Câu hỏi:

Read the following passage and mark the letter A, B, C, or D to indicate the correct answer to each of the questions. 

     The coming decades will witness considerable changes in the way energy is supplied and utilized. In some major oil-producing nations "peak oil" has already been reached, and they are unable to manufacture so much oil as in the past. Consequently, many countries are focusing on the switch to a low carbon economy considering global warming as well. This transition will lead to major changes in the supply and use of electricity. To meet these challenges, countries are investing in Smart Grid technology. 

     Smart Grid technology basically involves the application of a computer system to the electricity network.  The computer system can be used to collect information about supply and demand. With better information about electricity demand, the network will be able to increase the amount of electricity delivered per unit generated, leading to potential reductions in fuel needs and carbon emissions. 

     Smart Grid technology brings benefits to the consumer too. They will be able to collect real-time information on their energy use. Varying tariffs throughout the day will give customers the incentive to use appliances at times when supply greatly exceeds demand, leading to great reductions in bills. Smart meters can also be connected to the internet or telephone system, allowing customers to switch appliances on or off remotely. 

     However, we are facing a range of challenges related to these changes. The first involves managing the supply and demand. Sources of renewable energy such as wind, wave and solar are notoriously unpredictable, and nuclear power, which is also set to increase as nations switch to alternative energy sources is inflexible. With oil and gas, it is relatively simple to increase the supply of energy to match the increasing demand during peak times of the day or year. With alternative sources, this is far more difficult, and may lead to blackouts or system collapse. Potential solutions include investigating new and efficient ways to store energy and encouraging consumers to use electricity at off-peak times. 

     Another problem is that a number of renewable power generation sources are located in remote areas, such as windy uplands and coastal regions, where there is a lack of electrical infrastructure. New infrastructures therefore must be built. Thankfully, with improved smart technology, this can be done more efficiently by reducing the reinforcement or construction costs. 

     Though Smart Technology is still in its infancy, pilot schemes to promote and test it are already underway. Consumers are currently testing the new smart meters which can be used in their homes to manage electricity use. There are also a number of demonstrations being planned to show how the smart technology could practically work and trials are in place to test the new electrical infrastructure. Cities are prime candidates for investment into smart energy, due to the high population density and high energy use it is here where Smart Technology is likely to be promoted first utilising a range of sustainable power sources, transport solutions and an infrastructure for charging electrically powered vehicles. The infrastructure is already changing fast. By the year 2050, changes in the energy supply will have transformed our homes, our roads and our behavior. 

According to paragraph 1, what has happened in some oil producing countries?