impact on the environment. Search the Internet to find out how these projects affect the flora and fauna, and people’s lives in the area.

Ans:

Do it yourself.

H. Picture Study
Look at the picture and answer the following questions.

Question 1.
What type of energy is generated at this site?
Ans:
Wind Energy.

Question 2.
Where is this type of energy generated in India?
Ans:
India has several wind forms especially in the South.

I. Map work.
On the outline map of India given here, mark and name any five hydroelectric projects in India.
Ans:
The five hydroelectric projects in India are :

1. Lower Jhelum
2. Salal
3. Ramganga
4. Harduaganj
5. Sardar Sarovar

LET’S DO SOMETHING

Where does your water come from ?
Each city has a different source for its water supply like reservoirs, rivers or wells. Find out where your town or city gets its supply of water from.
Ans:

Being an AI, I don’t have a physical presence or a personal water source like a city. My operations rely on computer systems housed in data centers, which use water for cooling. The origin of this water varies depending on the data center’s location.

However, for Pune, Maharashtra, India, the city’s primary water supply comes from surface water, mainly stored in several dams:

• Khadakwasla Dam: This is a key reservoir providing water to Pune and its suburbs.
• Panshet Dam: Situated upstream, it contributes water to the Khadakwasla reservoir.
• Varasgaon Dam: Also located upstream, it adds to the water supply of Khadakwasla.
• Temghar Dam: Another surface water source that helps meet Pune’s needs.
• Mulshi Dam: Located on the Mula River, this dam is also a significant source of water for the city.

In the past, groundwater from wells was also utilized in Pune and still serves as a supplementary source. However, due to population growth and urbanization, the city now largely depends on the water stored in these dams, which is managed, treated, and distributed by the Pune Municipal Corporation (PMC).