Wednesday, 14 November 2018 L.O: To know about different types of alternative fuels and to understand the advantages and disadvantages of using these fuels.

Developing Alternative fuels Some alternative fuels have already been developed, and there are others in the pipeline (so to speak). Many of them are renewable fuels so, unlike fossil fuels, they won't run out. However, none of them are perfect — they all have pros and cons.

Biofuels… … are fuels that are made from plant material. (There are two types of biofuel you need to know about — ethanol and biodiesel.)

The next few slides will be about 3 different types of fuels and their advantages and disadvantages. Remember to make notes on these… Make notes!

Can you spot any advantages or disadvantages of ethanol yet? Ferment and distil sugars to make ethanol, then blend with gasoline for best results Separate starch into simple sugars Harvest Plants (e.g. corn) Ethanol Ethanol is made by fermentation of plants and is used to power cars in some places. It's often mixed with petrol to make a better fuel. Can you spot any advantages or disadvantages of ethanol yet?

Ethanol Advantages Disadvantages The CO2 released when ethanol is burnt was taken in by the plant as it grew, so it's ‘carbon neutral'. The only other product when ethanol burns is water and the process of making ethanol doesn't require much energy, so ethanol is better for the environment than fossil fuels. Ethanol is a renewable resource because it's made from plants. Growing the crops to make ethanol is labour intensive so provides employment for local people. Engines need to be converted before they'll work with ethanol fuels. Ethanol fuel isn't widely available. There are worries that as demand for it increases farmers will switch from growing food crops to growing crops to make ethanol — this will increase food prices.

Can you spot any advantages or disadvantages of biodiesel yet? Use to run a diesel engine Mix with ordinary diesel fuel Make vegetable oil Biodiesel Biodiesel can be produced from vegetable oils such as rapeseed oil and soybean oil. It can be mixed with ordinary diesel fuel and used to run a diesel engine. Can you spot any advantages or disadvantages of biodiesel yet?

Biodiesel Advantages Disadvantages Like ethanol, biodiesel is ‘carbon neutral', renewable and provides jobs for local people. Engines don't need to be converted before they can run on biodiesel. Biodiesel produces much less sulfur dioxide and ‘particulates' than ordinary diesel or petrol. We can't make enough to completely replace diesel. Biodiesel is expensive to make It could increase food prices like using more ethanol could.

Hydrogen Gas Hydrogen gas can also be used to power vehicles. You get the hydrogen from the electrolysis of water — but it takes electrical energy to split it up. This energy can come from a renewable source, e.g. solar. Electrolysis of water: splitting water up into hydrogen and oxygen using electricity

Hydrogen Gas Advantages Disadvantages Hydrogen combines with oxygen in the air to form just water — so it's very clean. The hydrogen gas comes from water and there's lots of water about. You need a special, expensive engine to use hydrogen as a fuel. Hydrogen isn't widely available as a fuel. You still need to use energy from another source to make it. Hydrogen's hard to store because it is extremely flammable.

Make sure that you have the advantages and disadvantages of each fuel noted down in your book. For example, this is a disadvantages of one of the 3 fuels. Which one is it? Click on the correct arrow! Hydrogen Gas Biodiesel Ethanol BIODIESEL ETHANOL HYDROGEN You still need to use energy from another source to make it.

Questions Fact Recall Application What is a biofuel? Give two examples of biofuels. Give one advantage and one disadvantage of using ethanol as a fuel. What is biodiesel made from? A distribution company wants to reduce its impact on the environment. Its fleet of distribution vans currently runs on diesel fuel. Suggest a way that this company could become more environmentally friendly without having to replace all of the vans it already has. A company makes hydrogen gas from the electrolysis of water. The electricity needed for this process comes from a fossil fuel power station. The company claims that their hydrogen is a completely clean fuel because the only product formed when hydrogen burns is water. Explain why this claim is incorrect. What could the company do to make its hydrogen a completely clean fuel?

Answers Fact Recall A renewable fuel made from plant material. Examples include ethanol and biodiesel. Advantages: e.g. Ethanol is carbon neutral. / The only products produced when ethanol burns are carbon dioxide and water. / Ethanol is a renewable fuel. / Growing crops for ethanol provides jobs. Disadvantages: e.g. Engines need to be converted before they can use ethanol fuels. / Ethanol fuel isn't widely available. / If demand for ethanol increases, farmers may switch to growing crops for ethanol instead of crops for food and food prices could increase. Vegetable oils (e.g. rapeseed oil and soy bean oil).

Answers Application The company could use biodiesel to run their vans, rather than diesel. You couldn't give using ethanol or hydrogen gas as an answer to this question because the company would have to replace their vans with vans that are adapted to use ethanol or hydrogen gas as fuel. The energy to make the hydrogen comes from burning fossil fuels and burning fossil fuels releases carbon dioxide and other pollutants. They could use electricity from a renewable energy source (e.g. solar power) to make their hydrogen.