The safety, cost-effectiveness, cleanliness, and renewability of energy sources can vary based on factors such as technology advancements, geographical location, and specific applications. As of my last update in September 2021, I'll provide you with information about energy sources that are generally considered safe, cost-effective, clean, and renewable:

Safety and Cost-Effectiveness: Natural Gas

Natural gas is often considered one of the safest and cost-effective energy sources. It produces fewer emissions compared to coal and oil, resulting in lower air pollution and greenhouse gas emissions. Modern natural gas power plants are relatively efficient and have a good track record in terms of safety. However, it's important to note that safety can vary depending on factors such as extraction methods (fracking), transportation, and proper facility management.

Cleanest and Most Renewable: Solar and Wind Energy

Solar and wind energy are widely regarded as the cleanest and most renewable energy sources. They produce minimal or zero greenhouse gas emissions during operation, making them environmentally friendly. They are also virtually inexhaustible and don't rely on fuel extraction or depletion. The ongoing advancements in solar panel and wind turbine technologies have led to improved efficiency and decreased costs, making these sources increasingly competitive.

However, it's essential to recognize that all energy sources have their own advantages and disadvantages:

• Nuclear Energy: While nuclear energy generates large amounts of electricity with minimal greenhouse gas emissions, concerns about nuclear waste disposal and potential safety issues can arise.
• Hydropower: Hydropower is a reliable and renewable source, but its environmental impact can be significant due to dam construction and disruption to aquatic ecosystems.
• Biomass: Biomass energy utilizes organic materials, but its impact depends on sustainable sourcing and ensuring that it doesn't compete with food production.
• Geothermal: Geothermal energy is clean and renewable, but its availability depends on geological factors and location.

The energy landscape continues to evolve, with ongoing research and innovation leading to improvements in various technologies. It's important to consider a mix of energy sources based on local conditions, energy demands, and environmental goals. Always assess the latest information and consult experts when making decisions about energy sources for specific applications.

Dr Gaurav H Tandon thank you for your contribution to the discussion

Yet, according to the International Energy Agency, as cited by Energy Intelligence, even when factoring in the cost of intermittency, solar remains cheaper than all other sources of energy, and specifically those generated using oil, gas, and coal.Solar and wind energy have continued to occupy the top spots in terms of the cheapest renewable energy sources. Both energy sources cost significantly less than fossil fuel alternatives and continue to become more affordable every year.Wind is now the cheapest source of renewable energy in India. While the death toll, direct and indirect, of renewable energy is much higher compared to that of nuclear, this is mostly due to one single catastrophic event. Overall, renewable energy should be considered safer because there is no risk of long-lasting radioactive contamination of the environment. Coal is the most important and abundant fossil fuel in India. It accounts for 55% of the country's energy need. The country's industrial heritage was built upon indigenous coal. Renewable Power to be 12% to 29% cheaper than Fossil Fuel in India, China, Australia: Report. India, China, and Australia are the top three countries where renewable energy is cheaper by 12% to 29% compared to the lowest-cost fossil fuel. These resources of energy can be naturally replenished and are safe for the environment. Examples of renewable sources of energy are: Solar energy, geothermal energy, wind energy, biomass, hydropower and tidal energy. India aims to achieve net zero emissions by 2070, and renewable energy is key to achieving this goal. Solar energy accounts for a significant share of India's renewable energy portfolio, and innovations in solar energy, such as rooftop solar systems and floating photovoltaics, are gaining ground. Solar power is one of the cleanest forms of energy because it does not emit any greenhouse gases. Out of all energy resources, we consider green power as the cleanest form of energy. So, if we were looking at clean energy on a spectrum, these would be farthest from “dirty” or emissions-heavy energy. Solar energy, much like wind, is one of the most sustainable energy sources currently available. In fact, given its modular and scalable nature where it can be utilized as part of massive solar fields or mounted on individual homes it may be the most practical form of sustainable energy in use today. Hydropower currently is the largest source of renewable energy in the electricity sector. It relies on generally stable rainfall patterns, and can be negatively impacted by climate-induced droughts or changes to ecosystems which impact rainfall patterns.