Anthony Meaney
Ireland’s energy consumption and the environmental impact, If Ireland was to reduce its fossil fuel consumption in the generation of electricity by 10% and use renewable energy sources what would be the economic implications and the environmental impact.
Abstract: With fossil fuels rising and Ireland signed up to CO2 emissions reduction treaties, this report investigates the current trend of global markets and then investigates Irelands usage of both fossil fuels and renewable energy usage for the generation of electricity. To comply with EU CO2 reduction treaties and to counter the rise in prices of fossil fuels this report looks at how much CO2 can be reduced and the cost that would be saved if Ireland was to reduce its consumption of fossil fuels for electricity generation and increase its renewable energy generation by 10%. This report also looks into several key renewable energies that Ireland is currently engaged in developing and reports on what renewable energies Ireland should look to investing in the future.
Key words – Renewable Energy, Ireland Energy Usage, Ireland Emission Reduction, Increased Renewable Energies in Ireland.
1.0 Introduction – World Market
2.2.3. Shannon Liquefied Natural Gas
2.6.1.1 Electricity Generation Efficiency
2.6.4 Electricity Infrastructure and Investment
3.1.3 Advantages / Disadvantages
3.2 Marine Energy: Tidal and Wave Energy
3.4.2 Liquid biofuel energy crops
4.1 Total amount of Energy used to generate Irelands electricity demands
1.0 – Introduction – World Market
Energy prices have been increasing due to increasing demands on fossil fuel. Ireland is no exception to this and because Ireland imports over 80% of its fossil fuels for energy generation, as this is a cost analysis as well as an environmental analysis world energy markets and trends must be investigated. Ireland using the combination of hydro and wind energy for the generation of 16% of Ireland consumption by 2020 in Directive (2009/28/EC)
1.1 World Market Oil Demand
Oil demand is driven by economic growth. The economic recession caused an overall reduction in the global demand in 2008 and 2009. Demand increased, however, in non OECD (Organization for Economic Co-operation and Development), driven by continued growth in transport activity. Total oil demand in 2010 increased by 86.7 million barrels per day. In 2011 this is expected to rise to 89.2 million barrels per day. [1]
Fig. 1 - Global Oil Demand – SEAI
Fig 2 - Global oil market developments - world oil production (million barrels per day) - SEAI
1.1.1 Oil Prices
Since 2000, oil prices grew steadily and since 2004 have not returned to the cheap $30 per barrel. Oil prices post 2005 were driven by rapid economic growth in China and India in particular, without an accompanying rise in supply, and then peaked in July 2008 at more than $140 per barrel. The extent to which the oil price rise contributed to the global economic recession in 2008 and 2009 has not been quantified. The effect of the recession on oil prices is, on the other hand, clearly visible in Figure 4, with the dramatic reduction in price (to as low as $34 per barrel in December 2008) due to falling oil demand. From mid-2009 to mid-2010, oil prices were relatively stable at $70 - $80 per barrel.
As previously mentioned, economic recovery, together with tightening of oil supply, has led to a significant price increase since October 2010 and oil has remained above $100 per barrel since February 2011. This increase in oil prices now poses a threat to a fragile global economy. [1]
Fig. 3 – European crude oil spot prices 2000 – 2011 –SEAI
1.2. World Market Gas Demand
The major recent developments in gas supply are a) the notable expansion of unconventional North American gas and b) the growth of liquefied natural gas capacity. Unconventional gas includes shale gas, coal bed methane, tight gas (from low permeability reservoirs) and methane hydrates
The International Energy Agency estimates that proven resources amounted to 184 Tm3 by the end of 2008 and that cumulative production (since gas production first started) by the end of 2009 amounted to about 90 Tm3. Estimates for remaining recoverable resources of conventional gas amount to 404 Tm3. The majority of these resources (both proven and remaining recoverable) are in the Middle East and Russia. Unconventional gas estimates excluding methane hydrates, are estimated to be 900 Tm3.
Fig. 4 - Schematic geology of natural gas resources. –SEAI
The production of shale gas in the USA rose from 12 Gm3 in the year 2000 to 45 Gm3 in 2009 reversing the downward trend on overall gas output. This largely eliminated the requirement for liquefied natural gas imports into the USA and along with the global recession, contributed to a global surplus gas supply.
The other key development impacting on gas security is the increase in capacity and production of liquefied natural gas, which has the distinct advantage of being readily transportable by ship, removing some of the constraints of pipeline gas. Preliminary figures show that global trade shot up to 220 million tonnes (300 Gm3) in 2010, a 20% increase from 2009. The main supplier of liquefied natural gas is Qatar, while demand is primarily coming from Asia and Europe. As well as trade increasing last year, a number of new liquefied natural gas projects were under construction everywhere from Angola to Algeria, but most notably in Australia, which will start producing significant supplies over the medium term. [1]
1.2.1 Gas Prices
Gas prices have been coupled to oil prices and even now nearly half of OECD gas demand is priced directly off oil, with varying time lags and linkages. In 2009, as oil prices increased, these markets, including Japan, Korea, and most of continental Europe saw prices averaging about $9/Mbtu (Million British Thermal Units = 293 kWh). In North America and the United Kingdom (and hence also Ireland), prices averaged less than half this level, on an energy basis around one‐third that of oil This resulted in gas prices in Ireland being lower than the EU average during 2009. In 2010, this situation changed however, as gas prices in the USA and UK decoupled, with USA prices remaining low and UK prices increasing and realigning with European prices, as liquefied natural gas imports into Europe increased steadily. [1]
Fig. 5 - Natural gas prices over the past 10 years – Canada National Energy Board
2.0 Introduction - Ireland
Ireland relies heavily on fossil fuels (95% of total primary energy requirement) and has 88% import dependence for all fuels. Diminishing supplies of oil and gas in the EU and OECD will impact on Irish energy security. Diversifying the fuel mix enhances energy security by reducing demand for imported fossil fuels and also the exposure to their variations in price. Other ways to enhance energy security include improving existing energy infrastructure, for example introducing more gas storage facilities and electricity grid upgrades and interconnection. The contribution from renewables and wastes is the only increasing indigenous energy source and was the most significant indigenous energy source in 2009. [1]
2.1 Oil
Ireland’s consumption of Oil accounts for just over half of the primary energy consumption with 52% in 2009 and 60% of total energy imports. Ireland’s oil dependence (as a proportion of primary energy supply) was fifth highest in the European Union in 2009. Transport is the largest end use of energy in Ireland, accounting for 41% of total final consumption in 2009. There is a 100% import dependence on oil for the transport sector. [1]
2.1.1 Oil Prices
Oil is a commodity traded on the international market and crude oil prices are dependent on market forces. The market forces that principally influence oil prices are supply and demand, with global growth patterns and political stability factors that may impact on the supply or demand. As Ireland is neither a producer nor a significant world player in terms of demand, it cannot influence the price of oil, in spite of significant import dependence.
Crude oil prices increased from $30 per barrel in 2004 to a peak of $144 per barrel on July 11th 2008, doubling between July 2007 and July 2008. During the first semester (S1) of 2008, nominal crude oil prices increased by 39%. After July 2008, there was a sharp decline in the price of crude oil to a low of around 34 $/barrel in late December 2008. Average oil prices during the second half of 2009 were 71 $/barrel and 97 $/barrel for the whole of 2008. During 2009 as a whole, the average oil price was 62 $/barrel and in 2010 this increased to 80 $/barrel. Oil prices have increased again in 2011 with the average price between January and mid-April at 108 $/barrel. [1]
2.2 Gas
The dependence on natural gas has increased from 15% of total primary energy in 1990 to 29% in 2009. Most natural gas used in Ireland is imported (93% in 2009). Electricity generation in Ireland relies heavily on natural gas, with over 60% of electricity generated in 2010 from natural gas. [1]
2.2.1 Corrib Gas Field
According to the International Energy Agency, the Corrib gas field is expected to start commercial production in 2012/13. Corrib gas production is anticipated to meet 73% of Ireland’s annual demand in this first year. The production profile is quite short, however, and is expected to decline within 6 years of its commencement. Initial peak production of Corrib is forecast to be 9.5 Mm3/d in 2013 but production is expected to decline to 4.2 Mm3/d by 2018/19. This compares with 2009 annual demand of 14 Mm3/d. [1]
2.2.2 Gas Storage
Ireland has one gas storage facility - off the south west coast at Kinsale. This facility has the capacity (depending on the levels of gas held in storage at any given time) to supply 48% of protected customers for up to 50 days, which equates to 10% of annual demand. The Kinsale facility currently has a working volume of circa 218 million cubic metres (Mm3), which is equivalent to approximately 4.2% of Ireland’s annual gas consumption in 2009. It has a maximum withdrawal rate of 2.5 Mm3/day and a maximum injection rate of 1.6 Mm3/day. Gas imports from Great Britain are used to refill the storage facility at Kinsale in addition to site production. The operator of the facility is currently examining the feasibility of developing additional storage at the site.
Islandmagee Storage Limited (formerly Portland Gas NI Ltd) proposes to develop a 500 Mm3 salt cavity storage facility under Larne Lough. The company has completed seismic testing and successfully submitted a planning application to the relevant authorities in Northern Ireland. Islandmagee Storage plans gas operations to commence in 2015.
BGE (NI), a subsidiary of Bord Gais and Storengy, have established the North East Storage project14, to determine if there are subterranean salt layers present to the southwest of Larne, which could potentially be used for underground natural gas storage. A seismic survey and analysis of survey data were completed in early 2010 and a test drill was carried out in early 2011 to complete the technical feasibility stage of the project. The initial results have indicated that suitable subterranean salt layers are present approximately 1500m (one mile) below the surface. [1]
2.2.3. Shannon Liquefied Natural Gas
Shannon liquefied natural gas proposes to construct the country’s first liquefied natural gas terminal in the Shannon estuary. This project has received full planning permission. In December 2009, the terminal developers received the authorisation from the Commission for Energy Regulation to construct a gas pipeline, which will connect the proposed liquefied natural gas terminal to the national gas grid. This project is expected to be developed on a phased basis. The facility is expected initially to have a maximum output of 10.7 Mm3/day with output reaching 26.8 Mm3/day at maximum production. Phase 1 of commercial operations is expected to commence in 2015/16. The liquefied natural gas project has the potential to add diversity to Irish gas supplies. [1]
2.2.4 Natural Gas Prices
Natural gas prices to industry in Ireland were 17% higher in real terms in the fourth quarter (Q4) of 2010 than in the year 2005. The UK end-user gas price forecast is the National Balancing Point (NBP - a virtual trading location for UK gas). Price forecasts are from the UK National Grid Ten Year statement. It predicts a doubling in the National Balancing Point price between 2009 and 2025. While the exact price may not be realised, the trend of a constant increase in gas prices is significant. Similar to oil prices the price of gas is predicted to continue rising in the foreseeable future.Ireland currently relies on the UK for all natural gas imports. [1]
2.3 Import Dependency
Since the mid-1990s import dependency has grown significantly, due to the increase in energy use across all sectors but particularly in transport. This increase in demand together with the decline in indigenous natural gas production at Kinsale since 1995 and decreasing peat production has led to the increase in import dependency. Domestic production accounted for 32% of Ireland’s energy requirements in 1990 but in 2009 that had reduced to 11%, resulting in Ireland’s import dependency being at 89% in 2009. [1]
Fig. 6 – Import dependency of Ireland and the EU 1990 – 2009 - SEAI
The decline of indigenous natural gas reserves at Kinsale is also indicated by the growth in imported natural gas in the latter part of the decade. This is largely the result of increased usage of gas in electricity generation. Coal imports have remained stable over the period reflecting the base load operation of Moneypoint electricity generating plant although they fell by 19% in 2009. In 2009, oil, gas and coal accounted for 60%, 30% and 9% of net imports respectively while electricity and renewables (biofuels and wood pellets) accounted for the remaining 1% of net imports in 2009. [1]
2.4 Indigenous Energy Sources
Ireland is not endowed with significant indigenous fossil fuel resources and has to date not harnessed significant quantities of renewable resources, although there has been strong growth in renewables in recent years from a small base. The reduction in indigenous supply of natural gas is clearly evident from the graph as is the switch away from peat. Production of indigenous gas decreased by 83% over the period since 1990, peat by 59% while renewable energy in contrast increased by 261%. Indigenous production peaked in 1995 at 4.1 Mtoe and there has been a 63% reduction since then.
Of the indigenous energy production in 2009 renewable energy was responsible for 40%. Therefore the decline in indigenous sources of energy has been halted by the use of renewables. Peat accounted for 38% of all indigenous energy in 2009 and natural gas accounted for 21% of indigenous energy. There was also a small contribution from non-renewable wastes. [1]
Fig. 7 - Indigenous energy sources by fuel 1999 -2009 –SEAI
2.5 Energy Prices
The most significant factor affecting energy prices in Ireland is recent dramatic changes in global oil prices. This has particular effect in Ireland due to Ireland’s high dependence on oil. In addition there is the knock-on impact oil prices have on other energy prices, in particular natural gas. A consequence of the increase in natural gas prices and because of Ireland’s reliance on natural gas for electricity generation, electricity prices have increased.
2.6 Electricity
Ireland uses a lot of different methods for the generation of its electricity demands 57278GWh; these methods are from the burning of fossil fuels to renewable energies.
2.6.1 Electricity Generation
The relative size of the final electricity consumption and the energy lost in transformation and transmission is striking. These losses represent 55% of the energy inputs. The dependence on natural gas in electricity generation in 2010 was 61%. The small, but growing, contribution from renewables is also notable as is the dominance of gas in the generation fuel mix.
In terms of energy security the dominance of gas is a significant risk both to the physical security of supply and also of exposure to price variation. Increasing the share of renewable electricity is a way to reduce the reliance on imported fossil fuels for electricity generation and to reduce the dominance of natural gas in electricity generation. The share of gas generation increased from 28% in 1990 to 61% in 2010. Renewable energy nearly trebled its share, in the context of a doubling of overall gross electricity consumption.
In 2010, renewables accounted for 7.4% of the energy inputs to generate electricity with wind contributing 4.9% of total inputs. Wind accounted for 66% of the renewable energy used for electricity generation in 2010. However it should be noted that variable renewable electricity sources, in particular wind, introduce short term risks to the security of the electricity supply.
Fig. 8 – Energy Flow in the electricity generation and supply – SEAI
The generation of electricity is shown in Fig. 9 by fuel used to generate the electricity and as percentages for the purposes of comparison with the various targets. Renewable generation makes use of wind, hydro, landfill gas, biomass and other biogas and in 2005 accounted for 6.8% of gross electricity consumption. This increased to 14.3% in 2009 but dropped back to 12.9% in 2010. When normalisation is applied to the wind and hydro contributions, to smooth the effects of climatic variation, the renewable generation as a percentage of gross electricity generation was 13.7% in 2009 and 14.8% in 2010. The national target was 15% by 2010 and is 40% by 2020.
Fig. 9 – Energy Flow in the electricity generation – Fuel inputs/electricity outputs – SEAI
Figure 10 shows the growing trend in gross electricity consumption for Ireland over the period 1990 – 2010. It illustrates the changing shares of each fuel/energy source. Gross electricity consumption over the period doubled, as is the growth in gas-generated electricity.
Fig. 10 – Gross electricity consumption by fuel source – SEAI
Table 1 – Gross Electricity consumption percentages by fuel source – SEAI
2.6.1.1 Electricity Generation Efficiency
Generation efficiency is defined as the electricity produced from both thermal and renewable generators divided by the fuel inputs and expressed as a percentage. Supply efficiency is defined as final consumption of electricity, excluding the generation plants’ “own use” of electricity and transmission and distribution losses, divided by the fuel inputs required to generate this electricity and expressed as a percentage. Thus, by definition generation efficiency is always going to be greater than the supply efficiency as the electricity generators’ “own use”, transmission and distribution losses are not considered as losses in the calculation of generation efficiency. Another difference in the calculations is that imports are excluded from the generation efficiency calculation.
From the mid-1990s onwards the influence of the use of higher efficiency natural gas plants and the increase in production from renewable sources are evident. The sharp rise between 2002 and 2004 (from 35% to 40%) is accounted for, principally, by the introduction of new Combined Cycle Gas Turbine plant (392 MW in August 2002 and 343 MW in November 2002), an increase in imports of electricity and the closure of old peat fired stations.
Improvements in efficiency in 2007 were due largely to the commissioning of two further new Combined Cycle Gas Turbine plants, Tynagh (384MW) in 2006 and Huntstown 2 (401 MW), and the increase in renewable electricity. In 2010 two new combined cyclegas turbine units were connected in Cork with a combined capacity of 877 MW. The steam turbine in Marina was also decommissioned and Marina is now operating as an open-cycle gas turbine. While open-cycle gas turbine plants are not as efficient as Combined Cycle Gas Turbine plants, in this case there was an improvement in efficiency through the installation of a new generator. Two open-cycle distillate peaking units in Edenderry, with a total generating capacity of 114 MW, became operational in 2010. These new peaker plants are also an improvement in efficiency compared to reliance on older oil based peakers. ESB Power Generation decommissioned two units at Poolbeg in March 2010, giving a reduction in capacity of 219 MW. This is in addition to a third 242MW units at Poolbeg which was decommissioned in 2007.
As well as the change to more efficient gas plants the increase of renewables in the system has contributed to the overall efficiency improvement. At the end of 2010 the installed wind capacity was 1448 MW. Due to low wind speeds in 2010, resulting in a capacity factor of only 24% as opposed to an average of over 30% for the previous eight years, there was deterioration in efficiency. As 2010 was also a relatively dry year, the hydro contribution was the lowest in twenty years, which also contributed to the efficiency deterioration. [1]
Fig. 11 – Efficiency of electricity generation and supply 1990 to 2010 –SEAI
2.6.2 Electricity Renewables
Ireland generates 14.8% of its energy using renewable energy electoral generation techniques, because of the variability of renewables in the short term conventional plant with flexibility is required for short term energy security in order to integrate more renewables on the grid.
Fig. 12 – Renewable Energy percentage contribution to gross electricity consumption by source – SEAI
Table 2 – Renewable electricity as a percentage of gross electricity consumption – SEAI
The share of electricity generated from renewable energy sources (RES-E) in 2010 was 12.9%. A significant milestone in 2009 was that wind energy accounted for over 10% of all electricity generation. Biomass is a collective term comprising electricity generation from solid biomass, landfill gas and biogas, where landfill gas provides the most significant input. The more than doubling of electricity generation from renewable energy is clearly visible in Figure 37 and is dominated by the growth in wind energy. [1]
2.6.3 Electricity Demand
Electricity demand per capita increased by 65% over the period 1990 to 2010 (2.6% per annum). The impact of the recession can be seen in the significant drop (4%) in consumption per capita between 2008 and 2009.
Fig 13 – Electricity demand per capita
The winter peak figures represent the expected annual peak demands that are forecast to occur in the October to February winter period of each year; for example the 2010 forecast of 4,950 MW is the maximum demand projected to occur in winter 2010/11. The peak for 2010 was 5,090 MW, which occurred on December 21st
EirGrid forecast the transmission demand for three different scenarios, namely: the winter peak demand, the summer peak demand and the summer valley or summer minimum demand. The summer minimum demand is relevant for variable renewable energy as minimum demand periods that occur when the renewable resource is abundant could mean not all the renewable power is required to meet demand. The summer peak refers to the average peak value between March and September. This is typically 20% lower than the winter peak. While the overall grid power flow may be lower in summer than in winter, this may not be the case for flows on all circuits. In addition, the capacity of overhead lines is lower because of higher ambient temperatures, while network maintenance, normally carried out in the March to September period, can weaken the network, further reducing its capability to transport power.
The annual minimum is referred to as the summer valley. Summer valley cases examine the impact of less demand and less generation dispatched. This minimum condition is of particular interest when assessing the capability to connect new generation. With local demand at a minimum, the connecting generator must export more of its power across the grid than at peak times.
Fig. 14 – Transmission peak and valley demand forecast 2010 to 2016
2.6.4 Electricity Infrastructure and Investment
In terms of electricity infrastructure, Ireland relies on an extensive high-voltage transmission network and a medium and low-voltage distribution network to transport electricity domestically. The transmission network, a meshed network of high voltage lines and cables for the transmission of bulk electricity, forms the backbone of the electricity supply system in Ireland. EirGrid is the transmission system operator, responsible for planning and operating the transmission system. The main features of EirGrid’s transmission development plan are:
· Completion of the 220 kV expansion project to Srananagh in the Sligo area to meet demand in the North West and provide an essential route for power flows from future wind generation.
· Expansion of the 400 kV systems to provide necessary bulk transfer capacity out of Dublin and Moneypoint, and between this system and the Northern Ireland system.
· The strengthening of the networks in and around Athlone, Castlebar, Cavan, Cork City, Dunmanway, Galway, Letterkenny, Meath Hill, Newbridge, Tullamore, and Wexford to meet demand.
· Establishment of four new 220/110 kV stations in Kerry, three of which are required to connect renewable generation.
· Connection of nine new distribution system operator stations and connection of nine new thermal generators to the transmission system.
· Facilitating the connection of 1,424 MW of renewable energy from the Gate 2 process and 3,995 MW Gate 3 wind applications.
2.6.5 Interconnection
The electricity network in the Republic of Ireland is interconnected with Northern Ireland. The main interconnector is at the Louth 220 kV station. In addition there are 110 kV connections at Letterkenny in Co. Donegal and Corraclassy in Co. Cavan. The two Transmission System Operators in the Republic of Ireland and Northern Ireland are jointly progressing plans to develop an additional North/South interconnector. This interconnector is due to be completed between 2015 and 2017.
The development of interconnection between the All-Island Electricity Grid system and other grids, for example Great Britain and Europe, is considered necessary in order to facilitate greater amounts of renewable electricity. The East-West interconnector between Ireland and Britain is due to be operational by 2012. Investigations are ongoing into other possible interconnectors to either the UK or France. EirGrid states in its Grid 25 development plan that it is likely there will be at least one other interconnector by 2025. However the likelihood of another interconnector has been questioned given the reduction in electricity demand along with the new economic climate, both due to the recession.
Ireland is also being considered for inclusion in an off-shore super grid along with other northern EU countries and Norway. The envisaged grid would integrate and connect renewable energy production capacities in the Northern Seas with consumption centres in Northern and Central Europe and hydro storage facilities in the Alpine region and in Nordic countries.
Fig. 15 – Flows on the North-South interconnector (Louth-Tandragee 275kV lines)
2.6.6 Electricity Prices
There are a number of components which determine the price of electricity. The generation mix, which is mostly made up of fossil fuels in Ireland, is a critical component. Over 60% of Ireland’s electricity is generated from natural gas; therefore the variability in the price of natural gas significantly impacts on the price of electricity in Ireland.
The wholesale cost of electricity is established by the Single Electricity Market (SEM) and reflects the generators fuel and short term operating costs.
Electricity prices to industry in Ireland were 43% higher in real terms in the fourth quarter (Q4) of 2010 than in the year 2005. Real prices are where the effects of inflation have been removed, essentially a constant price. Electricity prices to households in Ireland were 2% higher in real terms in Q4 of 2010 than in the year 2005. [1]
3.0 Renewable Sources
As seen in table 2, Ireland’s renewable energy generation accounts for 12.9% of the overall generation consumption in Ireland. This is broke down into 2.1% Hydro power, 9.7% Wind power and 1.1% Biomass. All other methods for generation are negligible but can still be investigated for the use in the generation of electricity in Ireland.
3.1 Hydro Energy
Ireland has a large number of hydroelectric dams that produce electricity. These dams produce 605GWh (Table 4) each year. There are several types of hydroelectric dams that are used in the generation of electricity. Ireland uses 2 types of storage capacity, conventional storage e.g. Pollaphuca and pumped storage e.g. Turlough Hill. Hydroelectricity power plants have a more predictable load factor. If the project has a storage reservoir, it can generate power when needed. Hydroelectric plants can be easily regulated to follow variations in power demand.
3.1.1 Conventional Storage
Most hydroelectric power comes from the potential energyof dammed water driving a water turbine and generator. The power extracted from the water depends on the volume and on the difference in height between the source and the water's outflow. This height difference is called the head. The amount of potential energy in water is proportional to the head. A large pipe (the "penstock") delivers water to the turbine.
As these are the most common type of hydroelectric dams a lot of these have been constructed around the world generating different amounts electricity. Ireland’s largest conventional dam is in Ardnacrusha which can generate 85MW. The largest dam to be constructed is the Xiluodu Dam which will be able to generate 64 TWh per year.
Fig. 16 – Cross section of conventional dam
3.1.2 Pumped Storage
Pumped-storage hydroelectricity is used by power plants for load balancing. Energy is stored in the form of water which is pumped from a lower elevation reservoir to a higher elevation. Low-cost off-peak electric power is used to run the pumps. During periods of high electrical demand, the stored water is released through turbines to produce electric power. Although the losses of the pumping process makes the plant a net consumer of energy overall, the system increases revenue by selling more electricity during periods of peak demand, when electricity prices are highest. Pumped storage is the largest-capacity form of grid energy storage now available.
Ireland has 1 pumped storage hydroelectric plant in Turlough Hill which can generate 292 MW at peak demand. Another pumped water storage dam has been commissioned and it is being located at Knocknagreenan, co. Cork which can generate 70MW.
Fig. 17 – 24 hour electricity output of pumped storage hydroelectric dam – Wikipedia
3.1.3 Advantages / Disadvantages
There are several advantages of generating electricity using hydro power there are also some draw backs
Advantages:
· Costs: There is no need for fossil fuels to produce electricity. The major cost is the dam itself and then only a small workforce is needed to run the plant making the project economically viable and usually the initial cost is recouped after 10 – 15 years.
· Hydroelectric dams have a long life span between 50 – 80 years.
· As there are no fossil fuels being burned to generate the electricity CO2 produced only in the construction which makes using hydro power one of the cleanest ways of producing electricity.
Disadvantages:
· Land: Reservoirs needed to hold the amount of water for generation tend to be quite large which lead to vast amounts of land use. This can then affect the ecosystems in which the reservoir is being located. People are also usually displaced if they are living in the proposed reservoirs.
· Siltation: As the rivers flow into the reservoirs silt begins to deposit at the bottom of the dam. This then can build up causing the reservoir to fill up with silt reducing the amount of water available for generation. Also the silt build up can cause more pressure on the dam which can lead to failure. An example of siltation build up is the Glen Canyon Dam. [9]
· Flow shortage: Low river flow can lead to less electricity generation which affect the efficiency of the dam. This can be cause by siltation or by low rainfall amounts.
· Failure Hazard: If a critical fault occurs in the dam this can have catastrophic consequences which can majorly effects on eco systems and towns/ villages below the dam.
3.2 Marine Energy: Tidal and Wave Energy
The movement of water in the world’s oceans creates a vast store of kinetic energy, or energy in motion. SEAI estimate that marine energy can generate 0.92TW/h a year. [10] Ireland is has no marine energy in operation at the moment but the SEAI are currently investigating the potential of harnessing Irelands wave and tidal power at 2 sites at Galway and Belmullet. Information can be found on the SEAI website. [13]
3.2.1 Wave Energy
This energy is not currently a commercial technology, the first experimental wave farm was opened in Portugal, at the Agucadoura Wave Park which could produce 2.25 MW. Waves generate about 2,700 GW of power. Of those 2,700 GW only about 500 GW can be captured with the current technology.
3.2.1.1 Environmental Impact
Noise pollution can have an effect on marine life if not monitored, although the noise and visible impact of each design varies greatly. In terms of socio-economic challenges, wave farms can result in the displacement of commercial and recreational fishermen from productive fishing grounds, can change the pattern of beach sand nourishment, and may represent hazards to safe navigation. [11]
3.2.2 Tidal Energy
Tidal energy uses tide flows to generate electricity. Tides are more predictable than winds. Tidal power has traditionally suffered from relatively high cost and limited availability of sites with sufficiently high tidal ranges or flow velocities, thus constricting its total availability. However, many recent technological developments and improvements, both in design (e.g. dynamic tidal power, tidal lagoons) and turbine technology (e.g. new axial turbines, cross flow turbines), indicate that the total availability of tidal power may be much higher than previously assumed, and that economic and environmental costs may be brought down to competitive levels.{12} The amounts of energy that are being generated by tidal barges at the moment are in the 10MW ranges but there has been a vast amount of tidal projects that are being constructed which can generate up to 1500MW.
3.2.3 Tidal Stream Generators
Tidal stream generators work to a similar way to wind turbines. Tides force the fins to rotate with the fins connected to a generator.
Power from these can be expressed:
Where:
CP = the turbine power coefficient
P = the power generated (in watts)
ρ = the density of the water (seawater is 1027 kg/m³)
A = the sweep area of the turbine (in m²)
V = the velocity of the flow
Fig. 18 - Tidal Stream Generator Schematic - www.reuk.co.uk
3.2.4 Tidal Barrage
A tidal barrage are a dam-like structure used to capture the energy from masses of water moving in and out of a bay or river due to tidal forces. Instead of damming water on one side like a conventional dam, a tidal barrage first allows water to flow into the bay or river during high tide, and releasing the water back during low tide. This is done by measuring the tidal flow and controlling the sliuce gates at key times of the tidal cycle. Turbines are then placed at these sluices to capture the energy as the water flows in and out.
Fig. 19 – Tidal Barrage Schematic - ClimateandFuel.com
3.2.4.1 Enviromental Impact
The placement of a barrage into an estuary has a considerable effect on the water inside the basin and on the ecosystem. Many governments have been reluctant in recent times to grant approval for tidal barrages. Through research conducted on tidal plants, it has been found that tidal barrages constructed at the mouths of estuaries pose similar environmental threats as large dams. The construction of large tidal plants alters the flow of saltwater in and out of estuaries, which changes the hydrology and salinity and possibly negatively affects the marine mammals that use the estuaries as their habitat. [14]
3.3 Wind Energy
Ireland generates 9.7% of its energy using wind energy. This is the largest renewable energy usage for the generating of electricity in Ireland. 1,379 MW of wind capacity has been installed in Ireland at the end of June, 2010. In order to achieve national targets for renewable electricity by 2020 (40%) an estimated 5,500-6,000 MW of wind generation is required.
Wind energy's contribution to Ireland's electricity supply continues to rise with additional capacity. By June 2010 a total of 110 wind farms were metered, bringing the total installed capacity for wind generation to 1,379. In 2009, wind power displaced approximately 1.28 million metric tonnes of CO2 emissions (estimated with reference to the grid average CO2) and primary energy imports of 215,000 metric tonnes of oil equivalent to a nation which is 89% dependent on imported energy supplies. [14]
3.3.1 Wind Turbine
A wind turbine is a device that converts kinetic energy from the wind into mechanical energy. This mechanical energy is used to produce electricity, today's wind turbines are manufactured in a range of vertical and horizontal axis types. The smallest turbines are used for applications such as battery charging or auxiliary power on sailing boats; while large grid-connected arrays of turbines are becoming an increasingly large source of commercial electric power.
3.3.1.1 Vertical Type Wind Turbine
Vertical axial wind turbines have the main rotor shaft arranged vertically. Key advantages of this arrangement are that the turbine does not need to be pointed into the wind to be effective. This is an advantage on sites where the wind direction is highly variable, for example when integrated into buildings. The key disadvantages include the low rotational speed with the consequential higher torque and hence higher cost of the drive train, the inherently lower power efficient cycle and hence the highly dynamic loading on the blade, the pulsating torque generated by some rotor designs on the drive train, and the difficulty of modeling the wind flow accurately and hence the challenges of analyzing and designing the rotor prior to fabricating a prototype.
With a vertical axis, the generator and gearbox can be placed near the ground, using a direct drive from the rotor assembly to the ground-based gearbox, hence improving accessibility for maintenance.
When a turbine is mounted on a rooftop, the building generally redirects wind over the roof and this usually doubles the wind speed at the turbine. If the height of the rooftop mounted turbine tower is approximately 50% of the building height, this is near the optimum for maximum wind energy and minimum wind turbulence. It should be borne in mind that wind speeds within the built environment are generally much lower than at exposed rural site. [15]
Fig. 20 – Vertical Axis Wind Turbine - www.climatelab.org
3.3.1.2 Horizontal Type Wind Turbine
Horizontal-axis wind turbines have the main rotor shaft and electrical generator at the top of a tower, and must be pointed into the wind. Small turbines are pointed by a simple wind vane, while large turbines generally use a wind sensor coupled with a servo motor. Most have a gearbox, which turns the slow rotation of the blades into a quicker rotation that is more suitable to drive an electrical generator.
Since a tower produces turbulence behind it, the turbine is usually positioned upwind of its supporting tower. Turbine blades are made stiff to prevent the blades from being pushed into the tower by high winds. Additionally, the blades are placed a considerable distance in front of the tower and are sometimes tilted forward into the wind a small amount.
Downwind machines have been built, despite the problem of turbulence (mast wake), because they don't need an additional mechanism for keeping them in line with the wind, and because in high winds the blades can be allowed to bend which reduces their swept area and thus their wind resistance. Since cyclical (that is repetitive) turbulence may lead to fatigue failures, most horizontal axial wind turbines are of upwind design.
Turbines used in wind farms for commercial production of electric power are usually three-bladed and pointed into the wind by computer-controlled motors. These have high tip speeds of over 320 kilometers per hour (200 mph), high efficiency, and low torque ripple, which contribute to good reliability. The blades are usually colored light gray to blend in with the clouds and range in length from 20 to 40 meters or more. The tubular steel towers range from 60 to 90 meters tall. The blades rotate at 10-22 revolutions per minute. At 22 rotations per minute the tip speed exceeds 90 meters per second. A gear box is commonly used for stepping up the speed of the generator, although designs may also use direct drive of an annular generator. Some models operate at constant speed, but more energy can be collected by variable-speed turbines which use a solid-state power converter to interface to the transmission system. All turbines are equipped with protective features to avoid damage at high wind speeds, by feathering the blades into the wind which ceases their rotation, supplemented by brakes. [16]
Fig. 21 – Horizontal Wind Turbine - www.ec.europa.eu
3.3.2 Environmental Impact
Wind power consumes no fuel, and emits no air pollutiom unlike fossil fuel power sources. The energy consumed to manufacture and transport the materials used to build a wind power plant is equal to the new energy produced by the plant within a few months. While a wind farm may cover a large area of land, many land uses such as agriculture are compatible, with only small areas of turbine foundations and infrastructure made unavailable for use.
There are reports of bird and bat mortality at wind turbines as there are around other artificial structures. The scale of the ecological impact may or may not be significant, depending on specific circumstances. Prevention and mitigation of wildlife fatalities, and protection of peat bogs, affect the siting and operation of wind turbines.
The most challenging environmental impact facing humans is that wind farms are usually placed within certain distances of people’s homes which there have been many instances of noise pollution and in the case of rural areas there has been many objections to the erections of wind farms in places deemed to be of significant beauty. To overcome this there needs to be a change in the way people see wind farms and also there needs to be an increase in the development of noise reduction around wind farms.
3.4 Biofuel Energy
Ireland generates 849 GWh of electricity which accounts for 1.1% of Ireland’s overall electricity generation.
3.4.1 Short Rotation Forestry
Short rotation forestry is the production of wood fuel through the cultivation of high-yielding trees at close spacing on short time rotations. Species such as willow and poplar are ideal for short rotation forestry, as they are easy to establish, fast growing, suitable for a variety of sites and resistant to pests and disease.
Land for short rotation forestry is likely to come from two sources, namely: non-rotational arable set aside land and land outside the existing arable pool – currently in beef or sheep production. [18]
3.4.2 Liquid Biofuel Energy Crops
Crops are grown for the production of liquid transport fuels. Different conversion techniques are used to produce biodiesel, bioethanol and biomethanol. Biodiesel is derived from oil crops such as oilseed rape and camelina (an oil-seed crop with an oil yield similar to that of oilseed rape). Bioethanol is produced from crops such as wheat, sugar beet, sweet sorghum and woody crops. Research on the production of biomethanol from various biomass sources such as grasses, short rotation forestry, crop residues and municipal solid waste is ongoing. Liquid biofuels can be incorporated as blends with petrol/diesel fuels or used on their own as a replacement fuel. [18]
3.4.3 Wood Wastes
Wood wastes or by-products from wood processing industries e.g. chips, bark and sawdust. These are used within sawmills and board mills to provide heat for drying or space heating and to raise steam for the manufacturing process. However, surplus quantities are generally available on the open market. [18]
3.4.4 Agricultural Residues
Agricultural residues e.g. animal slurry and manure, chicken litter, spent mushroom compost and straw. Disposal of some of these residues poses an environmental problem. It is estimated that the total amount of agricultural waste in Ireland in 1998 was approximately 65 million tonnes. Wet wastes such as cattle and pig manure are suitable for anaerobic digestion, while wastes with a lower moisture content e.g. chicken litter and spent mushroom compost can be combusted. [18]
3.4.5 Sewage Sludge
Municipal solid waste , food processing waste, and sewage sludge – all of these wastes can be converted to energy, in the form of biogas, through the process of anaerobic digestion. The organic fraction of municipal solid waste is collected from households and commercial premises etc. It is estimated that over two million tonnes of municipal solid waste were produced in Ireland in 1998. Sewage sludge is a by-product of wastewater treatment. With EU regulations influencing the treatment of waste, increased amounts of wastes are available as a source of affordable biomass fuel. [18]
3.4.6 Forest Residues
These consist of the tree tops and branches that remain after timber is harvested. Some forest residues need to be left on the forest floor to decompose and return nutrients to the soil and also to act as brash mats, which allow machinery to travel across soft ground. However, a lot of this material could be harvested with suitable machinery and used as a renewable fuel for energy production. [18]
3.4.7 Biofuels Issues
There are a number of issues with the regard of biofuels These include: the effect of moderating oil prices, the foo vs, fuel debate, poverty ruduction potential, carbon emmissions levels, sustainable biofuel production, deforestation and soil erosion , loss of biodiversity, impact on water resources, as well as energy balance and efficiency. [19]
3.5 Solar Energy
Solar energy is not a major source for the generation of electricity in Ireland most solar energy generation in Ireland is used for heating homes. Photovoltaic electricity is used in micro-generation (up to 6kwh) usually in homes and businesses.
3.5.1 Photovoltaic Generation
Photovoltaic generation converts solar radiation into direct current electricity using semiconductor that exhibit the photovoltaic effect. Photovoltaic power generation employs solar panels composed of a number of solar cells containing a photovoltaic material. Though the photovoltaic effect is directly related to the photoelectric effect, the two processes are different and should be distinguished. In the photoelectric effect, electrons are ejected from a material's surface upon exposure to radiation of sufficient energy. The photovoltaic effect is different in that the generated electrons are transferred between different bands (i.e., from the valence to conduction bands) within the material, resulting in the buildup of a voltage between two electrodes.
In most photovoltaic applications the radiation is sunlight and for this reason the devices are known as solar cells. In the case of a p-n junction solar cell, illuminating the material creates an electric current as excited electrons and the remaining holes are swept in different directions by the built-in electric field of the depletion region. [20]
4.0 Investigation
Table 1 shows the percentage of fossil fuels and renewable energies used to generate Ireland’s energy demands. Ireland used Gas to generate 61.8% of their energy while only 12.9% is generated from renewable energies. Not only does this consumption of Gas to generate electricity have a significant cost (with Gas prices rising) it also has a great environmental impact.
4.1 Total amount of Energy used to generate Irelands electricity demands
As seen in Fig. 8 the total amount of fossil fuel and renewable energy used to generate Irelands electricity demands is 4927 ktoe (kilo ton of oil equivalent). To convert this into GWh we need to multiply by a conversion factor of 11.63. This was done using the conversion websites [2]. Shown below is a table of all the GWh produced using the various types of fossil fuels and renewable energy generating techniques.
Table 3 - Total amount of GWh produced in Ireland using fossil fuels and renewable energy.
4.2 Emissions by Fuel Source
Using the website [3] the amount of CO2 that is emitted was calculated for the fossil fuels only. While the renewable energy may contribute to some carbon emissions in the manufacture or the running of the process this is so small compared to the burning the fossil fuels that it is regarded as 0. Each fossil fuel has a specific amount of CO2 that is produced for each GWh produced. The table below shows that amount CO2 generated.
Table 4 – Total amount of CO2 emitted for each fossil fuel
4.3 Cost
The total cost of fossil fuels (commodity) to purchase for the generation of the electricity is was taken from reference 7. Each of the commodities was given in different volumes in which they were traded. Each commodity is changed to it equivalent ktoe and then multiplied by its commodity price which calculated the total spend each year on commodities for generating electricity.
Note: Peat is not traded and is usually sourced in Ireland [1] and as this is on the decline this factor was neglected.
Table 5 – Total spend on commodities 2010
4.4 Totals
Table 6 - Total figures for the amount of energy needed (ktoe), generated (GWh), emissions (kTon/GWh), commodity price (variable) and total spend per year.
4.5 Reductions
The outline of this report is to see how much CO2 and how much money will be saved if Ireland was to reduce its generation of electricity using fossil fuels by 10%.
Table 7 – Amount of CO2 emissions saved and the amount of cost saved if using fossil fuels were reduced by 10%. Also shows the amount of electricity needed to be generated using renewable energy.
5.0 Recommendations
It is shown that Ireland generates 57278 GWh of electricity for consumption of this 35169 GWh is produced by gas. This amounts to 61.4% of all the electricity generated by gas. The burning of this fossil fuel creates 6457kton/GWh; this is all at the cost €330,005,707 a year. As this is the biggest contributor to the generation of electricity it is recommended that natural gas production be reduced. The money that would be saved will increase year on year as the cost of natural gas rises in line with the rise in oil prices. As seen from the table 7 the reduction by 10% using natural gas for electricity generation has significant savings in cost and in emissions but investment would need to be made to make up the difference in taking the gas plants offline.
As Ireland is currently generating 9.7% of its electricity using wind energy, this is the largest renewable energy used for the generation of electricity in Ireland. Investing in more wind farms is recommended for increasing the amount of electricity generated from renewable sources. As Ireland is currently investigating wave energy and looks promising for suitable generation. Ireland needs to follow the German model of using solar energy for electricity generation on the mass scale. The possibility of installing of another pumped storage hydro-electric dam is also promising. There is no 1 method of renewable energy generation that is recommended but a combination of several methods.
There are a number of ways to save on cost arising from the generation of electricity is increasing the reliability and the efficiencies of the power generators, this would save on massive investment while increasing output.
References:
[1]. Energy Security in Ireland (2011 Report) – SEAI (Sustainable Energy Authority Ireland)
[2]. www.iea.org/stats/unit.asp (energy conversion calculator)
[3]. http://www.carbontrust.co.uk/cut-carbon-reduce-costs/calculate/carbon-footprinting/pages/conversion-factors.aspx (Carbon Factor Calculator)
[4] http://www.indexmundi.com/commodities (Commodity prices)
[5] http://www.rigzone.com/calculator/default.asp#calc (Conversion Calculator)
[6] http://www.unitjuggler.com/convert-energy-from-ktoe-to-GcmNG.html
[7] http://www.conversion-website.com/energy/ton_of_oil_equivalent_to_ton_of_coal_equivalent.html
[8] http://www.eirgrid.com/media/Connected%20(Non-Wind%20Generators)%20-%2030%20Sep%202011.pdf
[9] http://en.wikipedia.org/wiki/Risks_to_the_Glen_Canyon_Dam
[10] http://www.seai.ie/Publications/Renewables_Publications/Tidal_Current_Energy_Resources_in_Ireland_Report.pdf
[11] http://en.wikipedia.org/wiki/Wave_power#Challenges
[12] http://en.wikipedia.org/wiki/Tidal_power
[13] http://www.seai.ie/Renewables/Ocean_Energy/
[14] http://www.seai.ie/Renewables/Wind_Energy/
[15] http://en.wikipedia.org/wiki/Wind_turbine#Vertical_axis_design
[16] http://en.wikipedia.org/wiki/Wind_turbine#Horizontal_axis
[17] http://en.wikipedia.org/wiki/Environmental_effects_of_wind_power
[18] http://www.seai.ie/Renewables/Bioenergy/intro_and_biomass_sources
[19] http://en.wikipedia.org/wiki/Issues_relating_to_biofuels
[20] http://en.wikipedia.org/wiki/Photovoltaic_effect