The status of renewable energy in Norway
In Norway, 98 percent of the electricity production come from renewable energy sources. Hydropower is the source of most of the production. The usage of electricity has increased in line with the modernization and economic growth. The production of 98 percent of all electricity from renewable sources puts in a unique position in both a European and global perspective. The production of Electricity is for the most part based on flexible hydropower, but both wind and thermal energy contributes to the electricity production. The dominant role of hydropower in the electricity production makes sufficient precipitation and inflow to the dams and reservoirs. At the same time, having flexibility in the power production makes it possible to both export and import power to or from neighboring countries.
(Ministry of Petrolum and Energy, https://www.regjeringen.no/en/topics/energy/renewable-energy/renewable-energy-production-in-norway/id2343462/)
The basic principle of hydropower is using water to drive turbines. Hydropower plants consist of two basic configurations: with dams and reservoirs, or without. Hydropower dams with a large reservoir can store water over short or long periods to meet peak demand. The facilities can also be divided into smaller dams for different purposes, such as night or day use, seasonal storage, or pumped-storage reversible plants, for both pumping and electricity generation. Hydropower without dams and reservoirs means producing at a smaller scale, typically from a facility designed to operate in a river without interfering in its flow. For this reason, many consider small-scale hydro a more environmentally-friendly option. (international renewable energy agency, http://www.irena.org/hydropower)
The trend of renewable energy production on installed capacity of Norway starting 2005 to 2016 is plotted as given below. Since hydropower take the largest pat of the renewable energy production of Norway, the trend of it also given on the figure.
Figure: Trends of renewable energy in Norway
(international renewable energy agency (http://www.irena.org/hydropower)
The trend of Hydropower energy production of Norway starting 2005 to 2016 is plotted as given below Figure Trends of Hydropower energy in Norway
(International renewable energy agency, http://www.irena.org/hydropower)
European renewable energy compared to Norway
Europe has an abundance of renewable energy sources, and its countries in recent years have become leaders in driving the deployment of renewable technologies. Europe is rapidly stepping away from the reliance of fossil fuels towards energy from renewable sources, wind and solar in particular. When looking at Norway’s Green Battery potential, not all renewable energy production in Europe is relevant. This is because the transport costs and energy losses increase the further away from Norway we get. Sweden, Denmark, England, Scotland, Netherlands and Germany are the most relevant sources for renewable energy storage. Germany was the first country to develop scenarios for how Norwegian reservoirs could balance the renewable energy production. England and Scotland are also planning on constructing numerous large-scale offshore wind farms, which means that they are in critical need of balancing power through storage. In fact, a recent study from the UK identifies Norway as the preferred solution to this problem.
Figure European energy production installed capacity 2005-2016
General over view of hydropower schemes
Hydropower can be generated wherever a flow of water descends from a higher level to a lower level. The difference between the two water surface elevations is referred to as head. Head can exist in nature, for instance when a stream runs down a steep hillside or when a sharp change in elevation creates a waterfall in a river. However, head can also be created artificially by constructing a weir or dam; the dam creates a barrier to water flow, raising the upstream water level to the desired elevation. As a result of elevation differences gravitational potential energy is stored in the water; this energy can be exploited by installing turbines and generators. Water flow moves the turbine blades, thereby converting water’s potential energy into kinetic energy. The turbine rotation forces the generator rotator to spin around the stator thereby converting kinetic energy first to mechanical energy, and then to electrical energy. This concept is depicted below in a schematic illustration.
Sketch of a typical HPP with dam used for creation of head.
(Hydroelectric power, A Gide for developer and investors, https://www.ifc.org/wps/wcm/connect/06b2df8047420bb4a4f7ec57143498e5/Hydropower_Report.pdf?MOD=AJPERES)
Energy demand of Norway
The Norwegian economy is growing every year and continued to grow after that, measured as the overall gross domestic product (GDP). The growing of economy become increase the consumption of energy. The demand of the country energy increases in different sector. The industry sector uses about one third of the final energy in Norway. In general energy use of industry is highest during the year 2000 to 2008 and there is some decrease in 2009 and 2010. In 2015 industry is the largest energy consuming sector, the consumption increases to 40% of the total energy. In the case of house hold energy uses increase from year to year. From the period of 1990 to that of 2010 the use of energy in the house hold increases from 41TWh to 51TWh. In the year of 2015 Energy consumption in the house hold or residential sector increased slightly by 0.2% over the past decade. The other one is in the transport sector the total energy consumption in the transport sector has increased from 45TWh in 1990 to 62TWh in 2010. In recent decades, energy use in transport has grown faster than in any other sector. In 2015, transport consumed 24% of the total final consumption.
The energy demand of Norway increased in all sector as we see from the year of 1900 to 2015 the consumption rate increases in all sector. The Norwegian energy consumption by the year 2012 in different sector indicated below on the chart.
(IFE (institute of energy technology) ,energy policies of IEA countries, https://www.ntnu.no/documents/7414984/0/IFE-report+Future+energy+demand.pdf/6c210f3a-7511-421b-96e9-fe21c92803f1, http://www.iea.org/publications/freepublications/publication/EnergyPoliciesofIEACountriesNorway2017.pdf)
Power Demand Variations and Balancing the power systems
Changes in electricity demand levels are generally similar and have different variations pattern.
Daily patterns: Demand levels rise throughout the day and tend to be highest during a block of hours referred to as “on-peak,” which usually occurs between 7:00 a.m. to 10:00 p.m. on weekdays.
Weekly patterns: Demand levels are generally lowest between 10 p.m. and 7 a.m. and on weekends. This is usually referred to as “off-peak”.
Seasonal patterns: Demand levels during the summer and winter months tend to be higher than demand levels during the fall and spring seasons when system demand for space conditioning (heating or cooling) is low. The annual peak of hourly, daily, and monthly demand typically occurs during the winter or summer. In Norway, annual peak occurs during winter.
To balance these variations in load, Load balancing is done. Load balancing refers to the use of various techniques by power stations to store excess power during low demand periods and release it when demand rises.
(Loring Chien,(Jun 20117), ‘why there is load variation in power systems’)
Lecture Slide, Prof. Brian Glover, (Jan, 2018)
Base load supply
Base load plant is an energy station which is used for the production of base load supply. Baseload plants are the production facilities used to meet some or all of a given region’s continuous energy demand, and produce energy at a constant rate, usually at a low cost relative to other production facilities available to the system. Nuclear plants, Coal fired plants, Oil fired steam generators, Thermal sources such as biogas, bagasse, combined heat and power, Gas fired combined cycle (gas turbines and steam turbine working in combination), Multi-purpose hydro e.g. combined with irrigation dams or water supply can be some of the base load plants. Baseload plants typically run at all times through the year except in the case of repairs or maintenance. These plants are often designed for relatively high efficiency, and may be combined cycle plants, but may take several days to start up and shut down.
(Energy Dictionary, energyvortex.com)
Hydropower as a flexible Load following Power plant
Load following power plant is a power plant that adjusts its power output as demand for electricity fluctuates throughout the day. Load following power plants run during the day and early evening. They either shut down or greatly curtail output during the night and early morning, when the demand for electricity is the lowest. The exact hours of operation depend on numerous factors. One of the most important factors for a particular plant is how efficiently it can convert fuel into electricity. The most efficient plants, which are almost invariably the least costly to run per kilowatt-hour produced, are brought online first. As demand increases, the next most efficient plants are brought on line and so on.
Gas turbine power plants, Diesel and gas engine power plants, Hydropower with daily regulating reservoir pondage or larger reservoir, Pump storage plants, are the typical examples of load following power plants. Hydropower could be one of the most flexible power plant with the demand variation in load. Hydroelectric power plants can operate as base load, load following or peaking power plants. They have the ability to start within minutes, and in some cases seconds. Lakes and manmade reservoirs used for hydropower come in all sizes, holding enough water for as little as a one-day supply, or as much as a whole year’s supply. A plant with a reservoir that holds less than the annual river flow may change its operating style depending on the season of the year. For example, the plant may operate as a peaking plant during the dry season, as a base load plant during the wet season and as a load following plant between seasons. A plant with a large reservoir may operate independently of wet and dry seasons, such as operating at maximum capacity during peak heating or cooling seasons. (Renewable and Efficient Electric Power Systems By Gilbert M. Masters p. 140)
Pump Storage Power Plants for supplying fluctuating energy demand
The EU has agreed to undertake major cuts in greenhouse emissions and to increase power generations from renewable energy sources. Wind power will make up much of Europe’s future Power generation. Several major projects are already being constructed and planned on the continent in the north sea and along the UK coast line. Wind power can only be generated when the wind is blowing and variations are considered over time. These variations do not always correspond with the consumption. A large share of wind power would represent a major challenge to stability of the transmission systems and the security of supply for the consumers. There is a need for backup capacity in order to generate power in days with no wind and high demand. There is also a need of storage capacity for surplus power on days with strong wind and low demand.
In Norway, with its long history of hydropower generation, we find half of Europe’s reservoir capacity. New pump storage power plants in connection with existing reservoir could be a part of solution in securing a reliable energy system. On windy days surplus power could be used to pump water from low to high altitude reservoir. This water could in turn be released to generate power on days when demand is high and wind levels are low. The cycle can be repeated over and over again. In order to use Norwegian Hydropower as rechargeable batteries for the European power supply more transmission capacity must be established between Norway and the major European consumption areas. Pump storage power solution must be developed in such a way that the environmental impacts are reduced to a minimum. The climate threat is a global challenge, the further development of Norwegian Hydropower can contribute a more reliable and a cleaner European energy supply.
(statkraft, pumped-storage-hydropower, statkraft.com/energy-sources/hydropower)
Nordlink, The green link
Nordlink is a proposed subsea cables between Norway and Germany over 500km which has a capacity of 1400 MW and an operational voltage of 500 KV. The new connection would be tested in late 2019, and operational in 2020. Different patterns of generation with large thermal and growing wind power on the Continent versus large hydro capacities in Northern Europe are expected to offer mutual benefits, however on the other hand there may be some risk of worsening existing bottlenecks in the grid.
(Statnet, nord.link, “Status of transnational project”)
Connecting Norwegian hydropower to German wind energy will be benefitial for both countries. When for instance a surplus of wind energy is produced in Germany, this can be exported to Norway via NordLink. The water reservoirs in Norway will then function as natural storage for wind energy by retaining the water in the reservoirs. Likewise, Germany can import the renewable Norwegian hydropower when demand is high. (statnett,Feb-2015,”Green light for Nordlink”)